Multi-mobile platform cooperative control method and system

Abstract

The invention relates to the technical field of automatic control and robots, and particularly provides a multi-mobile-platform cooperative control method and system, and the method comprises the following steps: receiving instruction frames synchronously broadcasted by a central control terminal through each mobile platform, and calculating a clock offset with the central control terminal; based on the clock skew, correcting the timestamp of each mobile platform in combination with the dynamic compensation of the output frequency of the constant-temperature crystal oscillator on the clock skew; each mobile platform verifies the instruction frame based on the received instruction frame, and generates a confirmation frame after the verification is passed; and after the central control terminal collects the confirmation frames of all the mobile platforms, synchronously outputting a control instruction signal to the corresponding execution module through each mobile platform at the execution moment. According to the multi-mobile-platform cooperative control method and system provided by the invention, the synchronism, reliability and execution precision stability of multi-mobile-platform cooperative operation can be improved.

Description

TECHNICAL FIELD

[0001] The application relates to the field of automation control and robot technology, in particular to a multi-mobile platform cooperative control method and system. BACKGROUND

[0002] With the development of automation technology, multi-mobile platform cooperative work systems are increasingly widely used in logistics, warehousing, large equipment installation and other scenarios, in which mobile platforms such as AGV (Automated Guided Vehicle) trolleys, handling robots and the like are used. The core challenge of such cooperative work systems is how to ensure that all platforms can achieve accurate synchronization of actions under unreliable wireless communication environment and ensure reliable transmission of instructions.

[0003] The multi-mobile platform cooperative work system in the related art adopts a master-slave type instruction issuing mode, that is, a master controller sends control instructions to each slave device in turn. This mode has the following inherent defects:

[0004] (1) Poor synchronization: due to the inherent delay and jitter of the wireless network, there is a difference in the time when different slave devices receive instructions, resulting in different starting times of actions.

[0005] (2) Low reliability: the instruction issuing relies on a single communication path and is easily affected by interference or packet loss.

[0006] (3) Unstable execution precision: there is a lack of local compensation mechanism for the execution differences of each mobile platform and external disturbances, making it difficult to achieve high-precision cooperation in complex industrial environments.

[0007] In view of the problems of poor synchronization, low reliability and unstable execution precision of the multi-mobile platform cooperative work system in the related art, no effective solution has been proposed so far. SUMMARY

[0008] The multi-mobile platform cooperative control method and system provided by the embodiments of the application at least solve the problems of poor synchronization, low reliability and unstable execution precision of the multi-mobile platform cooperative work system in the related art.

[0009] To achieve the above-mentioned purpose, the application provides the following technical solutions:

[0010] In one aspect, the application provides a multi-mobile platform cooperative control method, comprising the following steps: receiving, by each mobile platform, an instruction frame synchronously broadcast by a central control terminal, and calculating a clock deviation from the central control terminal; wherein the timestamp of the instruction frame comprises a generation time of the instruction frame, a broadcast time and an execution time of all mobile platforms; based on the clock deviation, combining dynamic compensation of the clock deviation by a constant temperature crystal oscillator output frequency, correcting the timestamp of each mobile platform; based on the received instruction frame, each mobile platform checks the instruction frame, and generates a confirmation frame after passing the check; after the central control terminal collects the confirmation frames of all mobile platforms, each mobile platform synchronously outputs a control instruction signal to a corresponding execution module at the execution time; wherein the control instruction signal is a target motion speed extracted by each mobile platform based on the instruction frame, and is calculated after optimizing proportional-integral-derivative coefficients based on local collected actual speed and state estimation data.

[0011] Preferably, receiving, by each mobile platform, an instruction frame synchronously broadcast by a central control terminal, and calculating a clock deviation from the central control terminal, comprises the following steps: broadcasting the instruction frame by the central control terminal to each mobile platform synchronously; wherein the instruction frame is generated by the central control terminal based on an input execution task; receiving the instruction frame by each mobile platform, and obtaining a time difference between each mobile platform and the central control terminal based on a difference between a local time of receiving the instruction frame and the broadcast time; obtaining a communication delay estimation value of each mobile platform based on two independent timestamp interactions between the central control terminal and each mobile platform; wherein the communication delay estimation value is a difference between bidirectional delay estimation values between the central control terminal and the mobile platform; inputting the communication delay estimation value and the time difference into a time offset estimation model, and outputting a corresponding clock deviation of each mobile platform by the time offset estimation model; wherein the time offset estimation model is constructed according to a relationship that the clock deviation is equal to a difference between the time difference and the communication delay estimation value.

[0012] Preferably, the expression of the time offset estimation model is: ; wherein, represents a time deviation of the i th mobile platform from the central control terminal; represents a local time of the i th mobile platform receiving the instruction frame; represents a broadcast time of the central control terminal; represents a delay estimation value transmitted by the i th mobile platform to the central control terminal; represents a delay estimation value transmitted by the central control terminal to the i th mobile platform.

[0013] Preferably, based on the clock bias, the dynamic compensation of the clock bias in combination with the output frequency of the oven-controlled crystal oscillator, the time stamp of each mobile platform is corrected, including the following steps: based on the clock bias, the drift rate of the clock bias over time is calculated by linear fitting; based on the temperature deviation of the oven-controlled crystal oscillator of each mobile platform, in combination with the output frequency and the frequency-temperature coefficient of the oven-controlled crystal oscillator, the first correction amount of the output frequency associated with temperature is calculated; based on the drift rate, in combination with the local clock frequency of each mobile platform, the second correction amount of the output frequency associated with the drift rate is calculated; based on the first correction amount and the second correction amount, the output frequency is dynamically corrected to obtain the corrected crystal oscillator output frequency; based on the corrected crystal oscillator output frequency, in combination with the difference between the broadcast time and the local time, the time stamp of each mobile platform is corrected.

[0014] Preferably, based on the received instruction frame, each mobile platform verifies the instruction frame and generates an acknowledgement frame after verification, including the following steps: after receiving the instruction frame, each mobile platform reassembles the data fragments in the instruction frame to recover the lost data fragments in the instruction frame; wherein the instruction frame includes N original data fragments and K redundant check fragments; N and K are both natural numbers; when the recovery rate of the data fragments reaches a set threshold, the cyclic redundancy check value is calculated by each mobile platform based on the recovered fragments; when the cyclic redundancy check value is consistent with the central check value calculated by the central control terminal, each mobile platform performs freshness check based on the sequence number of the received data fragments; when the freshness check of the sequence number is qualified, the corresponding mobile platform generates an acknowledgement frame.

[0015] Preferably, before each mobile platform synchronously outputs a control instruction signal to the corresponding execution module at the execution time, the method further includes the following steps: the central control terminal collects the acknowledgement frames of each mobile platform, when the central control terminal collects the acknowledgement frame of the target mobile platform and the verification is successful, the criterion of the corresponding mobile platform is recorded as "1", otherwise as "0"; based on the criterion of each mobile platform, a consistency index is calculated; wherein the consistency index is calculated according to the ratio of the sum of all criteria to 1; when the consistency index is less than 1, the central control terminal sends a suspension frame to all mobile platforms, so that all mobile platforms enter a safe standby state; when the consistency index is equal to 1, all mobile platforms enter a standby execution state.

[0016] Preferably, before each of the mobile platforms synchronously outputs the control instruction signal to the corresponding execution module at the execution moment, the method further comprises the following steps: based on the instruction frame, extracting a target motion speed of each of the mobile platforms; based on the target motion speed and a local motion speed of each of the mobile platforms, calculating a speed error of each of the mobile platforms; based on the speed error and state estimation data of each of the mobile platforms, dynamically adjusting a proportional-integral-derivative coefficient under the condition of satisfying a constraint function; wherein the constraint function comprises an error convergence constraint function and a stability constraint function; the state estimation data comprises a position and an attitude angle; based on the proportional-integral-derivative coefficient, calculating the control instruction signal; wherein the control instruction signal comprises a target voltage and / or a target current of the motor.

