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Review of the Latest Research on Snake Robots Focusing on the Structure, Motion and Control Method
Junseong Bae,Myeongjin Kim,Bongsub Song,Junmo Yang,Donghyun Kim,Dongwon Yun,Maolin Jin 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.10
Unlike other types of robots, the snake robot performs unique motions and can move on various terrains such as gravel, stairs, and pipes. Therefore, snake robots are used as exploration robots, rescue robots, and disaster robots. However, the snake robot requires to choose actuators, sensors, and controllers appropriately for overcoming the real environment by using various types of gait. In this paper, we summarized research trends of snake robots for understanding the state of the art technologies of snake robots. We focused on the various development of the snake robots based on previous snake robots’ literature. To look more closely at these research trends, we introduced trends of motion, actuators, sensors, kinematic structure design, control method and application that are related with the snake robots. Snake robots can conduct several motions such as sine wave, side winding, rolling, and so on. These motions are generated by servo motors, DC motors, pneumatic actuators, and smart materials like SMA, IPMC, etc. Also, snake robots require certain data from sensors and proper kinematic structure design to achieve their purposes of operation. Sensors such as camera, force sensor, distance sensor, and kinematic structure design such as passive wheel and motorized wheel can be applied in snake robot for implementing the function or increasing the driving performance. Based on these physical components, the control method is important for operating the snake robot. Navigating algorithms and overcoming terrains with restrictions on movement have been studied with a various control methods.
Junseong Lee,김영조 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.1
Four zirconium complexes containing fully deprotonated 2-(2H-benzo[d][1,2,3]triazol-2-yl)-4,6-di-tertpentylphenol were used as catalysts for the polymerization of ethylene. In the presence of methylalumoxane (MAO) as a cocatalyst, the precursors were highly active for polyethylene with bimodal or multimodal molecular weight distribution.
Optimal Guidance Law for Impact Angle and Acceleration Constraints with Time-Varying Gains
Junseong Kim,조성진 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.3
In this paper, we establish an optimal guidance law for impact angle and acceleration constraints (OGL-IAAC). The optimal guidance law for impact angle (OGL) is widely used due to its energy optimality and analytic solutions. However, acceleration constraints may degrade the performance of the OGL owing to the significant guidance command at the initial and terminal time and hence saturated acceleration values may generate guidance errors. We introduce a new weighting function based on the guidance command closed-form solution of the OGL to address this problem. Then, we derive a new guidance law by using Schwarz’s inequality. The proposed guidance law generates time-varying gains to ensure that the guidance command is within the acceleration constraint. Moreover, the gains converge to the same values as those of the OGL when the time-to-go approaches zero. The proposed guidance law is demonstrated by simulations to investigate the performance and effect of varying coefficients of the weighting function.
A Case Study on Network Status Classification based on Latency Stability
( Junseong Kim ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.11
Understanding network latency is important for providing consistent and acceptable levels of services in network-based applications. However, due to the difficulty of estimating applications` network demands and the difficulty of network latency modeling the management of network resources has often been ignored. We expect that, since network latency repeats cycles of congested states, a systematic classification method for network status would be helpful to simplify issues in network resource managements. This paper presents a simple empirical method to classify network status with a real operational network. By observing oscillating behavior of end-to-end latency we determine networks` status in run time. Five typical network statuses are defined based on a long-term stability and a short-term burstiness. By investigating prediction accuracies of several simple numerical models we show the effectiveness of the network status classification. Experimental results show that around 80% reduction in prediction errors depending on network status.