Robot Operation and Control PDF

Robot Operation and Control Lecture 18 IE454 Industrial Robots Dr. Majed Moosa 1 Industrial Robot Defined A general-purpose, programmable machine possessing certain anthropomorphic characteristics § § § § § § § Hazardous work environments Repetitive work cycle Consistency and accuracy Difficult...

Robot Operation and Control Lecture 18 IE454 Industrial Robots Dr. Majed Moosa 1 Industrial Robot Defined A general-purpose, programmable machine possessing certain anthropomorphic characteristics § § § § § § § Hazardous work environments Repetitive work cycle Consistency and accuracy Difficult handling task for humans Multishift operations Reprogrammable, flexible Interfaced to other computer systems 2 1 Robot Anatomy § Manipulator consists of joints and links § Joints provide relative motion Joint3 § Links are rigid members between joints § Various joint types: linear and rotary § Each joint provides a “degree-offreedom” Link1 § Most robots possess five or six degrees-of-freedom § Robot manipulator consists of two sections: Joint1 § Body-and-arm – for positioning of objects in the robot's work volume § Wrist assembly – for orientation of objects Link3 End of Arm Link2 Joint2 Link0 Base 3 Robot Control Systems § Limited sequence control – pick-and-place operations using mechanical stops to set positions § Playback with point-to-point control – records work cycle as a sequence of points, then plays back the sequence during program execution § Playback with continuous path control – greater memory capacity and/or interpolation capability to execute paths (in addition to points) § Intelligent control – exhibits behavior that makes it seem intelligent, e.g., responds to sensor inputs, makes decisions, communicates with humans 14 2 Robot Control System Joint 1 Joint 2 Cell Supervisor Level 2 Controller & Program Level 1 Joint 3 Joint 4 Joint 5 Joint 6 Sensors Level 0 15 End Effectors § The special tooling for a robot that enables it to perform a specific task § Two types: § Grippers – to grasp and manipulate objects (e.g., parts) during work cycle § Tools – to perform a process, e.g., spot welding, spray painting 16 3 Grippers and Tools 17 Working Envelope 18 4 Industrial Robot Applications 1. Material handling applications § Material transfer – pick-and-place, palletizing § Machine loading and/or unloading 2. Processing operations § Welding § Spray coating § Cutting and grinding 3. Assembly and inspection 19 Robotic Arc-Welding Cell § Robot performs flux-cored arc welding (FCAW) operation at one workstation while fitter changes parts at the other workstation 20 5 Robot Programming § Leadthrough programming § Work cycle is taught to robot by moving the manipulator through the required motion cycle and simultaneously entering the program into controller memory for later playback § Teach pendant § Robot programming languages § Textual programming language to enter commands into robot controller § Simulation and off-line programming § Program is prepared at a remote computer terminal and downloaded to robot controller for execution without need for leadthrough methods 21 Leadthrough Programming 1. Powered leadthrough § Common for point-topoint robots § Uses teach pendant 2. Manual leadthrough § Convenient for continuous path control robots § Human programmer physical moves manipulator 22 6 Leadthrough Programming Advantages § § Advantages: § Easily learned by shop personnel § Logical way to teach a robot § No computer programming Disadvantages: § Downtime during programming § Limited programming logic capability § Not compatible with supervisory control 23 Robot Programming § Textural programming languages § Enhanced sensor capabilities § Improved output capabilities to control external equipment § Program logic § Computations and data processing § Communications with supervisory computers 24 7