Abstract: Aiming at the problem of motion stability of the redundantly actuating mechanism caused by uneven load, one scheme of the redundantly actuating mechanism is proposed. The position, velocity and acceleration equations are established on the basis of geometric constraints, and the dynamical model is established based on the principle of virtual work. Then, the stability of this mechanism is analyzed by use of the Lagrange theorem and the Lyapunov stability principle, and the relationship between bending angle of the coordinate link and stability is obtained. The correctness of the analysis is proved by an example study, which is analyzed by use of the method of phase plane and the analysis of uneven load ratio of the driving cylinder. The results demonstrate that this mechanism under offset load causing by perturbation keeps stable by self-coordination, and has the trend of backing to even load, only if the bending angle of the coordinate link is larger than 180 degrees.

Key words: Motion stability, Redundant actuator, Uneven load