JPH05154746A - Tracer control device - Google Patents

Abstract

PURPOSE:To prevent the asynchronism between a tracer head and a cutter in a tracer control device driving the tracer head with an auxiliary shaft provided in superimposition over a feeding shaft relatively moving the cutter and a work. CONSTITUTION:The profiling speed command value Vx is converted into the position command value LXC via a synthesizing circuit 1 and an integrating circuit 3 and inputted to a backlash correcting circuit 4. The backlash correcting circuit 4 detects the direction of the profiling speed command value Vs when it reads the position command value LXC. When the direction of the profiling speed command value is reversed, the output of the position command value LXC is stopped until the profiling speed command value Vx to a tracer head is outputted by the shift quantity of the backlash quantity of a tracer head shaft. A main motor Xm 36 on the cutter side is not driven during this period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracing control device for grinding a work by a cutter while tracing a model with a tracer head, and more particularly to a tracing control device for delaying and moving the cutter to the tracer head.

[0002]

2. Description of the Related Art In a conventional tracing control device, a feed shaft of a cutter of a tracing machine is mechanically integrated with a tracer head. However, when the stylus of the tracer head hits a corner of the model, it becomes equivalent to a state in which the tracer head bites into the model temporarily due to the influence of machine inertia. For this reason, there is a problem that the cutter bites into the work by the same amount as the tracer head and the processing accuracy is reduced.

Therefore, the applicant of the present application has filed a Japanese Patent Application No. 3-35560 as a tracing control device for delaying a tool for a certain time with respect to a tracer head and tracing along the same path.

According to the tracing control device, an auxiliary shaft for driving the tracer head is provided so as to overlap with each of the feed shafts on each shaft of the machine tool, and the tracer head precedes the cutter by controlling the auxiliary shaft. Let the model follow. As a result, the biting of the tracer head in the shape-changing portion such as the corner portion of the model is detected, and the biting at the corner portion in the profile machining by the cutter is prevented in advance.

[0005]

By the way, the feed shaft and the auxiliary shaft have a backlash. Therefore, when the speed direction is reversed, the mechanical axis does not move by the amount of backlash even if the motor rotates. With this, the feed axis and auxiliary axis do not move as commanded.

In the past, correction control was performed for the backlash of the feed shaft, but no control was performed for the auxiliary shaft. Therefore, when the speed direction of the tracer head is reversed, the movement of the tracer head and the cutter are out of synchronization.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a profile control device capable of preventing the deviation of the synchronization between the tracer head and the cutter.

[0008]

According to the present invention, in order to solve the above-mentioned problems, in a tracing control device for driving a tracer head by an auxiliary shaft provided so as to overlap with a feed shaft for relatively moving a cutter and a work, Movement command signal output means for outputting a movement command signal for the auxiliary shaft of the tracer head according to the displacement amount of the stylus, tracer head movement control means for receiving the movement command signal and controlling the movement of the tracer head, and When the movement command signal is received, the movement of the tracer head is delayed to control the movement of the feed axis of the cutter, and the movement direction of the cutter is controlled by the movement control signal. Signal supply stopping means for stopping the supply of the movement command signal to the cutter movement control means by the movement amount of the backlash amount, It is If There controller and wherein is provided to have.

[0009]

When the command movement direction is reversed, the signal supply stopping means stops the supply of the movement command signal to the cutter movement control means by the movement amount of the backlash amount of the auxiliary axis, and the auxiliary axis feeds by the backlash. Prevents misalignment between the shaft and auxiliary shaft.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing the overall configurations of the profile control device and the profile machine tool of the present invention. The profile control device 20 includes a CPU 21 that controls the entire device by performing a profile calculation, a ROM 22 that stores a control program, a RAM 23 that temporarily stores input / output data, and a non-volatile memory 24. The non-volatile memory 24 is backed up by a battery (not shown), and stores various parameters input from the operation panel 25, such as a tracing direction and a tracing speed.

The servo amplifiers 26 and 27 receive the feed axis drive command from the profile control device 20 and drive the main motors such as the X axis and Z axis. Also, the servo amplifier 2
8 and 29 receive auxiliary axis drive commands from the profile control device 20 and drive sub-motors such as X-axis and Z-axis.
In order to enable three-dimensional profile machining, the profile machine tool 30 is provided with auxiliary axes that overlap each other in parallel with the feed axis for each of the three axes including the Y axis (not shown). Then, the tracer head 31 on the tracing machine tool 30 side detects the displacement amounts εx, εy, and εz in the X-axis, Y-axis, and Z-axis directions generated by the stylus 32 at its tip contacting the model 33. It is input to the control device 20.

The cutter 34 is attached to the column 35,
The column 35 is moved in the Z-axis direction by the main motor 36zm. The column 35 has a sub motor 37zs.
And 37xs are installed, these sub motors 3
By 7zs and 37xs, the tracer head 31 further moves in the Z-axis direction and the X-axis direction in superposition with the movement of the column 35. The work 38 is fixed on the table 39 together with the model 33, and the table 39 is moved in the X-axis direction by the main motor 36xm.

