• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.481-486
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• 2002

Automation of Field Robot has many advantages for efficiency and convenience. In this paper, mathematical equation of field robot is established and automation system is constructed. Hydraulic and Dynamic equation of field robot are constructed in this paper. Inputs of system are angle data from each link (boom, arm, bucket, swing) and pressure data from in, out port of each cylinder. Outputs of system are voltage into electo-proportional valve.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.75-79
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• 2002

A hydraulic Excavator is applied for outdoor tasks in construction, agriculture and undersea etc. When a hydraulic Excavator works crane function tasks, most of disasters happen. In this study, In order to preventing these disasters, the safety equipment algorithm for crane working is developed, and the safety equipment algorithm for crane working is being developed. The proposed control algorithm(Zero Moment Point) is designed to avoid overload. The hydraulic excavator for crane function must work within a maximum limit of load. To accurately detect a working load, pressure sensors of boom, arm cylinder, and angle sensors of boom, arm and bucket joint are used.

• Journal of Biosystems Engineering
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• 제37권5호
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• pp.287-295
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• 2012

Purpose: Some of the most representative approaches are to apply next generation technologies to save energy consumption, fully automated control system to appropriately maintain environmental conditions, and autonomous assistance system to reduce labor load and ensure operator's safety. Nevertheless, improvement of upcoming method for soil cultured greenhouse has not been sufficiently achieved. Geometrical complexity of ground in protected crop cultivation might be one of the most dominant factors in design of autonomous vehicle. While there is a practical solution fairly enough to promise an accurate travelling, such as autonomous sprayer guided by rail or induction coil, for various reasons including the limitation of producer's budget, the previously developed sprayer has not been widely distributed to market. Methods: In this study, we developed an autonomous sprayer considering travelling performance on geometrical complexity of ground in soil cultured greenhouse. To maintain a stable travelling and to acquire a real time feedback, common wire with 80 mm thick and body frame and sprayer boom. To evaluate performance of the prototype, tracking performance, climbing performance and spraying boom's uniform leveling performance were individually evaluated by corresponding experimental tests. Results: The autonomous guidance system was proved to be sufficiently suitable for accurate linear traveling with RMS as lower than approximately 10 cm from designated path. Also the prototype could climb $10^{\circ}$ of ground's slope angle with 40 kg of water weight. Uniform leveling of spraying boom was successfully performed within $0.5^{\circ}$ of sprayer boom's slope. Conclusions: Considering more complex pathways and coarse ground conditions, evaluations and improvements of the prototype should be performed for promising reliability to commercialization.

• 한국기계가공학회지
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• 제18권5호
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• pp.53-59
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• 2019

Continuous ship unloaders (CSUs) are used for the uninterrupted transport of material in processing industries, power plants, and harbors in accordance with the stream rate of the material. This study analyzed the structural integrity and fatigue life of a CSU structure using finite element structural analysis in ANSYS APDL software. The stress varied greatly depending on the luffing angle and the slew angle of the boom conveyor. The structural integrity of the CSU girder was evaluated by applying ASME BPVC Section VIII Division 2. The fatigue cycle at the angle with the greatest stress difference was calculated. The fatigue cycle was calculated by applying the JIS B 8821:2013 fatigue curve. It was confirmed that the fatigue cycle of the CSU satisfies the allowable fatigue of 200,000 cycles.

• 한국기계가공학회지
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• 제9권1호
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• pp.35-41
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• 2010

An overload limiter is used to prevent its overturning accident during an operation of a movable crane. Recently the indirect measuring method, which measures hoisting load and overturning moment of overload limiter, demands instead of the existing method, which measures only hoisting load. The indirectly measuring method is how to conduct the hoisting load and overturning moment as measuring the load of hydraulic cylinder for a luffing driving of boom. So we need to develop the multi-angular pin type load cell with the measuring angle of ${\pm}10$ degree instead of the existing load cell with the measuring angle of ${\pm}2$ degree. In this study the finite element analysis is conducted to evaluate the effect of the aspect ratio of measuring cross section on the measuring limit of the load cell to develop the many-angular pin type load cell. For this investigation, the aspect ratio of measuring cross section and load applying angle were adopted as design parameters and the stresses of measuring part were evaluated for each parameter.

