172: Chapter 172 Orders

September 29, 7:12 AM.

On an autumn morning in this northern heavy industrial city, the surface morning mist had not yet completely dissipated, but rows of white industrial lights had already lit up below the No. 3 operation and maintenance entrance of the underground utility tunnel located on the city's outskirts.

The stern LED light source illuminated the deep concrete passage as bright as day.

The 2.8-kilometer-long verification section had been temporarily closed.

The metal gate at the entrance of the passage was tightly closed, and a red warning light flashed regularly on the lintel.

Representatives from the operation dispatch center, fire linkage supervisors, group data security heads, technical stay-behind personnel from the original equipment supplier, and the maintenance team stationed in the dark underground year-round had respectively completed their sign-ins on the paper test plans.

By the wall of the entrance verification line, several items were neatly placed.

Two red metal toolboxes filled with heavy wrenches and hydraulic pliers, an emergency electric trailer with anti-slip tracks, and the yellow nylon tow strap used in the previous failure recovery mission.

Maintenance team leader Lao Zhao squatted by the wall, his rough fingers slowly sliding across the surface of the nylon tow strap.

The tow strap had just been washed with a high-pressure water gun yesterday afternoon.

The black mud, foul-smelling accumulated water, and dust on the surface had disappeared, but after enduring ultimate tensile forces several times, the layer of fine burrs left on the surface of the nylon fibers at the stressed positions still remained.

Lao Zhao picked up the nylon strap from the ground, checked the heavy metal hooks at both ends one by one according to the emergency recovery plan on site, confirmed that the spring buckles were not rusted or stuck, and then coiled it up circle by circle again.

Last time, he and his apprentice walked in through this very door.

That exhausting afternoon.

Wearing heavy anti-static work clothes and stepping on accumulated water of varying depths, they walked all the way to 1.37 kilometers away.

There, they found that expensive tracked robot which claimed to solve all underground inspection pain points.

It lay beside the drainage ditch, its indicator lights still flashing, with sixty-three percent of its internal battery remaining, but the over-temperature protection of the main drive module had cut off all power output.

Lao Zhao closed his eyes, as if he could still feel the sense of suffocation from that day.

The apprentice pulled this nylon strap in front, his body leaning to an angle almost close to the ground.

He pushed against the robot's cold metal shell with his shoulders from behind, his shoe soles constantly slipping in the slick muddy water.

A full seventeen minutes.

They didn't even manage to drag that heavy scrap of steel out of half the distance of the verification section.

The stuffy environment with poor ventilation and extremely high humidity made every breath feel like swallowing a warm, wet sponge.

"How heavy is it?" Lao Zhao raised his head, looking at Project Engineering Manager Director Chen, who was repeatedly confirming the schedule.

"The whole machine is under two hundred kilograms." Director Chen looked at the test application form in his hand and replied without raising his head.

Lao Zhao steadily placed the coiled nylon strap on the pedal of the emergency trailer, and said in a voice with almost no emotional fluctuations: "Once it breaks inside, the reducer is difficult to drag backward. Coupled with the ground friction, these two hundred kilograms are not light either. It is best not to let us go in and do coolie work today."

Director Chen finally stopped what he was doing and turned his head to glance at Lao Zhao.

This remark sounded a bit harsh on this occasion, but Director Chen knew that this was not a malicious query, but the most genuine fear of a frontline worker who had been struggling underground for years.

Over the past two years, their key utility tunnel project had tried four different forms of intelligent inspection platforms.

The first one was a four-wheel-drive solution, but its chassis was too low and got stuck on the edge of the first sump.

The second one was a tracked solution; its obstacle-crossing ability was sufficient, but when passing through expansion joints, its posture bumped like a fish struggling on the shore, and the instrument panels captured by the camera were all blurred double images.

The third one was a composite chassis claimed to integrate the advantages of wheeled and legged types, but its mechanical structure was too complex, and the connecting rods jammed after soaking in muddy water for half a day.

...

It was not that these platforms had not passed factory tests.

On the contrary, every single indicator could pass inspection.

The problem was that a real utility tunnel would simultaneously pile accumulated water, expansion joints, sealing, communication blind spots, and four hours of continuous load onto a single machine.

Those inconspicuous concrete expansion joints, those drainage ditches designed to be only three centimeters wide but covered in oil stains, those shallow waters accumulated in the rainy season, those communication dead zones where all high-frequency radio waves disappeared, and hours of uninterrupted, continuous, high-intensity operation...

The cruel Physics reality inside the utility tunnel would retranslate every adjective in the manual into overload, shutdown, short circuit, and collapse.

The equipment participating in the test today had not yet reached the underground.

Director Chen had already raised his wrist to look at his watch for the third time.

"They confirmed with me last night that they will definitely arrive before eight in the morning." Director Chen seemed to be answering Lao Zhao, and also comforting himself.

7:34 AM.

Accompanied by a dull roar of motors, the metal double doors of the heavy freight elevator slowly opened to both sides.

The morning cold air poured into the underground along the elevator shaft.

Five figures wearing anti-static work clothes pushed a hydraulic pallet truck and walked out of the elevator car.

Walking at the very front was Liang Zhixia.

Today, she was wearing a neatly tailored black jacket, her hair neatly tied back, and her eyes were cold and focused.

Chen Yan and two other young test engineers from Low Entropy Workshop stood on both sides of the hydraulic pallet truck, steadily guarding the huge black engineering plastic transport box above.

Jiang Lin walked at the very end of the team, holding a black industrial rugged terminal encased in a heavy drop-proof shell.

Director Chen hurried forward, his gaze involuntarily falling on the black transport box.

On the outside of the wide box body, only an ordinary self-adhesive white label was pasted next to the buckle.

[G-01 C-PG]

[Underground Utility Tunnel Engineering Verification Machine]

[Prototype Number: PG-01]

Chen Yan flipped open the high-strength alloy locks with a sense of damping one by one.

Accompanied by four crisp metal snapping sounds, the box panels, assisted by hydraulic support rods, steadily lowered to both sides like petals, revealing the true appearance inside the shock-absorbing foam.

A grayish-black hexapod robot appeared in everyone's line of sight.

At that instant, the entire No. 3 operation and maintenance entrance fell into a brief silence.

Everyone, including the stay-behind personnel of the original equipment supplier, focused their gazes on this machine.

In terms of overall basic outline, it still maintained an astonishing degree of similarity with the G-01 C that caused a sensation at the World Robot Conference more than a month ago, but its temperament was completely different.

The original G-01 C carried the roughness and hardcore feel of being handmade, while the PG-01 before them exuded a pragmatist industrial sense of oppression.

