Haptic Device Using a Newly Developed Redundant Parallel Mechanism

A number of haptic devices have recently become available on the commercial market, and these devices are becoming common not only in research but in consumer use as well. In this paper, a new parallel mechanism, referred to herein as DELTA-R (meaning DELTA-Redundant, formerly referred to as DELTA-4) is proposed for a new haptic device having high-quality force display capability and operability. DELTA-R allows three-degree-of-freedom (DOF) translational motions. The key features of DELTA-R, as compared with conventional parallel mechanisms, are redundant actuation, a smaller footprint, a larger working area, and improved access to the end effector. The prototype is equipped with a 3-DOF rotation mechanism, the center of motion of which is located on the wrist position of the operator. An evaluation test of the force display was conducted using a prototype of the proposed mechanism. This paper describes the kinematic design, kinematic modeling, kinematic analysis, prototype implementation, and evaluations.