Modelling of an hydraulic excavator using simplified refined instrumental variable （SRIV） algorithm

Instead of establishing mathematical hydraulic system models from physical laws usually done with the problems of complex modelling processes, low reliability and practicality caused by large uncertainties, a novel modelling method for a highly nonlinear system of a hydraulic excavator is presented. Based on the data collected in the excavator＇s arms driving experiments, a data-based excavator dynamic model using Simplified Refined Instrumental Variable （SRIV） identification and estimation algorithms is established. The validity of the proposed data-based model is indirectly demonstrated by the performance of computer simulation and the.real machine motion control exoeriments.     

基于AMESim的液压挖掘机正流量系统的仿真研究

以小型液压挖掘机为仿真样本,分析了液压挖掘机的正流量系统的工作原理,根据实际的液压元件参数,利用AMESim软件的HCD液压元件库,构建多路换向阀和正流量泵的模型及挖掘机液压系统仿真模型,并对其仿真结果进行分析。对比了定量泵系统和正流量系统的流量损失,验证了正流量系统的节能性,证明建立的仿真模型的有效性。     

Gray box modeling of an excavator’s variable displacement hydraulic pump for fast simulation of excavation cycles

This paper describes the results of a study focused on the application of gray box modeling methodology on an excavator's hydraulic pump. This modeling approach has been adapted to accelerate the control system development time for a complete excavator, while providing accurate system dynamics. This mathematical model has been developed using the bond graph methodology. The excavator is described by two models: a hydraulic model and a kinematic model; dynamic parameters are continuously calculated during an excavation cycle, providing a platform to study the pump's behavior. The gray box model of the variable displacement pump has been validated on the basis of a set of experimental data collected on a test rig and on the field using an excavator. Herewith the results of this study are presented.     

挖掘机轨迹跟踪的滑模变结构控制

对液压挖掘机工作装置的轨迹跟踪进行了研究。在分析了液压挖掘机工作装置的动力学方程的基础上,针对其复杂的非线性,提出了一种新的液压挖掘机工作装置轨迹跟踪方法,即应用机器人学理论,建立了三自由度液压挖掘机工作装置的拉格朗日动力学模型,设计了带低通滤波器的滑模控制器,利用低通滤波器的滤除高频信号的功能,消除控制信号的抖动,给出沿规划轨迹工作所需的控制量,并给出了控制系统的设计方法。对三自由度工作装置进行了仿真研究,其结果表明,所设计的控制器对设定轨迹的跟踪具有良好的动态特性,对系统的不确定性具有较强的鲁棒性,在存在模型误差和外部扰动的情况下,该方案既能达到高精度快速跟踪的目的,又能消除滑模控制的抖动问题。     

A Robust Control Approach for Hydraulic Excavators Using <Emphasis Type="Italic">μ</Emphasis>-synthesis

In this work, a robust control is applied to the automation of a hydraulic excavator. Hydraulic excavators exhibit complex nonlinear behavior due to the inherent nonlinearity of the hydraulic servo system. Furthermore, the hydraulic excavator is subject to large disturbance forces during interaction with the environment. As a result, conventional feedback control techniques, such as a proportional-integral-derivative (PID) control, fail to provide consistent performance over the whole operation region of the excavator. Especially, when phase-offset errors vary between joints, undesirable motions are generated in the workspace, which evidently degrades the overall performance of the controller. With this in mind, we apply a robust control approach to the autonomous hydraulic excavators. By handling the nonlinearities and disturbances as uncertainties within the joint dynamics, a robust controller is designed by means of μ-synthesis that guarantees robust stability and performance within the given uncertainty bounds. Furthermore, by adopting a common model reference for each joint, we seek to increase the overall performance of tracking the digging trajectory in the workspace. Experimental results of the robust controller conducted on an industrial 21-ton class hydraulic excavator are presented.     

基于CAN总线的液压挖掘机轨迹规划系统的研究

介绍了基于CAN总线的液压挖掘机轨迹规划系统,该系统是一个上下位机结构,下位机采用MTC控制器作为硬件平台;采用CAN总线作为MTC与上位机的数据传输通道,很好地满足系统的传输要求.为了实现挖掘自动化,提出了液压挖掘机工作装置运动控制的步骤和方法.为液压挖掘机的自动控制提供了方法和依据.     

故障预测与健康管理系统建模技术研究

简要介绍了PHM系统建模的主要方法,并依据飞机特征,给出飞机PHM系统分层体系模型,提出了基于数据的飞机典型部件液压泵PHM系统的建模方法,通过试验对该方法进行了验证.     

Modelling and remote control of an excavator

This paper presents the results of an on-going project and investigates modelling and remote control issues of an industry excavator. The details of modelling, communication, and control of a remotely controllable excavator are studied. The paper mainly focuses on trajectory tracking control of the excavator base and robust control of the excavator arm. These will provide the fundamental base for our next research step. In addition, extensive simulation results for trajectory tracking of the excavator base and robust control of the excavator arm are given. Finally, conclusions and further work have been identified.     

机器人液压挖掘机运动系统的建模与控制

首先利用机器人运动学将铲斗的理想运动轨迹和各工作装置的目标转角序列联系起来,然后利用拉格朗日方程建立各工作装置的运动学模型,最后推导出LUDV液压驱动系统的电液模型,从而得到了挖掘机器人运动系统的完整模型．针对系统动力学的高非线性、参数的不确定性、外界干扰及比例方向阀的死区及非线性增益等特点,提出一种建立在自适应鲁棒控制基础上的非连续映射方法来处理运动系统并利用鲁棒反馈来消除近似误差．最后利用动臂控制试验来验证控制方法的正确性．     

液压挖掘机工作装置姿态检测

通过对倾角传感器工作原理的分析及液压挖掘机工作装置运动的研究,阐述了怎样利用双轴倾角传感器完成对液压挖掘机工作装置的姿态定位问题,为实现液压挖掘机的智能化提供了前提条件。     

Comprehensive theoretical digging performance analysis for hydraulic excavator using convex polytope method

This paper proposes a method for analyzing comprehensive theoretical digging performance of an excavator based on the convex polytope. The convex polytope is generated by using Newton–Euler’s equations to establish dynamic relationships between the digging capability of the bucket and the driving capability of hydraulic cylinders with the consideration of the excavator tipping and slipping constraints, and is used to identify the excavator’s output capability for digging forces and moments in the bucket force space. A set of indices for theoretically quantifying the digging capability, digging efficiency, as well as the matchability between the manipulator mechanism and the driving capability of hydraulic cylinders are proposed based on the polytope, and they are used to assess the digging trajectory characteristics and the dynamic digging performance of the entire excavator workspace. Two case studies for the excavator’s digging performance assessment and optimal digging trajectory generation are conducted to test and validate this method. The proposed method contributes to comprehensively and deeply understand the design principles of an excavator, and shows the promising application prospect for guiding the design and development of new excavators.

     

新型混合动力挖掘机动臂势能回收系统研究

针对目前混合动力液压挖掘机工作装置势能有效回收的难题,设计了一种采用蓄能器与液压马达的新型动臂势能回收系统。以某小型挖掘机为研究对象,在AMESim环境中建立液压系统模型,基于PID经典控制的电机恒转速控制策略,通过Adams与AMESim联合仿真动臂下放时的变负载工况,得出整个系统的势能回收率。理论分析与仿真结果表明,势能回收系统可以有效回收动臂下放时的势能,并且具有动态响应快、电机的发电效率高的特点,大大提高了系统的势能回收率。     

Control of a heavy-duty robotic excavator using time delay control with integral sliding surface

The control of a robotic excavator is difficult from the standpoint of the following problems: parameter variations in mechanical structures, various nonlinearities in hydraulic actuators and disturbance due to the contact with the ground. In addition, the more the size of robotic excavators increase, the more the length and mass of excavator's links; the more the parameters of a heavy-duty excavator vary. A time-delay control with switching action (TDCSA) using an integral sliding surface is proposed in this paper for the control of a 21-ton robotic excavator. Through analysis and experiments, we show that using an integral sliding surface for the switching action of TDCSA is better than using a PD-type sliding surface. The proposed controller is applied to straight-line motions of a 21-ton robotic excavator with a speed level at which skillful operators work. Experiments, which were designed for surfaces with various inclinations and over broad ranges of joint motions, show that the proposed controller exhibits good performance.     

On the modelling of actuator dynamics and the computation of prescribed trajectories

The dynamics of actuator mechanisms is presented using a multibody modelling approach to concisely express the structure of the system equations. The Lagrange equations are used to obtain the Newton–Euler equations to which constraint equations are augmented to form a system of differential algebraic equations. The differential algebraic equations are cast as ordinary differential equations and computed using the numerical integrator LSODAR of Petzold and Hindmarsh. Constraint compliance is investigated to ensure the accuracy of the results. Animation of an excavator and wheel loader system is presented and graphs of constraint forces show the nature of the actuator dynamics involved in maintaining specified bucket trajectories. The model is general in nature and caters for arbitrary mechanism connectivity and physical properties.     

Design of a Networked Tracking Control System With a Data-based Approach

Tracking control is a very challenging problem in the networked control system (NCS), especially for the process with blurred mechanism and where only input-output data are available. This paper has proposed a data-based design approach for the networked tracking control system (NTCS). The method utilizes the input-output data of the controlled process to establish a predictive model with the help of fuzzy cluster modelling (FCM) technology. Then, the deduced error and error change in the future are treated as inputs of a fuzzy sliding mode controller (FSMC) to obtain a string of future control actions. These candidate control actions in the controller side are delivered to the plant side. Thus, the network induced time delays are compensated by selecting appropriate control action. Simulation outputs prove the validity of the proposed method.      

栅格数据地理信息系统(Raster GIS)关键技术分析

数据是地理信息系统的基础,强大的地理信息分析功能对地图数据有很高的要求.国内外大多数应用型地理信息系统都是基于矢量地图数据格式的.这样的系统在提供便利操作的同时,增加了系统开发成本和开发周期.如果建立基于栅格数据的地理信息系统,不需要数字化编辑处理地图数据,节省了矢量化数据的成本,并且地图显示更为形象、直观.在分析栅格数据和矢量数据的基础上,探讨了基于栅格数据的地理信息系统体系框架,并就基于栅格数据的地理信息系统开发中的基本地图操作、属性查询、地图分析等关键技术进行研究,提出了一些思路和解决办法.同时,将该技术成功应用到军事演习系统中,取得了良好的效果.     

基于激光雷达的挖掘机器人回转避障研究

针对挖掘机器人在回转过程中易发生事故的现象,提出了工作装置回转避障方法.通过分析挖掘机器人工作装置的运动特性,结合运动学建立了挖掘机器人的运动学模型.利用安装在挖掘机器人两侧的激光雷达对作业环境进行识别,根据识别的障碍物求解可行域,并通过避障算法控制挖掘机器人避开障碍物.实验结果表明:挖掘机器人能安全避开障碍物,证明了方法的可行性.     

挖掘机器人仿真模型及其驱动引擎的设计

以挖掘机器人为例,研究了仿真模型的建立手段及其驱动方法,提出并实现了一种模型快速建立方法和能通用于同类机械的驱动引擎的设计方法,在此基础上设计了一个完备的挖掘机仿真显示类,通过对本类的继承,应用程序具备各种液压挖掘机的三维仿真驱动和显示功能。