Design and analysis of a new haptic device using a parallel mechanism

Presents the design and analysis of a 6 degree-of-freedom new haptic device for interfacing with virtual reality by using a parallel mechanism. The mechanism is composed of three pantograph mechanisms that are driven by ground-fixed servomotors and stand perpendicularly to the base plate, three spherical joints between the top of the pantograph mechanisms and connecting bars, and three revolute joints between connecting bars and a mobile joystick handle. Forward and inverse kinematic analyses have been performed and the Jacobian matrix is derived. Performance indices such as GPI (global payload index), GCI (global conditioning index), translation and orientation workspaces, and sensitivity are evaluated to find optimal parameters in the design stage. The proposed haptic mechanism has better load capability than those of pre-existing haptic mechanisms due to the fact that motors are fixed at the base. It has also wider orientation workspace mainly due to a RRR type spherical joint