| Displacement controlled hydraulic actuation has proven to be an efficient alternative to valve controlled hydraulic actuation. Previous work has concentrated on the development of these circuits for proof of concept prototype machines in order to demonstrate improved fuel efficiency. In this work, the displacement controlled technology has been developed further and applied to a prototype miniature excavator. Electronic sensing and control, including CAN capable electronic control units and joysticks was implemented on the prototype machine. Electronic control concepts such as electronic cylinder cushioning, anti-stall control, relief flow reduction, blade float, and inactive circuit pressure reduction were developed in order to improve operator feel, machine efficiency, and to demonstrate the advantages of electronic control. These concepts were first developed in simulation and then implemented on the prototype machine and tested by experienced operators. |
