Research On Dynamics And Control Of A Class Of Switching Nonholonomic Constrained Robots

Switching non-holonomic constrained robotic systems is a special kind of hybrid system with essential nonlinear characteristics.In the field of robotics,non-holonomic constraints exist widely in wheeled mobile robots,flexible manipulators,artificial satellites,space shuttles and other mechanical systems and have the characteristics of rolling contact,angular momentum conservation,and constrained changes in the working process with preferable environmental adaptation.This paper studies the dynamics and control of a dual-mode non-holonomic constrained system from the perspective of non-holonomic constraints,aiming at solving the switching control problem of a class of dual-mode robots with nonholonomic constraints.Taking the dual-mode "Wheel and Quad-rotor" robot as an example,established respectively single-mode dynamic model and transformed into a differential flat system form.The dual mode switching control is implemented in the differential flat space,and then the inverse differential flat is transformed back to the state space to solve the switching control problem.Taking the single-mode non-holonomic constrained system,wheeled mobile robot as an example,solved the motion planning and trajectory tracking problems from the perspective of differential flatness.Firstly,the coordinate transformation is carried out to obtain the affine form of double input.According to Lyapunov stability theory,realized the finite-time stable control design.Then,according to the nonholonomic constrained robot with flatness,proposed a motion planning method with redundant undetermined parameter polynomial and based on the generalized matrix theory to solve the redundant parameters,then pointed out that the optimal motion planning under certain evaluation indexes can be achieved.Finally,designed the sliding mode variable structure control for the single mode differential flat type to achieve the position and speed tracking of the ideal trajectory.Based on the single-mode control design,the virtual input control design for the differential flat form of the dual-mode "Wheel and Quad-rotor" robot is finally implemented,according to the linear switching control theory,designed a slow switching control with state feedback The device realizes the slow switching control of the "Wheel and Quad-rotor" dual mode.Numerical simulation results are given for each control design,and the results show the feasibility of the control design.