The Mobility and High Load-to-weight Ratio Oriented Design Criteria of Hybrid Robots

To solve the problem of hybrid mechanism design with mobility and high load-to-weight ratio constraints, this paper presents a design criterion for the hybrid robots, namely Mobility and High Load-to-weight Ratio(MHLWR)Oriented Design Criteria. Firstly, a new concept, the unit power concentration vector, which represents the anisotropy of power transmission, is proposed. And then, the kinematic model of the mechanism is established based on the screw theory. Thirdly, the unit power concentration vector of the hybrid robot is derived in the configuration space. Finally, an evaluation index is defined as the maximal ratio between unit power and power density. The MHLWR design criterion requires the designer to minimize this ratio by designing the configuration to increase the power density. Based on this criterion, a 5 DOF hybrid robot with a high load-to-weight ratio is developed to replace faulty insulators in the substation. Many experiments have been implemented, and the simulation and experimental results show that the MHLWR design criterion is correct and valid.