Cascade Sliding Mode Control for Bicycle Robot

The nonlinear characteristics in the bicycle robot dynamic system make the bicycle robot control much more difficult. Aiming at this problem, the cascade sliding-mode control method was applied to the bicycle robot nonlinear system. A kind of bicycle robot nonlinear dynamic model presented based on Lagrange method was analyzed and the cascade sliding-mode controller of multi-sliding surface was designed with the method of variable structure control theory. This method divided system states into two sub-systems. Firstly, two state variables of subsystem are chosen to construct the first-layer sliding surface, on the basis of the first-layer sliding function, the first layer sliding surface and one of the residual state variables are used to construct the second-layer sliding surface, at last, all of the system states are included in final sliding surface. The ultimate control is obtained by using Lyapunov stability theorem. since each sub-sliding surface contains the equivalent components of sliding surface, which makes the system states move along the each sub-sliding surface. The cascade sliding-mode controller has the bicycle robot controlled effectively, which has been verified in the simulation experiment.