• 드라이브 ㆍ 컨트롤
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• 제19권2호
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• pp.11-16
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• 2022

It is important to measure the excavator's work productivity that estimates the bucket's payloads on a process. If the bucket isn't filled at every working cycle, the excavator's operator has to drive the machine more to achieve his work quota. If bucket is filled over with the load, the other way around, the transferred object has to spread out on the workplace. That causes additional work to clean the site. This paper proposes a method that can estimate the bucket's payload to improve the excavator's work productivity. This method assumes that the excavator is a lumped mass system. And it uses a 3 points angle (boom link, arm link, swing) and 2 points pressure (boom cylinder's input port and output port) of measurable data. Depending on assumptions, the bucket's payload can be calculated by the payload's motion equation. And this suggested method can be verified by simple experiments.

• 드라이브 ㆍ 컨트롤
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• 제21권1호
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• pp.31-37
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• 2024

In this study, to prevent accidents in underground facilities during excavation, we developed a Lv.3 automated control system that can be configured as an electronic control system without changing the existing hydraulic system in a general excavator and utilized digital map information of underground facilities. We aimed to develop a strategy to prevent accidents caused by operator error. To implement this, a real-time excavator bucket end position recognition and control system was developed through angle measurement of the boom, arm, and bucket using an electronic joystick, RTK-GPS, and angle sensors. In addition, excavators are large, machine-based equipment, and it is difficult to control overshoot due to inertia with feedback control using position recognition information of the bucket tip. Therefore, feed-forward control is used to calculate the moving speed of the bucket tip in real-time to determine the target position. We developed a technology that can converge and verified the performance of the developed system through actual vehicle installation and field tests.

• 문화기술의 융합
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• 제5권3호
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• pp.263-269
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• 2019

본 연구에서는 붐 길이를 측정할 수 있는 센서, 붐 및 로더의 좌우측의 경사를 측정할 수 있는 각도센서 그리고 리프팅 시 무게를 측정할 수 있는 로드셀 등의 여러 센서를 장착한 다목적 로더의 특성과 운행에 관련된 데이터 값을 디스플레이하는 시스템을 구현하였다. 시스템의 구성은 다음 각종 센서로부터 값을 읽어와 이를 차량제어기에 보내고 제어기에서 계산한 전복률 결과와 기타 중요한 정보를 디스플레이 장치에 CANOpen 프로토콜을 이용하여 전달하게 하였다. 또한 전복률 계산에 있어서는 다목적 로더의 구조가 중장비에 속하는 크레인의 구조와 비슷하여 크레인 전복률 계산방식을 사용하였으며 좌우 경사도에 따른 전복 위험성은 실험을 통하여 전복가능성이 있는 좌우 경사각을 추출하였다. 본 연구를 통하여 중장비 차량의 상태를 관찰하며 전복 등의 비상 상황을 디스플레이 장치를 통해 사전 인지할 수 있게 하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.606-609
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• 1995

To stabilize a satellite, a spin stabilization method is used for attitude control. The spin stabilization uses the centrifugal force of a pendulum damper which is tilted long boom, to stabilize the unstable satellite. In this paper, an inverted pendulum system is implemented which is similar to the spin stabilization method. Study on the velocity of the rotation axis and the inverted pendulum's angle stability is shown. We designed a controller using a 32bit TMS320C31 DSP for the CPU and also performances by PLD control and Sliding Mode Control is compared.

• 대한기계학회논문집B
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• 제28권7호
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• pp.800-808
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• 2004

Wind tunnel test of an airplane model with forward swept wing was done in KARI LSWT to evaluate and measure the aerodynamic characteristics of initially designed configuration. Since the given wing planform did not fully satisfy the design requirements, local flow control devices such as vortilon, vortex generator and flow fence were used to delay separation and to enhance aerodynamic characteristics. Also decision making processes of design parameters such as vertical tail boom length, the location, size and the incidence angle of horizontal tail were discussed. The general aerodynamic characteristics of forward swept wing for various control surface deflection conditions of flap, aileron and elevator were also given.