• International Journal of Aeronautical and Space Sciences
• /
• 제18권3호
• /
• pp.522-534
• /
• 2017

According to the characteristics of salvo attack for the multiple flight vehicles (MFV), the design of cooperative guidance law can be converted into the consensus problem of multi-vehicle system through the concept of multi-agent cooperative control. The flight vehicles can be divided into leader and followers depending on different functions, and the flight conditions of leader are independent of the ones of followers. The consensus problem of leader-follower multi-vehicle system is researched by graph theory, and the consensus protocol is also presented. Meanwhile, the finite time guidance law is designed for the flight vehicles via the finite time control method, and the system stability is also analyzed. Whereby, the guidance law can guarantee the line of sight (LOS) angular rates converge to zero in finite time, and hence the cooperative attack of the MFV can be realized. The effectiveness of the designed cooperative guidance method is validated through the simulation with a stationary target and a moving target, respectively.

• 로봇학회논문지
• /
• 제9권3호
• /
• pp.147-153
• /
• 2014

In this paper, we proposed a new algorithm of the guidance line extraction for autonomous weeding robot based on infrared vision sensor in wet paddy. It is the critical process for guidance line extraction which finds the central point or area of rice row. In order to improve accuracy of the guidance line, we are trying to use the morphological characteristics of rice that the direction of rice leaves have convergence to central area of rice row. Using Hough transform, we were represented the curved leaves as a combination of segmented straight lines on binary image that has been skeletonized and segmented object. A slope of the guidance line was gotten as calculate the average slope of all segmented lines. An initial point of the guidance line was determined that is the maximum pixel value of the accumulated white columns of a binary image which is rotated the slope of guidance line in the opposite direction. We also have verified an accuracy of the proposed algorithm by experiments in the real wet paddy.

• International Journal of Aeronautical and Space Sciences
• /
• 제18권4호
• /
• pp.719-728
• /
• 2017

This paper proposes a synthesis of new guidance law to generate an evasive maneuver against enemy's missile interception while considering its impact angle, acceleration, and field-of-view constraints. The first component of the synthesis is a new function of repulsive Artificial Potential Field to generate the evasive maneuver as a real-time dynamic obstacle avoidance. The terminal impact angle and terminal acceleration constraints compliance are based on Time-to-Go Polynomial Guidance as the second component. The last component is the Logarithmic Barrier Function to satisfy the field-of-view limitation constraint by compensating the excessive total acceleration command. These three components are synthesized into a new guidance law, which involves three design parameter gains. Parameter study and numerical simulations are delivered to demonstrate the performance of the proposed repulsive function and guidance law. Finally, the guidance law simulations effectively achieve the zero terminal miss distance, while satisfying an evasive maneuver against intercept missile, considering impact angle, acceleration, and field-of-view limitation constraints simultaneously.

• Journal of Biosystems Engineering
• /
• 제26권4호
• /
• pp.363-370
• /
• 2001

This study intended to estimate the willingness-to-pay amount by farmers for the automatic guidance technology of Combine. Contingent Valuation Method was employed for this estimation using survey data from 65 Combine using farmers. Based on the dichotomous choice model, farmers’willingness-to-pay for the automatic guidance technology was ranged from ￦4,772,000(median) to ￦5,268,000(mean). The estimated willingness-to-pay by the for the new technology was approximately one quarter of the average value based on the willingness-to-pay for the new technology was approximately one quarter of the average value of Combine in sample farms. This implies that there is an economic rationals for developing the new technology as long as it will be available with the cost less than the amount of estimated willingness-to-pay.

• 로봇학회논문지
• /
• 제11권1호
• /
• pp.1-8
• /
• 2016

In this paper, we propose a new algorithm of the guidance line extraction for autonomous agricultural robot based on vision camera in paddy field. It is the important process for guidance line extraction which finds the central point or area of rice row. We are trying to use the central region data of crop that the direction of rice leaves have convergence to central area of rice row in order to improve accuracy of the guidance line. The guidance line is extracted from the intersection points of extended virtual lines using the modified robust regression. The extended virtual lines are represented as the extended line from each segmented straight line created on the edges of the rice plants in the image using the Hough transform. We also have verified an accuracy of the proposed algorithm by experiments in the real wet paddy.

