AHRC Mascot Robot

Test for file sharing site

2006-10-31T08:49:00.000-08:00

The link below shows a forum and file sharing site set up for online collaboration in the Mascot project. Try it out and provide your opinion please.

http://www.thinkcycle.org/tc-space/tspace?tspace_id=65434

Telescoping Lift

2005-12-07T12:41:00.000-08:00

telescoping lift

Here is a Paint-hacked drawing of the telescoping lift I was talking about. This one uses 1/2" aluminum angle and goes to 14".

I suppose it can be scaled up and modified to elimiate the sliding metal contact, or even some real bearing pads will suffice. It can probably be done with 1" aluminum square tube from Home Depot.

Actuated using cables that tie each stage(in this case there's only one and a half) to the one before it, so a big winch can be used to raise it.

It's more work than drawer slides(which can probably be used in conjunction with the design) but I think it will be much lighter for a given size/height, and no "screwy" components.

Does anyone know what this is actually called? I have seen it on several ceiling service lifts and a few forklifts. Most of them actually did use anchored cables instead of nested cylinders.

From: Team Test Bot

New Frame

2005-11-23T05:59:00.000-08:00

new frame

Well after a long "quiet" period in the mascot activities, we've begun to make some new changes to the design. On the previous RBNO, Mike Lynch brought in some new castors and a couple were added to the CAD files. (you can see one of them here)

Previous attempts to intrest the group in using an "umbrella" baby stroller for the frame, failed. Although this design was light and "ready made", perhaps it was percieved as, well, baby stuff.

So we've got a new frame design, based on the previous design, using 1" square steel tubing and flat plate. The motors were re-oriented to take advantage of the boss cast into the motors (that prevent them from turning around the shaft). The location of the castor wheels were widened for stability. I've included PDF drawings of the frame parts here:

The units are in decimal inches and disregard the 3 decimal places.

gusset
frame01
frame02
frame03

If you're not familiar with machinists tapes, a decimal inch is divided into 10ths instead of the archictural 1/4qtrs, 1/8ths, and 16ths. The first decimal place is 10ths of an inch, the second is 100ths, the 3rd 1000ths. You can ignore the 3rd decimal place for our purposes.

Slide Actuation for Height

2005-11-23T05:57:00.000-08:00

accuride 3601 - 28

During the discussion about gaining height and adding "transformer" style unfolding, Dale Heatherington mentioned using drawer slides. I managed to find sample slides from Accuride, they donated model 3601 which is one of their heaviest slides. Two of them will hold 273 lbs and move smothly. I propose using just one of them for the mascot as they are so heavy and strong. There are other offers of slides in the wings and I hope they are better for our purpose, because of the 3601's weight. See the specs , 3601, web

The extended length is 57" and the closed length is 28".

Base with 3601 slide

2005-11-23T05:50:00.000-08:00

base with slide

This image shows the base with the slide extended. It reaches 69" tall. All of the extension would not be available after adding a ball screw type extender so this example is exaggerated in height by 4 to 6". Still, five plus feet is an impressive height. And that doesn't include a head.

3601 Slide Closed

2005-11-23T05:49:00.000-08:00

3601 slide closed

The size of the closed bot with the new slide bothered me some. The bounding box shows the total envelope as 9x28x22. Would someone measure their trunk and report if this is too big?

There's also a problem with the distance between the motors. The slide wont pass between them when closing. The interference is about 1/4". I'll have to double check the models with the actual motors to see if I left myself any spare. As I recall, the motor connectors are in the rear area, and wiring space will be needed there. We might be able to widen the frame an inch to accomodate this problem. As you will recall, we set the width to be 24" in order to pass through the smallest doors. Standard doors are 28" with 26" being a small door and 32" a large door for moving furniture through and such.

Max Headroom

2005-11-23T05:40:00.000-08:00

maximum space for head

When the bounding box is added to the extended slide, and shortened to fit around the motors when closed, the image above shows the results. There is space for torso bracing. I'll address that after feedback on this current design comes in. My biggest concern about this design is it's weight. I coudn't say at this point if it's going to be closer to 50lbs or 100lbs. If we change to aluminum, we'll be alot happier with the weight, but welding aluminum is a very different animal, and I don't have a volunteer. The slide is steel and very heavy. I'm not aware of any aluminum slides. Perhaps we should follow Dale and Eric's leads and start using more wood and plastic. It wouldn't be a disaster if we wound up with a heavy bot. We can always make another one. We should avoid this error however if we can. Please comment and I'll adjust the design according to your feedback.

2005-11-23T05:39:00.000-08:00

model / sketch overlay

This is a crude overlay example from the sketches we created earlier. This provides some visual cues to help visualise the finished shape for the Mascot.

