Baeksuk Chu

Development of Educational Robot Platform Based on Omni-directional Mobile Mechanism

In this paper an omni-directional mobile robot is suggested for educational robot platform. Comparing to other robots, a mobile robot can be easily designed and manufactured due to its simple geometric structure. Moreover, since it is required to have low DOF motion on planar space, fabrication of control system is also simple. In this research, omni-directional wheels were adopted to remove the non-holonomic characteristic of conventional wheels and facilitate control system design. Firstly, geometric structure of a Mecanum wheel which is a most frequently used omni-directional wheel was demonstrated. Then, the organization of the mobile platform was suggested in aspects of mechanism manufacturing and electronic hardware design. Finally, a methodology of control system development was introduced for educational purpose. Due to an intuitive motion generating ability, simple hardware composition, and convenient control algorithm applicability, the omni-directional mobile robot suggested in this research is expected to be a promising educational platform.

Mechanical and electrical design about a mecanum wheeled omni-directional mobile robot

This research deals with design of an omni-directional mobile robot based on Mecanum wheels in mechanical and electrical aspects. To enable immediate motion to any desired directions, so called omni-directionality, a special type of wheel, whose name is Mecanum wheel, is employed. The platform of the suggested mobile robot has conventional squared structure. A stand-alone embedded real-time processor is used for electrical design. In order to make omni-directional motion of the mobile robot, an operator generates a driving signal by adjusting the tilting angle of a joystick. Distance sensors installed around the mobile robot give an ability to recognize environmental situation.

Mobile robot position control algorithm based on multiple ultrasonic distance sensors

This research deals with basic properties of the omni-directional mobile robot based on Mecanum wheels, control system design, and experimental performance evaluation. The suggested mobile robot has a rectangular mobile platform and four Mecanum wheels at each corner. By harmoniously coordinating the four Mecanum wheels, immediate forward/backward, lateral and rotational motion is generated. In electrical design aspect, NI cRIO embedded real-time controller and C Series motion & I/O modules were employed. Ultrasonic sensors installed around the mobile robot can measure environmental situation such as distance between the mobile robot and the side walls. Based on this mechanical and electrical design, a real prototype was manufactured and performance evaluation for position accuracy was conducted. After intensive experiments, it was confirmed that the developed mobile robot guarantees quite decent performances.

Optimal Path Planning in Redundant Sealing Robots

In this paper, we focus on a robotic sealing process in which three robots are used. Each robot can be considered as a 7 axis redundant robot of which the first joint is prismatic and the last 6 joints are revolute. In the factory floor, robot path planning is not a simple problem and is not automated. They need experienced operators who can operate robots by teaching and playing back fashion. However, the robotic sealing process is well organized so the relative positions and orientations of the objects in the floor and robot paths are all pre-determined. Therefore by adopting robotic theory, we can optimally plan robot pathes without using teaching. In this paper, we analyze the sealing robot by using redundant manipulator theory and propose three different methods for path planning. For sealing paths outside of a car body, we propose two methods. The first one is resolving redundancy by using pseudo-inverse of Jacobian and the second one is by using weighted pseudo-inverse of Jacobian. The former is optimal in the sense of energy and the latter is optimal in the sense of manipulability. For sealing paths inside of a car body, we must consider collision avoidance so we propose a performance index for that purpose and a method for optimizing that performance index. We show by simulation that the proposed method can avoid collision with faithfully following the given end effector path.