Maximum Load Carrying Capacity of a Hybrid Robot Considering Tip-Over Stability

Mobile robots due to their wide range workspace are important and are widely being investigated. In this paper, determining the maximum load carrying capacity of a novel mobile manipulator for a specified path of end-effector is elaborated. The limitations on the maximum load are joint actuator capacities and stability of robot against tipping-over. One of the most important problems caused by mobile robots is the instability problem or tipping-over. This phenomenon can happen when mobile robotic system manipulates a heavy object. The introduced system compounds of differentiallydriven wheeled platform, a novel spatial parallel mechanism, and serial manipulator arms. Using parallel mechanism as base for serial manipulator cables the system to carry heavy loads and cables the system to prevent tipping-over. Spatial parallel mechanism is three degree-of-freedoms (DOF) and a Cartesian workspace and uses three planar prismatic actuators along linear axes. In this paper, kinematic and dynamic of proposed robot is investigated. Exerted holonomic and nonholonomic constraints on the system are determined. Also tip-over stability of robot will be investigated using Moment Height Stability (MHS) measure. This robot is able to compensate tip-over instability and thus can be able to carry more heavy objects. In this work it is assumed that the load is rigidly grasped by the end-effector. An algorithm is developedto find the maximum payload on a specified path considering several limitations. It is shown that the motion of robot is stable. The optimum load is solved base on the direct solution.

کلیدواژه ها:

mobile robot ، maximum load ، MHS ، tipover