• International Journal of Control, Automation, and Systems
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• v.1 no.4
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• pp.484-494
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• 2003

In this paper, we describe a hydraulic system design and vehicle dynamic modeling for development of tire roller traction, an essential aspect in the system analysis of tire rollers. Generally, tire rollers are one of the most useful types of machines employed in road construction, technically applied to many construction fields. We also conceptualize a new hydraulic and driving system as well as define the motion equations for dynamic and hydraulic analysis. First, we design the hydraulic circuit of the steering control and driving machine system, which can be employed to advance the performance of the lateral control, creating a prototype of construction equipment. Second, we formulate the hydraulic steering system model and hydraulic driving system model through tire roller system development technology. Finally, we validate the acquired performance results in actual tire roller equipment using the data acquisition system. These results may perhaps facilitate the establishment of priorities and design strategies for incremental introduction of tire roller technology into the vehicle and construction field.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1736-1740
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• 2003

POSCO Kwang-Yang Works #2 Cold Rolling Mill RCL has the main hydraulic system that controlled on/off control method. In the aspect of the consumption of electrical energy this system has some problem. So, we present a continuous control method instead of on/off control method that controls the pressure of main hydraulic system with saving the electric energy.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.67.4-67
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• 2001

In order to push or pull a heavy weight structure, the positions of multiple hydraulic cylinders participated on must be tuned sumultaneously. To do this, it is necessary to control the position of each hydraulic cylinder through mutual tuning controller. In this paper, a tuning control of multiple hydraulic cylinders is introduced under the assumption that each position controller for each cylinder is used.

• Journal of Mechanical Science and Technology
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• v.17 no.7
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• pp.999-1010
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• 2003

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today's highly information-oriented society and increasing demand of electric utilities. This maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulators because hydraulic manipulators have the advantage of electric insulation and power/mass density. Meanwhile an electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the autonomous assembly tasks using hydraulic manipulators. In this paper, the robust force control of a 6-link electro-hydraulic manipulator system used in the real maintenance task of active electric lines is examined in detail. A nominal model for the system is obtained from experimental frequency responses of the system, and the deviation of the manipulator system from the nominal model is derived by a multiplicative uncertainty. Robust disturbance observers for force control are designed using this information in an H$\_$$\infty$/ framework, and implemented on the two different setups. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved even if the stiffness of environment and the shape of wall change.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.80-88
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• 2010

In a conventional system, hydraulic unit pumps out pressurized oil when the power use is not even necessary. As a result, it causes much power loss. This study is on the proposal of new hydraulic unit which controls the revolution of the pump in order to produce proper power needed and to have good response characteristic. In addition, the existing control methods such as PID control method, fuzzy control method, and adaptive control method are applied to the proposed hydraulic unit. Then the best control method is selected and the controller is developed to realize minimum power loss.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.169.1-169
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• 2001

In general, for high performance pressure control system, hydraulic system with electo hydraulic servo valve controls flow rate, it contains many nonlinear term like square-root and change of bulk modulus by flow rate. But, DDV(Direct Drive Valve) contains pressure control loop itself, then it can eliminate nonlinearity and achieve linearity for hydraulic system. In this paper, parameter identification method which uses input and ouput data is applied to obtain DDV's mathematical model and parameter assuming that dynamic characteristic of DDV is first order system. Then, the state feedback controller was designed to implement the force control of hydraulic system , and the control performance was evaluated.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.621-626
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• 2000

Reduction in pressure transients may be important in the hydraulic system and necessary to avoid failure and to improve the efficiency of operation. This study addresses the design and use of an orifice to provide the desired control of the hydraulic actuator system. The experimental apparatus is a model of an automobile shift system. Control is accomplished by installing four different diameter ratio of orifices at appropriate locations in the system. Experimental results show that the orifice can be used to obtain the control of shock and the control level depends on the orifice size, orifice type, operating conditions.

• Transactions of The Korea Fluid Power Systems Society
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• v.5 no.4
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• pp.32-37
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• 2008

For the bucket tip position control of the excavator, a traditional hydraulic excavator system was exchanged into an electro-hydraulic one. EPPR valves are attached to the traditional MCV and hydraulic joysticks are replaced by electronic ones to develop the electro-hydraulic system. To control the electronic pump with a good performance, the control logic for the pump is deduced from the AMESim simulation and the experimental method on the test bench. To get a good position control performance of the excavator bucket tip, PI+AntiWindup controller is selected as a position controller. The experimental results showed the good controllability for the electro-hydraulic excavator system on the test bench.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.9
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• pp.103-111
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• 2009

Multi-climbing hydraulic robots are used to lift construction factory (CF) synchronously for applications in the automation of a high-rise building construction. In this study, synchronous motion controller is proposed for the hydraulic robots, whose strategy is not only to make each robot follow the reference path basically by sliding-mode control, but also to synchronize motions of two adjacent cent robots consecutively by cross-coupled control technique. Simulations are performed by using SIMULINK for a system similar to a practical application that includes unbalance in CF and wind disturbance. The results show that the proposed controller significantly reduces synchronous errors, compared to the individual controller for each hydraulic robot.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.11
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• pp.25-33
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• 1997

This study deals with controlling the velocity of Electr-Hydraulic servo system through the non-stan-dard PIC control. This was done as follows. First, we modeled nonlinearised model and linearised model, second designed analytic program for electro-hydraulic servo system velocity control Lastly, to im- prove dynamic characteristics of system we designed non-standard PID contoller and verifed throughth experi- ment and MATLAB program, commercial used software.