Analysis of Signals and Power Flow in a Digital Hydraulic Multi Actuator Aplication

A combination of digital hydraulic four notch control valves and the digital hydraulic power management system (the DHPMS) has many controller levels, both parallel and series. The DHPMS is a multi-port sink/source of hydraulic power. Digital hydraulic valves are used to control the actuators. Both the DHPMS and the digital valves are based on the idea that all complexity is in the software and the hardware is based on arrays of mechanically simple base units. Controllers work together merging into a power flow system where the whole power transfer line is controlled from a single pumping piston within the pump to the movement of the tip of the boom. Or vice versa, if the operating conditions allow negative power to be routed backwards. In the paper certain measurements are looked into; second by second and a signal by a signal. The paper presents and verifies functionality of the novel combination of technologies. How signals flow in the controllers and how they actually control the power flow in the system is explained. The test system is a two-actuator boom, and as two is the smallest example of multi, the controller is designed by a simple and robust control method.