Uncalibrated Visual Tracking Control without Visual Velocity

Hesheng Wang, Yunhui Liu

Abstract: This paper presents a new adaptive controller for dynamic tracking of a robot manipulator without visual velocity when the intrinsic and extrinsic parameters of the camera are not calibrated. Most controllers in the past require the measurement of the visual velocity or differentiation of the visual position. The measurement of the visual velocity is subject to big noises in general due to low sampling rates of the vision loop. To avoid performance decaying caused by measurement errors of the visual velocity, the controller we developed requires estimated visual velocity only. With a full consideration of dynamic responses of the robot manipulator, we employed the Lyapunov method to prove the convergence of the image errors of the trajectory to zero and the convergence of the estimated parameters to the real values up to a scale. Experiments have been conducted to demonstrate good convergence of the trajectory errors of the robot under the control of the proposed method