CN-121989213-A - CPG distributed control system and method for snake-shaped robot

Abstract

The invention relates to the technical field related to control of snake-shaped robots, in particular to a CPG distributed control system and a CPG distributed control method of a snake-shaped robot, wherein the system comprises 11 CPG units corresponding to different modules, each CPG unit is an independent Hopf oscillator, a rhythm propagation chain is formed through hierarchical bus communication, and a multi-source sensing, main control coordination and execution driving module is matched. The method comprises the steps of initialization, environment sensing, rhythm generation and the like, can dynamically adjust parameters, adopts head leading and tail trailing phase synchronization and reinforcement learning to optimize feedback coefficients, and has a modularized redundancy design. The invention improves the response speed, fault tolerance and motion efficiency of the robot in a multi-medium environment, and is suitable for complex scene operation.

Inventors

• ZHANG YIXIN
• WANG SHAOPING
• ZHENG ZHENG
• WU TONG
• WANG GUANZHE
• ZHANG MENGKUN
• LIU CHENG
• LIU XINYU
• HAN YUTAO
• CHEN ZHIBIN
• JIA LE

Assignees

• 北京航空航天大学

Dates

Publication Date

20260508

Application Date

20260311

Claims (6)

1. 1. A CPG distributed control system of a snake-shaped robot is characterized by comprising a distributed CPG network, a multi-source sensing module, a main control coordination unit and an execution driving module; The distributed CPG network consists of 11 CPG units, which correspond to 1 head main control module, 6 rotational joint connection modules, 3 ducted fan modules and one tail driving module of the robot respectively, and each CPG unit is an independent Hopf nonlinear oscillator and can autonomously generate a periodic oscillation signal; the CPG units realize coupling communication through a hierarchical bus communication protocol, and the adjacent units dynamically adjust the signal transmission intensity through a weighting coefficient to form a rhythm propagation chain from head to tail; the multi-source sensing module comprises a force feedback sensor, and the binocular vision SLAM system comprises a dual-band infrared and visible light camera and an Inertial Measurement Unit (IMU) and is used for acquiring the motion state and environmental information of the robot; The main control coordination unit is integrated in the head main control module, adopts OpenRB-150Arduino main control boards and is used for initializing CPG network parameters, receiving multi-source sensing data and triggering global adjustment instructions; The execution driving module comprises steering engines and ducted fan driving units of all the modules, receives rhythm signals output by the CPG unit and drives joints or ducts to act.
2. 2. The CPG distributed control system of a snake-shaped robot of claim 1, wherein the output signal parameters of the Hopf nonlinear oscillator include amplitude, frequency and phase, which can be dynamically adjusted by the following formula: Amplitude adjustment: a=a 0 +k 1 ・F_feedback（A 0 is the initial amplitude, k 1 is the feedback coefficient, and f_feedback is the force feedback signal); frequency adjustment, f=f 0 +k 2 ・V_vision（f 0 is the initial frequency, k 2 is the visual coefficient, and v_vision is the environmental complexity parameter output by the visual system; The CPG network adopts a modularized redundant design, and when any 1-2 CPG units fail, adjacent units can take over the rhythm generation tasks thereof through coupling communication, so that the overall motion continuity is maintained.
3. 3. The CPG distributed control system of a snake-shaped robot according to claim 1, wherein the multi-source sensing module and the CPG unit form closed loop feedback, the force feedback sensor is used for collecting interaction force between joints and correcting phase difference of adjacent CPG units, the binocular vision SLAM system is used for generating an environment three-dimensional map based on ORB-SLAM algorithm and used for globally adjusting frequency base lines of the CPG network, and the IMU data is used for compensating oscillation signal drift of the CPG units in real time.
4. 4. A CPG distributed control method of a snake-shaped robot, as in any of the claims 1-3, characterized by comprising the following steps: Step 1, initializing, wherein a main control coordination unit sets initial oscillation parameters for each CPG unit, wherein the amplitude A 0 , the frequency f 0 and the phase difference phi 0 are set according to a preset motion mode, and the parameter values are distributed in a self-adaptive mode in land crawling, water swimming and air flying modes; Step 2, environmental perception, wherein a multisource perception module collects topographic features (land), water flow speed (in water) or air flow disturbance (air), and image data are processed through an OpenCV algorithm to generate an environmental complexity coefficient C; step 3, generating rhythms, namely independently generating oscillation signals by each CPG unit based on a Hopf equation, and synchronizing phases by adjacent units through coupling communication to form periodic fluctuation propagated along a snake body; Step 4, feedback adjustment, namely when the force feedback sensor detects that the joint stress exceeds a threshold value, increasing amplitude amplification of a corresponding CPG unit in real time is in direct proportion to the stress, and when the vision system identifies an obstacle, the master control coordination unit triggers the CPG network to reduce the frequency by 20% -50%, and simultaneously adjusts the phase difference between the head CPG unit and the tail CPG unit to realize steering; step 5, mode switching, namely when the robot moves across media, such as entering water from land, the main control unit sends a mode switching instruction, the CPG network automatically resets initial parameters, and rhythm propagation rules are reestablished; and 6, fault-tolerant control, namely if one CPG unit fails, detecting abnormality by an adjacent unit through bus communication, automatically adjusting the output of a coupling weight connecting tube rhythm signal, and maintaining local motion continuity.
5. 5. The method of claim 4, wherein in the step 3, the phase synchronization of the CPG units adopts a head-end leading mechanism and a tail-end following mechanism, the head CPG unit is used as a master oscillator, and then the phase phi n =φ 0 +n of the nth unit is equal to the delta phi, wherein delta phi is the basic phase difference of the adjacent units, the land mode delta phi = pi/5, the in-water mode delta phi = pi/8, and the flight mode delta phi = 0.
6. 6. The method of claim 4, wherein in step 4, a reinforcement learning mechanism is introduced to optimize a feedback adjustment coefficient, the movement distance and the energy consumption of the robot motion efficiency per unit time are taken as a reward function, and the CPG parameter adjustment strategy is adapted to different environments by continuously and iteratively updating the k 1 force feedback coefficient and the k 2 visual coefficient.

