Electronic Luggage Follower (ELF) - Florida International University
Contents
1. 6 186e 005 5 624e 005 063e 005 m KS Yf6e 005 P Co X 12254e 005 S019 005 1 592e 005 1 130e 005 _5 686e 006 Me 6 795e 008 Figure 31 Drop Test Stress on the Base of the ELF Aluminum Alloy 2014 The second material used to perform the drop test was the Plastic ABS this material past the drop test and did not get any deformation but after the test was perform the base got some weakness zone The zone in read became weak bu the Plastic ABS based did not get any deformation The results following the order deformation displacement were as follows Figure 32 Drop Test Deformation on the Base of the ELF Plastic ABS Gear Analysis In order for the luggage to move in a direction desired the wheels have to be provided a torque to obtain a tangential velocity from the wheels To obtain this torque a motor needs to be connected to the driving wheels The wheels are connected to the motor through a gear train composed in this case of three different diameter gears For the purpose of this problem let s call the gears Gi G2 and Gs The gears specifications are the following No of Teeth Diameter in Maximum Torque in Ibs Gs ag 258 OD Table 2 Velocity Analysis To perform the gear analysis of the system the desired velocity of the luggage and input torque of the system is needed The desired velocity of the luggage is 6 56 ft s This is the measured velocity for a perso2. FLORIDA INTERNATIONAL UNIVERSITY Miamis public research university Florida International University Department of Mechanical and Materials Engineering Electronic Luggage Follower Submitted By Adam Stredel Cesar Nunez Maria V Level Faculty Advisor Dr Sabri Tosunoglu 11 28 2007 Table of Contents TORIS O E ele te ere FIO EE 3 TOPIC ESTE ene Re 5 gis eG eae ed T 5 ENEE 5 FORON TUNIC ONOI TR T 6 leede Gael mI 8 Be EI ROVIO W oine 8 ee ee 9 BE lie 9 MTC ENG UNE CICS ru ean c nr MCN EE 9 IV OS Mle Ee 9 FOI Se KON IRA RE 10 Bee ee tee E 11 welee esseeR aze e E T mU m T TU MT 12 Ra op M M 12 Utrasonie SENSON erorien air e eene ee uu timet ueque 13 MOTOL RM T oa ceses 15 Dalle boast EE 16 Sege 18 Chassis and E EE E 18 SI HO pel Ni Re EE 19 Hazards and GUIS ite ROT TT m QU 21 Engheernng ANGIYS SUMMI Y De E m m a a aaa 23 SOV CO O ea E E A E 29 dT heriral e E 29 Fore Analysis eegene 34 Drop ERN UU UT 4 EE 45 eer e 46 Torque Force EE aone 47 giorereialaateEe ndm TT TM 49 lie SeEOE RODO E 49 Protamine The Past ROW OG aeo tane hen e o Dai elu OOA ec e hats 50 Testing the First Pro Oras 2 n tere ubt Oa uS A stet ida uia 50 Buy t9 IBe EE 51 Testing One Ultrasonic SENSON TTT 52 Tie EE 54 Tovins to Simulate E osos ote rodeo ad No oti reed bad a Arati ais 54 Usine T3v
3. Pulse AID On Convertor Modulation Figure 40 Transmitter Circuit System Draft Once the signal is recorded by the Ultrasonic sensor receiver a Signal amplifier based on 741 Op Amps is used in order to increase the signal frequency After that the signal is used by the PIC16F684 Here the analog signal coming in is transformed to digital in order to quantity it later A programming code if used convert the digital frequency of the input signal into a range number between 0 and 99 as the frequency increase the number becomes bigger Then A Pulse with Modulation is created so that this numbers can be transform into percentage of elapse time for a duty cycle that will be created at 50Hz This duty cycle is totally compatible with VEX Micro Controller so from there on the rest of the program can be written without problems Assignment Distribution Adam Stredel Signature Problem Statement Literature Review Project Statement Failure Modes and Effects Analysis Assembly of Prototype Robot Components Cesar Nunez Maria V Signature Problem Statement Concepts Function analysis Bill of Materials Engineering Summary Analysis Level Signature Problem Statement Literature Review Design Specifications Preliminary Cost Analysis Programming for part
4. AA aT PUL JOU Ton 3SesatrT STE TEUE 398 E3reuro ng SOAS Amar SUHE AA oIpD0EU JOU Ton A n ee 395 asesst BUTE apuen Paje JOU MA Z010 IN Son 210 ap sN H207 AVAL SDAIEUK Spay pue sapo ampeg Engineering Analysis Summary Virtual Parts amp Assembly of the Design The Base Figure 6 of the follower Luggage is an assembly of numerous parts or assemblies The Base structure Figure 7 were all the pieces are located is made of Aluminum 2014 Alloy and contain small structures that keep all the pieces together This structure also have four wholes were the Wheels Figure 8 are placed Connected to the wheels will be the four Motors Figure 9 These motors are connected to the Microcontroller Figure 10 that tells them what to do Also attached to the microcontroller and on the front part of the luggage will be the two Ultrasonic Sensors Figure 11 These are the ones in charge of emitting and receiving the signal that will be later used by the microcontroller For last there are four Batteries Figure 12 connected to the microcontroller in order to give power to the whole system Figure 9 Motor used in the ELF Figure 10 Microcontroller of the ELF Figure 11 Ultrasonic Sensor of the ELF Figure 12 Battery used on the ELF The Upper Part Figure 1 8 which is connected to the base is entirely made of nylon 6 10 of different colors The bigger part of the luggage contai
5. E SYE adhima E a quiass abebbr a 104 SHO OOS abebbn au ubisa usiue uaa allt 104 SAMANS siue uaa au ubrsar palog asco 10 apiaar ta 1082007 Suen Fi A pp at p ele HE D GE Fe Fe be pn ee n n GI Fl D el pel el H Ch Hazards and Failure analysis After all the study cases results and analysis it is easy to conclude that the base must be made of Plastic ABS because of the constant high performance in all the test that it was expose Even though the thermal analysis force analysis and drop analysis gave a safe design with a factor of safety of 2 2 gt 2 the design has to be change in the motors holder zone because of the weakness showed in all the analysis The thermal analysis obtained for the base gave a very good result because it resists the temperature desire With this our design should function perfectly after the modification of the motors holders Since the idea is to produce this luggage and the product will be exposed to falls high temperature and high forces a change must be done on the weakest part of the base before the luggage is physically assembled Another part evaluated were the shelves placed inside the luggage The shelves are safe with a factor of safety of 73 gt 2 which permit a limit of 15 Ib over them without any problem The team idea by using Nylon 6 10 as the material for this structure is that these shelves will be flexible and still hard letting it deform and go back to i
