• Journal of Ocean Engineering and Technology
• /
• v.30 no.5
• /
• pp.374-380
• /
• 2016

The large drift and angle of attack motion of an ROV (Remotely operated vehicle) cannot be modeled using the typical hydrodynamic coefficients of conventional straight running AUVs and specific slender bodies. In this paper, the ROV hull is divided into several simple-shaped components to model the hydrodynamic force and moment. The hydrodynamic force and moment acting on each component are modeled as the components of added mass force and drag using the known values for simple shapes such as a cylinder and flat plate. Since an ROV is operated under the water, the only environmental force considered is the current effect. The target ROV dealt with in this paper has six thrusters, and it is assumed that its maneuvering motion is determined using a thrust allocation algorithm. Tracking simulations are carried out on the ship’s surface near the stern, bow, and midship sections based on the modeling of the hydrodynamic force and current effect.

• Journal of the Korean Society for Precision Engineering
• /
• v.10 no.1
• /
• pp.126-133
• /
• 1993

Conventional cutting(CC) and Ultrasonic Vibration Cutting(UVC) of 20[KHz] are practised with standard lathe for fine ceramics(A1$_{2}$O$_{3}$. UVC is suggested to good cutting method for difficult-to-machine-materials and it is known to excellent cutting method to super precision cutting and elevation of productibility for general, nonferrous matals. In this research, main results to be obtained are as follows: 1. From the CC and UVC results by general lathe with sintering diamond tool, the surface roughness and roundness are improved in UVC. Also tool life is longer in UVC than CC. From the observation of machined surface, it is found that brittle fracutural material remove occured in fine ceramics cutting. 2. It is verified that the thrust force is the biggest in fine ceramics cutting, principal force is the next, and feed rate force the third and it is appear a little, on the other hand the principal force is the biggest in metal cutting, feed rate frece is the second, and thrust force is the next.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.3
• /
• pp.28-35
• /
• 2013

Micro electrical discharge machining (EDM) as a non-contact machining process is very effective for micromachining with a thin electrode because of its low machining reaction force. The micro-electrode machining device has the advantage of maintaining high precision through the whole processes and uses a feeding wire in the thin electrode tool manufacturing process. This study describes the design and evaluation of a micro-electrode machining device using optical photo-interrupter. The electrode was fabricated by reverse electrical discharge machining. The performance of designed system was evaluated to measure tension force according to feed speed of wire. This system for micro electrode fabrication proves the feasibility in the micro-EDM process of the micro holes and parts for industrial applications.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.993-996
• /
• 2000

A brushless linear motor is suitable for a high-accuracy servo mechanism. It is also suitable for operation with higher speed and precision. Since it does not involve some sort of mechanical coupling, linear driving force can be applied directly. Basic models including magetomotive force and electromotive forces are introduced and simplified. Both conventional PID and fuzzy controllers are implemented and performance results using those controllers are compared. Along with better simulated performance observed using fuzzy controller, further fabrication is to be included with various empirical results. Several system operational characteristics have been observed. Typical nonlinearities as friction, cogging and torque or thrust ripple that might deteriorate system performance would be tackled using presumably effective method such as neural network based learning controller.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.981-984
• /
• 1997

This paper deals with the relation of cutting conditions and damaged layer by investigating cutting force, cutting temperature and residual stress in high speed machining. Damaged layer was measured using optical microscope on samples prepared by metallographic techniques. The scale of this damaged layer depends upon characteristics of cutting force and cutting temperature. Damaged layer depth increases with feed per tooth and radial depth. In a different another way, damaged layer remains almost unchanged according to spindle speed. Therefore, the effective method for decreasing damaged layer is that cut down feed per tooth and radial depth.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.2
• /
• pp.123-134
• /
• 1995

In this paper, the fast force algorithm has been studied so that it is used to calculate cutting forces and to develope the NC verification system. The NC verification using the fast force algorithm can verify excessive cutting force which is the cause of deflection and breakage of tool, and adjust the feed rate and spindle speed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2005.05a
• /
• pp.97-102
• /
• 2005

This paper presents feed rate optimizaton of a PMLSM driven feed-slide for mininum vibrations by smoothing velocity curve with finite jerk. First of all, the PMLSM was designed and made to reduce detent force. Next, a PMLSM driven feed-slide system was mathematically modeled as a 4-degree-of-freedom lumped parameter model. The key idea of our vibration minimization method is to find out the most appropriate smooth velocity curve with finite jerk. The validity of our proposed method has been verified by comparing computer simulation results of the feed-slide model with experimental ones.

