Abstract
A hybrid parallel/serial manipulator architecture is introduced where the translational freedoms are provided by a cable-direct-driven robot (CDDR) and the rotational freedoms are provided by a serial wrist mechanism. The motivation behind this work is to improve the serious cable interference problem with existing CDDRs and to avoid configurations where negative cable tensions are required to exert general forces on the environment. Only the translational CDDR is considered in this paper; including kinematics and statics modeling, and determination of the statics workspace (the space wherein all possible Cartesian forces may be exerted with only positive cable tensions). Examples are presented to compare the planar 3-cable CDDR with one degree of actuation redundancy and the 4-cable CDDR with two degrees of actuation redundancy. It was found that the 4-cable case requires less cable tensions and thus less energy compared to the 3-cable case in performing the same simulated tasks.