Its body was deliberately pressed very low, and its six stout mechanical legs were compactly retracted on both sides of the body in a slightly bent posture ready to exert force at any time.

The surface of the mechanical legs was sprayed with anti-corrosion matte black coating, and the motors at the joints were closely wrapped by thick metal protective covers.

The most significant change lay in the upper half.

A set of environmental perception modules protected by high-light-transmittance quartz glass was added to the front and back respectively.

Below the belly of the machine, the originally exposed wiring harnesses and bottom cover were completely sealed off by an aviation aluminum alloy protection plate up to five millimeters thick.

On its wide back, a square-shaped sealed mission cabin was steadily fixed.

On the side of the mission cabin, thermal infrared imaging lenses, tens-of-millions-of-pixel visible light industrial cameras, and multiple gas concentration detection modules exhibiting different opening shapes were densely and orderly arranged.

Overall, it didn't look at all like a high-tech robot preparing to perform on stage under the spotlight.

It looked more like a tool that was well aware of what harsh environments it was going to face.

Director Chen slowly walked around the opened transport box, his gaze sharply sweeping over every detail of the machine.

Finally stopping in front of the PG-01, he looked up at Liang Zhixia: "Director Liang, is this the utility tunnel version you made?"

Liang Zhixia nodded: "This is the first engineering verification machine customized for the special working conditions of the utility tunnel."

Director Chen's brow furrowed slightly, with undisguised doubt in his eyes: "From the time we confirmed the thermal path test in the video conference until now, only six days and nights have passed. For the research and development, processing, assembly, and testing of an industrial-grade equipment, even if your people don't sleep, this time span is too challenging to common sense."

"The chassis kinematics model and core underlying control system are ready-made, and we had already completed millions of levels of simulations before the conference." Liang Zhixia pointed to the machine's legs, "This time, what we need to solve is only the physical survival problem in this specific scenario."

Chen Yan had already stepped forward at this time, plugging the thick data cable in his hand into the external inspection terminal interface at the rear of the PG-01's body.

Accompanied by a low electronic beep, the screens in Chen Yan's hand lit up one by one.

The green status bar began to scroll rapidly, displaying one by one the absolute encoder status of the six sets of mechanical joints, the initial load calibration values of the twelve foot-end sensors, the micro-positive pressure sealing status of the back mission cabin, and the health and power margin of the power battery module.

All indicators entirely presented a bright green representing health.

The facts were just as Liang Zhixia said.

From the night of September 23, when it was verified that the rise in shell temperature was the correct path for heat dissipation, until dawn today, Low Entropy Workshop did not manufacture a brand-new robot from scratch.

Time did not allow it, and engineering logic did not allow it either.

They did something cooler.

Jiang Lin ordered a Physics disassembly of the G-01 C prototype used as an exhibition sample, almost to the point of dismemberment.

They first removed all non-essential presentation modules, reducing a full nineteen kilograms of invalid dead weight.

Subsequently, Jiang Lin personally took charge, implanting the long-cycle thermal management topology structure that he had sealed in the underlying database after returning from the eleventh Wasteland into the Physics shell of this machine.

This was a very challenging integration process.

They added an inspection task module exclusive to the utility tunnel, which meant that the power consumption of the whole machine increased by fifteen percent.

To cope with this increased heat, Jiang Lin redistributed the Physics heat outlets inside the body.

Utilizing the thermal conductivity and surface area of the body structural components themselves, he constructed a complex passive thermal conduction network.

But the Physics laws of the Real World never compromise easily.

In the first version of the fully sealed cabin continuous load operation test conducted in the early morning of September 25, when the time on the test bench reached two hours and seventeen minutes, the temperature control thermal imager showed that one of the internal main power supply harnesses, because it was close to a high-density thermal conductive copper bar, had a local temperature exceeding the insulation design range of the wire skin, emitting a dangerous scorching smell.

Without hesitation, Jiang Lin directly pressed the stop button.

Disassemble.

Discarded three expensive custom wiring harnesses.

Redesigned the internal electrical wiring, added heat-insulation mica sheets, and changed the routing.

On the afternoon of September 26, the second version of the prototype was formed.

In the subsequent bench test, the machine successfully survived four hours of continuous ultimate load.

Before everyone had time to celebrate, Chen Yan discovered a dangerous detail while reviewing the recording.

Due to the high heat and humidity characteristics of the utility tunnel simulated environment, inside a front-side visible-light camera lens external to the back mission cabin, when running to three and a half hours, an intermittent fogging phenomenon that was extremely difficult for the naked eye to detect appeared.

This was absolutely not allowed in utility tunnel inspections; a blurred lens would cause the instrument panel recognition rate to drop to zero.

There was no room for bargaining at all.

Jiang Lin gave the order once more.

Disassemble.

Replaced the material of all flange sealing rings, added a replaceable miniature desiccant chamber inside the camera module, and redesigned the heating gradient of the lens to ensure that the temperature of the glass surface was always slightly higher than the environmental dew point temperature.

On September 28, which was yesterday.

The third version of the prototype finally ushered in the ultimate mechanical exam.

Inside the temperature-controlled enclosure box, dragging a fully loaded mission cabin, it completed a six-hour continuous heavy-load test.

The external simulation bench constantly applied resistance, and the six mechanical legs repeatedly walked at an extremely high frequency for a full four hundred times on the simulated drainage ditch and expansion joint test platform.

Every footing, every peak of joint torque, and every minor fluctuation in internal temperature were recorded as massive amounts of data by the recorder.

Until late last night, or even early this morning, under Jiang Lin's final authorization, was this verification machine named PG-01 pushed out from the temperature-controlled enclosure box of the temporary Beijing R&D Center and packed into this black transport box.

During these short and crazy six days, the directly scrapped parts left behind by the entire R&D Center were actually not many.

What truly kept piling up was a stack of test records filled with red annotations.

As well as the gray plastic parts box with an eye-catching red label quietly placed next to the transport box at this moment.

The label read four large characters: [Do Not Reinstall].

Inside were eliminated thermal pads, deformed sealing rings, and wiring harnesses of unqualified lengths.

Director Chen stopped in front of this parts box.

He squatted down, his gaze passing over the thick external armor of the PG-01, trying to see the structure inside the body through the gaps.

Director Chen raised his head and looked at Jiang Lin, who had remained silent all along: "Engineer Jiang, I took a rough look at your electrical interfaces. You didn't use our original set of drive modules?"

"No."

Jiang Lin's reply was so crisp that Director Chen was surprised: "Then what about the sealed control cabin that we spent a lot of money to customize? Was that not used either?"

"Not used either." Jiang Lin remained calm.

Director Chen stood up and patted the dust off his hands.

