RESONANCE FREE MECHANICAL MANIPULATORS

MRAIC schemes have been proposed as an on-line vibration test-ing method for the identification and control of the dynamic characteristics of mechanical manipulators. The idea behind the method is to make use of input-output sampled time response data such as acceleration, velocity, or displacement at stations on the manipulator to determine the unknown natural frequencies and associated viscous damping ratios. The analy-sis procedure is based on the construction of a stochastic model for the manipulator from the experimental response data. A re2rence model with an acceptable dynamic behaviour is then defined and the mechanical manipulator is forced to track this model using an MRAC algorithm. Also included in the analysis is a study of how to optimize the effects of different parameters introduced in the method of control, such as the starting value of the adaptation gain, the rate of decreasing this gain, and the ratio of the proportional to integral gain at each step. The simulation study shows that the technique works, in principle, for manipulators when a finite number of modes are included in the response. The results obtained from the present investigation have indicated that the proposed method is ad-equate and not sensitive to ueasurement noise or round-off errors.