• 제어로봇시스템학회논문지
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• 제13권6호
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• pp.560-567
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• 2007

The objective of this research is to optimize the designing parameters of the parallel manipulator with large orientation workspace at the boundary position of the constant orientation workspace (COW). The method uses a simple genetic algorithm(SGA) while considering three different kinematic performance indices: COW and the global conditioning index(GCI) to evaluate the mechanism's dexterity for translational motion of an end-effector, and orientation workspace of two angle of Euler angles to obtain the large rotation angle of an end-effector at the boundary position of COW. Total fifteen cases divided according to the combination of the sphere radius of COW and rotation angle of orientation workspace are studied, and to decide the best model in the total optimized cases, the fuzzy inference system is used for each case's results. An optimized model is selected as a best model, which shows better kinematic performances compared to the basis of the pre-existing model.

• 한국자동차공학회논문집
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• 제9권4호
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• pp.176-183
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• 2001

It is difficult to find out the kinematic characteristics of a vehicle suspension without the usage of CAE software. The application of CAE software into suspension kinematics and dynamics yields the more precise knowledge on the chassis design. In this study, the influence of the suspension geometry on the handling performances of a large-sized bus is investigated using the DADS software. The front and rear suspension of a large-sized bus are a rigid axle suspension with the four control links. The elastokinematic analysis is performed to evaluate the roll characteristics of the front and rear suspension. The elastokinematic responses are evaluated in terms of the roll center height and roll steer for various geometric parameters. The roll center height is mainly dependent on the vertical displacement of a panhard rod and the vertical displacements of lower control links affect the roll steer of a rear suspension. The parameter study with the change of rear suspension geometry is conducted to investigate the vehicle handling performances. This parameter study shows that the vertical displacement and orientation of a panhard rod influence the handling performances of a large-sized bus significantly.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.82-87
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• 1994

In this study, dynamic optimal design far a two degree-of-freedom anthropomorphic robot module is performed. Several dynamic design indices associated with the inertia matrix and the inertia power array are introduced. Analysis for the relationship between the dynamic parameters and the design indices shows that trade-offs exist between the isotropy and the dynamic design indices related to the actuator size. A composite design index is employed to deal with multi-criteria based design with different weighting factors, in a systematic manner. We demonstrate the fact that dynamic optimization is another significant step to enhance the system performances, followed by kinematic optimization.

• 한국정보통신학회논문지
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• 제20권9호
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• pp.1679-1687
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• 2016

이동로봇은 유연한 생산시스템이 필요한 산업현장에서 유용하게 사용된다. 이동로봇이 생산부품과 같은 기계적 부하를 싣고 정해진 경로를 따라 정확히 이동하여야 하며 통상 기구학적 제어기가 사용되고 있다. 그러나 부하가 매우 크고 비선형 마찰도 클 경우, 기구학적 제어기로 만족할 만한 제어성능을 기대할 수 없어서 동적 제어기가 연구되고 있다. 기존의 동적 제어기는 부하의 무게와 위치를 정확히 알아야 한다는 조건이 있다. 그러나 실제 기계적 부하는 빈번히 변하고 정확히 알 수 없으므로 기존의 동적제어기 성능에 한계가 있다. 따라서 기계적 부하를 정확히 알지 못해도 이동로봇의 동적제어가 작동하도록 경사감소학습을 이용하여 적응 PD 제어 방법을 본 논문에서 제안하였다. 여러 가지 부하 변동 조건하에서 다양하게 시뮬레이션 하여 본 논문의 적응 PD 제어 방법이 기존의 방법보다 폭넓은 수렴영역을 가지고 있음을 확인하였다.

