energy recovery and position control of a hybrid hydraulic excavator

What is it about?

To reduce energy consumption in hydraulic excavators subjected to heavy loads, exploiting the potential gravitational energy (GPE) is a promising approach. In this projected system, GPE is stored as pressure energy in a hydro-pneumatic accumulator. During the initial duty cycle, the boom's upward movement is facilitated by the prime mover. Subsequently, in subsequent duty cycles, the stored pressurized energy, in combination with the prime mover's energy, is utilized to execute the upward boom movement. The position control of the boom cylinder is achieved through a conventional PID controller using a proportional flow control valve (PFCV) and the accumulator.

Featured Image

Photo by American Public Power Association on Unsplash

Photo by American Public Power Association on Unsplash

Why is it important?

This article focuses on the potential energy recovery and position control in a proposed hybrid system. The system includes a hydro-pneumatic accumulator, a driving pump, a hydro-motor, and a loading pump. The proposed configuration surpasses conventional designs by effectively utilizing the unutilized potential energy through the hydro-pneumatic accumulator. Position control of the boom is achieved with reasonable accuracy using a PID controller with the accumulator as the power source and a proportional flow control valve as the control element. The close agreement between simulation and experimental results validates the control strategy. In contrast, the conventional design uses a proportional directional control valve and main pump, resulting in energy losses due to bypassing excess flow. The hydro-pneumatic accumulator eliminates this issue, enhancing energy efficiency by 10% compared to traditional systems.

Perspectives