On the robustness of the computed torque technique in manipulator control

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.