Design And Fuzzy Control Of Humanoid Elbow Driven By Penumatic Muscles

Pneumatic muscle(PM)joint is an important reference structure for developing the evolving together robot and establishing robot-human cooperation system by its merits such as light weight,perfect flexibility and bionic.However,the position control accuracy of PM joint is influenced by its defect such as nonlinearity and hysteresis.Two problems are investigated in this paper: one is the structure design of humanoid elbow joint driven by PM,and the other is the fuzzy control of it.Technical specifications are determined by reference to adult arm parameters.The kinematic model of elbow joint was est ablished and two elbow joint schemes are designed: cascade elbow joint and gear transmission elbow joint.Develop the two virtual prototypes after analyzing the feasibility of cascade mechanism and simulate and demonstrate the cascade scheme.Select the model of PMs based on the kinematic model of elbow joint.Obtain 3 sets of humanoid joints and established the control system of the second cascade humanoid joint.Simplify the three-element model of PM and get the relationship among PMs' force?PMs' length and PMs' coefficient of elasticity.Establish the PMs' model through experiment.What's more,the humanoid elbow joint model and elbow joint compliance model were established.Finally,step response test and PI curve tracking test were taken for cascade elbow joint.The current angle and compliance of elbow joint as input of the fuzzy controller,K with respect to upper and lower arm angle ratio and PI parameters as output,experiment is designed to establish fuzzy control rules of a cascade of elbow joint.Simulation for fuzzy PI control of cascade elbow joint based on MATLAB Fuzzy toolbox,is contrasted with conversation PI.Results show that the fuzzy PI control can enhance the accuracy of position tracking effectively.Fuzzy PI control experimental platform is established for experimental study on PI control and fuzzy PI control of the elbow joint respectively.Fuzzy PI control experiments are carried out in the two situation of certain and variable mass load respectively.Experiments show that the fuzzy PI control can effectively increase the swing amplitude of the elbow joint when the elbow carries the load.It can also improve the position tracking accuracy of elbow joint with load.