How to control the speed of servo hydraulic press

2026-03-25 19:55:38

The speed of servo Hydraulic Press is controlled by closed-loop control of servo motor speed and hydraulic flow rate. Operation and debugging are mainly completed at three levels: human-machine interface (HMI), servo driver, and hydraulic valve group.

1、 Core speed regulation principle (mainly pump control)

The mainstream modern Servo Hydraulic Press adopts a volumetric speed regulation scheme of servo motor+quantitative pump:

Speed ∝ pump flow ∝ servo motor speed

Pressure ∝ motor output torque (closed-loop control)

No throttling/overflow loss throughout the entire process, high efficiency, low temperature rise

2、 Operational level: Directly set the speed (most commonly used)

On the device touch screen/operation panel, directly set the speed for each stage:

Fast down (fast forward): Set a high speed (such as 80% -100%) to achieve fast movement without load.

Slow working (pressing): Set a low speed (such as 10% -30%) to ensure forming accuracy and smoothness.

Pressure maintenance: The motor runs at low speed/stops, and only leaks are replenished to maintain pressure.

Fast return: Same as fast forward, set high speed.

Most devices support programming for multiple speed curves and automatically switch based on position/time.

3、 Electrical control aspect: parameter optimization (precise speed regulation)

1. Parameters of servo drive

Speed upper/lower limit: Limit the maximum/minimum speed to protect the equipment.

Acceleration and deceleration time: Adjust the smoothness of start/stop to avoid impact.

PID parameters (speed loop):

• P (ratio): Fast or slow response, too large can easily cause oscillation.

• I (integral): Eliminating steady-state errors, excessive response slows down.

• D (Differential): Suppresses overshoot, usually small or turned off.

 Controller/PLC program

Enable speed closed-loop: real-time feedback from displacement/speed sensors, automatically correcting speed.

Set speed ramp: Avoid hydraulic shock caused by step commands.

4、 At the level of hydraulic system: auxiliary speed regulation (valve control/throttling)

Some models retain valve control circuits as a supplement:

Proportional servo valve/flow valve: regulates the flow into the oil cylinder to achieve secondary speed regulation.

Throttle valve/one-way throttle valve: used for fine-tuning, buffering, or limiting maximum speed.

Differential circuit: When fast forward, the two chambers of the oil cylinder are connected to increase the idle speed.

5、 Common problems and debugging points

Unstable speed/crawling: Check PID parameters, sensor signals, hydraulic oil cleanliness, and oil temperature.

Speed cannot reach the set value: Confirm whether the upper limit of motor speed, pump displacement, and system pressure are sufficient.

Strong impact when switching between fast and slow: Extend acceleration and deceleration time, enable smooth transition function.

Load changes affect speed: enable pressure feedback compensation or anti-interference PID.

6、 Operation steps (quick to get started)

Go to Parameter Settings → Speed Parameters on the HMI.

Set the target speed/velocity values for fast forward, work in, and return respectively.

Set acceleration and deceleration time (e.g. 0.5-2s).

Test run, observe stability, fine tune PID and acceleration/deceleration.

Save parameters for mass production.