[0017] Preferably, the constraint function has an expression as follows: ; ; wherein, represents the speed error at the t moment; represents a precision threshold value; is a mathematical logic symbol, representing "any one"; represents a local moment of each of the mobile platforms; represents a broadcast moment of the central control terminal; represents a first-order derivative of a Lyapunov function with respect to time; represents a first-order derivative of the speed error with respect to time; represents a proportional coefficient of the PID controller at the t moment; represents an integral coefficient of the PID controller at the t moment.

[0018] Preferably, the target voltage has a calculation formula as follows: ; ; ; ; wherein, represents the target voltage at the t moment; is an integral temporary variable, representing any one of the moments between the 0 moment and the t moment; represents a differential variable of the PID controller at the t moment; represents a proportional coefficient initial value; represents a proportional adjustment coefficient; represents an integral coefficient initial value; represents an integral adjustment coefficient; represents a differential coefficient initial value; represents a differential adjustment coefficient; represents a second-order derivative of the speed error with respect to time.

[0019] Another aspect of the present application provides a multi-mobile platform cooperative control system, comprising: a central control terminal, a plurality of mobile platforms and an execution module; each of the mobile platforms comprises: a wireless communication module, configured to receive an instruction frame synchronously transmitted by the central control terminal; wherein a timestamp of the instruction frame comprises: a generation time of the instruction frame, a broadcast time and an execution time of all the mobile platforms; a clock synchronization module, connected with the wireless communication module, configured to calculate a clock deviation of the mobile platform from the central control terminal based on the instruction frame, and combine a dynamic compensation of the clock deviation with an output frequency of a constant temperature crystal oscillator to correct the timestamp of the mobile platform; a control module, connected with the wireless communication module and the clock synchronization module, configured to control each of the mobile platforms to synchronously output a control instruction signal to the corresponding execution module at the execution time after the central control terminal collects an acknowledgement frame of all the mobile platforms; wherein the acknowledgement frame is generated by each of the mobile platforms after receiving the instruction frame when the instruction frame passes the verification; and the control instruction signal is calculated by each of the mobile platforms based on a target motion speed in the instruction frame, combining actual speed and state estimation data collected locally to optimize proportional-integral-derivative (PID) coefficients.

[0020] The above technical solution of the present application has the following beneficial effects compared with the prior art:

[0021] The multi-mobile platform cooperative control method and system provided by the embodiments of the present application first broadcast an instruction frame to each mobile platform synchronously through a central control terminal, and each mobile platform dynamically compensates the clock deviation based on the received instruction frame, combines the constant temperature crystal oscillator output frequency to correct the timestamp, thereby ensuring the clock synchronization of each mobile platform, reducing the difference in instruction receiving time caused by clock difference, and ensuring the synchronization of action start. Moreover, the plurality of mobile platforms synchronously output control instructions at the same execution time, avoiding the problem of different device action start synchronization caused by wireless network delay and jitter. Secondly, each mobile platform verifies the received instruction frame and generates an acknowledgement frame after the verification passes, and the central control terminal needs to collect the acknowledgement frames of all the mobile platforms before allowing each mobile platform to synchronously output a control instruction signal at the execution time, which can ensure the correct reception and processing of the instruction and reduce the reliability problem caused by instruction error or loss. Finally, by optimizing the proportional-integral-derivative (PID) coefficients, each mobile platform can adjust the control instruction according to its actual situation, compensating for the execution difference of each mobile platform and the influence of external disturbance, thereby improving the stability of the execution precision and solving the problems of poor synchronization, low reliability and unstable execution precision of the mobile platform cooperative work system in the related art. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required by the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other embodiments can also be obtained from these drawings without creative labor.

[0023] Figure 1 is a flowchart of a multi-mobile platform cooperative control method of an embodiment of the present application.

[0024] Figure 2 is a flowchart of key steps of a multi-mobile platform cooperative control method of an embodiment of the present application.

[0025] Figure 3 is a structural block diagram of a multi-mobile platform cooperative control system of an embodiment of the present application.

[0026] Figure 4 is a structural diagram of an electronic device of the present application. DETAILED DESCRIPTION

[0027] The embodiments of the present application will be described in detail with reference to the drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms, and should not be interpreted as being limited to the embodiments set forth herein, but rather, these embodiments are provided to more thoroughly and completely understand the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes, and are not intended to limit the scope of protection of the present application.

[0028] In order to improve the synchronization, reliability and execution precision stability of multi-mobile platform cooperative operation, an embodiment of the present application provides a multi-mobile platform cooperative control method and system.

[0029] As shown in Figure 1 , wherein the multi-mobile platform cooperative control method provided by an embodiment of the present application comprises the following steps S1 to S4.

[0030] Step S1, receiving an instruction frame broadcasted synchronously by a central control terminal through each mobile platform, and calculating the clock deviation from the central control terminal; wherein the time stamp of the instruction frame comprises the generation time of the instruction frame, the broadcast time and the execution time of all mobile platforms.

[0031] Step S2, based on the clock deviation, combining the dynamic compensation of the constant temperature crystal oscillator output frequency to the clock deviation, and correcting the time stamp of each mobile platform.

[0032] Step S3, each mobile platform checks the instruction frame based on the received instruction frame, and generates a confirmation frame after the check is passed.

[0033] Step S4, when the central control terminal collects the confirmation frames of all mobile platforms, it synchronously outputs control instruction signals to the corresponding execution modules at the execution time through each mobile platform; wherein the control instruction signal is the target motion speed extracted by each mobile platform based on the instruction frame, combined with the actual speed and state estimation data collected locally, and calculated after the proportional-integral-derivative coefficient is optimized.

[0034] Specifically, the mobile platform in step S1 is a device or system with autonomous mobile capability, executable specific task and communication capability with the central control terminal, used for receiving instructions and executing specific carrying tasks.

[0035] The mobile platform can include: ground mobile platform (such as autonomous navigation robot, unmanned delivery vehicle, AGV car), air mobile platform (multi-rotor unmanned aerial vehicle, fixed-wing unmanned aerial vehicle), water mobile platform (unmanned ship, water robot) and underwater mobile platform (underwater robot, submersible) and the like.

[0036] These mobile platforms are usually equipped with sensors, communication modules, driving modules and control modules, etc., so that they can perceive the environment, receive instructions and realize autonomous movement.

[0037] The central control terminal is used for human-computer interaction, task planning, generation and broadcast of collaborative control instructions. It is internally provided with a main processor, a memory, a wireless communication module and a high-precision clock master station.

[0038] The central control terminal can include: special control server (such as industrial computer, server deployed in ground base station or control center), portable control terminal (such as professional tablet computer, customized control box), industrial control host (such as programmable logic controller PLC or industrial computer embedded in automation system) and vehicle / carried control center (such as integrated control system installed on command vehicle, mother ship and other carriers) and the like.

[0039] The instruction frame is generated by the central control terminal according to the input execution task, and is a standardized data unit for transmitting control information between the central control terminal and each mobile platform.

[0040] The structure of the instruction frame of the embodiment of the application preferably comprises: frame header, instruction ID (identifier), time stamp, control instruction, target platform list, sequence number, CRC (Cyclic Redundancy Check, cyclic redundancy check) check code and / or frame tail.

[0041] The frame header is generally 2 bytes and fixedly indicates 0xAA55.

[0042] The instruction ID is generally 4 bytes, is a unique identification serial number of a task, and is for example a digital representation of CMD-20250925-001. The ID is a key for subsequent confirmation and suspension mechanisms.

[0043] The timestamp is generally 8 bytes, includes a generation time, a broadcast time and an execution time of all mobile platforms of the instruction frame, is in a Unix time format, and has an accuracy of microseconds.

[0044] The target platform list is generally variable length bytes and includes platform IDs, such as [200a, 200b, 200c], that need to execute the instruction, is used for specifying an action object of the instruction, and ensures that the instruction is sent only to target mobile platforms. 200a, 200b and 200c are three mobile platforms.

