Robotics 1.01 Lecture 1 01. Introduction about Robotics HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.02 Lecture 1 CONTENTS 1. What is a Robot? 2. Historical Development 3. Robot Components 4. Robot Classifications 5. Robot Applications 6. Robot’s Kinematics, Dynamics, and Control HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.03 Lecture 1 1. WHAT IS A ROBOT ? • Webster’s Dictionary: An automatic device that performs functions ordinarily ascribed to human beings โน washing machine ≡ robot ? • Robotics Institute of America (RIA) definition: A robot (industrial robot) is a reprogrammable multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks • From the engineering point of view: Robots are complex, versatile devices that contain a mechanical structure, a sensory system, and an automatic control system. Theoretical fundamentals of robotics rely on the results of research in mechanics, electric, electronics, automatic control, mathematics, and computer sciences ๏ There is no precise definition yet for the word of robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.04 Lecture 1 1. WHAT IS A ROBOT ? • By general agreement, a robot is: A programmable machine that imitates the actions or appearance of an intelligent creature – usually a human • To qualify as a robot, a machine must be able to: - Sensing and perception: get information from its surroundings - Carry out different tasks: Locomotion or manipulation, do something physical – such as move or manipulate objects - Re-programmable: can do different things - Function autonomously - Interact with human beings HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.05 Lecture 1 2. HISTORICAL DEVELOPMENT • • • • The first position controlling apparatus, spray painting, 1938 The first automata were probably Grey Walter’s machina, 1940s The first industrial modern robots Unimates, J. Engelberger, 1960s The first autonomous robots John’s Hopkins beast, Johns Hopkins University Applied Physics Lab, early 1960s Grey Walter’s Machina Unimates HCM City Univ. of Technology, Faculty of Mechanical Engineering John’s Hopkins beast Phung Tri Cong Robotics 1.06 Lecture 1 2. HISTORICAL DEVELOPMENT • The first programmable robot was designed by George Devol, 1954 • The first commercially available robot appeared on the market, 1959 • Robotic manipulators were used in industries after 1960, and saw sky rocketing growth in the 80s • Today, a robot is a multi-disciplinary engineering device - Mechanical engineering: design of mechanical components, arms, end-effectors, and also is responsible for kinematics, dynamics and control analyses of robots - Electrical engineering: actuators, sensors, power, and control systems - System design engineering: perception, sensing, and control methods of robots - Programming or software engineering: logic, intelligence, communication, and networking HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.07 Lecture 1 2. HISTORICAL DEVELOPMENT • Robot Evolution (100 BC – 2020) HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.08 Lecture 1 3. ROBOT COMPONENTS 3.1. Link • Link: rigid bodies having nodes (points for attachment to other links), e.g. binary (2 nodes), ternary (3 nodes) and quaternary (4 nodes) links • A robot arm or a robot link is a rigid member that may have relative motion with respect to all other links • In the shown mechanism - Number of bars: 13 - Binary links: 05 - Ternary links: 02 ([3, 10, 11], [6, 12,13]) - Number of links: 07 HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.09 Lecture 1 3. ROBOT COMPONENTS 3.2. Joint • Joint: connections between 2 links at their nodes where their relative motion can be expressed by a single coordinate • Joints are typically - Revolute (rotary): a revolute joint (๐ ), is like a hinge and allows relative rotation between two links - Prismatic (translation): a prismatic joint (๐), allows a translation of relative motion between two links Revolute joint HCM City Univ. of Technology, Faculty of Mechanical Engineering Prismatic joint Phung Tri Cong Robotics 1.10 Lecture 1 3. ROBOT COMPONENTS • Axis of joint: relative rotation of connected links by a revolute joint occurs about a line, translation of two connected links by a prismatic joint occurs along a line • Joint coordinate (joint variable): the value of the single coordinate describing the relative position of two connected links at a joint. It is an angle for a revolute joint, and a distance for a prismatic joint • A symbolic illustration of revolute and prismatic joints in robotics Symbolic illustration of revolute joints HCM City Univ. of Technology, Faculty of Mechanical Engineering Symbolic illustration of prismatic joints Phung Tri Cong Robotics 1.11 Lecture 1 3. ROBOT COMPONENTS • There are six different lower pair joints: revolute, prismatic, cylindrical, screw, spherical, and planar Revolute Prismatic Cylindrical Screw Spherical Planar HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.12 Lecture 1 3. ROBOT COMPONENTS • Active joint: the coordinate of an joint is controlled by an actuator. Active joints are usually prismatic joints or revolute joints • Passive joint (inactive or free joints): have no actuator. Passive joint is a function of the coordinates of active joints and the geometry of the robot arms. Passive joints may be any of the lower pair joints that provide surface contact • Revolute and prismatic joints are the most common joints that are utilized in serial robotic manipulators, provide one degree of freedom (DOF) • The other joint types are merely implementations to achieve the same function or provide additional DOF • Typically the manipulator should possess at least six DOF: three for positioning and three for orientation • A manipulator having more than six DOF is referred to as a kinematically redundant manipulator HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.13 Lecture 1 3. ROBOT COMPONENTS 3.3. Manipulator • The main body of a robot consisting of the links, joints, and other structural elements, is called the manipulator • A manipulator becomes a robot when the wrist and gripper are attached, and the control system is implemented • In literature robots and manipulators are utilized equivalently and both refer to robots. Figure schematically illustrates a 3๐ manipulator HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.14 Lecture 1 3. ROBOT COMPONENTS 3.4. Wrist • The joints in the kinematic chain of a robot between the forearm and end-effector are referred to as the wrist • It is common to design manipulators with spherical wrists, by which it means three revolute joint axes intersect at a common point called the wrist point • The spherical wrist greatly simplifies the kinematic analysis effectively, allowing us to decouple the positioning and orienting of the end effector • The manipulator will possess three DOF for position (by three joints in the arm). The number of DOF for orientation depend on the wrist • The number of DOF of a wrist (one, two, or three) depends on the desired application HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.15 Lecture 1 3. ROBOT COMPONENTS 3.5. End-Effectors • The end-effector is the part mounted on the last link to do the required job of the robot • The simplest end-effector is a gripper, which is usually capable of only two actions: opening and closing 2-Finger 3-Finger Concentric 2-Finger Angular Multi-Finger Parallel Grippers Grippers Grippers Concentric Grippers • The wrist and end-effector assembly is also called a hand HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.16 Lecture 1 3. ROBOT COMPONENTS 3.6. Actuators • Actuators are drivers acting as the muscles of robots to change their configuration • The actuators provide power to act on the mechanical structure against gravity, inertia, and other external forces to modify the geometric location of the robot’s hand • The actuators can be of electric, hydraulic, or pneumatic type and have to be controllable HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.17 Lecture 1 3. ROBOT COMPONENTS 3.7. Sensors • Sensors: the elements used for detecting and collecting information about internal and environmental states • The most important information need to be sensed: joint position, velocity, acceleration, and force • Sensors send information about each link and joint to the control unit, and the control unit determines the configuration of the robot 3.8. Controllers The controller or control unit has three roles • Information role: collecting and processing the information from sensors • Decision role: planning the geometric motion of the robot structure • Communication role: organizing the information between the robot and its environment The control unit includes the processor and software HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.18 Lecture 1 4. ROBOT CLASSIFICATIONS โ According to Japanese Industrial Robot Association Class 1 Manual handling devices A device with multi DOF that is actuated by an operator Class 2 Fixed sequence robot A device that performs the successive stages of a task according to a predetermined and fixed program Class 3 Variable sequence robot A device that performs the successive stages of a task according to a predetermined but programmable method Class 4 Playback robot A human operator performs the task manually by leading the robot, which records the motions for later playback. The robot repeats the same motions according to the recorded information HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.19 Lecture 1 4. ROBOT CLASSIFICATIONS Class 5 Numerical control robot The operator supplies the robot with a motion program rather than teaching it the task manually Class 6 Intelligent robot A robot with the ability to understand its environment and the ability to successfully complete a task despite changes in the surrounding conditions under which it is to be performed HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.20 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Research Field There are many types of robot • Serial robot (Industrial manipulator) • Parallel robot • Mobile robot • Humanoid robot • Walking robot • In-pipe robot • Fish robot •… HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.21 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Research Field Serial Robot KUKA Robot ABB Robot PUMA Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.22 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Research Field Parallel Robot ABB HCM City Univ. of Technology, Faculty of Mechanical Engineering Deltapod Phung Tri Cong Robotics 1.23 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Research Field Parallel Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.24 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Research Field Mobile Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.25 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Research Field Humanoid Robot ASIMO HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.26 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Research Field Humanoid Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.27 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Research Field Walking Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.28 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Research Field In-pipe Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.29 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Research Field Fish Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.30 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Mechanical Structure Cartesian/Gantry Robots Robot whose arm has 3 prismatic joints, whose axes are coincident with a Cartesian coordinate Used for pick and place, assembly operations, application of sealant, and arc welding HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.31 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Mechanical Structure Spherical/Polar Robots Are stationary robot arms with spherical or near-spherical work envelopes that can be positioned in a polar coordinate system 2 revolute joints + 1 prismatic joint HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.32 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Mechanical Structure Cylindrical Robots This type of robot has a motion that resembles a tank turret. Rotates around vertical axis, pivot point provides vertical motion. Telescoping boom can extend or retract 1 revolute joints + 2 prismatic joints HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.33 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Mechanical Structure SCARA Robots (Selective Compliance Assembly Robot Arm) Ideal for use in applications that require limited vertical motion but a large degree of horizontal travel Uses pick & place, sealant application, and assembly HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.34 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Mechanical Structure Articulated Robots A robot whose arm has at least 3 rotary joints Uses for assembly, welding, painting HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.35 Lecture 1 4. ROBOT CLASSIFICATIONS โ Classification by Mechanical Structure Parallel Robots A robot whose arms have concurrent prismatic or rotary joints Mobile platform for flight simulators HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.36 Lecture 1 5. ROBOT APPLICATIONS • According to the category of application - Machine loading - Sampling - Pick and place - Manufacturing - Welding - Biomedical - Painting - Assisting - Assembling - Remote controlled mobile - Inspecting - Tele-robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.37 Lecture 1 5. ROBOT APPLICATIONS Painting Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.38 Lecture 1 5. ROBOT APPLICATIONS Welding Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.39 Lecture 1 5. ROBOT APPLICATIONS Welding Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.40 Lecture 1 5. ROBOT APPLICATIONS Assembly Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.41 Lecture 1 5. ROBOT APPLICATIONS Assembly Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.42 Lecture 1 5. ROBOT APPLICATIONS Loading Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.43 Lecture 1 5. ROBOT APPLICATIONS Loading Robot HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.44 Lecture 1 6. ROBOT’S KINEMATICS, DYNAMICS, AND CONTROL 6.1. Kinematics • Kinematics is a branch of science that analyzes motion with no attention to what causes the motion • Forward kinematics Give the kinematical data of the joint coordinates Find the end-effector’s data in the base coordinate frame • Inverse kinematics Give the kinematics data of the end-effector in the base coordinate frame Find the kinematic data of the joint coordinates • Inverse kinematics is highly nonlinear and usually a much more difficult problem than the forward kinematics problem HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.45 Lecture 1 6. ROBOT’S KINEMATICS, DYNAMICS, AND CONTROL 6.2. Dynamics • Dynamics is the study of systems that undergo changes of state as time evolves • Direct dynamics Give set of initial conditions and torques at active joints Find predict the motion of the robot • Inverse dynamics Give set of positions, velocities, and accelerations Find the forces and torques necessary to generate the prescribed trajectory HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.46 Lecture 1 6. ROBOT’S KINEMATICS, DYNAMICS, AND CONTROL 6.3. Control • The robot control problem Give the desired motion of the end-effector Find the control inputs in robot joint coordinates • Sensors generate data to find the actual state of the robot at joint space. This implies a requirement for expressing the kinematic variables in Cartesian space to be transformed into their equivalent joint coordinate space • The robot control comprises three computational problems 1. Determination of the trajectory in Cartesian coordinate space 2. Transformation of the Cartesian trajectory into equivalent joint coordinate space 3. Generation of the motor torque commands to realize the trajectory HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.47 Lecture 1 6. ROBOT’S KINEMATICS, DYNAMICS, AND CONTROL 6.4. Review • Unit Vectors Unit vectors ๐เท , ๐,ฦธ ๐เท is a set of three unit vectors whose directions form a positive orthogonal triad, we have ๐ฦธ2 = ๐2ฦธ = ๐เท 2 = 1 ๐ฦธ × ๐เท = ๐,ฦธ ๐เท × ๐ฦธ = ๐,ฦธ ๐ฦธ × ๐ฦธ = ๐เท ๐ฦธ โ ๐ฦธ = ๐ฦธ โ ๐เท = ๐เท โ ๐ฦธ = 0 Vector equation ๐ต ๐ = ๐ต๐ + ๐ต๐ ๐ต: indicating the frame the vectors are expressed in HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.48 Lecture 1 6. ROBOT’S KINEMATICS, DYNAMICS, AND CONTROL Reference Frame and Coordinate System - Reference frames: particular perspective employed by the analyst to describe the motion of links - Fixed frame: reference frame (motionless) attached to the ground - Moving frame: reference frame that moves with a link - Global reference frame: fixed frame in which a robot moves - Moving reference frame: the local reference frame HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong Robotics 1.49 Lecture 1 6. ROBOT’S KINEMATICS, DYNAMICS, AND CONTROL - Coordinate system determines the way to describe the motion in each reference frame โน Coordinate system ≠ reference frames - In this course, Cartesian system is the only system to be used โน reference frame โบ coordinate frame โบ coordinate system - The position of point ๐ in + Global coordinate frame ๐ ๐บ เทก= ๐ ๐ = ๐๐ผแ + ๐๐ฝแ + ๐๐พ ๐ + Body coordinate frame ๐ฅ ๐ต ๐ = ๐ฅ๐ฦธ + ๐ฆ๐ฦธ + ๐ง๐เท = ๐ฆ ๐ง (๐ฅ, ๐ฆ, ๐ง), (๐, ๐, ๐): coordinates or components HCM City Univ. of Technology, Faculty of Mechanical Engineering Phung Tri Cong
