Woonchul Ham

Adaptive fuzzy sliding mode control of nonlinear system

In this paper, the fuzzy approximator and sliding mode control (SMC) scheme are considered. We propose two methods of adaptive SMC schemes that the fuzzy logic systems (approximators) are used to approximate the unknown system functions in designing the SMC of nonlinear system. In the first method, a fuzzy logic system is utilized to approximate the unknown function f of the nonlinear system x/sup n=/f(x, t)+b(x, t)u and the robust adaptive law is proposed to reduce the approximation errors between the true nonlinear functions and fuzzy approximators. In the second method, two fuzzy logic systems are utilized to approximate the f and b, respectively, and the control law, which is robust to approximation error is also designed. The stabilities of proposed control schemes are proved and these schemes are applied to an inverted pendulum system. The comparisons between the proposed control schemes are shown in simulations.

Self stabilizing strategy in tracking control of unmanned electric bicycle with mass balance

Ingyu Park et al. (2001) investigated an unmanned bicycle system but did not consider the lateral motion of mass. In this paper, we derive a simple kinematic and dynamic formulation of an unmanned electric bicycle with load mass balance system which, plays important role in stabilization. We propose a control algorithm for the self stabilization of unmanned bicycle by using nonlinear control based on the sliding patch and stuck phenomena. In deriving the above control algorithm, we assume that the load mass is located in the middle of the mass balance system. We then propose a control strategy to turn the bicycle system left or right by moving the center of load mass left and right respectively. In the computer simulations, we adopt a low pass filter for the real implementation of the proposed control law which bring. about the chattering problem. From the computer simulation results, we can show the effectiveness of the proposed control strategy.

Adaptive control based on explicit model of robot manipulator

Adaptive and nonadaptive control algorithms, which make use of a fundamental mathematical property concerning positive definite matrices and Lyapunov stability theory, are proposed for the control of robot manipulators. Using the fact that the matrix dD(q)/dt-2C(q, dq/dt) is skew symmetric, nonadaptive controllers which have a simplified structure with less computational burden are proposed. Using the dynamic equations for robot manipulators, parameter adaptation rules are developed for updating the controllers partially or totally unknown parameters, generalizing them to model reference adaptive controllers. To further take advantage of the simplified structure of the proposed adaptive controllers, a method for deriving the dynamic model of a robot manipulator which is linear in terms of its parameters is given. This dynamic model is also suitable for the pure identification of the parameters of links and payload of the manipulator. >

Adaptive sliding mode control based on FLS

Fuzzy logic system (FLS) can be utilized to approximate a nonlinear function. In this paper, an adaptive sliding mode control (SMC) scheme in which FLS is used to approximate the unknown system function f in designing the SMC for nonlinear system is proposed. In order to reduce the approximation errors between the true nonlinear function and fuzzy approximator, a robust adaptive law is also proposed. The stability of the proposed control schemes are proved and the continuous control laws are designed by introducing the boundary layer concepts. These proposed control schemes are applied to an inverted pendulum system and comparisons between the two control schemes are shown in simulations.

Control Algorithm for Stabilization of Tilt Angle of Unmanned Electric Bicycle

Abstract In this papers, we derive a simple kinematic and dynamic formulation of an unmanned electric bicycle. We also check the controllability of the stabilization problem of bicycle. We propose a new control algorithm for the self stabilization of unmanned bicycle with bounded wheel speed and steering angle by using nonlinear control based on the sliding patch and stuck phenomena which was introduced by W. Ham. We also propose a sort of optimal control strategy for steering angle and driving wheel speed that make the length of bicycle’s path be the shortest. From the computer simulation results, we prove the validity of the proposed control algorithm.

Adaptive control based on speed gradient algorithm for robot manipulators

In this short note, we present three types of adaptive parameter update law for the rigid body robot manipulator based on the speed gradient algorithm which is introduced by Fradkov (1979). In the derivation of the new adaptive parameter update laws, we refer the dynamics of rigid body robot manipulators and its error dynamics which were derived by Slotine and Li (1987, 1988). It is shown that the parameter update law which was derived by Slotine belongs to one of three types of adaptive parameter update law proposed in this paper. The three types of adaptive parameter update laws proposed in this paper can ensure the global stability under some conditions such as attainability and convexity in the error dynamics. Computer simulation shows that proposed control algorithm can be used for the tracking problem of rigid body robot manipulators.<<ETX>>

Embedded software and hardware implementation system for a human machine interface based on ISOAgLib

Modern agricultural machinery demands adoption of embedded electronic and remote sensing technology for precision agriculture. One of the electronic devices commonly used is the virtual terminal (VT) for tractors. A VT’s functions and terminology are described in the ISO 11783 standard. This paper presents a control system design and implementation for a VT and some other electronic control units (ECUs) for agricultural vehicles based on that standard. Hardware and software development for the VT is implemented using the ISOAgLib open library, in the advanced embedded system. The main part of the system is an embedded board based on a Samsung S3C6410 ARM11 core microprocessor with a controller area network (CAN) module. Its working environment is Windows Embedded CE 6.0 (WinCE6.0). The ISOAgLib library provides abundant open sources consistent implementation of ISO 11783. It is written in C++ programming language using object-oriented technology. In this paper, we describe an ISO 11783-based tractor control system with a CAN and its implementation in the embedded system. This paper also explains the operation of a CAN-bus device driver in WinCE6.0 and some modifications of ISOAgLib for our target system. The target system consists of the VT, an ECU for the global positioning system (GPS), and an ECU for lighting for an agricultural tractor. The ECU for GPS and the ECU of a light controller are implemented using STM32F107F ARM Cortex M3-based development boards.

3D computer simulation of motion of golf ball in putting green

In this paper we introduce the 3D graphic animation program for simulating the 5 DOF(degree of freedom) motion of golf ball in putting green. We also derive and introduce the dynamics of golf ball and find special physical property which should exist between the friction mechanism of rotational motion and that of translational motion. We choose the Samsung 3D LCD monitor as a graphic monitor and build the simulation program by using OpenGL, MATLAB, 3ds Max, and virtual comport device driver software.

Implementation of a three-dimensional stereo image capture system based on the multi-segment method

Abstract. This paper presents a new model of a complementary metal–oxide–semiconductor (CMOS) camera using combinations of several pin hole camera models, and its validity is verified by using synthesized stereo images based on OpenGL software. Our embedded three-dimensional (3-D) image capturing hardware system consists of five motor controllers and two CMOS camera modules based on an S3C6410 processor. An optimal alignment for capturing nine segment images that have their own convergence planes is implemented using a pi controller based on the measures of alignment and sharpness. A new synthesizing fusion with the optimized nine segmentation images is proposed for the best 3-D depth perception. Based on the experimental results of the disparity values in each of the nine segments, the multi-segment method proposed in this paper is a good method to improve the perception of 3-D depth in stereo images.

Autonomous Tracking Control and Inverse Kinematics of Unmanned Electric Bicycle System

In the former researches for the unmanned bicycle system, we do focus on stabilizing it by using the lateral motion of mass and suggest a control algorithm for steering angle and driving wheel speed for a given desired path. We also suggest a new algorithm for nonlinear inverse kinematic problem which is similar to Piccards iterative method in basic concept. We then propose a tracking control strategy by moving the center of load mass left and right respectively based on the nonlinear compensation-like control studied in the former researches. From the computer simulation results, we can show the effectiveness of the proposed control strategy