| 摘要 |
A drive mechanism (16A, 16B) having a bi-stable motor (18) driving an actuator (22) with a high starting torque, and a slower, regulated velocity as the actuator moves through its range of travel. This advantageously maintains high torque margins at low velocity, and lowers the kinetic energy of the bi-stable actuator at end of travel by limiting the terminal velocity (Wm) and establishing a softer stop. A solenoid may be used in one embodiment. Actual bi-stable motor values are obtained immediately before the move to maintain accurate control of the motor, such as the resistance and inductance of the motor coil. For instance, the bi-stable motor (46) may be driven into a stop (50, 52), and the coil resistance(Rm) may be calculated by sensing current (Im) associated with the calibration voltage (Vd). Inductance (Lm) may be measured similarly by applying low level AC currents. Back-emf is sensed through the coil resistance, and an estimated motor rotation rate is sent to a feedback loop (68) to maintain the desired rate. |
