Kinematic Design and Description of Industrial Robotic Chains

Today, industrial robots can replace humans in carrying out various types of operations. They can as well serve machine tools as to carry out various tasks like welding, handling, painting, assembling, dismantling, foundering, forging, packaging, palletizing ....in different areas of the mechanical, car, aerospace, automotive, electronics ... and other industries. However, the complexity of the industrial process poses difficult problems for insertion and generation of the movements of a robot: the working environment of the robot is often complex and varied (presence of obstacles during the execution of a task for example). One of the objectives concerning the problems of computer-aided design (CAD) of robots is the validation of their topological structures. The robotdesign engineer puts forth assumptions as regards the provision of the links and the joints of the mechanical articulated system. A first validation of this choice is of a geometrical nature (Merlet, 1996). At first sight the design of a mechanical architecture for a robot appears rather simple and yet it presents a very complex basic difficulty, as it must take into account not only the mechanical possibilities of realization but also the possibilities of control’s development, which passes by generating of a mathematical model. The latter strongly affects the mechanical design if good performances are sought. Many methods for mechanism description appeared with the creation of CAD systems (Warnecke, 1977) and (Coiffet, 1992). The existing methods may be separated into two categories: