General Robotics

General Robotics LEGO Rover Design Workshop 2000 Michael Rosenblatt

General Robotics Contents Analysis of task, based on provided information. Designing good robot platforms for adverse terrain. Control “Smart Mechanisms”

General Robotics Analysis of Provided Information Primary Paths Zone by zone analysis Alternate paths Failure cases

General Robotics Primary Path

General Robotics Zone 1: Start Position Start orientation unknown Free space is approximately 10” x 14” Robot must be able to turn agilely in this space No significant terrain features

General Robotics Zone 2: Boulder Field Ten (10) or eleven (11) medium sized boulders Spacing 3” to 5” apart Height appears to be up to 1.5 inches Robot will not be able to drive in between

General Robotics Zone 3: Downhill Grade Slope is approximately -4 / 15, or 26% downhill grade. Appears pretty smooth, small (perhaps 1”) ledge at bottom.

General Robotics Zone 4: Narrow Passage First narrow passage Six (6) inches wide Steep slope on right End of world on left

General Robotics Zone 5: Steep Climb Slope is 4/7, or.57 % Not smooth, ledges Ten (10) inches wide “Death” drops on both sides Steep approach angle Steep break-over angle break-over angle = The supplement of the angle of the slope. minimum break-over angle = The smallest angle your robot can handle without bottoming out.

General Robotics Zone 6: Plateau Appears to have three, 1” slabs of rock Enough space to drive between Don’t waste time here

General Robotics Zone 7: Second Downhill Grade Slope is -4/10 or 40% down slope Steeper at top Class 2-3 terrain (can roll through) Negative terrain features Narrow (5 inches) at bottom “bridge” section

General Robotics Zone 8: Turning Section Apparent 140 degree left turn Rough “Class 3” terrain “Death” drop on outside of turn

General Robotics Zone 9: Final Ascent Gradual slope Nine (9) inches wide No notable terrain features visible from data

General Robotics Design Matrix

General Robotics Alternate Path 1: Canyon

General Robotics Alternate Path 1: Bridge Layer

General Robotics Failure Cases Robot is in control, but it is clear you cannot execute the path you have planned. Robot has mechanical failure (i.e. wheel falls off) that is crippling but not fatal Robot has fatal mechanical failure Robot has fatal driving error

General Robotics Failure Cases

General Robotics Designing Good Robot Platforms for Adverse Terrain Drive trains revisited Differential drive configurations Center of Gravity Mechanical Robustness Suspensions Testing

General Robotics Drive Trains Revisited Drive trains up to this point have demonstrated good control These drive trains need to handle high- torque situations Back driving Foreign objects Weak links

General Robotics Differential Drive Advantages in steering What happens if you lose a DOF?

General Robotics Center of Gravity Masses –Handy Board –LEGO motors Separate battery from board Consider CG in relation to length and width Traction –Biased-end design

General Robotics Mechanical Robustness Masses are securely fixed in place –3M Double sided foam tape Internal forces are supported Structure can handle odd forces No parts sticking out

General Robotics Suspensions May help with terrain tracking 1st: Wheel/track suspension (uses squishyness of wheels, span of tracks 2nd: Active Dampening Suspensions –Tube things in kits –LEGO shock absorbers –Random foam, springs 3rd: Passive suspensions –Rocker-Boogie suspension

General Robotics Testing Torque Tests Hill Tests Various terrain Ground clearance Approach / Break-over / Exit angle Actual runs on real terrain

General Robotics Control Robot has 1st person perspective Pilot has 3rd person perspective (sometimes occluded) Where to put intelligence? Autonomy?

General Robotics Control: Robot Intelligence Robot has encoders, takes go(int inches), turn(int degrees) Robot has ground sensors (feelers) to abort command when robot may go off an edge Robot has inclination sensors (mercury switches, rolling ball inclinometers, accelerometers) to detect rollover danger Robot has internal sensing to detect use of special functions, or self-diagnostics

General Robotics Control: Robot Autonomy Robot has autonomous functions to deploy equipment Robot can autonomously navigate occluded areas (i.e. wall following) Robot can automate compounded functions such as expanding

General Robotics Smart Mechanisms Mechanisms that compound DOFs –Can do different things depending on which way turned Release mechanisms Expanding Mechanisms Locking Mechanisms –Can lock an expansion or an appendage into position me (and other TAs) for consulting

General Robotics Neat Ideas Marsupial Robots –Robin Murphy, USF Shape Reconfiguring robots –Inuktun.com Asymmetry NASA Rovers Current off road vehicle examples –Land Rover –Jeep –Hummer –The Animal (ok, old) –Other Toys

General Robotics Questions?