Robotics Locomotion and Kinematics
15 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the main focus of the study of motion?

  • Studying environmental impact
  • Understanding robot design (correct)
  • Building structures
  • Analyzing human behavior
  • When considering motion from above, which aspect is being analyzed?

  • Angular acceleration
  • Translational force
  • Linear speed (correct)
  • Rotational movement
  • What term refers to the speed at which an object travels along a curve?

  • Tangent speed (correct)
  • Radial speed
  • Curved velocity
  • Lateral speed
  • Which of the following describes the angle at which an object moves?

    <p>Angular velocity</p> Signup and view all the answers

    In robotic design, what does the term 'linear speed' refer to?

    <p>Speed along a straight path</p> Signup and view all the answers

    What does the term 'angular velocity' refer to in the context provided?

    <p>The rotational speed of an object around a fixed point</p> Signup and view all the answers

    What does the degree of movement depend on?

    <p>The ability to steer</p> Signup and view all the answers

    Which factor can influence the angular velocity according to the provided content?

    <p>The level of tilt applied</p> Signup and view all the answers

    If two wheels are aligned in the same direction, what can be inferred?

    <p>They will turn effectively in the same direction</p> Signup and view all the answers

    What is the implication of a fixed position of rotation in a system?

    <p>It maintains a constant angular velocity</p> Signup and view all the answers

    Which scenario indicates the inability to steer effectively?

    <p>One wheel spinning faster than the other</p> Signup and view all the answers

    What does the ability to tilt slightly around a defined point contribute to?

    <p>Increased capability for change in direction</p> Signup and view all the answers

    What characteristic is not associated with two equal wheels in the context provided?

    <p>They have different gravitational forces</p> Signup and view all the answers

    What is typically true about the center of rotation?

    <p>It is the point that remains stationary while the object rotates around it</p> Signup and view all the answers

    In the context of steering capability, which factor is least likely to influence maneuverability?

    <p>Anchor weight</p> Signup and view all the answers

    Study Notes

    Locomotion

    • Locomotion is the process of causing an autonomous robot to move
    • Forces must be applied to the vehicle to produce motion

    Wheeled Mobile Robots (WMR)

    • WMRs are a combination of various physical (hardware) and computational (software) components
    • Subsystems include:
      • Sensing: measuring robot and environmental properties
      • Locomotion: how the robot moves through its environment
      • Control: generating physical actions for the robot
      • Reasoning: mapping measurements into actions
      • Communication: how robots and external operators communicate

    Kinematics and Dynamics

    • Kinematics: the study of motion without considering forces affecting it. It deals with the relationships between control parameters and the behavior of a system.
    • Dynamics: the study of motion where forces are modeled. It deals with the relationship between force and motion.

    Notation

    • Posture: position (x, y) and orientation (θ)
    • {XmYm}: moving frame
    • {XbYb}: base frame
    • q: robot posture in base frame
    • R(θ): rotation matrix expressing orientation of base frame relative to moving frame

    Wheels

    • Rolling motion occurs along the y-axis
    • Lateral slip occurs along the y-axis
    • z-motion occurs along the z-axis.

    Robot Wheel Parameters

    • For low velocities, rolling is a wheel model
    • Wheel parameters include:
      • r: wheel radius
      • v: wheel linear velocity
      • w: wheel angular velocity
      • t: steering velocity

    Wheel Types

    • Fixed wheel
    • Centered orientable wheel
    • Off-centered orientable wheel (castor wheel)
    • Swedish wheel (omnidirectional property)

    Examples of WMR

    • Bi-wheel type robot: smooth motion, risk of slipping, sometimes uses roller-ball for balance
    • Caterpillar type robot: free motion, complex structure, weakness of the frame
    • Omnidirectional robot: free motion, complex structure

    Mobile Robot Locomotion

    • Instantaneous center of rotation (ICR) or Instantaneous center of curvature (ICC): cross point of all wheel axes

    Degree of Mobility

    • Degree of mobility: the freedom of robot motion
      • 0: cannot move (no ICR)
      • 1: fixed arc motion (only one ICR)
      • 2: variable arc motion (line of ICRs)
      • 3: fully free motion (ICR can be located at any position)

    Degree of Steerability

    • Degree of steerability: the number of centered orientable wheels that can be steered independently
      • 0: no centered orientable wheels
      • 1: one centered orientable wheel
      • 2: two mutually independent centered orientable wheels

    Degree of Maneuverability

    • Degree of maneuverability (δM): δM = δm + δs
      • δm: Degree of mobility
      • δs: Degree of steerability
      • Omnidirectional: δM = 3
      • Differential: δM = 2
      • Omni-Steer : δM = 3
      • Tricycle : δM = 2
      • Two-Steer: δM = 3

    Non-holonomic Constraint

    • Non-holonomic constraint: constraint on feasible velocities of a body
    • Robot can move in some directions (forward, backward), but not others (sideways)

    Types of Driving (Steering)

    • Differential Drive: two driving wheels (plus roller-ball), sensitive to relative velocity
    • Steered wheels: steering wheel + rear wheels, limited turn radius
    • Synchronous Drive
    • Omni-directional
    • Car Drive (Ackerman Steering)

    1-Differential Drive

    • Posture of the robot: P = (x, y, θ)
      • (x, y): position
      • θ: orientation
    • Control input: U = (v, w)
      • v: linear velocity
      • w: angular velocity
    • (Notice: not for each wheel)

    Motion Control

    • Instantaneous center of rotation (ICR): (VR - VL)/L = VR/(R + L/2), R = L(VR + VL)/2(VR - VL). Radius of rotation
      • Straight motion: R = infinity, VR = VL
      • Rotational motion: R = 0, VR = -VL

    2-Tricycle

    • Three wheels, odometers on two rear wheels, steering/power via front wheel
    • Control variables: steering direction (a(t)) and angular velocity (ωs(t)) of steering wheel

    Synchronous Drive

    • Motion of the robot is synchronised around the point of rotation.

    4-Omnidirectional

    • Swedish wheel can move in any direction

    5-Car Drive (Ackerman Steering)

    • Used in motor vehicles
    • Inside front wheel rotates sharper than outside wheel
    • Reduces tire slippage

    Ackerman Steering

    • Lateral wheel separation(d)
    • Longitudinal wheel separation(l)
    • Relative steering angle of inside wheel (θ1)
    • Relative steering angle of outside wheel (θ0)
    • Distance between ICC to center of vehicle(R)
    • Cot(θ1) - Cot(θ0) = d/l.

    Summary (Mobile Robot)

    • Classification of wheels
      • Fixed, centered, off-centered, Swedish
    • Degree of maneuverability= degree of mobility + degree of steerability
    • 5 types of driving methods
      • Differential Drive
      • Steered wheels (tricycle, bicycles, wagon)
      • Synchronous Drive
      • Omni-directional
      • Car Drive (Ackerman Steering)

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Mobile Robot Locomotion PDF

    Description

    This quiz explores the principles of locomotion in robotics, specifically focusing on wheeled mobile robots (WMR). It covers essential subsystems like sensing, control, and dynamics of motion. Dive into kinematics and learn how these concepts enable autonomous movement.

    More Like This

    Robots Móviles Terrestres
    10 questions
    AI Programs vs. Robots Overview
    18 questions

    AI Programs vs. Robots Overview

    AttentiveHeliotrope3672 avatar
    AttentiveHeliotrope3672
    Use Quizgecko on...
    Browser
    Browser