Non standard robotic arm hydraulic station complete equipment

Is there any variable in the complete set of non-standard robotic arm hydraulic station equipment/radial piston pump?
Not many, so far I haven't seen them. There are many radial blade variable displacement pump channels, and the main adjustment method is to adjust the eccentricity of the shaft. Axial adjustment adjusts the inclination angle of the inclined plate, while radial adjustment adjusts the eccentricity of the shaft.
What is the difference between a variable displacement pump and a quantitative pump?
1. Adjust the output flow rate of the pump according to the required load speed; 2. Adjust the output pressure of the pump according to the load size requirements
How many control methods are there for the variable mechanism of a plunger pump?
There are various types of variables, such as manual variables, hydraulic control variables, manual follow-up variables, electric follow-up variables, as well as constant pressure, constant current, constant power variables and other formal variables!
I have seen that there is a connecting circuit (definitely not a solenoid valve) on the motor housing of both quantitative and variable axial piston motors, similar to a sensor. May I ask what this is?
The measurement is the system pressure, usually a pressure relay, which provides protection for the system! Non standard robotic arm hydraulic station complete equipment