Journal Article

Research on precision control strategy of electro-hydraulic proportional system for shotcrete robotic arm based on PID-MPC

Zhang, Peng, Zhang, Zhaoyun, Tian, Dan, Du, Mingchao, Zhang, Kun, Tian, Shengli, Liu, Xinfeng, Meng, Xianwei, Zhang, Heng, Ma, Bin

2025

Overview

This study addresses the common issues of slow dynamic response and significant hysteresis in nonlinear electro-hydraulic systems, with a particular focus on optimizing the control performance of shotcrete robots operating under complex working conditions. The electro-hydraulic proportional control system was first designed and mathematically modeled. Based on input–output data collected under actual operating conditions of the shotcrete manipulator, signal preprocessing was performed using a wavelet soft-threshold denoising algorithm. Subsequently, system parameters were identified using a particle swarm optimization (PSO) algorithm enhanced by least squares estimation, resulting in a high-accuracy system transfer function. To overcome the limited robustness of traditional PID controllers under strong nonlinearities, as well as the real-time computational burden of standalone model predictive control (MPC), a dual-loop control strategy was proposed—employing PID feedback as the inner loop and MPC as the outer loop—to optimize and simulate the electro-hydraulic system. Experimental validation was conducted on a six-degree-of-freedom shotcrete robot platform through extension and rotational motion control tests of the robotic boom. Results show that, compared to conventional PID control, the proposed PID–MPC approach significantly improved system responsiveness and tracking accuracy. Specifically, in the extension test, the maximum tracking error decreased from 0.13 m/ s to 0.04 m/s, and the maximum settling time was reduced from 3.0 s to 0.45 s; in the rotational test, the maximum tracking error dropped from 8°/s to 4 ° /s, and the maximum settling time shortened from 2.6 s to 0.8 s. This study offers a practical and effective solution for accurate modeling and high-performance control of complex electro-hydraulic systems, providing a solid theoretical foundation for the development and engineering application of intelligent and efficient shotcrete equipment.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 639/166/986 / 639/166/987 / 639/166/988 / Accuracy / Algorithms / Control systems / Controllers / Electro-hydraulic proportional system / Expected values / Humanities and Social Sciences / Hydraulic equipment / Hydraulics / Load / Mathematical models / Mathematics / Model predictive / Model predictive control (MPC) / multidisciplinary / Optimization / Parameter identification / PID control / Robotics / Robots / Science / Science (multidisciplinary) / Shotcrete robot / Working conditions