6. before is to follow a person in either a manual or a wireless way Ultrasonic sensors are in charge of the wireless function of the luggage Touch sensors are used to manually drag the luggage Challenges Dragging a heavy luggage causes a strain on the person s body and discomfort too his her day The product being developed will end the discomfort of having to drag luggage all around any flat surface It will also eliminate luggage being left behind or stolen The concept was developed by New York architect Peter Yaedon However his design has not been developed and does not yet met airline requirements The challenges of ELF can be classified in two the wireless design and the easily drag design For the wireless system the challenge is to achieve the physical separation of an ultrasonic sensor Ultrasonic sensors are sensors where the transmitter and receiver work together as a one piece Originally the transmitter sends a signal that bounces in any surface and then is received by the receiver The lap of time in recorded and the distance is estimated Separate this sensor is our biggest challenge Once the physical separation is achieved another challenge appears The sensor should estimate the distance according to the magnitude of the feculence instead of the time that takes the signal to leave and return to the sensor For the easy to drag system the challenge is based on the accuracy of the manual command The user will use a rope t
7. the middle part of the luggage This deformation is produced basically because of the lack of support in the middle region The solution that the team suggests for this deformation is to add to our design an all axis movement wheel that will not affect the movement of the luggage and it will provide the support need it to prevent the failure in the critical zone For the next figures the results follows the order deformation displacement and stress were as follows Model name Base Study name Base Bending Plot type Deformed shape Piot Deformation scale 272 841 Figure 20 Force Analysis Deformation on the Base of the ELF Aluminum Alloy 2014 Model name Base Study name Base Bending Plot type Static displacement Plot1 Deformation scale 272 841 URES m 2 382e 004 2 184e 004 Figure 21 Force Analysis Displacements on the Base of the ELF Aluminum Alloy 2014 Model name Base Study name Base Bending Plot type Static nodal stress Plot1 Deformation scale 272 641 von Mises N m 2 4 371e 007 4 007e 007 7 283e4006 3 651e 006 9 126e 003 yield strength 9 651e 007 Figure 22 Force Analysis Stress on the Base of the ELF Aluminum Alloy 2014 The second material evaluated is the Plastic ABS the Plastic ABS performance was real good comparing to the Aluminum Alloy 21014 The deformation shows in the next figure is very little and because the force applied is greater that the regular
8. three sensors just for receiving the signal The problem was that more than one ultrasonic sensor was needed in order to do this In order to solve the problem with what already had the idea of using touch sensors arrived This idea would help to avoid the robot to go toward a wall but it would not help to avoid it follow a moving object The program was written and worked perfectly Once the other three ultrasonic sensors arrived both ideas will be used That means the robot will work perfectly with the ultrasonic sensors but there will be touch sensors around the base just in case something goes wrong Buying the Parts It was decided to use VEX parts The programming and assembly of VEX was already known and the programming needed to be improved promplly The basic parts we needed to order were included in the VEX Starter Kit Also a Programming kit a battery kit and 5 ultrasonic sensors would be needed An opportunity for obtaining the parts for free arrived Some donation money was being asked to be used for an Engineer woman with an interesting project that could be later presented in some high schools to promote engineering in small kids Luckily after meeting several times with Stephanie Strange the Assistant Director of Recruitment and Retention the donation and the parts were bought An amount of almost 600 was used for these parts Testing One Ultrasonic Sensor The parts were already ordered so in the mean whil
9. 36 Figure 22 Force Analysis Stress on the Base of the ELF Aluminum Alloy 2014 36 Figure 24 Force Analysis Displacements on the Base of the ELF Plastic ABS 38 Figure 23 Force Analysis Deformation on the Base of the ELF Plastic ABS eescccccccccc 0 Figure 25 Force Analysis Stress on the Base of the ELF Plastic ARA 39 Figure 26 Force Analysis on the Inside Shelter of the Ett 40 Figure 27 Force Analysis on the Inside Shelter of the ELF essen 41 Figure 28 Force Analysis on the Inside Shelter of the ELF essen 41 Figure 29 Drop Test Deformation on the Base of the ELF Aluminum Alloy 2014 43 Figure 30 Drop Test Displacement on the Base of the ELF Aluminum Alloy 2014 43 Figure 31 Drop Test Stress on the Base of the ELF Aluminum Alloy 2014 44 Figure 32 Drop Test Deformation on the Base of the ELF Plastic ABS essse 45 meis rov m TEM TH 49 ae Arq U 53 et 53 CIUS iu Uum teu E iiM d UU UM a tase anes 54 FIOI ORO Ausser on Msc IM cM OM I Ee 55 EI 99 FIGURE SO TON Sia er IEN DI EE 59 Figure 40 Transmitter Circuit System DEO qu sce de ueber dt eo uod Pact st ea oi detecte apnd 60 Problem Statement Faculty Advisor Dr Sabri Tosunoglu Team Me
