JPS63236915A - Movement controller for coordinate measuring instrument - Google Patents

Abstract

PURPOSE:To perform speedy processing by storing and detecting path coordinates until the detection of a probe and then tracing back the stored path at the best speed. CONSTITUTION:A timer 12 inputs a read command clock to a microcomputer MC 11 at constant intervals of time by the actuation of the MC 11. The values of coordinate counters 13, 14, and 15 for respective X, Y, and Z axes are read with the read clock and stored in a memory 16 only when different from last read coordinates, thus updating the contents of the memory. When the probe 1 contacts a body to be measured, the MC 11 reads back the stored coordinate values in the memory 16 with a touch signal to determine the best speeds matching with the movement path of the probe 1. The determined respective axis speeds are supplied to a speed control circuit 17 and respective axis motors 21, 22, and 23 are driven through X, Y, and Z axis motor circuits 18, 19, and 20. Consequently, the probe 1 moves at the composite speed of respective axis speeds determined according to the rotating speeds of respective motors. Consequently, the speedy processing is performed.

Description

[Detailed description of the invention] (Technical field of invention) The present invention relates to a speed control device for a coordinate measuring machine.

(Background of the Invention) In a three-dimensional coordinate measuring machine, a probe moving device capable of safely moving the probe backward from a measurement point that is not visible from the outside is known from Japanese Patent Publication No. 18001/1983.

This device memorizes the moving speed of the probe sequentially when moving the probe to the measurement point, and when the probe reaches the measurement point, the direction signal is reversed by the contact signal obtained from the probe, and the memorized speed is sequentially stored from the opposite direction. The probe is read out and moved back along the outward path at the moving speed of the outward path.

Therefore, since this object can only be moved backward at the same speed as the forward movement, it has been impossible to perform processing at a higher speed.

(Objective of the Invention) An object of the present invention is to solve these drawbacks and provide a movement control device for a coordinate measuring machine that is capable of retracting a probe from a measurement point at high speed.

(Summary of the Invention) The present invention provides a movement control device for a coordinate measuring machine capable of moving a probe (1) that outputs a detection signal when it detects an object to be measured in two or more axes. storage means (2) capable of sequentially storing moving route coordinates up to the detection of the moving route coordinates; A reading means that can read out sequentially in the direction (
3), speed setting means (4) for sequentially setting an optimum driving speed along the movement route from the coordinates sequentially read out by the reading means; A movement control device for a coordinate measuring machine, comprising: a control means (5) for moving the probe backward from the driven object along the movement path up to the detection according to an optimum driving speed. .

(Example) FIG. 2 is a block diagram of one embodiment of the present invention.

The operation key 10 is one of a group of keys for issuing various commands, and when the operation key 10 is turned on, a reading start interrupt is input to the microcomputer 11. The read start interrupt causes the microcomputer 11 to start a timer 12 for generating a read command clock interrupt. The timer 12 is activated by the microcomputer 11 and inputs a reading command clock to the microcomputer 11 at fixed time intervals. Microcomputer 11
reads the values of the X-axis coordinate counter 13, Y-axis coordinate counter 14, and X-axis coordinate counter 15 by the interrupt of the read command clock that interrupts at regular intervals, and these values are the clock of the previous read command. The coordinates are stored in the memory 7 only when the coordinates are different from those read by the interrupt. The stored contents are updated sequentially.

To be more specific, when the probe 1 moves, the spatial coordinate values of the contact portion of the probe 1 change accordingly. These spatial coordinate values are read by an X-axis counter 13, a Y-axis counter 14, and a Z-axis counter 15.
When is stopped, each counter 13.14.15
The values of X-axis coordinate counter 13 and Y do not change.
If the values of the axis coordinate counter 14 and the X-axis coordinate counter 15 do not change due to interruptions before and after the reading command clock, it can be determined that the probe 1 is stopped.

For example, as shown in FIG. 2, the probe 1 is moved into the hole M of the object to be measured by manual scanning by the robot, and brought into contact with the innermost point P1 of the hole M along the trajectory N. Then, with the above-described configuration, the coordinate values on the trajectory N are stored in the memory 16 as movement route coordinates at fixed time intervals determined by the reading command clock.

When the probe l comes into contact with point P, a touch signal is output from the probe l and inputted to the microcomputer 11 as a touch signal interrupt. Microcomputer 11
reads out the coordinate values (for example, each coordinate value of the coordinate string of the trajectory N) stored in the memory 16 in response to the touch signal interruption in order from the last stored coordinate value, and reads out the movement path of the probe 1 (for example, , trajectory N), and determine the speed to be output to each axis. The determined speed of each axis is given to the speed control circuit 17, and is transmitted to the X-axis motor 2i, Y-axis motor 22, and Z-axis motor 23 through the X-axis motor circuit 18, Y-axis motor circuit 19, and Z-axis motor circuit 20.
is driven. As a result, each rotation of the X-axis motor 21 that moves the probe 1 along the X-axis, the Y-axis motor 22 that moves the probe 1 along the Y-axis, and the two-axis motor 23 that moves the probe 1 along the Z-axis. The probe 1 moves at a combined speed in each axis direction that is determined according to the number.

The moving speed of the probe 1 is set so that it faces in the tangential direction of the moving route (for example, the trajectory N).

