液压挖掘机的半自动控制系统
中英文资料对照外文翻译文献综述
翻译部分
1．英文原文
Semi-automatic control system for hydraulic shovel
Hirokazu Araya),Masayuki Kagoshima
Mechanical Engineering Research Laboratory,Kobe Steel,Ltd.,Nishi-ku,Kobe Hyogo 651 2271,Japan
Accepted 27 June 2000
Abstract
A semi-automatic control system for a hydraulic shovel has been developed.Using this system,unskilled operators can
operate a hydraulic shovel easily and accurately.A mathematical control model of a hydraulic shovel with a controller was
constructed and a control algorithm was developed by simulation.This algorithm was applied to a hydraulic shovel and its
effectiveness was evaluated.High control accuracy and high-stability performance were achieved by feedback plus
feedforward control,nonlinear compensation,state feedback and gain
scheduling according to the attitude.q 2001 Elsevier
Science B.V.All rights reserved.
Keywords: Construction machinery;Hydraulic shovel;Feedforward;State feedback;Operation
1.Introduction
A hydraulic shovel is a construction machinery that can be regarded as a large articulated robot. Diggi
ng and loading operations using this machine require a high level of skill,and cause considerable fatigue even in skilled operators.On the other hand, operators grow older,and the number of skilled operators has thus decreased.The situation calls for hydraulic shovels,which can be operated easily by any person w1 –5x. The reasons why hydraulic shovel requires a high level of skill are as follows.
1.More than two levers must be operated simulta-neously and adjusted well in such operations.
2.The direction of lever operations is different from that of a shovel’s attachment movement. For example,in level crowding by a hydraulic shovel,we must operate three levers ?arm,boom, bucket. simultaneously to move the top of a bucket along a level surface ?Fig.1..In this case,the lever operation indicates the direction of the actuator,but this direction differs from the working direction. If an operator use only one lever and other free-doms are operated automatically,the operation be-comes very
easily.We call this system a semi-auto-matic control system.
When we develop this semi-automatic control system,these two technical problems must be solved.
1.We must use ordinary control valves for auto-
matic control.
2.We must compensate dynamic characteristics of a hydraulic shovel to improve the precision of control.
Fig.1.Level crowding of an excavator and frame model of an excavator. We have developed a control algorithm to solve these technical problems
and confirm the effect of this control algorithm by experiments with actual hydraulic shovels.Using this control algorithm,we have completed a semi-automatic control system for hydraulic shovels.We then report these items.
2.Hydraulic shovel model
To study control algorithms,we have to analyze numerical models of a hydraulic shovel.The hy- draulic shovel,whose boom,arm,and bucket joints are hydraulically driven,is modeled as shown in Fig.
2.The details of the model are described in the following.
2.1.Dynamic model [6]Supposing that each attachment is a solid body, from Lagrange’s equations of motion,the following expressions are obtained:
controller翻译中文
K 3 s m 3 1 g3g;and g s gravitational acceleration. u is the joint angle,t is the supply torque the attachment length,1 g iis the distance between the fulcrum and the center of gravity,m iis the mass of the attachment,I iis the moment of inertia around the center of gravity ?subscripts i s 1–3,mean boom, arm,and bucket,respectively..
2.2.Hydraulic model
Each joint is driven by a hydraulic cylinder whose flow is controlled by a spool valve,as shown in Fig.
3.We can assume the following:
1.The open area of a valve is proportional to the spool displacement.
2.There is no oil leak.
3.No pressure drop occurs when oil flows through
piping.H.Araya,M.Kagoshimar Automation in Construction 10 (2001) 477–486 479
Fig.2.Model of hydraulic shovel.
4.The effective sectional area of the cylinder is the same on both the head and the rod sides. In this problem,for each joint,we have the following