[0045] The serial number is for example a monotonically increasing counter, is used for preventing repeated execution or expired execution of the instruction, and ensures timeliness and uniqueness of the instruction.

[0046] The CRC check code is generally 2 bytes, performs cyclic redundancy check (for example, a CRC-16-CCITT algorithm) on the entire data frame (except the frame header and the check code itself), and is used for checking whether the instruction frame is tampered with or damaged in a transmission process and guaranteeing data integrity.

[0047] The frame tail is generally 2 bytes, a fixed identifier 0x55AA, is used for identifying an end of the instruction frame, and is used in cooperation with the frame header to complete boundary identification of the instruction frame.

[0048] The above fields and lengths are at least one implementation manner, and can be adjusted according to a bandwidth and a safety policy.

[0049] The instruction frame structure of the embodiment of the application provides a reliable data transmission basis for the entire cooperative control system by containing fields such as a timestamp, a unique instruction ID, a target platform list and a check code, and a core function thereof is to ensure that an instruction is received and identified by a correct platform in a correct time and in a complete and correct manner, thereby laying a key data basis for realizing subsequent accurate synchronous execution.

[0050] The central control terminal sends a built cooperative control instruction frame in a broadcast or multicast form through a wireless communication module thereof. Meanwhile, the terminal starts a “confirmation timer” for the instruction ID, for example, the timer is set to 200 milliseconds and can be self-adapted according to network conditions.

[0051] Clock bias refers to the fixed time difference between the local clock of each mobile platform and the reference clock of the central control terminal. The clock bias can be estimated by one-way broadcast delay or measured based on round-trip propagation time.

[0052] The constant temperature crystal oscillator in step S2 is a high-precision frequency generator. The constant temperature crystal oscillator has a quartz crystal resonator inside and generates a stable frequency oscillation signal through electricity. The oscillation signal is the "heartbeat" of the digital clock, and each cycle is counted once to time.

[0053] Each mobile platform is equipped with a constant temperature crystal oscillator, and the time flow rate of the corresponding mobile platform can be determined through the constant temperature crystal oscillator.

[0054] In step S2 of the embodiment of the present application, the frequency of the local crystal oscillator is determined to be fast or slow by analyzing the trend of the clock bias, and a correction voltage is applied to the voltage control pin of the constant temperature crystal oscillator to fine-tune the output frequency, thereby correcting the "fast or slow" of the clock from the root cause, dynamically compensating the clock bias, aligning the clocks of all mobile platforms in "time", and keeping the clocks of all mobile platforms consistent with the master clock in "flow rate" for a long time, thereby achieving high-precision synchronization.

[0055] In step S3, each mobile platform checks the instruction frame after receiving the instruction frame to determine whether the frame data is valid, complete and reliable. Common checking methods include cyclic redundancy check, protocol compliance check and sequence number verification.

[0056] If there is a bit error or a fragment loss in the data frame during transmission, the receiving end first uses forward error correction (FEC) or a sliding window retransmission mechanism to repair and recover the complete data. If a mesh network is used, the arrival rate can also be improved by using a multi-path redundancy method.

[0057] The confirmation frame is generated by the mobile platform after the current instruction frame is checked to be correct. The content of the confirmation frame usually includes the local identifier, the sequence number of the confirmed instruction, the local state information (such as "ready", "busy" or sensor reading), and / or the self-check code.

[0058] The embodiment of the present application checks the instruction frame by each mobile platform and generates a confirmation frame, thereby providing each mobile platform with the guarantee of instruction correctness and local readiness. It ensures that the mobile platform will not execute incorrect instructions, and actively announces to the collaborative work system that the instruction has been correctly received and is ready, and provides a judgment basis and collaboration basis for the central control terminal to issue instructions, so that the central control terminal can issue synchronization execution instructions after collecting the confirmations of all platforms.

[0059] Further, in step S4, the central control terminal collects the confirmation frames of all mobile platforms, and issues a synchronous execution instruction, so that each mobile platform outputs the control instruction signal at the execution time, locks each mobile platform to a common and preset "execution time", and ensures that the control instruction signals of all platforms can be output with high precision in time and space, eliminates the action disorder caused by individual response delay and clock difference, and is the key to realizing close cooperative action (such as maintaining formation and cooperative operation).

[0060] Proportional-integral-derivative coefficient, corresponding to the three core parameters of a PID (Proportional-Integral-Derivative) controller.

[0061] In step S4 of the embodiment of the present application, the proportional-integral-derivative coefficient is optimized based on the target motion speed extracted from the instruction frame and the actual speed and state estimation data collected locally, for example: when the target speed is high and the actual speed is far from the target speed, the P coefficient can be temporarily reduced to avoid violent oscillation; when the system detects that there is an external load (uphill) that causes a steady-state error, the I coefficient can be intelligently enhanced; when the actual speed quickly approaches the target, the D coefficient can be enhanced to "step on the brake" to prevent overshoot, thereby improving the response speed and accuracy of each mobile platform, enhancing the robustness of the system, and ensuring the cooperation between each mobile platform.

[0062] The execution module is a hardware unit on the mobile platform that finally converts the control instruction into physical action, and can include: a motor driver / controller, a servo, a hydraulic / pneumatic control valve, and / or a switching value output device.

[0063] The control instruction signal is the final command sent by the mobile platform to the execution module after the central control terminal plans and calculates it, and it is the "nerve signal" of the control chain.

[0064] The control instruction signal can include: target speed, target torque, target current, target voltage, target position / angle, and / or target PWM (Pulse Width Modulation) duty cycle of the driving motor, etc.

[0065] The control instruction signal is generated by the PID controller through a core calculation process. This process is based on the comprehensive evaluation of the current, history and trend of the error, multiplies the "current error" by the proportional coefficient, adds the "historical cumulative error" multiplied by the integral coefficient, and adds the "error change speed" multiplied by the derivative coefficient. Finally, the sum of the three calculation results is the final control instruction signal. This mechanism can realize fast response, accurate tracking and stable control at the same time.

[0066] This invention provides a multi-mobile platform collaborative control method. First, a central control terminal synchronously broadcasts command frames to each mobile platform. Each mobile platform, based on the received command frames, dynamically compensates for clock deviations by incorporating the output frequency of a temperature-controlled crystal oscillator, correcting timestamps and ensuring clock synchronization across all platforms. This reduces differences in command reception time caused by clock discrepancies and guarantees synchronous action initiation. Furthermore, multiple mobile platforms synchronously output control commands at the same execution time, avoiding asynchronous action initiation issues caused by wireless network latency and jitter.

[0067] Secondly, each mobile platform verifies the received command frames and generates an acknowledgment frame after the verification is successful. The central control terminal needs to collect the acknowledgment frames from all mobile platforms before allowing each mobile platform to synchronously output control command signals at the execution time. This ensures the correct reception and processing of commands and reduces reliability issues caused by command errors or loss.

[0068] Finally, by optimizing the proportional-integral-derivative (PID) coefficients, each mobile platform can adjust its control commands according to its own actual situation, compensating for the differences in execution between mobile platforms and the impact of external disturbances, thereby improving the stability of execution accuracy. This can solve the problems of poor synchronization, low reliability and unstable execution accuracy in mobile platform collaborative operation systems in related technologies.

[0069] Furthermore, step S1 in the embodiments of the present invention preferably includes steps S11 to S14.

[0070] Step S11: Broadcast instruction frames synchronously to each mobile platform through the central control terminal; wherein, the instruction frames are generated by the central control terminal based on the input execution task.

[0071] Step S12: Receive instruction frames through each mobile platform, and obtain the time difference between each mobile platform and the central control terminal based on the difference between the local time of the received instruction frame and the broadcast time.

[0072] Step S13: Based on two independent timestamp interactions between the central control terminal and each mobile platform, the estimated communication delay for each mobile platform is obtained; wherein, the estimated communication delay is the difference between the estimated bidirectional delay between the central control terminal and the mobile platform.

