AN ASSISTIVE COBOT FOR AID IN SELF CARE ACTIVITIES

摘要

This paper reports on the design and development of a robotic device intended to assist persons with motor impairments. In the new design, assist is not offered in the production of motion of the user's limb, per the traditional approach using a robot configured as a powered orthosis. Rather, assist is offered in the determination of allowed motion, using the recently developed technology of cobots. A cobot is presented that is capable of guiding (but not producing) motions of the hand in a spherical workspace centered about an elbow resting on a table. Arbitrarily shaped paths embedded with the spherical workspace that feel to the user like guiding channels, say from soup bowl to mouth, may be programmed and user-selected. The cobot is able to produce forces perpendicular to the programmed path to suppress tremor or unintended involuntary movement while, by design, the cobot is unable to produce forces that oppose user motion in the intended directions (along the programmed path). The design of an assistive cobot is presented, and certain aspects of the mechanical and control design are discussed in detail. A numerical analysis and experimental characterization of rolling contact, which is elemental to cobot function, is outlined. Various advantages are expected to accrue from the application of cobots as assistive technology, given that the user remains in command of the basic production of motion.