Performance of a superconducting large-angle magnetic suspension

Low-noise torque sources will be used to control and point large missions such as Space Station and its co-orbiting platforms. Conventional torquing actuators will have problems in terms of life and vibration. SatCon Technology Corporation has been developing the component technologies required for an advanced control moment gyro (CMG) type of actuator for large payloads. The key component of the CMG is a large-angle magnetic suspension (LAMS). The LAMS combines the functions of the gimbal structure, torque motors, and rotor bearings of a conventional CMG. The LAMS uses a single superconducting coil and an array of normal control coils to produce a specific output torque more than an order of magnitude greater than conventional devices. SatCon is currently testing a laboratory-scale superconducting LAMS. The LAMS system is based around an available superconducting solenoid and a multi-input, multi-output control system. The purpose of the experiment is to demonstrate the control laws for stabilizing and controlling the LAMS system. The controller is, of course, the key component of most magnetic suspension systems. This paper describes the design and fabrication of the superconducting LAMS and presents the results of the system testing. The innovative system features include and inductive large-angel rotation sensor and a continually-updated force/current excitation model built into the controller software