Research On Control Algorithms Of Bionic Humanoid Upper Arm Driven By Pneumatic Muscle Actuators

With the rapid and continuous development of science and technology,the application of robots is becoming more and more extensive.In particular,the development of service-oriented robots makes the anthropomorphism of the robot more important.Based on theoretical research of human shoulder anatomy,the bionic humanoid upper arm of a series-parallel structure is constructed by referring to the structural characteristics of the human upper arm.Pneumatic muscle actuator is a new type of pneumatic component,which has the characteristics similar to the biological muscles.By analyzing the characteristics of the pneumatic muscle,a single pneumatic muscle test platform is set up,and the mathematical model of the pneumatic muscle actuator is established through the test data.The trajectory tracking control is the research emphasis of mechanical manipulator.It is required that the joints have accurate track tracking performance so that the end trajectory can be moved according to the desired trajectory.First,the kinematics of the mechanism is analyzed from the configuration of series and parallel connection.Based on this,we use Lagrange equation to establish the dynamic model of scapula and glenohumeral parallel joint.In addition,due to the strong coupling characteristics of human upper arm mechanism,we use genetic algorithm(GA)to carry out smooth trajectory planning of joints under certain terminal position trajectory.Secondly,the fixed-point motion and trajectory tracking motion of scapula and glenohumeral joint were performed by PD controller and computed torque method respectively.According to the poor adaptability of the computed torque method of the internal loop fixed parameters,the fuzzy torque controller is designed based on the advantages of fuzzy control and computed torque control,which reduces the tracking error and improves the adaptability of the controller.In fact,considering the existence of interference and uncertainty,a sliding mode controller is proposed.From the simulation results,although some chattering is inevitable,the sliding mode controller has higher control accuracy and faster response speed.Finally,the hardware experimental system is established.In the actual control test of prototype,both of fuzzy torque control algorithm and sliding mode control algorithm obtain good control performance.