10. al was being received by the ultrasonic sensor That means that the receiver of the ultrasonic sensor won t work until a signal is sent by the same ultrasonic Sensor Analyzing the Inside of an Ultrasonic Sensor It was discovered that the ultrasonic sensor signal must be sent in order to make the receiver on the same ultrasonic sensor record any signal What is being really recorded is the elapse time between the sent and received signal In order to receive an external signal being sent by other ultrasonic one of the output signals must be activated but physically blocked If the ultrasonic sensor located on the luggage is activated it will be sending an output signal that will be interfering with the one being sent by the outside circuit This way as said before the output of the sensor needed to be blocked First Proof of the Theory Several trials were made once the ultrasonic sensor located on the luggage was set and programmed to receive the signal from the out of the luggage sensor The different trials results in a theory The closer the two ultrasonic sensors are the smallest the number received by the ultrasonic sensor located on the luggage is When the two ultrasonic sensors are shifted or not aligned no signal is received so a 99 number as a relation distance time is obtained That is the highest possible number to be obtained This way the robot is able to follow a person that has a sending signal ultrasonic s
11. all the values needed to calculate the power are known and the power required by the wheels is 229 6 ft lbs carrying a maximum load of 70 Ibs Using this power or torque then through gear analysis the torque required by the motor is found The gear attached to the wheel Gs requires a torque of about 230 ft lbs This torque is transmitted to G2 through as force Fs and this force can be calculated using the following equation 2 In this case d is the diameter of the gear and T is the torque within this gear Using this equation the torque through each gear can be obtained 51 58 ft lbs 139 9 ft lbs 229 6 ft lbs The value of Ti is the torque required to move the luggage at the desired speed of 6 56 ft s The motors purchased from VexLabs cannot provide such torque so for commercial use of the luggage and everyday use a higher torque motor is needed Programming of the E L F Pre set of Robot A provisional VEX robot was assembled and simulated it in order to start analyzing the parts we would need and the programming we would be working on Vex parts were used and the robot was assembled as seen in Fig 33 Motion and sensors program is done in this robot to later been applied to the final robot or assembly Figure 33 Programming the First Robot The pre set robot was programmed The idea was to make the robot follow the user in a wireless way Since only one ultrasonic sensor was available we used this s
12. could be placed on the luggage Instead of spending money on buying new ultrasonic sensors that already come with the sensor and receiver separated it was decided to separate the once we already had Vex Ultrasonic Sensors Motor Another important component is the motor that will drive the gears that run the wheels For the luggage we may need two motors to run either the right wheels or the left wheels For the ELF we need the motors to be small light and that provide a high torque and high speed in order to follow a fast walking user This conditions were obtained in a VEX Motor seen in Figure 3 Figure 3 Vex Motor In Table 1 1 the most important specifications of the VEX motor are shown Stall Torque oo nts approximately 4 4 15 Volts Motor life will be reduced Max Min operating Voltage outside the Vex Controller range of 5 5 9 0 Volts 0 21 Ibs Table 1 1 Battery To build the prototype of the Electronic Luggage Follower ELF robotic parts designed by VEX Robotics Design System were used A MEX Power Pack was bought as seen in Figure 4 This includes a 9 6V battery pack and a 7 2V battery pack which for the purpose of this prototype the 7 2 volts is enough AU A e v Figure 4 Vex Labs Power Pack This battery pack can run for about 4 hours on a single charge which is a rough average of the time a person could spends walking around with his or her luggage The power pack a
13. e decide to study the behavior of the ultrasonic sensor available to work ahead of time Studying the possibility of using an ultrasonic sensor just for receiving and another one just for sending the necessity of building a small circuit arrived Theoretically a circuit should be built in order to simulate whatever impulse or signal is sent by the microcontroller or program to the ultrasonic sensor An oscilloscope was used By connecting the output of the microcontroller were the ultrasonic sensor is connected to the oscilloscope we could find the signal sent by the microcontroller to the ultrasonic sensor The microcontroller was found to send an impulse of 5Volts during 12 6us every 56us This can be seen in Fig 34 where the dots represent the impulses and the distance between them is measured to obtain 5 6yus Figure 34 To better understand it Figure 34 is created Here the pulses and the time period of them and between them can easily be seen 5 Volts Figure 35 The idea was to create a circuit able to send this evaluated signal to an ultrasonic sensor connected to it At least two sensors were needed fo test this new theory The Pieces Arrived As soon as the pieces arrived after almost two weeks of waiting we built a testing robot to continue programming The robot as seen in Fig 36 has many differences comparing it to the last one Fig 33 It has no gears it has three ultrasonic sensors on the fron
14. ement wheel and the Plastic ABS Even though the results seem to be good and that the stresses and displacements are minimal for our design we can not allow the base to deform because the upper part would not fit and the whole luggage will lose equilibrium and beauty The other reason for us not allowing our design to deform is because the material we are using is not flexible so the base will not go back to its original shape For the force analysis on the shelves the material used was nylon 6 10 which can resist the load of 15lb force The load is applied to the part and the results following the order deformation displacement and stress were as follows Model name Bottom shelf Study name Shelf Test Plot type Deformed shape Plot1 Deformation scale 117 397 Figure 26 Force Analysis on the Inside Shelter of the ELF Model name Bottom shelf Study name Shelf Test Plot type Static displacement Plot1 Deformation scale 117 397 URES m 5 387e 004 4 938e 004 4 489e 004 4 040e 004 3 591e 004 3 142e 004 2 693e 004 2 244e 004 1 796e 004 1 347e 004 8 978e 005 4 489e 005 1 000e 033 Figure 27 Force Analysis on the Inside Shelter of the ELF Figure 28 Force Analysis on the Inside Shelter of the ELF Differing from the force analysis of the base the analysis of the shelves was successful Even though the shelves is deform its material will allow it to move around without breaking apart a
