Parameter Identification and Control Algorithm of Electrohydraulic Servo System for Robotic Excavator Based on Improved Hammerstein Model

Abstract

In view of the nonlinearity and time-varying characteristics of the electrohydraulic servo system of the robotic excavator, a nonlinear adaptive identification and control algorithm based on improved Hammerstein model is proposed. The Hammerstein algorithm model can approximate the nonlinear system with enough precision, but for the time-varying systems is not satisfactory. In order to compensate for the influence of time-varying factors, the fuzzy control module is designed to adaptively update the forgetting factor. The experimental results show that the improved Hammerstein model error is about 40.11% less than the classical Hammerstein model error. This proves that the improved Hammerstein model is feasible and effective to describe the electrohydraulic servo system of the robotic excavator.

A Case Study of a Hydraulic Servo Drive Flexibly Connected to a Boom Manipulator Excited by the Cyclic Impact Force Generated by a Hydraulic Rock Breaker

“…The HSD-SDD model (36) was saved as the Hammerstein model with unknown parameters consisting of two parts: a static nonlinear part and a dynamic linear part, and u(k), x(k), (k), and y(k) are the identification input, intermediate state, noise sequence, and the output of the system [26,27]. The static nonlinear subsystem is approximated by the set polynomial degree and is described by the nonlinear function of the nth order that binds the nonlinear output x(k) to the input u(k):…”

Energy Efficiency and Limitations of the Methods of Controlling the Hydraulic Cylinder Piston Rod under Various Load Conditions

“…In Jinxing et al [57], based on the example of an automated excavator, a parameter identification and control algorithm based on the Hammerstein model was developed. This model was improved to be useful for the time-varying system-modifications including the possibility of adaptive updating of the forgetting coefficient.…”