A force feedback interface device that provides force feedback to a
joystick handle manipulated by a user. A force feedback device inputs
control signals to a computer and outputs forces to a user of the force
feedback device. The device includes a housing gripped by the user of the
force feedback device and a joystick handle manipulable in at least two
rotary degrees of freedom by the user, such as a gamepad. Sensors detect
a position of the joystick handle and two direct drive actuators each
provide torque in a rotary degree of freedom. Each of the actuators is a
brushless, single phase actuator having a grounded excitation coil and a
moving magnetic material. The joystick is mechanically constrained to not
move past either of two limits where the torque output by the actuator in
an unenergized state changes direction. The joystick handle can be
oriented such that a center position is substantially at a local minimum
reluctance position of the actuator, where the joystick is mechanically
constrained to not move substantially past either local maximum
reluctance position adjacent to the local minimum reluctance position.
The local minimum reluctance position can in some embodiments provide a
centering spring force on the joystick handle.