Material handling system

Abstract

The application provides a material handling system, comprising: a reference oscillator for generating a global coupling field covering a working area; a plurality of phase-shifted beacons arranged at each material demand point, each phase-shifted beacon comprising a circuit for receiving the global coupling field, and performing phase shift processing and re-radiation based on a preset characteristic phase shift; and a plurality of handling robots, each handling robot comprising: a lockable oscillator for synchronizing with the global coupling field; a phase comparator electrically connected to the lockable oscillator, the phase comparator being configured to detect a real-time phase difference between the lockable oscillator and the received phase-shifted beacon radiation field; a direction decision module electrically connected to the phase comparator, the direction decision module being configured to determine a spatial direction in which the phase difference decreases most rapidly; and a motion controller, the motion controller being configured to drive the robot to move according to the phase difference and the direction determined by the direction decision module. The application is suitable for low-cost material handling in complex environments.

Description

Technical Field

[0001] This invention belongs to the field of material handling and robot control technology, and specifically relates to a material handling system. Background Technology

[0002] With the development of industrial technology, automated material handling systems have been widely used in warehousing, logistics, and manufacturing. Existing navigation technologies for material handling robots mainly include: laser SLAM, visual navigation, magnetic strip / QR code guidance, or centralized scheduling systems. These technologies have the following drawbacks: First, they are costly. LiDAR, high-performance controllers, and communication infrastructure are expensive, resulting in large initial investments and making them unsuitable for small and medium-sized enterprises. Second, they rely heavily on communication. Robots need a stable wireless network and a central scheduler to perform tasks, which poses a risk of single points of failure and communication delays. Communication interruptions can lead to system paralysis. Furthermore, existing technologies have poor environmental adaptability. In GPS-denied environments, as well as low-light and dusty environments, visual and laser sensors are susceptible to interference, reducing navigation reliability. Finally, the deployment of existing technologies is complex, requiring pre-mapping, laying magnetic strips / QR codes, or installing numerous beacons. Deployment cycles are long, maintenance costs are high, and they are difficult to adapt to dynamically changing operating environments.

[0003] In addition, existing technologies also utilize electromagnetic field phase differences for positioning (such as RFID phase difference ranging and pseudo-satellite carrier phase difference technology). However, these methods are usually limited to static positioning or single-point direction finding, that is, calculating the robot's absolute coordinates or distance by measuring the phase difference, and then combining it with path planning algorithms to achieve navigation. Essentially, it still follows the traditional paradigm of "localization first, planning later," requiring the robot to calculate its own position in real time and relying on maps or a central scheduling system. This approach also suffers from drawbacks such as high cost, reliance on prior maps and calibration, susceptibility to interference, and the need for central scheduling or communication.

[0004] Therefore, there is an urgent need for a low-cost, flexible, communication-independent, and environmentally adaptable material handling control method and system. Summary of the Invention

[0005] In view of the above-mentioned shortcomings in the prior art, the present invention provides a material handling system to solve the problems in the background art.

[0006] This invention provides a material handling system, comprising: a reference oscillation source for generating a global coupled field covering the work area; multiple phase-shifting beacons, respectively arranged at various material demand points, each phase-shifting beacon including circuitry for receiving the global coupled field, performing phase-shifting processing based on a preset characteristic phase offset, and re-radiating; multiple handling robots, each handling robot including: a lockable oscillator for synchronizing with the global coupled field; a phase comparator electrically connected to the lockable oscillator, the phase comparator being used to detect the real-time phase difference between its own oscillator and the received phase-shifting beacon radiation field; a direction decision module electrically connected to the phase comparator, the direction decision module being used to determine the spatial direction in which the phase difference decreases the fastest; and a motion controller electrically connected to both the phase comparator and the direction decision module, the motion controller being used to drive the robot to move according to the phase difference and the direction determined by the direction decision module.

[0007] In one specific embodiment of the present invention, the direction decision module calculates the phase gradient by measuring the field phase change rate in different directions using multiple sets of orthogonal loop antennas, or learns the gradient direction online by controlling the robot to make small displacements and comparing the phase difference changes before and after the displacement.

[0008] In one specific embodiment of the present invention, the global coupling field is generated by radiation from at least three frequency-locked and phase-locked reference oscillators, which maintain a phase difference of less than a preset angle between each other through a wired synchronization cable or a wireless synchronization protocol.

[0009] In one specific embodiment of the present invention, the transport robot further includes an environmental perception module, which is electrically connected to the motion controller. The environmental perception module is used to detect changes in the surrounding environment and send an obstacle avoidance signal to the motion controller based on the changes in the physical characteristics of the global coupled field to trigger an obstacle avoidance response.

[0010] In one specific embodiment of the present invention, the handling robot further includes an end-effector precision positioning sensor, which is electrically connected to the phase comparator and the motion controller respectively. The end-effector precision positioning sensor includes one or more of a vision sensor, a laser rangefinder, and a mechanical contact sensor. When the real-time phase difference is less than the preset threshold, the handling robot switches to the end-effector precision positioning mode and is guided by the end-effector precision positioning sensor to complete the final alignment.

[0011] In one specific embodiment of the present invention, the lockable oscillator is a second-order phase-locked loop circuit, and the handling robot further includes a receiving antenna and a low-noise amplifier. The robot receives a global coupled field signal through the receiving antenna, and the low-noise amplifier is used to amplify the global coupled field signal. The amplified global coupled field signal serves as the reference input of the second-order phase-locked loop circuit.