In the expectations of the past few days, he originally thought that Low Entropy Workshop, as a start-up company, in order to save cost and time, would provide a patchwork thermal management retrofit and optimization solution for that stalled tracked platform based on the detailed failure data they provided earlier.

After all, this was also the most common practice in the industry.

Add a copper bar, modify an air duct, or even externally attach a cooling pack.

Until last night, when he received the final entry test material list sent by Low Entropy Workshop from the encrypted email, he was somewhat shocked to find that what was about to enter the utility tunnel was not some retrofitted old machine at all.

But a new-form hexapod robot independently developed by Low Entropy Workshop with completely independent intellectual property rights.

"Then a few days ago, during the video conference, you forced us to hand over the underlying runtime logs, and even spent the whole night replicating the faults of our old platform on the test bench in such detail. What on earth was that for?"

President Chen looked into Jiang Lin's eyes, his tone carrying the persistent questioning of someone whose worldview had been completely upended.

"To determine where the faults on-site primarily stem from in terms of their physical essence." Jiang Lin met his gaze, his tone cold and stern.

"And after determining that? Then bypass it and patch the old machine?" President Chen pressed further.

Jiang Lin shook his head slightly.

Low Entropy Workshop had never intended to act as a patcher from the very beginning.

They had neither the interest nor the preparation to help the previous machine, which was full of design compromises, move another three hundred meters forward.

What they wanted to do was overthrow the old paradigm and replace it with a machine that could truly define the rules of this scenario.

7:53 AM.

There was less than twenty minutes left until the expected departure time.

The pre-test confirmation process on-site entered its most sensitive phase.

Lao Liu, the project party's data security head, walked forward carrying a laptop.

His responsibility was to ensure that this external machine would not become a mobile loophole leaking core spatial data when entering the interior of the national-level infrastructure.

"Engineer Jiang, we must verify the data storage and transmission path one last time." Lao Liu pushed up his glasses, his gaze severe.

"All external environment data generated by PG-01 within the verification section, including visible light recordings, infrared thermal imager maps, toxic and harmful gas concentration readings, and all instrument recognition results, are all saved as raw runtime logs in real-time and exclusively inside the hardware-encrypted recording box within the machine body."

Jiang Lin methodically explained Low Entropy Workshop's isolation plan.

"The first landing point of the full volume of raw environmental data generated by PG-01 is the hardware-encrypted recording box inside the machine body."

"The on-site read-only terminal receives low-bitrate preview images, task results, and runtime status mirrors within the range agreed upon by the project party through a unidirectional link. After the test, both parties will complete the raw data handover and hash verification in an offline state."

"The entire device does not connect to the external network, nor will it upload any maps, images, or spatial structure data to Low Entropy Workshop's cloud server."

Lao Liu glanced at the black terminal in Jiang Lin's hand: "Then what do you retain?"

"The project party can obtain all task execution results, objective environmental records, and the machine's superficial operating status within the scope agreed upon in our contract, such as battery percentage, apparent motor temperature, and current mileage."

Jiang Lin paused, his tone turning non-negotiable.

"The complete logs of the motion control chain, safety state machine, and parameter generator are saved in an independent encrypted partition. The project party cannot parse them; they do not enter the project party's data domain nor are they uploaded to the cloud. After the test, they can only be read offline by Low Entropy Workshop's authorized terminal."

Lao Liu was silent for a moment. After tapping a few keys on the keyboard and confirming that the unidirectional diode isolation hardware of the underlying physical port was active, he nodded and retreated to the monitoring console.

President Chen walked over to a floor plan of the pipe gallery entrance verification section posted on the whiteboard, picked up a red marker, and tapped heavily on it several times.

"Let us verify the task objectives again. On this 2.8-kilometer route, a total of forty-seven task points have been set up."

President Chen turned around and looked at Low Entropy Workshop's team: "There are nineteen key instrument reading recognitions along the way, including high-voltage cabinet panels and liquid level gauges. There are nine thermal infrared anomaly scanning points, focusing on the joint positions of the cable trays. There are twelve visual inspections for wall and roof leaks. And there are seven hydrogen sulfide and carbon monoxide environmental concentration records."

"The destination is located in front of the iron door of the second fire partition at a physical distance of 2.8 kilometers."

"Upon reaching the destination and completing the final reading, no turning area will be provided; the machine must turn around by itself within the narrow passage and return along the original route. The entire process requires absolute autonomy."

Jiang Lin lowered his head to look at the terminal screen. The backend had completed the final SHA-256 hash verification of the task route preset configuration file.

"Verification passed, configuration matches the drawings."

Jiang Lin raised his head and asked, "I need to confirm an external variable: during the verification period, are any maintenance personnel scheduled to enter and work inside this section of the pipe gallery?"

"No, the entire section is cleared." Lao Zhao replied from the side.

"How is the on-site remote control permission defined?" Jiang Lin continued to ask.

"To cope with potential out-of-control or collision risks, we only retain a highest-priority global emergency stop command at the entrance monitoring console."

President Chen replied, "Aside from that, during normal task execution, the machine does not accept and should not need any form of manual remote control joystick input. What we want is an inspection, not a remote-controlled toy."

Hearing this, Lao Zhao couldn't help but take a step forward.

As the frontline maintenance squad leader, he knew the communication conditions deep inside this pipe gallery better than anyone else.

"President Chen, Engineer Jiang."

Lao Zhao's brows furrowed into the shape of the Chinese character 'chuan', "There are several signal blind spots starting two thousand meters inside. What if the communication drops? Our image transmission and commands can't get in, what should the machine do?"

All eyes focused on Jiang Lin.

In past tests, this was often the fatal flaw of all robots.

"Continue executing the current node and its subsequent queue tasks."

Jiang Lin replied without the slightest hesitation, his voice sounding exceptionally clear in the empty entrance, "PG-01's core edge computing module possesses complete local path planning capabilities. Losing external communication does not equal losing mobility."

"What if the situation inside exceeds expectations?" Lao Zhao pressed on, "For example, if the accumulated water suddenly deepens, or its battery drains too fast?"

"If the machine's underlying safety state machine comprehensively judges that the current physical conditions can no longer simultaneously meet the two hard constraints of completing the remaining tasks and retaining sufficient return battery margin."

Jiang Lin looked at Lao Zhao and said word by word, "It will immediately abort the task and retreat on its own."

"After retreating, does this test count as passed?" Lao Zhao asked the most realistic question.

"It counts as an uncompleted task, belonging to project failure." Jiang Lin answered openly.

"But the machine has to come back by itself?"

"It must come back by itself." Jiang Lin said, "The first principle of its design is not to add extra workload to humans."

