Synchronous control device

Details Synchronous control device Synchronous control device

1999-07-29

2001-04-10

Nappi, Robert E. (Department: 2837)

Electricity: motive power systems

Synchronous motor systems

C318S705000, C318S609000, C318S268000

Reexamination Certificate

active

06215270

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a synchronous control apparatus for driving a subsidiary shaft motor synchronously with a main shaft motor.
BACKGROUND ART
According to the conventional synchronous control technique, a command is synchronously provided to the main shaft motor control device and the subsidiary shaft motor control device, respectively. Alternatively, a command is provided to the subsidiary shaft motor control device synchronously with the present position of the main shaft motor. Further, the present applicant proposed a synchronous control apparatus in which the predictive control is applied to the synchronous control as disclosed in Japanese Patent Application No. 6-288994. In the synchronous control apparatus described above, predictive control is conducted on the subsidiary shaft by a future position command of the subsidiary shaft obtained by predicting a future position of the main shaft.
However, according to the conventional synchronous control technique, it is difficult to conduct synchronous control with high accuracy because the dynamic characteristic of the main shaft is different from that of the subsidiary shaft. The art disclosed in Japanese Patent Application No. 6-288994 is proposed in order to solve the above problem and to enhance the synchronous accuracy. However, the following problems may be encountered hen the above device is used. In this device, when the future main shaft position is predicted, not the main shaft position command of the future but the main shaft position command at the present moment is used. Therefore, when the main shaft position command is changed, control can not be changed in quick response, and the synchronous accuracy is deteriorated.
According to the conventional synchronous control technique, when input of the position command into the main shaft control device and the subsidiary shaft control device is delayed or when detection of the main shaft position is delayed, the synchronous accuracy is deteriorated in accordance with the delay.
The present invention has been accomplished to solve the above problems. It is an object of the present invention to provide a synchronous control apparatus capable of realizing synchronous control, the control accuracy of which is higher than that of the conventional apparatus. Further, synchronous accuracy of this synchronous control apparatus is not deteriorated even if input of the position command is delayed and also detection of the main shaft position is delayed.
SUMMARY OF THE INVENTION
In order to solve the above problems, there is provided a synchronous control apparatus by which a subsidiary shaft motor is driven synchronously with a main shaft motor, comprising: a command generating device into which an increment of the main shaft position command &Dgr;r
s
(i+M−1) in the sampling period is inputted and also an increment of the main shaft position &Dgr;y
s
(i−K) before K (K≧0) times of the samplings is inputted, and from which an increment of the main shaft position command &Dgr;r
s
(i) is outputted and also a plurality of increments of the subsidiary shaft future position &Dgr;r
s
(i+m), m=D+, D+2, . . . , D+M, which are for several times of future samplings are outputted; a main shaft device into which a signal of the main shaft position command increment &Dgr;r
s
(i−d) delayed by d (d≧0) times of samplings is inputted for controlling the drive of the main shaft motor, and from which an increment of the main shaft position &Dgr;y
s
(i) is outputted; and a subsidiary shaft device into which signals &Dgr;r
s
(i+m), m=1, 2, . . . , M of the plurality of subsidiary shaft future position command increment delayed by D (D≧2 0) times of samplings are inputted, and which controls the drive of the subsidiary shaft motor so that the subsidiary shaft position predicted by the dynamic characteristic model of the subsidiary shaft can be made to coincide with the future position command of the subsidiary shaft, wherein the command generating device includes: first memory means for storing the main shaft position command increments inputted into a plurality of time points from the past to the present; output means for outputting the main shaft position command increment &Dgr;r
s
(i) inputted before (M−1) times of samplings in the values stored in the first memory means; second memory means for storing the main shaft position increments inputted into a plurality of time points from the past to the present; a calculator for finding predicted values of a plurality of main shaft position increments for several times of future samplings by the dynamic characteristic model of the main shaft device including delay factor which is d times of samplings and also by the stored main shaft position command increments and the stored main shaft position increments; and a converter for finding a plurality of subsidiary shaft future position command increments by a plurality of predicted values of the main shaft position increments obtained by the calculator.
According to the present invention, there is also provided a synchronous control apparatus for driving a subsidiary motor synchronously with a main motor comprising: a fine adjustment device for inputting a signal into the subsidiary shaft motor control device as a fine adjustment signal for adjusting the asynchronization, the signal obtained by adding a signal, in which an increment of the main shaft position in the sampling period or the predicted value is multiplied by a multiplier K
1
, to a signal, in which the main shaft position command increment is multiplied by a multiplier K
2
,; and means for switching the value of the multiplier K
1
according to the positive or negative of the main shaft position increment.
According to the present invention, there is also provided a synchronous control apparatus by which a subsidiary shaft motor is driven synchronously with a main shaft motor, comprising: a command generating device including: a memory means into which an increment of the main shaft position command &Dgr;r
s
(i+M−1) in the sampling period is inputted and also an increment of the main shaft position &Dgr;y
s
(i−K) before K (K≧0) times of samplings is inputted; the memory means respectively storing the inputted main shaft position command increment and the main shaft position increment; an output means for outputting the main shaft position command increment &Dgr;r
s
(i) inputted before (M−1) times of samplings in- the values stored in the memory means; a calculator for finding predicted values of a plurality of main shaft position increments for several times of future samplings; and a converter for finding and outputting a plurality of subsidiary shaft future position command increments &Dgr;r
s
(i+m), m=D, D+1, D+2, . . . , D+M by a plurality of predicted values of the main shaft position increments obtained by the calculator; a main shaft device into which a signal &Dgr;r
s
(i−d) of the main shaft position command increment delayed with d (d≧0) times of samplings is inputted for controlling the drive of the main shaft motor, and from which an increment of the main shaft position &Dgr;y
s
(i) is outputted; a subsidiary shaft device into which signals &Dgr;r
z
(i+m), m=0, 1, . . . , M of the plurality of subsidiary shaft future position command increment delayed by D (D≧0) times of samplings are inputted, and which controls the drive of the subsidiary shaft motor so that the subsidiary shaft position predicted by the dynamic characteristic model of the subsidiary shaft can be made to coincide with the future position command of the subsidiary shaft; and a fine adjustment device for inputting a signal delayed by D (D≧0) times of samplings of a signal obtained by adding a signal, in which one of the increment of the main shaft position and the predicted value is multiplied, to a signal, in which the main shaft position command increment is multiplied, into the

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