Smooth braking control of excavator hydraulic load based on command reshaping

Excavators, a type of human-operated construction machinery, suffer from poor hydraulic load braking stability, which seriously affects operator comfort. To address this challenge, this study investigates load braking laws through model analysis and designs an open-loop control algorithm called command reshaping, which can prolong the small-opening time of the main valve by segmentally adjusting the joystick command during load braking and then actively adjusting the key parameters reflecting the system's kinetic-potential energy state, thereby suppressing braking oscillations. The experimental results based on a 1.5-ton excavator indicated that the proposed algorithm can significantly enhance braking stability with a small stop-position deviation, the maximum amplitude of the working pressure of the boom cylinder was reduced by at least 40 %, and the maximum amplitude of the swing motor speed was reduced by at least 54 %. Furthermore, the algorithm is easily implemented, cost-free, and suitable for the performance tuning of excavators.