[0012] In one specific embodiment of the present invention, the second-order phase-locked loop circuit includes a phase detector, a loop filter, and a voltage-controlled oscillator (VCO). The phase detector compares the phase difference between a reference signal and a feedback signal from the VCO to generate an error voltage. After passing through the loop filter, the frequency of the VCO is adjusted so that the output frequency of the VCO gradually approaches the reference frequency. When the frequency of the VCO is equal to the reference frequency and the phase difference is constant, the second-order phase-locked loop circuit enters a locked state.

[0013] In one specific embodiment of the present invention, the difference between the output frequency of the robot's internal oscillator and the global coupling field frequency is less than ±10ppm, which is determined to be frequency lock.

[0014] In one specific embodiment of the present invention, after the robot is powered on, it executes the following process: the receiving antenna scans the direction of the strongest signal and adjusts the receiving gain to make the signal amplitude appropriate; the received signal is used as a reference input, the initial frequency of the voltage-controlled oscillator is set to the nominal value, and the loop is closed; the lock indicator signal is monitored, and if the lock is not locked within a preset time, the receiving antenna direction or gain is adjusted and the test is retried; if the test fails after multiple retries, a fault alarm signal is output.

[0015] In one specific embodiment of the present invention, during operation, the phase comparator continuously monitors the phase difference between its own oscillator and the receiving field; if the phase difference changes abruptly by more than 30° and lasts for more than 1 second, it is determined that the lock has been lost, the robot stops moving, and the synchronization process is re-executed.

[0016] Therefore, this invention utilizes a global coupled field to achieve frequency locking and synchronization across the entire cluster. By directly driving robot movement through the phase gradient of the physical field, it eliminates dependence on a central server and wireless communication links. Even in extreme cases of network interruption or server downtime, the robot can still operate autonomously based on the physical characteristics of the environmental field, significantly reducing the risk of single-point failure. Furthermore, this invention integrates complex path planning into the environmental field; the robot only needs to detect the phase difference using a simple phase comparator to determine its direction of movement. This "lightweight" onboard architecture eliminates the need for expensive LiDAR and high-performance industrial control computers, significantly reducing single-machine hardware costs and power consumption, and significantly extending the device's runtime. Moreover, this invention dynamically corrects the phase difference detected in real time by constructing a distortion compensation model between the theoretical and actual phases. This mechanism effectively overcomes phase drift caused by multipath effects and environmental interference, ensuring navigation stability and accuracy in high-reflectivity environments such as semiconductor factories and metal warehouses. Simultaneously, by setting up an environmental perception module, it achieves passive obstacle avoidance without communication, further improving the robot's operational safety and environmental adaptability. Attached Figure Description

[0017] Figure 1 This is a module connection diagram of a material handling system provided in an embodiment of the present invention.

[0018] Figure 2 for Figure 1 Module connection diagram of the transport robot.

[0019] Figure 3 This is a flowchart of a material handling control method provided in an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments described in the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0021] See Figure 1This invention provides a material handling system 10, which can be, for example, an automated material handling system for a semiconductor cleanroom, an automated material handling system for industrial warehousing, a flexible material handling system for a production workshop, or an indoor material handling system, etc., and is not specifically limited here. The material handling system 10 includes, for example, a reference oscillation source 100, multiple phase-shift beacons 200, and multiple handling robots 300. The reference oscillation source 100 is deployed at a preset location in the work area, the multiple phase-shift beacons 200 are respectively arranged at various material demand points in the work area, and the multiple handling robots 300 (or unmanned overhead cranes) are distributed in the work area to perform material handling tasks.

[0022] A reference oscillator 100 is used to generate a global coupled field covering the work area. To establish a global coupled field within the work area, at least one reference oscillator 100 is required as the generator. Preferably, for large areas, multiple interlocked phase reference oscillators 100 are used, connected to the same clock reference via a wired synchronization cable to achieve frequency locking and phase interlocking. By adjusting the phase offset of each source, waves from the four sources are superimposed in phase (phase difference less than 3°) at the geometric center of the work area, thereby forming a global coupled field with uniform energy distribution and a smooth phase gradient.

[0023] This embodiment uses a reference oscillator 100 as an example to illustrate its structure and layout. The reference oscillator 100 may include, for example, a frequency synthesizer, a power amplifier, and an omnidirectional transmitting antenna. The frequency synthesizer, for example, uses a phase-locked loop (PLL) frequency synthesizer or a direct digital synthesizer (DDS) to generate a continuous wave signal. This frequency belongs to the ISM (Industrial, Scientific and Medical) band, requires no license, and has a suitable wavelength, facilitating antenna design. The power amplifier, for example, amplifies the output power of the frequency synthesizer to a preset value, ensuring that the field strength at any point in the operating area is not lower than a preset threshold. The transmitting antenna, for example, uses an omnidirectional antenna with vertical polarization, so that the field uniformly covers the entire area.

[0024] Multiple phase-shifting beacons 200 are installed at each material demand point. Each phase-shifting beacon 200 includes, for example, circuitry for receiving the global coupled field, performing phase-shifting processing based on a preset characteristic phase offset, and re-radiating the signal. This circuitry may include, for example, a receiving antenna, a programmable phase shifter, a microcontroller unit (MCU), and a re-radiating antenna. The output of the receiving antenna is electrically connected to the input of the programmable phase shifter, the control terminal of the programmable phase shifter is electrically connected to the microcontroller, and the output of the programmable phase shifter is electrically connected to the input of the re-radiating antenna. The receiving antenna is used to capture the global coupled field signal within the work area; the programmable phase shifter, for example, employs a PIN diode-based phase-shifting network, enabling phase shifting in 1° increments within a 0–360° range, for performing phase-shifting processing on the received global coupled field signal; the microcontroller loads a preset characteristic phase offset onto the programmable phase shifter via a control voltage or digital interface; and the re-radiating antenna is used to re-radiate the phase-shifted signal to a local area.

