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Construction and Motion control of a mobile robot using Visual Roadmap. By: Harshad Sawhney Guide: Dr. Amitabha Mukerjee. Objective. Source. Destination. Introduction. Inspiration From Human Brain. The roadmap approach, captures connectivity of robot’s free space.
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Construction and Motion control of a mobilerobot using Visual Roadmap By: HarshadSawhney Guide: Dr. AmitabhaMukerjee
Objective Source Destination
Introduction • Inspiration From Human Brain. • The roadmap approach, captures connectivity of robot’s free space. • 3-DOF mobile robot constructed.
Construction Of Robot Receives Data UART communication Lithium-Ion battery Wireless module Xbee • Microcontroller Arduino 2 DC motors Motor driver Image Source: robokits.co.in Major Components:
Flow Chart of Robot Navigation NO YES Stop
Image Pre-processing • 10k images taken. • Background subtraction performed. • Parameters extracted - robot navigation. Few images from dataset
Initial Image Background subtraction
Distance Metric Computation • L2-norm expansion method. • Dist(X, Y) = sqrt(||X||2 + ||Y||2 - 2*||Y’X||)
Graph generation • k-nearest neighbours calculated. • Robot location as nodes. • k=6 taken. • k=10 ; robot jumps larger distance.
Shortest path calculation • Without Obstacles: • Dijkstra’s algorithm used. Shortest Path Graph
Shortest path calculation • With obstacles: • Obstacles image extracted. • Compared the image with the dataset. • Nodes and edges removed. • Reduced to no obstacles case.
Obstacle Image Image of environment with obstacles Obstacle image extraction
Shortest path calculation Shortest Path Graph with obstacles in the environment
Robot Motion Control • Feed the nodes. • Camera: Negative closed loop feedback mechanism. • Reach till destination. • Real Time.
Algorithm for controlling robot • (x, y, Ɵ): Robot current parameters • (x’, y’, Ɵ’): Node parameters • Ɵ : Robot vector angle. • Ɵ1 : Position of robot and node vector angle. • Step1: Ƒ = | Ɵ - Ɵ1 | • Rotate till | Ƒ | < ɛ • Step 2: Move till | (x-x’)2+ (y-y’)2|< ɛ1
Algorithm for controlling robot • Step 3: Align till | Ɵ - Ɵ’| < ɛ2 • Steps executed in increasing order of priority. • Thus, the camera provides negative feedback closed loop system.
Results • Robot accurately navigates. • Videos demonstrating robot navigation.
Challenges • Distance metric computation: limits sampling density. • Real time motion: possibly leading to collisions.
Future Work • Dynamic obstacle avoidance • Update graph first time; use relative changes in image for future considerations.
References [1] AmitabhaMukerjee, M SeethaRamaiah, Sadbodh Sharma, ArindamChakraborty, “The Baby at One Month: Visuo-motor discovery in the infant robot". [2] Joshua B. Tenenbaum, Vin de Silva, John C. Langford, “A Global Geometric Framework for Nonlinear Dimensionality Reduction", 2000. [3] Jean-Claude Latombe, "Robot Motion Planning”, Edition en anglais. Springer, 1990. [4] Choset, Howie,Principles of robot motion: theory, algorithms, and implementations. MIT press, 2005. [5] Seth Hutchinson, Gregory D Hager, and Peter I Corke. A tutorial on visual servo control. Robotics and Automation, IEEE Transactions on, 12(5):651{670, 1996.