Research on the Characteristics of an Electro-Mechanical Direct Drive System for Heavy-Duty Manipulators

Abstract

Heavy-duty manipulators are generally driven by hydraulic systems. The control valves in these systems cause substantial throttling losses, resulting in low overall system energy efficiency. To address this problem, this study proposes an electro-mechanical direct drive system (EMDDS) based on an electro-mechanical actuator (EMA) for energy-efficient actuation of heavy-duty manipulators. A supercapacitor energy-management strategy combining current feedforward with voltage feedback is also developed to recover and reuse the gravitational potential energy of the manipulator efficiently. System parameters were selected for the boom of a 6 t excavator, after which a multidisciplinary co-simulation model was established and an experimental prototype was built for validation. The simulation and experimental results show that the proposed system incurs no throttling loss during operation and achieves high drive efficiency. The system recovers and reuses gravitational potential energy with an efficiency of up to 46.4%. Compared with the load-sensing (LS) system, the EMDDS reduces energy consumption over one boom raising and lowering cycle from 42.25 kJ to 16.86 kJ, a reduction of 60.1%. The analysis and experiments provide a basis for developing energy-efficient electric drives and potential-energy recovery technologies for heavy-duty manipulators.