Industrial and Mobile Robot Collision – Free Motion Planning Using Fuzzy Logic Algorithms

Motion planning is a primary task in robot operation, where the objective is to determine collision-free paths for a robot that works in an environment that contains some moving obstacles (Latombe, 1991; Fugimura, 1991; Tzafestas, 1999). A moving obstacle may be a rigid object, or an object with joints such as an industrial manipulator. In a persistently changing and partially unpredictable environment, robot motion planning must be on line. The planner receives continuous flow of information about occurring events and generates new commands while previous planned motions are being executed. Off – line robot motion planning is a one – shot computation prior to the execution of any motion, and requires all pertinent data to be available in advance. With an automatic motion planner and appropriate sensing devices, robots can adapt quickly to unexpected changes in the environment and be tolerant to modeling errors of the workspace. A basic feature of intelligent robotic systems is the ability to perform autonomously a multitude of tasks without complete a priori information, while adapting to continuous changes in the working environment. Clearly, both robotic manipulators and mobile robots (as well their combination, i.e. mobile manipulators (Seraji, 1998; Tzafestas & Tzafestas, 2001)) need proper motion planning algorithms. For the robotic manipulators, motion planning is a critical aspect due to the fact that the end effector paths have always some form of task constraints. For example, in arc welding the torch may have to follow a complex 3-dimensional path during the welding process. Specifying manually such paths can be tedious and time consuming. For the mobile robots (indoor and outdoor robots) motion planning and autonomous navigation is also a critical issue, as evidenced by applications such as office cleaning, cargo delivery, autonomous wheel chairs for the disabled,etc. Our purpose in this chapter is to present a solution of the motion planner design problem using fuzzy logic and fuzzy reasoning. Firstly, the case of industrial robotic manipulators is considered, and then the class of mobile robots is treated. The methodology adopted is primarily based on some recent results