Abstract

This study deals with the mathematical modeling, dynamic analysis, hybrid control structure, and experimental tests of a hydraulic servo drive (HSD) flexibly connected by a vibration isolator as a spring damping device (SDD) to a boom manipulator excited by the cyclic impact force generated by a rock breaker. Based on the dynamic model of the HSD-SDD system, the frequency ratios of the rigid and flexible connections to the mass load were determined. The HSD-SDD model was saved as a Hammerstein model with unknown parameters. The dynamic linear part of the HSD-SDD model was adopted as an autoregressive model with an exogenous input (ARX) model. The online proportional integral derivative (PID) controller parameter-tuning algorithm was implemented in several steps. The PID controller tuning process occurs in real time, and the optimal setting of the PID controller depends on the critical ultimate gain and period set at the stability limit. A hybrid control structure consisting of a feedback controller and feedforward controller was proposed. A combination of input shaping and feedforward filters is used, thus the badly damped vibrations are more effectively compensated, resulting in better control accuracy of the HSD-SDD system. The goal of optimizing the hybrid control structure is to determine a feedforward filter coefficient that minimizes the objective function. Finally, the global minimum is calculated from the control error based on the measurement of the input and output signals. The highlight of this study is the development of a new hybrid control structure to compensate for badly damped vibrations.

Highlights

  • The dynamic properties and precision of hydraulic servo drive (HSD) control depend on the rigidity of the mounting of its components: actuators, control elements, load mass, and equipment

  • SIMULATION RESULTS The industrial use of the HSD was considered, in which the cylinder was rigidly mounted on the main boom and the piston rod was flexibly connected via an spring damping device (SDD) to the inner boom of a hydraulic crusher manipulator

  • The purpose of the simulation tests is to assess the dynamic properties of an HSD that is rigidly and flexibly connected to a load mass excited by a cyclic force

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Summary

INTRODUCTION

The dynamic properties and precision of hydraulic servo drive (HSD) control depend on the rigidity of the mounting of its components: actuators (barrel and piston rod), control elements (valves), load mass, and equipment. The dynamic properties of the hydraulic drive change dramatically if part of the moving mass is more or less flexibly connected to the piston rod and/or if the actuator stands on a vibrating base. A single-acting hydraulic actuator connected to a non-rigid base and mass load was considered In this case, using mobile work equipment, a hydraulic actuator is connected to the machine frame, and the machine frame rides on the flexible wheels. Design difficulties arise when selecting an HSD-SDD system for the hydraulic manipulators of an industrial crusher

FORMULATING THE RESEARCH PROBLEM
RIGIDLY CONNECTED LOAD MASS
FLEXIBLE-CONNECTED LOAD MASS The natural frequency fy of the actuator
PULSATION OF PRESSURE IN A SHORT HYDRAULIC LINE
Ch qh dt
SIMULATION RESULTS
THE INITIAL-STATE PARAMETERS
DYNAMIC RESPONSE
EXPERIMENTAL RESULTS
CONCLUSION

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