Performance regulation of pneumatic actuator and hydraulic actuator

The compressibility of gas and hydraulic oil is small, so the hydraulic transmission works smoothly, the reversing impact is small, it is easy to realize rapid start, braking and frequent reversing, and the operation and control are convenient, and a wide range of stepless speed regulation can be realized, and the automatic control of large load, high precision and complex movement can be realized.

Generally, mineral oil is used as the working medium, and the relative moving surface can be lubricated by itself, and the service life is long.

Because the air is compressible, the stability of the pneumatic transmission system is poor, which has a great impact on the accuracy of position control and speed control, so the characteristics of the positioning signal of the pneumatic actuator usually produce a resolution of about 3~5% execution error, which leads to the inaccurate positioning of the valve, the valve is not closed, and the execution error caused by the resolution cannot be located. The position feedback of the positioner constantly corrects the position, resulting in oscillations or loss of control of the entire control loop. In addition, because the working medium air itself is not lubricated, it is necessary to set up an oil lubrication device in the gas path.