Generic model control (GMC)

An explicit solution for the robot arm controller, optimal in the linear quadratic sense, is obtained. Based on this formulation, a PID controller with acceleration feedback is proposed which is computationally efficient and robust relative to variations in the dynamic model and external disturbances.

L-Q design of PID controllers for robot arms

In this paper, the robustness of the computed torque technique for manipulator control is investigated in the presence of model errors. The robustness analysis is performed in the frequency domain by means of the block Gerschgorin theorem. The block Gerschgorin theorem gives inclusion regions for the eigenvalues of the linearized state space model. The stability of the system close to a trajectory can then be investigated. The results indicate that relatively large errors in the nonlinear feedback compensation of system nonlinearities may be tolerated without affecting system stability. However, even small errors in the computed inertia matrix may result in instability.

/pdf/on-the-robustness-of-the-computed-torque-technique-in-9y8hce681p.pdf

On the robustness of the computed torque technique in manipulator control

The artificial potential method of constrained robot control is presented. The method does not imply knowledge of a detailed robot model and, nevertheless, makes it possible to drive a robot in the environment with obstacles of any shape and along a desired trajectory as well as to take into account constructive constraints. The method is based on the construction of an artificial potential that provides the absence of intermediate equilibriums in which the robot can be locked.

Artificial potential method for control of constrained robot motion

Generic model control — theory and applications

An optimal control formulation for robotic manipulators is proposed in this paper. The Computed Torque Control, Resolved Acceleration Control, and a PID End Point Control are derived as special cases of this formulation. Torque and acceleration feedback are adopted to eliminate the on-line calculations of feed forward components in the above control algorithms, and to increase robustness of the control system. This controller can be implemented approximately without torque sensors and accelerometers. The resulting control system is proved to be bounded input bounded state stable. Simulation results on both the Scheinman MIT and PUMA 600 arms are presented.

G. Saridis

Papers

Optimal/PID formulation for control of robotic manipulators