Open-loop Independent Metering Control of a Multi-DOF Forwarder Boom

This study applies independent metering control in a forestry forwarder in order to improve its energy efficiency. The paper describes the control method, which enables smooth control mode switches and relatively accurate velocity tracking without position, velocity or acceleration feedback. The energy saving capability is analysed through measured, realistic, working cycle, which is repeated for the baseline system and independent metering system. The input energy taken by the control valves is compared. Furthermore, the power losses of the supply pump and diesel engine are modelled to achieve semi-empirical estimate for the diesel fuel consumption. The results show an average reduction of 25% in the fuel consumption when compared to the baseline.