Calibrating stepper motor by driving fractional ranges
AssigneeTrane International Inc.
InventorJoel C. VanderZee
Life of this patent
Estimating the term…
Abstract
A stepper motor driving a driven member is calibrated by periodically driving the member from its current operational position to an end stop of the driven member's total travel range; however, the driven member approaches the end stop in a series of ever-shorter travel segments. The first travel segment is less than ⅓ the total travel range to compensate for a possible sudden speed reversal, which can be accidentally triggered by the driven member reaching and “bouncing off” the end stop. Limiting the commanded first travel segment to less than ⅓ the total travel range prevents the driven member from reaching an opposite travel limit should the driven member suddenly reverse direction at three times the normal forward speed, wherein such triple speed is characteristic of reverse-speed situations.
Claims27
A method for calibrating a stepper motor that drives a driven member over a travel range having a travel limit, wherein the stepper motor can move the driven member to an operational point within the travel range, the method comprising:
- commanding the stepper motor to move the driven member over a travel distance from the operational point to the travel limit;
- and
- as the stepper motor moves the driven member from the operational point to the travel limit, commanding the stepper motor to periodically slow down, thereby creating a plurality of periods of relatively fast movement each separated by a period of slower movement, wherein the plurality of periods of relatively fast movement become shorter in distance as the driven member approaches the travel limit.
A method for calibrating a stepper motor that drives a driven member over a travel range having a travel limit, wherein the stepper motor can move the driven member to an operational point within the travel range, the method comprising:
- commanding the stepper motor to move the driven member over a travel distance from the operational point to the travel limit;
- and
- as the stepper motor moves the driven member from the operational point to the travel limit, commanding the stepper motor to periodically stop the driven member, thereby creating a plurality of periods of movement each separated by a pause, wherein the plurality of periods of movement become shorter in distance as the driven member approaches the travel limit.
A method for calibrating a stepper motor that drives a driven member over a travel range having a travel limit, wherein the stepper motor can move the driven member to an operational point within the travel range, the method comprising:
- commanding the stepper motor to move the driven member over a travel distance from the operational point to the travel limit and doing so through a plurality of periods of continuous movement, wherein the plurality of periods of continuous movement become shorter as the driven member approaches the travel limit;
- commanding the stepper motor to stop the driven member between the plurality of periods of continuous movement;
- and
- defining a reference point upon the driven member having reached the travel limit following the plurality of periods of continuous movement.
A system for calibrating a stepper motor, the system comprising:
- a driven member;
- a stepper motor that drives the driven member over a travel range having a travel limit, wherein the stepper motor can move the driven member to an operational point within the travel range;
- a controller operatively connected to and commanding the stepper motor to move the driven member over a travel distance from the operational point to the travel limit, wherein as the stepper motor moves the driven member from the operational point to the travel limit, the controller commands the stepper motor to periodically slow down or stop, thereby creating a plurality of periods of relatively fast movement each separated by a period of slower movement, wherein the plurality of periods of relatively fast movement become shorter in distance as the driven member approaches the travel limit.
A method of calibrating a stepper motor wherein the motor has a characteristic number of positions before a motor position cycle is repeated and wherein the motor moves a device over a known range of steps, the method comprising the steps of:
- initializing a calibration interval to be greater than the known range of steps;
- setting a next step value equal to ((1/number of positions)*calibration interval);
- driving the motor a number of steps equal to the next step value;
- determining if the calibration interval is less than a stop value;
- if yes, commencing a stopping sequence;
- or
- if no, modifying the calibration interval to equal (((number of positions−1)/number of positions)*calibration interval), and returning to the setting step.
A system for calibrating a stepper motor, the system comprising:
- a stepper motor wherein the motor has a characteristic number of positions before a motor position cycle is repeated and wherein the motor moves a device over a known range of steps;
- and
- a controller operatively connected to and commanding the stepper motor, the controller initializing a calibration interval to be greater than the known range of steps;
- setting a next step value equal to ((1/number of positions)*calibration interval);
- driving the motor a number of steps equal to the next step value;
- determining if the calibration interval is less than a stop value;
- if yes, commencing a stopping sequence;
- or if no, modifying the calibration interval to equal (((number of positions−1)/number of positions)*calibration interval), and returning to the setting step.
Dependencies are inferred from the claim text.