JPS6262365B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the speed of a servo motor.

Conventionally, most servo motor speed controls are controlled at the same speed regardless of the distance traveled, and even when speed control is performed according to the distance traveled, only the maximum speed is changed, etc. It was not a control method that moved at exactly the same time. Therefore, if the moving distance changes depending on the size of the object, there is a drawback that the cycle time of the entire device using the servo motor changes.

In order to eliminate the above-mentioned drawbacks, the present invention uses a speed profile obtained by similarly deforming a basic speed profile in which the motor speed is expressed as a function of the distance to the target value with respect to the reference movement distance according to the movement distance. Its purpose is to travel any distance in the same amount of time.

In order to achieve the above object, the present invention includes a movement amount storage unit that stores the amount of movement of the motor, a reference movement amount storage unit that stores a reference amount of movement, and a ratio between the amount of movement of the motor and the reference amount of movement. a basic speed profile storage section that stores a basic speed profile; a multiplier that calculates a speed profile to be actually used from the ratio of the movement amount and the basic speed profile; and a multiplier that calculates the speed profile to be actually used. It is composed of a speed profile storage section that stores a profile, and a speed profile reading section that reads out the speed profile according to the distance to the current target value.

The present invention will be described in detail below with reference to the drawings.

Figure 1 is a diagram showing the relationship between the basic speed profile and the speed profile according to the amount of movement.Basic speed profile 1 is set in advance in consideration of the controllability of the motor, corresponding to the standard amount of movement _Xs . ing.

If the basic speed profile 1 in _the case _{of the} movement _amount・F( _Xs / _XL・x)...
It is expressed as

The travel time T _s for the reference travel distance X _s is expressed by the formula T _s =∫ ^xs ₀ 1/F(X)dx . On the other hand, the travel time T _L for the travel distance X _L is calculated from the formula _{Then ,} ^if we _{set X s /} ,
From the formula, P _L =X _s ... Therefore, from the formula and the formula, T _L =∫ ^xs ₀ 1/F(P) dp ... Since the formula and the formula are synonymous, they move in the same time.

FIG. 2 is a block diagram showing the configuration of the control section. The movement amount storage unit 3 first receives the movement amount of the motor, and the division unit 5 receives the reference movement amount stored in the reference movement amount storage unit 4 and the movement amount storage unit 3.
Calculate the ratio with the actual amount of movement stored in . The basic speed profile storage unit 6 stores a basic speed profile in which the motor speed is expressed as a function of the distance to the target value with respect to the reference moving distance. B, speed B) (distance C, speed C)... The multiplier 7 multiplies each distance and each speed of the profile by the ratio of the moving amounts and writes the result into the speed profile storage section 8. For example, let the ratio of the amount of movement be α
Then, the data written to the speed profile storage section 8 is (distance A x α, speed A x α) (distance B x α, speed B x α,) (distance C x α, speed C x
α)...

On the other hand, the amount of movement of the motor is also input to the amount of movement counter 9. The movement amount counter 9 decrements the counter value in response to pulses output from the position detector 13 as the motor rotates. That is, the value of the movement amount counter 9 indicates the remaining distance to the target value. The speed profile reading unit 1 reads out the speed setting value corresponding to the value of the movement amount counter 9 from the speed profile storage unit.
0, this output becomes the speed command value. The servo control unit 11 compares the speed command value and the output from the motor speed detector 14, and applies current to the motor 12 so that the motor speed becomes the command value.

As explained above, according to the present invention, it is possible to travel different travel distances in the same time,
Simultaneous control of the two axes not only allows the target values to be reached at the same time, but also has the effect of keeping the cycle time of the device constant.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between a basic speed profile and a speed profile according to the amount of movement, and FIG. 2 is a block diagram showing the configuration of a control section according to the present invention. 1... Basic speed profile, 2... Similar speed profile, 3... Movement amount storage section, 4... Reference movement amount storage section, 5... Division section, 6... Basic speed profile storage section, 7 ...Multiplication unit, 8...Speed profile storage unit, 9...Movement amount counter, 10
...Speed profile reading section, 11... Servo control section, 12... Motor, 13... Position detector, 14... Speed detector.

Claims (1)

[Claims] 1 The servo motor operates according to the speed profile obtained by multiplying the basic speed profile, which expresses the motor speed as a function of the distance to the target value for the reference movement distance, by the ratio of the reference movement distance and the actual movement distance. A method for controlling a servo motor, which is characterized by moving an arbitrary distance in the same amount of time by driving a servo motor.