[0025] See Figure 2 The handling robot 300 may include, for example, a lockable oscillator 310, a phase comparator 320, a direction decision module 330, and a motion controller 340. The lockable oscillator 310 is electrically connected to the phase comparator 320, which is electrically connected to both the direction decision module 330 and the motion controller 340. The direction decision module 330 is also electrically connected to the motion controller 340. The handling robot 300 is used to autonomously move to the material demand point based on the global coupled field and the radiation field of the phase-shifting beacon 200.

[0026] like Figure 2 As shown, the lockable oscillator 310 is used to achieve frequency locking and phase synchronization with the global coupled field. The lockable oscillator 310 can be, for example, a second-order phase-locked loop (PLL) circuit, which includes, for example, a phase detector (PD), a loop filter (LF), and a voltage-controlled oscillator (VCO). The phase detector is used for phase comparison and outputs a voltage proportional to the phase difference; the loop filter is used to filter out high-frequency components and control the dynamic response of the PLL; the VCO outputs an oscillation signal whose frequency is adjusted by the control voltage. Based on the cooperation of these components, the lockable oscillator 310 achieves frequency locking and phase synchronization with the global coupled field by detecting the phase difference and adjusting the output frequency.

[0027] like Figure 2As shown, phase comparator 320 is used to detect the real-time phase difference between the current phase of the lockable oscillator 310 and the received radiation field of the phase-shifting beacon 200. Phase comparator 320 can, for example, employ an integrated phase detection chip, which receives two input signals: a reference signal from its own oscillator (PLL output) and a signal from the received radiation field of the phase-shifting beacon 200, and outputs a voltage signal proportional to the phase difference between the two. During operation, phase comparator 320 continuously monitors the phase difference between its own oscillator and the received field. If the phase difference abruptly exceeds a preset threshold, it determines that the lock has been lost, the robot stops moving, and the synchronization process is re-executed.

[0028] like Figure 2 As shown, the direction decision module 330 is used to determine the spatial direction in which the phase difference decreases the fastest. The direction decision module 330 can calculate the phase gradient, for example, by measuring the rate of change of the field phase in different directions using multiple sets of orthogonal antennas, or by controlling the handling robot 300 to perform small displacement probes and comparing the phase difference change before and after the displacement to learn the gradient direction online.

[0029] like Figure 2 As shown, the motion controller 340 drives the handling robot 300 to move according to the phase difference and the direction determined by the direction decision module 330. The motion controller 340 can, for example, employ a motor drive controller with an encoder, enabling the robot to move autonomously along the direction of decreasing phase difference until it reaches the material demand point.

[0030] In this embodiment of the invention, the reference oscillator 100 generates a global coupled field covering the entire work area, providing a unified phase reference for the system. The handling robot 300 entering the work area achieves frequency locking and phase synchronization with the global coupled field through its internal lockable oscillator 310. When there is a material handling requirement, the phase-shifting beacon 200 placed at the target material demand point receives the global coupled field signal. After the microcontroller loads a preset characteristic phase offset, the programmable phase shifter completes the phase shifting process, and then the phase-shifted signal is radiated to the local area through the re-radiating antenna. The handling robot 300 detects the phase difference between its own oscillator and the radiation field of the phase-shifting beacon 200 in real time through the phase comparator 320. The direction decision module 330 determines the spatial direction in which the phase difference decreases the fastest. Finally, the motion controller 340 drives the robot to move autonomously according to the magnitude of the phase difference and the determined direction until it reaches the material demand point.

[0031] Therefore, the material handling system 10 provided in this embodiment of the invention, by setting up a reference oscillation source 100, a phase-shifting beacon 200 and a handling robot 300, and by leveraging the phase gradient characteristics of the global coupled field and the coordinated cooperation of each component, achieves fully automated material handling operations. It not only eliminates the dependence on maps, GPS and central dispatching systems, solving the problems of high single-point failure risk and strong communication dependence in traditional solutions, but also eliminates the need for expensive lidar and high-computing-power controllers, significantly reducing system hardware costs and deployment difficulty, while improving operational reliability and adaptability in complex industrial environments, and meeting the needs of modern material handling.

[0032] Furthermore, the global coupling field is generated by radiation from at least three frequency-locked and phase-locked reference oscillators 100. The reference oscillators 100 maintain a phase difference of less than a preset angle with each other via a wired synchronization cable or a wireless synchronization protocol. For large-area operating areas, at least three reference oscillators 100 can be deployed collaboratively, for example, with all reference oscillators 100 connected to the same clock reference via a wired synchronization cable or frequency-locked and phase-locked via a wireless synchronization protocol, ensuring that the phase difference between any two reference oscillators 100 is less than a preset angle. Through the coherent superposition of multiple reference oscillators 100, a global coupling field with uniform energy distribution and smooth phase gradient can be formed over a larger area, ensuring the navigation stability of the system in large-area operating areas. In other embodiments, the number and deployment positions of the reference oscillators 100 can be flexibly adjusted according to the actual application scenario; this embodiment of the invention is not limited thereto.

[0033] Furthermore, the handling robot 300 also includes an environmental perception module 350. The environmental perception module 350 detects changes in the surrounding environment and sends an obstacle avoidance signal to the motion controller 340 based on changes in the physical characteristics of the global coupled field to trigger an obstacle avoidance response, further improving the robot's operational safety and environmental adaptability. The environmental perception module 350 shares a receiving antenna and a low-noise amplifier (LNA) with the phase comparator 320, and is also electrically connected to the motion controller 340.

