Irreversibility modeling applied to the control of complex robotic drive chains

The phenomena of static and dry friction may lead to difficult problems during low speed motion (e.g. stick slip phenomenon). However, they can be used to obtain irreversible mechanical transmissions. The latter tend to be very hard to model theoretically. In this paper, we propose a pragmatic approach to model irreversibility in robotic drive chains. The proposed methodology consists of using a state machine to describe the functional state of the transmission. After that, for each state we define the efficiency coefficient of the drive chain. This technique gives conclusive results during experimental validation and allows reproducing a reliable robot simulator. This simulator is set up for the purpose of position control of a medical positioning robot.