"I don't have a pen"

2005-07-25T10:40:00.001-07:00

Finally I have a chance to pick back up on the Mascot Project. I'll start where we left off by publishing the sketch exercise we did last.

Amid scoffs of "it will never work" and " I don't have a pen", we did a brainstorming design exercise where individuals draw their concepts on paper and the paper was passed around to others to draw on, adding their own doodles to the "collective" design. Only a couple of sketches had any combinations of more than one design. Congratulations to those who were able to relinquish their sketch to another's brutal hand. I know it's tough for logical engineer types to "cast about" for inspiration, so congratulations to everyone for participating.

The "logic" of the exercise is to bounce ideas around quickly, building on what another person sees in your idea that you may not. It's also a spin-off on the "two heads are better than one" concept.

I've presented the sketches below and commented on each briefly. Please add your explanation if you are the author and I've missed an important point.

I'll incorporate the ideas, that are new, from this exercise into the CAD model next month. Remember the design criteria...The 4 main design objectives for a "club mascot" should be:

1. Light and easy to transport
2. Big for visual impact
3. Flamboyant, showing off, technological cleverness to be proud of
4. Cheap, cheap,cheap

I took the liberty to combine some of the sketch elements from a couple of different sketches in these first few, sort of in the spirit of the exercise. This one is much like the original design but with arms, head, and camera, added from other sketches. I find the head particulary "modern".

2005-07-25T10:40:00.000-07:00

This one uses parts from several sketches.

2005-07-25T10:39:00.001-07:00

This sketch is specific about components, call-outs are a good thing. The anthropomorphic "face" in un-mistakable.

2005-07-25T10:39:00.000-07:00

The oval head and the square eye band are a cool look. And there's the ubiquitous R2D2 format again.

2005-07-25T10:38:00.002-07:00

This sketch had two contributors. This is a fine example of sharing ideas via the community sketch concept. I have entertained the scissor-lift idea before, but I've never seen the folding / right angle / idea before (in blue). It sort of reminds me of retractable landing gear on a plane. I can see this being used for dolly wheels and such.

2005-07-25T10:38:00.001-07:00

On first glance, this one can seem to be bullet shaped, but the cone is a collection of leader lines pointing to motor locations. It can look like a wheeled cart with humanoid articulated bot (light blue). Or if you include the leaders and turn the face 180deg., the dark blue cart looks like a left foot and the bullet becomes the face. Right brain optical tricks and accidents can become unique designs.

2005-07-25T10:37:00.000-07:00

I was impressed with the idea of the top part unfolding from a cylinder. Puppetry arts is given credit on this one.

2005-07-25T10:35:00.002-07:00

This one seems to have a tank tread platform with actuated links to extend the body. The head is a bit like a cockpit with wind screen. I get a very modern, high tech feel from these proportions.

2005-07-25T10:35:00.001-07:00

The balancing idea definitely fits for criteria #3, "show off". I'ld put holographic projection in the same category. The R2D2 character has so much appeal, it's become the defacto standard when the word "robot" comes up. No matter what gets built, it will always be compared to R2D2.

2005-07-25T10:35:00.000-07:00

This one shows a unique pentagon plan view. The notes suggested a solar panel which I think represents just the kind of redundency, complexity and modularity we've been talking about.

2005-07-25T10:34:00.002-07:00

More articulaton is shown here between two box shaped body parts.

2005-07-25T10:34:00.001-07:00

This one seems to have a tubular framework and folding outrigger wheels. Reminds me of the "shrimp" locomotion bot. I've been looking again at this platform lately because of it's ability to climb stairs with wheels.

2005-07-25T10:34:00.000-07:00

This member clearly wants a battlebot mascot. I believe the intent to do a demonstration robot would preclude destroying it at every presentation, but I could be wrong. Battlebots attract attention. It's possible to fall asleep when "johnny" robot is calibrating his sonars. No so when "etek" is ripping a printer apart. What message do we want to send?

2005-07-25T10:33:00.001-07:00

This one gets the award for ambition. I would love to see a pogo stick design made locally. With the cheap accelerometers and gyros available now, it should be at least marginally more attainable.

2005-07-25T10:33:00.000-07:00

The gripper is clearly defined on this sketch. Autonomous grippers are out there, but beyond my skill level. A gripper that's remote controlled would be visually appealing, and appearently generally expected.

