An on-line parameter estimation scheme for generalized stewart platform type parallel manipulators

On line parameter estimation of a parallel manipulator is an important but difficult problem. The dynamic calculations for a parallel manipulator are lengthy and the direct kinematics cannot be solved in a suitable closed form. These two calculations consume a large amount of real time in an on-line estimator making its implementation difficult. In the present paper, the authors present a dynamic formulation technique for parallel manipulators which result in a parallelism in the dynamic equations of the above mentioned devices. This parallelism can be effectively utilized to reduce the computational burden of a controller which is equipped with parallel processors. The authors also present an on-line parameter estimation scheme in the present work where the time delay due to the direct kinematics calculation is reduced by employing a state predictor. The utility of the proposed scheme is established through simulation runs. Copyright (C) 1996 Elsevier Science Ltd