JPS63146105A - Locus controller - Google Patents

Abstract

PURPOSE:To generate a locus having high accuracy by determining the next moving point on a locus by the output of a digital filter and a locus command value, calculating the coordinates of the moving point, and deriving each axis moving component of a sampling period. CONSTITUTION:A segment buffer memory 26 stores successively length DELTAL of a segment, coordinate components DELTAX, DELTAY of the segment, a moving speed F, and a control signal C consisting of the state quantity of start/end, etc., of a block and an acceleration/deceleration control command value, etc., as one unit of segment information. In this state, by using a path length and a speed command value from the segment buffer memory 26, a speed signal (fi) is generated, it is smoothed by using a digital filter 31, and thereafter, by using this speed signal (fi) a path interpolation is executed. In such a way, the exact locus command value of a smooth speed control is generated, and an exact locus control which does not depend on magnitude of a speed can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a trajectory control device that generates trajectory control signals in control devices for machine tools, robots, and the like.

[Prior Art] Conventionally, this type of trajectory control device includes, for example, Automatic Control Technology 26 (edited by Japan Automatic Control Association, 1978), pages 89-94.
There is a numerical control device described in , and a block diagram showing its configuration is shown in FIG.

In the figure, (1) is a command value input section, (2) is an interpolation calculation section, (3) is a smoothing processing section, and (4) is a servo drive section.

The command value input section (1) has a function of inputting and storing an operation command value from a push button on an operation panel, a paper recorder, or other input medium. The command value for one trajectory is called a block, and for example, when controlling the two axes of X and Y, this consists of information such as the amount of movement (Y, X).

In addition, in the case of arc movement, it consists of information such as the center coordinates (I, J) of the arc relative to the starting point of Pro 9, movement speed (F), trajectory type (straight line/circular arc), acceleration/deceleration control command value, etc. . The interpolation calculation unit (2) has a function of receiving command values in blocks from the command value input unit (1) and sequentially calculating coordinates on the trajectory.

FIG. 8 is a diagram showing an example of the configuration of the above-mentioned interpolation calculation section (2), and FIG. 9 is a diagram showing an example of calculation processing of circular interpolation. Each process of the interpolation calculation unit (2) is executed at a constant sampling period ΔT. The segment length calculation unit (10) takes the product of the command speed F and the sampling period ΔT, and calculates the amount of movement ΔL(-
Calculate F・ΔT). The coordinate calculation unit (11) calculates the coordinates (X, Y) of the previous interpolation point P (16).
Calculate the coordinates (X, Y) of the next interpolation point P, (17) on the axis track a distance 1-i i-t i- from Δt i- forward. Block end determination unit (12
) is the point P, (17) is the end PE of the block (18)
It is determined whether it is equal to or exceeds this, and if it is, the coordinates of PE are replaced with the coordinates of PI, and processing of a new block is started from the next sampling period. The movement amount axis component calculation unit (13) calculates each coordinate axis component ΔX 1 of the movement segment ΔL (15) during the current sampling period.
ΔY1 is determined by ΔXi ``Xl ''−Xi−1 ΔY, −Yi−Y, −1, respectively, and sent to the next smoothing processing unit (3).

The smoothing processing unit (3) receives the movement command for each coordinate axis (the amount of movement during T to the sampling period (ΔX 1ΔY1)) obtained by the interpolation calculation unit (2), and calculates each temporal change rate (acceleration). is processed so that it is below a certain value, and converted into a smooth speed command so that the servo drive unit (4) can follow it correctly and drive the machine smoothly.

FIG. 10 shows an example of the configuration of the smoothing processing section (3), but since the same processing is performed independently for each axis, the configuration related to the X-axis will be described here.

Here, the sampling period Δt of the smoothing processing section (3) is 1/1 of the sampling period ΔT of the interpolation calculation section (2).
It is set to 16. First, the division processing unit (20) sequentially divides the output ΔX1 of the interpolation calculation unit (2) into moving amounts ΔX1 corresponding to the sampling period Δt by multiplying it by 1/16. Next, this result is passed through a digital filter (21).
After smoothing it and converting it into a smooth speed command ΔP, it is output to the servo drive unit (4). The processing during this time is expressed as follows, for example.

