Feasibility Study of Using a Coupler Skate Encoder System for Monitoring the Real Time Status of Lift Door Operation

This work presents a proof-of-concept study of the encoder system developed for monitoring the health of coupler skate assembly used in automatic door header system of lifts. The motivation of developing a coupler skate encoder system is to provide real-time information on coupler skate status and its performance which could be further used for developing a preventive maintenance program of door header system. The coupler skate encoder system consists of a Hall effect-based sensor, microcontroller board, and power supply unit. The Hall effect sensor measures the real-time angular rotation of coupler skate assembly. The microcontroller is flashed with the firmware which evaluates the time series data, and as a result, it sends a digital signal in case of any deviation in expected performance of coupler skate assembly. A benchtop sensor calibration set up is constructed to prepare a look-up table for calibrating analog voltage signal against angle in degrees. The coupler skate encoder system is tested on automatic lift door test jig for evaluating its various parameters like accuracy and repeatability of sensor and real-time data analysis by the microcontroller. The results obtained from the experiments are found to be encouraging such that the coupler skate encoder system resolves the smallest angular rotation which is required to detect an erroneous condition of coupler skate assembly operation. The proof of concept study highlighted in this document introduces a new concept of real-time monitoring of sub-assembly of door header system, which could be a guiding document in developing preventive maintenance technologies specially designed for lift automatic doors. The preventive maintenance technologies of such kind as discussed in this paper would be a significant development for smooth and error-free operations of lift doors.