[0073] Step S14: Input the estimated communication delay and time difference into the time offset estimation model, and output the clock offset corresponding to each mobile platform through the time offset estimation model; wherein, the time offset estimation model is constructed based on the relationship that the clock offset is equal to the difference between the time difference and the estimated communication delay.

[0074] Specifically, in step S11, the central control terminal executes a task such as: "Move 2m forward in a straight line at 0.5m / s in 10 seconds." Based on this task, the central control terminal generates a corresponding instruction frame.

[0075] In step S12, the time difference is the difference between the local time when each mobile platform receives the instruction frame and the broadcast time.

[0076] In step S13, the two independent timestamp exchange processes can be the clock synchronization process in the IEEE 1588PTP protocol, including:

[0077] The first interaction (downlink: central control terminal → mobile platform): When the central control terminal is preparing to send a command frame, it records a precise transmission timestamp T1. Upon receiving the command frame, the mobile platform records a reception timestamp T2 based on its local clock.

[0078] The second interaction (uplink: mobile platform → central control terminal): After processing the instruction frame, the mobile platform immediately generates an acknowledgment frame and records a transmission timestamp T3 when sending the acknowledgment frame. The central control terminal records a reception timestamp T4 the instant it receives the acknowledgment frame.

[0079] Through multiple timestamp interactions, the system continuously records the send and receive timestamps. Based on these timestamp sequences, the system employs a statistical estimation algorithm to separate and estimate the downlink communication delay from the observed data, thereby obtaining the estimated values ​​for the downlink communication delay from the central control terminal to the mobile platform, and the uplink communication delay from the mobile platform to the central control terminal.

[0080] The estimated communication latency for each mobile platform is the difference between the estimated uplink communication latency and the estimated downlink communication latency.

[0081] In step S14, the time offset estimation model is constructed based on the relationship that clock offset equals the difference between time difference and estimated communication delay.

[0082] Therefore, after calculating the time difference and the estimated communication delay, the clock deviation of each mobile platform can be obtained by subtracting the estimated communication delay from the time difference.

[0083] Furthermore, the preferred expression for the time offset estimation model is as follows: (1).

[0084] (1).

[0085] in, This represents the time deviation between the i-th mobile platform and the central control terminal; This represents the local time at which the i-th mobile platform receives the instruction frame; Indicates the broadcast time from the central control terminal; This represents the estimated delay for the i-th mobile platform to transmit data to the central control terminal. This represents the estimated delay for transmission from the central control terminal to the i-th mobile platform.

[0086] The time offset estimation model provided by the present invention effectively separates the two variables "clock offset" and "communication path delay" that are mixed together in a simple measurement by introducing an estimate of network delay asymmetry, thereby filtering out measurement noise caused by network delay and outputting a purer and more accurate clock offset value.

[0087] Through steps S11 to S14 above, the embodiments of the present invention can accurately estimate the network communication delay asymmetry between the central control terminal and each mobile platform, and use this estimated value to correct the initial time difference, ultimately achieving high-precision measurement of the clock deviation of each mobile platform, laying a key foundation for subsequent absolute time synchronization.

[0088] Furthermore, step S2 in the embodiments of the present invention preferably includes steps S21 to S25.

[0089] Step S21: Based on the clock skew, calculate the drift rate of the clock skew over time through linear fitting.

[0090] Step S22: Based on the temperature deviation of the thermostatic crystal oscillators of each mobile platform, and combined with the output frequency and frequency temperature coefficient of the thermostatic crystal oscillators, calculate the first correction amount of the temperature-related output frequency.

[0091] Step S23: Based on the drift rate and combined with the local clock frequency of each mobile platform, calculate the second correction amount of the output frequency associated with the drift rate.

[0092] Step S24: Dynamically correct the output frequency based on the first correction amount and the second correction amount to obtain the corrected crystal oscillator output frequency.

[0093] Step S25: Based on the corrected crystal oscillator output frequency and the difference between the broadcast time and the local time, correct the timestamp of each mobile platform.

[0094] Specifically, in step S21, linear fitting involves treating the clock deviation as a linear function of time and fitting it using the least squares method, resulting in the following linear model: ,in, This represents the time deviation between the i-th mobile platform and the central control terminal at time t. Indicates the drift rate. This represents the fitting intercept (initial deviation correction term).

[0095] The drift rate calculated in step S21 is the core parameter for subsequent crystal oscillator frequency adjustment.

[0096] In step S22, the formula for calculating the first correction amount is: ,in, This indicates the first correction amount. The frequency temperature coefficient, in ppm / ℃, represents the deviation rate of the crystal oscillator frequency per 1℃ change. This indicates the crystal oscillator's operating temperature, in °C. The sampling frequency and clock drift rate sampling period are kept consistent (e.g., 100ms). This indicates the nominal operating temperature of the crystal oscillator; This indicates the nominal output frequency of the crystal oscillator.

[0097] In step S23, the formula for calculating the second correction amount is: ;in, Indicates the second deviation; This indicates the local clock frequency.

[0098] In step S24, the total frequency correction is obtained by summing the first and second correction values: ;in, This indicates the total frequency correction amount.

[0099] Based on the total frequency correction, the total frequency correction can be applied to the nominal output frequency through additive or multiplicative correction. or local clock frequency The corrected crystal oscillator output frequency can then be obtained. .

[0100] In step S25, the corrected local clock is: = ;in, This indicates the corrected local clock. This indicates the local clock before the correction. This indicates the time of the central control terminal during the last synchronization. N represents the local counter value at the time of the last synchronization; N represents the current local counter value.

[0101] Steps S21 to S25 of this invention employ a temperature-controlled crystal oscillator and a software drift compensation algorithm. First, the inherent aging drift rate of the clock is identified through a linear model. Then, the instantaneous frequency deviation caused by temperature and drift rate is calculated. The total correction amount, synthesized from these two main error sources, is used to feedforward adjust the crystal oscillator output, fundamentally calibrating the frequency reference. Finally, this high-precision frequency source is used to drive the local clock, minimizing its accumulated error. The entire process ensures that the output local time can maintain stable synchronization with the master clock at the microsecond level or even higher precision over a long period, effectively overcoming the aging and temperature drift problems of the crystal oscillator.

[0102] The multi-layer timestamp synchronization architecture provided in steps S1 and S2 of this invention embeds multi-layer timestamp fields, including "generation time," "broadcast time," and "execution time," into the control command frame. After receiving the command, the mobile platform performs secondary calibration based on the local time offset ∆t and the master clock error model to form the "logical execution time." This multi-layer timestamp structure can actively eliminate the superposition errors of broadcast delay and clock drift.

[0103] Unlike existing simple trigger-based timestamps, this invention achieves microsecond-level trigger synchronization through a clock skew estimation model and a dynamic time correction table. Even under network latency of 50ms and jitter of ±10ms, the trigger deviation is still less than 20 microseconds.

[0104] Furthermore, to ensure reliable transmission of collaborative control commands in a wireless communication environment, this invention designs a Collaborative Task Reliable Transmission Protocol (CT-RTP) based on traditional FEC and ACK mechanisms. This protocol inserts a lightweight consistency judgment and error correction layer between the data link layer and the task management layer to implement command redundancy verification, data recovery, and multi-node consistency verification. In the embodiments of this invention, step S3 preferably includes steps S31 to S34.

[0105] Step S31: After receiving the instruction frame, each mobile platform reassembles the data fragments in the instruction frame to recover the lost data fragments in the instruction frame; wherein, the instruction frame includes N original data fragments and K redundancy check fragments; N and K are both natural numbers.

[0106] Step S32: When the data fragment recovery rate reaches the set threshold, the cyclic redundancy check value is calculated based on the recovered fragments by each mobile platform.

[0107] Step S33: When the cyclic redundancy check value is consistent with the central check value calculated by the central control terminal, each mobile platform performs freshness check based on the sequence number of the received data fragment.

[0108] Step S34: When the freshness verification of the serial number is qualified, a confirmation frame is generated through the corresponding mobile platform.

