• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1644-1645
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• 2007

This paper proposes an adaptive sliding mode control method for trajectory tracking of nonholonomic mobile robots with model uncertainties and external disturbances. The kinematic model represented by polar coordinates are considered to design a robust control system. Wavelet neural networks (WNNs) are employed to approximate arbitrary model uncertainties in dynamics of the mobile robot. From the Lyapunov stability theory, we derive tuning algorithms for all weights of WNNs and prove that all signals of an adaptive closed-loop system are uniformly ultimately bounded.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.353-368
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• 2023

The four wing unmanned aerial vehicle owns the characteristics of small size, light weight, convenient operation and well stability. But it is easily disturbed by external environmental factors during flight with these disadvantages of short endurance and poor attitude solving ability. For solving these problems, a microprocessor based on STM32 chip is designed and the overall development is completed by the resources such as built-in timer and multi-function mode general-purpose input/output provided by the master micro controller unit, together with radio receiver, attitude meter, barometer, electronic speed control and other devices. The unmanned aerial vehicle can be remotely controlled and send radio waves to its corresponding receiver, control the analog level change of its corresponding channel pins. The master control chip can analyze and process the data to send multiple sets pulse signals of pulse width modulation to each electronic speed control. Then the electronic speed control will transform different pulse signals into different sizes of current value to drive the motor located in each direction of the frame to generate different rotational speed and generate lift force. To control the body of the unmanned aerial vehicle, so as to achieve the operator's requirements for attitude control, the PID controller based on Kalman filter is used to achieve quick response time and control accuracy. Test results show that the design is feasible.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.162-167
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• 2004

In this research the Co-simulation technique for an electric power steering system with MATLAB/SIMULINK and a full vehicle model with ADAMS has been developed. The dynamic responses of vehicle chassis and steering system are evaluated. Then, a full vehicle model interacted with EPS control is concurrently simulated with an impulsive steering wheel torque input to analyze the stability of 'free control' or hands free motion for Sports Utility Vehicle. This integrated method allows engineers to reduce the prototype testing cost and to shorten the developing period.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1843-1850
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• 2015

Controlling nonlinear systems with linear feedback control methods can lead to chaotic behaviors. Order increase in system dynamics due to integral control and control parameter variations in PID controlled nonlinear systems are studied for possible chaos regions in the closed-loop system dynamics. The Lur’e form of the feedback systems are analyzed with Routh’s stability criterion and describing function analysis for chaos prediction. Several novel chaotic systems are generated from second-order nonlinear systems including the simplest continuous-time chaotic system. Analytical and numerical results are provided to verify the existence of the chaotic dynamics.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.12
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• pp.995-1001
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• 2016

The vehicle suspension system plays a very important part related with vehicle ride and handling. To improve the vehicle ride and handling many researches have been progressed from various damping parameter tuning techniques to the development of the electronic controlled suspension systems. In this paper, as one of the ride performance improvement a disturbance observer(DOB) based control system is applied to the quarter car vehicle model in order to show that the DOB can obtain good vibration isolation characteristics. First, the robust stability criterion for the DOB is introduced in detail, and then how DOB is applied to the 1/4 car vehicle model is represented, and finally to confirm the effectiveness of the DOB in vehicle ride performance improvement a computer simulation is carried out for various driving conditions.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.3
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• pp.211-216
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• 2009

Chattering phenomenon is still a large drawback of VSS. To overcome this problem, various approaches have been reported. A new notion of sliding sector has been proposed recently. In this paper, fuzzy control with time-varying boundary layer using the sliding sector theory with continued input function in the sector is proposed. This paper analyzes the stability, using Lyapunov function on the sliding sector. Computer simulation for inverted pendulum results in elimination of the chattering phenomenon.

• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.3
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• pp.168-173
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• 2007

Chattering phenomenon is still a large drawback of VSS. To overcome this problem, various approaches have been reported. A new notion of sliding sector has been proposed recently. In this paper, new methods of the nonlinear system control using the sliding sector theory with continued input function in the sector is proposed. This paper analyzes the stability, using Lyapunov function on the sliding sector. computer simulation for inverted pendulum results in elimination of the chattering phenomenon.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.4
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• pp.240-246
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• 2018

In this paper, a sensorless V/f control based on maximum torque per ampere (MTPA) operation for PMSMs is proposed. Given that the MTPA operation is not considered in the conventional sensorless V/f control, efficient PMSM drives cannot be achieved. Therefore, this paper proposes an improved technique based on the d-axis current control to enable the MTPA operation in the V/f control for PMSMs. A stabilization technique is also proposed to improve the dynamic characteristics and stability against load variation. The effectiveness of the proposed technique is verified by conducting experiments with a 250 W SPMSM for driving a blower.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.502-507
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• 2016

In this paper, we propose a tracking control method for a quadrotor equipped with a 2-DOF manipulator, which is based on the multiple sliding surface control (MSSC) method. To derive the model of a quadrotor equipped with a 2-DOF manipulator, we obtain the models of a quadrotor and a 2-DOF manipulator based on the Lagrange-Euler formulation separately - and include the inertia and the reactive torque generated by a manipulator when these obtained models are combined. To make a quadrotor equipped with a manipulator track the desired path, we design a double-loop controller. The desired position is converted into the desired angular position in the outer controller and the system's angle tracks the desired angular position through the inner controller based on the MSSC method. We prove that the position-tracking error asymptotically converges to zero based on the Lyapunov stability theory. Finally, we demonstrate the effectiveness of the proposed control system through a computer simulation.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.1
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• pp.57-65
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• 2017

This paper presented a method of designing low-power feedback active noise control filter optimized for headphones/earphones. Using constrained optimization, we obtained a high order FIR noise control filter to ensure reasonable noise attenuation performance at high sampling frequency environment. Then using infinite impulse response (IIR) approximation method called Balanced Model Truncation (BMT), we obtained a low order IIR noise control filter suitable for low-power digital signal processing system like headphones/earphones. For further performance improvement, we utilized frequency warping method so that we could obtain more accurately approximated IIR filter and we ensured system stability by reconstructing the low order IIR filter in form of cascaded second order IIR filters. ANC simulation with white noise and stability test verified that the proposed algorithm had superior attenuation performance and better robustness compared to the conventional algorithm.