2005-02-27T13:52:00.000-08:00

StarWars robot design is somewhat "Dog-Like"
Keith Rowell Design

February Meeting Update

2005-02-27T11:57:00.000-08:00

The mascot section of the February Club meeting brought some good feedback.
1. Motor Mount

The motor mount design was discussed. The virtues of using an added "plate" to attach the bracket to the gearbox was weighed against keeping the "boss stop" method that the gearbox originally used. The crux of the discussion revolves around wheather any weight is transferred to the gearbox. The general consensus is that the gearbox should "float" and that all the weight should be transferred to the wheel through the axle.

2. Articulated Frame

After discussing the modifications to the "umbrella folding baby stroller" and how to add shrouds and motors to drive articulation on such a frame, it was suggested that we abandon that frame and make one from scratch that suits our needs exactly. This sidesteps the difficulties of making the pseudo appropriate frame fit our critera, while serving as good reference material for a new design.
The in-ordinate ammount of play in the joints of the stroler frame is another source of dissatisfaction and new designs need to take this into account.
Many design mechanisms were suggested:

rack and pinion
drawer slider mechs
scissor lift
ball screw

I'll post some sketches showing some of these ideas applied to our project. I look forward to your feedback.

3. Paint

It appears that the wax (applied too soon after painting) caused the paint to crack. I didn't get many other comments about the silver painted gearboxes. Please provide some input as to aesthetic styles that you would like to explore for the mascot.

4. Reference material

I've included some references here that might provide some inspiration for our mascot's design.

Hoberman was a student of Buckminster Fuller's geodesic dome design principles, and has since created fantastic articulated shapes such as the Hoberman sphere that you may have seen in toy stores. These are amazingly complex expanding structures, definitely the kind of design I would consider to be "showing off" worthy. Here are a couple of his newest mechanical odities.

http://hoberman.com/fold/Switchkick/switchkick.htm

http://hoberman.com/fold/Braintwist/braintwist.htm

http://hoberman.com/fold/assoc/projects.htm#

http://hoberman.com/fold/sightings/clinton.jpg

Some standard off the shelf mechanical shapes:

http://www.hobbyengineering.com/SectionFR.html

http://www.8020.net/

http://www.beijingthc.com/conveyor_chain/carbon_steel_one_piece_chains.htm

http://www.partserver.de/frame.asp?firm=duffnorton&language=english

Mechanical linkages simulations

sphynx is an incredible spherical 4 bar linkage simulator, as is Synthetica. Try them out!

http://synthetica.eng.uci.edu:16080/~mccarthy/Synthetica1.0/Synthetica.htm

http://gram.eng.uci.edu/~mccarthy/SphinxPC/Sphinx.html

http://www.keypress.com/sketchpad/javasketchpad/about.php

http://www.brockeng.com/mechanism/index.htm

http://math2.math.nthu.edu.tw/jcchuan/java-sketchpad/jsp.html

http://www.enchantedlearning.com/physics/machines/Levers.shtml

Fictitious Designs

http://www.colinmackenzie.net/robots/amee/

http://mullenmj.astromech.net/T3M4Droid.htm

Real Designs

http://asl.epfl.ch/research/systems/Shrimp/shrimp.php

GearBox / Motor Mount Design for Folding Frame

2005-02-06T18:58:00.000-08:00

motor mount
Keith Rowell Design

I've worked up some motor mounts based on the discussion in the January meeting. (held in Feb.) These are to mount the gearboxes onto the folding frame.

I was able to modify the folding frame to maintain it's width when closed, as per the meeting comments. It appears that the bottom "x"scissor brace controls closed width, and the vertical "x" scissor brace controls the angle of the vertical frame when fully open. I drilled out the rivetes and moved the connect points and achieved a configuration per saturday's comments. In the current configuration, when the motors are added the full width is 26.7" wide. That's with the frame's outer rails at 12.75". In order to bring the total width down to 24", the folding frame needs to be modified further to have a total width of around 10".

I don't have a camera handy today, I will post those photos when available.

2005-02-06T18:55:00.000-08:00

motor mount front
Keith Rowell Design

The basics of this motor mount design are that the top is a clamp that compresses the frame's down tube. The weight of the bot is carried on the axle that distributes it out to the wheel, passing through the gearbox and coupler. The awkward angle on the motor mount corresponds to a boss on the gearbox, keeping it stationary under torque. It doesn't carry any weight.

2005-02-06T18:54:00.000-08:00

motor mount side
Keith Rowell Design
We of course are looking for volunteers to build this part. There are two of them, identical except for the screw holes which should be mirror copy on the two parts. I have atatched a pdf of the part drawing on the listbot. Contact me if you need a copy...

Casters

2005-01-24T18:57:00.000-08:00

Casters
Keith Rowell Design

I found these cool double wheeled casters in a thrift store for $6. Any of you with children will recognise the stroller. The caster wheels are about 4" and very stable.

