Design of a holonomic omnidirectional vehicle

A novel design of a holonomic omnidirectional vehicle is introduced. The holonomic mechanism allows the vehicle to maneuver in an arbitrary direction from an arbitrary configuration on a plane. This significantly simplifies control problems and improves positioning accuracy. A fundamental method of obtaining omnidirectional motion with holonomic constraints with the floor, using a mechanism with spherical tires, is presented. Kinematic analysis of this mechanism gives the vehicle Jacobian relating actuator velocities to the vehicle velocity components. Analysis of lateral tire slip during vehicle rotation allows slip reduction methods. A prototype vehicle using this special mechanism and a computerized control system is designed and tested. In addition to rotation, the vehicle can perform very accurate translational motions, in two orthogonal directions, arbitrarily termed forward and sideways. Motions in these two degrees of freedom are decoupled from each other and are insensitive to variations in ground friction coefficient.<
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