A modified resolved acceleration controller for position-based visual servoing

This paper presents modifications to the resolved acceleration controller design to develop a Cartesian controller suitable for use with position-based visual servoing. The development of any Cartesian control for relative robot end-point position control with respect to an object, requires the solution to the problem of relative orientation measurement and control. This problem is due to the nonlinear nature of orientation and the complex transformations used for its representation. The solution proposed in this paper, is to use the orientation representation of roll-pitch-yaw angles in a vector form, and calculate the difference between the current vector and the desired vector to represent the orientation error. The Jacobian matrices which relate the roll-pitch-yaw rates to the joint velocities are developed. The resulting relationships are then used in the development of a modified resolved acceleration controller that is applicable to position-based visual servo control.