Research On Muscular-Elastic Actuation Theory And Compliant Motion Of Robot

The compliant motion of robot is one of important research goals in the field of robot science and intelligent control,as well as a key technology in advanced manufacturing system.It requires the robot not only to achieve accurate positioning and stable motion,but also to make real-time adjustments to respond to changes in external conditions.Rely on position control and torque control,however,it does not consider the effect of the external environment on the influence of the robot motion,relevant feedback is not timely collected and effective treated,which is not able meet the requirements of robot's adaptive motion in a complex environment.However,the existing robot actuation mode and motion form also have shortcomings such as insufficient flexibility,excessive rigidity and low energy efficiency,which cannot effectively generate the desired compliant motion.Therefore,more advanced actuation theory and intelligent control strategy are needed to realize the compliant motion of the robot.Related studies show that after long time of evolution in nature,the human body has formed a comprehensive set of advanced sports organization system,which contains the musculoskeletal system can ensure implementation in the process of motion based on the rapid response of conditioned reflex action and the rhythm of lasting stability behavior,and in advanced under the control of the nervous system.It can also make appropriate active adjustment according to the information feedback of environmental conditions,and has the very good exercise spontaneity and controllable capabilities.Therefore,the compliant motion of robot can be realized by simulating the joint actuation form and the motion posture characteristics of the human body.This paper firstly introduces the series elastic actuator(SEA),combined with Hill-type muscle model in human body to explore an elastic actuate approach of mimicking muscletendon's mechanical structure and motion characteristics,to design and develop a controllable bionic robot study platform with muscular-elastic characteristics,including single actuated joint,2-DOF robot arm and multiple DOFs biped robot in simulation and physical environment,to apply such as the software of MSC/Adams,Matlab and OpenSim to establish the relevant kinematics and dynamics simulation model,and rationality and practicability are verified.In fact,the muscular-elastic actuator is mainly the improvement of the classical SEA actuation model.According to the dynamic analysis and joint configuration structure of robot,a novel feed-forward compensation control method based on virtual spring stiffness is proposed to meet the requirements of joint motion's compliance.In addition,a fuzzy PID control method is proposed and relevant simulation driving experiments are carried out in the research of mimicking humanoid compliant walking gaits by combining the theory of muscular-elastic actuation theory and human musculoskeletal motion architecture.Since musculoskeletal motion system is a complex nonlinear system,the muscular-elastic actuation also has nonlinear characteristics,and the control strategy has a great influence on the robot's compliant motion.Based on the analysis of the motion forms and biomechanics of actual human joints and the characteristics of elastic actuation mechanism,the nonlinear differential dynamic equation is established to linearize the non-linear system.For the single-muscle actuation model and antagonistic muscle actuation model,the model predictive control method and backstepping control method are proposed respectively.Toward compliant motion of robot,the feasibility of the muscular-elastic actuation of the joints,the basic theory of non-linear elastic actuation,the realization of the elastic joint self-tuning behavior and motion of compliant control problems are discussed and studied in this paper,which provides new ideas and methods for the development and scientific research for the application of bionic actuation in robot field.