Research on a new type of flow control system of hydraulic elevators with car speed feedback

This paper introduces an innovation design of flow control system for hydraulic elevators with car speed feedback. By measuring pulse signal emitted by photoelectric encoder mounted on the elevator car, a single-chip computer controls the electrohydraulic proportional integrated flow valve, then drives the elevator car by a hydraulic cylinder. With this set of single-chip computer control system, good speed performance of the elevator can be achieved. Furthermore, it has strong robustness against the disturbance of oil temperature variation, mechanical friction and other disturbance factors. In order to obtain better ride comfort and soft start of the elevator, PID control algorithm is also proposed. Some mathematical models both for static and dynamic states have been established, consequently simulation results are found to be in close agreement with the experimental results.