[0109] Specifically, in step S31, the present invention preferably employs the CT-RTP protocol and the Reed-Solomon(N,K) encoding scheme to split the instruction frame into N fixed-length data fragments (Packet_i), and performs forward error correction coding (FEC) on each fragment to generate K redundant parity fragments. The resulting dataset includes the original data fragments and the redundant fragments (N+K) to improve packet loss resistance; for example, N=12, K=4.

[0110] The encoded dataset is broadcast simultaneously across multiple communication paths via a mesh network, such as the primary path (P1) and a backup path (P2). Each mobile platform can receive complete or partial data from either path.

[0111] After receiving the instruction frame, each mobile platform uses an FEC algorithm (such as Reed-Solomon or LDPC code) to recover the lost fragments.

[0112] In step S32, the recovery rate is obtained based on the ratio of the total number of recovered data fragments to the total number of original data fragments.

[0113] When the recovery rate is greater than or equal to a set threshold (e.g., 90%), proceed to the next verification step; otherwise, request a retransmission. After successfully recovering the command frame, each platform calculates the CRC checksum based on the CRC checksum extracted from the command frame and the command ID.

[0114] Furthermore, in step S33, after the CRC check passes, the freshness of the sequence number is calculated based on the sequence number extracted from the instruction frame, and the freshness is checked.

[0115] In step S34, if the serial number freshness verification fails, the instruction frame is discarded. If the verification passes, the mobile platform's control module, such as the local controller 203, can parse the instruction ID and target platform list from the instruction frame. If the mobile platform's own ID is in the list, an acknowledgment frame (ACK) is immediately constructed, which contains at least its own platform ID and the acknowledged instruction ID. This ACK frame is then sent to the central control terminal 100 via the wireless module.

[0116] Furthermore, the preferred structure of the ACK frame is: ACK = {Platform ID, Instruction ID, Verification Result, Execution Timestamp}.

[0117] Steps S31 to S34 in the embodiments of this invention constitute a communication error correction mechanism process, implemented through a custom Cooperative Task Reliable Transmission Protocol (CT-RTP). Specifically, it includes five stages: data fragmentation redundancy, FEC error correction, multi-path redundancy, ACK aggregation determination, and abort rollback. It can achieve a recovery rate >99% with a packet loss rate of 20%. The ACK aggregation timeout is adaptively adjusted from 200 to 1000 ms, supporting multi-path parallel broadcast and retransmission mechanisms.

[0118] Compared to existing TCP retransmission or UDP broadcast, the CT-RTP protocol of this invention introduces a "consistency judgment layer" between the link layer and the task layer. This layer not only corrects data errors but also determines whether each node is in the same task state, thereby ensuring both communication reliability and task execution consistency. This method effectively distinguishes and solves the three problems of "synchronous triggering," "precise execution," and "reliable transmission," and employs different technical means to ensure each, thus achieving high-precision and high-reliability collaborative control at the system level.

[0119] Furthermore, in this embodiment of the invention, the method preferably includes steps S041 to S044 before step S4.

[0120] Step S041: Collect confirmation frames from each mobile platform through the central control terminal. When the central control terminal collects the confirmation frame of the target mobile platform and verifies it successfully, record the corresponding mobile platform's criterion as "1", otherwise record it as "0".

[0121] Step S042: Calculate the consistency index based on the criteria of each mobile platform; wherein the consistency index is calculated based on the ratio of the sum of all criteria to 1.

[0122] Step S043: When the consistency index is less than 1, the central control terminal sends an abort frame to all mobile platforms, causing all mobile platforms to enter a safe standby state.

[0123] Step S044: When the consistency index equals 1, all mobile platforms enter the pending execution state.

[0124] In step S41, the central control terminal first constructs a consistency criterion vector based on the instruction frame, such as: V = [ACK_1, ACK_2, …, ACK_n].

[0125] Secondly, when the central control terminal collects an acknowledgment frame from the target mobile platform, and it matches the consistency criterion vector, the verification result is "successful," thus determining that the task consistency is achieved. If some nodes' ACKs time out or the verification fails, the abort process is triggered.

[0126] For M target platforms, their ACK frame states constitute a consistency vector: .in, The criterion for the i-th mobile platform is... .

[0127] In step S042, the formula for calculating the consistency index is: .

[0128] in, Indicators of consistency, if =1 indicates that task consistency is achieved; if If the value is less than 1, the termination mechanism will be triggered.

[0129] Furthermore, when the consistency judgment is not valid, i.e. When the value is less than 1, the central control terminal immediately broadcasts an abort frame to all mobile platforms: STOP={instruction ID, abort flag, reason code}.

[0130] The abort mechanism must put all platforms into a safe standby state within T_safe≤50ms and record the abort reason code to prevent the risk of task residue.

[0131] Upon receiving an abort frame, the platform removes the task from the execution queue. If some platforms have already entered the execution preparation state, they immediately switch to safe standby mode to prevent the risk of "partial execution".

[0132] The embodiments of the present invention provide steps S041 to S044, which introduce an "instruction consistency judgment layer" on the basis of the traditional FEC and ACK mechanism. This layer is used to determine whether the acknowledgment frames of each node are synchronized to the same instruction ID and execution timestamp. This can ensure task consistency and system security even in wireless network environments with packet loss rates as high as 20%.

[0133] Furthermore, during the "acknowledgment timer" operation, the central control terminal continuously listens for and collects ACK frames from various mobile platforms.

[0134] Successful scenario: Within the 200-millisecond acknowledgment timeout, the central control terminal 100 successfully received valid ACKs from all platforms (200a, 200b, 200c) in the target platform list. At this point, the terminal determines that the collaborative task has been successfully deployed, marks the task status as "pending execution," and waits for the execution timestamp to arrive.

[0135] Failure Scenario: If ACKs from all target platforms are not received by the 200ms acknowledgment deadline (e.g., only ACKs from 200a and 200b are received, but not from 200c), the terminal determines that the task deployment has failed. To prevent security incidents, the terminal immediately generates and broadcasts an abort instruction frame (carrying the original instruction ID and an abort flag). This frame contains the same instruction ID as before and an "abort" flag.

[0136] Execution of the abort command: When a platform that has stored pending tasks (such as 200a and 200b) receives the abort command, it will search for and delete the corresponding task in its pending task queue according to the command ID, thereby canceling the original action and ensuring that no partial nodes are executed erroneously.

[0137] Furthermore, in this embodiment of the invention, the method preferably includes steps S045 to S048 before step S4.

[0138] In step S045, the target motion speed of each mobile platform is extracted based on the instruction frame.

[0139] Step S046: Calculate the speed error of each mobile platform based on the target motion speed and the local motion speed of each mobile platform.

[0140] Step S047: Based on the velocity error and the state estimation data of each mobile platform, dynamically adjust the proportional-integral-derivative coefficients under the condition of satisfying the constraint functions; wherein, the constraint functions include: error convergence constraint function and stability constraint function; the state estimation data include: position and attitude angle.

[0141] Step S048: Calculate the control command signal based on the proportional-integral-derivative coefficients; wherein the control command signal includes: the target voltage and / or target current of the motor.

[0142] Specifically, the instruction frame preferably includes the target motion speed of each mobile platform, and the target motion speed can be parsed from the data field of the instruction frame in step S045.

[0143] Furthermore, the local motion speed and state estimation data of each mobile platform can be obtained through multiple sensors. For example, the rotational speed and displacement of each mobile platform can be collected through a motor encoder, and the position and attitude angle of each mobile platform can be collected through an IMU (Inertial Measurement Unit).

[0144] Taking the mobile platform 200a as an example, its local controller instructs the motor to start rotating at a speed corresponding to 0.5 m / s. During the movement, the controller continuously reads real-time data from the motor encoder from the sensor module at a frequency of milliseconds to calculate the actual speed and displacement of the platform.

[0145] The speed error of each mobile platform is obtained by subtracting the target speed from the local speed of each mobile platform.

