Hyung Gyu Park

Pseudolite Ultrasonic System (PUS) and Gyro integrated system using Kalman filter

The localization of mobile robot is an important part of control problem. Pseudolite Ultrasonic System (PUS) is the method to find an absolute position by using ultrasonic sensor. PUS can be able to estimate the position of mobile robot precisely, in which errors are not accumulated. PUS insure a high accuracy on static state. But mobile robot moves as fast as an estimated position errors are increased. In this paper, we propose a compensation method to increase the accuracy of estimated position on moving robot by using PUS and Gyro. PUS take a 400 milliseconds to estimate mobile robots position one time. This method can calculate a position on increased sampling period, 100 milliseconds at once. Also a Kalman filter is employed for PUS and Gyro integration. This integrated system provides more accuracy of mobile robot position. The performance of PUS and Gyro integrated system showed its effectiveness from the result of the simulation and the experiment.

Lateral control of obstacle avoidance for an autonomous vehicle with laser scanner

This paper describes the development of the obstacle sensing and collision avoidance for Adaptive Cruises Control(ACC) system with an automated vehicle using the laser scanner and RTK - DGPS(Real Time Kinematic - Differential Global Positioning System) system for autonomous navigation. The real scale vehicle for experiment is constructed using RTK-DGPS and laser scanner. Laser scanner is detects the obstacle of the vehicle front. The controller applies to RTK-DGPS and laser scanner based real scale autonomous vehicle, and the performance of the controller and the results of experiments are suggested.

Implementation of Electric Power Assisted Steering System via Hardware-In-Loop-Simulation System

With the development of mechatronics technology in the transporter industry, the electric power assisted steering (EPAS) system has many advantages compared to the hydraulic system. Many manufacturers are developing and applying EPAS systems to improve the performance of the transporter. Using the HILS system developed in the paper, an adaptable EPAS system was developed for real transporter. It was installed in a real, KIA Rio, and tested. Results indicated outstanding performance. Therefore, the developed EPAS can be applied via HILS system.

4WS Unmanned Vehicle Lateral Control Using PUS and Gyro Coupled by Kalman Filtering

The localization of vehicle is an important part of an unmanned vehicle control problem. Pseudolite ultrasonic system(PUS) is the method to find an absolute position with a high accuracy by using ultrasonic sensor. And Gyro is the inertial sensor to measure yaw angle of vehicle. PUS can be able to estimate the position of mobile robot precisely, in which errors are not accumulated. And Gyro is a more faster measure method than PUS. In this paper, we suggest a more accuracy method of calculating PUS which is numerical analysis approach named Newtonian method. And also propose the fusion method to increase the accuracy of estimated angle on moving vehicle by using PUS and Gyro integrated system by Kalman filtering. To control the 4WS unmanned vehicle, the trajectory following algorithm is suggested. And the new concept arbitration of goal controller is suggested. This method considers the desirability function of vehicle state. Finally, the performances of Newtonian method and designed controller were verified from the experimental results with the 4WS vehicle scaled 1/10.

Optimal path planning with holonomic mobile robot using localization vision sensors

Most of the present drive systems of the home service robots and the industrial robots use non-holonomic systems that function only when the robots are moving. For instance, the average vehicle can only be steered when driving so instant movement in all directions is not possible. And that is why the holonomic drive system is attracting attention. In this paper, we propose a holonomic system using three omni-direction wheels to enable instant movement in all directions. Also, IR-projector and vision sensors are proposed for autodrive robots to detect the robots positioning. This system uses an infrared ray projector which processes the image reflected from the infrared reflector installed on the ceiling to detect the absolute position and direction angle of the robot in real time. Robot autodrive using vision sensors is also proposed.

A lateral controller design for an unmanned vehicle

This paper proposes a lateral control system for an unmanned vehicle to improve the responsiveness of the system with a PD control. Heading error can be stabilized and the transient response characteristics can be improved with the controller. In this paper, a mathematical modeling of the vehicle dynamics using two degrees of freedom is used for the controller design. Waypoint tracking method of autonomous navigation was done with the Point to Point algorithm with position and heading measurements from GPS receivers. Performance of the designed controller was verified through experiment with a real vehicle.

Vision-based obstacle avoidance system for autonomous mobile robot in outdoor environment

In this paper, we propose an obstacle avoidance system on based vision sensor for an autonomous mobile robot. For real-time turn angle correction, we obtain the state equation of a mobile robot from input-output continuous data. Each individual image pixel is classified as belonging either to an obstacle or to a non-obstacle based on its color property (HSI color model). The HSI color model is less sensitive to illumination changes than the RGB color model. According to proper conditions and reference zones, we chose a path area, a navigation point, and a turn angle. This method uses a single color camera.

Modeling and robustic control of reduction car using the ultrasonic satellite system

In this paper In this paper, which is one of the part of the development for the automation system in the navigation process, covers the car system. Local detection system based on pseudo-satellite was used to be able to detect the space coordinates and the absolute location with four ultrasonic transmitters and two receivers. Using this system we get the lateral dynamic model of a reduced car by using system identification methods and design a lateral controller. The system input is the steering wheel angle of the vehicle with constant speed and the output is the yaw of the vehicle. With system identification for a basis, to achieve a control objective, we design a controller using the model equation.