JPH07113544B2 - Movement control device for coordinate measuring machine - Google Patents

Description

TECHNICAL FIELD OF THE 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 retracting a probe from a measuring point invisible from the outside is known from Japanese Patent Publication No. 60-18001.

This one sequentially stores the moving speed of the probe when moving the probe to the measurement point, and when the probe reaches the measurement point, the direction signal is inverted by the contact signal obtained from the probe and the storage speed is sequentially reversed from the reverse direction. The probe is read out and moved backward along the outward path at the traveling speed of the outward path.

Therefore, since this device can be moved backward only at the same speed as the forward path, it was impossible to process it at a higher speed.

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

(Summary of the Invention) The present invention relates to a movement control device for a coordinate measuring machine capable of moving a probe (1) that outputs a detection signal when detecting an object to be measured in two or more axes, wherein the probe (1) is the object to be measured. A storage unit (2) capable of sequentially storing the movement route coordinates until the detection of, and a speed setting unit for sequentially setting an optimum driving speed along the movement route based on the stored movement route coordinates ( 4), and a control means (5) for moving the probe backward from the object to be measured along a movement path after the probe detects the object to be driven according to the optimum driving speed. It is a movement control device of a coordinate measuring machine characterized by having.

(Embodiment) FIG. 2 is a block diagram of an embodiment of the present invention.

The operation key 10 is one of a group of keys for performing various commands, and when the operation key 10 is turned on, a read start interrupt is input to the microcomputer 11. The read start interrupt causes the microcomputer 11 to activate a timer 12 for generating a read command clock interrupt. timer
When the microcomputer 12 is activated by the microcomputer 11, a read command clock is input to the microcomputer 11 at regular intervals. The microcomputer 11 uses the interrupt of the read command clock that interrupts at fixed time intervals, and the X-axis coordinate counter
13, the values of the Y-axis coordinate counter 14 and the Z-axis coordinate counter 15 are read, and stored in the memory 16 only when these values are different from the coordinates read by the interruption of the clock of the previous read command. The stored contents are sequentially updated.

More specifically, when the probe 1 moves, the spatial coordinate value of the contact portion of the probe 1 changes accordingly. These spatial coordinate values are X-axis counter 13, Y-axis counter 14, Z-axis counter
Although read by 15, the values of the counters 13, 14, 15 do not change when the probe 1 is stopped. Therefore, X-axis coordinate counter 13, Y-axis coordinate counter
14. If the value of the Z-axis coordinate counter 15 does not change due to the interruption before and after the read command clock, it can be determined that the probe 1 is stopped.

For example, as shown in FIG. 3, the probe 1 is moved into the hole M of the object to be measured by manual scanning by the joystick, and is brought into contact with the deepest point P ₁ of the hole M by the trajectory N. Then,
With the above-described configuration, the coordinate values on the locus N are stored in the memory 16 as movement path coordinates at regular time intervals determined by the read command clock.

When the probe 1 contacts the point P ₁ , a touch signal is output from the probe 1 and input to the microcomputer 11 as a touch signal interrupt. The microcomputer 11 sequentially reads the coordinate values stored in the memory 16 by the touch signal interrupt (for example, each coordinate value of the coordinate sequence of the trajectory N) from the last stored coordinate value to move the probe 1. The optimum speed along the route (for example, trajectory N) is set sequentially,
Determine the speed to output for each axis. The determined axis speeds are given to the speed control circuit 17, and the X-axis motor circuit 18, Y
X axis motor through axis motor circuit 19 and Z axis motor circuit 20
21, the Y-axis motor 22, and the Z-axis motor 23 are driven. As a result, the X-axis motor 21, which moves the probe 1 along the X-axis,
The probe 1 is moved at a combined speed in each axial direction that is determined according to the number of rotations of the Y-axis motor 22 that moves the probe 1 along the Y-axis and the Z-axis motor 23 that moves the probe 1 along the Z-axis.
Moves. The moving speed of the probe 1 is set so as to face the tangential direction of the moving path (for example, the trajectory N).

In addition, the optimum speed setting along the above-mentioned movement route is
For example, it is performed as follows. However, here, speed determination for a two-dimensional trajectory will be described. As shown in FIG. 4, the probe 1 moves from position K to A,
It is assumed that 16 stores the coordinate values of positions K to A. When the probe 1 is moved to the position A and the touch signal interrupt is input to the microcomputer 11, the microcomputer 11 pseudo-radius of curvature from the angle θ _B formed by the line segment ▼ and the line segment ▼. R (▲ ▼ / 2 · Sin
seeking theta _B), the velocity V _A at position A a constant as K, And calculate.

