Control and design of the spherical pointing motor

TitleControl and design of the spherical pointing motor
Publication TypeConference Papers
Year of Publication1993
AuthorsBederson BB, Wallace RS, Schwartz EL
Conference Name, 1993 IEEE International Conference on Robotics and Automation, 1993. Proceedings
Date Published1993/05/02/6
ISBN Number0-8186-3450-2
Keywordsabsolute positioning device, Actuators, camera sensor, CAMERAS, Coils, electric actuators, electric motors, Magnetic field measurement, Magnetic sensors, Open loop systems, open-loop control, orthogonal coils, pan-tilt actuator, permanent magnet, Permanent magnet motors, Permanent magnets, position control, Scanning probe microscopy, second order system, spherical pointing motor, velocity control, Velocity measurement, velocity measurements

A miniature pan-tilt actuator, the spherical pointing motor (SPM) has been built. The SPM is an absolute positioning device, designed to orient a small camera sensor in two degrees-of-rotational-freedom. It is 4 cm×5 cm×6 cm and weighs 160 g. The operating principle of the SPM is to orient a permanent magnet to the magnetic field induced by three orthogonal coils by applying the appropriate ratio of currents to the coils. The open-loop control and design of the SPM are described. Physical characteristics and velocity measurements of the prototype are reported. The SPM is modeled with a simple second order system. Without control, it oscillates substantially when a single impulse is applied. By applying a second impulse without feedback, the oscillation can be reduced by as much as a factor of ten