However, j-0, 1, 2,... ΔP -0, D -0, T: Smoothing time constant ΔX1 above is updated every 16 cycles with the next new output of the interpolation calculation unit (2) be done. The above series of calculations is performed in exactly the same way for the Y axis, and ΔY1 is converted to ΔQj.

The servo drive unit (4) has a function of receiving an output command from the smoothing processing unit (3) and driving the rotation angle of each drive shaft servo motor to match the command value, and
Axis traces are generated by combining the movements of the moving mechanisms of each Y axis.

In the process of equation (1) above, D corresponds to the storage of the command value when converting the X-axis speed command value at each sampling time from ΔX to ΔP, so This appears as a delay in instructions.

Therefore, in the above example, if the axis trace here is generated using ΔP and ΔQ, an error corresponding to the command delay will occur between it and the original command trajectory, and furthermore, this error will cause a large speed difference. It will increase accordingly.

[Problems to be Solved by the Invention] As described above, conventional trajectory control devices are configured to perform smoothing processing after performing interpolation calculations on the trajectory, and for this reason, commands for each axis of the servo drive unit There was a delay in the value, and this delay caused a trajectory error. Since the magnitude of the delay 'corresponds to the magnitude of the speed, there is a problem in that the error becomes extremely large when driving at high speed.

This invention was made in order to solve the above-mentioned problems, and the object is to obtain a shaft trace control device that can generate high-precision shaft marks and perform high-speed and smooth speed control. .

[Means for Solving the Problems] A trajectory control device according to the present invention includes a path length calculation device that calculates the path length of a trajectory based on a given trajectory command value, and a path length calculation device that calculates the path length of a trajectory based on a given speed command value and the trajectory control device. Speed signal generation means for generating a moving speed signal using the output of the path length calculation means;
A digital filter that forms a speed signal waveform based on the output of the speed signal generating means, and a digital filter that calculates a moving component of the trajectory based on the formed speed signal and the trajectory command value, and calculates each drive of the moving component. and interpolation calculation means for sequentially calculating axial components.

[Operation] In the present invention, the interpolation calculation means determines the next moving point on the axis track based on the output of the digital filter and the trajectory command value, calculates the coordinates of the moving point, and determines each axis movement component of the sampling period. .

[Embodiment] FIG. 1 shows the configuration of an embodiment of the present invention. In the figure, the first interpolation calculation unit (2) selects movement command values (X, Y, I,
J) A function that receives information such as the type of axis trace (circle/straight line), divides and interpolates the command trajectory into straight line segments with the required accuracy, and writes the calculation results to the segment buffer memory (26) according to the available space. have. The segment buffer memory (26) stores the segment length ΔL) calculated by the first interpolation calculation unit (2), the coordinate components of the segment (ΔX, ΔY), and the movement speed output from the command input unit (1). (F) and a control signal (C) consisting of state quantities such as block start/end, acceleration/deceleration control command values, etc., are sequentially stored as one unit of segment information. The speed control processing section (27) has a constant minute sampling period Δ.
Segment information is sequentially read from the segment buffer memory (26) every t, and a movement command (Δ
P1. ΔQ1) and drive the servo! Send to section (4).

Figure 2 is a block diagram showing the hardware configuration of Figure 1.
00) is the main CPU, (102) is the main memory (ROM)
), (103) is the standard input/output IZF meme memory AM)
, (104) is NC data memory (RAM), (10
5) is a servo controller, (106) is a CRT, (1
07) is a keyboard, and (108) is a machine tool.

The command input section (1) in Fig. 1 includes a standard input/output I/F meme memory 103), an NC data memory (104),
It is composed of a CRT (106) and a keyboard (107), and the first interpolation calculation unit (2) is connected to the main memory (
The main CPU (100) performs calculation operations based on programs stored in the main CPU (102).

