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# Simple Method to Handle Asymmetrical Profiles of Stepper Motors

IP.com Disclosure Number: IPCOM000034395D
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 47K

IBM

## Related People

Hoang, CM: AUTHOR

## Abstract

Disclosed is a software method to handle an asymmetrical velocity profile for stepper motors. Unlike symmetrical velocity profiles, asymmetrical velocity profiles are more difficult to handle, especially in short moves where the control software must decelerate the motor while the motor is in acceleration mode. The method described below provides a simple way to handle any asymmetrical velocity profiles. Because of the nature of the profiles, the control software needs two velocity profile tables. One is for acceleration and the other is for deceleration. As illustrated in the tables, each entry of the acceleration table contains an acceleration step time (AST) and its associated deceleration step (DS).

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Simple Method to Handle Asymmetrical Profiles of Stepper Motors

Disclosed is a software method to handle an asymmetrical velocity profile for stepper motors. Unlike symmetrical velocity profiles, asymmetrical velocity profiles are more difficult to handle, especially in short moves where the control software must decelerate the motor while the motor is in acceleration mode. The method described below provides a simple way to handle any asymmetrical velocity profiles. Because of the nature of the profiles, the control software needs two velocity profile tables. One is for acceleration and the other is for deceleration. As illustrated in the tables, each entry of the acceleration table contains an acceleration step time (AST) and its associated deceleration step (DS). The deceleration step (DS) is the number of steps required to decelerate the motor from the speed associated with the acceleration pointer AP. For example, a move of 8 steps requires 5 steps to accelerate and 3 steps to decelerate. At entry #5 of the acceleration table (AP=5), the deceleration step (DS(5)) should contain the value of 3. The deceleration table contains only the deceleration step times (DST). The last entry of this table contains the stabilization delay time.

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Before starting the move, the control software stores the total move steps K into the step counter SC and sets the profile table pointer PP to the first entry of the acceleration table (PP=0). The control software t...