Abstract: A kind of single-DOF mobile mechanism is proposed based on an over-constrained spatial deployable linkage. According to the analysis of motion principles, there are two types of gaits, which are orientation definite gait and orientation random gait. In the orientation definite gait, the orientation of movement of the mechanism is definite, while in the orientation random one the stochastic variable of orientation obeys the Bernoulli distribution in ideal condition. Based on the mobile characters and the path, the controlling method for the mobile mechanism is demonstrated to realize either destination movement in a two dimensional environment. The dynamics model of the mobile mechanism is built and simulated. The results of the simulation prove that the mobile mechanism can move to any destination area from a given starting area in a plane by compound control of the two kinds of gaits. A prototype is manufactured and the theory is demonstrated by its performance.

Key words: Bernoulli distribution, Closed-loop linkage, Mobile mechanism, Over-constrained linkage