Further, the segment buffer memory (26) is configured by an NC data memory (104), the speed control processing unit (27) is configured by the main CPU (100), and the servo drive unit (4) is configured by the servo drive unit (4). It is configured by a controller (105).

Next, the speed control processing section (27), which is the core of the present invention in the above-described configuration, will be explained in detail. FIG. 3 is a block diagram showing the configuration of the speed control processing section (27), and FIG. 4 is a flow chart showing its operation.

The speed command generation unit (30) generates the speed command value F1 segment length Δ read from the segment buffer memory (26).
L and control information C are read (Sl), and using these data, the movement amount F·Δt for each sampling period Δt is determined, and this is output as the speed command value F (S2). Furthermore, each time the command value is output, the remaining distance of the segment is determined (S3), and the remaining distance is determined (S4). If it is determined that the moving distance exceeds the segment length ΔL (remaining distance
), until the block ends (S5), the first read control unit (31) is driven to read the next segment information.S6), rounding is performed so that the values of F are continuous. , generates a speed command that smoothly connects segments. This operation is repeated until the segment in which the block end flag included in the control information C is set, yielding a speed command F1 in the form of a stair-four as shown in FIG. 5(A). At this time, the sum total of FI for each sampling output is output so as to be equal to the sum total of the segment lengths ΔL of the locus of one block.

On the other hand, if the moving distance does not exceed the segment length ΔL, the speed command F is
1), a speed signal f1 formed as shown in FIG. 5(B) is obtained (S7). The speed signal f1 is added and integrated by the next integrator (32), and the moving distance from the segment start end is calculated (S8). The segment end determination unit (33) compares Ll and ΔL (S9).

If the segment end determination unit (33) determines that Ll is smaller than ΔL, take the segment length ΔL, calculate the ratio (-Ll/ΔL) (S10), and then calculate ΔP1 and ΔQ1 using the following formula. Find it (S11).

However, i-1, 2, 3,... Self... ΔX! ΔY −〇0 〇On the other hand, when it is determined that the moving distance Li exceeds the segment length ΔL, the second lead control section (34)
5 to read the next segment information to the segment end determination unit (33) and proportional interpolation calculation unit (35).
12), perform rounding so that the excess of the moving distance LI is absorbed in the next segment, and calculate the fractional value by an integrator (32).
) and the proportional interpolation calculation unit (35), and reset the initial conditions for each process. Then, the proportional interpolation calculation section (3
5) is each coordinate axis component (ΔX.

A movement command (ΔP, ΔQ,) is calculated using the output of the segment end determination unit (33) and the segment end determination unit (33) (S13).
. That is, as shown in FIG. 6, when L exceeds ΔL, the moving point moves from the current segment (40) to the next segment (41). In this case, point A (42), which has progressed on the next segment (41) by the amount of overlapping (L knee ΔL), is set as the next moving point, and from the previous moving point P (43) to point A (42). By setting the coordinate axis components of the displacement amounts to ΔP and ΔQ1, respectively, it is possible to form a movement command that smoothly connects the movement between segments.

Although the above embodiment describes the generation of a movement trajectory in two X-Y axes, it can of course be applied to cases in which there are three or more axes. A similar effect is exerted on the generation of shaft marks.

