Research On Motion Control Of Hopping Robot Based On Nonlinear Stability Analysis Method

Hopping is the basis of leg motion.In the design of complex multi legged robot system,the single legged motion state is often studied first.For the single legged robot,there is only hopping motion state.Therefore,the hopping motion performance and motion control are the key directions of research.In the related research results of leg type robot's hop height control,most of them rely on mechanical structure design,adding sensors,signal processing and other technical means to realize the robot's touchdown judgment and motion state detection,so that the motion control algorithm can adjust the control output in different stages of the hop to deal with the problem of robot's hop from motion Form itself or the mechanical system caused by nonlinear,high dynamic,force feedback control and other problems,but this undoubtedly increases the workload of mechanical design and the complexity of motion control algorithm.Aiming at the existing problems in the field of hopping robot,this topic focuses on the design method of advanced motion controller,optimization of robot body structure design,research from two aspects of electro-hydraulic driving hopping robot body design and nonlinear model construction,hopping robot motion control development based on nonlinear stability analysis method,to provide the basis for later experiment and simulation Foundation.Aiming at the problem that the existing height controller of jumping robot needs to detect the ground contact by measuring multiple state variables,a new self-excited oscillation controller is developed in this paper.The controller consists of a force positive feedback loop,a nonlinear link,a position feedback loop and a velocity feedforward loop.By using the description function method,the criterion of the stable self-excited oscillation motion of the system is derived theoretically,and the stability of the typical nonlinear links(such as saturation characteristic,dead time characteristic,relay characteristic and dead time relay characteristic)is judged and the hop height control mechanism is studied.This paper analyzes the function mechanism of the main components of the hydraulic system,introduces the nonlinear factors,and establishes the nonlinear mathematical model of the hydraulic system.Using Autodesk Inventor and Matlab/SIMULINK for CO simulation,the virtual prototype of the hopping robot is built in Sim Mechanics,and the visual modeling of the robot is completed.By analyzing the material of the ground,the mechanical relationship model between the ground and the robot body is established by using the spring damping system.Finally,the feasibility of the controller is verified by the robot prototype experiment,and the nonlinear model is modified combined with the experimental data.