Methods of compensating for play and for initializing a position encoder in an actuation system (2) including an actuated system (8) comprising an elastic element, and an actuator (4) with a stepper motor (12) having at least one electrical phase.

Provided is a sensing system (1) in which a desired trajectory determining section (32) determines a first desired trajectory th(t) (where t<t1) whose first derivative is continuous, a second desired trajectory th(t) (where t2t<t3) whose first derivative is continuous, a third desired trajectory th(t) (where t1t<t2) configured with a common tangent line to the first and second desired trajectories, and a fourth desired trajectory th(t) (where t35t<t4) configured with a common tangent line to the second desired trajectory in the current-time cycle and a first desired trajectory in a next-time cycle. A drive mechanism controlling section (33) controls an operation of the drive mechanism so as to track the desired trajectories.

A calibration method for compensating a home position of a 3D printer is disclosed. According to a movement position of a movable mechanism of the 3D printer, a control voltage is provided to a microcontroller. The calibration method includes steps as follows. The movable mechanism moves in a home direction. It is to determine whether the microcontroller receives a first logic level signal which is transited according to the corresponding control voltage. If yes, the movable mechanism moves in a direction opposite to the home direction. It is to determine whether the microcontroller receives a second logic level signal which is transited according to the corresponding control voltage. If yes, the movable mechanism moves a compensation distance corresponding to a step compensation amount in the home direction. Therefore, the calibration method is provided to reduce circuit costs, simplify designs of control circuits, and accurately calibrate the home position.

A calibration method for compensating a home position of a 3D printer is disclosed. According to a movement position of a movable mechanism of the 3D printer, a control voltage is provided to a microcontroller. The calibration method includes steps as follows. The movable mechanism moves in a home direction. It is to determine whether the microcontroller receives a first logic level signal which is transited according to the corresponding control voltage. If yes, the movable mechanism moves in a direction opposite to the home direction. It is to determine whether the microcontroller receives a second logic level signal which is transited according to the corresponding control voltage. If yes, the movable mechanism moves a compensation distance corresponding to a step compensation amount in the home direction. Therefore, the calibration method is provided to reduce circuit costs, simplify designs of control circuits, and accurately calibrate the home position.

A driving device for a stepping motor includes a motor driving circuit configured to generate a current waveform representing an electrical angle in synchronization with a mechanical angle of the stepping motor, and excite the stepping motor using the current waveform; a memory configured to store a value of the electrical angle; and a controller configured to: when a power supply to the stepping motor and the motor driving circuit is stopped, store a first value of the electrical angle held by the motor driving circuit in the memory; and when the power supply is resumed, replace a value of the electrical angle of the motor driving circuit with the first value while suppressing a rotational operation of the stepping motor.

A first differential amplifier output drives a first winding of a stepper motor and a second differential amplifier output drives a second winding of the stepper motor. Inputs of the first and second differential amplifiers receive input drive signals generated by either a digital to analog converter or a pulse width modulator, where the input drive signals are phase offset sinusoids. Current flowing through a stepper motor winding is sensed to generate a current sense signal. A stall sensing circuit processes the current sense signal to determine whether the stepper motor has stalled by: taking a first derivative of the current sense signal to generate a first derivative signal; taking a second derivative of the current sense signal to generate a second derivative signal; and processing one or more of the current sense signal, the first derivative signal and the second derivative signal to detect a stepper motor stall condition.

A first differential amplifier output drives a first winding of a stepper motor and a second differential amplifier output drives a second winding of the stepper motor. Inputs of the first and second differential amplifiers receive input drive signals generated by either a digital to analog converter or a pulse width modulator, where the input drive signals are phase offset sinusoids. Current flowing through a stepper motor winding is sensed to generate a current sense signal. A stall sensing circuit processes the current sense signal to determine whether the stepper motor has stalled by: taking a first derivative of the current sense signal to generate a first derivative signal; taking a second derivative of the current sense signal to generate a second derivative signal; and processing one or more of the current sense signal, the first derivative signal and the second derivative signal to detect a stepper motor stall condition.

A control device for a stepping motor capable of suppressing a level of sound generated in association with driving of the motor is provided. The control device for a stepping motor is configured to, from when the hold period is started (t10) until the hold period ends (t12), gradually increase an absolute value of the excitation current in the A phase such that the amount of change in the excitation current per unit time is smaller than or equal to a first predetermined value. From when the hold period is started (t10) until a predetermined time elapses (t11), an absolute value of the excitation current in the B phase is gradually increased such that the amount of change in the excitation current per unit time is smaller than or equal to the first predetermined value. By the time the hold period ends (t12) after the predetermined time has elapsed (t11), the excitation current in the B phase is caused to reach zero. When the hold period ends (t12), one-phase excitation operation of the stepping motor is started such that the excitation current flows in the one phase first with the same polarity as at the end of the hold period.

A control device for a stepping motor capable of suppressing a level of sound generated in association with driving of the motor is provided. The control device for a stepping motor is configured to, from when the hold period is started (t10) until the hold period ends (t12), gradually increase an absolute value of the excitation current in the A phase such that the amount of change in the excitation current per unit time is smaller than or equal to a first predetermined value. From when the hold period is started (t10) until a predetermined time elapses (t11), an absolute value of the excitation current in the B phase is gradually increased such that the amount of change in the excitation current per unit time is smaller than or equal to the first predetermined value. By the time the hold period ends (t12) after the predetermined time has elapsed (t11), the excitation current in the B phase is caused to reach zero. When the hold period ends (t12), one-phase excitation operation of the stepping motor is started such that the excitation current flows in the one phase first with the same polarity as at the end of the hold period.

A motor controller capable of more reliably starting a stepping motor even if a predetermined drive power is supplied to the stepping motor, and to a control method for the stepping motor is provided. The motor controller driving a stepping motor detects that the stepping motor is in a step-out state after a start operation of the stepping motor is performed. If predetermined determination conditions are satisfied, when it is detected that the stepping motor is in a step-out state, it is determined that a restart operation of the stepping motor is performed, and the stepping motor is restarted.