Feedback control numerical machine tool and method thereof

Patent metadata

Field	Value
Publication number	US-9956661-B2
Application number	US-201414582640-A
Country	US
Kind code	B2
Filing date	Dec 24, 2014
Priority date	Nov 20, 2014
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A feedback control numerical machine tool and a method thereof are provided. The machine tool includes at least two spindles, an acoustic frequency detecting module, at least two spindle position detecting modules, and a control module. The spindles machine a workpiece. The acoustic frequency detecting module detects an acoustic frequency of the spindles when machining the workpiece. The spindle position detecting modules detects position information of the spindles when machining the workpiece. The control module acquires the acoustic frequency and the position information of the spindles, monitors whether any of the spindles chatters according to the acoustic frequency of the spindles, and performs chattering avoidance to the spindle that chatters according to the position information of the spindles. As such, the present disclosure performs chattering monitoring to a plurality of spindles and avoids the chattering immediately.

First claim

The invention claimed is:

1. A feedback control numerical machine tool, comprising:
at least two spindles that machine a workpiece;
an acoustic frequency detector comprising at least one first microphone configured to detect an acoustic frequency of the at least two spindles when machining the workpiece;
at least two spindle position detectors configured to correspond to the at least two spindles, respectively, and detect position information of the at least two spindles when machining the workpiece; and
a processor connected to the acoustic frequency detector and the at least two spindle position detectors, and configured to acquire the acoustic frequency and the position information of the at least two spindles, monitor whether at least one of the at least two spindles chatters according to the acoustic frequency of the at least two spindles, wherein the processor has a numeric control unit, the numeric control unit includes a plurality of working program segments having mechanical coordinates of the at least two spindles, and the working program segments having the mechanical coordinates are uploaded by batches to perform chattering avoidance,
wherein the numeric control unit configured to perform the chattering avoidance by adjusting a rotation speed, a feeding rate or a cutting depth of the spindle that chatters according to the position information of the at least two spindles.

2. The feedback control numerical machine tool of claim 1 , wherein the at least two spindle position detectors are a microphone array consisting of a plurality of second microphones.

3. The feedback control numerical machine tool of claim 1 , wherein the processor has a signal converting unit configured to convert the acoustic frequency and the position information of the at least two spindles from an analog format to a digital format.

4. The feedback control numerical machine tool of claim 1 , wherein the processor has a chattering recognition unit configured to determine whether the acoustic frequency of the at least two spindles is a predefined acoustic frequency or within an acoustic frequency range, and determine that at least one of the at least two spindles chatters when determining that the acoustic frequency of the at least two spindles is the predefined acoustic frequency or within the acoustic frequency range.

5. The feedback control numerical machine tool of claim 1 , wherein the processor has a spindle recognition unit configured to recognize a variation value of acoustic magnitudes of the at least two spindles, and the spindle that chatters according to the position information of the at least two spindles that corresponds to the variation value of acoustic magnitudes.

6. The feedback control numerical machine tool of claim 1 , wherein the processor has a chattering avoidance deciding unit configured to decide a chattering avoidance mode of the spindle that chatters.

7. The feedback control numerical machine tool of claim 1 , wherein the numeric control unit is configured to adjust a chattering avoidance mode of the spindle that chatters.

8. The feedback control numerical machine tool of claim 1 , further comprising a chattering frequency acquisition module connected to the processor and configured to adjust an initial value of the acoustic frequency or an acoustic frequency range causing the spindle chatters according to a frequency response function or a precutting method.

9. The feedback control numerical machine tool of claim 1 , further comprising at least one signal control unit connected to the processor and the at least two spindles, and configured to allow the processor to perform chattering avoidance to the spindle that chatters through the signal control unit.

10. A method of feedback control numerical machine, comprising:
detecting an acoustic frequency of at least two spindles when machining a workpiece by an acoustic frequency detector comprising at least one first microphone;
detecting position information of the at least two spindles when machining the workpiece by at least two spindle position detectors;
acquiring the acoustic frequency and the position information from the acoustic frequency detector and the at least two spindle position detectors by a processor, monitoring whether at least one of the at least two spindles is chattered by the processor according to the acoustic frequency of the at least two spindles, wherein the processor has a numeric control unit, the numeric control unit includes a plurality of working program segments having mechanical coordinates of the at least two spindles, and the working program segments having the mechanical coordinates are uploaded by batches to perform chattering avoidance; and
performing the chattering avoidance by adjusting a rotation speed, a feeding rate or a cutting depth of the spindle that chatters according to the position information of the at least two spindles.

11. The method of claim 10 , wherein the at least two spindle position detectors are a microphone array consisting of a plurality of second microphones.

12. The method of claim 10 , further comprising converting the acoustic frequency and the position information of the at least two spindles from an analog format to a digital format.

13. The method of claim 10 , further comprising determining whether the acoustic frequency of the at least two spindles is a predefined acoustic frequency or within an acoustic frequency range, and determining that at least one of the at least two spindles chatters if the acoustic frequency of the at least two spindles is determined to be the predefined acoustic frequency or within the acoustic frequency range.

14. The method of claim 10 , further comprising recognizing a variation value of acoustic magnitudes of the at least two spindles, and recognizing the spindle that chatters according to the position information of the at least two spindles that corresponds to the variation value of acoustic magnitudes.

15. The method of claim 10 , further comprising deciding a chattering avoidance mode of the spindle that chatters by a chattering avoidance deciding unit.

16. The method of claim 10 , further comprising adjusting a chattering avoidance mode of the spindle that chatters by the numeric control unit.

17. The method of claim 10 , further comprising acquiring an initial value of the acoustic frequency or an acoustic frequency range causing the spindle chatters according to a frequency response function or a precutting method.

18. The method of claim 10 , further comprising performing chattering avoidance to the spindle that chatters by at least one signal control unit.

Assignees

• Ind Tech Res Inst

Inventors

• Hwang Tsung-Ling
• Luo Tzuo-Liang
• Lin Chin-Te
• Liang Shuo-Peng
• Peng Ta-Jen

Classifications

• G05B2219/41256

  Chattering control · CPC title

• G05B19/404

  characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia (G05B19/19, G05B19/41 take precedence) · CPC title

• B23Q15/12 Primary

  Adaptive control, i.e. adjusting itself to have a performance which is optimum according to a preassigned criterion · CPC title

• G05B2219/49105

  Emitted noise of tool · CPC title

• G05B2219/37337

  Noise, acoustic emission, sound · CPC title