JPS6159863B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tracing control system that performs tracing control with an economical configuration.

Tracing control involves processing while detecting the shape of the model, and since the shape of the model generally does not have large changes in shape, it is sufficient to use a processor that performs the tracing calculations even if it does not have very high-speed calculation functions. It was hot. However, some models have sudden changes in the model shape, such as corners, so the tracing calculations corresponding to these sudden changes must be performed at high speed. , I had to deal with sudden changes in the model shape. Therefore, an expensive processor is required, resulting in the disadvantage that the entire device becomes expensive.

The present invention improves the above-mentioned conventional drawbacks, and provides a processor with high scanning speed for models that do not have sudden changes in shape.
The purpose of this is to make it possible to perform copying calculations even on parts where the model shape changes suddenly, thereby achieving economy. Examples will be described in detail below.

The present invention detects a sudden change in the model shape, and sets the copying feed rate for the sudden change to be slower than the normal copying feed speed, so that even a processor with a low calculation speed can execute the copy calculation. FIG. 1 is a block diagram of an embodiment of the present invention. In the figure, TH is a tracer head, ADX, ADY, and ADZ are AD converters, ARC is a copy calculation circuit, DC is a distribution circuit, ADD is an adder,
DAX, DAY are DA converters, DVX, DVY are drive circuits, MX, MY are motors, MT is mechanical moving parts, SEL
1, SEL2 is the selector, READ is the reading circuit,
ART is an arithmetic circuit, ACC is an accumulation circuit, COMP is a comparison circuit, REG, REG1, REG2 are registers,
MUL is a multiplier, F is a feed pulse circuit, and the copying calculation circuit ARC, distribution circuit DC, etc. correspond to the processor.

The shape of the model is detected by the tracer head TH, and the displacement signals ε _x , ε _y , ε _z in each axial direction are converted into digital signals by the AD converters ADX, ADY, ADZ, and the tracing calculation circuit ARC adjusts the calculation speed. Read the digital signal at the corresponding period. Following this tracing calculation circuit ARC, the displacement direction signal sinθ,
cosθ, displacement signal ε=√ _x ² + _y ² + _z ² ,
Difference signal Δε=ε−ε ₀ with reference displacement amount ε ₀ and absolute value signal of the difference signal |Δε|=|ε−ε ₀ |
Find the normal direction velocity signal V _N =K _N (ε−ε ₀ )
and tangential velocity signal V _T =−K _T · |ε−ε ₀ |
is calculated and added to the distribution circuit DC. Such calculations can be performed by well-known digital calculation means.

The distribution circuit DC distributes the normal velocity signal V _N and the tangential velocity signal V _T into an X-axis velocity signal V _X and a Y-axis velocity signal V _Y using the displacement direction signals sin θ and cos θ, Drive circuits DVX and DVY convert motors MX and MY to analog signals using PAY.
Driven by

The arithmetic circuit ART reads the output digital signals of the AD converters ADX, ADY, ADZ selected by the selector SEL1.
The output digital signals of ADX, ADY, and ADZ are read by the arithmetic circuit ARC and read n times at a cycle shorter than the one cycle period in which the speed signals V _X and V _Y are output. For the displacement signal ε _x , the calculation circuit ART calculates Δε _xi = ε _xi-1 −ε _xi ……(1) Perform the calculation. Such operations are performed using registers.
By setting ε _xi and ε _xi-1 in REG1 and REG2, n-time accumulation can be performed using the accumulator ACC.

Further, an arbitrary number of setting values are set in the register REG, and the comparison circuit COMP compares this setting value with the contents of the accumulator ACC, and controls the selector SEL2 based on the comparison result. selector
Override values A, B, and C are added to SEL2, and the override value selected by the output of the comparison circuit COMP is added to the multiplier MUL.
For example, as A>B>C>D, A% when A≦Δε _x <B (for example, 90%) B% when B≦Δε _x <C (for example, 70%) C% when C≦Δε _x <D (for example, 50%), a percentage override is applied that corresponds to each condition.

The multiplier MUL multiplies the constant value signal from the feed pulse circuit F by an override value, and the adder ADD adds the result to the tangential velocity signal V _T . In this case, the tangential speed signal V _T is expressed as V _T =-K _T · |ε-ε ₀ | as described above, so the speed signal is applied to the distribution circuit DC by adding the output of the multiplier MUL. is a small value. In other words, the scanning feed speed by motors MX and MY is reduced.

Also, the n-time accumulated value of the accumulator ACC will be a small value if there is little change in the shape of the model, and none of the conditions for the comparison circuit COMP mentioned above is satisfied, so the output of the multiplier MUL will be zero, Since the tangential velocity signal V _T output from the copying calculation circuit ARC is directly applied to the distribution circuit DC, the normal copying feed speed is achieved. Note that the contents of the accumulator ACC are cleared every n times. Furthermore, it is preferable to cancel the above-mentioned override when the override condition does not occur a predetermined number of times in succession. It can be realized.

As explained above, the present invention converts the analog displacement signal from the tracer head TH into a digital signal during one cycle in which the processor reads the input digital signal and outputs the calculation result.
The digital signal is read at a cycle shorter than the one cycle, and the increment of the digital signal is determined by an arithmetic circuit such as ART,
When this increment becomes larger than the set value, that is, when it corresponds to a sudden change in the model shape, the profiling feed speed is overridden and decelerated, so the profiling feed speed for the sudden change becomes slower and the processor is not able to process enough data. It is possible to carry out scanning control by executing scanning calculations, and even with a processor whose calculation speed corresponds to the normal scanning feed rate, scanning control can be performed with high precision for a portion of sudden shape change. Therefore, since an inexpensive microprocessor can be used, there is an advantage that the configuration can be made economical.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG.
The figure is an explanatory diagram of a displacement signal. TH is tracer head, ADX, ADY, ADZ are
AD converter, ARC is copy calculation circuit, DC is distribution circuit, DAX, DAY, DAZ is DA converter, DVX,
DVY is the drive circuit, MX, MY is the motor, MT is the mechanical moving part, ART is the calculation circuit, REG, REG1, REG
2 is a register, ACC is an accumulator, COMP is a comparison circuit, MUL is a multiplier, and ADD is an adder.

Claims (1)

[Claims] 1. It has a processor that converts the analog displacement signal from the tracer head into a digital signal and calculates the speed signal of each axis by calculating the digital signal.
In a copying control method in which the output signal of the processor is converted into an analog signal to drive a motor to perform copying feed, during one cycle in which the processor reads the digital signal, performs calculations, and outputs the result. , the digital signal is
A scanning control method characterized by determining an increment in the digital signal by reading it at a shorter period than a cycle, and decelerating the scanning feed speed when the increment exceeds a set value.