Description

CPG distributed control system and method for snake-shaped robot Technical Field The invention relates to the technical field related to control of snake-shaped robots, in particular to a CPG distributed control system and a CPG distributed control method of a snake-shaped robot. Background In the field of snake-shaped robot control, a traditional centralized control architecture has obvious short plates, and the traditional centralized control architecture relies on a single central controller to process all signals and issue instructions, so that signal congestion is very easy to occur when the number of joints of the robot is large, and response delay is greatly increased, for example, in a scene of needing to quickly avoid obstacles, the centralized control often misses the optimal avoidance time due to a large number of processing links, and the real-time requirement in actual operation is seriously different. The existing CPG control technology has certain application in the field of bionic robots, but aiming at the defect of insufficient adaptability of the snake-shaped robots, the CPG network structure adopted by part of technologies is fixed, the number of units cannot be flexibly adjusted according to the actual module configuration of the robots, the CPG control technology is difficult to match with the snake-shaped robots with 11 corresponding modules, in addition, the communication mode among CPG units is simple, mostly the signal transmission with fixed strength, and the dynamic adjustment through the weighting coefficient cannot be realized as described in the claims, so that the coordination of each joint of the robots is poor when the robots move in a complex mode. In terms of parameter adjustment, an output parameter adjustment mechanism of the CPG oscillator in the prior art is stiff, and effective coupling with multi-source information such as force feedback, visual sense and the like is lacking, so that adaptability is greatly reduced when a robot moves in different terrains or mediums, meanwhile, feedback closed loops of a multi-source sensing module and a CPG unit are not fully constructed, and the force feedback, visual SLAM and IMU data are all battle, so that an organic whole cannot be formed, and control accuracy is affected. In addition, the fault tolerance of the existing system is weak, and when an individual control unit fails, the overall motion disturbance is easily caused. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a distributed control system and method for a snake-shaped robot CPG, which solve the problems of slow response, poor adaptability and weak fault tolerance of the traditional control mode, and easy overall motion disorder when an individual control unit fails. In order to achieve the above purpose, the invention provides a CPG distributed control system of a snake-shaped robot, which comprises: the system is designed by adopting a distributed CPG network, a multi-source sensing module, a main control coordination unit and an execution driving module to cooperatively work, wherein the distributed CPG network consists of 11 CPG units, accurately corresponds to different functional modules of a robot and comprises 1 head main control module, 6 rotary joint connecting modules, 3 ducted fan modules and 1 tail driving module. Each CPG unit is an independent Hopf nonlinear oscillator and has the capability of autonomously generating a periodic oscillation signal. CPG units are communicated and coupled by means of hierarchical bus communication protocol, and signal transmission intensity is flexibly adjusted between adjacent units through dynamically adjustable weighting coefficients, so that an ordered rhythm propagation chain from head to tail is constructed, the units can keep relatively independent operation, high-efficiency coordination can be realized, and the coordination of the overall motion of the robot is ensured. The multi-source sensing module is formed by integrating a force feedback sensor, a binocular vision SLAM system, a dual-band infrared and visible camera and an inertial measurement unit IMU, wherein the force feedback sensor monitors the interaction force between joints in real time and provides a key basis for parameter adjustment of a CPG unit, the binocular vision SLAM system generates a high-precision environment three-dimensional map by utilizing an advanced ORB-SLAM algorithm, the frequency baseline of the CPG network is adjusted globally by aid of assistance, and the IMU is used for compensating drift possibly occurring in oscillation signals of the CPG unit in real time and ensuring accurate sensing of a robot on the state and surrounding environment in all directions. The main control coordination unit is integrated in the head main control module, and is a OpenRB-150 main control board, and the core functions of the main control coordination unit comprise initializing CPG network parameters, endo