Study On Dynamic Response Characteristics Of The Planar Biped Robot Under Randomly Uncertain Disturbance

This dissertation is combined with the National Natural Fund Project ’Multi-source random uncertainty modeling,intelligent control and dynamic simulation experiment on biped robot’(No.11372270),and focuses on the dynamic response characteristics of the planar biped robot under randomly uncertain disturbance:the hybrid dynamic modeling method and control modeling method of the planar biped robot under randomly uncertain disturbance were separately studied;randomly uncertain disturbances in driving joints of the planar biped robot induced by randomly uncertain parameters and joint frictions as well as the other factors were separately analyzed;based on the robotic hybrid dynamic model,the dynamic response characteristics of the planar biped robot controlled with OL method under randomly uncertain disturbance were studied;the planar biped dynamic response characteristics under randomly uncertain disturbance were optimized with proposd BPNN-HZD and SVM-HZD methods.The research contributes to the theories and methods of the robotic dynamic response characteristics,and the planar biped dynamic response characteristics under randomly uncertain disturbance were improved evidently,which has great significance for the robotic stable walking.This study is organized as follows.(1)The hybrid dynamic modeling method and control modeling method of the planar biped robot under randomly uncertain disturbance were separately studied.The model hypothesis and walking hypothesis of the planar biped robot,as well as Taguchi orthogonal method for multi-sources randomly uncertain factor combination were given.The biped robotic hybrid dynamic model under undisturbed situation or randomly uncertain disturbance was separately derived by referring Lagrange method.OL method,HZD method,and the feedback control method with disturbance compensator were separately given and proposed for controlling the biped robot walking.All of the above theories are the basis of studying the biped dynamic response characteristics under randomly uncertain disturbance.(2)The randomly uncertain disturbances in the planar biped robot were studied.The hybrid dynamic model of the planar 5-link biped robot with randomly uncertain parameter was built,the randomly uncertain disturbance induced by single or multiple randomly uncertain parameters was separately studied by employing Monte Carlo method and Taguchi orthogonal method.The conclusion can be summarized from simulation experiments:according to the evaluation indexes of the randomly uncertain disturbance,the randomly uncertain parameters are classified into three categories,i.e.,strongly sensitive,sensitive and almost insensitive parameters,where strongly sensitive parameters can generate much bigger randomly uncertain disturbance than the other parameters.The randomly uncertain disturbances from joint frictions and electromagnetic interference were separately studied.The simulation result shows the direction of the randomly uncertain disturbance from joint friction is altered along to the joint velocity,in addition,electromagnetic interference can induce continuous or intermittent randomly uncertain disturbance.In order to reduce randomly uncertain disturbance,some measures should be taken to restrict the factors that can cause randomly uncertain disturbance,and then the robotic dynamic response fluctuation will be reduced.(3)The dynamic response characteristics of the planar 5-link biped robot controlled with OL method under the randomly uncertain disturbance were studied.The forward dynamic model of the planar 5-lins biped robot was constructed.Then ideal torques were merged with three different category disturbances,i.e.,periodic disturbances,pulse disturbances or randomly uncertain disturbances,and separately input into the biped joints with OL method to obtain the robotic dynamic response,and the robotic dynamic response characteristics were analyzed.The study result shows that the robot will has greater fluctuation when disturbances loaded on the knee and hip joints of support leg,the hip joint of swing leg.The outputs of hip and knee joints of swing leg are more sensitive than the other joints.The robot will gradually deviate from the preset gait trajectory when the large randomly uncertain disturbance is input,therefore on one hand the above sensitive input and output variables need accurately monitor,on the other hand the feedback control method applies to randomly uncertain disturbance should be proposed to optimize the biped dynamic response characteristics.(4)A BPNN-HZD method was proposed,and the dynamic response characteristics of the planar biped robot with simple structure were optimized by the method.The hybrid dynamic model of a planar 3-link biped robot was built,and the dynamic response characteristics of the robot controlled by HZD method under undisturbed situation and randomly uncertain disturbance were separately studied.The disturbance compensator was constructed based on BPNN,and a novel BPNN-HZD method was developed,the dynamic response characteristics of the biped robot controlled by the above proposed feedback control method under randomly uncertain disturbance were studied.The simulation results show that the angle and angle velocity between the robot trunk and the coordinate are much more sensitive than the other variables;the robotic angle of each joint is continuously fluctuated while the angle velocity of each joint is with instantaneous mutation under the randomly uncertain disturbance.The BPNN-HZD method has strong capability to deal with randomly uncertain disturbance,by which the dynamic response characteristics of the robot with simple structure can be effectively optimized.(5)A SVM-HZD method was proposed,and the dynamic response characteristics of the planar biped robot with relatively complex structure were optimized by the above method.The hybrid dynamic model of a planar 5-link biped robot was built.A disturbance compensator was constructed based on SVM,and a novel SVM-HZD method was proposed to optimize the robotic dynamic response characteristics.Under the randomly uncertain disturbance the biped robot was separately controlled by the HZD method and SVM-HZD method,their dynamic response characteristics were separately studied.The simulation result shows that the angle of support leg knee joint,as well as the angle between the trunk and the coordinate are much more sensitive than the other variables under randomly uncertain disturbance;the biped angle of each joint is continuous fluctuated while the angle velocity of each joint is instantly changed under the above situation;the SVM-HZD method shows better disturbance compensation result in real time than the HZD method,and then the dynamic response characteristics of the robot with relatively complex structure can be effectively optimized.