| 摘要 |
<p>A hydrostatic or pneumatic drive for driving a mass to be accelerated and decelerated, such as in a die casting or injection moulding machine, has a controllable valve arrangement which is operable to vary the fluid flow rate therethrough. The fluid flow rate is controlled by a reference value control generator operable to produce a ramp having superimposed thereon further control pulses. Such control pulses are a positive control pulse at the beginning of the rising slope and at the end of the falling slope of the ramp and a negative control pulse at the end of the rising slope and at the beginning of the falling slope of the ramp. Each control pulse has a volume which corresponds to a so-called compression volume factor which reflects the compressibility of the fluid used in the drive and also of the elasticity of ducts which expand by fluid pressure.</p> |