[0034] The environment perception module 350 can sense surrounding obstacles, for example, by detecting the phase change of the global coupled field. When an obstacle approaches, causing reflection and scattering of the global coupled field and resulting in phase distortion, the environment perception module 350 detects that the distortion exceeds a preset threshold and then sends an obstacle avoidance signal to the motion controller 340 to trigger an obstacle avoidance response. Through the above settings, passive obstacle avoidance without communication can be achieved, improving the safety of robot operation.

[0035] Furthermore, the handling robot 300 also includes an end-effector precision positioning sensor 360, which may include one or more of a vision sensor, a laser rangefinder, and a mechanical contact sensor. When the real-time phase difference is less than the preset threshold, the handling robot 300 switches to end-effector precision positioning mode, and the end-effector precision positioning sensor 360 guides the final alignment. The end-effector precision positioning sensor 360 is electrically connected to, for example, a phase comparator 320, and also electrically connected to a motion controller 340. The end-effector precision positioning sensor 360 may, for example, employ a low-resolution vision camera paired with an infrared laser rangefinder. When the phase comparator 320 detects that the real-time phase difference is less than the preset threshold, it triggers the end-effector precision positioning sensor 360 to operate, outputting a precise positioning signal to control the motion controller 340 to complete the final alignment. Through the above settings, the end-effector positioning accuracy of material handling can be effectively improved.

[0036] See Figure 3 This invention also provides a material handling control method, which can be applied, for example, to the material handling system 10 described above. The material handling control method provided by this invention mainly includes the following steps: Step S1: A global coupling field is established by a reference oscillation source within the work area, and the internal oscillator of the handling robot located within the work area is frequency locked and phase synchronized using the global coupling field; Step S2: The phase-shifting beacon at the target material demand point receives the global coupled field, performs phase-shifting processing on the global coupled field using a preset characteristic phase offset, and re-radiates the phase-shifted signal to the local area; Step S3: The handling robot detects the real-time phase difference between the current phase of its internal oscillator and the field phase radiated by the phase-shifting beacon, and moves autonomously along the spatial direction in which the phase difference decreases until the phase difference is less than a preset threshold, so that the handling robot reaches the location of the material demand point.

[0037] This invention establishes a global coupling field by deploying a reference oscillation source within the work area. This global coupling field enables the internal oscillator of the handling robot to achieve frequency locking and phase synchronization, providing a unified and stable phase reference for the entire system and accurate basic data support for subsequent phase difference detection and navigation. Furthermore, by placing a phase-shifting beacon at the target material demand point, the beacon receives the global coupling field, performs a characteristic phase shift, and then re-radiates, transforming the material demand point into a detectable physical signal for the robot. This enables precise identification of the target point and differentiation of different operation types, providing clear target guidance for robot navigation. The handling robot detects the phase difference between its own oscillator and the phase-shifting beacon's radiated field in real time and moves autonomously along the spatial direction where the phase difference decreases. This transforms complex path planning logic into a phase gradient distribution of the physical field, eliminating the need for the robot to calculate its own coordinates or pre-plan a path, enabling autonomous navigation to the target point. Through these steps, this invention effectively eliminates reliance on maps, GPS, and central scheduling, significantly reducing system hardware costs and deployment difficulty, while improving system reliability and environmental adaptability, making it suitable for material handling needs in various industrial scenarios.

[0038] Furthermore, the global coupling field is an electromagnetic field, an acoustic field, or a mechanical vibration field; the characteristic phase offset is a fixed angular offset relative to the received phase of the global coupling field at the phase-shifting beacon, with different phase offsets corresponding to different material handling types. The global coupling field can, for example, be an electromagnetic field in a commonly used industrial frequency band, or an ultrasonic field or mechanical vibration field; the characteristic phase offset can, for example, be pre-set with different fixed angular offsets corresponding to different material handling types, and this mapping relationship can be pre-stored in the memory of the handling robot. Through the above settings, precise identification of target points and differentiation of different material handling types can be achieved, enabling the robot to automatically execute corresponding operations based on the detected phase offset.

[0039] Furthermore, the moving speed of the transport robot is positively correlated with the detected phase difference. When the phase difference is less than the preset threshold, the transport robot switches to end-effector precision positioning mode and releases the lock between its own oscillator and the global coupling field after completing the material handling. The moving speed of the transport robot can be proportionally controlled according to the phase difference, for example, using a segmented speed adjustment strategy. After completing the material handling, the lock can be released, for example, by disconnecting the oscillator reference input signal. Through the above settings, the efficiency of long-distance navigation is ensured, the accuracy of short-distance positioning is improved, and interference with subsequent robots after the operation is completed is avoided.

[0040] Furthermore, an offline field calibration step is included before step S3. The offline field calibration step is performed before the handling robot moves autonomously along the direction of decreasing phase difference. The offline field calibration step includes: collecting the theoretical phase and actual measured phase of the global coupled field of multiple spatial points in the work area, and generating a distortion compensation parameter table or compensation function. During the movement, the handling robot queries the distortion compensation parameter table or calls the compensation function according to its own position to correct the detected real-time phase difference.

