In this paper, an innovative mobile platform is presented which is equipped by three new wheels. The core of the new idea is to establish a new design of rigid circular structure which can be implemented as a wheel by variable radius. The structure of wheel includes a circular pattern of a simple two-link mechanism assembled to obtain a wheel shape. Each wheel has two degrees of freedom. The first is to rotate wheel axis and the second is to change the wheel radius. As the first step, after definition of the new model, its spatial kinematics and constraints will be formulated. The well-known Newton-Raphson algorithm is implemented to find the current response of the kinematic model. A semi-dynamic formulation is further utilized to find the torque of motors for adapting the required wheel radius for maneuverability improvement on rough surfaces. The principles of virtual work will be used to extract the torque values numerically. The ability of the proposed robot for performing the required tasks will finally be checked by some simulations.
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