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

Abstract

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.

Energy Balance of Electro-Hydraulic Powertrain in a Micro Excavator

“…The original diesel engine powered system was otherwise similar, but the proportional directional control valves were manually controlled. For description of the excavator modification, refer to [1][2][3]. The current conventional hydraulic system of the studied excavator is presented in Figure 1.…”

“…The studied excavator has originally been diesel engine powered producing 13.6 kW at 2200 rpm, but it has been modified to electric motor powered [1][2][3]. The excavator has also been equipped with sensors throughout the electrohydraulic powertrain in such a way that the overall energy balance and the power consumption of individual components and work movements can be estimated in detail.…”