FAULT DETECTION AND FAULT DIAGNOSIS
Download as PPT, PDF1 like7,270 views
This document summarizes a case study report on fault detection and diagnosis of pneumatic actuators. It introduces pneumatic actuators and describes common faults that can occur in pneumatic valves, including in the air supply, supply line, piston/diaphragm actuators, valve stem sealing, and plug-seat combination. It then discusses models of pneumatic valves and presents results of detecting faults in intake air flow, manifold pressure, and manifold leaks using sensor data and residuals. The conclusions are that the developed fault detection strategy can effectively identify these three important valve faults.
FAULT DETECTION AND FAULT DIAGNOSIS
- 1. FAULT DETECTION AND FAULT DIAGNOSIS OF PNEUMATIC ACTUATORS:A CASE STUDY REPORT ON PMFD Submitted by: Anand Kumar 11RE60R04 Vikram Singh 11EE64R03
- 2. CONTENTS 1. Introduction 2. Faults of Pneumatic valves 3. Results 4. Conclusions 5. References
- 3. 1 INTRODUCTION Pneumatic actuator for linear motion with power supply: a) schematic; b) energy flow scheme; c) two-port representation. 1: AC motor, 2: air compressor, 3: pressure-relief valve, 4: air filter with water trap, 5: air storage (accumulator), 6: 4/3 proportional valve, electrical solenoid actuation, spring return, 7: double-rod cylinder; 8: diaphragm drive with spring return
- 4. CONTD.. Pneumatic actuators consist of an airflow valve and an actuating device transforms the pneumatic energy into mechanical energy. The valve is connected to the pneumatic pressure line manipulates the pressurized air flow to the actuating device. The valves are either proportional-acting valves or switching valves. Proportional acting valves allow a continuous manipulation of the airflow either electrically by two solenoids or pneumatically with one air flow modulator and return spring. Switching valves are electromagnetic devices and operate with PWM at high frequencies to generate actuator position.
- 5. 2 FAULTS OF PNEUMATIC VALVES Faults of pneumatic valves may arise in the air supply air supply line piston or diaphragm actuators valve stem sealing and plug–seat combination Cross-sectional view of a pneumatic valve with an electro-pneumatic position controller
- 6. Typical faults of pneumatic flow valves and fault-detection coverage in dependence on instrumentation- x:yes, 0: no
- 7. 2.1 MODELS OF PNEUMATIC VALVES The parameters for the chamber pressure are time-variant and depend on the motion and the position of the diaphragm.
- 8. The dynamics of the mechanical part of the valve, the diaphragm, the valve stem and the plug are governed by the balance of forces: where mv :mass of the stem and connected parts, cs : spring constant, dv ,fc :coefficients of the viscous and dry friction of the stuffing box and guidance Fext: external forces, mainly the force through the flowing fluid
- 9. RESULTS Sensor Fault on intake air flow Sensor Fault on Manifold pressure Fault in Manifold Due to air leak
- 10. CONCLUSIONS • The fault detection strategy is designed for three important faults as from manufacturer point of view. • Observed that after initial transient effect the performance of each residual is effective.
- 11. REFERENCES 1. J. A. F. Vinsonneaut, D. N. Shieldst, K. J. Bumhamt. Improved SI engine modeling techniques with application to fault detection . Pages 719-724, Proceedings of 2002 IEEE international Conference on Control Applications, September 18-20.2002 Glasgow, U.K. 1. R. Iserman. Fault Diagnosis Systems An introduction from fault detection to fault tolerance, Chapter 11 Fault detection with state observers and state estimation, Springer, Berlin. 1. Graham C. Goodwin, Stefan F. Graebe, Mario E. Salgado, Control system design, Chapter V Advanced SISO control, Prentice Hall, New Jersey 1990. 1. K.P. Mohandas. Modern control engineering, Sanguine Technical Publishers. Bengaluru. 2006.
Editor's Notes
- #2: PAGE 224 WOLOWICH