JPH04172506A - Position control method - Google Patents

Abstract

PURPOSE:To improve a working speed by dividing an amount of movement in unit time, by redistributing amounts of divided movement evenly selected frames of acceleration time, further by totalizing redistributed pieces of the amount of movement for each unit of time to calculate a speed command. CONSTITUTION:Assume an amount of movement of a control object to be 400 and its target speed to be 50 per unit of time, respectively, to divide the amount of move ment 400 per unit of time. The amount of movement 400 is divided into 8 unit time frames A-H. Next, acceleration time is specified for each unit time frame. In this case, the amount of time is redistributed by 10 each into continuous 5 unit time (acceler ation time) frames A-E. Next, an amount of movement 50 for unit time frame B is also evenly divided and redistributed into nit time frames B-F by 10 each. Likewise, an amount of movement 50 for each of unit time frames C-F is sequentially redistribut ed. Redistribution of an amount of movement for frame E is done by newly adding unit frame I whose initial distribution of an amount of movement is zero and by doing the distribution for frames E-I. Redistribution of amount of movement for frames F-H is also done by sequentially adding new unit time frames J-L. When all the redistributions are terminated, all amounts of movements are totalized for each of frames A-L.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a servo control device, and particularly to a position control method in a servo control device that controls the position of a controlled object such as an NC device or an automatic drafting machine.

[Conventional technology]

For technology to control the position of a controlled object, see Japanese Patent Application Laid-Open No.
There is an example described in Japanese Patent No. 129309. With this technology, when moving a stationary controlled object, the controlled object is first accelerated to a target speed, then moved at the target speed, and then decelerated.
Stop, but accelerate.

When decelerating, the acceleration is changed according to the target speed, which is reached in a fixed period of time.

FIG. 3 shows the concept of calculating the speed command, and shows the amount of movement of the controlled object 400. The case where the target speed is 50 per unit time and the acceleration time is 5 unit time is shown. Note that the unit time here is not necessarily a normal unit time such as 1 minute or 1 second, but may be a sampling time used for speed control. Eight units of time are obtained by dividing the moving amount 400 by the target speed 50. The amount of movement for each of these 8 units of time is 50
, are arranged in order as A-H.

When calculating the command speed for each unit time, the unit time A
Before , the unit time of the movement amount O is set to 4 unit times (0,,02,
O,,04), and after the unit time H, add the unit time of d81t+jto for 4 unit times (0,,O,,○,,O,'), respectively. Assuming that the commanded speed for the first unit time is V□9, then V 21 v, t... in order, these commanded speeds are calculated as follows.

V, = (O□+02+03+04+A) ÷5= (
4XO+50) ÷5=10 v2=(02+O,+O,+A+B) ÷5= (3X
O+50X2)÷5=20 V3= (03+O,+A+B+C)÷5= (2XO
+50
0 x 4) ÷ 5 = 40 V, = (A + B + C + D + E) ÷ 5 = (50 x 5
) ÷ 5 = 50 If you calculate by sequentially shifting unit time in this way, the third
A speed command for each unit time as shown in the figure is calculated. That is, a speed command for movement is calculated in which the acceleration time is 5 unit times, the speed after acceleration is 50, and the amount of movement is 400.

[Problem to be solved by the invention]

In the above conventional technology, the acceleration/deceleration time when moving the controlled object is constant, and the averaging time (the one that measures the target speed to obtain the amount of speed change per unit time) while the controlled object is moving. It is not possible to change the acceleration by changing the acceleration/deceleration time). In the above calculation example, for example, v
If we change the divisor 5 to 6 when calculating 4, and change the divisor 5 to 7 when calculating ■, then V4=33.3. V
.

= 35.7, the acceleration is smaller, but the unit time is 0
1. The amount of movement of A decreases, and the total amount of movement between unit times 02 to 08 does not reach 400, resulting in an insufficient amount of movement, which does not result in proper movement. Further, since the acceleration/deceleration time is constant, if the target speed differs, the acceleration will change, and uniform acceleration control cannot be performed.

When drawing nine curves such as circular arcs with a drafting machine, the curve is formed by connecting straight lines of minute length in a broken line, but in this case, even if the length of each straight line is short and the time to actually draw the line is short, Each straight line consumes a fixed amount of acceleration time, so it takes longer than necessary.

Furthermore, in the case of a machine tool, if you try to cut at high speed, the acceleration will increase because it accelerates at a high speed in a certain period of time, and the force applied to the machine will increase, which may cause strain.

An object of the present invention is to set the acceleration of movement of a controlled object according to the type of work in one work process.

[Means to solve the problem]

The above problem consists of a procedure for dividing and allocating the movement amount of the controlled object into the movement amount for each continuous unit time, a procedure for instructing the averaging time α for the continuous unit time, and a procedure for allocating the movement amount to each unit time. A procedure for uniformly redistributing the amount of movement that has been made into α continuous time units starting from the unit time, and a procedure for summing up the redistributed amount of movement for each unit time to obtain the speed for that unit time. This is achieved by having the following.

