Research On Positive Energy-saving Control System With Synthetic Pilot Pressure Of Excavator

Hydraulic excavator is a kind of widely used construction equipment. In days ofenergy crisis and environment-friendly, energy saving of excavator is urgent and ofhigher development potential project.Positive flow control system of excavator controls the pilot pressure with pilotcontrol handle, then the pilot pressure controls multi-way valve’s opening and thehydraulic pump variable mechanism at the same time, it can achieve the purpose ofregulating the flow of the working devices and the displacement of the pump separately.Positive flow control can overcome the problems of the negative flow control systemsuch as more intermediate links, longer response time and lower system flow matchaccuracy. In order to control the displacement of the pump, the traditional positive flowcontrol system selects the highest pressure from the pilot pressure which controlsdifferent actuators by shuttle valves. But it can’t synthetically and accurately control thedisplacement of the pump according to the pilot pressure of each actuator, this resultsthe system lower power efficiency and higher energy loss. In addition, using a series ofshuttle value will lead to an intricate system. In order to solve the problem, this paperputs forward a new structure, positive flow control system with synthetic pilot pressure,which controls the displacement of the pump by five parallel connected controlcylinders that were controlled by five pilot pressures. Instead of comparing the pilotpressure by shuttle valves, the new variable control mechanism can synthetically controlthe displacement of the pump according to the flows which were needed by bucketcylinder, arm cylinder, boom cylinder, travel motor and rotary motor.The hydraulic model based on AMESim was established. The dynamic simulation ofthis new type model was done, and was compared with conventional positive controlsystem. The results of the simulation show that the precision of the matched flow andthe power efficiency is higher in the positive control system with synthetic pilotpressure than in the conventional positive control system.