Biped 4-UPU Parallel Mechanism

A novel biped robot based on a 4-UPU (universal-prismatic-universal) parallel mechanism with actuation redundancy is presented. The biped robot consists of two platforms and four UPU serial chains as limbs. The actuation method of the mechanism is determined based on the mobility and singularity analysis. The singular positions of the mechanism are identified and then eliminated using a redundant actuator. To meet different requirements, the multiple motion modes of the robot are discussed and simulated in the gait analysis. Moreover, the robot has special gaits for reset and self-rescue if overturned. Kinematic analysis of the mechanism and walking stability analysis are carried out in detail. Physical prototype experiments indicate that the proposed biped robot is feasible. Through properly planning the motion modes, the biped robot can quickly pass through rugged terrain containing slopes and obstacles.