[Effect]

When the target movement amount and target speed (the movement speed after the end of acceleration) of the controlled object are given by the instruction unit, the target movement amount is divided by the target speed, and the required unit time (or sampling time) is calculated. Unit time frames equal to the number of calculated unit times are arranged in order, and the target movement amount is divided into movement amounts for each unit time and distributed to the unit time frames. An averaging time (acceleration time) α is specified for each unit time frame, and the amount of movement allocated to the unit time frame is continuous α starting from the unit time frame.
redistributed evenly into unit time frames. The amount of movement allocated to a unit time frame is sequentially redistributed in the same way, but there are places near the end of the unit time frame where there are no consecutive α unit time frames with the unit time frame at the beginning. come.

In this case, add a new unit time frame to which the movement amount is not allocated to the end of the column of time frames that have already been set,
Reallocate the amount of movement.

When the redistribution of the movement amount originally allocated to the unit time frame is completed for all unit time frames, the reallocated movement amount is aggregated for each unit time frame and converted into a speed command for the unit time frame. .

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

The amount of movement of the controlled object is 400, and the target speed is 5 per unit time.
An explanation will be given by taking a movement where the value is 0 as an example.

First, as shown in FIG. 1(A), the movement amount 400 is divided into movement amounts for each unit time. Since the amount of movement per unit time is equal to the target speed 50, the amount of movement 400 is divided into eight unit time frames A to H each having a movement amount of 50.

Next, as shown in FIG. 1(b), the acceleration time for each unit time frame is specified. Here, assuming that the acceleration time and 5 unit times are the same for all time frames, the movement amount 50 of the unit time frame A is evenly divided into 5 unit times of acceleration time, and the unit time frame A is the first unit time. 5 unit time (acceleration time) frames A and B.

1o each will be redistributed to C, D, and E. This acceleration time is
For example, the settings are set in advance for each type of work, such as drawing a straight line or two curves on a drafting machine, feeding the blade during machining, or moving the blade during machining without cutting, and are stored in the memory of the control device. Called according to the procedure.

Next, as shown in FIG. 1(c), the movement amount 50 of unit time frame B is similarly divided into five unit times of acceleration time, and unit time frames B, C, D, and E.

10 will be redistributed to F.

Similarly, as shown in FIG. 1(d), the movement amount 50 of each unit time frame (C-F) is sequentially redistributed. The movement amount redistribution for unit time frame E is based on the set unit time frame A.
-H does not have the 5 unit time to be allocated, so add a new unit time frame work whose initial movement amount allocation is 0,
Unit time frame E.

This is done for F, G, H, and I. Unit time frame F.

Similarly, the movement amount redistribution of G and H is performed using a new unit time frame J,
The redistribution is performed by sequentially adding L to , and when the redistribution of the movement amount of the unit time frame with the initial movement amount allocation is completed, the redistribution ends.

When the redistribution is completed, as shown in FIG. 1(e), the redistributed movement amount is totaled for each unit time frame A-L. Since the aggregated movement amount is the movement amount per unit time, it is the speed of the corresponding unit time frame. As can be seen from the figure, this speed is accelerated to a one-rod speed of 50 in 5 unit times of the m time frame A-E, and after maintaining the target speed of 50, it is decelerated and stopped again over 5 unit times. . Further, the total amount of movement in the unit time frames A-L is 400, and the initially specified movement has been realized.

In the above embodiment, the averaging time (acceleration time) is
Since the five unit times are the same as in the conventional example shown in the figure, the speed pattern is the same as in FIG. 3. However, in this embodiment, for example, when redistributing the movement amount per unit time frame, the averaging time (acceleration time) is set to 6, 50 is set to the unit time frame, and E.

The acceleration between unit time frames C, D, D, and E may be changed by uniformly distributing it to F, G, H, and I.

Even if this is done, the amount of movement that is reallocated to the entire unit time frame remains the same, and no inconvenience will occur.

Furthermore, if the averaging time used as a divisor at the time of reallocation is set to 6 instead of 5 for the entire unit time frame, the acceleration can be reduced.

Furthermore, for example, if the movement amount is 1200 and the target speed is 100, and the movement is performed with the same acceleration as in the embodiment of FIG. .

〔Effect of the invention〕

According to the present invention, when calculating a speed command, the amount of movement is divided into units of time, and then the amount of movement allocated to each unit of time is selected for each unit time frame or for each acceleration or deceleration. The reallocated travel amount is aggregated for each unit time frame and the speed command is calculated, making it possible to change the acceleration within one work process, making it possible to This has the effect of increasing the work speed by accelerating accordingly and preventing excessive stress from being applied to the mechanical equipment.

[Brief explanation of drawings]

FIG. 1 is a procedural diagram showing the calculation procedure of the present invention, FIG. 2 is an explanatory diagram showing an example of calculating a speed command by the method according to the present invention, and FIG. 3 is an explanatory diagram showing an example of calculating a conventional speed command. It is.

Claims (1)

[Claims] 1. In a method for controlling the position of a controlled object, the amount by which the controlled object moves per unit time after acceleration is completed is determined, the amount of movement of the controlled object is divided into continuous moving amounts for each unit time, and Indicate an averaging time α for the time, uniformly redistribute the movement amount allocated to each unit time to α consecutive unit times with the unit time at the beginning, and calculate the redistributed movement amount. A position control method characterized in that the speed is calculated for each unit time to obtain the speed for the unit time.