Research On Detection And Diagnosis System For Elevators Fault

The market demand of elevators keeps increase as modern cities develop rapidly. And customers require the elevator control system to be of higher reliability and the malfunction to be easier to be detected and addressed. The elevator control system with computer and high performance make it convenient to monitor and diagnose the system. A fault detection system based on CAN technology and an expert fault diagnosing system are proposed in this paper.A detailed analysis of the elevator components and its operation principle is first presented. Elevator fault characteristics are concluded according to analysis of fault modes and fault consequences. Faults are analyzed by means of an improved fault tree analysis, and several fault trees are built for every kind of faults, then make down-way quantity analysis with the minimal cut set theory. Based on the expert system which is expressed with production and framework, the rule base, assertion base, backward base, fact base, and catalogue base are built. A overall-forward part-backward reasoning way is designed and an expert system reasoning machine is built with improved and-or tree deep priority searching strategy. Uncertainty reasoning algorithm is presented. The expert function is realized by Access data base technology and VB language.The principle of safety loop and fault mode is discussed at length. A fault detection device based on CAN technology is designed. The device can pick up fault signal and do simple signal analysis which is good for ultimate fault diagnosing. According to control principle of elevator and its velocity curve generation method, a sine velocity curve based on time and distance is designed. An elevator monitoring system is developed. The system is able to do real-time monitoring of car position, operating velocity curve fault, safety device condition, main board signal and operation.Finally, a test platform composed of detection devices, DSP and computer is built. Port for VB and CAN is designed; serial port configuration program is carried out, which is the base of the test system communication. The main controller program is also done, and the lift well simulation system is built. Overall test of the expert system and the monitoring system is performed. The test results show the applicability of the proposed software and hardware.