Abstract: A drive mechanism having a bi-stable motor driving an actuator 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 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 may be driven into a stop, and the coil resistance may be calculated by sensing current associated with the calibration voltage. Inductance 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 to maintain the desired rate.

Abstract: A drive mechanism configured to drive a thermally isolated actuator between two positions. The drive mechanism includes a rotary actuated motor configured to rotatably drive a motor member, and a drive member coupled to the motor member and having a drive arm configured to responsively move from a first position to a second position upon rotation of the motor member. An actuator is responsive to movement of the drive arm moved from the first position to the second position. A drive circuit is configured to generate a pulse width modulated (PWM) drive signal configured to controllably drive the motor, the PWM drive signal having a first duty cycle configured to advance the drive arm from the first position, and having a second duty cycle different than the first duty cycle as the drive arm approaches the second position. The drive signal may be removed before the drive arm engages a hard stop.

Abstract: A drive mechanism configured to drive a thermally isolated actuator between two positions. The drive mechanism includes a rotary actuated motor configured to rotatably drive a motor member, and a drive member coupled to the motor member and having a drive arm configured to responsively move from a first position to a second position upon rotation of the motor member. An actuator is responsive to movement of the drive arm moved from the first position to the second position. A drive circuit is configured to generate a pulse width modulated (PWM) drive signal configured to controllably drive the motor, the PWM drive signal having a first duty cycle configured to advance the drive arm from the first position, and having a second duty cycle different than the first duty cycle as the drive arm approaches the second position. The drive signal may be removed before the drive arm engages a hard stop.

Abstract: A drive mechanism having a bi-stable motor driving an actuator 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 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 may be driven into a stop, and the coil resistance may be calculated by sensing current associated with the calibration voltage. Inductance 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 to maintain the desired rate.