Over-rated drive of robots and its evaluations

Abstract

The purpose of this study is to reexamine and expand the concept of the ratings of machines to flexibly apply it to quickly driving of robots by over-rated drive. The actuators, especially electrical actuators such as DC servo-motors are much inferior to human muscles in view of power rate or power per weight by 10−2 based on the fundamental calculations shown by our research group. Robots with electrical actuators can handle a big and heavy object, e.g., with 50kgf, but the motors utilized are inevitably sure to be big and heavy ones, and the world it can work is restricted.One method to solve such the problem is to make actuators deliver more output over its conventional ratings. The ratings, e.g., rating for output, for voltage, for current, etc., are conventional for steady operation for long hours. For short-time and careful use, some over-rated operation can be applicable to electrical motors as human muscles. We human sometimes work hard in all their energies in their muscular labor. They deliver the power in short period, become tired and then take a rest, if necessary. Similarly a DC motor can deliver the torque of three times of the rated torque by being given the over-rated current of three times under the condition of the operation period, the allowable maximum instantaneous current, etc. The ratings and over-rated drive to give robots quick motions for short-period operations have connectedly been discussed.