Design of Fault Diagnosis Instrument for Speed Control System Based on Virtual

Instrument Di Chang-an, Jiang Dong-dong, Kong De-ren

Nanjing University of science and technology e-mail:dichangan@hotmail.com

Abstract: The operating status of the Electronic Speed Controller and the engine of the cannon needed to be evaluated and checked in ordinary maintenance, examination and repair. A useful fault diagnosis system for

Electronic Speed Controller was designed by LabVIEW. The system was composed by magnetoelectric spin speed sensor, junction box, PWM driven module, PCI1802 multi-function card and Apolo530 industry control portable computer. It could be used to measure and simulate

the signal of the magnetoelectric spin speed sensor or the

executor and also could be used to diagnose the faults of the

sensor, adjust board and executor of the Electronic Speed

Controller. Reliability and convenience of the system was

showed in the simulation running experiment.

Key words: Electronic Speed Controller, fault diagnosis,

signal simulation

I. INTRODUCTION The work efficiency of the cannon is affected by the

running state of the cannon Electronic Speed Controller, the running status of the Electronic Speed Controller and the engine need to be evaluated and checked in ordinary maintenance, examination and repair. The Electronic Speed Controller system of the cannon is based on close loop control system controlled by PID, it is difficult to field maintenance personnel to maintain quickly and precisely only by existing repairing tools. So it is very necessary to develop a fault diagnosis instrument which fits for the examination and repair of the Electronic Speed Controller system to the characteristic of the Electronic Speed Controller and the engine of cannon.

A useful fault diagnosis system of Electronic Speed Controller is designed by LabVIEW to the characteristic of the Electronic Actiyator, which can measure and simulate the signal of the magnetoelectric spin velocity sensor or the executor and can also diagnose the faults of

sensor, adjust board and executor of the Electronic Speed Controller.

II. OPRINCIPLE OF THE ELECTRONIC SPEED

CONTROLLER System composing and operating principle were

showed in fig.1. The spin speed is set by the spin speed adjusting potentiometer (according to amplitude controlled by potentiometer). The value of the amplitude was converted into relative current by the controller to control the executor, and the valve was opened by executor, and the engine was driven. The speed of the engine measured by spin speed sensor is transferred to Electronic Speed Controller, and compared with the amplitude value of the electronic speed system by Electronic Speed Controller. The PWM signal was corrected by the warp gotten from before to control spin speed.

Fig 1: Operating principle graph of the Electronic Speed Controller

III. COMPOSING OF THE DETECTION SYSTEM The system was composed by magnetoelectric spin

speed sensor, junction box, PWM driven module, PCI1802 multi-function card(32 channels ,16 bit,110kHz, fixed in PCI slot of the industry control computer, 2 channels for D/A) and Apolo530 industry control portable computer. The hardware composing diagram is showed in fig.2. For the convenience of fixing and repair in wartime, the structure of the Electronic

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DOI 10.1109/CDEE.2010.69

337

Speed Controller has been analyzed carefully, and a special junction box has been designed that different ways of connecting of the navigate plug has been used which ensure the reliability of the connection with no affecting the working of the mechanical. 220VAC is been used in off-line-detection. 220VAC that converted from field 12VDC by convertor is been used in on-line-detection.

Fig.2 System composition diagram

IV. SOFTWARE DESIGN

A. Flow Chart of Software

The software was divided into two parts: off-line-detection and on-line-detection. The requests of the on-line-detection includes detecting the output signal of the magnetoelectric speed sensor, calculating the speed of the engine, and detecting PWM signal and calculating the duty cycle, frequency, and amplitude of it. The requests of the off-line-detection include detecting the signal of the magnetoelectric speed sensor and the corresponding PWM signal of it, simulating PWM signal and analyzing corresponding movements of the executor. The flow diagram of the software is showed in fig.3.

Fig.3 The flow diagram of software

B. Soft Panel Design

This virtual instrument software was programmed by graph programming language LabVIEW 7.1.

The system application software was consisted of 3 major parts: off-line-detection module (data simulation), on-line-detection module (data capture) and data processing module.

The application diagram and soft panel was designed to the characteristics of the parameters and detection request. The soft panel was consisted of off-line speed controller detection module (simulating sine wave and acquiring data), off-line executor detection module (simulating PWM wave), on-line speed controller detection module (acquiring PWM signal), on-line sensor detection module (acquiring sine signal) and data analyzing module, as shown in Fig4.

Fig.4 Front panel of software

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C. Program Chart

The application software was designed modular; the software is consisted of 3 modules: signal simulating module (off-line speed controller detection and off-line executor detection), acquisition module (on-line sensor detection and on-line speed controller detection) and data processing module. The flow diagram of the data acquisition module is showed in fig.5.

Fig.5 The flow diagram of the data acquisition module

In the first frame, the function of the program was reading the former parameter automatically to avoid the resetting of the parameters on every working time. The Data Acquisition Card was initialed in frame 2. In the third frame, it should be judged first according to the state of the self-detection program. Initialing Data Acquisition Card, scale setting, data acquiring and etc. are carrying out if the result of the self-detection program is “YES”.

The signal was acquired by the Data Acquisition Card which driven by industry control computer to judge the reason of the fault.

The signal that acquired by the Data Acquisition

Card is transferred to computer to judge the reason of the fault and submit the clue by data fuse program for the intelligent and automatic of the Surveillance.

Modularized structure of the program, which has functions like parameter setting remembering, operation reminding, parameter setting automatically and etc, ensure the reliability and accuracy of the movements.

A self-recording unit was designed which can judge if there was any fault of the engine intelligently and can record the reason to the hard disc of the computer automatically.

V. THE TEST OF THE SYSTEM The set was used in the experiment on the cannon

to test the reliability and accuracy of the system. Parameter setting of every channel was: Sampling rate 800kHz, Sample length 2kW/CH. It simulated the sine signal (the output waveform of the magnetoelectric speed sensor), PWM signal and etc. to the characteristic of the cannon Electronic Speed Controller in the experiment. The testing waveform is showed in fig.6.

Fig.6 The sine signal of the sensor and two channels PWM signal of

speed controller

VI. CONCLUSION There was obvious characteristic on the system: • The sine signal of the magnetoelectric

speed sensor and the PWM signal of the

Electronic Speed Controller to the executer can be simulated by the instrument, and the PWM signal of the controller and the corner of the executer can be checked by virtual instrument technology.

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• The output signal of the magnetoelectric speed sensor and the working current signal of the executer can be checked to realize the fault diagnosis of the sensor, adjusting board and executer of the speed controller.

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LABVIEW, OURNAL OF QINGHUA

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