[0041] The offline field calibration can, for example, employ a calibration robot carrying a phase measuring instrument. The robot traverses the entire work area at a preset grid spacing, recording the theoretical and actual measured phases at each grid point. Compensation values ​​are calculated, and a compensation parameter table is generated. After calibration, the compensation parameter table is sent to all handling robots. In actual work scenarios, multipath effects can easily interfere with phase detection. It should be noted that multipath effects refer to the interference caused by radio waves propagating through multiple transmission paths, leading to phase distortion and signal fading in the received field, which affects navigation accuracy. The above calibration settings can effectively overcome phase drift caused by multipath effects and environmental interference, ensuring navigation stability and accuracy in complex environments.

[0042] In different embodiments, the "global coupled field" described in this invention refers to a steady-state field formed by the interference and superposition of coherent waves radiated by at least three spatially distributed reference oscillation sources within the working space. This field is characterized by the phase distribution of the field at any location within the working area. (x,y) has a monotonic mapping relationship with spatial coordinates (x,y) (i.e., the phase value changes monotonically with the distance from the target point), thus providing a physical basis for phase difference navigation.

[0043] In one specific embodiment of the present invention, the frequency synthesizer of the reference oscillator generates a continuous wave signal with a frequency of 2.4 GHz, which belongs to the ISM band and has a wavelength of about 12.5 cm; the power amplifier amplifies the output power of the frequency synthesizer to 15 dBm, ensuring that the field strength at any point in the 50 m × 50 m area is not lower than -70 dBm.

[0044] In one specific embodiment of the invention, each handling robot may contain at least one lockable oscillator, specifically a second-order phase-locked loop (PLL) circuit. The PLL circuit includes a phase detector (PD), a loop filter (LF), and a voltage-controlled oscillator (VCO). The VCO outputs an oscillator whose frequency is regulated by a control voltage, and its center frequency is the same as the global coupling field frequency (2.4 GHz).

[0045] The robot receives the global coupled field signal via a receiving antenna, which is then amplified by a low-noise amplifier (LNA) and used as the reference input for the PLL circuit. The PLL locking process is as follows: (1) Initial state: VCO oscillates freely with a frequency close to 2.4 GHz.

[0046] (2) Acquisition stage: The phase detector compares the phase difference between the reference signal and the VCO feedback signal, generates an error voltage, and adjusts the VCO frequency after passing through the loop filter so that it gradually approaches the reference frequency.

[0047] (3) Locking Phase: When the VCO frequency is equal to the reference frequency and the phase difference is constant (usually 0° or a fixed value), the PLL enters the locked state. After locking, the output signal of the robot's internal oscillator has the same frequency and phase synchronization with the received global coupled field signal.

[0048] In a specific embodiment, the PLL parameters are set as follows: loop bandwidth of 100Hz, acquisition range of ±10MHz, lock-on time of less than 200ms, and phase error after lock-on of less than 5°. When the robot moves, the receiving frequency will shift slightly due to the Doppler effect. The tracking bandwidth of the PLL should be able to cover the frequency shift caused by the maximum relative velocity, thereby maintaining lock-on.

[0049] In one specific embodiment of the present invention, if the difference between the output frequency of the robot's internal oscillator and the global coupled field frequency is less than ±10ppm, it is considered frequency locked. The instantaneous phase difference between the phase of the robot's own oscillator and the phase of the received field is detected; if this difference is within a preset tolerance range and does not drift linearly over time, it is considered phase synchronized. In actual implementation, the PLL's lock indication signal can be used to determine whether synchronization is achieved.

[0050] In one specific embodiment of the present invention, after the robot is powered on, the following process is executed: (1) Scan the global coupling field: The receiving antenna scans the direction of the strongest signal and adjusts the receiving gain to make the signal amplitude appropriate.

[0051] (2) Start PLL: Use the received signal as the reference input, set the VCO initial frequency to the nominal value, and close the loop.

[0052] (3) Waiting for lock: Monitor the lock indication signal. If the lock is not locked within the preset time (e.g., 200ms), adjust the direction or gain of the receiving antenna and try again. If the retries fail multiple times (e.g., three times), report to the central system.

[0053] During operation, the phase comparator continuously monitors the phase difference between its own oscillator and the receiving field. If the phase difference suddenly changes by more than 30° and lasts for more than 1 second, it is determined that the lock has been lost, the robot stops moving, and the synchronization process is re-executed.

[0054] In one specific embodiment of the present invention, in a scenario where multiple handling robots are operating concurrently, to prevent mutual interference between robots on the global coupled field, the present invention achieves obstacle avoidance without communication through an environmental perception mechanism, specifically employing the following measures: (1) Environmental perception and physical characteristic modulation: Since the body of a handling robot is usually composed of a metal frame, motors and electronic components, these media will produce reflection, scattering or refraction effects on the incident global coupled field, thereby causing changes in the physical characteristics of the local field (such as phase, amplitude or spectral distribution). This invention utilizes this physical phenomenon to use the modulation effect of the robot body on the field as a signal source for perceiving the surrounding environment.

[0055] (2) Interference suppression strategy: Each robot's oscillator is only used to lock the phase of the global coupled field and does not actively radiate signals of the same frequency to the outside, thus avoiding mutual interference among multiple robots. In dense areas, the robot can further reduce mutual interference by briefly cutting off the influence of its own oscillator on the surrounding field and receiving signals in a time-division manner.

[0056] (3) Obstacle avoidance response: The robot's built-in environmental perception module monitors the changes in the above physical characteristics in real time through its signal conditioning unit (band-stop filter). When the detected change exceeds a preset second threshold, the system determines that there is an obstacle (other robot) in the vicinity and automatically triggers an obstacle avoidance response.

