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Quan Long
Institute of Mechatronics Engineering, Taiyuan University of
Technology,
Taiyuan 030024, China
Neubert T
Helduser Sn
Institute of Fluid Power
and Motion Control,
Dresden University of Technology,
Dresden 01062, Germany
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PRINCIPLE TO CLOSED LOOP
CONTROL DIFFERENTIAL CYLINDER
WITH DOUBLE SPEED VARIABLE
PUMPS AND SINGLE LOOP CONTROL
SIGNAL*
Abstract:
To control the position of differential cylinder closed loop without using any throttle elements, a new idea that two speed variable pumps are used to compensate the non-symmetric flow of differential cylinder is carried out. According to the leaking property of the system, a speed offset principle is also proposed to eliminate the cavitation and tension caused by the leakage and condensation of oil, which makes the system be in the same state as a valve controlled circuit. This principle is explained theoretically and experimentally. Further the relationship that the pressures in cylinder chambers change with load and leakage, and the relationship between biasing speed and pre-load pressures in cylinder chambers are established. The research has proved that the new system has similar technique features as those of controlled with servo valves, but due to the elimination of all the throttle lose the efficiency of system can be improved greatly.
Key words: Electro-hydraulic servo control Speed variable pump Differential cylinder system |