The main motors 36xm and 36zm rotate according to the feed shaft drive commands Vxm and Vzm. On the other hand, the sub motors 37xs and 37zs rotate according to the speed command values Vxs and Vzs calculated from the following speed command values, and drive the tracer head ahead of the cutter head.

In the profile machine tool 30 having the above configuration, the profiler controller 20 corrects the path that the tracer head 31 has passed through, while the cutter 34 passes through with a certain delay. That is, the tracer head 31 follows the model 33 before the cutter 34, and the cutting path by the cutter 34 is corrected according to the biting state of the tracer head 31. Therefore, when a bite occurs, the movement of the cutter 34 is not forcibly stopped and the work 38
The path is corrected so that it does not cut into and cut, and continuous profile processing is executed.

FIG. 1 is a block diagram showing the main control elements of the tracing control device. Although only the configuration of the portion corresponding to the X-axis is shown in the figure, the control elements for the Y-axis or the Z-axis are similarly configured.

The tracing speed command value Vx in the X-axis direction is obtained at a constant calculation cycle by tracing the displacement amount detected by the tracer head. The following speed command value Vx is sent to the synthesis circuit 1. The correction command value VxC is input to the synthesis circuit 1 from the correction calculation circuit 2 in addition to the following speed command value Vx. The correction calculation circuit 2 uses the tracer head pressed against the model 33 to generate an X-axis displacement amount εx.
Based on the above, the correction command value VxC is determined for each predetermined calculation cycle.

In the correction calculation circuit 2, when the X-axis displacement amount input in a certain calculation cycle is εxi, the correction command value VxCi at this time is calculated by the following equation (1). VxCi = εxi × G / s (1) Here, G is a correction gain and s is a calculation time. The correction gain G is determined according to the bite amount of the tracer head and the diameter of the cutter 34 for processing the work, and is set from the outside. In this way, in the synthesizing circuit 1, the profile speed command value Vx is synthesized with the correction command value VxC and is input to the integrating circuit 3. Then, it is converted into a position command value LxC by the integration circuit 3 and input to the backlash correction circuit 4. The integral gain of the integrating circuit 3 is K1, and S is a Laplace operator.

The backlash correction circuit 4 detects the direction of the speed command value Vx by reading the position command value LxC. Then, if the direction of the profiled speed command value Vx is not reversed, the position command value LxC is output to the FIFO memory 5 as it is. On the other hand, in the case of reversing, the output of the position command value LxC is stopped until the tracing speed command value Vx to the tracer head 31 is output for the movement of the backlash amount of the tracer head shaft.

The position command value LxC thus output from the backlash correction circuit 4 is input to the FIFO memory 5. The position command value LxC is stored as a plurality of feed axis drive command data in the order in which they are input to the FIFO memory 5, and when the storage capacity overflows, the data first input is output in order. Therefore, the position command value Lx
C is the X-axis drive command delayed by the required time, and is X
It is output to the shaft main motor 36Xm. In addition, this FI
The delay time of the FO memory 5 is freely set by a delay time setting signal from the outside according to the distance that the tracer head should precede the tool.

The position command value LxC is determined by the main motor 36X.
While being sent to m, it is sent to the arithmetic circuit 7 via the constant circuit 6. In the constant circuit 6, the position command value LxC is multiplied by a predetermined gain G1 and converted into a speed command subtraction signal. The arithmetic circuit 7 follows this subtraction signal to obtain the speed command value V
It is subtracted from x and output as the speed command value VsC to the X-axis sub motor 37Xs. This speed command value VsC is corrected by the calculation circuit 8 for correction, and the X-axis sub motor 37Xs is corrected.
Sent to.

The following speed command value Vx is sent to the synthesis circuit 1 and the subtraction circuit 7 as described above, while the integration circuit 9 is used.
Also sent to. Then, it is converted into a position command value by the integrating circuit 9 and input to the arithmetic circuit 10. The integral gain of the integrating circuit 9 is K2, and S is a Laplace operator.
The arithmetic circuit 10 determines the FIFO memory 5 from the position command value.
The theoretical leading amount L is obtained by subtracting the position command value LxC from, and is input to the register circuit 11. This theoretical advance amount L indicates the current value of the instruction advance amount commanded by the control device 20 for the tracer head that should precede the movement of the cutter 34. On the other hand, the actual preceding amount La of the tracer head is stored in the register circuit 12 as a feedback signal fed back from the X-axis sub motor 37Xs.

