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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Drive and Control
Journal Basic Information
Journal DOI :
Korea Society of Fluid Power & Construction Equipments
Editor in Chief :
Volume & Issues
Volume 13, Issue 3 - Sep 2016
Volume 13, Issue 2 - Jun 2016
Volume 13, Issue 1 - Mar 2016
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Synchronous Control of an Asymmetrical Dual Redundant EHA
Lee, Seong Ryeol ; Hong, Yeh Sun ;
Journal of Drive and Control, volume 13, issue 2, 2016, Pages 1~9
DOI : 10.7839/ksfc.2016.13.2.001
In this paper, an elementary force fighting problem was investigated. The problem is encountered when a double-rod type EHA(electro-hydrostatic actuator) is combined with a single-rod type EHA to build a redundant actuator system with synchronized motion. When the rod-side chambers of the two different types of EHAs have the same effective piston areas and are simultaneously pressurized by an external load, the two EHAs behave identically, sharing the external load equally. However, when the piston head-side chamber of the single rod type EHA, having a larger effective area than the rod-side chamber, is pressurized by the external load, an abnormal force fighting between the two EHAs occurs, unless their pump speeds are properly decoupled. In this study, the output drive forces of each EHA were obtained from the cylinder pressure signals and applied to the position control for each EHA to maintain the balance between their pump speeds. Adding minor force difference feedback loops to the position control, the force fighting phenomena could be eliminated and steady state synchronization errors were reduced. The power consumption of the pumps also could be remarkably reduced, avoiding unnecessarily high load pressures to the pumps.
Improved Design of Hydraulic Circuit of Front-end Loader for Bump Shock Reduction of an Agricultural Tractor
Cho, Bong Jin ; Ahn, Seong Wook ; Lee, Chang Joo ; Yoon, Young Hwan ; Lee, Soo Seong ; Kim, Hak Jin ;
Journal of Drive and Control, volume 13, issue 2, 2016, Pages 10~18
DOI : 10.7839/ksfc.2016.13.2.010
A front-end loader (FEL) mounted on an agricultural tractor is one of the most commonly used implements to mechanize routine agricultural tasks. When the FEL is used with a loaded bucket, careful operation is required to maintain safety and avoid spillage when the tractor passes a bump because a change in the gravity center of the tractor due to varied loadings can affect the stability of the tractor. Use of a boom suspension system consisting of accumulators and orifice dampers can be instrumental in reducing pitching vibrations while increasing the handling performance of the FEL-mounted tractor. The objective of this research was to reduce bump shocks by adding an orifice and a flow control valve to the original hydraulic circuit composed solely of accumulators. A simulation study was performed using the SimulationX program to investigate the effects of an accumulator and an orifice-throttle damper on bump shocks. Results showed that the peak pressure on a boom cylinder and the vertical acceleration of a bucket were significantly affected by use of both an accumulator and an orifice damper. In a field test conducted with a 75-kW tractor, the peak pressure of the boom cylinder, and the root mean square (RMS) vertical acceleration of the bucket and seat were reduced by on average, 23.0, 42.2, and 44.9% respectively, as compared to those measured with the original accumulator system, showing that an improved design for the accumulator hydraulic circuit can reduce bump shocks. Further studies are needed to design a tractor suspension system that includes the effects of cabin suspension and tires as well as dynamic analysis.
A Study on Contribution Analysis using Operational Transfer Path Analysis based on the Correlation between Subjective Evaluation and Zwicker`s Sound Quality Index for Sound Quality of Forklifts
Kim, Beom Soo ; Yang, Soon Yong ;
Journal of Drive and Control, volume 13, issue 2, 2016, Pages 19~25
DOI : 10.7839/ksfc.2016.13.2.019
Recently, drivers have begun to regard comfort in the cabin as one of the most important factors in construction equipment like forklifts. Accordingly, it has become more important to design a forklift cabin with a better sound quality as well as lower sound level, which can make a driver more comfortable. In this paper, the correlation between subjective evaluation and Zwicker`s sound quality index was analyzed through a blind test by a few workers in forklifts and other construction equipment in several countries. Correlation analysis showed that Loudness and Sharpness were ranked in sequence, and tendencies were different from country to country. Also, contribution analysis for Loudness and Sharpness using operational transfer path analysis (OTPA), which is widely used in the field of noise, vibration, and harshness (NVH), was performed. However, Loudness and Sharpness cannot be used with OTPA directly because there are no linear relationships between the sources and receivers. In this paper, both are calculated by applying the DIN 45631 method with a contribution rate (%) of 1/3 Octave Sound Pressure Level by OTPA method in addition to considering spectral masking.
