• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.4
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• pp.9-15
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• 2009

Hydraulic excavators are the representative of field robot and have been used in various fields of construction. Since the excavator operates in the hazardous working environment, operators of excavator are exposed in harmful environment. Therefore, the hydraulic excavator automation and remote operation system has been investigated to protect from the hazardous working environment. In this paper, remote operation excavator system is developed using the mini hydraulic excavator and the tracking control system of each links of excavator is designed. To apply the tracking control system, the adaptive sliding mode control algorithm is proposed. It is found that the performance of the proposed control system is improved through experimental results of using the remote operation excavator system.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.12
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• pp.82-87
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• 2007

Excavator has been used in wide field since the attachment in the end effect can be changeable according to the purpose of working. However, efficiency of work using excavator mainly depends on an operator's ability. For the purpose of improving the efficiency of work and reducing the fatigue of operator, the automatic excavator system has been researched. In this paper, the tracking control system of each links of excavator is designed before developing the automatic excavator system. In order to apply the tracking control system, the pneumatic excavator system is developed and the tracking control system is applied. For designing the tracking control system, the adaptive sliding mode control algorithm is proposed. The performance of the proposed control system is evaluated through experiments using the pneumatic excavator system.

• The Journal of Korea Robotics Society
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• v.16 no.3
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• pp.232-237
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• 2021

In this research, a real-time tele-operation system for unmanned excavator using the LTE communication system is suggested. The distance between the operator and the excavator is limitless as long as the LTE communication available. The motion and video data of the excavator is synchronized using the Vehicle Control Unit (VCU) and streamed to the operator for immersion feeling. The video is played on the operator's monitor and the motion data is used to regenerate the excavator movement on the developed master platform. In general, a excavator is tele-operated using RF signal and the maximum distance for direct control is limited to within a hundred meter. In this research, the immersion tele-operation system is suggested for excavator operation within an 100ms time delay using the developed master platform, the VCU and LTE communication. A successful test run of the suggested tele-operation system has already been performed between an operator in Songpa (Seoul) and a excavator in Ansan (Gyeonggi-do) which is approximately 35 km apart.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.286-290
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• 2004

This paper deals with tipping over of hydraulic excavator's crane work. If the excavator lifts too heavy weight, the excavator will be tipped up. This is account for 38% of whole excavator accidents. In this paper, tipping-over load which is maximum load of excavator can lift with displacement of excavator links, real load and tipping-over rate are computed with Zero Moment Point theory. ZMP is verified with simulation and experiment.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.209-214
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• 2004

This paper deals with tipping over of hydraulic excavator's crane work. If excavator lift too heavy weight, excavator tipped up. This is 38% of whole excavator accidents. In this paper, tipping over load which is maximum load of excavator can lift with displacement of excavator links, real load and tipping over rate are calculated with Zero Moment Point. We designed the tipping-over stability criterion algorithm considering the dynamic characteristics to which ZMP theory is applied and discussed the usefulness of the proposed algorithm compared with the moment equilibrium equation through the simulation and the actual test.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.642-651
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• 2009

The history of excavator design is not long enough which still causes most of the design considerations to be focused on static analysis or simple functional improvement based on static analysis. However, the real forces experiencing on each component of excavator are highly transient and impulsive. Therefore, the prediction and the evaluation of the movement of the excavator by dynamic load in the early design stage through the dynamic transient analysis of the excavator and ensuring of design technique plays an importance role to reduce development-cost, shorten product-deliver, decrease vehicle-weight and optimize the system design. In this paper, Commercial software DADS and ANSYS help to develop the track model of the crawler type excavator, and to evaluate the performance and the dynamic characteristics of excavator with various simulations. For that reason, the track of crawler type excavator is modelled with DADS Track Vehicle Superelement, and the reaction forces on the track rollers were predicted through the driving simulation. Also, the upper frame and cabin vibration characteristics, at the low RPM idle state, were evaluated with engine rigid body modelling. And flexibility body effects were considered to determine the more accurate joint reaction forces and accelerations under the upper frame swing motion.

• Journal of Drive and Control
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• v.17 no.1
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• pp.37-43
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• 2020

An intelligent excavator can be divided into Machine Guidance (MG), semi-automatic, and unmanned by technology. The MG technology excavator is equipped with a tilt sensor on each link of the excavator and a GPS is installed on the excavator body to inform the user of the position of the excavator bucket end. Machine control (MC) technology that assists the user's work can be divided into semi-automatic and fully automatic technology. The semi-automatic MC equipment has already been commercialized by Komatsu and Caterpillar. The MC excavator is equipped with an electro-hydraulic system, sensors and controllers to control the excavator bucket end according to the user's needs. In this study, the semi-automated excavator modified based on manual excavator, is equipped with an electro-hydraulic system, a controller system, multi-sensors and a control algorithm is developed to assist in excavation work such as leveling and grading. By applying the developed technology, it was possible to confirm productivity improvement compared to manual digging and leveling work. In the future, further research to improve the accuracy of the hydraulic precision control and collaborative work with heterogeneous construction equipment such as dump truck and automated collaboration tasks technology could be developed.

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.3
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• pp.14-19
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• 2006

Recently, the cylinder of the excavator is applied in the various environment. So, we need the development of the simulator for the excavator. The simulator has the effects of the decrease of the cost and improvement of the cylinder's performance. In this paper, we design the simulator for the excavator and makes an analysis of the dynamics and structure. The simulator was applied to the excavator's models of 10ton, 20ton and 30ton because we built the data base of a real excavator's cylinder of information in the experiment. And we used the FEM analysis for the comparative study on the characteristics.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.151-155
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• 1996

To automate an excavator the control issues resulting from environmental uncertainties must be solved. In particular the interactions between the excavation tool and the excavation environment are dynamic, unstructured and complex. In addition, operating modes of an excavator depend on working conditions, which makes it difficult to derive the exact mathematical model of excavator. Even after the exact mathematical model is established, it is difficult to design of a controller because the system equations are highly nonlinear and the state variable are coupled. The objective of this study is to design a multi-layer neural network which controls the position of excavator's attachment. In this paper, a dynamic controller has been developed based on an error back-propagation(BP) neural network. Computer simulation results demonstrate such powerful characteristics of the proposed controller as adaptation to changing environment, robustness to disturbance and performance improvement with the on-line learning in the position control of excavator attachment.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.3
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• pp.29-41
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• 1992

According to the recent increase of demands for multi-function and economics on hydraulic excavator, it is required that excavator should have simple operation, higher and operational efficiency, however the modeling of engine/pump system of excavator is not prescribed by the paper. So, in this paper the modeling of engine/pump system of excavator is suggested by identification method from step response and verified effectiveness of identification system by comparing with experimental results which was conducted using PID controller. To improve the problem of parameter variation and modeling error in the system, sliding mode control was introduced and new switching surface was designed. This control algorithm was applied to a hydraulic excavator by simulation, and its effectiveness was verified, and the results of variable structure system for the excavator system using a output component was compared with that of full state feedback when load disturbances and system paramenter variation exist.