Synchronous control of hydraulic cylinders for tunneling machine based on improved ESO

The hydraulic system of the tunneling machine exhibits significant nonlinearity, resulting in increased data measurement costs and reduced the synchronization accuracy of two hydraulic cylinders. The crucial part of the tunneling machine is the cutting mechanism for coal mining, with its hydraulic system primarily comprising the lifting hydraulic system and the rotary hydraulic system. However, the synchronization precision of two hydraulic cylinders greatly impacts the reliability of the lifting and rotary circuits. To reduce data acquisition costs during the operation of the tunneling machine and achieve high synchronization accuracy between hydraulic cylinders, a control method based on an improved extended state observer active disturbance rejection control (ESO-ADRC) is proposed. First, a mathematical model of the valve-controlled hydraulic synchronization system is established, and introduce dead zone compensation in the electro-hydraulic proportional directional valve to improve the response speed of the control system by 0.5–1 sec. Then, improved and traditional extended state observers are integrated into the active disturbance rejection controller. Result indicated that the improved ESO-ADRC system offers better observer tracking speed performance, using displacement and velocity as control objectives, the maximum synchronization error was reduced by 35 and 50%, respectively. Additionally, master–slave control and deviation coupling control methods are applied to the system. The results show that with displacement and velocity as control objectives, the maximum absolute value synchronization error of the hydraulic cylinders in the deviation coupling active disturbance rejection control system was reduced by 66 and 63%, respectively.