Inverse kinematics of binary manipulators with applications to service robotics

Binary actuators have only two discrete states, both of which are stable without feedback. As a result, manipulators built with binary actuators have a finite number of states. The major benefits of binary actuation are that extensive feedback control is not required, task repeatability can be very high, and two-state actuators are generally very inexpensive, resulting in low cost robotic mechanisms. These manipulators therefore have great potential for use in the service sector, where the cost of standard, high performance, robotic manipulators is often difficult to justify. A binary manipulator by contrast, provides good performance, and is also relatively inexpensive. The most difficult challenge with a binary manipulator is to control it efficiently. Given that the number of configurations attainable by binary manipulators grows expotentially in the number of actuated degrees of freedom, calculation of inverse kinematics by direct enumeration of joint states and calculation of forward kinematics is not feasible in the highly actuated case. This paper presents an efficient method for performing binary manipulator inverse kinematics based on a continuum approach.