The outputs of these two register circuits 11 and 12 are compared in the arithmetic circuit 13. That is, the theoretical leading amount L is input as the addition signal and the actual leading amount La is input as the subtraction signal to the arithmetic circuit 13, where the X-axis submotor 3 is input.
A 7Xs correction signal is calculated as the difference between these L and La. The output of the arithmetic circuit 13 is multiplied by a predetermined gain G2 in the constant circuit 14 to form a speed command, which is input to the arithmetic circuit 8 for correction as an addition signal.

In this way, when the profile speed command value Vx that has been distributed and calculated is output to the cutter side, the FIFO memory 5
The feed axis drive command is output to the main motor 36Xm after being delayed by the required time. And tracer head 3
The relative movement between 1 and the model 33 is based on the main motor 36Xm.
Is controlled to be equivalent to the following speed command value Vx by the sub-motor 37Xs which is superposed on the movement of and is controlled. Therefore, the tracer head 31 can precede the cutter 34 to make the model 33 line up, and the cutter 34 can be controlled by a corrected path command different from the path of the tracer head 31 to the model 33.

Further, in the present embodiment, feedback control is applied to the advance amount for each axis so that the actual advance amount La is always adjusted to the theoretical advance amount L, so that the command speed fluctuation based on the model shape changes. Even if there is, the movement locus of the cutter 34 is always controlled by a path whose displacement amount is corrected from the tracer head 31.

Further, in this embodiment, the tracer head 3
If the speed direction of the speed command value Vx following 1 is reversed, the backlash correction circuit 4 causes the main motor 3
Since the supply of the position command value LxC to 6Xm is stopped, the movement of the cutter 34 according to the amount of backlash of the tracer head 31 is stopped. This prevents the tracer head 31 and the cutter 34 from being out of synchronization.

FIG. 3 is a flow chart showing a correction control procedure by the backlash correction circuit 4. [S1] Based on the position command value LxC from the integrating circuit 3, it is judged whether or not the direction of the following speed command value Vx is reversed. If it is reversed, the process proceeds to step S2, and if not, the process proceeds to step S7. .. [S2] The accumulated value Xr of the position command value LxC of the tracer head 31 after the reversal of the profile speed command value Vx is accumulated.

[S3] It is judged whether the reversal direction of the profile speed command value Vx is the plus direction or the minus direction. If it is the plus direction, the process proceeds to step S5, and if it is the minus direction, the process proceeds to step S4. [S4] It is determined whether or not the accumulated value Xr is between 0 and a predetermined value −Bx corresponding to the backlash amount, and if so, the process proceeds to step S6, and if not, step S7.
Proceed to. [S5] It is determined whether the accumulated value Xr is between 0 and a predetermined value Bx corresponding to the backlash amount. If so, the process proceeds to step S6, and if not, the process proceeds to step S7.

[S6] The output of the position command value LxC to the FIFO memory 5 is stopped, and the movement command to the main motor 36Xm is stopped. Then, the process returns to step S2. [S7] The output of the position command value LxC to the FIFO memory 5 is started, and the movement command to the main motor 36Xm is started.

In this correction control procedure, the FIF
Although the output of the position command value LxC to the O memory 5 is stopped based on the accumulated value Xr of the position command value LxC of the tracer head 31, it is performed by setting the time corresponding to the backlash amount of the tracer head 31. Good.

[0030]

As described above, according to the present invention, when the command movement direction is reversed, the signal supply stopping means supplies the movement command signal to the cutter movement control means by the movement amount of the backlash amount of the auxiliary shaft. To stop. As a result, the cutter does not move by the amount of the backlash of the tracer head, so the synchronization between the tracer head and the cutter does not shift.

[Brief description of drawings]

FIG. 1 is a block diagram showing main control elements of a profile control device of the present invention.

FIG. 2 is a block diagram showing an overall configuration of a profile control device and a profile machine tool.

FIG. 3 is a flowchart showing a correction control procedure by a backlash correction circuit.

[Explanation of symbols]

 1 Synthesis Circuit 2 Correction Operation Circuit 4 Backlash Correction Circuit 5 FIFO Memory 7 Operation Circuit

Claims (3)

[Claims] 1. A tracing control device for driving a tracer head by an auxiliary shaft that is provided so as to overlap with a feed shaft that relatively moves a cutter and a work, and moves the tracer head with respect to the auxiliary shaft according to the displacement amount of a stylus. A movement command signal output means for outputting a command signal, a tracer head movement control means for receiving the movement command signal to control the movement of the tracer head, and a movement command signal for delaying the movement of the tracer head. When the cutter movement control means for controlling the movement of the cutter feed axis and the instruction movement direction by the movement instruction signal are reversed, the movement to the cutter movement control means by the movement amount of the backlash amount of the auxiliary shaft is applied to the cutter movement control means. A profile control device comprising: a signal supply stopping means for stopping the supply of a movement command signal. 2. The profile control device according to claim 1, wherein the movement command signal is a profile speed command value. 3. The tracing control device according to claim 1, wherein the movement command signal is a position command value.