[0146] Step S047 preferably involves using a PID controller with a distributed closed-loop compensation method, embedding an adaptive gain adjustment module based on the cumulative rate of execution error, and dynamically adjusting the proportional-integral-derivative coefficients based on the speed error and the state estimation data of each mobile platform, while satisfying the constraint function.

[0147] Furthermore, the controller can correct the control model based on changes in ground friction or load fluctuations using a state estimator (based on the fusion of IMU and encoder). This preserves the stability of the PID algorithm while also providing self-learning characteristics, enabling adaptive compensation for individual platform differences.

[0148] The adjustment formula for the proportional-integral-derivative coefficients is as follows:

[0149] .

[0150] .

[0151] .

[0152] in, This represents the proportional gain of the PID controller at time t; This represents the integral coefficient of the PID controller at time t; This represents the differential variable of the PID controller at time t; This represents the initial value of the proportional coefficient; This represents the proportional adjustment coefficient; This represents the velocity error at time t; This represents the first derivative of the velocity error with respect to time. Indicates the initial value of the integral coefficient; This represents the integral adjustment coefficient; Indicates the initial value of the differential coefficient; Represents the differential adjustment coefficient; This represents the second derivative of the velocity error with respect to time.

[0153] The local controller internally runs an adaptive PID control algorithm. This algorithm compares the real-time measured speed with the command-set 0.5 m / s to obtain the error e(t). Based on this error, the PID controller adjusts the duty cycle or current of the PWM signal output to the motor driver in real time to dynamically correct the speed, ensuring that the platform's actual motion trajectory closely matches the command, regardless of changes in ground friction or load fluctuations.

[0154] The embodiments of this invention are based on the initial values ​​of each coefficient of the PID controller. Based on the absolute values ​​of the first derivative of the speed error (|ė(t)|, the absolute value of the speed error (|e(t)|), and the absolute value of the second derivative of the speed error (|ë(t)|), the proportional coefficient is dynamically corrected using the proportional control coefficient α, the integral control coefficient β, and the derivative control coefficient γ. Integral coefficient and differential coefficients This allows the PID controller to flexibly adjust the control force based on the magnitude, rate of change, and acceleration of the real-time error, thereby responding more quickly to error changes, effectively eliminating static errors, reducing system overshoot and oscillations, and improving overall control accuracy and stability. This control law maintains stable system response under varying ground friction and load conditions, significantly improving execution accuracy.

[0155] Furthermore, the expression for the constraint function is:

[0156] (2).

[0157] (3).

[0158] in, This represents the velocity error at time t; Indicates the precision threshold; It is a mathematical logic symbol representing "any one"; Indicates the local time for each mobile platform; Indicates the broadcast time from the central control terminal; This represents the first derivative of the Lyapunov function with respect to time; This represents the first derivative of the velocity error with respect to time. This represents the proportional gain of the PID controller at time t; This represents the integral coefficient of the PID controller at time t.

[0159] Wherein, formula (2) is the stability constraint function, and formula (3) is the error convergence constraint function, preferably a Lyapunov function. This invention, by adding the above constraint functions, can ensure the stability and error convergence of the motor control: Formula (2) limits... The absolute value of the velocity error at any time after time step 1 does not exceed the accuracy threshold. This directly ensures that the steady-state control accuracy of the system meets the requirements; Formula (3) requires the derivative of the Lyapunov function V̇(t) to be always less than 0, which theoretically ensures that the speed error e(t) will continue to decrease and eventually converge to the allowable range, while avoiding unstable problems such as oscillation and divergence in the system. The combination of the two provides a double guarantee of accuracy and stability for PID control.

[0160] Furthermore, the formula for calculating the target voltage is:

[0161] ;

[0162] in, This represents the target voltage at time t; Let be a temporary variable for integration, representing any time between time 0 and time t.

[0163] The embodiments of this invention are based on dynamically adjusted proportions. ,integral ,differential The coefficients, respectively, are used for the current speed error e(t) and the error integral term. Error differential term By performing weighted summation, the target voltage u(t) at time t is obtained. The motor can be controlled accurately, stably, and quickly by combining the proportional term to quickly respond to the current error, the integral term to eliminate the static error, and the derivative term to suppress the error change in advance.

[0164] When the sensor data shows that the platform's displacement has reached the set target value, the local controller stops driving the motor, marking the completion of this task.

[0165] like Figure 2 , 3 As shown in the embodiment of the present invention, a multi-mobile platform collaborative control method, in its specific implementation, first performs system initialization and time synchronization: after all mobile platforms are powered on, a network connection is established with the central control terminal through the wireless communication module. Subsequently, the high-precision clock synchronization module of each platform automatically synchronizes its time with the clock master station of the central control terminal to establish a unified system time reference. After time synchronization, the system calculates the time offset ∆t of each node relative to the master controller and records it in the global synchronization table for dynamic correction of the execution timestamp during subsequent execution.

[0166] Secondly, collaborative task instruction generation: The operator sets the collaborative task (e.g., "move 2m in a straight line at 0.5 m / s in 10 seconds"). The terminal generates a structured unified control instruction frame.

[0167] Then, the command broadcast and closed-loop confirmation occur: the central control terminal sends out the constructed collaborative control command frame via its wireless communication module in the form of broadcast or multicast. Simultaneously, the terminal internally starts an "acknowledgment timer" for this command ID, for example, set to 200 milliseconds, which can adapt to network conditions.

[0168] After each mobile platform's wireless communication module receives the instruction frame, the local controller performs the following operations:

[0169] 1. Communication Error Correction: If a data frame has bit errors or fragment loss during transmission, the receiving end first uses forward error correction (FEC) or sliding window retransmission mechanisms to repair it and restore the complete data. If a mesh network is used, the arrival rate can also be improved through multipath redundancy.

[0170] 2. Verification: After error correction, extract the CRC checksum and sequence number, and perform the same CRC calculation on the received data. Verify the CRC against the sequence number's freshness; discard the data if they fail.

[0171] 3. ACK Confirmation: If the verification passes, the local controller parses the command ID and the target platform list. If its own ID is in the list, it immediately constructs an acknowledgment frame (ACK), which contains at least its own platform ID and the confirmed command ID. This ACK frame is then sent to the central control terminal via the wireless module.

[0172] 4. Store pending tasks: The local controller stores the instruction frame (especially the execution timestamp and control instructions) into a queue of pending tasks and sets an internal timer to prepare to trigger the task when the specified timestamp arrives. If the task is not collected, the deployment is deemed to have failed, the task is aborted, and the security arbitration and abort mechanism is initiated.

[0173] Finally, after the verification is passed, control command signals are synchronously output through each mobile platform, and distributed local closed-loop control is performed.

[0174] This invention provides a multi-mobile platform collaborative control method that integrates time synchronization accuracy, execution error compensation, and communication reliability within a unified control framework, with the parameters of these three components being interconnected and dynamically adaptively adjusted. This differs from existing technologies where each mechanism operates independently and is unaware of the others. Time synchronization accuracy, execution error compensation, and communication reliability work together through an adaptive algorithm. Specifically, time synchronization ensures synchronized platform execution through a Precise Time Protocol (PTP), execution error compensation dynamically adjusts control parameters through closed-loop control, and communication reliability guarantees instruction consistency and effective transmission through CRC and ACK mechanisms.

[0175] This invention proposes a collaborative control method and system that combines a unified multi-layer timestamp synchronization mechanism, distributed local closed-loop compensation, and communication error correction + acknowledgment / abortion mechanism. The control terminal embeds an absolute execution timestamp in the unified control command frame, and the platform synchronously triggers the task at a future absolute time, fundamentally separating network latency jitter from the triggering stage. The platform continuously corrects execution errors using closed-loop control; the link side ensures task consistency through a CT-RTP-based multi-path fault tolerance mechanism and ACK aggregation judgment, broadcasting abort commands when necessary to avoid "partial node execution." These three elements are coupled together to achieve high-precision, high-reliability collaborative control.

