Scheme for Fabricating an Adaptive Controlled Parallel Stewart Type Robot for High Precision Accuracies

The Stewart platform is well known parallel robotic mechanism often used as a flight simulator. Less well known applications Involve robotics and machine tools. In recent years there is a considerable interest in the application of parallel robots because of their greater stiffness and accuracy when compared to the standard serial robots. The most industrial robot manipulators have serial link chains that have characteristics of wide workspace, low stiffness. Error accumulation in end effector’s pose is mainly due to open loop kinematic structures. Therefore the serial link manipulators are not suitable for high speeid and high accurate positioning operations. During the last decade, parallel manipulators have been designed, analyzed and constructed in order to overcome those disadvantages by utilizing high stiffness and low error accumulation characteristics of closed loop kinematic structure. The end effector loads are distributed to simple compression - tension loads among the parallel links so that the bending deformation is not induced. In medical field, parallel robots play a vital role in accurate remote manipulation of a laparoscopic laser dissection tool. Laparoscope’s surgery has gained increasing popularity in recent years and many operative procedures are nowadays performed by this minimaliy invasive approach, requiring fine dexterity and accurate microsurgical technique. However there are some drawbacks in parallel manipulators such as small workspace and very complex dynamics due to dosed chain structure. Therefore it is in general more difficult to control parallel manipulators. Present use of industrial robot is concentrated in rather simple, repetitive tasks, which tend not to require high precision. Manufacturing market analysis predict that in the 2000’s industriaL robots will become increasingly viable in applications which require more precision and sensory sophistication such as machining, medical operations, assembly tasks etc.,. So to have high precision and accuracy parallel robot concept is inevitable.