Research On Adaptive Impedance Control Of Parallel Legged Hexapod Walking Robot

With the development and progress of technology,robots are increasingly being used in various fields of modern society.As a research hotspot in the field of robotics,parallel legged walking robots have natural advantages in dealing with complex environments.In order to enhance the adaptability of parallel legged walking robots to the environment,this paper focuses on the research of compliant control related to parallel legged hexapod walking robots.Firstly,the structure of the parallel legged hexapod walking robot was designed and the 6-UPUR parallel mechanism of the robot leg was analyzed.The inverse kinematics position analysis of the robot was carried out,and a gait was designed.The robot and simulation environment were modeled using Simulink/Simscape software.Secondly,the principle of impedance control is introduced,and the position-based impedance control method is described in detail.The influence of changing the desired impedance parameters on the control performance is analyzed.Considering the structural characteristics of the parallel legged hexapod walking robot,a position-based impedance control system is constructed,and its effectiveness is verified through simulations.Thirdly,The shortcomings of the position-based impedance control algorithm in facing complex and unknown environments were analyzed,and two major factors affecting the control effect were obtained,namely the inability to obtain the change in actual environmental position relative to the expected environmental position in advance,and the inability to obtain the actual environmental stiffness in advance.In response to the problem of unknown environmental position,a posture controller was designed based on the structural characteristics of the parallel legged hexapod walking robot to reduce the influence of environmental position changes on the robot posture.To address the issue of unknown environmental stiffness,a variable stiffness-based adaptive impedance control algorithm was proposed based on the position-based impedance control.The effectiveness and adaptability of the compliant control system composed of the posture controller and adaptive impedance controller were verified through simulations under different environmental positions and stiffness.Finally,using the STM32 microprocessor as the core,multiple sensors were installed on the robot to construct the adaptive compliant system designed in this paper.Experiments were carried out with the robot facing different obstacles.The results show that the adaptive compliant control algorithm designed in this paper has compliance and adaptability when facing obstacles of different heights and stiffness.