• Coupled systems mechanics
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• v.7 no.6
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• pp.707-729
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• 2018

The semi-active optimal vibration control of nonlinear torsion-bar suspension vehicle systems under random road excitations is an important research subject, and the boundedness of MR dampers and the uncertainty of vehicle systems are necessary to consider. In this paper, the differential equations of motion of the coupling torsion-bar suspension vehicle system with MR damper under random road excitation are derived and then transformed into strongly nonlinear stochastic coupling vibration equations. The dynamical programming equation is derived based on the stochastic dynamical programming principle firstly for the nonlinear stochastic system. The semi-active bounded parametric optimal control law is determined by the programming equation and MR damper dynamics. Then for the uncertain nonlinear stochastic system, the minimax dynamical programming equation is derived based on the minimax stochastic dynamical programming principle. The worst-case disturbances and corresponding semi-active bounded parametric optimal control are obtained from the programming equation under the bounded disturbance constraints and MR damper dynamics. The control strategy for the nonlinear stochastic vibration of the uncertain torsion-bar suspension vehicle system is developed. The good effectiveness of the proposed control is illustrated with numerical results. The control performances for the vehicle system with different bounds of MR damper under different vehicle speeds and random road excitations are discussed.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.2
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• pp.83-90
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• 1994

The container crane is still operated by skillfull human operators. So an automatic crane operation system is strongly required. In this paper, the digital control method is applied to position an anti-swing control for container crane. Two methods of digital optimal regulator control and digital redesign control are used for experiment. From these experimental results, it is respected that both methods can be applied effectively to an actual container crane operation.

• International Journal of Air-Conditioning and Refrigeration
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• v.14 no.4
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• pp.138-146
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• 2006

Recently, a technology based on the proportional integral (PI) control have grown rapidly owing to the needs for the robust capacity of the controllers from industrial building sectors. However, PI controller generally requires tuning of gains for optimal control when the outside weather condition changes. The present study presents the possibility of reinforcement learning (RL) control algorithm with PI controller adapted in the HVAC system. The optimal design criteria of RL controller was proposed in the environment chamber experiment and a theoretical analysis was also conducted using TRNSYS program.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.231-244
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• 2007

In this paper, we use measure theory for considering asymptotically stable of an autonomous system [1] of first order nonlinear ordinary differential equations(ODE's). First, we define a nonlinear infinite-horizon optimal control problem related to the ODE. Then, by a suitable change of variable, we transform the problem to a finite-horizon nonlinear optimal control problem. Then, the problem is modified into one consisting of the minimization of a linear functional over a set of positive Radon measures. The optimal measure is approximated by a finite combination of atomic measures and the problem converted to a finite-dimensional linear programming problem. The solution to this linear programming problem is used to find a piecewise-constant control, and by using the approximated control signals, we obtain the approximate trajectories and the error functional related to it. Finally the approximated trajectories and error functional is used to for considering asymptotically stable of the original problem.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.698-706
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• 2016

In order to move mobile robots to desired locations in a minimum time, optimal control problems have to be solved; however, their analytic solutions are almost impossible to obtain due to robot nonlinear equations. This paper presents a method to get optimal control gains of mobile robots using genetic algorithms. Since the optimal control gains of mobile robots depend on the initial conditions, the initial condition range is discretized to form some grid points, and genetic algorithms are applied to provide the optimal control gains for the corresponding grid points. The optimal control gains for general initial conditions may be obtained by use of neural networks. So the optimal control gains and the corresponding grid points are used to train neural networks. The trained neural networks can supply pseudo-optimal control gains. Finally simulation studies have been conducted to verify the effectiveness of the method presented in this paper.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.1
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• pp.29-34
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• 1989

Recently microcomputers have come into wide use in the field of the control. They are used not only as monitors and as controllers in the various plant control systems but also as the Computer Aided Design of control systems. As an example of the design and the realtime control of the control system using Microcomputer, the optimal design of the control system of which the numerator of the transfer function is constant have been reported by authors. In this paper, author proposes a method to design the optimal controller about the control system of which the numerator of the transfer function is not constant, and develops the program of the response simulation.

• Journal of Nutrition and Health
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• v.16 no.1
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• pp.21-26
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• 1983

For the purpose of study on optimal gustation of salt 108 patients with hypertension(61 cases of male, 47 cases of female) were studied. And also 48 patients with non-hypertensive heart diseases and pulmonary diseases (20 cases of male, 28 cases of female ) and apparently healthy subjects (107 cases of male, 20 cases of female) were studied as control group. By adding salt into 3% rice boiled powder solution the 0.1%, 0.25% 0.5%, 0.75% and 1 % salt solutions were prepared respectively. Allowed subject to taste all above solution in landed and to point out the optimal salty taste of each subject. There were no significant difference in optimal gustation of salt among the hypertensive patients and control group. The optimal salt gustation of hypertensive patients with low salt diet was slightly lower than those with free diet The optimal salt gustation was higher in old aged persons regardless of diseases.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.5
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• pp.1148-1160
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• 2001

An electronic control system of the automobile engine for optimal start and idle speed control has been developed. This system employs the microcoputer-based electronic control unit and crank angle sensor for precise control on fuel injection, ignition timing, and idle speed more quickly and accurately at the start and idling. Consequently, the number of misfire can be reduced during been affected by air flow rate, idle quality(roughness), spark timing, fuel injection, water temperature, and load, Thus, this electronic control system strivers to reach the optimal idle operating point, defined the lowest idle speed(fuel economy) and idle quality(roughness), under any engine operating conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.2
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• pp.30-37
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• 2012

Pneumatic Active Engine Mount(PAEM) with open-loop control system has been developed to reduce the transmission of the idle-shake vibration induced by engine effectively and economically. A solenoid valve installed between PAEM and vacuum tank is on-off switched by the Pulse Width Modulate(PWM) control signal to decrease the dynamic stiffness of the engine mount. This paper presents the methodology to identify the optimal values of control parameters of a PAEM, i.e, turn-on timing and duty ratio of PWM signal for 6 different idle driving conditions. A scanning algorithm was first applied to the vehicle test to obtain the approximate optimal control parameters minimizing the vibration at front seat rail and at steering wheel. Then the PAEM system identification was fulfilled to find accurate optimal control parameters by using multi-layer neural networks of Levenberg-Marquardt algorithm with vehicle test data.

• Journal of Ocean Engineering and Technology
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• v.19 no.1 s.62
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• pp.87-94
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• 2005

This paper investigates the constant-level luffing and time optimal control of jib cranes. The constant-level luffing, which is the sustainment of the load at a constant height during luffing, is achieved by analyzing the kinematic relationship between the angular displacement of a boom and that of the main hoist motor of a jib crane. Under the assumption that the main body of the crane does not rotate, the equations of motion of the boom are derived using Newton's Second Law. The dynamic equations for the crane system are highly nonlinear; therefore, they are linearized under the small angular motion of the load to apply linear control theory. This paper investigates the time optimal control from the perspective of no-sway at a target point. A stepped velocity pattern is used to design the moving path of the jib crane. Simulation results demonstrate the effectiveness of the time optimal control, in terms of anti-sway motion of the load, while luffing the crane.