POSITION CONTROL OF A WATER HYDRAULIC CYLINDER

Abstract

From control point of view there are some serious problems in water hydraulic cylinder drives. Low viscosity of water causes low damping and bad lubrication. Friction is quite high and its behaviour is not very clear. Bulk modulus of water is high and it could cause some problems with short strokes and at the ends of cylinder. The biggest problem is however a lack of good valves. On the market there are some commercial water hydraulic servo and proportional valves, but the specification for them are not very high, especially for proportional valves. In this study experimental tests of the water hydraulic cylinder drive with different valves are presented. The characteristics of different water hydraulic cylinder drives are discussed.