• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.98-108
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• 2005

Conventional robot manipulators actuated by motors with the speed reducer such as the harmonic drive have weakness in the load capacity, since the speed reducer does not have enough strength. To improve this, a new type of robot actuator based on the four-bar-link mechanism driven by the ball screw was constructed. Also, a new type of revolute robot manipulator composed of the developed actuators was developed. But, modelling errors occur due to the off-set from the nominal model since the exact modeling of the complex inertia variation of the four-bar-link actuator is very difficult. To control the proposed robot along the prescribed trajectory, a sliding mode control algorithm was applied with compensation function for the modeling errors. To show performance of the proposed controller, a computer simulation was performed, and its results was presented.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.1
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• pp.84-91
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• 2002

A new composite control method for a carriage balancing single inverted pendulum system is proposed and applied to swing up the pendulum and to stabilize it under the state constraint. The target inverted pendulum system has an extremely limited length of the cart(below 16cm). The proposed swing-up controller comprises a sliding mode control algorithm and an optimal control algorithm based on two regions: the region near the inverted unstable equilibrium position and the rest of the state space including the downward stable equilibrium position. The sliding mode controller uses a switching control action to converge along the specified path(hyperplane) derived from energy equation from a state around the path to desired state(standing position). An optimal control method is also used to guarantee the stability at unstable equilibrium position. Compared with the reported controllers, it is simpler and easier to implement. Experimental results are given to show the effectiveness of this controller.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.402-406
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• 1990

A new approach of a time-varying switching hyperplane based on the theory of variable structure system (VSS) is proposed for the control of multivariable systems. While the conventional switching surface can net achieve the robust performance against parameter variations and disturbances before the sliding mode occurs, the proposed switching hyperplane, which is obtained from the eigen-structure assignment theory powerfully used in the linear multivariable systems, ensures the sliding mode from the initial state. And new continuous control input which guarantees the sliding mode is proposed. This new control input does not arise chattering problem which arises with the conventional control input of variable structure control systems. Through numerical examples, the expellant performances of the proposed controller are verified.

• Journal of Power System Engineering
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• v.18 no.5
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• pp.129-136
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• 2014

This paper proposes improvement on sensorless vector control performance of a permanent magnet synchronous motor (PMSM) with sliding mode observer. An adaptive observer gain and second order cascade low-pass filter (LPF) were used to improve the estimation accuracy of the rotor position and speed. The adaptive observer gain was applied to suppress the chattering intensity and obtained by using the Lyapunov's stability criterion. The second order cascade LPF was designed for the system to escalate the filtering performance of the back-emf estimation. Furthermore, genetic algorithm was used to optimize the system PI controller's performance. Simulation results showed the effectiveness of the suggested improvement strategy. Moreover, the strategy was useful for the sensorless vector control of PMSM to operate on the low-speed area.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.157-161
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• 1992

Up to now, there has been a lot of researches on the sliding mode control which has the insensitive characteristics to the variations of plant parameters, nonlinearities and external disturbances. One dificulty in applying the sliding mode control is the need for the knowledge of the full-state vector. The use of state observer is a natural step towards the relaxation of this condition. However, the exact plant-modeling is assumed to be known. Recently, there has been a remarkable advance in the microprocessor and one can construct the controller which could not realize due to hardware restriction in the past. Therefore in this paper, the PID sliding mode controller which has only one output feedback signal is suggested by means of microprocessor and the performance of electro-hydraulic servosystem compersated with this controller is proved.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2525-2527
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• 2002

The objective of this paper is to design a force feedback controller for bilateral control of a master-slave manipulator system using adaptive fuzzy sliding mode control. In a bilateral control system, the motion of the master device is followed by slave the one. While the force applied to the slave is reflected on the master. In this paper a proposed controller applied to the system. Adding a switching control term to the input robustness is improved. Also the knowledge of the system dynamics is not needed. The computer simulation results show the performance of the proposed adaptive fuzzy sliding mode controller.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2380-2382
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• 2001

The objective of this paper is to design a force feedback controller for bilateral control of a master-slave manipulator system using fuzzy sliding mode control. In a bilateral control system the motion of the master device is followed by slave the one. While the force applied to the slave is reflected on the master. In this paper, a proposed controller applied to the system. Adding a switching control term to the input, robustness is improved. Also the knowledge of the system dynamics is not needed. The computer simulation results show the performance of the proposed fuzzy sliding mode controller.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.1
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• pp.90-98
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• 2012

In this paper, the Integrated Guidance and Control (IGC) law is proposed for the Rotary Unmanned Aerial Vehicle (RUAV). The objective of the IGC law is to consider the nonlinear dynamic characteristics of the RUAV and to design a guidance law which takes into consideration the nonlinear relationship between kinematics and dynamics. In order to control the RUAV system, sliding mode control scheme is adopted. As the RUAV is an under-actuated system, a slack variable approach is used to generate the available control inputs. Through the Lyapunov stability theorem, the stability of the proposed IGC law is proved. In order to verify the performance of the IGC law, numerical simulations are performed for waypoint tracking missions.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.43-49
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• 2003

The common-rail fuel injection system is becoming a common technology for High Speed Direct Injection(HSDI) diesel engines. The injection timing and rate are important factors for combustion control and pollutants formation mechanisms during engine operation. This paper introduces an estimation methodology of the injection timing and rate of a common-rail injector for HSDI diesel engines. A sliding mode observer that is based on the nonlinear mathematical model of the common-rail injector is designed to overcome the model uncertainties. The injector model and the estimator we verified by relevant injection experiments in an injector test bench. The simulation and the experimental results show that the proposed sliding mode observer can effectively estimate the injection rate of the common-rail injector.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.893-898
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• 2003

Coulomb friction is an important factor for precise position tracking control systems. The control systems with friction causes the steady state error because of being sensitive to the change of system condition and highly nonlinear characteristics. To overcome these problems, we use an estimation scheme of Coulomb friction to experiment for it's compensating. The estimated factor for Coulomb friction is used as a feed-forward compensator to improve the tracking performance of ball-screw systems. The tracking performance was improved by compensating the estimated friction torque in the feed-forward term. And, the sliding mode control which is derived from the Lyapunov stability theorem is applied for robust stability and reducing chattering. The experimental results show that the sliding mode controller with adaptive friction compensator has a good tracking performance compared with the friction uncompensated controller.