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Pontryagin’s Minimum Principle (PMP)를 이용한 하이브리드 전기차의 주행 제어 최적화
김남욱(Namwook Kim),임원식(Wonsik Lim),오창은(Chang Eun Oh),변상민(Sangmin Byun),차석원(Suk Won Cha) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
Several optimal control ideas for Hybrid Electric Vehicles (HEVs) were proposed in the literature. The representative optimal concept based on the bellman’s optimality, Dynamic Programming, guarantees a global optimal solution which could be obtained from an optimal field. In this paper, we suggest the Pontryagin’s minimum principle as an optimal control concept, in which the principle produces necessary conditions that the optimal control trajectory must satisfy. From a static model, the optimal results solved from PMP show that the results are really close to the results solved from DP, which should be supposed to be a global optimal solution. The differences between the results solved from PMP and the results solved from DP are only under 1 %. By the optimal control concept, PMP, we could build a real-time optimal controller because the technique is fundamentally based on an instantaneous optimal concept, which means that the control idea based on PMP is very useful if we have an intelligent model to approximate the costate in real-time driving.
5주간의 저강도 혈류제한 저항성운동과 중강도 저항성운동이 마른 비만 여성의 신체조성 및 혈중지질에 미치는 영향
김남욱 ( Namwook Kim ),이동민 ( Dongmin Lee ),이세원 ( Sewon Lee ) 한국운동생리학회(구 한국운동과학회) 2021 운동과학 Vol.30 No.1
PURPOSE: The primary objective of this study was to investigate and compare the effects of 5 weeks resistance training protocols (i.e., low-load blood flow restriction resistance training and moderate-load resistance training) especially on blood lipids, muscle strength, anaerobic power and body composition in young normal weight obese women. METHODS: Twenty-nine young normal weight obese women were randomly divided into three groups: blood flow restriction resistance training (BFR-RT, n=9), resistance training (RT, n=10) and non-training control (CON, n=10). BFR-RT group fitted a pneumatic cuff over the upper and lower extremities by using Kaatsu Nano equipment to apply the same pressures with each systolic blood pressure. The subjects in the BFR-RT group performed the training with 40% of 1RM and the RT group executed the resistance training with their 60-70% of 1RM. Both groups had performed the resistance training protocols twice per week for 5 weeks, and each training protocol consisted of bench press, barbell row, squat, and lunge. RESULTS: There were no changes in body weight, fat mass, BMI and %body fat in all groups after interventions for 5 weeks. However, the anaerobic power was significantly increased in both BFR-RT and RT groups compared to the CON group. Interestingly, only in the RT group, muscle mass and high-density lipoprotein cholesterol were significantly increased after the intervention. CONCLUSIONS: In conclusion, this study suggests that moderate-intensity RT is better than low-intensity BFR-RT to improve muscle mass and high-density lipoprotein cholesterol in young normal weight obese women.
김남욱(Namwook Kim),양시우(Siu Yang),김기남(Kinam Kim),장현목(Hyeonmog Jang),박영일(Yeong-il Park) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Coupler systems of trains are composed of buffer or hydraulic elements. These coupler systems can protect the train against the collision because the systems absorb the impact of the collision. The dynamic behavior of the coupler systems depends on the number of the cars which compose the train and stiffness of the cars. To analyze the dynamic behavior of the coupler systems, simulator is introduced in this paper, by which maximum force of the coupler systems and velocity of the cars can be calculated. In general, the first coupler which is attached at the front of the train gets the maximum force at simulation, and the maximum force of the first coupler doesn't relate to the number of the train when the number is bigger than three. The maximum force of the first coupler, however, increases along the stiffness of the cars because the maximum force increases as the period of the impact is shorten. The period approximately can be acquired from the stiffness of the coupler systems and the stiffness of the cars, so the maximum force, which affects the life time of the coupler systems, can be optimized if the coupler system is well designed.
김남욱(Namwook Kim),이대흥(Dae Heung Lee),양시우(Siu Yang),박영일(Yoeng-il Park),차석원(Suk Won Cha) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Hybrid system has two compatible power resources, an engine and a battery, and the strategies to control these two power resources cannot be simplified as an explicit algorithm because we'd like to sustain the state of charge of the battery within reasonable revel. Expect debating on how we can make optimal controllers, we might be able to draw the optimal trajectory with optimization methods if we already knew about the schedule of the driving cycle. These paper studies the optimization method of the fuel consumption for hybrid electrical vehicles with the method of Dynamic Programming, which was introduced Richard Bellman. DP is an effective method to get optimal trajectories when the systems have complicated and nonlinear behavior, and where there are several intricate constraints for control variables. We also discussed about the analytical approach for these optimal problems with a method of calculus of variation, which gives us the intuition about the optimal control of the hybrid system.
김남욱(Namwook Kim),양시우(Siu Yang),양호림(Horim Yang),조성태(Sungtae Cho),임원식(Wonsik Lim),차석원(Suk won Cha) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Dual mode hybrid systems are composed of few combined planetary gear sets. One planetary gear set has two DOF(degree of freedom) and the DOF increases when planetary gear sets are added, so it is complicate to analyze the systems. Methodologies of combining the planetary gear sets can be various methods, but it is needed that the methodologies have consistency. To the consistency, the equivalent parameters, α', β', R'a, R'b are introduced in this paper, and the arbitrary system, E-IVT(Electric Infinitely Variable Transmission) developed by Renault, is converted to the equivalent system with these parameters. Furthermore, the system efficiency can be represented by these parameters at hybrid mode, and the strategies of controlling the compound split can be improved by the analysis of the compound splits in this paper.
김남욱(Namwook Kim),양호림(Horim Yang),조성태(Suntae Cho),박영일(Yoeng-il Park),차석원(Suk won Cha) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Control1ing of HEV(Hybrid Electric Vehicle) is not easy going work because the vehicle has two or more degrees of freedom. To control a dual mode hybrid system, two-mode HEV which is composed of compound planetary gear systems, comprehension of the systems is most important. The compound planetary gear systems can be extended to other hybrid systems such as THS(Toyota Hybrid System), a mild hybrid system and so on, so the strategy of controlling the compound planetary gear systems is adapted to other hybrid systems. This paper studies the method of establishing dynamic equation of the compound planetary gear system and the strategy of controlling the system. An optimization of the system is also an important problem which is solved at supervisory controller, and the optimized results are introduced in this paper, but the method of the optimization is not issued in this paper. This paper doesn't deal a supervisory control but a component control. By the efficient component control strategy, the system operates on near the optimum points.
실험적 해석을 기반으로 한 연결기용 완충기의 등가 모델
김남욱(Namwook Kim),장현목(Hyun-mok Jang),김기남(Kinam Kim),박영일(Yeong-il Park) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Collision of trains might do damage the body of the trains when the speed of impact is high. To reduce the damage of the impact, it needs an appropriate coupling system which can absorb the impact energy. Former coupling systems have only buffer system for absorbing the energy of the impact, but these days, the coupling system which includes the buffer system and hydraulic system can absorb more energy than former system. This paper studies the performance simulation based on the experimental results. By the simulation, we can predict the maximum force of the impact if we know the characteristic of the system. Experiments for impact of trains are far expensive, and it takes a long time. Simulation, however, can be easily composed, but the higher accuracy of the simulation is needed to replace the experiment. We are going to make a simulator which has the equivalent models based on the experimental results though the simulator in this paper does not show remarkable coincident with the experimental results. We introduce the concept of the simulator.