Calibration of Actuators

Calibration of hydraulic actuators:

The hydraulic actuators are used in numerous applications, For example, a typical antilock brake the system in cars can include several hydraulic actuators to control the fluid pressure in the individual components such as a master cylinder and a plurality of wheel cylinders.

These generic tables are created to take into account variations in the worst case scenario, manufacturing variations and system variations. Therefore, the tolerances of the values contained in the tables are relatively large and result in less than optimal performance of the actuators.

Stroke calibration for actuator valve:

To determine the stroke positions 0 and 1 in the valve, calibration is required when the valve and actuator are commissioned for the first time

The calibration procedure can be repeated as often as necessary.

Normally, there is a slot in the printed circuit boards of many actuators. In most cases, to initiate the calibration procedure, the contacts within this slot must have a short circuit, for example, a screwdriver. The calibration can proceed automatically:

  • The actuator operates to the zero stroke position: the valve closes, the green LED flashes;

  • The actuator then runs at 100 strokes position;

  • The measured values are stored;

  • The calibration procedure has finished and the green LED flashes;

  • The actuator now moves to the position defined by the control signal of its controller

Resistance calibration for hydraulic pump:

  1. The pump used to supply study flow of oil to the supply point of a hydraulic Wheatstone bridge labeled as S. The oil flows continuously through the bridge to the return point labeled R and is finally returned to the pumping station. The four variable flow limiters in this bridge are contained in a valve unit.

  2. indicates a pneumatic valve;

4- gives two bellows; 5- is the actuator plate.

The objective of the calibration is that the four nozzles have a nominal flow resistance measured per pascals per second per cubic meter. Before starting calibration, ensure that

  • the resistance of each nozzle is equal

  • the pressure at the two control ports is the same when the electric drive is 0 A.

  • At 0 A drive, the pressure of the control port is half the pressure drop between the supply and the return;

  • The flow through the two sides of the bridge is the same

  • the valves must be all the same

  • for each side of the valve, calibration proceeds independently