[Effects of the Invention] As described above, according to the present invention, a speed signal is generated using a path length and a speed command value calculated in advance, and this speed signal is smoothed using a digital filter. Because path interpolation is performed, an accurate trajectory command value for smooth speed control is generated, making it possible to perform accurate trajectory control that does not depend on the magnitude of speed. For this reason, especially in laser processing machines, it is possible to process minute circular arcs at high speed and with high precision.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of one embodiment of the trajectory control device of the present invention, Fig. 2 is a block diagram showing the hardware configuration of the device in Fig. 1, and Fig. 3 shows details of the speed control processing section. The block diagram shown in FIG. 4 is a flowchart showing its operation, and FIG. 5 (A). (B) is an explanatory diagram of the operation waveform of the speed control processing section, the sixth
7 is a block diagram showing the configuration of a conventional trajectory control device. FIG. 8 is a block diagram showing the configuration of the interpolation calculation section in FIG. 7. The figure is an explanatory diagram showing an example of its operation, and FIG. 10 is a block diagram showing the configuration of the smoothing processing section of FIG. 8. (1) is a command input section, (2) is an interpolation calculation section, (3) is a smoothing processing section, (4) is a servo drive section, (21) is a digital filter, (26) is a segment buffer memory, (27) (30) is a speed command generation unit, (33) is a segment end determination unit, and (35) is a proportional interpolation calculation unit. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Patent Attorney Muneharu Sasaki Figure 4 Figure 5 Figure 6 Figure 9 Figure 10 Procedure amendment (voluntary) 1. Indication of the case Patent Application No. 1982-292579 2. Name of the invention Trajectory control device 3. Relationship with the case of the person making the amendment Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mitsubishi Electric Corporation Representative Moriya Shiki 4 Agent address 5 Toranomon, Minato-ku, Tokyo "Claims" and "Detailed Description of the Invention" of the specification subject to the Chome 8-6 No. 56 amendment
6. Contents of amendment (1) The claims of the specification will be amended as shown in the attached sheet. (2) Page 2 of the specification, lines 12 to 17 “This is...
...It's done. ” shall be amended as follows. This consists of the amount of movement (X, Y), speed of movement (F), type of trajectory (straight line, circular arc, etc.), acceleration/deceleration control command value, etc.In addition, in the case of a circular arc, the circular arc relative to the starting point of the block It also includes the center coordinates (1, J) of (1, J). (3) Correct "this time" in line 3, line 15 of the specification to "this time." (4) Line 4, line 16 of the specification “X,” is replaced with “X,” l
Correct it with J. (5) Replace “j-0, 1, 2,” on page 5, line 5 of the specification with r
Correct as j-1, 2, 3J. (6) Correct “axis trace” on page 5, line 16 of the specification to “trajectory”. (7) Correct “axis trace” in the first line of page 6 of the specification to “trajectory”. (8) Correct “axis trace” on page 6, line 16 of the specification to “trajectory”. (9) "(ΔL)・Segment" on page 8, line 4 of the specification is corrected to "(ΔL), segment." (10) Correct “axis trace” in line 5 of page 13 of the specification to “trajectory”. (11) Figure 4 of the drawings shall be amended as shown in the attached amended drawings. Claims (Amendment) ``Path length calculation means for calculating the path length of a trajectory based on a given trajectory command value; A speed signal generating means that generates a signal, a digital filter that shapes the waveform of the speed signal based on the output of the speed signal generating means, and a moving component of the trajectory is calculated using the shaped speed signal and the trajectory command value. and an interpolation calculation means for sequentially calculating each drive shaft component of the movement component." Figure 4 Amended Drawing Procedure City Official Book C 11) 1 , Indication of the case Patent application No. 1982-292579 2, Name of the invention Trajectory control device 3, Person making the amendment Relationship to the case Patent applicant Address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (801) Mitsubishi Electric Co., Ltd. Representative: Moriya Shiki 4, Agent address: 5-8-6-5 Toranomon, Minato-ku, Tokyo Subject of amendment: ``Contents of amendment'' of the procedural amendment dated June 25, 1988
6. Contents of amendment (1) Procedural amendment dated June 25, 1986, page 2, No. 11
Correct the line “3rd line” to “3rd page”. (2) "Line 4, line 16" of page 2 of the procedural amendment, line 13, is amended to "line 17, page 4."that's all

Claims (1)

[Claims] Path length calculation means for calculating the path length of the axis trace based on a given trajectory command value, and speed signal generation means for generating a travel speed signal using the given speed command value and the output of the path length calculation means. and a digital filter that forms a speed signal waveform based on the output of the speed signal generating means, and a digital filter that calculates a moving component of the trajectory using the formed speed signal and the trajectory command value, and calculates the moving component of the moving component. An axis track control device comprising: interpolation calculation means for sequentially calculating each drive axis component.