• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.3
• /
• pp.228-235
• /
• 2010

This paper deals with an autonomous flight controller design problem for a tilt-rotor aircraft in rotary-wing mode. The inner-loop algorithm is designed using the output-based approximate feedback linearization. The model error originated from the feedback linearization is cancelled within allowable tolerance by using single-hidden-layer neural network. According to Lyapunov direct stability theory, the adaptive update law is derived to run the neural network on-line, which is based on the linear observer dynamics. Moreover, the outer-loop algorithm is designed to track the trajectory generated from way-point guidance. Especially, heading and flight-path angle line-of-sight guidance are applied to the outer-loop to improve accuracy of the landing tracking performance. The 6-DOF nonlinear simulation shows that the overall performance of the flight control algorithm is satisfactory even though the collective input response shows instantaneous actuator saturation for a short time due to the lack of the neural network and the saturation protection logic in that loop.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.4 no.1
• /
• pp.1-12
• /
• 1999

A design and DSP-based implementation of robust nonlinear speed control of a permanent magnet synchronous motor(PMSM) under the unknown parameter variations and speed measurement error is presented. The model reference adaptive system(MRAS) based adaptation mechanisms for the estimation of slowly varying parameters are derived using the MIT rule. For the disturbances or quickly varying parameters, a quasilinearized and decoupled model which includes the influence of parameter variations and speed measurement error on the nonlinear speed control of a PMSM is derived. Based on this model, a boundary layer integral sliding mode controller to improve the robustness and performance of the nonlinear speed control of a PMSM is designed and compared with the conventional controller which employs Proportional plus Derivative(PD) control. To show the validity of the proposed scheme, simulations and DSP-based experimental works are carried out and compared with the conventional control scheme.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.3
• /
• pp.62-68
• /
• 2006

In this paper, an adaptive input-output linearization and zero dynamics control of three phase AC/DC converter are proposed. For achieving output do voltage regulation with unity power factor, the q-axis current of the rotating d-q frame is regulated to zero and the output do voltage is controlled to track a given reference voltage $V_r$. The proposed scheme is robust to the parametric uncertainty md load current of the converter due to the adaptation process. The simulation results are presented to illustrate the performance and feasibility of the proposed control scheme.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.39 no.1
• /
• pp.36-48
• /
• 1990

A new control method for robust position control of brushless dc motor is presented. The model of brushless dc motor is approximately linearized by field-orentation method, and it is shown that augmented state variable feedback can be applied to this system. In addition, robustness is obtained without any change of overall system response. Load disturbance is detected by 0-observer of unknown and inaccessible input, and is compensated by feedforward which has fast response. Overall system is controlled by using the MC68000 microprocessor, and the performance of the proposed control algorithm is verified by the results of simulation and experiment.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.12 no.2
• /
• pp.131-138
• /
• 2007

In this paper, a novel nonlinear control method of the CVCF(constant voltage and constant frequency) output voltage for the three-phase PWM inverter with LC output filters is proposed. A nonlinear modeling including the output LC filters is linearized by feedback linearization theory, the controllers of which can be designed based on a linear control theory. It is applied to the DC/AC power conversion of the PWM inverter for stand-alone wind power generation system. It has been verified by the experimental results that the proposed control scheme gives high dynamic responses at load variation as well as a zero steady-state error.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.6
• /
• pp.505-511
• /
• 2015

Solid oxide fuel cell operate at high temperature ($800{\sim}1000^{\circ}C$). High temperature have an advantage of system efficiency, but a weak durability. In this study, linear state space controller is designed to handle the temperature of solid oxide fuel cell system for proper thermal management. System model is developed under simulink environment with Thermolib$^{(R)}$. Since the thermally optimal system integration improves efficiency, very complicated thermal integration approach is selected for system integration. It shows that temperature response of fuel cell stack and catalytic burner are operated at severe non-linearity. To control non-linear temperature response of SOFC system, gain scheduled linear quadratic regulator is designed. Results shows that the temperature response of stack and catalytic burner follows the command over whole ranges of operations.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.18 no.4
• /
• pp.333-341
• /
• 2013

In this paper, a feedback linearization control is proposed to regulate the output voltages of a three-phase four-wire inverter under the unbalanced and nonlinear load conditions. First, the nonlinear model of system including the output LC filters is derived in the d-q-0 synchronous reference frame. Then, the system is linearized by the multi-input multi-output feedback linearization. The tracking controllers for d-q-0-components of three-phase line-to-neutral load voltages are designed by linear control theory. The experimental results have shown that the proposed control method gives the good performance in response to the load conditions.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.1
• /
• pp.121-127
• /
• 2010

We consider the robust trajectory tracking control problem for a skid steering mobile robots. A dynamic model is derived accounting for the effects of wheel skidding. The control design utilizes the dynamic feedback linearization techniques, so as to obtain a predictable behavior for the instantaneous center of rotation thus preventing excessive skidding. The additive controller using the sliding mode type is then robustified against the unmodelled dynamics and parameter uncertainty. Simulation results show the good performances under excessively uncorrected estimations of the longitudinal forces and the lateral resistive forces caused by the skidding of the wheels in tracking trajectories.

• Proceedings of the KIEE Conference
• /
• 1991.11a
• /
• pp.366-369
• /
• 1991

A nonlinear controller based on feedback linearization method is proposed for an electromagnetic suspension system. After exactly linearizing the system with nonlinear feedback, linear control technique is applied. Modeling of stagger typed magnet is introduced and controlled for not only levitation, but guidance. By the feedback linearization, the nonlinear, MIMO system is linearized and decoupled, so we can use linear control law. The simulation of this system control skim is demonstrated. Robustness properties of the proposed controller with respect to the load variations and external disturbance is also analyzed for a multi input multi output system. In this properties, the boundary of variation is proposed.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.672-674
• /
• 2004

Many nonlinear controllers for the power system are based on nonlinear models involving the power angle as an element of the state, and therefore the reference value for the power angle is needed. As this reference value is not generally available, it is difficult to apply such nonlinear control methods in practice. To deal with this problem, we present an input-output feedback linearizing control scheme by selecting the output as a combination of the squared voltage and the relative frequency. It is shown that the internal dynamics are locally stable with controllable damping, and that the frequency remains bounded for all time. Simulations illustrate the effectiveness of the proposed method.