Hearing this, Lao Zhao took a deep breath, turned his head, and looked with a complex gaze at the nylon tow strap by the wall that he had just coiled up.

This was the only part he truly and solely cared about.

He didn't care how clear photos this machine could take; he only cared whether, when this machine ran into trouble in the dark, it would choose to lie there like a dead object waiting for humans to rescue it, or like a truly independent entity, exhaust every effort to walk out on its own.

8:06 AM.

As Chen Yan pressed the [System Wake-up] command on the test terminal, the PG-01, which had been quietly lying in the transport box, slowly stood up like a mechanical beast infused with a soul.

Driven by servo motors, the six thick mechanical legs successively performed a minimal-amplitude extension and calibration action.

The entire process was silent, with only the faint sound of joint current.

Unlike those behemoths that easily required cranes or three or four people working together to lift onto the ground, after PG-01 stood up, its body was deliberately kept at an extremely low center of gravity, and the overall body was only raised by less than half a meter.

This low posture gave it a natural passability advantage when facing the intricate pipes and low-hanging cable trays inside the pipe gallery.

About fifteen seconds later, the system kernel self-check was completed.

It did not wait for any staff on-site to step forward to carry, push, or pull it.

Under everyone's gaze, this hexapod robot took steady steps, walking step by step steadily onto the floor tiles of the pipe gallery along the aluminum alloy inclined plate lowered at the front of the transport box.

The specially made anti-slip polymer rubber pad at the foot end landed on the somewhat slippery anti-slip floor tiles, making a continuous clicking sound of touching the ground.

Xiao Zhang, the thermal design engineer of the project party, was standing closely beside the monitoring console at this moment, staring intently at the backend temperature monitoring panel transmitted back in real-time via the local network on the screen.

"Engineer Jiang, pre-start data confirmation."

Xiao Zhang's voice carried professional tension, "The pipe gallery ambient temperature is thirty-three degrees. After PG-01 entered the site, it stood still for temperature equalization for thirty minutes, and the initial temperature of the shells on both sides of the machine body is thirty-two point eight degrees."

Chen Yan stood nearby, holding a stack of test data sheets, and nodded.

"Today, we are not looking at whether its shell is cool or not." When Chen Yan said this sentence, his gaze turned to Xiao Zhang.

Xiao Zhang understood the engineering logic behind this sentence, and his face blushed slightly.

Six days ago, the original equipment supplier still regarded the ice-cold shell as evidence of good heat dissipation.

PG-01 was the exact opposite.

Jiang Lin reserved two exposed aluminum alloy areas on both sides of the machine body to actively guide the heat generated by the driver and computing platform to the shell.

As long as the internal temperature no longer rose, the shell temperature rising was not an alarm, but proof that the thermal channel was working.

8:12 AM.

The time on the large monitoring screen ticked over punctually.

Jiang Lin pressed the confirmation key on the black terminal.

The verification task officially started.

PG-01's rear indicator light switched from standby blue to the steady green of executing tasks.

It strode with its six mechanical legs, steadily crossing the verification start line pasted on the ground with yellow tape.

Ahead of it was a concrete corridor so long and deep that it seemed endless.

The intricate pipelines on both sides resembled the blood vessels of some huge creature, extending all the way into the depths of darkness along the mottled walls.

Overhead, explosion-proof ceiling lights lit up one after another in the distance as it moved forward, as if guiding this lonely deep-diver.

For the first two hundred meters, the ground belonged to newly poured flat concrete without any physical obstacles.

PG-01 displayed a reassuringly boring and stable performance here.

It maintained a fixed cruising speed of 0.8 meters per second, moving forward at a uniform speed.

There was no redundant shaking, nor any fancy actions generated for showing off skills.

Whenever it approached the preset task coordinate points, it would stop precisely.

Pause.

The high-definition gimbal camera on top of the rear task compartment would quickly lift, and the lens aperture would complete adjustment within a microsecond-level time, accurately locking onto the liquid level gauge or barometer of the high-voltage cabinet above the wall.

Scan, take pictures.

The image recognition algorithm instantly completed digital extraction in the edge computing module.

At the same time, the lateral thermal infrared module silently swept across the thick cable trays, searching for any minor abnormal temperature rise points that might be caused by poor contact.

On the screen of the monitoring console, rows of green status information began to scroll and refresh downwards at a comfortably rhythmic pace,

[SYS_LOG: Relative Distance 0.05 km]

[Task Point 01_High-Voltage Instrument Recognition: Complete. Numerical Verification: Normal.]

[SYS_LOG: Relative Distance 0.12 km]

[Task Point 02_Roof Leakage Visual Judgment: Complete. Status: Dry.]

[SYS_LOG: Relative Distance 0.18 km]

[Task Point 03_Cable Tray Infrared Scanning: Complete. Maximum Temperature Difference: 2.1 ℃.]

When the test had just begun, President Chen was still standing with his hands behind his back, looking solemn at the very front of the monitoring screen, as if supervising a major battle.

But just ten minutes later, when he saw the task execution process on the screen that was as precise, boring, and utterly wave-less as clock gears, he silently walked to the side, dragged over a folding chair, and sat down next to Lao Liu, the data security head.

As a veteran who had been through the mill on the frontline of engineering for twenty years, he was as clear as a mirror in his heart.

Walking 2.8 kilometers on a flat road could not count as a technical challenge at all.

Randomly find a civilian wheeled chassis worth tens of thousands of yuan on the market, give it sufficient power, and the distance it runs on flat ground could even far exceed this number.

What truly made people feel tricky about the pipe gallery environment was never the length of absolute distance.

Its malice was deeply hidden in those seemingly inconspicuous ground changes full of physical variables ahead.

When the number of the relative odometer jumped to eight hundred meters, the picture on the screen finally changed.

The atmosphere in front of the monitoring console tightened instantly.

Because the first continuous expansion joint appeared.

Due to the uneven settlement of the pipe gallery foundation, although the joint width of these two expansion joints was not large, the concrete at the edges had fragmented and bulged due to long-term moisture and squeezing, forming a misalignment height difference of about four centimeters.

The four-wheeled platform tested here in the past had its rubber tires repeatedly slipping in front of this height difference, eventually triggering current protection due to motor overload.

As for the tracked platform, although it relied on strong grip to forcefully crush across, the huge rigid impact generated the moment the tracks crossed was transmitted without reservation along the metal chassis into the control cabin, causing the camera gimbal working at the time to experience violent oscillation, and the instrument photos taken back were all a blur of afterimages.

In the monitoring screen, PG-01 actively reduced its cruising speed less than one meter away from the expansion joint.

Its six eyes had already constructed a three-dimensional model of the terrain ahead within a fraction of a second through the fusion point cloud data of structured light and lidar.

