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

Claim 3

A method according to claim 1, wherein precomputation is preformed by the microprocessor and the precomputed values are stored in memory after each change of at least one parameter which characterizes the shape of the curve velocity as a function of time and prior to starting of the motor.

Claim 4

A method according to claim 1, wherein the microprocessor computes each speed increase ΔV n with respect to the preceding speed V n on the basis of the formula ##EQU7## where k is a fixed coefficient which determines the fraction of the acceleration time represented by Δt and said acceleration curve is of exponential shape.

Claim 5

A method according to claim 3, wherein the period Δt corresponds to a fraction chosen between 1/50 and 1/500 of the acceleration time.

Claim 6

A mcthod according to claim 4, wherein the number of periods Δt in the acceleration time is chosen so as to ensure the precomputation can be performed by the microprocessor in a time interval of the order of 10 ms.

Claim 7

A method according to claim 1 for controlling acceleration and then deceleration of a motor, wherein, during the decleration period, the precomputed values (V n-1 +ΔV n ) stored in memory are read in the reverse order with respect to the reading operation performed during the acceleration period.

Claim 8

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 ΔV in a period Δt, 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 Δt, said first timer means being modified by said computation means at the end of each period Δt, 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.

Claim 9

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 ΔV in a period Δt, 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 Δt, said first timer means being modified by said computation means at the end of each period Δt, 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.

Claim 10

A generator according to claim 7, wherein said computation means further includes means for performing a further computation of the values V prior to starting of the motor if at least one of the parameters of the curve velocity as a function of time has changed.

Claim 11

A generator according to claim 8, wherein the series of values which can be assumed by the pulse frequency V is such that the difference in frequency ΔV n between two consecutive frequency values decreases during the acceleration stage and increases during the deceleration stage.

Claim 12

A generator according to claim 9, wherein the series of values which can be assumed by the pulse frequency V is such that the difference ΔV n between two consecutive frequency values is proportional to the difference between a desired maximum frequency V m and a lowest frequency V o of said consecutive frequencies.

Claim 13

A generator according to claim 10, wherein at least the parameters comprising the total number N of steps to be performed, the starting speed V o , the maximum speed V m and the time-duration of speed increase are determined by the user and introduced into the computing means.

Claim 14

A generator according to claim 11, wherein each change in pulse frequency V takes place only in a whole number of periods of said signal.