• Animal Bioscience
• /
• v.37 no.2
• /
• pp.274-283
• /
• 2024

Objective: The aim of the study was to evaluate the physicochemical properties (nutrient composition, pH, water content and activity, sorption properties) and mechanical properties (compression force and energy) of granulated feed mixtures with various inclusion levels of crude fibre concentrates ARBOCEL and VITACEL for broiler chickens, i.e. +0.0% (control group - group C), +0.3%, +0.8%, +1.0%, +1.2%. Methods: The feed mixtures were analyzed for their physicochemical properties (nutrient composition by near-infrared spectroscopy, pH with the use a CP-401 pH meter with an IJ-44C glass electrode, water content was determined with the drying method and activity was determined with the Aqua Lab Series 3, sorption properties was determined with the static method) and mechanical properties (compression force and energy with the use TA-HD plus texture analyzer). The Guggenheim-Anderson-de Boer (GAB) model applied in the study correctly described the sorption properties of the analyzed feed mixtures in terms of water activity. Results: The fibre concentrate type affected the specific surface area of the adsorbent and equilibrium water content in the GAB monolayer (p≤0.05) (significantly statistical). The type and dose of the fibre concentrate influenced the dimensionless C and k parameters of the GAB model related to the properties of the monolayer and multilayers, respectively (p≤0.05). They also affected the pH value of the analyzed feed mixtures (p≤0.05). In addition, crude fibre type influenced water activity (p≤0.05) as well as compression energy (J) and compression force (N) (p≤0.001) (highly significantly statistical) of the feed mixtures. Conclusion: The physicochemical analyses of feed mixtures with various inclusion levels (0.3%, 0.8%, 1.0%, 1.2%) of crude fiber concentrates ARBOCEL or VITACEL demonstrated that both crude fiber types may be used in the feed industry as a feedstuff material to produce starter type mixtures for broiler chickens.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.45 no.3
• /
• pp.104-114
• /
• 2022

The purpose of using coolant in machining is both to increase a tool life and also to prevent product deformation and thus, stabilize the surface quality by lubricating and cooling the tool and the machining surface. However, a very small amount of cutting mist should be used because chlorine-based extreme pressure additives are used to generate environmental pollutants in the production process and cause occupational diseases of workers. In this study, medical titanium alloy (Ti-6Al-7Nb) was subjected to a processing experiment by selecting factors and levels affecting cutting power in the processing of the Aerosol Dry Lubrication (ADL) method using vegetable oil. The machining shape was a slot to sufficiently reflect the effect of the cutting depth. As for the measurement of cutting force, the trend of cutting characteristics was identified through complete factor analysis. The factors affecting the cutting force of ADL slot processing were identified using the reaction surface analysis method, and the characteristics of the cutting force according to the change in factor level were analyzed. As the cutting speed increased, the cutting force decreased and then increased again. The cutting force continued to increase as the feed speed increased. The increase in the cutting depth increased the cutting force more significantly than the increase in the cutting speed and the feed speed. Through the reaction surface analysis method, the regression equation for predicting cutting force was identified, and the optimal processing conditions were proposed. The cutting force was predicted from the secondary regression equation and compared with the experimental value.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.7
• /
• pp.1555-1562
• /
• 1995

This study represents the non-dimensional cutting force model. With the non-dimensional cutting force model it is possible to estimate efficiently the maximum cutting force during one revolution of cutter. Using the non-dimensional cutting force model, the feed rate and spindle speed are adjusted so as to satisfy the maximum cutting force and maximum machining error. To verify the accuracy and efficiency of the non-dimensional cutting force model, a series of experiments were conducted, and experimental results proved and verified the non-dimensional cutting force model. The NC toolpath verification system developed in this paper uses the non-dimensional cutting force model, so that it is effective for calculating the cutting force and adjusting the cutting conditions.