[0057] In one specific embodiment of the present invention, when no task is received, the phase-shifting beacon is in a low-power sleep mode, maintaining only the reception of the global coupled field. During this mode, no phase-shifting processing or re-radiation is performed on the signal to avoid unnecessary interference to the global field. The central control system sends an operation command (such as "pick up goods") to the phase-shifting beacon at the target material demand point. The MCU wakes up the phase shifter and loads a preset characteristic phase offset according to the command. The beacon receiving antenna captures the global coupled field signal, which is amplified by an LNA and then fed into a phase shifter. The phase shifter shifts the phase of the input signal. The output signal phase is The signal is then amplified by a power amplifier and radiated through a re-radiating antenna to a localized area (approximately 1.5 meters in radius). Once the handling robot completes its operation and reports to the central system, the central system sends a reset command to the beacon, clearing the offset and resuming its dormant listening state.

[0058] The characteristic phase offset described in this invention is a fixed angle offset. For each predefined material operation type, there is a corresponding fixed phase offset value. Throughout the entire execution cycle of a single task, the phase shift beacon loads this phase offset value and maintains it unchanged until the task is completed and reset. Different fixed phase offsets... Corresponding to different material handling types, for example: +90°: pick up goods; -90°: place goods; +45°: charge; -45°: wait / standby; 180°: emergency stop.

[0059] This mapping relationship can be pre-stored in the robot's memory. After detecting a phase difference change, the robot identifies the phase difference between its locked phase and the received field phase. This allows the corresponding operations to be performed.

[0060] In one specific embodiment of the invention, the phase comparator in the robot receives two input signals: a reference signal from its own oscillator (PLL output) and a signal from the received phase-shifting beacon radiation field. The phase comparator outputs a voltage signal proportional to the phase difference between the two signals (0~1.8V corresponds to 0~180°).

[0061] The direction decision module is used to determine the spatial direction of the fastest phase difference decrease (i.e., the phase gradient direction). The following is a detailed implementation of the direction decision module: The robot is equipped with three orthogonal loop antennas to measure the rate of change of the field phase in the X, Y, and Z directions. Through vector synthesis, the spatial phase gradient direction can be directly calculated in real time without the robot needing to move.

[0062] The small displacement trial-and-error method involves the robot first moving a tiny 1cm along its current direction of travel and comparing the phase difference before and after the movement. If the phase difference decreases, the robot maintains its direction; if it increases, it deflects a small angle (e.g., 10°) to the left or right and tries again. Through multiple trials, the robot gradually approaches the gradient descent direction. In the specific implementation, the robot performs a trial every 100ms, and the step size is adaptively adjusted according to the current speed (larger step size at high speeds and smaller step size at low speeds).

[0063] In one specific embodiment of the present invention, the motion controller is based on the formula... Control movement speed, where This is a proportionality coefficient (0.1 m / (s·°) in this embodiment). Phase difference (unit: degrees).

[0064] To achieve better control performance, piecewise functions can be used: when When the angle is greater than 30°, v = 1 m / s (maximum speed); when the angle is less than or equal to 10°, v = 1 m / s (maximum speed). When the angle is ≤30°, v=0.0333· m / s (linear region); when When the angle is less than 10°, v = 0.1 m / s (low-speed fine search).

[0065] During robot movement, its built-in environmental perception module monitors changes in the physical properties of the global coupled field in real time. In this embodiment, as a preferred implementation, the environmental perception module achieves obstacle avoidance by detecting changes in phase: because the robot body is a metallic medium, it reflects and scatters incident electromagnetic waves, causing detectable distortions in the phase distribution of the local field. Let the real-time phase detected by robot A be... When another robot B approaches, the field phase at point A will shift. .

[0066] Because the body of the handling robot can be made of a metal frame, it will reflect and scatter the incident electromagnetic waves, causing a shift in the phase distribution of the local field. Let the phase of the incident field detected by robot A in real time be... The total field phase including the reflected wave is .

[0067] The environmental perception module calculates near-field phase distortion (i.e., changes in physical properties):

[0068] The change It is inversely proportional to the square of the distance d from the obstacle, i.e. .

[0069] The system has preset obstacle avoidance thresholds: =0.1rad (This value is set based on a robot radius of 0.5m and a safety distance of 0.5m).

[0070] When the environment perception module detects Greater than or equal to When an obstacle is detected approaching, an obstacle avoidance response is triggered.

[0071] The obstacle avoidance control module generates a repulsive velocity component perpendicular to the current phase gradient direction. :

[0072] in, The repulsion gain coefficient is taken as 0.2 m / (s·rad) This is a unit vector perpendicular to the current gradient direction. The motion controller will navigate the speed. With repulsion velocity Vector composition yields the final velocity. .

[0073] when When the obstacle is determined to be far away, the repulsion component is removed, and the robot resumes pure phase gradient navigation mode.

[0074] When the detected real-time phase difference is less than the preset threshold, the robot determines that it has reached the vicinity of the target point. At this time, it stops navigation based on the global coupled field, switches to the end-effector precision positioning mode, and completes the final material handling operation.

[0075] After completing the material handling, the robot briefly disconnects the PLL's reference input signal for approximately 0.5 seconds to allow the oscillator to enter free oscillation mode, and then recloses the loop to restore lock. During unlocking, the phase-shift beacon no longer detects the robot's presence, and its re-radiated field returns to the default phase (i.e., no offset state), avoiding interference with subsequent robots.

