FAT-based adaptive visual servoing for robots with time varying uncertainties
ICRA'09 Proceedings of the 2009 IEEE international conference on Robotics and Automation
Dynamic visual servoing of a small scale autonomous helicopter in uncalibrated environments
IROS'09 Proceedings of the 2009 IEEE/RSJ international conference on Intelligent robots and systems
Brief paper: Adaptive Jacobian vision based control for robots with uncertain depth information
Automatica (Journal of IFAC)
Robotics and Autonomous Systems
Adaptive visual servoing using common image features with unknown geometric parameters
Automatica (Journal of IFAC)
Visual tracking control for an uncalibrated robot system with unknown camera parameters
Robotics and Computer-Integrated Manufacturing
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This paper presents a new controller for controlling a number of feature points on a robot manipulator to trace desired trajectories specified on the image plane of a fixed camera. It is assumed that the intrinsic and extrinsic parameters of the camera are not calibrated. A new adaptive algorithm is developed to estimate the unknown parameters online, based on three original ideas. First, we use the pseudoinverse of the depth-independent interaction matrix to map the image errors onto the joint space of the manipulator. By eliminating the depths in the interaction matrix, we can linearly parameterize the closed-loop dynamics of the manipulator. Second, to guarantee the existence of the pseudoinverse, the adaptive algorithm introduces a potential force to drive the estimated parameters away from the values that result in a singular Jacobian matrix. Third, to ensure that the estimated parameters are convergent to their true values up to a scale, we combine the Slotine-Li method with an online algorithm for minimizing the error between the estimated projections and real image coordinates of the feature points. We have proved asymptotic convergence of the image errors to zero by the Lyapunov theory based on the nonlinear robot dynamics. Experiments have been carried out to verify the performance of the proposed controller.