Hak Kyeong Kim

An optimal control method for biped robot with stable walking gait

This paper proposes an optimal control method for a 10 degree of freedom (DOF) biped robot with stable walking gait. The biped robot is modeled as a 3D inverted pendulum. From dynamic model of the 3D inverted pendulum and under the assumption that center of mass (COM) of the biped robot moves on a horizontal constraint plane, zero moment point (ZMP) equations of the biped robot depending on the coordinate of the center of the pelvis link obtained from the dynamic model of the biped robot are given based on the DdasiaAlembertpsilas principle. A walking pattern is generated based on ZMP tracking control systems that are constructed to track the ZMP of the biped robot to zigzag ZMP reference trajectory decided by the footprint of the biped robot. An optimal tracking controller is designed to control the ZMP tracking control system. From the trajectory of the COM of the biped robot and an arc reference input of the swinging leg, the inverse kinematics solved by the solid geometry method is used to compute the angles of each joint of the biped robot. The simulation and experimental results show the effectiveness of this proposed control method.

Decentralized Control Design for Welding Mobile Manipulator

This paper presents a decentralized motion control method of welding mobile manipulators which use for welding in many industrial fields Major requirements of welding robots are accuracy, robust, and reliability so that they can substitute for the welders in hazardous and worse environment To do this, the manipulator has to take the torch tracking along a welding trajectory with a constant velocity and a constant heading angle, and the mobile-platform has to move to avoid the singularities of the manipulator In this paper, we develop a kinematic model of the mobile-platform and the manipulator as two separate subsystems With the idea that the manipulator can avoid the singularities by keeping its initial configuration in the welding process, the redundancy problem of system is solved by introducing the platform mobility to realize this idea Two controllers for the mobile-platform and the manipulator were designed, respectively, and the relationships between two controllers are the velocities of two subsystems Control laws are obtained based on the Lyapunov function to ensure the asymptotical stability of the system The simulation and experimental results show the effectiveness of the proposed controllers

Development and controller design of wheeled-type pipe inspection robot

A wheeled-type pipe inspection robot designed to work in 300 to 500 mm diameter pipe with multiple elbows is introduced in this paper. The robot consists of two modules-active module and passive module. Each module has three wheel configurations with different mechanism to expand the wheels. A proportional integral derivative controller is designed for the robot to follow reference linear velocity and reference angular velocity. Simulations and experiments are conducted to verify performances of the proposed controlled robot. The results demonstrate that the robot with the designed controller can work well by following the reference velocity.

A Vision System for Identifying Structural Vibration in Civil Engineering Constructions

Civil engineering constructions need to measure their conditions and states using many kinds of contact sensors because they are so huge and change very slowly. The constructions are built for all the citizens, so they must be measured carefully. In this paper, the development results of vision system for the vibration measurement in the civil engineering constructions using camera system are proposed. The system consists of a CCD digital camera, a telephoto lens, Pan & Tilt equipments and a dynamic measurement program. The camera calibrations are carried out for an experiment of the dynamic measurement system on a bridge. The experimental results are achieved on the bridges to verify the effectiveness of and its applicability of the proposed vision system in the practical fields

Trajectory Tracking Algorithm for Automatic Guided Vehicle Based on Adaptive Backstepping Control Method

This paper proposes trajectory tracking algorithm for differential drive type of Automatic Guided Vehicle (AGV) system with the unknown wheel radii using adaptive backstepping control method. To guarantee the tracking errors go to zero, backstepping control method is proposed. By choosing appropriate Lyapunov function based on its kinematic modeling, system stability is guaranteed and a control law can be obtained. In this paper, the unknown radii of left and right wheels caused by uneven load distribution or manufacturing imperfection are considered. To solve this problem, an adaptive law is proposed to estimate the changing of wheels radii. The simulation and experimental results show that the proposed controller successfully estimates the unknown parameters and tracks the reference trajectories.

Adaptive Motion Controller Design for an Omnidirectional AGV Based on Laser Sensor

Automatic Guided Vehicles (AGVs) are used in many factories. This paper proposes an adaptive tracking controller of omnidirectional AGV (OAGV) with the constant unknown mass and the uncertain bounded friction and slip force vector exerted on the driving wheels. The OAGV consists of 3 wheels with three omnidirectional wheels are equally spaced 1200 from one another. The controller based on the dynamic modeling is designed based on Lyapunov stability theory to stabilize the OAGV to follow a sharp edge trajectory and OAGV doesn’t change heading direction during movement. A laser sensor device NAV200 is used to detect the OAGV position in door environment in real-time. The simulation and experiment results are presented to demonstrate the effectiveness of the proposed controller.

Adaptive Backstepping Control Design for Trajectory Tracking of Automatic Guided Vehicles

This paper is to design an adaptive trajectory tracking controller for an Automatic Guided Vehicle (AGV) to track the desired reference trajectory with unknown slip. To do this task, the followings are done. Firstly, system description and mathematical modelings of a differential drive AGV system are presented. Kinematic model of AGV is derived based on the wheel configuration and the nonholonomic constraint. Dynamic model of AGV is obtained from the Lagrangian formula. Secondly, an adaptive backstepping trajectory tracking controller is designed. By choosing appropriate Lyapunov function based on its kinematic modeling of AGV system with unknown slip parameter stability is guaranteed, a control law and an update law to estimate the unknown slip parameter can be obtained. The simulation and experimental results show that the proposed controller successfully estimates the unknown parameters and tracks a reference trajectory.

Object following control of six-legged robot using Kinect camera.

This paper proposes a vision-based object following system for the six-legged robot using Kinect camera. To do this task, the followings are done. First, for image processing, a Kinect camera is installed on the six-legged robot. The interesting moving object is detected by a color-based object detection method. The local coordinates of the detected object are obtained to provide the position of the object. Second, the backstepping method using Lyapunov function is adopted to design a controller for the six-legged robot to achieve object following. Finally, the simulation and experimental results are presented to show the effectiveness of the proposed control method.

Trajectory tracking controller design for AGV using laser sensor based positioning system

This paper introduces a tracking controller for Automatic Guided Vehicles (AGV) to track a desired trajectory. The use of the nonlinear Lyapunov technique provides robustness for load disturbance and sensor noise. Based on kinematic model, a trajectory tracking controller of AGV is proposed. System stability is verified by Lyapunov stability. A laser sensor device NAV200 is used to detect the AGV position in door environment in real-time. For simulation and experiment, software and hardware are described. The AGV consists of 4 wheels with two passive wheels and two driving wheels. A controller is developed based on industrial computer. The effectiveness of the proposed controller is proved by simulation and experimental results.

A Model Reference Adaptive Controller for Belt Conveyors of Induction Conveyor Line in Cross-Belt Sorting System with Input Saturation

Model reference adaptive controller for belt conveyors of induction conveyor line in cross-belt sorting system with input saturation subjected to parametric uncertainties and input saturation is proposed in this paper. There exist 3 inputs and 3 outputs in the proposed controller for belt conveyors of induction conveyor line in cross-belt sorting system named the MIMO linear system. In this controller, an auxiliary system is introduced for compensating the error dynamics of the MIMO linear system when the saturation input occurs. Therefore, the steady state error is guaranteed to be bounded when a saturated input error does not equal to zero. Finally, the experimental results are shown to verify the effectiveness and the performance of the proposed controller for the MIMO linear system with input saturation and a MRAC controller for that without input saturation.