Experimental and Theoretical Analysis of a Uni-Drive Modular Robot: Design and Modeling

In this paper, the fundamental principals of design and modeling of so-called uni-drive modular robots are introduced. Lightweight modules are significantly important in the design and application of modular robots. This is achieved in this new class of modular robots by using a single base-mounted drive from which all joints tap power via a central rotating shaft using clutches. The clutches in the uni-drive modular robot are controlled using the pulse width modulation (PWM) technique. The position and velocity of the joints are regulated by controlling the engagement time of the clutches. The design of the mechanical drive unit is presented, with which this new design concept is implemented. The unit consists of two clutches to provide each joint with a bi-directional output while its input is uni-directional. For simulation purposes, a lumped parameter model for the selected type of clutch (spring wrap clutch) is developed. Finally, the experimental and simulation results for the fabricated and modeled mechanical drive unit are presented to show the feasibility of the uni-drive modular robot concept.