FROM IDENTIFICATION TO MOTION OPTIMIZATION OF A PLANAR MANIPULATOR

Identification of inertia constants and joint frictions of a robot man ipulator is achieved in situ, without dismantling operations, by means of specific test motions. The necessary estimation of actuating torqu es is carried out by measuring, with Hall effect transducers, the curr ent absorbed by the motors which power the system. This identification is accomplished by using a precise methodological order adapted to a planar SCARA type manipulator with two degrees of freedom. The identif ication of friction laws underscores a hysteresis phenomenon of the di ssipative torques. This indicates that friction doesn't result from a simple superposition of a dry friction law and a viscous damping law. The identification results were applied with success to implementation of optimized trajectories computed on the basis of a dynamic criterio n. The effective minimization of the performance criterion along the o ptimized trajectories, according to the corresponding standard traject ories, was verified experimentally by evaluating the motor work and ac tuator torques.