Just Add Wheels: Just Add Wheels: Leveraging Commodity Leveraging Commodity

Laptop Hardware for Laptop Hardware for Robotics EducationRobotics Education

Jonathan Kelly, Jonathan Binney, Arvind Pereira, Omair Khan and Gaurav S. Sukhatme

Robotic Embedded Systems LaboratoryDepartment of Computer ScienceUniversity of Southern California

Sunday, July 13, 2008

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IntroductionIntroduction

• We propose using commodity laptop hardware for robotics education.

• We motivate the approach by discussing relevant studies and statistics.

• We then describe our prototype laptop robot, including software based on the open source Player-Stage package.

• We present results from monocular SLAM and bump detection experiments, using laptop sensors.

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Talk OutlineTalk Outline

• Introduction

• Motivation

• Leveraging Laptop Hardware for Education

• The “LapBot”, a Prototype Laptop Robot

• Monocular SLAM

• Bump Sensing

• Conclusions and Future Work

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MotivationMotivation• Robotics projects are fun and exciting –

excellent for learning about physics, math, computer science etc.

• Can be used to motivate students who may not otherwise choose to pursue Science or Engineering (Blank 2006).

• Numerous barriers to widespread adoption of robotics curriculum, however, at both college and K-12 levels.

• Include lack of teacher training, suitable educational resources, and affordable robot platforms (Mataric et al. 2007).

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Leveraging Laptop Leveraging Laptop HardwareHardware

• How can we both interest students in robotics, and get them involved at reasonably low cost?

• Need mobility, sensor and software components.

• Idea: Leverage sensors and computing power inside the laptops that they already own.

• 2007 ECAR survey: 73.7% of college students now own laptops.

• Cameras already available in many models, accelerometers on some (Acer, Apple, IBM).

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Our ApproachOur Approach1. Explore the idea of using student-owned

laptops as capable robot platforms.

2. Use on-board hardware (e.g. camera, accelerometer etc.) for sensing and computing.

3. “Just add wheels”, i.e. a motorized base, for mobility.

4. Develop an open source software platform, freely available, to take advantage of this hardware.

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The LapBotThe LapBot

• Prototype hardware / software platform.

• Apple MacBook Core Duo laptop

• iRobot Create mobile base

• Runs (free) Ubuntu Linux.

• Software for two tasks:

• Monocular SLAM using the built-in iSight camera.

• Bump sensing / obstacledetection using accelerometer.

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System Block DiagramSystem Block Diagram

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MonoSLAMMonoSLAM• We use a freely-available monocular (single-

camera) SLAM package (Davison 2003).

• Full 6-DoF SLAM running in real time.

• Requires initialization using known calibration target.

• Image data is acquired from internal iSight camera.

• Grabs frames on the MacBook Core Duo at 5 – 10 Hz.

• 640 x 480 VGA resolution.

• Works qualitatively very well.

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MonoSLAM ExampleMonoSLAM Example

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Bump SensingBump Sensing

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• Access the on-board Apple Sudden Motion Sensor.

• High-resolution, high-speed three-axis solid-state accelerometer unit.

• 250 counts per gravity. Sampled at more than 300 Hz.

• No official API from Apple (yet), but reading data is easy.

• Repurpose the sensor for bump/collision detection.

• Threshold test on smoothed sensor output. > 0.4 g’s is a considered a bump.

• Currently, robot emits an auditory tone when bumped.

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Bump Sensing ExampleBump Sensing Example

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The LapBot in ActionThe LapBot in Action

• Video shows student driving the LapBot manually in our lab building.

• Display support holds screen (and camera) rigidly upright – this aides feature tracking.

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ConclusionsConclusions

• Described and motivated the design of a prototype laptop robot built to leverage hardware that is likely available (or will be available) to students.

• Both MonoSLAM and accelerometer-based bump sensing work well, and run in real-time on laptop processor.

• One of the benefits of using a full laptop instead of an embedded processor.

• Emphasize that all hardware except for locomotion is built into the laptop itself.

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Future WorkFuture Work• Continuing to develop out-of-the-box software

packages for a variety of laptop hardware.

• User should be able to install with minimal effort, i.e. the package has to ‘just work’.

• Trial in a classroom environment.

• Presently, we have a simple proof-of-concept implementation.

• Need to carefully evaluate the feasibility of the approachfor a real classroom.

• Ideally, this would be a freshman college class. K-12 would come later.

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Thank You.Thank You.Questions?Questions?