A Novel Hybrid 3-RPR Mechanism With Scalable Platforms for Self-Crossing Locomotion

To investigate novel mobile robots is still of its fantasy. In this paper, we proposed a novel hybrid 3-RPR mechanism with scalable platforms for self-crossing locomotion. The hybrid mechanism is constructed by replacing the lower and upper rigid platforms of over-constrained 3-RPR parallel mechanism (PM) each with a scalable planar 3P mechanism. Through the contraction and expansion of the two scalable platforms, the mechanism can achieve a novel locomotion, which is called self-crossing locomotion (SCL). By actuating three limbs, the mechanism can also achieve inchworm locomotion and combined locomotion of SCL and inchworm locomotion. The mobility and kinematic analysis of the mechanism are then dealt with. As a demonstration, the pipe-climbing gaits with the above modes of locomotion are planned. According to the gaits analysis, the mechanism can adapt to a wide range of pipe diameters and overcome bigger fracture in pipe. The specific mechanical design is introduced and the prototype is fabricated to verify the feasible of the mechanism.