JPS63221402A - Pitch error correcting method - Google Patents

Abstract

PURPOSE:To correct the pitch errors by securing a ring structure for a servo processor memory to write the pitch error correction information into this memory and then extracting successively said correction information in the moving direction of a machine to rewrite the end area of the ring structure. CONSTITUTION:A positioning device consists of a main processor 1, a memory 2, a servo processor 3 and a memory (pitch correction information memory) 4. The correction information is set opposite in 1:1 to the position on the machine stroke. When the address of the memory 4 is replaced in a shift on the machine stroke for compensation of the difference of memory capacity between both memories 1 and 3, the information 9 on the memory 2 is rewritten with width 6 of the memory 4 based on the pass through a certain point 7 (or 8) and transferred to an address 10 of the memory 4. In this case, the information 9 is actually sent to a physical memory address 11 owing to a ring structure of the memory 4. Thus the rewriting timing has the hysteresis characteristics. The memory width 6 to be rewritten is selected properly so that a pitch error can be corrected with no limit of capacity of the memory 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pitch error correction method for a positioning device using a ball screw.

[Conventional technology]

Conventionally, in this type of positioning device, the variation due to the pitch of the ball screw is measured in advance, the data is made to correspond one-to-one to the stroke position of the machine as pitch error correction data, and it is registered in the main processor memory in the order of the stroke position. Then, as the machine moves, the servo processor reads pitch error correction data corresponding to the stroke position from the servo processor memory and performs pitch error correction processing.

(Problems to be Solved by the Invention) In the conventional pitch error correction method described above, if the memory sizes of the main processor memory and the servo processor memory are the same and the servo processor memory is limited, it is not possible to set a large number of correction points. Furthermore, in submicron control, etc., in order to make the cumulative pitch error correction amount fall within the desired value, the correction interval must be shortened, resulting in a shortage of correction points or the need to increase memory capacity. It has the disadvantage that it cannot be used.

[Means for solving problems]

In the pitch error correction method of the present invention, the servo processor memory has a ring structure, and first, pitch error correction data is written from the main processor memory to the servo processor memory by the capacity of the servo processor memory corresponding to the initial position of the machine. After that, each time the machine moves a predetermined distance, the remaining pitch error correction data in the main processor memory is sequentially retrieved from the main processor memory in predetermined increments in the machine's moving direction, and the servo processor memory's logic for the machine's moving direction is read out. The upper area, in other words, since the servo processor memory has a ring structure, physically the area at the end of the ring is rewritten.

[Effect]

Therefore, it is possible to cover the difference in capacity between the main processor memory and the servo processor memory regarding the pitch error correction data, and to apparently increase the capacity of the pitch error correction data memory of the servo processor.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing only the main parts of a positioning device to which the pitch error correction method of the present invention is applied, FIG. 2 is a diagram showing a pitch error correction data extraction method of the servo processor 3, and FIG. 3 is a diagram showing the memory 2 4 and 5 are diagrams illustrating the relationship between the memory 4 and the mechanical stroke, FIGS. 4 and 5 are explanatory diagrams of the algorithm of the present invention, and FIG. 6 is a diagram illustrating an example of rewriting pitch error correction data in the memory 4.

As shown in FIG. 1, this positioning device includes a main processor 1, a memory 2 of the main processor 1, a servo processor 3, a memory (pitch error correction data memory) 4 of the servo processor 3, and other devices not shown. It is configured.

In the pitch error correction data memory 4, as shown in FIG. 2, the data is logically arranged in a circular pattern. Further, the pitch error correction data in the memory 4 are a-A and b-B, as shown in FIG.

There is a one-to-one correspondence with the position of the mechanical stroke L, such as c-C and d-D.