[0176] This invention provides a multi-mobile platform collaborative control system, applied to the multi-mobile platform collaborative control method provided in the above embodiments. The system includes: a central control terminal, multiple mobile platforms, and an execution module; each mobile platform includes: a wireless communication module, a clock synchronization module, and a control module.

[0177] The wireless communication module is used to receive instruction frames synchronously sent by the central control terminal; wherein the timestamp of the instruction frame includes: the generation time of the instruction frame, the broadcast time, and the execution time of all mobile platforms.

[0178] The clock synchronization module, connected to the wireless communication module, is used to calculate the clock deviation between the mobile platform and the central control terminal based on the instruction frame, and to correct the timestamp of the mobile platform by combining the dynamic compensation of the clock deviation with the output frequency of the thermostatic crystal oscillator.

[0179] The control module, connected to the wireless communication module and the clock synchronization module, is used to control each mobile platform to synchronously output control command signals to the corresponding execution module at the execution time after the central control terminal collects confirmation frames from all mobile platforms. The confirmation frame is generated by the mobile platform after receiving the command frame and when the command frame verification is successful. The control command signal is calculated by each mobile platform based on the target motion speed in the command frame, combined with the locally collected actual speed and state estimation data, and after optimizing the proportional-integral-derivative coefficients.

[0180] Furthermore, the wireless communication module adopts a Wi-Fi or ZigBee module that supports Mesh self-organizing networks.

[0181] The clock synchronization module, acting as a clock slave, receives the clock signal from the master station and maintains strict synchronization with the clock of the central control terminal 100 using Precision Time Protocol (PTP) or Network Time Protocol (NTP), with synchronization accuracy reaching the microsecond level.

[0182] The control module is preferably a local controller, typically a high-performance microcontroller (MCU) or embedded processor. It serves as the brain of the platform, responsible for parsing instructions, executing control algorithms, and managing sensors and drivers. The control algorithm is preferably implemented on the STM32 platform.

[0183] The execution module includes a DC or AC servo motor and its driver, which directly controls the movement of the wheels.

[0184] The present invention provides a multi-mobile platform collaborative control system, which firstly broadcasts instruction frames to each mobile platform synchronously through a central control terminal, and each mobile platform receives the instruction frames through a wireless communication module.

[0185] Next, the clock synchronization module dynamically compensates for clock deviations based on the received command frames and the output frequency of the constant temperature crystal oscillator. This corrects the timestamps, thereby ensuring clock synchronization across all mobile platforms, reducing differences in command reception time caused by clock differences, and guaranteeing the synchronization of action initiation.

[0186] Finally, the control module controls each mobile platform to verify the received command frames and generates an acknowledgment frame after the verification is successful. The central control terminal needs to collect the acknowledgment frames from all mobile platforms before allowing each mobile platform to synchronously output control command signals at the execution time. This ensures the correct reception and processing of commands and reduces reliability issues caused by command errors or loss.

[0187] Furthermore, by controlling multiple mobile platforms to synchronously output control commands at the same execution moment through the control module, the problem of asynchronous startup of different devices due to wireless network latency and jitter is avoided. The control module also optimizes the proportional-integral-derivative (PID) coefficients, enabling each mobile platform to adjust its control commands according to its own actual situation. This compensates for the differences in execution between mobile platforms and the impact of external disturbances, thereby improving the stability of execution accuracy and solving the problems of poor synchronization, low reliability, and unstable execution accuracy in mobile platform collaborative operation systems in related technologies.

[0188] Therefore, the multi-mobile platform collaborative control method and system provided by the present invention can achieve the following technical effects:

[0189] 1. High synchronization accuracy: The synchronization mechanism based on absolute timestamps eliminates the triggering error caused by network jitter in principle, achieving microsecond-level synchronization.

[0190] 2. High communication reliability: Through the communication error correction mechanism, the impact of packet loss and interference on task execution is effectively reduced, ensuring that instructions can be accurately received by various platforms.

[0191] 3. Strong system robustness: The distributed control architecture reduces the absolute dependence on the central controller and communication network, and the communication failure of a single node does not affect the collaborative operation of other nodes.

[0192] 4. Excellent adaptability: The local closed-loop controller of each platform can automatically adapt to its own state changes and external disturbances, ensuring the control accuracy and stability of the overall system.

[0193] This invention integrates time synchronization, closed-loop control, and communication error correction under a unified time reference to form a timing consistency guarantee framework. This framework can simultaneously solve the multi-source collaborative error problem caused by network latency, execution errors, and unreliable communication, representing a systematic improvement over existing independent control schemes.

[0194] Embodiments of the present invention also provide a non-transitory machine-readable medium storing a computer program, wherein the computer program, when executed by a computer's processor, is used to cause the computer to perform a method according to an embodiment of the present invention.

[0195] Embodiments of the present invention also provide a computer program product, including a computer program, wherein the computer program, when executed by a computer's processor, is used to cause the computer to perform the method of an embodiment of the present invention.

[0196] An embodiment of the present invention also provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor. The memory stores a computer program executable by the at least one processor, which, when executed by the at least one processor, causes the electronic device to perform the method of the embodiment of the present invention.

[0197] refer to Figure 4 This is a structural block diagram of an electronic device for a server or client, representing an embodiment of the present invention, and is an example of a hardware device that can be applied to various aspects of the present invention. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present invention described and / or claimed herein.

[0198] like Figure 4As shown, the electronic device includes a computing unit 801, which can perform various appropriate actions and processes based on a computer program stored in a read-only memory (ROM) 802 or a computer program loaded from a storage unit 808 into a random access memory (RAM) 803. The RAM 803 may also store various programs and data required for the operation of the electronic device. The computing unit 801, ROM 802, and RAM 803 are interconnected via a bus 804. An input / output (I / O) interface 805 is also connected to the bus 804.

[0199] Multiple components in the electronic device are connected to I / O interface 805, including: input unit 806, output unit 807, storage unit 808, and communication unit 809. Input unit 806 can be any type of device capable of inputting information into the electronic device. Input unit 806 can receive input digital or character information and generate key signal inputs related to user settings and / or function control of the electronic device. Output unit 807 can be any type of device capable of presenting information and may include, but is not limited to, a display, speaker, video / audio output terminal, vibrator, and / or printer. Storage unit 808 may include, but is not limited to, disks and optical discs. Communication unit 809 allows the electronic device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks, and may include, but is not limited to, modems, network cards, infrared communication devices, and / or wireless communication transceivers, such as Bluetooth devices, WiFi devices, WiMax devices, cellular communication devices, and / or the like.

[0200] The computing unit 801 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 801 include, but are not limited to, CPUs, graphics processing units (GPUs), various special-purpose artificial intelligence (AI) computing units, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. The computing unit 801 performs the various methods and processes described above. For example, in some embodiments, the method embodiments of the present invention can be implemented as computer programs tangibly contained in a machine-readable medium, such as storage unit 808. In some embodiments, part or all of the computer program can be loaded and / or installed on an electronic device via ROM 802 and / or communication unit 809. In some embodiments, the computing unit 801 can be configured to perform the methods described above by any other suitable means (e.g., by means of firmware).

[0201] Computer programs for implementing the methods of embodiments of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0202] In the context of embodiments of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable signal medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, or infrared systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0203] It should be noted that the term "comprising" and its variations used in the embodiments of this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "a plurality" mentioned in the embodiments of this invention are illustrative and not restrictive, and those skilled in the art should understand that unless explicitly indicated otherwise in the context, they should be understood as "one or more".

[0204] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in the embodiments of this invention are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0205] The steps described in the method embodiments provided by the present invention can be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of protection of the present invention is not limited in this respect.

[0206] The term "embodiment" in this specification refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily imply the same embodiment, nor does it imply independence or alternativeity from other embodiments. The various embodiments in this specification are described in a related manner, with reference to each other for similar or identical parts. In particular, for apparatus, device, and system embodiments, since they are substantially similar to method embodiments, the description is relatively simple, and relevant details are referred to in the description of the method embodiments.

