A known prosthesis comprising parts which are movable relative to oneanother, by way of an actuator and a control, offers more than one kind ofmovement, positioning the movable parts in a known reference position, such asafully open position, before applying appropriate power to the movable parts toeffecta further movement, which may result in energy being wasted whilst it is firstmovedinto the reference configuration. Changes in frictional forces over time mayresult inerror.Accordingly, the present invention is directed to a prosthesis in which amovement transducer is connected to a control and also to an actuator toprovidesignals to the control indicative of the amount of movement between two partsof theprosthesis effected by the actuator, and the control operates the actuator independence upon the signals it receives from the transducer.
