• Proceedings of the KIEE Conference
• /
• 1993.07a
• /
• pp.359-361
• /
• 1993

In this paper, a variable structure controller with time-varying sliding surface is proposed for robot manipulators. The proposed time-varying sliding surface ensures the existence of sliding mode from an initial state, while the contentional sliding surface cannot achieve the robust performance against parameter variations and disturbances before the sliding mode occurs. Therefore, error transient can be fully prescribed in advance for all time. Furthermore, it is shown that the overall system is globally exponetially stable. The efficiency of the proposed method for the trajectory tracking has been demonstrated by simulations.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.62.2-62
• /
• 2001

In this paper, we present a new time-varying sliding mode system that guarantees stable error convergence. The previous papers have dealt with stability of the time-varying sliding mode system by point-wisely investigating the stability of time-invariant system every time. However, it may be unstable even though it guarantees time-invariant stability every time, We designed the time-varying sliding surface so that the resultant time-varying system on sliding mode may be Stable. The initial sliding surface is obtained so that shifting distance of the surface may be minimized with respect to an initial error, and the intercept is produced so that the surface may pass the initial error.

• Journal of Institute of Control, Robotics and Systems
• /
• v.5 no.4
• /
• pp.379-384
• /
• 1999

In this paper, we present a new time-varying sliding surface to achieve fast and robust tracking of higher-order uncertain systems. The surface passes through an initial error, and afterwards, it moves towards a predetermined target surface by means of a variable named by sliding surface gain and its intercept. Specifically, the sliding surface gain is determined so that its initial value can minimize a shifting distance of the surface and that the system roots in sliding mode can follow certain stable trajectories. The designed sliding mode control forces the system errors to stay always on the proposed surface from the beginning. By this means, the system remains insensitive to system uncertainties and disturbances for the whole time. To illustrate the effectiveness of the proposed method, the comparative study with conventional time-invariant sliding mode control is performed.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2000.05a
• /
• pp.51-54
• /
• 2000

In variable structure control algorithm, sliding mode makes the closed loop system insensitive to modelling uncertainties and external disturbances. However due to imperfections in switching, the system trajectory chatters, which is very undesirable. And the insensitivity property of a sliding mode controller is present only when the system is in the sliding mode. To overcome these shortcomings, in this paper, new sliding mode control algorithm using time-varying sliding surface and fuzzy PI structrue is proposed.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.771-774
• /
• 1996

This paper presents a continuous time varying sliding surface that allows faster tracking and really guarantees robust contro land smooths control inputs. And this method is evaluated by applying to robot manipulator.

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.12
• /
• pp.1197-1200
• /
• 2010

The problem of designing a nonlinear sliding surface for an uncertain system is considered. The proposed sliding surface comprises a linear time invariant term and an additional time varying nonlinear term. It is assumed that a linear sliding surface parameter matrix guaranteeing the asymptotic stability of the sliding mode dynamics is given. The linear sliding surface parameter matrix is used for the linear term of the proposed sliding surface. The additional nonlinear term is designed so that a Lyapunov function decreases more rapidly. By including the additional nonlinear term to the linear sliding surface parameter matrix we obtain a nonlinear sliding surface such that the speed of responses is improved. We also give a switching feedback control law inducing a stable sliding motion in finite time. Finally, we give an LMI-based design algorithm, together with a design example.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.253-256
• /
• 1996

In this paper, A new time-varying sliding surface design using eigenvalue locus is proposed to achieve fast and robust in a class of high-order uncertain dynamic system. A moving sliding surface(MSS) was proposed earlier for the second-order variable structure control systems(VSCS). This methodology led to fast and robust control responses of the second-order VSCS. However, the moving algorithm of the MSS was too complicated to be employed the high-order VSCS. To resolve this problem, we propose a new moving algorithm that switching surface moves such that the eigenvalues of equivalent system in the sliding mode have a predetermined locus. Using the proposed surface fast and robust behaviors are accomplished. The problem of chattering can be eliminated by using a boundary layer of switching surface. The efficiency of proposed algorithm is illustrated by an application to four-order workbench.

• Journal of Institute of Control, Robotics and Systems
• /
• v.1 no.2
• /
• pp.99-104
• /
• 1995

For the robust control, sliding mode control has gained a great attention. Sliding mode control has the good robustness, because it makes the state of system reach the origin of the state space, by a varying the structure of system on the sliding surface. The slope of sliding surface affects to the control performance. If it is small, robustness is increased at the expense of reaching time. On the contrary, if it is large, reaching time is decreased at the expense of robustness and overshoot. In this paper, to design the optimal sliding surface, optimal control theory is introduced. To confirm the validity of the proposed method, the position control of step motor is implemented.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.61.2-61
• /
• 2002

$\textbullet$ Introduction $\textbullet$ Dynamics of robotic manipulator $\textbullet$ Time-varying sliding surface $\textbullet$ Fuzzy rule, Membership function $\textbullet$ Application to a two degree robotic manipulator $\textbullet$ Conclusion

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.5
• /
• pp.666-672
• /
• 2003

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 condition and be robust to the parameter uncertainties in the plant model. Control performance is evaluated from the simulation for the vehicle of real parameters on the road with various tire-road frictions.