It did not choose to brutally crush across like a tracked vehicle.

When the two mechanical legs on the front side approached the edge of the gap, the servo motors exerted a slight force, and the foot ends, as if probing, precisely crossed the raised concrete broken edge and stepped steadily onto the flat ground on the opposite side.

Subsequently, the two load-bearing legs in the middle quickly performed a dynamic redistribution of support points and center of gravity.

Afterwards, the two mechanical legs on the rear side also followed up and crossed with the same posture.

The entire crossing process was smooth and flowing, without any stagnation.

What was even more shocking was that during this crossing action lasting several seconds, the horizontal height of the heavy machine body carrying precision instruments above PG-01 only showed a weak fluctuation whose magnitude was almost negligible.

President Chen stared intently at the attitude curve representing the body pitch angle in the corner of the screen.

When the crossing occurred, that curve only rippled with a tiny ripple, and immediately returned to a straight horizontal line.

There was no continuous oscillation, and no out-of-control aftershocks.

"With the length and joint degrees of freedom of its legs, it could easily take big strides to step right across like an animal, and the speed would be much faster."

President Chen couldn't help turning his head to look at Jiang Lin and raising a question, "Why does it choose such a small stride, moving slowly in a nearly translational manner?"

"Because it carries a mission module on its back, which is equipped with high-precision optical instruments."

Chen Yan, standing aside, answered for Jiang Lin, "The greater the magnitude of the mechanical action, the larger the absolute value of the system's center of gravity deviation, and the longer the settling recovery time required for the fuselage to re-establish dynamic balance after crossing."

Chen Yan pointed to the fuselage posture on the screen: "In industrial scenarios, PG-01 was designed never to show humans how high its mechanical legs can lift, or how pretty bionic movements it can make."

What it needs to do is simply cross obstacles with minimal energy consumption and the smoothest fuselage posture, and then continue working without interruption.

President Chen nodded silently and said no more.

Nine hundred and forty meters.

As the terrain of the pipe corridor sank slightly, the accumulated water on the ground began to increase noticeably.

The water depth gradually rose from the initial two centimeters, which barely covered the soles of the shoes, to close to seven centimeters.

In the surveillance footage, this accumulated water area presented a deep dark black color.

Due to the oil stains and dust peeling off the pipe walls floating on the water surface, the water body was very turbid, making it completely impossible to see the real ground conditions underwater.

The six foot-ends of PG-01 stepped into the water without hesitation.

When the special rubber stepped into the accumulated water, it stirred up circles of small and viscous ripples.

The water surface just submerged the lowest ankle joints of its mechanical legs.

Suddenly, the advancing speed of PG-01 showed a noticeable drop.

It paused for a moment.

President Chen immediately became nervous: "Why has it slowed down? Is there water entering the chassis?"

"It is not a hardware problem." Jiang Lin looked at the multi-dimensional perception data matrix sent back from the backend: "The visual perception module ahead has encountered trouble."

The intense LED explosion-proof lighting at the top of the pipe corridor shone on the large area of black accumulated water surface, producing extremely strong specular reflection.

This complex reflective environment caused the binocular images carried by PG-01 to be severely overexposed, and the LiDAR echoes also produced large areas of voids and multipath noise.

In its visual algorithm, the ground ahead was no longer flat concrete, but a void filled with optical noise and completely chaotic depth information.

"Doesn't the data say that the historical maximum record of accumulated water in this area is only four centimeters?" President Chen turned his head to look at maintenance squad leader Old Zhao, his tone somewhat stern.

"President Chen, there was a heavy rainstorm in the city last night, and the underground water seepage surged." Old Zhao explained somewhat helplessly: "The automatic drainage pump ahead was blocked by sediment and was just repaired and restored to operation after six o'clock this morning. The seven-centimeter water depth now is already the result after pumping for two hours."

"Now that it's in a visual blind spot, can it still walk? Should we press the emergency pause button and send people inside to get it out?" As the data security director, Old Liu put forward the most conservative suggestion.

Jiang Lin did not touch the red stop button; his hands were even tucked into his pockets as he looked at the screen with a calm expression: "The machine's underlying state machine has not yet made a pause request."

Before the words fell, PG-01 in the surveillance footage made a move that exceeded everyone's expectations.

It did not blindly wade forward in place, nor did it choose to retreat.

Instead, the entire fuselage began to translate toward the right side of the pipe corridor by about twenty centimeters at an extremely slow speed.

On the right side, close to the edge of the drainage ditch, there was a narrow step left from the initial construction pouring, which was a few centimeters slightly higher than the central area.

The accumulated water there was relatively shallow, less than three centimeters.

PG-01 reselected a footing position.

Its right front foot probed underwater, avoiding a depression area that might exist and could not be confirmed by the vision system, and then used it as a new force-bearing point.

Accompanied by the faint sound of water, it began to continue moving forward slowly and firmly along this narrow, rugged, but relatively safe edge close to the wall.

No one drew this new obstacle avoidance route for it in the background.

There was no remote-control input intervention by human engineers through joysticks on the terminal at the scene.

Old Zhao stared dumbfounded at the grayish-black fuselage slowly moving on the screen, his lips slightly open: "How does it know this piece of ground in front of it cannot be trusted?"

"The confidence of the footing judgment given by the vision system is not enough." Jiang Lin pointed to the foot-end load curve. "It won't assume it can definitely step there just because it sees the ground. When vision is unreliable, the foot-end torque and contact feedback take over the judgment. Every step taken first gets evidence before transferring the weight over."

After the visual confidence decreased, the foot-end load became the main judgment basis.

One thousand one hundred and eighty meters.

When the relative mileage number jumped here, the air around the entire console seemed to become somewhat solidified.

For the project personnel at the scene, this was a coordinate with a cursed nature.

In the second field experiment, that old tracked platform with high hopes placed on it, which had its 550W high-power motor replaced, was precisely when crossing this distance that the temperature of the internal main drive module instantly went out of control, triggering a hardware shutdown.

Thermal design engineer Xiao Zhang stood up abruptly from the folding chair, his eyes fixed tightly on PG-01's real-time thermodynamic feedback panel.

"Engineer Jiang, the surface temperature of the exposed aluminum alloy armor on both sides of the fuselage has risen to forty-five degrees, which is twelve degrees higher than the ambient temperature."

Chen Yan tapped the keyboard a few times quickly beside him, pulling up the internal core temperature curve: "Main drive module inverter bridge junction temperature: seventy-two degrees. Central computing platform core temperature: sixty-eight degrees. The overall temperature rise slope has begun to flatten out, entering the dynamic thermal equilibrium zone."

