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Sangyul Park,Hasun Lee,Dongjun Lee 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10
We propose CPG (central pattern generator) based robot control framework constructed based on: 1) the inverse model of the CPG that directly encodes resultant body motion of the robot in CPG parameters; and 2) the CPG parameter adaptation law that enforces robustness of the controller. These two components behaves as feedforward and feedback control for the CPG controlled robot, enabling us to achieve fast and robust generation of a desired body motion for robotic systems operated within complex environmental interaction. The inverse CPG model is constructed based on neural network along with autoencoder to efficiently deal with the dimension decrease from input to output of the model. Also, the CPG parameter adaptation is done with a concept of backpropagation, which is enabled by the adoption of smooth activation function for the inverse CPG model. For the development and verification of the proposed framework, simulation is conducted with two robotic systems, snake-like robot and pivotboard system.
( Sangyul Kim ),( Haruo Matsumura ),( Masaru Tanaka ) 한국폐기물자원순환학회(구 한국폐기물학회) 2015 한국폐기물자원순환학회 3RINCs초록집 Vol.2015 No.-
For the construction of a recycling-oriented society, utilization of kitchen waste, which accounts for more than 30% in Municipal Solid Waste (MSW), is important. However, incineration is the main treatment of MSW even for kitchen waste in Japan. This study examined a liquid fertilizer recycling system in the eastern region of Tottori Prefecture to promote the use of waste biomass such as kitchen waste and food waste. The results of this study showed voluntary participation of residents in separation, sealing the lid of the kitchen collection container with rubber, regular communication with users of liquid fertilizer to exchange information, and sequential contracts with businesses on the collection and treatment of food waste as well as sales of vegetables harvested in liquid fertilize were effective.
Sangyul Ha,박진형,Doohyeong Kim,Hyeon-Jin Son,Yong-Seok Lee 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7
Various mechanical tests are performed to evaluate mechanical characteristics. Tensile testing is an essential experimental method. Preparing equipment for accurately measuring mechanical properties is challenging because it is very expensive. Hence, tensile tests are performed except for some measuring instruments. The strain-measurement device is often excluded. Therefore, the outcomes of strain measurement methods differ. This study showed the difference in the elastic modulus depending on that in the strain measurement method (strain calculation based on (1) the strain between the grips and (2) that using a strain gauge or other strain measurement devices in the gauge length). Experiments and computational analyses were used to prove the outcome. A novel method to estimate the elastic modulus through a hybrid experimental method and finite element analysis is proposed because the elastic modulus can be lowered when calculating strain based on the deformation amount between grips.
Knock sensing and imaging from structural bending waves
Sangyul Ha,Areum Jang,이경준,손성호 한국통신학회 2022 ICT Express Vol.8 No.4
This paper presents a novel knock imaging technique for human-to-things interfaces. It allows any object to use its own surface as an imaging sensor. The methodology is to sense the structural bending waves caused by the knock and reconstruct the intensity image through the beamforming of the wave signals. To verify this, we prepare a thin piezoelectric sensor array on a square plate. The performances are evaluated by measuring the beam peak, beamwidth, and sidelobe level in the reconstructed image. Finally, a real finger knock test is demonstrated, showing an image reconstruction that the position error is only 3 mm.
Sangyul Lee,Jongyoon Lee,Seungkwon Hwang,Taejoong Wang,Youngbok Lee 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.9
To comply with the new non-road emission standards, final Tier 4, two big strategies have been applied to the 11 L heavy-duty diesel engine. The first strategy is to apply Exhaust gas recirculation and selectivity catalytic reduction system to meet the NOx limitation. The other one is to apply low swirl ratio (for higher volumetric efficiency) and multi-hole nozzle, a high pressure direct injection, and an optimized combustion system in order to reduce PM emission. Both strategies put a focus on the optimization of combustion system. In this study, a ULPC bowl concept applied in the previous works has been successfully verified in 11 L heavy-duty diesel engine with wellvalidated 3D combustion simulation, and the ULPC bowl shape has been geometrically optimized. A rough 0D calculation is used to calculate the fuel split ratio of the various ULPC bowl shapes. In the rated-power operating condition of the final Tier 4 engine which is deduced by 1D cyclic simulation, the optimal fuel split ratio of the injected fuel has been verified. Also, additional geometric optimization has been achieved without changing the optimal fuel split ratio. From these results, soot has been reduced by about 30% with ULPC optimum bowl shape against the Tier 3 re-entrant bowl shape.