• 한국운동역학회지
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• 제16권2호
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• pp.9-19
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• 2006

The purpose of this study was to analyze the kinematic variables of the lower limbs joints and the muscle activity for lower limbs during the level and downhill running. The subjects were 6 males of twenties and required to run on the level and downhill which was -7% grade treadmill at 8.3km/h. The running performances were filmed by high speed video camera and EMG signal was gained by ME3000P8 Measurement Unit. Rectus femoris(RF), Vastus lateralis(VL), Gluteus medius(GLU), Biceps femoris(BF), gastrocnemius medial head(GM), gastrocnemius lateral head(GL), Soleus(SO), Tibialis anterior(TA) were selected. The result of this study were as follows: 1. Ankle, knee, hip joint in downhill running showed less movement than the level running but, no significant difference. 2. VL and BF during the support phase in downhill running showed Iess muscle activity than the level running. but RF showed the opposite result. 3. GM, GL, SO adn TA during the supports phase in downhill running showed less muscle activity than the level running.

• 한국운동역학회지
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• 제15권1호
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• pp.177-195
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• 2005

The purpose of this study was to analyze the kinematic variables of ankle joints and EMG signal of the lower limbs muscle activity for the different walking speed. The subjects were 6 males of twenties. It was classified into three different walking speed-0.75m/s, 1.25m/s, 1.75m/s. The walking performances were filmed by high speed video camera and EMG signal was gained by ME3000P8 Measurement Unit. Tibialis anterior(TA), Gastrocnemius medial head(GM), Gastrocnemius lateral head(GL), Ssoleus(SO) were selected for the dorsiflexion and plantarflexion of the ankle joint. The result of this study were as follows: 1. In the gait cycle, The time parameters for the phases were showed significant difference without the terminal stance phase and terminal swing phase for the different walking speed. 2. The angle of ankle joint was no significant difference for each time point and MDF, MPF but increasing walking speed the angle had the increasing pattern slightly. 3. The angular velocity of ankle joint was showed the significant difference for LHC, RTO, RKC, LHU, MPF and MDF point along the walking speed. 4. TA was showed about 2-3 times muscle activity at the 1.75m/s than 1.25m/s in some phases. And it was showed the similar muscle activity between the 0.75m/s and 1.25m/s but, showed a little much muscle activity in the 0.75m/s. GM was showed about 2-3 times muscle activity in the 1.75m/s than 1.25m/s, and even much muscle activity at the 0.75m/s than 1.25m/s in some phases. GL was showed increasing pattern of muscle activity specially in the initial swing phase as the walking speed increased. SO was showed about 3 times muscle activity in the 1.75m/s than 1.25m/s during the plantarflexion of ankle joint. It was showed the similar muscle activity between the 0.75m/s and 1.25m/s but, showed a little much muscle activity in the 1.25m/s.

• 한국운동역학회지
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• 제14권1호
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• pp.51-63
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• 2004

The purpose of this study was to investigate a three dimensional kinematic variables about the last stride and the release phase of the throwing technique for female javelin throwers. For the motion analysis, Six female javelin throwers were used as subjects. Three-dimensional coordinates were collected using the Kwon3D Motion Analysis Package Version 2.1 Program. Two S-VHS Video Cameras were used to record the locations and orientations of control object and the performances of the subjects at a frequency of 6.0 HZ. After the kinematic variables such as the time, the distance, the velocity, and the angle were analyzed about the last stride and release phase, the followings were achieved; 1. For the effectively javelin throwing, the subjects appeared to do long the approach time in the phasel of landing phase, and short the delivery time in release phase 2. In the release event, the other subjects except for subject A appeared to throwing in the lower condition than the height of themselves. This result showed to slow the projecion velocity. 3. For increase the projection vcelocity of the upper extremity joint in the release event, it appeared to do extend rather the shoulder angle than increase the extension of elbow joint. 4. The body of COG angle showed to gradually increase nearly at the vertical axis in the release event. But the front lean angle of trunk showed a small angle compare to increase of the body of COG angle. Therefore for the effectively momentum transmission of the whole body in the javelin, the front and back lean angle of trunk appeared to do fastly transfer the angle displacement in the arch posture or the crescent condition during the deliverly motion of the release phase.

