Posture Control,Stability Designation And Fault Diagnosis Of Quadruped Robot Torso

In recent years,with the progress of science and technology as well as the innovation of robotic technology,people are gradually realizing the importance of developing legged robots.Therefore,in the past four decades,an increasing number of research institutes are focus on legged robots.Comparing to single-legged,bipedal and hexapod robots,quadruped robots are superior to the other three in terms of dynamic characteristics,fault tolerance and control complexity,and many current researchers are turning their focus to quadruped robots.At the same time,with the needs of robotic fault tolerance,the robot fault diagnosis work has become even more important.For quadruped robots,on the one hand,the importance is system stabilization as well as the robot's position and attitude control performance;on the other hand,for the complex robotic control systems,the key point is fault diagnosis and fault estimation,which carried out for system analysis and control strategy formulation.Therefore,this paper study's focuses on robot pose&position control and fault diagnosis&estimation.The main research contents are as follows:1.The Newton-Euler kinetic equation is written out for the robot system column.Taking the three-axis displacement and the three-axis rotation angle as the system state variables,a continuous time state space model is established.For the approximate discretization design of continuous-time system,we obtain the discrete-time state-space model.2.The output feedback controller and the optimal controller based on LQR are designed for the previous state-space model,so that the system output can follow the reference input quickly and the stability of the system can be judged by the Lyapunov stability criterion.The numerical simulation of the designed controller shows that the output feedback controller and the LQR-based optimal controller can control the robot well and quickly follow the reference input.At the same time,the optimal controller based on LQR has some fault tolerance.3.For systems with faults and disturbances,we use the Parity-Space approach to design the residual generator and the fault estimator.The residual obtained by the residual generator can diagnose the system faults.Combined with the designed fault alarm thresholds,the system faults can be punctually and effectively alarmed.The system fault estimates obtained by the fault estimator can realize the fault identification,which laid the foundation for the formulation of the advanced control strategy plan.We conducted numerical simulation of fault diagnosis and fault estimation.The results show that the residual generator and fault estimator designed in this paper can accurately and effectively alarm the system fault and estimate the fault.4.We summarized the main work and shortcomings of this article,and carried out the prospect of the next step.