• International Journal of Aeronautical and Space Sciences
• /
• 제8권1호
• /
• pp.46-53
• /
• 2007

In this paper, a guidance law for vision-based automatic landing of unmanned aerial vehicles (UAVs) is proposed. Automatic landing is a challenging but crucial capability for UAVs to achieve a fully autonomous flight. In an autonomous landing maneuver of UAVs, the decision of where to landing and the generation of guidance command to achieve a successful landing are very significant problem. This paper is focused on the design of guidance law applicable to automatic landing problem of fixed-wing UAV and rotary-wing UAV, simultaneously. The proposed guidance law generates acceleration command as a control input which derived from a specified time-to-go ($t_go$) polynomial function. The coefficient of $t_go$-polynomial function are determined to satisfy some terminal constraints. Nonlinear simulation results using a fixed-wing and rotary-wing UAV models are presented.

• Journal of Mechanical Science and Technology
• /
• 제16권6호
• /
• pp.770-775
• /
• 2002

In this paper, a game optimal receding horizon guidance law (GRHG) is proposed, which does not use information of the time-to-go and target maneuvers. It is shown that by adjusting design parameters appropriately, the proposed GRHG is identical to the existing receding horizon guidance law (RHG), which can intercept the target by keeping the relative vertical separation less than the given value, within which the warhead of the missile is detonated, after the appropriately selected time in the presence of arbitrary target maneuvers and initial relative vertical separation rates between the target and missile. Through a simulation study, the performance of the GRHG is illustrated and compared with that of the existing optimal guidance law (OGL).

• 한국군사과학기술학회지
• /
• 제11권4호
• /
• pp.29-35
• /
• 2008

In this paper, a new guidance law to reduce sensitivity to the initial heading errors is proposed. In order for shaping the input weights over the flight, we introduce the distribution functions expressed in terms of time-to-go and its inverse term. By applying the optimal control theory with the synthesized weights, the homing guidance law is derived. Also the characteristics of the proposed law are examined. Various computer simulations show the good performance of the proposed guidance.

• 한국항공우주학회지
• /
• 제49권8호
• /
• pp.637-648
• /
• 2021

본 논문에서는 한국형 우주비행기(KSP)에 대한 새로운 재진입 유도를 제안하고자 한다. 제안된 방법은 우주 왕복선 유도 개념과 유사하게 다양한 비행경로 제약조건과 경계조건을 만족시키는 기준 항력 프로파일을 미리 결정하고, 결정된 기준 항력 프로파일을 추종하는 방식으로 유도명령이 구현된다. 이를 위해 본 연구에서는 항력 동역학을 조사하였으며, 그 결과 항력과 비행경로각의 동역학적 응답 특성이 상당히 다르다는 사실이 밝혀졌다. 이 사실을 바탕으로 제안한 유도명령은 시간분리 기법과 궤환선형화 방법을 사용하여 결정된다. 제안한 유도기법의 주요 특징은 간단한 구조와 명확한 작동 메커니즘에 있다. 따라서 제안된 방법은 기존 방법에 비해 구현이 간단하다. 본 논문에서는 제안된 방법의 성능을 조사하기 위해 수치 시뮬레이션을 수행한다.

• International Journal of Aeronautical and Space Sciences
• /
• 제10권1호
• /
• pp.30-36
• /
• 2009

Many formation guidance laws have been proposed for VAV formation flight. Since most autonomous formation flight methods require various active communication links between the vehicles to know motion information of other vehicles, damage to the receiver or the transmitter and communication delay are critical problem to achieve a given formation flight mission. Therefore, in this point of view, the method that does not need an inter-vehicle communication is preferred in the autonomous formation flight. In this paper, we first summarize the formation guidance law without an inter-vehicle communication using feedback linearization and sliding mode control proposed in previous study. We also propose the modified formation guidance law with robust disturbance observer, which can provide significantly better performance than previously mentioned guidance law in case that other vehicles maneuver with large accelerations. The robust disturbance observer can estimate uncertainties generated by acceleration of leader vehicle. By eliminating the uncertainties using the estimated uncertainties, VAVs are able to achieve the tight formation flight. The performance of the proposed approach is validated by numerical simulations.