A Study of Hydraulic Actuator Based On Electro Servo Valve For A Walking Robot
Cho, Jung San ;
Journal of Drive and Control, volume 13, issue 2, 2016, Pages 26~33
DOI : 10.7839/ksfc.2016.13.2.026
This paper describes of a mathematical and real experimental analysis for a walking robot which uses servo valve driven hydraulic actuator. Recently, many researchers are developing a walking robot based on hydraulic systems for the difficult and dangerous missions such as walking in the rough terrain and carrying a heavy load. In order to design and control a walking robot, the characteristics of the hydraulic actuators in the joint through the view point of walking such as controllability and backdrivability must be analyzed. A general mathematical model was used for analysis and proceeds to position and pressure changes characteristic of the input and backdrivability experiment. The result shows the actuator is a velocity source, had a high impedance, the output stiffness is high in contact with the rigid external force. So stand above the controller and instruments that complement the design characteristics can be seen the need to apply a hydraulic actuator in walking robot.
Optimization of Design Parameters of a EPPR Valve Solenoid using Artificial Neural Network
Yoon, Ju Ho ; Nguyen, Minh Nhat ; Lee, Hyun Su ; Youn, Jang Won ; Kim, Dang Ju ; Lee, Dong Won ; Ahn, Kyoung Kwan ;
Journal of Drive and Control, volume 13, issue 2, 2016, Pages 34~41
DOI : 10.7839/ksfc.2016.13.2.034
Unlike the commonly used On/Off solenoid, constant attraction force which is independent of plunger displacement is a considerably important characteristic to proportional solenoid of the EPPR Valve. Attraction force uniformity is mainly affected by the internal shape design parameters. Due to a number of shape design parameters, the optimal parameter values are very complex and time consuming to find by trial and error method. Much research has been conducted or are still in progress to find the optimal parameter values by applying various optimization techniques like Genetic Algorithm, Evolution Strategy, Simulated Annealing, or the Taguchi method. In this paper, the design parameters which have primary effects on the attraction force uniformity and the average attraction force are decided by main effects analysis of Design of Experiments. Optimal parameter values are derived using finite-element analysis and a neural network model.
An Experimental Study on Static Characteristics of Servo Valves using Transmission Line Pressures
Kim, Sung Dong ; Joo, Byeol Jin ; Yun, So Nam ;
Journal of Drive and Control, volume 13, issue 2, 2016, Pages 42~50
DOI : 10.7839/ksfc.2016.13.2.042
The conventional technique to measure the hysteresis and the null of servo valves is defined in ISO 10770-1 and based on load flow signal of the servo valve. A new technique based on the transmission line pressures is suggested in this study. The new measuring method was verified through a series of experiments. No hysteresis was observed between the spool displacement and the transmission line pressures, load pressure or each chamber pressure. Some hysteresis was observed between valve input and pressures, which was found to be the same as those of load flow and spool displacement for the valve input. By using the chamber pressures, the hysteresis and the null are easier to measure than the load pressure or differential pressure between those two chamber pressures because the chamber pressures showed sharp edges.
Clamping force control of injection molding machine using 2-way cartridge valve based logic circuit
Cho, Seung Ho ;
Journal of Drive and Control, volume 13, issue 2, 2016, Pages 51~58
DOI : 10.7839/ksfc.2016.13.2.051
The present study deals with the issue of clamping force control of an injection molding machine using 2-way cartridge valve based logic circuit. The operating principle for the cartridge valve is described with its construction and static opening behavior. Basic module circuits are designed first and analysed according to the basic functions. Then they are combined with a virtual design model for the clamping mechanism to simulate the control performance of the overall system. The backlash inherent in the mechanism is considered while evaluating the time-delay in the process of clamping force build-up. The effects of a couple of design parameters in backlash, i.e., interval and stiffness have been demonstrated in the time-domain.