Smith Predictor Utilization to Improve a Leveling Operation Accuracy for Hydraulic Excavator

Abstract

Performances of main components such as an engine, hydraulic pump, cylinder, valve and so on for a hydraulic excavator have been improved year by year. The system also related with a controller to assist operations have been complex more and more. An excavator is a general construction machine for a civil engineering and performs a various of applications such as a digging, truck loading, lifting and leveling. A powerful digging force and fast motions are required. Besides, very sensitive and accurate operations are needed. There is a response delay of the hydraulic system from an operator input command to a hydraulic cylinder motion as an actuator. When an assist controller to manipulate the bucket is developed, the delay should be considered in order to improve the accuracy. In this paper, we investigate to utilize Smith Predictor for a leveling operation which is required high accuracy as a system with time delay. It's confirmed that Smith Predictor is better than a conventional PID controller to quantitatively compare the following trajectories of the bucket tip to a target.