[0207] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A multi-mobile platform collaborative control method, characterized in that, Includes the following steps: Each mobile platform receives instruction frames synchronously broadcast by the central control terminal and calculates the clock deviation with the central control terminal; wherein, the timestamp of the instruction frame includes: the generation time of the instruction frame, the broadcast time, and the execution time of all mobile platforms; Based on the clock deviation, and combined with the dynamic compensation of the clock deviation by the output frequency of the isothermal crystal oscillator, the timestamps of each of the mobile platforms are corrected. Each of the mobile platforms verifies the received instruction frame and generates an confirmation frame after the verification is successful. After the central control terminal collects confirmation frames from all the mobile platforms, each mobile platform synchronously outputs control command signals to the corresponding execution module at the execution time. The control command signals are calculated by each mobile platform based on the target motion speed extracted from the command frame, combined with the locally collected actual speed and state estimation data, and after optimizing the proportional-integral-derivative coefficients.

2. The multi-mobile platform collaborative control method according to claim 1, characterized in that, Receiving instruction frames synchronously broadcast by the central control terminal through each of the mobile platforms, and calculating the clock deviation with the central control terminal, includes the following steps: The central control terminal synchronously broadcasts the instruction frame to each of the mobile platforms; wherein the instruction frame is generated by the central control terminal based on the input execution task; The instruction frames are received by each of the mobile platforms, and the time difference between each mobile platform and the central control terminal is obtained based on the difference between the local time of receiving the instruction frames and the broadcast time. Based on two independent timestamp interactions between the central control terminal and each of the mobile platforms, the estimated communication latency of each mobile platform is obtained; wherein, the estimated communication latency is the difference between the estimated bidirectional latency between the central control terminal and the mobile platform. The estimated communication delay and the time difference are input into the time offset estimation model, and the clock offset corresponding to each mobile platform is output through the time offset estimation model; wherein, the time offset estimation model is constructed based on the relationship that the clock offset is equal to the difference between the time difference and the estimated communication delay.

3. The multi-mobile platform cooperative control method according to claim 2, characterized in that, The expression for the time offset estimation model is: ； in, This represents the time deviation between the i-th mobile platform and the central control terminal; This represents the local time at which the i-th mobile platform receives the instruction frame; Indicates the broadcast time from the central control terminal; This represents the estimated delay for the i-th mobile platform to transmit data to the central control terminal. This represents the estimated delay for transmission from the central control terminal to the i-th mobile platform.

4. The multi-mobile platform collaborative control method according to claim 1, characterized in that, Based on the clock deviation, and combined with dynamic compensation of the clock deviation by the output frequency of the isothermal crystal oscillator, the timestamps of each of the mobile platforms are corrected, including the following steps: Based on the clock deviation, the drift rate of the clock deviation over time is calculated by linear fitting; Based on the temperature deviation of the thermostatic crystal oscillators of each of the mobile platforms, and in combination with the output frequency and frequency temperature coefficient of the thermostatic crystal oscillators, a first correction amount of the temperature-related output frequency is calculated. Based on the drift rate, and in conjunction with the local clock frequency of each of the mobile platforms, a second correction amount for the output frequency associated with the drift rate is calculated; The output frequency is dynamically corrected based on the first correction amount and the second correction amount to obtain the corrected crystal oscillator output frequency. Based on the corrected crystal oscillator output frequency and the difference between the broadcast time and the local time, the timestamps of each mobile platform are corrected.

5. The multi-mobile platform cooperative control method according to claim 1, characterized in that, Each of the mobile platforms verifies the received instruction frame and generates an confirmation frame upon successful verification, including the following steps: After receiving the instruction frame, each of the mobile platforms reassembles the data fragments in the instruction frame to recover the lost data fragments in the instruction frame; wherein, the instruction frame includes N original data fragments and K redundancy check fragments; N and K are both natural numbers; When the recovery rate of the data fragments reaches a set threshold, the cyclic redundancy check value is calculated by each mobile platform based on the recovered fragments. When the cyclic redundancy check value is consistent with the central check value calculated by the central control terminal, each mobile platform performs a freshness check based on the sequence number of the received data fragment. When the freshness verification of the serial number is successful, a confirmation frame is generated through the corresponding mobile platform.

6. The multi-mobile platform cooperative control method according to claim 5, characterized in that, Before each of the mobile platforms synchronously outputs control command signals to the corresponding execution module at the execution time, the method further includes the following steps: The central control terminal collects the confirmation frames of each mobile platform. When the central control terminal collects the confirmation frame of the target mobile platform and verifies it successfully, the corresponding mobile platform's criterion is recorded as "1", otherwise it is recorded as "0". A consistency index is calculated based on the criteria of each of the mobile platforms; wherein the consistency index is calculated as the ratio of the sum of all the criteria to 1. When the consistency index is less than 1, the central control terminal sends an abort frame to all mobile platforms, causing all mobile platforms to enter a safe standby state. When the consistency index equals 1, all mobile platforms enter the pending execution state.

7. The multi-mobile platform cooperative control method according to claim 1, characterized in that, Before each of the mobile platforms synchronously outputs control command signals to the corresponding execution module at the execution time, the method further includes the following steps: Based on the instruction frame, the target motion speed of each of the mobile platforms is extracted; Based on the target motion speed and the local motion speed of each mobile platform, calculate the speed error of each mobile platform; Based on the speed error and the state estimation data of each of the mobile platforms, the proportional-integral-derivative coefficients are dynamically adjusted under the condition of satisfying the constraint functions; wherein, the constraint functions include: error convergence constraint function and stability constraint function; the state estimation data includes: position and attitude angle; Based on the proportional-integral-derivative coefficients, the control command signal is calculated; wherein, the control command signal includes: the target voltage and / or target current of the motor.

8. The multi-mobile platform cooperative control method according to claim 7, characterized in that, The expression for the constraint function is: ； ； in, This represents the velocity error at time t; Indicates the precision threshold; It is a mathematical logic symbol representing "any one"; Indicates the local time for each mobile platform; Indicates the broadcast time from the central control terminal; This represents the first derivative of the Lyapunov function with respect to time; This represents the first derivative of the velocity error with respect to time. This represents the proportional gain of the PID controller at time t; This represents the integral coefficient of the PID controller at time t.

9. The multi-mobile platform cooperative control method according to claim 8, characterized in that, The formula for calculating the target voltage is: ； ； ； ； in, This represents the target voltage at time t; Let be a temporary variable for integration, representing any time between time 0 and time t; This represents the differential variable of the PID controller at time t; This represents the initial value of the proportional coefficient; This represents the proportional adjustment coefficient; Indicates the initial value of the integral coefficient; This represents the integral adjustment coefficient; Indicates the initial value of the differential coefficient; Represents the differential adjustment coefficient; This represents the second derivative of the velocity error with respect to time.

10. A multi-mobile platform collaborative control system, characterized in that, include: Central control terminal, multiple mobile platforms, and execution modules; Each of the mobile platforms includes: The wireless communication module is used to receive instruction frames synchronously sent by the central control terminal; wherein the timestamp of the instruction frame includes: the generation time of the instruction frame, the broadcast time, and the execution time of all mobile platforms; A clock synchronization module, connected to the wireless communication module, is used to calculate the clock deviation between the mobile platform and the central control terminal based on the instruction frame, and to correct the timestamp of the mobile platform by combining the dynamic compensation of the clock deviation with the output frequency of the isothermal crystal oscillator. The control module, connected to the wireless communication module and the clock synchronization module, is used to control each mobile platform to synchronously output control command signals to the corresponding execution module at the execution time after the central control terminal collects confirmation frames from all the mobile platforms; wherein, the confirmation frame is generated by the mobile platform after receiving the command frame and when the command frame verification is successful; the control command signal is calculated by each mobile platform based on the target motion speed in the command frame, combined with locally collected actual speed and state estimation data, and after optimizing the proportional-integral-derivative coefficients.

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