15. ensor fo measure the distance between the user and the luggage The ultrasonic sensor is started It sends a signal which is received by the same ultrasonic sensor The time between the sent signal and received one is measured by the program and in this way a relation between time and distance is created An idea of using three ultrasonic sensors instead of one arrived If three ultrasonic sensors could be placed on the front right and left of the luggage they could be used not only for distance sensors but also for directional sensors The program would basically search for the smallest distance and the luggage would move in that direction The robot was programmed trying to follow that idea but using the only ultrasonic sensor available A servo was placed on the base of the ultrasonic sensor to allow it to move from left to right this way the sensor was able to send and receive signal on deferent locations The program worked perfectly The ultrasonic sensor was able to search for the smallest distance and go towards it Testing the First Program After several tests a new problem arrived The robot was able to search for the closest object and follow it but that object wasn t necessarily the user of the luggage In some trials the robot just moved toward a wall or a crossing person In order to solve this problem two ideas occur The best solution to the problem was to use one ultrasonic just for sending the signal and other
16. ensor without following a wall or any other moving object Also the robot has as said before three touch sensors programmed to go back and turn in case of contact with anything The last problem to be solved was to know the direction in which the robot should move As said before when the two ultrasonic sensors were not aligned a large number was received then the robot would not know where to go The solution to this problem was to program the three ultrasonic sensors at the same time so that the three signals could be received and the robot would go in the direction of the smallest number received the smallest distance between the luggage and the user Failure of the Theory Once the three ultrasonic sensors could be connected at the same time several tests were done to prove that the theory was truthful Unfortunately when analyzing the collected data from the three receiving ultrasonic sensors could be detected that the numbers were totally random That means that the work done in trying to use two separated systems of ultrasonic sensors was pointless Installing a Manual System As mechanical engineers the idea to make the robot follow a person in a wireless manner was almost impossible An idea of a new system commanded manually was created This idea was to use a flexible handle externally attached to an internal rope This rope would activate one of the two touch sensors located on the sides of the rope These two senso
17. force used by the luggage users the material can be one of the final options The base using the Plastic ABS presents some critical deformation in the front part of the luggage For the next figures the results follows the order deformation displacement and stress were as follows Figure 23 Force Analysis Deformation on the Base of the ELF Plastic ABS Model name Base Study name Base Bending Plot type Static displacement Plot1 Deformation scale 0 228042 URES rm 2 852e 001 2 624e 001 2 385e 001 24Te 001 388e 001 e 001 p 001 ee 001 F3 5416e 002 7 155e 002 4 771e 002 e 2 385e 002 1 000e 033 Y Figure 24 Force Analysis Displacements on the Base of the ELF Plastic ABS Model name Base Study name Base Bending Plot type Static nodal stress Plot1 Deformation scale 0 228042 von Mises Nim 2 6 449e 008 5 911e 008 5 374e 008 F2 150e 008 1 612e 008 1 075e 008 5 378e 007 4152e 004 Figure 25 Force Analysis Stress on the Base of the ELF Plastic ABS The final material evaluated in this test was the wood The material did not resist the amount of load The application in the Solid Works program was not allowed to omit an answer to the base made of wood The base using this material was totally destroyed so the luggage because of the failure in this force test can not be made of wood The last two option remind are the Aluminum Alloy 2014 by adding the all axes mov
18. gure that the base is safe as far as heat concerns The most heated parts are where the wheels will be connected and the rest of the structure is maintained in a low temperature That problem can be fixed by changing the piece affected and by adding some more material in the critical ZONE se Study name Base Thermal Plot type Thermal Plot1 Time step 1 Temp Kelvin 3 743e4002 3 250e 002 Figure 16 Thermal Analysis on the Base of the ELF Aluminum Alloy 2014 The second material used was the Plastic ABS and this plastic by applying the heat was deformed in some little zones As it can be seen in the next figure the deformation were produced where the motors are in other words the deformation is were the max heat is situated but because the motors used are the ones that has the pre requisites need it for the luggage torque power The plastic ABS has pasted the thermal test getting a very similar result comparing to the Aluminum Alloys 2014 The plastic ABS pasted the thermal test Model name Base Study name Base Thermal Plot type Thermal Plott Time step 1 Temp Kelvin B r8ex ns 5 5728005 5 065e 005 4 559e 005 MEET ER E TUS e Get P2027 6 005 4 520e 005 _1 014e 005 m 5 O76e 004 1 198e 002 Figure 17 Thermal Analysis on the Base of the ELF Plastic ABS The last material that will be tested is wood so the next figure will be about wood thermal analysis The wood used