The optimal speed setting along the above-mentioned travel route is as follows:
For example, this is done as follows. However, here, speed determination for a two-dimensional trajectory will be explained. Assume that the probe l moves from position K to A as shown in FIG. 4, and the coordinate values from position K to A are stored in the memory 16. When the probe l moves to position A and a touch signal interrupt is input to the microcomputer 1, the microcomputer 11 calculates a pseudo radius of curvature R( AB/2・Sinθ,
) and the velocity at position A with K as the constant, VA=K ff1=K (AB)/("Sin fl
m ).

Although Fig. 4 is a two-dimensional explanation, the same applies to a three-dimensional case.If the movement locus is approximated by a circular arc and the velocity V determined according to the radius of curvature is calculated for each position, for example,
A velocity distribution as shown in FIG. 5 can be obtained.

However, as can be seen in Figure 5, sudden speed changes make the operation of the control system unstable, so the appropriate acceleration and deceleration processing speeds are calculated, and the speed changes are as shown by the broken line in Figure 5. Control is performed so that it is continuous. This speed change, that is, the acceleration/deceleration gradient, is determined by the speed control circuit 17 changing the number of pulses per unit time corresponding to each axis according to a control command from the computer 11, and transmitting a level signal corresponding to the counted value of the pulses to each axis. It is finally determined by outputting to the motor circuits 18, 19, and 20.

Next, in order to organize the operations of the microcomputer 11, the flowchart shown in FIG. 6 will be explained.

The microcomputer 11 first determines whether or not a read start interrupt has been input. In step 60L, when the read start interrupt is input, the read command clock timer 12 is activated.
(step 61). After that, when a reading command clock is input (step 62), it is determined whether or not the coordinate data is the same as when inputting the previous clock (step 63). If the data is the same, the coordinate data will continue until the next clock is input. stop remembering. If the coordinate data are not the same in step 63, the values of the X-axis counter 13, Y-axis counter 14, and Z-axis counter 15 are stored in the memory 16 (step 64).

By the way, if the reading command clock is not input in step 62, it is determined whether or not a touch signal has been input (step 65), and when a touch signal is input, the stored order from the memory 16 is Sequentially in the opposite direction to
, Y, and Z coordinate values, and calculates the optimal speed from a plurality of adjacent coordinate values (step 66).Then, the acceleration/deceleration gradient is checked and commands are given so that the speed changes are as continuous and smooth as possible. The speed is corrected (step 67), and the command speed is output (step 68). Steps 66, 67, and 68 of 0 or more are performed until the output data is completed (step 69), that is, when the probe 1 returns to the starting point. , stop the timer 12 (step 7
0), prepare for the next read start interrupt.

As described above, according to the embodiment of the present invention, it is possible to drive the retracting path after contact with the probe to be the same path as the contact path,
Not only does it have the advantage of allowing the probe to be easily retracted and moved from measurement points that cannot be seen from the outside, but by calculating the optimal speed from the sequence of read points, it is possible to achieve optimal speed control with no waste. This makes it possible to achieve high throughput. Furthermore, in the embodiment of the present invention, if the stored point sequence (coordinate sequence) is stored as information for automatic measurement and repeated measurements, even complex measurements can be processed at high speed. Further, the reading timing is not based on the reading command clock 1, but it is also possible to take in coordinate values every fixed amount of detection movement, and it is also possible to take in every fixed amount of movement of each axis. Variations in data can be reduced depending on how the data is captured.

An example of the most efficient speed calculation method has been shown, but other methods are possible. All you have to do is select the calculation method that suits your drive device.

The probe described in the above embodiments was a so-called contact probe that outputs a touch signal as a detection signal when it comes into contact with the object to be measured, but when the distance to the object reaches a predetermined value, It may be a so-called non-contact type probe that outputs a detection signal when it detects the object to be measured. Examples of this type of non-contact probe include those that project a light spot onto an object to be measured and detect, based on the position of the reflected image, that the distance to the object has reached a predetermined value.

Further, in the flowchart of FIG. 6, step 70
may be placed immediately after step 65.

(Effects of the Invention) As described above, according to the present invention, since the probe of the coordinate measuring machine can be evacuated at high speed, it is possible to obtain a speed control device that enables rapid processing.

[Brief explanation of drawings]

Fig. 1 is a frame correspondence diagram of the present invention, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is an explanatory diagram showing the movement of the probe, and Fig. 4 is an optimum speed based on stored data of moving route coordinates. FIG. 5 is a graph showing the relationship between the obtained optimum speed and the command speed, and FIG. 6 is a flowchart of the microcomputer used in FIG. 2. (Explanation of symbols of main parts) ■...Probe, 2...Storage means 3...
Reading means, 4... Speed setting means 5... Control means, 11... Microcomputer 13... X-axis counter 14... Y-axis counter 15... Z-axis counter 16... Memory 17 ... Speed control circuit 21 ... X-axis motor 22 ... Y-axis motor 23 ... Z-axis motor

Claims (1)

[Claims] Two probes that output a detection signal when an object to be measured is detected.
A movement control device for a coordinate measuring machine capable of moving beyond an axis, comprising: a storage means capable of sequentially storing movement path coordinates until the probe detects the object to be measured; a reading means capable of sequentially reading out the stored moving route coordinates in a direction opposite to the stored order; and an optimum driving speed along the moving route being sequentially determined from the coordinates sequentially read out by the reading means. a speed setting means for setting the measured object; and a control means for moving the probe backward from the driven object along a movement path until the detected object according to the optimum driving speed after the probe detects the measured object. A movement control device for a coordinate measuring machine, comprising: