Robotics Configurations PDF

1/2/23 ROBOTICS CONFIGURATIONS Week 4 IE 454 Industrial Robots Dr. Majed Moosa 1 2 1 1/2/23 Definition of An Industrial Robot A robot is a re-programmable multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the pe...

1/2/23 ROBOTICS CONFIGURATIONS Week 4 IE 454 Industrial Robots Dr. Majed Moosa 1 2 1 1/2/23 Definition of An Industrial Robot A robot is a re-programmable multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks. Robot Institute of America (Group within Society of Manufacturing Engineers) 3 Industrial Robot Examples Vertical articulated type Parallel type Gantry type SCARA type Double arm type 4 2 1/2/23 Typical Applications Ø Material handling Ø Manipulation Ø Measurement 5 Packaging Palletizing Cutting Arc welding Measurement 6 3 1/2/23 Manipulator Structures Ø Mechanical components Ø Mechanical configurations 7 Mechanical Components Ø Robots are serial “chain” mechanisms made up of “links” (generally considered to be rigid), and • “joints” (where relative motion takes place) • Ø Joints connect two links • Link 0 - Joint 1 - Link 1 - Joint 2 - Link 2- 8 4 1/2/23 “Degrees of Freedom” Degrees of freedom (DoF) is the number of independent movements the robot is capable of Ø Ideally, each joint has exactly one degree of freedom Ø • degrees of freedom = number of joints Industrial robots typically have 6 DoF, Ø but 3, 4, 5, and 7 are also common Ø 9 Types of Joints Although there are a few other types, most current industrial robots use one of two types of joints: Ø Prismatic or Translational (also called Linear), and • • Revolute or Rotational Typical robot joints. 10 5 1/2/23 Prismatic Joints Prismatic (Translational, Linear, Rectilinear) joints allow motion along a straight line between two links Ø Link 2 Link 1 11 Revolute Joints Revolute (Rotational) joints allow motion along a circular arc between two links Ø Link 1 Link 2 Relative Motion provided by Revolute Joint 12 6 1/2/23 Mechanical Configurations Industrial robots are categorized by the first three joint types Ø Five different robot configurations: Ø • • • • • Cartesian (or Rectangular), Cylindrical, Spherical (or Polar), Jointed (or Revolute), and SCARA 13 14 7 1/2/23 Cartesian Configuration Ø All three joints are prismatic (PPP) Commonly used for positioning tools, such as dispensers, cutters, drivers, and routers 15 Cartesian Configuration Often highly customizable, with options for X, Y, Z lengths Ø Payloads and speeds vary based on axis length and support structures Ø Simple kinematic equations Ø 16 8 1/2/23 Robot Workspace Workspace is the volume of space reachable by the end-effector mount Ø Everywhere a robot reaches must be within this space Ø Tool orientation and size also important! Ø 17 Cartesian Workspace Ø Ø Easiest workspace to compute and visualize Generally a simple “box” with width (X travel), depth (Y travel), and height (Z travel) 18 9 1/2/23 Gantry Robot Ø A gantry robot is a special type of Cartesian robot Y X Z 19 Gantry Robot Ø Vary widely in size, workspaces from “breadloaf” size to several cubic meters 20 10 1/2/23 Characteristics of Cartesian Robots • Advantages: Ø Ø Ø Ø easy to visualize have better inherent accuracy than most other types easy to program offline highly configurable get the size needed • Disadvantages: Ø Ø Ø Ø Ø not space efficient external frame can be massive Z axis “post” frequently in the way Axes hard to seal Can only reach in front of itself 21 Cylindrical Configuration Ø First joint is revolute (rotation) Next two joints are prismatic (RPP) 22 11 1/2/23 Cylindrical Configuration Vertical Z axis is located inside the base Ø Compact end-of-arm design that allows the robot to "reach" into tight work envelopes without sacrificing speed or repeatability Ø 23 Cylindrical Design Robot 24 12 1/2/23 Cylindrical Workspace Ø Another “easy” workspace to compute and visualize 25 Characteristics of Cylindrical Robots • Advantages: Ø Ø Ø Ø large workspace for size easily computed kinematics can reach all around itself reach and height axes rigid • Disadvantages: Ø Ø Ø cannot reach above itself horizontal axis frequently in the way largely fallen “out of favor” and not common in new designs 26 13 1/2/23 Spherical Configuration Ø First two joints are revolute (rotation) Last joint is prismatic (RRP) 27 Spherical Configuration One of the earliest common robot designs (original UniMate) Ø Used in a variety of industrial tasks such as welding and material handling Ø 28 14 1/2/23 Spherical Design Robots 29 Spherical Workspace Workspace shaped like parts of “orange peel” Ø Harder to compute and visualize Ø 30 15 1/2/23 Spherical Workspace 31 Characteristics of Spherical Robots • Advantages: Ø Ø large workspace for size easily computed kinematics • Disadvantages: Ø Ø Ø has short vertical reach horizontal axis frequently in the way also fallen “out of favor” and not common in new designs 32 16 1/2/23 Anthropomorphic Configuration First three joints are revolute or rotational (RRR) Ø Easily the most common type of modern robot Ø 33 Anthropomorphic Configuration Suitable for a wide variety of industrial tasks, ranging from welding to assembly Ø Often called an anthropomorphic arm because it resembles a human arm Ø 34 17 1/2/23 Anthropomorphic Configuration Ø Anthropomorphic association extends to names of the links & joints Joint 3 - “Elbow” Joint 2 - “Shoulder” Joint 1 - “Waist” 35 Anthropomorphic Configuration Ø Anthropomorphic association extends to names of the links & joints Link 3 - “Forearm” Link 2 - “Upper Arm” Link 1 - “Trunk” 36 18 1/2/23 Anthropomorphic Configuration Ø Very hard to compute and visualize 37 Characteristics of Anthropomorphic Robots • Advantages: Ø Ø Ø excellent reach for size can reach above or below obstacles characteristics similar to human arm large workspace for size • Disadvantages: Ø Ø Ø Ø complicated kinematics difficult to program offline workspace difficult to visualize & compute small errors in first few joints are amplified at end-effector 38 19 1/2/23 KUKA KR 1000 titan Ø The KR 1000 titan is the strongest and biggest 6axis robot available on the market. Ø Loads Payload : 1000 kg Ø Supplementary load: 50 kg Ø Ø Workspace Ø Ø Number of axes: 6 Repeatability: <±0.2 mm Ø Weight: 4950 kg Ø Max. reach: 3202 mm 39 KUKA KR 1000 titan Workspace (mm) 40 20 1/2/23 SCARA Configuration First two links are revolute, last link is prismatic (RRP) Ø SCARA stands for Selective Compliance Assembly Robot Arm Ø 41 SCARA Configuration Rigid in the vertical direction Ø Compliant in the horizontal direction Ø Used for assembly in a vertical direction Ø • circuit board component insertion 42 21 1/2/23 SCARA Workspace Ø Ø Ø Ø Workspace shaped somewhat like a donut maximum outer radius minimum inner radius uniform height 43 Adept Cobra s350 44 22 1/2/23 Characteristics of SCARA Robots • Advantages: Ø Ø Ø Ø fast cycle times excellent repeatability good payload capacity large workspace height axis is rigid • Disadvantages: Ø Ø Ø Ø hard to program off-line often limited to planar surfaces typically small with relatively low load capacity two ways to reach same point 45 Robot Arms & Wrists Ø Most robot arms have 3 “degrees of freedom” • Ø can position the end of the arm at “any” point in 3-D space Robot “wrists” also have 3 “degrees of freedom” • • usually all revolute / rotational joints used to provide the final orientation to the “gripper” or “end-effector” 46 23 1/2/23 Roll - Pitch - Roll Wrist Three main degrees of freedom Can have problems when the first “roll” axis aligns with the last “roll” axis Wrist 47 Yaw - Pitch - Roll Wrist 48 24