19. lso contains a battery charger and a set of straps nuts and screws to hold the batteries in place All these components are being used for the prototype of the ELF Programming A programming kit from VEX was bought This programming kit includes a cable that connects the robot to the computer via USB to install the programming into the system and a CD with the software needed to do the programming for the system Chassis and Fasteners We also bought a Robot Starter Kit from Vex Robotics as seen in Figure 5 This included a series of parts necessary to build a basic model of the prototype Figure 5 Vex Labs Robot Starter Kit Some of the parts included in this kit and used to build the ELF are as follows e Drive Shaft Bars e Shaft Lock Bars e Chassis Rails e Chassis Angles e A set of different size gears e A series of screws washers nuts bolts Functional Analysis Use ultrasonic sensors to send and receive signal in order to know the orientation of the user Wireless System Turn wheels to be able to follow the user Adapts its velocity according to the user s velocity Use touch sensors to identify the direction taken by the user Manual System Follow the User y Use a mechanism with touch sensor and springs to recognize the forward movement of the user Set off alarm when luggage us separated from the floor Anti theft System Set off alarm when luggage is left behind More than Imin with
20. mbers Adam Stredel Maria Level Cesar Nunez Project Concepts The Electronic Luggage Follower A luggage that will follow the user throughout any flat surface without the need of the user to use force to drag it No effort will be applied by the user in order to carry different load magnitudes Objectives e A product easy to be use and to be manageable by any person e A wireless system made of a transmitter part and a receiver part connected to the luggage e Anoptional way to carry the luggage In case of any problem e A structure and based design to resist load different temperatures and external forces e A luggage with an attractive and innovative exterior design e A security system that the user can be free of worries of his or her luggage being stolen or left behind Form and functionality The product comes in the same sizes as any standard luggage The system inside the bags is resistant to any load or external force The luggage functions with several different sensors ultrasonic sensor and touch sensor These sensors prevent the bag from bumping onto obstacles such as people wall and other things on the floor The form of the upper part of the luggage is made round to allow aerodynamics The based form follows the upper part producing a sense of surface smoothness Inside the base all the components are arranged on the back part in a stable and practical way The functionality of the luggage as said
21. n usage It needs to have a system that allows one luggage to identify the user in order to follow him her It also needs to have a built in security system that prevents the luggage from being stolen or left behind The luggage functions with a battery so that no plug in is necessary It needs to be able to read where there are any obstacles and prevent from running into Them It also needs to recognize when and how it needs to make a turn The luggage functions with ultrasonic and touch sensors These sensors will work to recognize what path the user is taking and at what speed he she is walking The user will have a belt clip or an ankle bracelet with three sensors that will produce or transmit a constant signal There will also be three more sensors that will record this path and speed and send the information to the microcontroller in the bag which will activate the motor to move the bag where it needs to go Design Specifications e length 25 984 in 66 cm e Width 9 842 in 25 cm e Height 18 110 in 46 cm e Weight 22 046 Ib 10 Kg Maximum e Battery Access from the down face of the bag e Assembly Allen hex screws e Battery Vex 7 2V Ni Cad Battery e Run Time About 4 hrs e Drive 4 wheel drive e Wheel Composition Polyutherane e Wheel Diameter 2 756 in 7 cm e Wheel width 0 787 in 2 cm e Steering 360 steering allowed for each wheel e Translate max speed 6 ft s e Material Nylon Casing amp Polyor
22. n walking at a fast pace The input torque of the system is obtained from the design specifications from the VexLabs motor By calculating the desired velocity v of the system the angular velocity of the wheel can be obtained using the following equation D Eq 1 r Where o is the angular velocity and r is the radius of the wheel So after doing the calculations the angular velocity of the wheel is approximately 546 7 rpm Using this value the gear train is analyzed Gear 3 is attached to the same shaft as the wheel so the angular velocity of the gear is the same as the wheel Using the following equation the angular velocity for G2 a2 can also be found as well as the angular velocity of gear 1 con N where n is the speed of the gear and N is the number of teeth of that gear a is a representation of what gear speed is needed and b is the gear with the known speed So the values of the angular velocities in rpm for all three gears are as follows n 109 33 n 182 20 n 546 70 The VexLabs motor used in the prototype provides a maximum speed of 100 rpm at free rotation so the desired velocity cannot be accomplished So with the motor loaded with the gears and adding small weight on the system an input velocity of 50 rpm is assumed Using equation 2 from above the actual values for the system used are obtained and they are as follows rpm n 50 n 83 33 n 250 with these angular velocities the out
23. nd going back to its original position The shelves material Nylon 6 10 pasted the force test Drop Test The drop test was done to the base since that is the part that will be added to what it is commonly known as a regular luggage Also this part contains the most delicate and important part of our design which is the mechanism of the robot The different types of material will be exposed to be drop from a certain height When performing the drop test the luggage is exposed only to gravity force at a height of 39 37 in with an initial velocity of zero The material that were used to perform this drop test are Aluminum Alloy 2014 and Plastic ABS The first material used to perform the drop test on the base of the luggage was the Aluminum Alloy 2014 The next figure will demonstrate that the material Used was not resistance enough to support the weight of the luggage while it is dropped from a certain height The figure shows that the resistance of the material is not good so the test evaluated by the Aluminum Alloy 2014 failed The results following the order deformation displacement and stress were as follows Figure 29 Drop Test Deformation on the Base of the ELF Aluminum Alloy 2014 Figure 30 Drop Test Displacement on the Base of the ELF Aluminum Alloy 2014 Model name Base Study name Base Drop Test Plot type Plot Plot step 1 time 16 6587 Microseconds Deformation scale 1012 05 URES m 5 748e 005
