Actuator

Abstract

An actuator and control algorithm which provide an operator with the ability to intuitively and responsively maneuver heavy work-pieces with ease and precision. The structure of the apparatus may provide a hoist with a compliant sensing system to measure the weight of the payload. The compliant sensing system may result in smaller dead-bands than are realizable with traditional force sensing methods. At the command of the user, the control algorithm may switch between two distinct operational modes: float mode and manual mode. In float mode, the hoist actively counterbalances the weight of the load, allowing it to feel substantially weightless in the operator's hands. The operator can apply forces directly to the payload to accelerate it in the desired vertical direction. Because of the small dead-band realized with compliant sensing, the payload may be highly responsive to the operators force inputs. As a result, the payload may be intuitively maneuvered at very high speeds, as well as very low speeds. Alternately, the operator may choose to operate in manual mode. While in manual mode, the hoist operates like traditional lifting hoists, responding to velocity commands issued from a remotely controlled pendant.