[0076] In one specific embodiment of the present invention, 10 handling robots are used. Taking one of them at the starting position (10, 10) as an example, the robot includes: a lockable oscillator: a second-order PLL with a center frequency of 2.4 GHz, a loop bandwidth of 100 Hz, and a locking time of <200 ms. Receiving antenna: It adopts a composite antenna design, including a vertically polarized omnidirectional antenna for electric field reception (used by the phase comparator and environmental sensing module) and a triorthogonal loop antenna for magnetic field induction (used by the direction decision module). Phase comparator: AD8302 phase detection chip, outputting 0~1.8V corresponding to a phase difference of 0~180°; Direction decision module: Three orthogonal loop antennas (three mutually perpendicular magnetic rings) can measure the field phase change rate in the X, Y, and Z directions in real time and directly calculate the phase gradient direction without the need for trial movement; Motion controller: DC servo motor + encoder, controls wheel speed according to speed command, speed command refresh rate 10Hz, maximum speed 1m / s; Environmental perception module: Signal receiving front end: Shares receiving antenna and low noise amplifier (LNA) with phase comparator to reduce hardware cost and system complexity; Signal conditioning unit: Includes band-stop filter, which is configured to filter out the main frequency signal of phase shift beacon (i.e. f0=2.4GHz) and extract only broadband phase noise or harmonic components caused by other robots.

[0077] End-efficiency positioning sensors: a low-resolution vision camera (for identifying AprilTags (visual reference marking system)) and an infrared laser rangefinder (accuracy ±1mm); Communication module: Low-power WiFi (Wireless Fidelity) technology, used to receive task instructions and compensation table updates.

[0078] Direction Decision Module: This module synthesizes the gradient direction by measuring the rate of change of phase difference in orthogonal directions. This embodiment uses three orthogonal loop antennas to measure the rate of change of field phase in the X, Y, and Z directions respectively. Through vector synthesis, the spatial phase gradient direction can be directly calculated.

[0079] In this specific embodiment, 10 robots operate simultaneously, each performing 100 pickup tasks: average navigation time: 65 seconds / task; end-effector positioning accuracy: ±0.5mm; collision count: 0; real-time navigation communication usage: 0 kbps; hardware cost is approximately 1 / 5 of the traditional laser SLAM solution. Furthermore, for electromagnetically sensitive environments, the above radio frequency solution can be replaced with 40kHz ultrasound. The reference oscillation source is replaced with an ultrasonic transducer array, the phase-shifting beacon uses a DSP (Digital Signal Processor) for phase shifting, and the robot uses a piezoelectric ceramic receiver; the remaining principles remain the same.

[0080] In some embodiments, the method and / or system of this application can also be applied to semiconductor factories (wafer fabs / packaging and testing plants). Semiconductor factories are characterized by high cleanliness of cleanrooms, dense equipment, complex paths, extremely high requirements for the handling accuracy of materials (wafer pods, photomask pods), parallel scheduling of multiple machines, controllable electromagnetic environment, and prohibition of mechanical navigation facilities occupying space. The method and / or system of this application can be adapted to the flexible handling requirements of semiconductor factories that are unmarked, trackless, high-precision, and interference-resistant. For example, it can be used for the automated transfer of wafer pods, photomasks, reagent consumables, test samples, and carriers between various machines in the cleanroom within a semiconductor factory.

[0081] When applied in semiconductor factories, at least three frequency-locked, phase-locked reference oscillators can be installed in the ceiling and / or static pressure layer of the semiconductor cleanroom. These reference oscillators can employ radio frequency / microwave near-field coupling fields (low-frequency electromagnetic waves, no ionizing radiation, and no interference with the precision circuits of semiconductor equipment or photolithography exposure systems). The reference oscillators can be strictly phase-locked via wired synchronization cables, with the phase difference controlled to an extremely small angle, generating a uniform global coupling field covering the entire cleanroom work area, serving as a unified phase reference for all robots. The reference oscillators can be installed, for example, in the cleanroom ceiling, without occupying floor space and avoiding dust generation, thus meeting cleanroom requirements.

[0082] In some embodiments, each process machine port, wafer storage bin, temporary storage location, and loading / unloading port in a semiconductor plant can serve as a material demand point, with a small, sealed phase-shift beacon installed at each location. The beacon housing can be made of anti-static, corrosion-resistant cleanroom materials, suitable for cleanroom environments. Each beacon has a preset unique characteristic phase offset. After receiving the global coupled field, it re-radiates the local field with a fixed phase offset. Different machines correspond to different phase offsets, and robots can distinguish target workstations through phase differences, achieving workstation identification without QR codes or RFID tags.

[0083] In some embodiments, the handling robot may be, for example, a wafer handling AGV / AMR. The robot has built-in modules adapted to cleanrooms, and its orientation decision module can be equipped with an orthogonal loop antenna array to measure phase gradients and quickly point to the target machine (such as semiconductor equipment). The robot's minute displacement is suitable for the complex environment of cleanrooms with densely packed machines and narrow paths. The robot's environmental perception module can detect field distortions in the global coupling field caused by metal machines and wafer cells blocking the path, triggering obstacle avoidance to prevent collisions with precision semiconductor equipment. The robot's end effector precision positioning sensor can be equipped with cleanroom-grade laser ranging and vision sensors. When the phase difference is less than a threshold (close to the target machine), it can switch to precision positioning mode to achieve micron-level precise docking between the FOUP and the machine port.

