Architecture and trajectory constraint control of a five bar Cobot

Cobot (collaborative robot) doesn´t have any motive power of its own, so it can do direct collaborative work with a human operator in a shared workspace. In this paper a five bar Cobot and its trajectory constraint control strategy are presented. The Cobot uses two new CVTs (continuously variable transmissions) that are connected in parallel mode, which are separately installed on the two base joints of the Cobot. The CVT is composed of two DC motors, two unilateral over-running clutches and so on. The constraint control of the Cobot endpoint trajectory was implemented by regulating the speed of each CVT. In addition the trajectory constraint control strategy involves in actual position, speed of the Cobot endpoint and the force applied by a human operator. An experiment prototype of Cobot was developed, and the experiment results show that the Cobot architecture and the trajectory constraint control strategy are feasible.