• 한국운동역학회지
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• 제14권1호
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• pp.27-40
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• 2004

The purpose of this study was to provide basic data for improving athletic performances by analyzing the kinematic variables of the Double Backward Somersault on the Parallel Bars through the 3D motion analysis. The subjects in this study were 5 male gymnasts who were ranked as national athletes. The results are as follows. 1. A total time(Mean Time) of performance showed $2.72{\pm}0.82\;sec$. and flight time to landing after releasing was 0.87sec.(mean). In order to perform better stable flying movement, the flight time should be increased. 2. In the change of velocity of the center of mass, when the increasing ascension velocity of the upper point was high, the position in the top point was high on releasing. 3. In the position variable of the center of mass, the mean of upper-bottom position in horizontal posture was $242.1{\pm}6.5cm$, $232.8{\pm}6.4cm$ in releasing, and $265.0{\pm}5.6cm$ in the highest point. This result is explained that the position of center of mass can be raised by using elastic power when wrist raised the bar in the releasing movement. 4. The angle of shoulder joint was $271.1{\pm}14.0$. Such a big angle influences a negative effect on the releasing velocity, because trunk is not a position in the enough vertical direction. 5. The ankle of hip joint in hand-standing was $191.1{\pm}5.9$, $118.8{\pm}5.3$ in releasing, and $122.3{\pm}5.3$ in taking on. Therefore, the result suggests that trunk should be straightly raised in taking on.

• 제어로봇시스템학회논문지
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• 제17권10호
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• pp.1021-1028
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• 2011

The objective of this paper is to optimize the design parameters of a novel mechanism for a robotic knee orthosis. The feature of the proposed knee othosis is to drive a knee joint with independent actuation during swing and stance phases, which can allow an actuator with fast rotation to control swing motions and an actuator with high torque to control stance motions, respectively. The quadriceps device operates in five-bar links with 2-DOF motions during swing phase and is changed to six-bar links during stance phase by the contact motion to the patella device. The hamstring device operates in a slider-crank mechanism for entire gait cycle. The suggested kinematic model will allow a robotic knee orthosis to use compact and light actuators with full support during walking. However, the proposed orthosis must use additional linkages than a simple four-bar mechanism. To maximize the benefit of reducing the actuators power by using the developed kinematic design, it is necessary to minimize total weight of the device, while keeping necessary actuator performances of torques and angular velocities for support. In this paper, we use a SGA (Simple Genetic Algorithm) to minimize sum of total link lengths and motor power by reducing the weight of the novel knee orthosis. To find feasible parameters, kinematic constraints of the hamstring and quadriceps mechanisms have been applied to the algorithm. The proposed optimization scheme could reduce sum of total link lengths to half of the initial value. The proposed optimization scheme can be applied to reduce total weight of general multi-linkages while keeping necessary actuator specifications.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.464-469
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• 2001

This work provides the biomechanical evaluations of a manual wheelchair with a bi-directional driving system. The new propulsion strategy can be accomplished by employing a special gear system that converts the oscillatory motion of a handrim into the unidirectional output motion of a wheel. A main feature of the forward. backward propulsion is to supply continuous driving torque without break. Motion. analysis has been performed through 2-dimensional image processing for measuring the kinematic properties of the upper arm and fore arm. Then, the inverse dynamics analysis has been done for obtaining the joint torques, the handrim forces and input/output powers. Results show that the output power by the forward. reverse propulsion is almost twice as much as that by conventional propulsion. Also, the new propulsion is expected to reduce the fatigues and injuries at arm joints by employing more muscle groups for movement. In conclusion, the forward. reverse propulsion can greatly improve the performances of manual wheelchairs by providing better mobility as well as by guaranteeing several advantages from a biomechanical viewpoint. Future development of a manual wheelchair optimized for the bi-directional propulsion will further improve the propulsion performances.