24. ns two movable Shelves Figure 1 9 that allow the user to have a better use of the space In order to connect the small and big pats that compose the upper part of the luggage two hinges are used To attach the upper part to the bottom part of the luggage five fastener screws are used Figure 13 Upper Part of the Luggage Figure 14 Inside Shelves of the ELF Figure 15 Inside Shelves of the ELF Study Cases Thermal Analysis he thermal analysis is made to the base and the battery The reason is that the base is the most exposed to heat since the mechanism might produce some heat The Battery when exposed to heat might be dangerous so a heat analysis is done on this part too For this analysis 25 C is used as room temperature and a heat power of SOW is also used The team performed this thermal test with different types of material some of them failed and some of them did not The materials that passed the thermal test were the option of the material that can be used in the elf so the luggage will be safe enough to be in any regular temperature The material used to do this test were aluminums plastics and wood The results obtained in each test for each material as follows The following figure shows how the aluminum alloys 2014 past the thermal test The part covered by the blue color is the part that was not affected by the heat produced by the motors and as hotter the piece as redness the color This indicates on the fi
25. o drag the luggage By using touch sensors the rope will be an activator for motion As the rope is moved to either left or right the luggage will rapidly move to the corresponding side so that no force is required by the user The biggest challenge in this system is to control the forward and stopping motion As the user pulls the rope a little the sensor must be activated and the luggage must go forward Clients intended This product can apply to anyone and everyone that has the need of dragging a luggage on a flat surface However to be specific the follower bag may be directed exactly to women old people kids and lazy or busy people The objective is to drag a luggage using no force at all that is why our clients are based on weak people Busy people are also taken into account since most of the time they have their hands busy whether it is with cell phones books or anything else Literature Review Books e Choudhury Maroof Haider A multi sensor sonar system for indoor range measurement as a navigational aid for the blind Green Library General Collection 2003 e Jorge Blanch Control of mobile robotic platforms by handheld devices Green Library General Collection 2003 e Helmers Carl T Robotics age in the beginning Ed Hayden 1983 e Robillar Mark J Microprocessor Based Robotics Ed Howard W Sams amp Co Inc 1983 e Patel Patt Introduction to Computing Systems Ed MacGraw Hill 2004 Text b
26. ooks e Joseph Shigley Charles Mischke and Richard Budynas Mechanical Engineering Design 7 Edition New York NY McGraw Hill 2004 Internet Articles e Carlo Innocenti Forward Kinematics in Polynomial Form of the General Stewart Platform Journal of Mechanical Design 123 2 2001 http scitation aip org getpdf servlet GetPDFServlet filetype pdf amp id J MDEDBOOO0 23000002000254000001 amp idtype cvips gt e Neng Tung Liao and Jen Fin Lin A New Method for the Analysis of Deformation and Load in a Ball Bearing With Variable Contact Angle Journal of Mechanical Design 123 2 2001 http scitation aip org getpdf servlet GetPDFServlet filetype pdf amp id J MDEDB000123000002000304000001 amp idtype cvips gt e Yangmin Li and Yugang Liu Real Time Tip Over Prevention and Path Following Control for Redundant Nonholonomic Mobile Modular Manipulators via Fuzzy and Neural Fuzzy Approaches Journal of Dynamic Systems Measurement and Control 128 4 2006 lt http scitation aip org getodt serviet GetPDFServlet tiletyoe podf amp id J DSMAAO00128000004000753000001 amp idtype cvips gt Website e htto www yeadon net yeadon support projects projects html e htitp en wikipedia org wiki Sensor Project Statement The Electronic Luggage Follower It is aluggage that by using sensors will follow the user wherever he she needs to go to make life time a lot more comfortable The product needs to be practical to huma
27. opylene Base Robot Components There are a series of components that need to be taken in consideration while building an automated luggage The parts may include sensors micro controller motors gears batteries Nylon for the casing among other things All these factors are very important in putting this luggage together Wheels Wheels need to have very low friction so that there is no resistance while the ELF follows the user Polyurethane wheel are used similar to those on roller blades as shown in Figure 1 The polyurethane composite is mounted on a hard plastic called polypropylene These wheels can be used in any flat or almost flat surface Figure 1 VEX Polyurethane wheel For our purpose we could use a 2 756 in diameter wheel Ball wheels which can rotate in any direction are also used for the back part of the luggage These wheels may help us distribute the weight of the luggage and its load without interfering on the direction of the robot or the resistant due to friction Ultrasonic Sensor Now there is what could be the most important part of the luggage the wireless system The system mainly contains three ultrasonic sensors receivers and three transmitters the required circuit to make it work and a compatible micro controller The main part of this system is the ultrasonic sensors used since the system is designed around these sensors so we needed to carefully choose on what type of sensors