Although FIG. 4 is a two-dimensional description, it is the same in the case of a three-dimensional case. If the movement trajectory is approximated by an arc and the velocity V determined according to the radius of curvature is calculated for each position, for example,
The velocity distribution as shown in FIG. 5 can be obtained.

However, as can be seen in FIG. 5, a sudden speed change makes the operation of the control system unstable, so an appropriate acceleration / deceleration processing speed is calculated, and the speed change is as shown by the broken line in FIG. Then, control is performed so as to be continuous. This speed change,
That is, the acceleration / deceleration gradient is such that the speed control circuit 17 changes the number of pulses per unit time corresponding to each axis according to a control command from the computer 11, and the level signal corresponding to the count value of this pulse is given to each motor circuit 18, It is finally decided by outputting to 19, 20.

Next, in order to organize the operation of the microcomputer 11, the flowchart of FIG. 6 will be described.

The mylo computer 11 first determines whether or not a read start interrupt is input (step 60), and when the read start interrupt is input, activates the read command clock timer 12 (step 61). After that, when the read command clock is input (step 62), it is determined whether the coordinate data is the same as when the previous clock was input (step 63). If the same data, the coordinates are input until the next clock is input. Stop storing data. If the coordinate data is not the same in step 63, the values of the X-axis counter 13, the Y-axis counter 14, and the Z-axis counter 15 are stored (stored) in the memory 16 (step 64).

By the way, when the read command clock is not input in step 62, it is determined whether or not the touch signal is input (step 65). When the touch signal is input, the order stored in the memory 16 is stored. In the opposite direction to X, Y,
The Z coordinate value is read, and the optimum speed is calculated from a plurality of adjacent coordinate values (step 66). Then, the acceleration / deceleration gradient is checked, and the command speed is corrected so that the speed change is as continuous and smooth as possible (step 6).
7), command speed is output (step 68). The above steps 66, 67 and 68 are repeated until the output data is completed (step 68), that is, when the probe 1 returns to the starting point,
The timer 12 is stopped (step 70) to prepare for the next read start interrupt.

As described above, according to the embodiment of the present invention, it is possible to drive the receding path after contacting the probe with the same path as the contact path,
Not only is there an advantage that the probe can be easily retracted and moved from a measurement point that is not visible from the outside, but the optimum speed control can be achieved by calculating the optimum speed from the read point sequence. It becomes possible and high throughput can be realized. Further, in the embodiment of the present invention, if the stored point sequence (coordinate sequence) is stored as information of automatic measurement and repeated measurement, complicated measurement can be processed at high speed. Further, the reading timing does not depend on the reading command clock 1, and the coordinate value can be taken in every constant movement amount, and can also be taken in every constant movement amount of each axis. It is possible to reduce the variation of the data depending on how to take in the data.

An example of the most efficient speed calculation method has been shown, but other methods are possible. A calculation method suitable for the driving device may be selected.

The probe described in the above embodiments is a so-called contact type probe that outputs a touch signal that is a detection signal when it comes into contact with the object to be measured, but when the distance to the object to be measured reaches a predetermined value, the probe is detected. It may be a so-called non-contact type probe that outputs a detection signal when a measurement object is detected. As such a non-contact probe, there is a probe that projects a light spot on the object to be measured and detects that the distance to the object to be measured reaches a predetermined value depending on the position of the reflected image.

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

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

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claim 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 a probe, and FIG. 4 is an optimum speed from stored data of movement path coordinates. FIG. 5 is an explanatory diagram for explaining an example of obtaining the value, FIG. 5 is a graph showing the relationship between the obtained optimum speed and command speed, and FIG. 6 is a flowchart of the microcomputer used in FIG. (Description of symbols of main parts) 1 ... 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 (3)

[Claims] 1. A movement control device of a coordinate measuring machine capable of moving a probe that outputs a detection signal when detecting an object to be measured in two or more axes, wherein a movement path of a movement path until the probe detects the object to be measured. Storage means capable of sequentially storing coordinates, speed setting means for sequentially setting an optimum drive speed along the moving path based on the stored moving path coordinates, and the probe detects the object to be measured. After that, there is provided control means for moving the probe backward along the movement path from the object to be measured in accordance with the optimum driving speed, and a movement control device for the coordinate measuring machine. 2. The speed setting means has a reading means for sequentially reading the stored movement path coordinates in a reverse direction to the stored order by generation of a detection signal of the probe, The movement control device for a coordinate measuring machine according to claim 1, wherein an optimum driving speed along the movement route is sequentially set from the movement route coordinates that are sequentially read. 3. The coordinate measuring machine according to claim 1, wherein the driving speed is calculated based on a radius of curvature of the moving path obtained from the coordinates sequentially read by the reading means. Movement control device.