PG-01 showed no signs of slowing down.

The high temperature on the fuselage shell was the physical proof that it was desperately radiating the internal destructive heat outward.

Those two raw aluminum alloy panels were like the two scorching lungs of the machine, greedily conducting heat exchange in the dark and humid pipe corridor.

One thousand three hundred and seventy meters.

This was where Old Zhao coiled that yellow nylon tow rope this morning.

This was the physical location where that old robot completely shut down for the first time and turned into a pile of scrap metal.

The industrial read-only terminal at the scene made a task prompt sound that was ordinary and even somewhat monotonous.

[ BEEP—— ]

[ SYS_LOG: Relative Distance 1.37 km ]

[ Task Point 23_Pipe Joint Infrared Scan: Complete. Status: Normal. ]

In the surveillance footage, PG-01 walked calmly past the location that once buried the hopes of countless projects with its regular alternating tripodal gait.

It seemed that in its logic, this was just one of countless ordinary coordinates in the long 2.8-kilometer journey.

Old Zhao turned his head and moved his gaze away from the screen.

He looked at the yellow nylon tow rope coiled neatly by himself next to the entrance gate.

Last time, deep in this tunnel, it was at a place beyond this distance that he took off his mud-stained gloves with exhaustion, leaned against the concrete wall covered with water droplets, and breathed heavily to rest.

And today, the grayish-black hexapod robot in the surveillance footage did not pause for even a step, having steadily continued walking toward the halo of the next explosion-proof light.

One thousand five hundred meters.

This was the furthest extreme distance that all other existing test platforms could reach under the premise of barely meeting the IP66 waterproof and dustproof sealing requirements.

President Chen's smartphone placed on the table suddenly vibrated violently.

The screen lit up, showing that the caller was two senior executives in charge of infrastructure and equipment procurement from the group.

He glanced at the caller ID and did not answer.

Before the test started, he had promised the leaders in the group's internal chat that he would report the progress every five hundred meters advanced.

However, after PG-01 truly crossed that life-and-death line of 1.5 kilometers, he stopped sending any messages.

Because for this machine, the limit test belonging to itself had just begun.

Two thousand and fifty meters.

As the depth of the pipe corridor further increased and the pipelines became extremely dense, the space here formed a severe wireless signal attenuation zone.

The penetrating power of the microwave signal was greatly weakened, and the pipe corridor officially entered a wireless network signal severe attenuation zone over two hundred meters long.

The surveillance footage on the console began to show obvious lag and pixelation.

The latency of the video stream rapidly soared from less than a second initially to an unbearable six seconds.

Immediately afterwards, accompanied by a red network disconnection icon popping up on the terminal screen, the video image completely froze.

On the on-site read-only terminal, the number representing the machine's current relative position despairingly stayed at the position of 2,108 meters and stopped jumping.

"It's broken, the communication is completely broken!" Old Zhao shouted.

Data security director Old Liu tapped his hands rapidly on the keyboard, inputting a series of diagnostic commands in an attempt to restart the network protocol stack.

After a few seconds, he shook his head, sweat seeping from his forehead: "It's not a hardware problem on our side; the microwave relay base station at the entrance is running completely normally, and the antenna power is also at full load. The physical attenuation inside is too severe, and the machine went offline."

President Chen took a deep breath and turned to look at Jiang Lin.

Losing contact at this distance meant that if any accident happened to the machine, there was no room for rescue.

"Engineer Jiang, according to the contingency plan, do we need to send people in immediately with a communication extension cord to find it?" President Chen's voice carried a hint of anxiety.

"No, wait longer." Jiang Lin still stood in front of the screen, arms crossed, completely at ease.

"Wait, wait how long?" President Chen pressed on.

"Three and a half minutes." Jiang Lin glanced at the system local time at the bottom of the screen: "According to its current cruising speed, it should be able to re-enter the next coverage zone within three and a half minutes. If it still hasn't appeared in the field of view of the next signal coverage node after three and a half minutes, you can send people in."

Time passed laborantly second by second in silence.

On the large screen of the console, only the last frozen frame remained.

PG-01 was parked in front of a sludge-covered drainage trough, and the cool-toned light emitted by its front-side perception module shone quietly on a grayish-white concrete wall.

One minute, no data returned.

Two minutes and twenty seconds, the terminal still showed a link timeout.

President Chen began pacing back and forth behind the console.

Old Zhao had silently walked over to the emergency trailer and grabbed the handle.

Three minutes and four seconds.

Suddenly, the on-site read-only terminal let out a crisp beep.

The green indicator light representing data reception began to flash frantically.

The network handshake protocol was re-established.

After a brief burst of snow and tearing, the video image instantly recovered its clarity.

When the picture lit up again, everyone involuntarily let out a low exclamation.

PG-01 did not stay in front of that muddy drainage trough just now.

It had crossed that obstacle and steadily appeared on a brand new, flat section of road 2,240 meters away.

At the same time, the backend data logs began to roll at an extremely high speed.

Those local operation records, photos of instrument high-voltage cabinets, and abnormal temperature difference data from infrared scans accumulated within the more than one hundred meters of communication interruption were being compressed and packaged from the physical recording box inside PG-01's fuselage, and rapidly transmitted back to the console's hard drive.

In this three-minute-and-four-second communication blackout zone, the machine's mission did not pause for even a single second.

It did not pitifully stop in place, waiting for humans to fix the network and retake control of it.

Instead, it completed the posture resolution for crossing the drainage trough in the dark, took photos of three mission points, and continued walking forward.

President Chen stared at the trajectory coordinate points being filled back in, and asked somewhat excitedly: "Engineer Jiang, during the period when the network was disconnected, has it been walking entirely on its own?"

"I said before, the on-site link is responsible for supervision and emergency shutdown, and does not participate in underlying motion control; it fundamentally does not participate in any kinematic control and decision-making logic at the bottom layer of PG-01." Chen Yan explained from the side.

"Then what on earth are we group of people sitting outside, staring at this screen, doing?" President Chen felt an unprecedented impact on his engineering concepts.

"What we are doing is simply watching it." Chen Yan looked at President Chen, his tone calm: "Watching it prove to us in this hell-like environment whether it is qualified to continue walking alone."

President Chen slowly retreated and leaned heavily against the back of the folding chair.

Among all the old robots tested in the past, an extremely conservative piece of code was written into their control logic.

Once communication is interrupted, immediately cut off motor power and stand by in place.

The previous platforms did not have complete local autonomy and could only wait in place after losing contact.

For ground equipment, this is a conservative strategy.

For equipment two kilometers underground, it means maintenance personnel must go in to take over.

PG-01's safety logic is completely opposite to this.

