Time-optimal control of semi-passively actuated closed-loop chain robots

Paper in proceeding, 2002

The controlled motions of a new structure of closed-loop chain robots with different degrees and types of actuation are under the study. An optimization approach has been used to investigate the advantages of using overactuation and unpowered spring-damper-like drives for the robots performing pick-and-place operations. Solution of several variants of a time-optimal control problem has been obtained for considered semi-passively actuated robots. Emphasis is put on the study of interaction between the controlling stimuli of powered drives and the torques exerted by unpowered drives needed to provide time-optimal motion of fully actuated and overactuated robots. Analysis of simulation results has shown that the quickness of the robots performing pick-and-place operations can be considerably increased due to overactuation and optimal dynamic interaction between powered and unpowered drives. Obtained results can be used for optimization of performance of robotic systems.