28. osMaIcroconDtrollets uoc ee ee 55 Analyzing the Inside of an Ultrasonic Sensor 56 e te EEN ee 56 Failure ofthe Eeer 57 TIastaiimo a Manual SyS teM E 57 A A EE 58 EECHER EE EE EE 6 Table of Figures Figure 1 VEX Polyurethane Whe ee 13 Figure 2 Vex Robotics Ultrasonic Range Finder sse eee ennt 15 ROUSE Ru MOTO TH 16 Figure v Vex Labs POW Er POCK ee eege Ee 17 FOEI VEX LODS RODOS eddy MM 18 PIOUS BOSS Ee 24 FIOUTET BO CSUCS ONS ELF ondoen PH 24 Figures ee Eet E 24 let enel E e Nee EE 29 Figur 10 MICTOCONTFOUEl Ol INE ELF Reesen 25 FONS TTUN ONCS Snr ONNEEN srauni r ta e teet Eta etae eet dtes 26 Figure 12 Battery used on the ED ues tee desta do ette ta Ee reae Eg S Pelea EP nasa Erogo Rea Made ouf uas 26 Figure IS Upper Ran Ol med e ere EE 27 ele UE e Ge SICIV of Ihe EE 28 Figure 15 Inside Shelves or the BER s veo rep E co e teer tha ated enitn 28 Figure 16 Thermal Analysis on the Base of the ELF Aluminum Alloy 2014 30 Figure 17 Thermal Analysis on the Base of the ELF Plastic ABS ccccccccceeccceeseccceesecseeeeess 3l Figure 18 Thermal Analysis on the Base of the ELF wood 32 Figure 19 Thermal Analysis on the Battery of bet 33 Figure 20 Force Analysis Deformation on the Base of the ELF Aluminum Alloy 2014 35 Figure 21 Force Analysis Displacements on the Base of the ELF Aluminum Alloy 2014
29. ously the analysis succeeds since there is no portion of the battery with a high temperature This means that the battery will be safe on an ambient temperature of 213 15 Celsius As we can see in the next figure the battery past the thermal test The results obtained were Model name vex BDcellpack solid 1 Study name Battery Thermal Plot type Thermal Plot Time step 1 Temp Kelvin 6 006e 001 006e 001 6 005e 001 6 005e 001 6 004e 001 003e 001 6 003e 001 6 003e 001 5 002e 001 5 001e 001 5 001 amp 001 m 6 001e 001 6 000e 001 Figure 19 Thermal Analysis on the Battery of the ELF Force Analysis he force analysis is made on the base and the shelves since these are the parts that will receive or resist the higher load The base will support the whole luggage which we think will be approximately 50 Ib The shelves will contain clothes shoes etc so they should be able to rest more than 5 lb each For the force analysis on the base 7Olb force is applied to the part The load was exaggerated in order to have a stronger luggage that can carry some times some extra weight The force analysis is divided in three parts deformation displacement and stress that the force analysis will be express in three different figures Aluminum Alloy 2014 is the first material to evaluate for the force test on the base of the ELF The following figures shows that the aluminum alloy 2014 force test failed by deformation in
30. out receiving signal OFS cele LOrE LIE ZOLL OF Srl ZU ctt A082 ZO ZU 075 701 ZUdL OL L t rE ZU L ZEE 2Z e E Offers Fears Zip Ora Far ur rd Faris r2 Of Sabie ZU ZU Cd 2Z c3 ZOLL ZU EIS Orla ZU d Others md S 208 ZU lt ZU Zb ZDF ZUdGik Ofer Z ce ADELE Ofer fOr are ZU Zoe ZI OFS A0fB cel zz auau j2Sfo14 ZOLL ZO Orel e LI Bum LS y Se y mp ES Jul DG vo JE 2l E xD amp MODO Eo MIE o Jan 3 0 L AWENE 0 o Ju E KDO co ech 3 0 L Ju tL o EL JE Qi zm OL 22D 8 MOOD 9 COH az OM 82 0208 D moo Or Jo B HoE Dz An 02 vu OZ LOM D 00 OF Ju d vm a JE G3 KBG LONON 03 MOO 08 031 02 MOO le 2020 DOL OOL A LOMI D OO DOL Jeu DL MOOL A LOZI OS HOOL DOL LOLH KDO L Aen a KOOL 21 LHZ 3 z pu o o ZG ER 3 3 9 EC TT NV AU WEE AE NK NI NI DS WI NEI WE zen F Lieka deers BIG i RICH ee O OO BIO RICH BIO BUER BIO zen HEY uoneziund une Did Jo fie moo Buysa WSIUEW Sala Ja ssauapie WSIUEU aal Ja ssauantiaaq3 WSIUEWS Alyy Ja Buljsa abebbr ayy Jo saruouobr fiquias s wy pue Jenae au Jo SFU eH abebbn au jo Busa uoneziuurdr pue Bursa Onpa aur ue Jr laabo WSWEYSAls pue abebbnr ajquiass g abebbn pina WSIUEY I au a utes abebbn yo sanausau abebbrr jo amang abebbn au ayqwassy S EURIELY 24 IS fing YOnpOlg Eud 40 Buguassy USIDOLL2SPO
31. put velocity of the system is approximately 5 99 ft s These values prove that the motor used can provide enough velocity to move the system at about 6 ft s However it is very important when working with rational moving parts to check that there is enough torque on the system to cary a large load and still travel at the desired speed Torque Force Analysis In order to get the luggage to start moving a great amount of torque needs to be provided To start off the coefficient of friction between the floor and the wheels needs to be found For the calculations of this luggage the coefficient of static friction between rubber and concrete was found The coefficient of static friction is used because the system is at rest The value of the coefficient of friction is 1 0 Once this value is chosen then the friction force between the wheels and the ground can be found with the following equation F Ab Eq 3 Where Fr is the friction force u is the coefficient of friction and Fn is the normal force The friction force is the force needed to get the luggage fo start moving This force can be plugged into the Power equation The power equation is a function of work and time B Work Time P Eq 4 however the work required by the wheel is unknown but it can be found by using equation 5 W Force x Dis tan ce EC plugging equation 5 into equation 4 the power equation becomes F Dist SE Force x Velocity Eq 6 Time Now
32. rs will be located on the top part of the luggage After that the rope would pass through two pulleys in order to make the rope be parallel to the next system This next system would be made of a flat surface were the rope will begin connected to two springs that will keep the flat surface against the touch sensor so this one can be always pressed The idea is that as soon as the user pulls the rope a little the switch will be released and the robot would be programmed to move forward This will prevent the user to carry any load all the work will be done by the robot Circuit Analysis In order to use a wireless system as desired two separate circuit must be done One circuit will take care of providing the Ultrasonic sensor transmitter with the power and imput signal required see Fig 39 The other circuit will adapt the signal received so that it can be used by the VEX Micro controller see Fig 4 9v Power Frequency Conditioner Generator 9v DV 9v Figure 39 Transmitter Circuit System Draft In Fig 39 can be seen the 9V battery that provides energy to the frequency generator and the ultrasonic transmitter at the same time A Power Conditioner is placed so that the voltage can be reduced to 5V before entering the Frequency transmitter the frequency transmitter used works at 5v The frequency transmitter will create a sine wave of 40 KHz that will be sent by the Ultrasonic transmitter PIC16F684
