Robotics/Machine Vision Robert Love, Venkat Jayaraman July 17, 2008 SSTP Seminar – Lecture 7

Overview Presentation – Parts of a Robot – Robotics Components Joints and Linkages Actuators Sensors Controller – Machine Vision Basic Theory, Application: Harvesters – Image processing Aircraft Control, Bonding Visual Image Correlation, Photogrammetry Discussion Activity 2/2/2016UF Flight Controls Lab2

Parts of a Robot 2/2/2016UF Flight Controls Lab3 Body Effectors Actuators Sensors Controller SensorsControllerActuator End Effector Body

Robot Body is typically defined by links and joints A link is a part, a shape with physical properties. A joint is a constraint on the spatial relations of two or more links. Robot Body

Types of Joints Revolute, Cylindric, Prismatic, Screw, Spherical 2/2/2016UF Flight Controls Lab5 a34a34 a 45, a 56 Mitsubishi PA10-6C

End Effectors – The Component usually attached at the end of the robotic arm to accomplish the desired task Examples : Hand, torch, wheels, weld gun Robot End Effectors End Effector

Actuators: ‘Muscles’ of the robot These can be electric motors, hydraulic systems, pneumatic systems, or any other system that can apply forces to the system. Robot Actuators

Allow for perception. Sensors can be active or passive: Active – derive information from environment’s reaction to robot’s actions, e.g. range sensors. Passive – observers only, e.g. temperature sensors, strain gauge. Robot Sensors Range Sensor Oxygen Sensor

Robot Controller 2/2/2016UF Flight Controls Lab9 Controllers direct a robot how to move. There are two controller paradigms – Open-loop controllers execute robot movement without feedback. – Closed-loop controllers execute robot movement and judge progress with sensors. They can thus compensate for errors.

Kinematics is the study of motion without regard for the forces that cause it. – Refers to all time-based and geometrical properties of motion. – Ignores concepts such as torque, force, mass, energy, and inertia. Forward Kinematics – Determination of the configuration, given the starting configuration of the mechanism and joint angles. Inverse Kinematics - Determination of the joint angles, given the desired position of the end effector. Robot Kinematics

Machine Vision Basic Theory Vision – A powerful sense – Models the human eye Applications – Autonomous vehicles, face recognition, industrial inspection, safety systems, Visual stock control etc No ‘universal’ solution 2/2/2016UF Flight Controls Lab11 A Typical machine vision system

Basic Concepts 2/2/2016UF Flight Controls Lab12 Characteristics of an image – Composed of pixels – Primary colors – red, green and blue Segmentation – Partitioning of the digital image into two or more regions Edge Detection Corner Detection – Corners can be used as Feature points

Robotic Harvesting

2/2/2016UF Flight Controls Lab14 Robot Harvesting Video

Basic Theory Image Processing Basic Image information – focal length, line of sight, field of view, intensity of pixel Projection of point in 3D space onto 2D image plane 2/2/2016UF Flight Controls Lab15

Basic Image Processing Goal: Define Coordinates in 3D Space Methods: – Motion Capture – Photogrammetry: Your digital camera – Stereophotogrammetry/Videogrammetry – Digital Image Correlation – Projector + IR sensor Some analysis tools: – Photoshop (Better, not free), Gimp (open source) Photoshop Gimp – Matlab Image Processing Toolbox (Digitize07-open source) Matlab Image Processing ToolboxDigitize07 – Microsoft Photosynth Live Labs Microsoft Photosynth Live Labs – Johnny Chung’s Wii Remote Project (open source) Johnny Chung’s Wii Remote Project 2/2/2016UF Flight Controls Lab16

Flight Control Basic Process – Extract Feature Points (from intensity spikes in image) – Estimate optic flow vectors – Create estimates of roll, pitch, yaw from average optic flow vectors, use to formulate control model 2/2/2016UF Flight Controls Lab17

Digital Image Correlation 2/2/2016UF Flight Controls Lab18 Power Supply Calibrated Voltage to Flapping Frequency High Speed DIC Cameras Phantom v7 CMOS fps 3 halogen lights VICSNAP, VIC3D Software Electromagnetic Shaker Used for excitation while performing DIC Wings and Mechanism Stinger extends from shaker through load cell to 18 g mechanism Mechanism: 1-20 Hz Spray Paint Speckle Pattern DIC uses temporal tracking of unique regions of speckles Vibration isolation Optical lab table and foam under shaker

Activity Think of an application where a robot could help Make a “design sketch” including: – Task Description (think basic task!) – Basic Actuation Method – Sensors required Share with neighbor and get feedback on how might improve design 2/2/2016UF Flight Controls Lab19