It was born not relying on humans at the entrance to complete every step of decision-making for it.

As long as its own sensor matrix judges that the physical risks ahead have not crossed the fatal boundary set by the core algorithm, and as long as its chassis can find even a single stable footing, it will keep walking in the dark.

It will neither wait nor gamble on luck with humans.

Two thousand eight hundred meters.

Ten twenty-seven in the morning.

After a long trek of more than two hours, PG-01 finally reached the end of the verification section.

Here was a fire compartment door at the end of the verification section.

Hanging next to the door was the complex temperature and humidity integrated instrument panel that needed to be identified at the last mission point.

PG-01 stopped steadily one meter away from the fire door.

The camera gimbal on its back lifted for the last time.

[ Focusing... Scanning... Recognition Complete. ]

It even activated the thermal infrared module to conduct a comprehensive air leakage test on the edge sealing strip of the fire door, and recorded the concentration baseline of harmful gases in the environment into the logs.

The terminal status bar burst out with a neat row of green highlighted information.

[ TASK_PHASE: Arrived at Preset Destination ]

[ Outbound Absolute Distance: 2.80 km ]

[ Outbound Preset Task Point Completion Rate: 47 / 47 (100%) ]

[ Manual Takeover Intervention Count: 0 ]

In the temporary conference room behind the monitoring console, a slight sigh of relief came out.

Several young engineers from the project team couldn't help but gently applaud.

President Chen took a deep breath, picked up the phone on the table, and prepared to dial the number of the group's senior leadership to report this historic breakthrough.

However, amidst this atmosphere filled with the joy of victory, Lao Zhao still remained motionless like a sculpture.

"President Chen, don't rush to make a call to report the good news yet; we're still only halfway there."

President Chen's finger, which had just pressed against the dialing button, froze instantly, and then he slowly put the phone down.

Yes.

Two point eight kilometers was merely proof of the first half.

It only proved that this machine had the ability to walk in alive.

Among the four platforms tested in the past, that southern design—which had violated regulations by opening the rear cover of the control cabin for heat dissipation—had also miraculously reached this 2.8-kilometer finish line marker on the first day.

But what truly determined whether this robot could become an industrial product that customers could actually purchase and work teams could put into daily use was never the outward journey.

Rather, it was whether it could carry the rapidly rising heat generated inside the machine body from long-term high-load operation, carry the chemical battery power that had been nearly half consumed in the battery compartment, and carry the various microscopic mechanical components that had been tormented by the harsh environment of the pipe gallery for more than two hours, walking out of the deep underground nearly three kilometers away from the entrance intact.

Going in was only the beginning.

Coming out was true survival.

After confirming that all outbound task lists were cleared, the PG-01 on the screen began an in-place turn on the concrete ground in front of the fire door, where the width was only thirty centimeters longer than its body.

The six mechanical legs entered a low-speed turning gait.

The foot ends on the left and right sides landed alternately, and the front and rear legs moved sideways in opposite directions with extremely small amplitudes.

Revolving around its own geometric center, it rotated 180 degrees bit by bit.

The front perception module re-aligned with that deep path it had come from.

The return journey officially began.

Eleven-oh-nine.

The return pace seemed heavier than the outward journey.

The multi-channel temperature recorder pushed a yellow warning-level message on the terminal screen.

Xiao Zhang's voice immediately rang out in front of the console, carrying a trace of unsuppressable tremor: "Engineer Jiang, the surface Physics temperature of the shell, the surface Physics temperature of the raw aluminum alloy panels on both sides of the body, has officially exceeded fifty degrees Celsius."

This was the first time since the start of the test that Lao Zhao shifted his attention from the complex mechanical movements to this dry number.

He leaned closer to the screen, looking at the flashing [ 50.4 ℃ ] text.

"It's getting hotter and hotter." Lao Zhao's tone was permeated with a strong sense of worry.

In his simple understanding, if a machine felt so scalding to the touch on the outside, the inside must already be burning up like a big stove.

"Yes, the outside is indeed getting hotter and hotter." Thermal design engineer Xiao Zhang, however, appeared unusually and uncharacteristically calm at this moment.

After experiencing the initial fear, he had completely understood the Physics grand blueprint behind this thermal management system.

"What about the inside? Can the motors and computer boards inside still hold up?" Lao Zhao pressed further.

"The junction temperature of the internal main drive module is currently stable at seventy-six degrees Celsius. And over the past twenty minutes, the slope of the temperature rise curve has been almost zero; it is no longer continuing to heat up." Xiao Zhang pointed to the stable internal red line and explained to Lao Zhao.

Lao Zhao did not have a clear concept of what seventy-six degrees Celsius actually meant in semiconductor Physics.

Deep in his memory, he only clearly remembered that a few months ago, when that old tracked robot broke down due to over-temperature protection and the few of them were desperately dragging it in the dark, he had touched the smooth metal shell of that machine with his hand.

At that time, the shell felt only slightly warm to the touch, and even felt a bit cool under the blowing of the pipe gallery's cold wind.

Yet that ice-cold machine had burned itself to death internally, completely losing all ability to move.

And at this very moment, the PG-01 on the screen was continuing to push forward in the water-filled pipe gallery in an unprecedented high-temperature state.

Unlike traditional electronic products, it did not delicately protect all its components in a constant-temperature greenhouse.

Under the topological structure designed by Jiang Lin, it continuously pumped all the high-density heat flow generated in the internal core area to the armor on both sides of the body.

It transferred the disaster that originally belonged to the inside of the machine to its own hard Physics shell, and then conducted slow and effective passive heat release with the humid air in the pipe gallery through this huge metal structure.

The shell was much hotter than those failed old machines.

But the most critical heart area, in a wonderful thermodynamic balance, did not continue to rise in temperature by even half a degree.

In this extreme temperature gradient, it found its own way of survival.

At 11:46, the PG-01 re-entered the harsh puddle section that was one hundred meters long and had a stagnant water depth of seven centimeters.

The people in front of the console originally thought it would carefully crawl past along the narrow steps at the edge of the drainage ditch like the outward journey.

However, the return path planning of the PG-01 showed a tiny deviation that amazed everyone.

It did not mechanically return along the old footprints it had left behind a few hours ago.

When its front radar scanned that reflective turbid water surface again, the underlying edge computing module quickly recalled the outbound tactile point cloud map stored in the local memory.

During the outbound journey, it had encountered a hidden depression on the right edge that could not be visually confirmed underwater and could only be sensed by the foot torque sensors.

That was a potential vehicle-trapping spot.

This time, two meters away from that underwater depression, the PG-01 naturally adjusted its body yaw angle slightly to the left by less than ten centimeters.

