The hydraulic system of the muscle module is powered with a 540 type , brushless motor. This type of the motor provides full control of torque and speed but require a dedicated controller.

The controller was build  using MC33035 Brushless DC Motor Controller IC. The outputs of the chip are used to drive the high current MOSFET's  with the help of the MIC4427 driver IC's. The current control loop is realized with the feedback resistor etched directly on the PCB.  The complete schematic of the controller , as well as the GERBER files of the PCB can be found in the files section.

Filling the system , and bleeding the air of it is done with the tank installed above the muscles and pump and two service connectors for the schrader valves ( the type used for air conditioning repair ) .

The filling procedure:

     - connect the service valves to the schrader valves

     - open  the valves and let the gravity fill the system with fluid

     - start the pump and let it bleed the air.

     - close the outlet valve and let the pump fill the muscle to its maximal capacity

     - close the inlet valve and turn off the pump .

     - disconnect the service valves and secure the schrader valves with caps.

This way both muscles are filled and have a positive pressure in the idle state.