TumblerEvaluationLab < Main

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<span style="color: #7a4707; font-family: 'Courier New', courier, monaco, monospace; white-space: pre;"> _Measurement requirements:_ </span>

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<span style="color: #7a4707; font-family: 'Courier New', courier, monaco, monospace; white-space: pre;"> __%BLUE%Measurement requirements:%ENDCOLOR%__ </span>

<div id="_mcePaste"> _Measurement Set 1:_ </div> <div id="_mcePaste"> _1. Measure the dimensions of the Tumbler Chassis._ </div> <div id="_mcePaste"> _2. Measure the wheel radius._ </div> <div id="_mcePaste"> _3. What are the overall dimensions of the robot (wheels and chassis). Include a_ </div> <div id="_mcePaste"> _sketch or image of the top view and side view of your robot with dimensions._ </div> <div id="_mcePaste"> _4. Determine the position, shape and size of the polygon of support (PoS) when_ </div> <div id="_mcePaste"> _the robot is at rest on a horizontal surface and sketch this as accurately as you_ </div> <div id="_mcePaste"> _can._ </div> <div id="_mcePaste"> _5. Record and display all these measurements in your lab notebook._ </div> <div id="_mcePaste"> _Measurement Set 2:_ </div> <div id="_mcePaste"> _1. Determine the centroid of the chassis._ </div> <div id="_mcePaste"> _2. Approximate weight of the robot based on the component weight list below._ </div> <div id="_mcePaste"> _3. Determine the center of mass (CoM) of the robot using one of the methods_ </div> <div id="_mcePaste"> _covered in class. (You may want to use the component weight information_ </div> <div id="_mcePaste"> _below)._ </div> <div id="_mcePaste"> _4. Determine what proportion of the weight is supported by each of the wheels._ </div> <div id="_mcePaste"> _5. Record and display all these calculations and measurements and comment on_ </div> <div id="_mcePaste"> _your structure given this information.Measurement Set 3:_ </div> <div id="_mcePaste"> _1. Determine how fast your tumbler is capable of travelling based on the motor_ </div> <div id="_mcePaste"> _information below and the material covered in class. Document your_ </div> <div id="_mcePaste"> _calculations._ </div> <div id="_mcePaste"> _2. Using the measured tracks, evaluate the top speed your tumbler (at least_ </div> <div id="_mcePaste"> _three measurements). Explain any discrepancy._ </div> <div id="_mcePaste"> _3. Record and display these calculations and measurements and comment on_ </div> <div id="_mcePaste"> _any discrepancy._ </div> <div id="_mcePaste"> _Measurement Set 4:_ </div> <div id="_mcePaste"> _1. Using the CoM and PoS, determine the maximum angle of inclination on_ </div> <div id="_mcePaste"> _which your robot will be stable._ </div> <div id="_mcePaste"> _2. Evaluate this by determining the angle experimentally. Start at 10 degrees_ </div> <div id="_mcePaste"> _below your predicted angle and make measurements at 5 degree increments._ </div> <div id="_mcePaste"> _3. Work out using the RMF material from class whether your robot (the motors)_ </div> <div id="_mcePaste"> _have the capability to drive up its maximum stable slope (assume velocity_ </div> <div id="_mcePaste"> _from 1 and a=v/2 m/s_ </div> <div id="_mcePaste"> _2_ </div> <div id="_mcePaste"> _)_ </div> <div id="_mcePaste"> _4. How many motors would you need to drive this slope?_ </div> <div id="_mcePaste"> _5. Record and display your calculations and measurements. Comment on your_ </div> <div id="_mcePaste"> _conclusions._ </div> <div id="_mcePaste"> _Measurement Set 5_ </div> <div id="_mcePaste"> _1. A principal objective of the tumbler is to flip over (tumble) when driven into a_ </div> <div id="_mcePaste"> _wall: Verify that your tumbler will flip over and can continue to drive after a_ </div> <div id="_mcePaste"> _flip._ </div> <div id="_mcePaste"> _2. Use one of the storage boxes as an obstacle, placed against the wall. What_ </div> <div id="_mcePaste"> _happens when the tumbler is driven against it. Document and explain._ </div> <div id="_mcePaste"> _Measurement Set 6:_ </div> <div id="_mcePaste"> _1. Experimentally determine what point on the chassis is the center of rotation_ </div> <div id="_mcePaste"> _(CoR) for the robot. Is this the centroid or CoM? Explain._ </div> <div id="_mcePaste"> _2. Skid-Steering relies on wheel slip, which can be unpredictable, and the CoR_ </div> <div id="_mcePaste"> _may not remain stationary with respect to the ground. Determine by_ </div> <div id="_mcePaste"> _experimentation if the CoR translates during repeated 360 degree rotations_ </div> <div id="_mcePaste"> _and whether this translation is predictable._ </div> <div id="_mcePaste"> _3. Document and display your measurements and calculations._ </div>