In order to compensate for the memory capacity difference between the pitch error correction data memory 2 of the main processor 1 and the pitch error correction data memory 4 of the servo processor 3, which cover the entire machine stroke in Fig. 4: @mechanical stroke - movement at E When the address of the pitch error correction data memory 4 is updated, the memory 4 is rewritten with a memory width of 6 on the condition that a certain point 7 (or 8) has been passed. The data to be rewritten is data 9 in memory 2 in FIG. 5, and is logically transferred to memory address 10 in memory 4. However, in reality, as shown in FIG. 2, the pitch error correction data memory 4 of the servo processor 3 is logically formed into a ring, so that the data is transferred to the physical memory address 11. Therefore, the timing of memory rewriting accompanying movement on the mechanical stroke 55 in FIG. 6 is 51 in FIG.
It has a hysteretic property as shown in . In other words, to explain with reference to FIG. 3, data d at address 4 of memory 4
The timing of rewriting e to e corresponds to the position of the machine stroke, and is executed when passing B from C to A, but after passing B and before reaching A, it is reversed and rewritten again. The property that rewriting is not executed even after passing through B is said to have hysteresis. For example, machine stroke [
If the pitch error correction data storage of the servo processor 3 is set to l), C, d, and e from the left at position 52, then when it moves in the child direction and passes position 53, memory rewriting is executed. The contents are f, c, d, and e. next,
When moving in one direction and passing through the position 52, the memory 4
The memory 4 becomes C, d, and e, and after passing through the A device 54, the memory 4 becomes Su, c, d, and a. In the case of FIG. 6, the rewritten memory width is 174 in the pitch error correction data memory 4 of the servo processor 3. Since there is a relationship that reducing the memory width will result in more frequent rewriting, system operation and the pitch error correction data memory of the servo processor 3 can be performed by selecting the memory width that is optimal for the overhead associated with the rewriting time. Pitch error correction processing can be performed without being limited by capacity.

(Effects of the Invention) As explained above, the present invention retrieves the pitch error correction data of the main processor in predetermined sizes in the moving direction of the machine with respect to the pitch error correction data of the servo processor memory, and Covers the memory capacity difference between the main processor and the servo processor by transferring it to the last area in the direction of movement.
This has the effect of apparently increasing the pitch error correction data memory of the servo processor.

[Brief explanation of drawings]

FIG. 1 is a diagram showing only the main parts of a positioning device to which the pitch error correction method of the present invention is applied, FIG. 2 is a diagram showing a pitch error correction data extraction method of the servo processor 3, and FIG. 3 is a diagram showing the memory 2 4 and 5 are diagrams illustrating the relationship between the memory 4 and the mechanical stroke, FIGS. 4 and 5 are explanatory diagrams of the algorithm of the present invention, and FIG. 6 is a diagram illustrating an example of rewriting pitch error correction data in the memory 4. ■... Main processor, 2... Memory of main processor l, 3...
Servo processor, 4... Memory of servo processor 3, 5... Logical ring of pitch error correction data of servo processor 3, 6... Rewriting memory width, 7.8 -aPA timing, 9. IO1+1 -... Rewrite memory, 51 ・
... State transition at handover timing, 52.53.54
... Position of machine stroke F, 55 -...
mechanical stroke.

Claims (1)

[Claims] In a positioning device that includes one or more servo processors that control a motor, a main processor that controls these servo processors, a servo processor memory attached to each of the servo processors and the main processor, and a main processor memory, variations due to the pitch of a ball screw can be detected. is measured in advance, the data is made to correspond one-to-one to the stroke position of the machine as pitch error correction data, and is registered in the main processor memory in the order of the stroke position, and then transferred to the servo processor memory,
In a pitch error correction method that performs pitch error correction processing by reading pitch error correction data corresponding to the relevant stroke position from a servo processor memory as the machine moves, the servo processor memory has a ring structure, and first, the initial position of the machine is Pitch error correction data is written from the main processor memory to the servo processor memory corresponding to the capacity of the servo processor memory, and thereafter, every time the machine moves a predetermined distance, the remaining pitch error correction data in the main processor memory is written to the predetermined value. The size is taken out from the main processor memory in the direction of movement of the machine, and the logical area of the servo processor memory in the direction of movement of the machine.In other words, since the servo processor memory has a ring structure, physically the ring A pitch error correction method characterized by rewriting the region at the end of the pitch error correction method.