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| == Information ==
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| Purpose: Learning basic knowledge of robotics
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| Lecture: CS223A, Stanford University
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| Date: Jan 21, 2019 ~
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| * Prerequite
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| * Linear Algebra
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| * Numerical Analysis
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| == Reference ==
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| Material: Copy from Stanford
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| Video clips: https://www.youtube.com/watch?v=0yD3uBshJB0&list=PL65CC0384A1798ADF
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| == Study List ==
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| === Lecture 1: Spatial Description ===
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| General Manipulator: Robot Arm, using Revolute joint, Prismatic joint
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| * Robot Arm: base, link, joint, end-effector
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| * Revolute joint: Rotation movement, 1 Degree of Fredom(DoF)
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| * Prismatic joint: Linear movement, 1 DoF
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| * Denote joint type using ε(0 for revolute, 1for prismatic)
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| Discription of body1 (9 parameters)
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| * Link location: 3 points (Each point has 3 parameters)
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| Discription of body2 (6 parameters)
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| * Body orientation: 3 parameter
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| * Point on the body: 3 parameter
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| => Robot arm(n:links, 1: base) has n DoF
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| Transformation
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| * Pure Rotation
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| * Pure Translation
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| * General Tasformation
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| * Inverse Transformation
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| Configuration Representation
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| There is no universial agreement in the field of robotics as to what is the best orientation representation.
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| Because each representation hase advantages and shortcomings
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| * Direction Cosines:
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| * Euler angle representation: ZYX, angle(α, β, γ)
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| * Fixed angle representation: XYZ, angle(γ, β, α)
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| * Inverse of an orientation representation
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| === Lecture 2: Direct Kinematics ===
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| Previous
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| * Independent of the structure of the manipulator
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| Introduction
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| * A set of parameters specific to each manipulator
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| * ex) rotation, translation, link of manipulator
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| * Forware Kinematics
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| * Inverse Kinematics
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| Link Description
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| * Manipulator: Consist of a chain of links from base
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| * Consecutive links are connected by joints which exert the degree of freedom.
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| D-H Parameter
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| * link length(a): length along the common normal from axis (i-1) to axis i
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| * link twist(α): angle between this parallel line and axis (i-1)
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| * link offset(θ): distance alont the line on axis i between the common normal for link (i-1) and common normal for link i
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| * joint angle(d): angle between the two common normal for link (i-1) and common normal for link i
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| * Revolute joint: joint angle(variable), link offset(constant)
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| * Prismatic joint: joint angle(constant), link offset(variable)
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| * a, α: describe link
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| * d, θ: describe the link's connection
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| Conventions for First and Last Link
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| * Once robot structure is set link length & link twist is determined.
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| * a(i) and α(i) depend on joint axes i and i+1
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| Axes 1 to n: determined => a(1), a(2), ,,,, a(n-1) and α(1), α(2), ,,,,a(n-1)
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| * d(i) and θ(i) depend on
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| Attaching Frames to links
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| * ex1) RRR (Revolute-Revolute-Revolute) Manipulator
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| * ex2) RPRR (Revolute-Prismatic-Revolute-Revolute) Manipulator
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| Propagation of Frames
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| * Show how to calculate matrix about D-H parameter
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| * Reference
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| http://www.adrian.zentner.name/content/projects/xml/x3d/robot/res/Denavit-Hartenberg.gif
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| Kinematics of Manipulators
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| * Example of robot arm (Stanford Scheinman Arm)
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| * Reference
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| http://infolab.stanford.edu/pub/voy/museum/pictures/display/robots/StanfordArm.jpg
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| Direct(forward) Kinematics
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| * Mapping between the joint space of dimension n and the task space of manipulator of dimension m
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| * Called the "Geometric Model of the manipulator"
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| (It is determinded solely by knowing the geometry of manipulator)
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| * q(i) = ε'(i)θ(i) + ε(i)d(i)
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| * X = f(q)
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| === Lecture 3: Inverse Kinematics ===
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| Introduction
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| * Difficult task: Multiplicity or non-existence of potential soultions
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| * Problem: find q given T(B,W) or x / find q = f^(-1)(x)
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| Closed Form Solutions
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| Algebraic: solution is found using the fact that θ1+θ2+θ3 = a0
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| Geometric: there are two possible solutions
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| Piper's Solution
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| ???
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| Existence of Solution
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| * If these two equations are correct, solution of the inverse kinematics exists
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| * However, sometimes there is no solution because of limitation of robot model
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| Workplace of the Manipulator
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| * Workspace: the set of points that can be reached with the mainpulator
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| * Joint limitation is always defined by the mechanical design of the manipulator
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| * Related question: # of possible solutions
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| * Reachable Workspace: the set of points that can be reached in at least one conficuration of the manipulator
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| * Dextrous workspace: the set of points that can be reached by any possible orientation of the end-effector, important in the motion planning with obstacles (Reachable Workspace > Dextrous workspace)
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| # of Solutions
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| 6R manipulator: 16 solutions
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| 5RP manipulator: 16 solutions
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| 4R2P manipulator: 8 solutions
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| 3R3P manipulator: 2 solutions
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| in-parallel structures: 40 solutions
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| * Puma Robot
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| Reference
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| https://d2t1xqejof9utc.cloudfront.net/screenshots/pics/45f6b6d1d881d687d15e29d47f181a6f/large.PNG
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| * Stanford Scheinman Arm
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| Reference
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| http://infolab.stanford.edu/pub/voy/museum/pictures/display/robots/IMG_2404ArmFrontPeekingOut.JPG
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| == Comments ==
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| 선배님 너무 멋있어여 - [[조예진]]
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| * 새싹 준비입니다 - [[우준혁]]
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| == Closed ==
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| == Back page ==
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| * [[우준혁]]
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