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<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">Measurement Set 1: </span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">1. Tumbler Chassis Dimensions </span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"> Length = 204 mm</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"> Width = 255 mm</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">2. Wheel Radius = 65 mm</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">3. Tumbler Overall Dimensions </span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"> Length = 274 mm</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"> Width = 307 mm</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"> Height = 122 mm</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">4. The polygon of support is rectangular, located in the area of the wheels facing the main chassis where the wheels tough the ground</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"><img width="800" alt="" src="%PUBURL%/Main/FRCV-CISC3600S13Group9/Polygon_of_support.jpg" height="597" />Approximation of the polygon of support<br /></span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">Measurement Set 2:</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">1. Centroid of the chassis is </span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">2. Total weight of tumbler = 1362.98 g</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">3. Here is sevral ways to calculate the central mass:</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"><img width="580" alt="" src="%PUBURL%/Main/FRCV-CISC3600S13Group9/central_mass.png" height="351" /><br /></span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">W use the second method: The center of mass was determined by balancing the tumbler on the eraser of a pencil</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"><img width="640" alt="" src="%PUBURL%/Main/FRCV-CISC3600S13Group9/CoM.jpg" height="478" />Image of where the center of mass was determined to be<br /></span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">4. The proportion of weight for each wheel</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">5. After determining the measurements of the tumbler, it was found that the tumbler is a back heavy robot. Having the center of mass toward the back</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">may lead to problems when it comes to overcoming steep inclines, but that remains to be seen. </span></span>

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<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">Measurement Set 3:</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">The tumbler was found to travel a distance of 497.9 cm in an average time of 6.7 s (average time found after three tests). The distance </span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">was determined as the two closest points of the two pieces of white tape, i.e. the inner sides of the tape. The fronts of the wheels were placed</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">on the inner side of the tape, and the end of the test would be called when both front wheels cross the inner side of the other piece of tape.</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">First test: 6.8 s</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">Second test: 6.6 s</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">Third test: 6.9 s</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">1. The tumbler is capable of traveling at 74 cm/s</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">2. The top speed of the tumbler is 80 cm/s</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"><img width="400" alt="" src="%PUBURL%/Main/FRCV-CISC3600S13Group9/Track.jpg" height="299" />Drawing indicating the start and finish</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">Measurement Set 4:</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">1. Determined maximum angle of inclination = 45 degrees. This was determined by tilting the tumbler on it's rear axis backwards until the center of</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">Mass passed the polygon of support, then using a protractor to measure the angle. </span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">2. It was found after experimentation that the tumbler flipped at an angle of 40 degrees.</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">3. The robot would have the ability to drive up it's maximum stabel slope. </span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"> Motor RMF = .96Nm x 11.38rad/s = 10.93</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;"> 1.36298kg x (.37 + 9.8 x sin(40)xl) = 9.24</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">4. One motor would be needed for this slope since one motor has more RMF than the robot.</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">Measurement Set 5:</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">1. <img alt="" src="%PUBURL%/Main/FRCV-CISC3600S13Group9/Tumbler_wall.mp4" />The tumbler was able to flip when it was driven into a wall, and continued to function.</span></span>

<span style="font-family: 'Courier New', courier, monaco, monospace; color: #7a4707;"><span style="white-space: pre;">2. <img alt="" src="%PUBURL%/Main/FRCV-CISC3600S13Group9/Tumbler_Obstacle.mp4" />The tumbler, when encountered with the obstacle, was still able to flip.</span></span>

-- (c) Fordham University Robotics and Computer Vision
This topic: Main > FRCV-CISC3600S13Group9 > TumblerEvaluationLab
Topic revision: r3 - 2013-02-18 - DavidWalsh