33. t one touch sensor was placed on the back and other two touch sensors with higher precision were placed on the sides of the robot Figure 36 The idea was to build it fast and useful for programming The design will later on be changed by the rest of the group Trying to Simulate the Circuit In order to simulate the circuit that will allow an ultrasonic sensor to work without a microcontroller a signal generator was used Figure 37 This apparatus was able to generate 5 Volts every 56 us The test failed and one ultrasonic sensor was damaged The problem was that the signal generator wasn t capable of producing the 5 Volts during 12 6 us as in Fig 34 instead a continuous period of 56 us of signal was produced as seen in Fig 38 Figure 37 5 Volts 3 56 us 56 us Figure 38 Using Two Microcontrollers The most important thing to know is if The theory of using one ultrasonic sensor to send the signal and another one to receive the signal would work The circuit must be created to make this possible so took the decision to use a microcontroller a battery and an ultrasonic sensor together as the circuit This would let me work with two ultrasonic sensors separately as wanted A program was written for the separated new microcontroller so that the ultrasonic sensor could be continuously sending the signal There was another problem When tried to retrieve the distance information with the robot no sign
34. ts original position with no problem he last instrument evaluated using Solid Works was the battery The design is safe since it passes the thermal analysis which was the only one done on it because of its importance in the part The battery will not have any other problem because it will be situated inside the base which is the one that absorbed all the load that can be apply on the luggage GUTE Od 124E wajo Tamod ou J0 TRUSTS OH EUSI ou puac pos wossad eeng pug 40u saod age ATTEIMEUIOINE xq4044 EE DEE eg JO al aa BUE Au a pueH JOU paa r m TA sue Hey ag moumg Email Jean Ian Ape Woy and opp Ja squ s 1040F yere ATE DOLL ra SUP Sua Tan JOOP anh o T WO mam Ap IN Eua1e IW Jean Ian ISISA IEUE 3 RU SAN Se DOLL qa SUP Sua SE Tear 331 AA anh T mee HEL PIPE H Hae 0u pp Vn TWO aM Ap IN SUOTEpuaumuo22 peal aL SIUE Dapp SIE EU 32404 j321103 28000 26310 mA aSeSStrT en oe SE jar ege Sousa cos ee paya SIR EU 32104 IO GO nt reng pot 308 TAA TB M pe pi TTT EE peo amp aeam IL PGE One Le 26310 WMA aseSStUT Bumuaq wog NE2Jq Taur SIR EU 3240 EHIE Sung Zem seld mae Liers amare ea amang panog SUUE A appuen aq AEW asEsBtrT GUTE IO 398 E3rpeuro ne spp me Ode ameg AMIN 32407 SUITE apuen JOU Tan asesstrT SUEI 04 age E2T euroqtie 10A Ja o ruo3 o423Tu1 WO Emig BUHE jA 91006 JOU Tan asesstrT Eust ou JO tamod oN STSAJEUE 398 E3reuo ng spa Amar SUE
35. was treated with some painting nonflammable to reduces the risk of any heat accident the team was expecting another answer for the wood thermal analysis but the wood after treated got better results that the Aluminum Alloy and the Plastic ABS during the thermal test The following figure shows that the values obtained by the solid works application in this test are better than the other materials results The wood past the thermal test and is the first option in thermal analysis Model name Base Study name Base Thermal Plot type Thermal Plot Time step 1 Temp Kelvin 1 739e 005 1 594e 005 1 449e 005 1 305e 005 DGUe Oz Sallis e 004 a al 95 811e 004 74 364e 004 2 947e 004 m 1 470e 004 2 358e 002 Figure 18 Thermal Analysis on the Base of the ELF Wood To conclude the performance of this thermal test the best material was the wood because is has less conductivity than the other materials used to perform this test Also the base is getting the same critical zone for all the material used during the thermal test The design of the motors holders has to be change in order to obtain a very trusty base of the luggage in any thermal condition Performing the same thermal test to other pieces gave us more confident in the material and the products that the team selected to use in the ELF For the thermal analysis of the battery a temperature of 213 15 Celsius is applied to the whole surface of the battery Obvi
36. we apply to our design This same system could have been done in a similar way but using infrared sensors instead of ultrasonic sensors James B Bonner from the California State Science Fair in 2005 conducted an experiment where he attached the two sensors to different robots to find out which sensor gave a more accurate reading ultrasonic or infrared He tested on shape size and dimension for each of the two The results of the experiment provided that the ultrasonic sensor had better accuracy due to the fact that the infrared sensor had problems reading distances greater than 30cm Also the robot carrying the infrared sensor took longer stopping than the one carrying the ultrasonic sensor So based on this experiment and finding other opinions from FIU faculty members we decided to use ultrasonic sensors At the beginning it was thought that the normal or common ultrasonic sensors could be used and since most of the parts were used from VEX Company VEX Ultrasonic Sensors were purchased see Figure 2 OUTPUT Figure 2 Vex Robotics Ultrasonic Range Finder This sensor comes standard as an analog output ultrasonic sensor Vex sensors are maid as a one piece sensor This means that the transmitter and receiver are located in the same board as seen on the figure 2 For the purpose of our project these ultrasonic sensors must be physically separated from each other so that the transmitter could be placed on the user and the receiver
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