Contents 1. INTRODUCTION
Robotics is receiving a great attention in research and industrial communities. However, future robots are required to be more autonomous and intelligent than present robots systems and to be able to execute various types of tasks with minimum or no human intervention. One of the challenges for such an intelligent robot is path planning problem. There are a lot of methods for real time path planning. But Circular arcs and lines[1] have been used to generate trajectories despite the fact that the curvature profile generated is not continuous. SCC-paths (Simple Continuous Curvature paths)[2] for a car-like vehicles can be either a line segment, a circular arc of maximum curvature, or a clothoid arc, but the program is only for going forward, and can not stop at any position by the programmer's mean. Local-planning-method (Quintic polynomial) for AGVs (autonomous guided vehicles)[3] is real time, but it is only for a local path. B-spline Curve for a wheel-type Mobile Robot[4] is continuous curvature and the trajectory passes through specified, but it can not be optimal method, that is because the method makes the curvature of the local path continuous only at a constant velocity, but in [3] and [4] their curvature profile is complex. The method of Clothoid curve[5] derived the robot can start at any condition, and stop at any condition. By linearizing the system's differential equation, we find a condition for critical dumping, which gives appropriate parameters for specilic control rules. So the velocity and acceleration limitations are also needed [7].
