Research And Design On Variable Stiffness Compliant Actuator Based On Antagonism

The industrial robots have come with needs of the human to improve the production efficiency,and to reduce the labour intensity,it have enriched the material wealth of human beings.With the improvement of the living standard of the humans,the robots are hoped to walk into the life of the human,bringing something new to the daily life and entertainment.However,before the robot being a member into the household,there still have been several important problems which is the security in the process of interaction between human and robots,the environmental adaptability and the energy efficiency for work.The joint actuator is the key unit to realize the motion of the robot,and the keypoint to resolve the problems above.About the designment of the actuator,there yet is a strong applicable design method of compliant actuator which can match various application.Based on the principle of bionic antagonism to achieve compliance,this article will discuss and design a joint actuator with variable stiffness.Then it will show the safety of the variable stiffness actuator in a view of the stiffness characteristic.The specific work content was organized as follows:Firstly,the researching background and significance of the compliant actuator was described,and explained the concept of the compliant actuator briefly.Then,the induction and classification of the realization method of compliance was given,and show the research status both at home and abroad.Secondly,the implementation of compliant actuator based on the antagonism was established,and took a further analysis on the principle of stiffness forming of the compliant actuator,then deduced mathematical model of the variable stiffness actuator;With the method of variable control,the influence factors which affect the static stiffness characteristics of the driver are analyzed in theory by utilizing mathematical tool of analysis on the MATLAB,then several design parameters of the prototype was given.Thirdly,according to the calculation and checking of the drive motor,synchronous belt transmission,elastic element,the RX-28 and other main components were selected.The accurate stiffness mathematical model of the compliant actuator based on antagonism is established according to the related parameters.Based on the mathematical model,the static stiffness characteristics with no-load or static load on the actuator were analyzed.Then,with the method of the Lagrange,the kinetic analysis of the variable stiffness actuator was given,and obtained the kinetic equation of the system.Meanwhile,it also established antagonistic SEA model and the mathematical model of the driving motor respectively,and had set up simulation models in the Simulink respectively.Finally,We have the analysis of the antagonism actuator about the control stategy,studied the position control,stiffness control,decoupling control strategy of the position and stiffness with PID control method;Simulation experiments were designed in Simulink,and studied the dynamic performance of the actuator with the above-mentioned control strategy,the results showed that the variable stiffness actuator could effectively track the sine wave,and had a certain accuracy;The variable stiffness actuator could effectively drive back when a external torque was given,showing certain security.The experimental prototype of the variable stiffness based on antagonism was developed,which was used for the experiment and research,to verify the theory analysis and simulation results.