Abstract: For configuration transforming, configuration keeping and working sequence problems of practical constrained metamorphic process, a concept of equivalent resistance gradient of metamorphic joints is proposed so that the control of constrained metamorphic processes is transformed into the regulating of the corresponding metamorphic joints to investigate a new way for constrained metamorphic metamorphic mechanisms design. By introducing a kinds of metamorphic cyclogram, the relationship bewtten task-based kenimatic rules and constrained forces/torques of the metamorphic joints can be obtained. A non-dimension equivalent resistance of metamorphic joints and the equivalent resistance gradient model of metamorphic mechanism are defined via the equivalent of the constrained force and the torque. The connectionships of equivalent resistances, constraint charecteristics and forms, and the structures of metamorphic joints in the working stages are revealed. The design approach is demonstrated based on the metamorphic cyclogram and the equivalent resistance gradient model for a broken strands reposition metamorphic mechanism of the repair robot for extra-high-voltage power transmission lines. The results show that proposed design theory and method are available and practical.

Key words: constrained metamorphic process;configuration regulating;equivalent resistance gradient;matamorphic cyclogram