tailieunhanh - Mechanism Design - Enumeration of Kinematic Structures According to Function P9

Robotic Mechanisms During the last few decades, robot manipulators have been used primarily for repetitive operations and in hazardous environments. Typical applications include parts loading and unloading, radioactive material handling, space and undersea exploration, spot welding, spray painting, sealant application, and some simple component assembly. Recently, there is an increasing interest in making robots more intelligent and more user friendly. Thus, medical-surgery robots, household service robots, microrobots, and others are becoming available. Although much effort has been spent on the development of robot manipulators, the ultimate goal of developing user-friendly, intelligent robots that can emulate human functions is still in its. | Chapter 9 Robotic Mechanisms Introduction During the last few decades robot manipulators have been used primarily for repetitive operations and in hazardous environments. Typical applications include parts loading and unloading radioactive material handling space and undersea exploration spot welding spray painting sealant application and some simple component assembly. Recently there is an increasing interest in making robots more intelligent and more user friendly. Thus medical-surgery robots household service robots microrobots and others are becoming available. Although much effort has been spent on the development of robot manipulators the ultimate goal of developing user-friendly intelligent robots that can emulate human functions is still in its infancy. Major obstacles are some of the key technologies have not been fully developed. In this chapter structural characteristics and structural enumeration of some robotic mechanisms are presented. Parallel Manipulators The development of parallel manipulators can be dated back to the early 1960s when Gough and Whitehall 6 first devised a six-linear jack system for use as a universal tire testing machine. Later Stewart 17 developed a platform manipulator for use as a flight simulator. Since 1980 there has been an increasing interest in the development of parallel manipulators. Potential applications of parallel manipulators include mining machines 3 pointing devices 5 and walking machines 26 . Although parallel manipulators have been studied extensively most of the studies have concentrated on the Stewart-Gough manipulator. The Stewart-Gough manipulator however has a relatively small workspace and its direct kinematics are extremely difficult to solve. Hence it may be advantageous to explore other types of parallel manipulators with the aim of reducing the mechanical complexity and simplifying 2001 by CRC Press LLC the kinematics and dynamics 10 14 16 25 . A structural classification of parallel .