[0084] In some embodiments, when a handling robot is performing handling operations in a semiconductor factory, the following workflow may be executed: Global field establishment: The reference oscillation source continuously emits a phase-locked global coupling field, covering the entire clean area; Target workstation coding: Each machine in the semiconductor plant outputs a unique phase offset field from its phase shift beacon to mark material demand points; Robot global navigation: The handling robot locks the global field phase, detects the phase difference of the target beacon through a phase comparator, and moves along the direction of the fastest decrease in phase difference to achieve large-scale unmarked autonomous navigation; Environmental obstacle avoidance: The environmental perception module detects coupling field distortion caused by machines, personnel, and obstacles, and adjusts the path in real time to ensure safety in the clean room; Precise docking at the end point: When the robot approaches the machine and the phase difference is less than the threshold, it switches to vision / laser precision positioning to complete precise docking and loading / unloading of wafer pods (FOUPs); Multi-robot collaborative scheduling: Different robots rely on a global phase reference to naturally distinguish their spatial positions, avoiding congestion and interference among multiple robots in the clean room.

[0085] Therefore, when the method and / or system of this application are applied to semiconductor factories, wafer contamination is avoided because there are no ground magnetic strips, QR code stickers, or dust-free positioning markers. The low-frequency controllable global coupling field does not interfere with lithography, inspection, or precision measurement equipment. When adjusting semiconductor equipment or reconfiguring production lines, only the beacon phase offset needs to be adjusted, without the need to re-lay navigation tracks. It also meets the micron-level docking requirements for wafer handling and supports multi-robot cluster scheduling, adapting to the 24-hour uninterrupted production needs of semiconductor factories.

[0086] Furthermore, it is understood that the foregoing embodiments are merely illustrative examples of the present invention. Provided that the technical features do not conflict, the structure is not contradictory, and the purpose of the invention is not violated, the technical solutions of the various embodiments can be arbitrarily combined and used.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A material handling system, characterized in that, include: A reference oscillation source is used to generate a global coupled field covering the work area; Multiple phase-shifting beacons are respectively arranged at each material demand point. Each phase-shifting beacon includes circuitry for receiving the global coupled field, performing phase-shifting processing based on a preset characteristic phase offset, and re-radiating. Multiple transport robots, each transport robot including: A lockable oscillator for synchronization with the global coupling field; A phase comparator, electrically connected to the lockable oscillator, is used to detect the real-time phase difference between its own oscillator and the received phase-shifting beacon radiation field; A direction decision module is electrically connected to the phase comparator, and the direction decision module is used to determine the spatial direction in which the phase difference decreases the fastest. A motion controller is electrically connected to the phase comparator and the direction decision module, respectively. The motion controller is used to drive the robot to move according to the phase difference and the direction determined by the direction decision module.

2. The material handling system according to claim 1, characterized in that, The direction decision module calculates the phase gradient by measuring the field phase change rate in different directions using multiple sets of orthogonal loop antennas, or learns the gradient direction online by controlling the robot to make small displacements and comparing the phase difference changes before and after the displacement.

3. The material handling system according to claim 1, characterized in that, The global coupling field is generated by radiation from at least three frequency-locked and phase-locked reference oscillators, which maintain a phase difference of less than a preset angle between each other through a wired synchronization cable or a wireless synchronization protocol.

4. The material handling system according to claim 1, characterized in that, The transport robot also includes an environmental perception module, which is electrically connected to the motion controller. The environmental perception module is used to detect changes in the surrounding environment and send an obstacle avoidance signal to the motion controller based on the changes in the physical characteristics of the global coupled field to trigger an obstacle avoidance response.

5. The material handling system according to claim 1, characterized in that, The handling robot also includes an end-effector precision positioning sensor, which is electrically connected to the phase comparator and the motion controller. The end-effector precision positioning sensor includes one or more of a vision sensor, a laser rangefinder, and a mechanical contact sensor. When the real-time phase difference is less than the preset threshold, the handling robot switches to end-effector precision positioning mode and is guided by the end-effector precision positioning sensor to complete the final alignment.

6. The material handling system according to claim 1, characterized in that, The lockable oscillator is a second-order phase-locked loop circuit. The handling robot also includes a receiving antenna and a low-noise amplifier. The robot receives a global coupled field signal through the receiving antenna. The low-noise amplifier is used to amplify the global coupled field signal. The amplified global coupled field signal serves as the reference input of the second-order phase-locked loop circuit.

7. The material handling system according to claim 6, characterized in that, The second-order phase-locked loop circuit includes a phase detector, a loop filter, and a voltage-controlled oscillator (VCO). The phase detector compares the phase difference between the reference signal and the feedback signal of the VCO to generate an error voltage. After passing through the loop filter, the frequency of the VCO is adjusted so that the output frequency of the VCO gradually approaches the reference frequency. When the frequency of the VCO is equal to the reference frequency and the phase difference is constant, the second-order phase-locked loop circuit enters a locked state.

8. The material handling system according to claim 7, characterized in that, The difference between the output frequency of the robot's internal oscillator and the global coupling field frequency is less than ±10ppm, which is determined to be frequency lock.

9. The material handling system according to claim 1, characterized in that, After the robot is powered on, it executes the following process: The receiving antenna scans the direction of the strongest signal, and the receiving gain is adjusted to make the signal amplitude appropriate. The received signal is used as a reference input, the initial frequency of the voltage-controlled oscillator is set to the nominal value, and a closed loop is formed. If the monitor locks the signal and fails to lock within a preset time, it will adjust the direction or gain of the receiving antenna and retry. If it still fails after multiple retries, it will output a fault alarm signal.

10. The material handling system according to claim 9, characterized in that, During operation, the phase comparator continuously monitors the phase difference between its own oscillator and the receiving field; if the phase difference changes abruptly by more than 30° and lasts for more than 1 second, it is determined that the lock has been lost, the robot stops moving, and the synchronization process is re-executed.

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