tailieunhanh - Mechanisms and Mechanical Devices Sourcebook Episode 1 Part 2

Tham khảo tài liệu 'mechanisms and mechanical devices sourcebook episode 1 part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CHAPTER 2 ROBOT MECHANISMS INDUSTRIAL ROBOTS The programmability of the industrial robot using computer software makes it both flexible in the way it works and versatile in the range of tasks it can accomplish. The most generally accepted definition of a robot is a reprogrammable multifunction manipulator designed to move material parts tools or specialized devices through variable programmed motions to perform a variety of tasks. Robots can be floor-standing bench-top or mobile. Robots are classified in ways that relate to the characteristics of their control systems manipulator or arm geometry and modes of operation. There is no common agreement on or standardizations of these designations in the literature or among robot specialists around the world. A basic robot classification relates to overall performance and distinguishes between limited and unlimited sequence control. Four classes are generally recognized limited sequence and three forms of unlimited sequence point-to-point continuous path and controlled path. These designations refer to the path taken by the end effector or tool at the end of the robot arm as it moves between operations. Another classification related to control is nonservoed versus servoed. Nonservoed implies open-loop control or no closed-loop feedback in the system. By contrast servoed means that some form of closed-loop feedback is used in the system typically based on sensing velocity position or both. Limited sequence also implies nonservoed control while unlimited sequence can be achieved with point-to-point continuous-path or controlled-path modes of operation. Robots are powered by electric hydraulic or pneumatic motors or actuators. Electric motor power is most popular for the major axes of floor-standing industrial robots today. Hydraulic-drive robots are generally assigned to heavy-duty lifting applications. Some electric and hydraulic robots are equipped with pneumatic-controlled tools or end effectors. The .