It precisely bypassed the pothole it had felt out with its feet during the outbound journey, chose another more solid and flatter underwater path, and steadily waded through this stagnant water area at a speed ten percent faster than the outbound journey.

This scene did not attract much attention from the people at the scene, because it was just a tiny displacement.

But Lao Zhao saw it clearly.

This old worker who had worked in the underground pipe gallery for half a lifetime, the moment he saw this machine knowing how to avoid harm and seek advantage in the water, turned around silently, stretched out his calloused hands, and forcefully pushed the yellow nylon tow strap placed at the edge of the emergency trailer toward the dark corner by the wall.

He knew that this strap would most likely not be needed today.

At 12:08, the machine crossed the 1.5-kilometer marker line.

At 12:17, the machine steadily crossed the 1.37-kilometer graveyard coordinates.

This time, it was no longer moving further and further away, but was closing in step by step toward the bright entrance with an unstoppable posture.

The terminal panel showed that the remaining Physics power of the body had dropped to near the 34 percent warning line.

But the temperature of the main drive module was still stubbornly pinned at seventy-eight degrees.

All sensor interfaces in the rear task cabin all displayed green lights representing normality.

President Chen's palms were covered in sweat.

He took a deep breath, picked up the walkie-talkie on the table, pressed the call button: "All personnel at the entrance verification line, get ready to welcome it, the PG-01 is back."

Lao Zhao had long been impatient to walk out of the sunshade of the console and stood outside the yellow verification line at the entrance.

Several rows of powerful explosion-proof lights at the top of the pipe gallery cast white light beams all the way to the bend in the deepest part of the tunnel.

Initially, in the dead-silent tunnel, only rhythmic, slight footfall sounds could be heard.

"Tap." Once.

"Tap." Another time.

As the distance shortened, the sound became clearer and heavier.

Finally, that grayish-black body covered with a layer of pipe gallery dust and looking somewhat weathered slowly emerged from behind the last concrete corner two hundred meters away.

The surface of its six mechanical legs was stained with muddy water and black dust, and every time the foot ends landed, they would leave a clear dark rubber mark on the originally dry entrance floor tiles.

It did not suddenly accelerate toward the finish line at the last moment to win applause like heroes in some movies.

Under the underlying control logic, it still maintained the mission cruising speed of the outbound journey.

Even ten meters away from the entrance, it stopped to complete a thermal infrared anomaly scan of the high-voltage cables on the side wall.

Just like that, it walked the last fifty meters of this long journey step by step.

At 12:29.

Accompanied by a long electronic prompt sound emitted by the terminal, the front feet of the PG-01 steadily crossed the yellow verification line at the entrance.

On the big screen of the console, after a few seconds of background processing, the settlement data dominated the center of the entire screen in an overbearing posture.

[ FINAL _ REPORT: Underground Pipe Gallery Field Limit Verification Ended ]

[ Total Cumulative Operating Mileage: 5.63 km ]

[ Full System Continuous Loaded Operating Time: 4h17min ]

[ Preset Task Point Completion Rate: 47 / 47 ( 100% ) ]

[ Number of Manual Takeovers and Remote Interventions: 0 ]

[ Number of Hardware Over-temperature Protection Triggers: 0 ]

[ Safety State Machine Autonomous Retreat: Not Triggered ]

[ Task Status: Completed ]

The PG-01 stopped steadily in front of the black transport case.

The joint drives were gradually unloaded, and the entire grayish-black body sank downward.

The six muddy mechanical legs retracted inward, returning to their initial dormant posture.

The indicator light of the rear task cabin changed from green back to standby blue.

President Chen silently stood up from his chair and strode over to the robot that had just completed the off-roading.

He did not mind the dirty muddy water on the surface of the machine, squatted down directly, and gently stroked the still-scalding aluminum alloy shell armor with his hand.

He did not turn his head to ask Jiang Lin how the gait control algorithm that amazed him was written, nor did he ask what kind of thermal conductive materials were used for the heat flow routing structure inside the control cabin.

He stood up and looked enthusiastically at Liang Zhixia standing to the side: "Director Liang, how much does this machine actually sell for?"

Liang Zhixia's face maintained its usual calmness and composure.

She pulled out from the black briefcase she carried a standardized procurement scope list that had been prepared several days ago but had never been taken out.

She handed the list to President Chen: "President Chen, this is an engineering verification machine with a large amount of experimental nature. Low Entropy Workshop has clear commercial principles; we do not sell this kind of bare-machine prototype to any industrial customers individually. Because this cannot guarantee its long-term stability in your business workflow."

President Chen took the list and quickly scanned the entries on it: "Then how many additional edge systems do we need to buy to make it run?"

"A complete closed-loop system." Liang Zhixia swept the tip of her pen across the list, "including the task scheduling terminal server deployed privately based on your internal network environment, a set of PB-level local on-site data archiving and analysis software, hardware spare parts packages including vulnerable parts, two weeks of operation and emergency training for your on-site maintenance teams, and one year of on-site technical support and major failure response service."

"We want five for the first batch." President Chen did not bargain and directly threw out the quantity.

Liang Zhixia's eyes flickered slightly, she closed the pen cap, and looked at President Chen: "If I remember correctly, in our previous communication, the original plan submitted by your group was to first purchase three units for trial use on different road sections."

"Plans are made to be broken."

President Chen waved his hand broadly and pointed to the deep pipe gallery in the distance: "Before today, three units were indeed enough, because we thought this thing was just a slightly advanced toy, and three units could only be used to take turns repairing each other within a team. But after watching these 5.6 kilometers today, I've changed my mind. Five units are just enough to completely cover the all-weather inspection and scheduling needs of two major maintenance teams in our district. I don't want to let Lao Zhao and the others wear anti-static suits to wade in the water every day anymore."

President Chen turned around and pointed to the square task cabin on the back of the PG-01: "In addition, Director Liang. If this rear task module is Physics replaceable, in subsequent purchases, we will also need to add separate ultrasonic detection modules for local discharge of high-voltage cables from you, as well as high-precision acoustic acquisition arrays capable of identifying abnormal sounds of water pumps."

"These can enter the joint evaluation cycle of the second batch of modules as added items." Liang Zhixia controlled the requirement creep neither humbly nor arrogantly, "but in the delivery order of the first batch, Low Entropy Workshop, to ensure the stability of the basic chassis, does not accept any temporarily added non-standard hardware requirements. We must guarantee the delivery quality."

President Chen nodded, expressing approval of this rigorous attitude: "Understandable. What about the delivery cycle?"

"After receiving the advance payment, the first delivery machine will be delivered to your site within sixty days. All five units will be completely produced and completed factory final inspection and delivery within a time not exceeding ninety days."