Nonlinear backstepping design of robot manipulators with velocity estimation feedback

In this paper, the nonlinear backstepping design controller with a velocity observer is proposed for the trajectory tracking control of robotic manipulators. Most robot manipulator controllers require position measurements as well as velocity measurements to achieve their control goals, but a lot of robotic systems do not have the velocity measurement devices. Therefore, a velocity observer is employed to estimate the unknown angular velocity of robot manipulators, and then the nonlinear controller based on backstepping design algorithm is developed for the robot manipulator systems. The proposed controller is not only to stabilize the robot system, but also to drive the trajectory tracking errors to converge to zero rapidly. Furthermore, some simulation results are given to illustrate the excellent performance of the backstepping control design scheme applied to a two-link robot manipulator.