| The existing walking robots can be divided into biped,quadruped and six-foot robots according to the number of legs in which biped robot complex dynamic system with multi-variable,nonlinear,strong coupling and variable structure.It has small number of legs and flexible structure,but due to the limitation of the number of legs,stable control during the walking process is a problem to be studied.The inverted pendulum is a simplified model of many complex and uncontrollable objects.It is an experimental device for ideal verification algorithm in automatic control theory,and also a means to study stability control.At the same time,the walking robots can be divided into series and parallel leg mechanisms according to the form of legs,and the parallel mechanism is used as legs of the robot,which has higher bearing capacity.The inverted pendulum based on the parallel platform is used to simulate the parallel biped robot and the stability control problem can be studied.Based on control theory of the inverted pendulum,the 3-RPC parallel leg mechanism is selected as the leg of a biped robot,which is simplified into the inverted pendulum model based on the parallel platform.The main research contents are as follows.Starting from the basic research of the inverted pendulum,the PID and LQR controllers are designed and the virtual reality model is used to realize the MATLAB/Adams co-simulation based on the state space model of linear inverted pendulum.State equation simulation is performed by model predictive control.The control effects of the three control strategies are compared and analyzed,and the PID method with better control performance is applied to the more complex planar inverted pendulum.The co-simulation of MATLAB/Adams is realized to achieve stable control and anti-interference control.According to the designed PID control strategy,a linear inverted pendulum experiment was carried out.The stability control experiment and anti-interference experiment are carried out,and the balance control of the pendulum were realized.The results show that the designed method has good control effect in the control of linear inverted pendulum.The 3D model of 3-RPC parallel leg mechanism is established,and its kinematics analysis and workspace analysis are carried out.The theoretical analysis results of the simulation software are discussed to verify the feasibility of the mechanism as a robotic leg mechanism.The changes of speed and acceleration of the leg mechanism are analyzed.The statics research of the leg mechanism is carried out by using finite element software.The dynamic model of the 3-RPC PM is established by virtual work principle.Then the dynamic model is verified by the co-simulation method.The analysis results show that the 3-RPC parallel mechanism can meet the walking requirements of the biped robot.The stability control method is analyzed and the inverted pendulum system model based on 3-RPC parallel mechanism is simplified,then the simplified system model is obtained.The T-S fuzzy model and PID simulation is used for control analysis to achieve stable control.The simulation results are compared.The dynamics and kinematics control strategies of 3-RPC parallel mechanism is discussed.The position feedback is selected for control,and the co-simulation is realized by PID method. |
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