Capaciflector collision avoidance sensors for robots

Abstract A state-of-the-art capacitive proximity sensor is being developed by NASA for robot collision-avoidance. The “Capaciflector” ( Capaci tive Re flector ) uses a simple extension of an instrumentation technique for controlling stray capacitance. In this instance a capacitive sensing element, backed by a reflector driven at the same voltage as, and in phase with, the sensor, is used to reflect the field lines away from the grounded robot arm towards the intruding object, thus dramatically increasing range (greater than 12 in. with the reflector/one without) and sensitivity. The stand-off distance of this system from the grounded robot arm is essentially zero. In this paper the present status of sensor development is described to include the basic workings of the sensor charges and fields, the electronic circuitry and mathematical modeling. Test results are given.