• Physical Therapy Korea
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• v.15 no.1
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• pp.30-37
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• 2008

This study was designed to examine the effects of temporary immobilization of the ankle and knee joints on standing in healthy young adults with the use of a postural control mechanism. The subjects were twenty-four college students (12 males and 12 females, aged between 20 and 28). A Biodex balance system SD 950-302 and its software were used to measure indirect balance parameters in standing. Each subject underwent postural stability tests in 4-different joint conditions: free joints, ankle immobilization only, knee immobilization only, and ankle and knee immobilization. In addition, the postural stability test was conducted once with the subject's eyes open and once with the eyes closed conditions. For data analysis of the postural stability tests, the overall stability index, antero-posterior stability index, and medio-lateral stability index were recorded. The overall stability index (p=.000) and medial-lateral index (p=.003) were significantly greater different conditions with eyes closed in postural stability. Therefore, the eyes closed condition is expected to be used as an effective postural stability training for treatment planning in patients with unstable postures. In addition, training based on the dynamic multi-segment model can improve postural stability and is available to therapeutic programs, helping people with unstable balance to reduce their risk of falling.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.112-112
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• 2000

The aim of this paper is to design a two degree-of-freedom H$_{\infty}$ controller for lateral control of the vehicle. The object of this controller is to track the centerline of the reference lane. The controller is splited into two parts, feedback and prefilter. The feedback part is for both robust stability and disturbance attenuation, while the prefilter is for improving the robust tracking properties of closed loop system. This paper is consist of preface, background theory, dynamics of vehicle, controller design and computer simulation.ter simulation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.12 s.255
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• pp.1551-1556
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• 2006

Two yaw motion control systems that improve a vehicle lateral stability are proposed in this study: a rear wheel steering yaw motion controller (SESP) and an enhanced rear wheel steering yaw motion controller (ESESP). A SESP controls the rear wheels, while an ESESP steers the rear wheels and front outer wheel to allow the yaw rate to track the reference yaw rate. A 15 degree-of-freedom vehicle model, simplified steering system model, and driver model are used to evaluate the proposed SESP and ESESP. A robust anti-lock braking system (ABS) controller is also designed and developed. The performance of the SESP and ESESP are evaluated under various road conditions and driving inputs. They reduce the slip angle when braking and steering inputs are applied simultaneously, thereby increasing the controllability and stability of the vehicle on slippery roads.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.619-623
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• 1993

In this paper, a neural network is appled to design a lateral autopilot for airplanes. Linearized lateral dynamics is used in training the neural network controller and verifying the performance as well. To train the neural network, back propagation algorithm is used. In this training, no information about the dynamics to be controlled except sign and rough magnitude of control derivatives is needed. It is shown by computer simulations that the performance and stability margin are satisfactory.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.209-217
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• 2013

This paper presents a control strategy of 4 wheel drive (4WD) vehicles. Proposed control strategy has simple structure and can easily apply to various vehicles with low cost and time. It is consist of feedforward control for traction ability, fedback control for minimizing the wheel speed difference and yaw control for lateral stability. In addition, to integrate the traction and stability control, a blending function is applied. To evaluate the feasibility of the proposed control strategy, actual vehicle experiment is conducted after deciding the tuning parameter through the simulation. The simulation is accomplished by CarSim and Matlab/Simulink and the actual vehicle test is conducted using full size Sports Utility Vehicle (SUV) equipped rear wheel based solenoid type 4WD device.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.11
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• pp.913-919
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• 2005

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modem version supersonic jet fighter aircraft. The flight control system utilizes RSS criteria in both longitudinal and lateral-directional axes to achieve performance enhancements and improve stability. Standard CLDA (Control Law Design and Analysis) process is provided that reduce the development period of the flight control system. In addition, if this process is employed in developing flight control laws, it reduces the trial and error development and verification of control laws. This paper details the design process of developing a flight control law for the RSS aircraft, utilizing military specifications, linear and nonlinea, analysis using XMATH and ATLAS(Aircraft, Tim Linear and Simulation), handling quality tests using the HQS (Handling Quality Simulator), and real flight test results to verify aircraft dynamic flight responses.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.195-201
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• 2005

In conventional Vehicle Stability Control (VSC) System, a control threshold is designed by average driver characteristics. Despite the stabilizing effort, VSC causes redundancy to an expert driver. An advanced VSC which has flexibility on its control property is proposed in this study. By using lateral velocity estimator, a control threshold is determined on side slip angle and angular velocity phase plane. Vehicle planar motion model based sliding controller is modified with respect to various control thresholds. The performance of the proposed VSC algorithm has been investigated by human-in-the-loop simulation using a vehicle simulator. The simulation results show that the control threshold has to be determined with respect to the driver steering characteristics. A VSC with variable control thresholds would provide an improvement compared to a VSC with a constant threshold.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.458-463
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• 2000

This paper presents a design of the controller for vehicle lateral dynamics using active yaw moment. Vehicle lateral motion is incorporated with directional controllability and stability. These are conflicting each other from the view of vehicle handling performance. To compromise the trade-off between these two aspects, we suggest a new control algorithm based on the sliding mode with time-varying switching surface according to the body side slip angle. The controller can deal with the nonlinear region in vehicle driving and be robust to the parameter uncertainties in the plant model. Control performance was evaluated from the simulation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.12
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• pp.2519-2526
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• 2002

A disturbance observer-based vehicle stability controller is proposed in this paper. The lumped disturbance to the vehicle yaw rate dynamics caused by the uncertain factors such as uncertain tire forces and parameters is estimated by the disturbance observer, which is utilized by the robust controller to stabilize the lateral dynamics of the vehicle. The dynamics of the hydraulic actuator is incorporated in the vehicle stability controller design using the model reduction technique. Modular control design methodology is adopted to effectively deal with the mismatched uncertainty. Simulation results indicate that the proposed disturbance observer-based vehicle stability controller can achieve the desired reference tracking performance as well as sufficient level of robustness.

• Journal of Auto-vehicle Safety Association
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• v.5 no.1
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• pp.62-68
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• 2013

This paper describes development of 4 Wheel Drive (4WD) Electric Vehicle (EV) based driving control algorithm for severe driving situation such as icy road or disturbance. The proposed control algorithm consists three parts : a supervisory controller, an upper-level controller and optimal torque vectoring controller. The supervisory controller determines desired dynamics with cornering stiffness estimator using recursive least square. The upper-level controller determines longitudinal force and yaw moment using sliding mode control. The yaw moment, particularly, is calculated by integration of a side-slip angle and yaw rate for the performance and robustness benefits. The optimal torque vectoring controller determines the optimal torques each wheel using control allocation method. The numerical simulation studies have been conducted to evaluated the proposed driving control algorithm. It has been shown from simulation studies that vehicle maneuverability and lateral stability performance can be significantly improved by the proposed driving controller in severe driving situations.