COMPUTATIONAL FLOW RATE FEEDBACK AND CONTROL METHOD IN HYDRAULIC ELEVATORS

The computational flow rate feedback and control method,which can be used in proportional valve controlled hydraulic elevators,is discussed and analyzed.In a hydraulic elevator with this method,microprocessor receives pressure information from the pressure transducers and computes the flow rate through the proportional valve based on pressure-flow conversion real time algorithm.This hydraulic elevator is of lower cost and energy consumption than the conventional closed loop control hydraulic elevator whose flow rate is measured by a flow meter.Experiments are carried out on a test rig which could simulate the load of hydraulic elevator.According to the experiment results,the means to modify the pressure-flow conversion algorithm are pointed out.