US 4,684,865 A · Method and device for controlling the acceleration of an electric stepping motor

Abstract

In order to attain the maximum permissible speed of a stepping motor and to achieve a substantial reduction in the time required to perform a predetermined number of steps, acceleration between the starting speed V.sub.o and the maximum speed V.sub.m takes place in the form of incremental increases .DELTA.V.sub.n in the frequency of the signal for controlling the speed of the motor at time intervals .DELTA.t which are all equal. All the speeds V.sub.n-1 +.DELTA.V.sub.n are precomputed by a microprocessor and the precomputed values are stored in memory. These values are read at each instant t+.DELTA.t during the acceleration period and in the reverse order with respect to the deceleration period. The curve velocity V is a function of time t is of exponential form with a negative exponent.

Claims12

Dependent claims

A method for controlling the acceleration of an electric stepping motor between a starting speed V.sub.o and a maximum value V.sub.m in incremental increases .DELTA.V.sub.n of the motor control pulse frequency, wherein said method comprises the steps of:

dividing the acceleration time into a predetermined number of equal periods .DELTA.t each representing a fraction of said acceleration time;
computing beforehand by means of a microprocessor all the speed values (V.sub.n-1 +.DELTA.V.sub.n) corresponding to each period .DELTA.t, .DELTA.V.sub.n is smaller than the increase .DELTA.V.sub.n-1 of the immediately proceeding period .DELTA.t during at least the final portion of the acceleration phase;
storing in a RAM memory data representative of values which have thus been precomputed;
producing a signal having a period .DELTA.t which is applied to the microprocessor so that the precomputed values (V.sub.n-1 +.DELTA.V.sub.n) stored in memory should be read successively by said microprocessor at each interval .DELTA.t;
and
transmitting during each period said values (V.sub.n-1 +.DELTA.V.sub.n) in the form of a pulse frequency to the system for controlling the motor windings.

3 more elements

A programmable acceleration generator for controlling the speed of an electric stepping motor, said motor including a switching and amplifying means for producing angular motor movements in incremental steps, said generator comprising:

programmable microprocessor computation means for generating a pulse frequency V which serves to control said switching and amplifying means, and for periodically changing the pulse frequency V by a value .DELTA.V in a period .DELTA.t, wherein a series of values which can be assumed by the pulse frequency V is precomputed by said computation means, where V is a function of time;
random access memory (RAM) means for storing said precomputed values in a given order;
a first timer means for delivering the pulse frequency V to said switching and amplifying means;
a second timer for delivering a signal having a period .DELTA.t, said first timer means being modified by said computation means at the end of each period .DELTA.t, said series of values precomputed by said computation means being read from said RAM means in order during an acceleration stage and being read in a reverse order during a deceleration stage.

1 more element

Dependencies are inferred from the claim text.

Method and device for controlling the acceleration of an electric stepping motor

Life of this patent

Method and device for controlling the acceleration of an electric stepping motor

Life of this patent

Abstract

Claims12