2005-01-24T18:55:00.000-08:00

Small space
Keith Rowell Design

I'm fascinated by the way this thing folds up. It's quite complex.

2005-01-24T18:40:00.000-08:00

Articulation Festival
Keith Rowell Design

New Wheels and Adapters

2005-01-10T19:46:00.000-08:00

new wheels and adapters
Keith Rowell Design

I got the new wheel size and adapters from Dale and added them to the CAD files. I also picked up a baby carriage with very cool "double" caster wheels at about 4" dia. We now need to settle on an articulation scheme for motors to automatically do the unfolding and such. If anyone has any ideas, I'ld love to draw them up for discussion.

Dale's Wheel and Adapter Photos

2004-12-27T14:03:00.000-08:00

Dale 08
Keith Rowell Design

2004-12-27T14:02:00.000-08:00

Dale 07
Keith Rowell Design

2004-12-27T14:01:00.002-08:00

Dale 06
Keith Rowell Design

2004-12-27T14:01:00.001-08:00

Dale 05
Keith Rowell Design

2004-12-27T14:01:00.000-08:00

Dale 04
Keith Rowell Design

2004-12-27T14:00:00.001-08:00

Dale 03
Keith Rowell Design

2004-12-27T14:00:00.000-08:00

Dale 02
Keith Rowell Design

Mascot Input at the December Meeting

2004-12-18T14:10:00.000-08:00

We got some good feedback on the Mascot Robot at the december meeting, and there was an impromptu "Mascot design / BS" meeting afterwards at the nearby Dairy Queen.

Comments:

Provide Modularity - This is an effort to make the bot easier to maintain and modify in the future. With different people working on different parts, parallel tracks can be taken, different configurations explored simultaniously, etc. The controller that First uses was discussed because it provides Pendant, MCU and RF control . Does anyone have access to one of these from a retired First Bot? Something to think about is how to make not only the electronics modular, but to standardize on a way to make the mechanicals modular as well. Initially I will just proceed with simple triangle and rectangle modular sections that can be joined at the rotation axis' where the articulations join. (does that make any sense?)

ATmega - Mike Panetta offered two ATmega boards to the project.

Provide space for optical encoder - John Scott has offered to provide "optical mouse" encoders for the bot so space must be provided in the design. I'll put that into the CAD file once results of Dale's modifications come in.

Power transmission - Dale Heatherington took the gearbox and wheel home to try out some different coupling ideas.

Discussion - Discussion spun outward from there into subjects like laser obstacle avoidance ( Home Depot has a new laser range finder $400 ), Ultrasonic local GPS "LPS" schemes (this one is a ripe fruit and not too many others have attempted it), and many other subjects.

A couple of ideas I found particulary intresting. One was to investigate adding a very high level programming interface like Logo ( FlowCode was reccomended by Mike Lynch) so that newbie club members could jump in and get programming quickly on the mascot. Another idea was the posibility of making the mascot "balancing". There are more and more examples of this on the web and in other clubs, and proven code is available. The cost of the required gyroscopes and accelerometers seem to be the main barrier, but this is bound to be a parallel track in the future as those components become available.

EZ Roller Photos

2004-12-15T11:15:00.001-08:00

ez roller 03
Keith Rowell Design

I've uploaded some photos of the ez roller kit from Solutions3. We have two of these and more than enough motor controllers to run them.

2004-12-15T11:15:00.000-08:00

ez roller 02
Keith Rowell Design

2004-12-15T11:14:00.000-08:00

ez roller 01
Keith Rowell Design

Solutions Cubed Inventory

2004-12-07T14:47:00.000-08:00

EZ roller from Solutions3
Keith Rowell Design

EZ roller wheel kit x2
Motor Mind C dual controller x1
Motor Mind B single controler x1
Micro PID Position controller x1
Motor Mind C carrier board x1
Icon interface Module x1
Icon H-Bridge x1

Link to the motor mind spec sheets
http://www.solutions-cubed.com/Solutions%20Cubed/Products2003.cfm

I think the Motor mind C is the only one that controls two motors, you guys might want to check the specs on these parts. The EZ rollers are very nice. The wheels are about 2" dia foam, I wouldn't put more than 6 or 7 lbs on them but they have a very stylish "speed racer" action going on.

New Parts and New Designs

2004-12-06T17:30:00.001-08:00

emergency stop x1
Keith Rowell Design

We've got lots of new parts this week and bold new designs.
Lots of parts are comming this week, forgive me if I miss any;

New Parts
Emergency Stop Button Jay Cross
Fuse Holders x2 Mike Lynch
12vBatt x1 Mike Lynch
1"SqTubing Mike Lynch
from hand truck, includes removable handle
1" round axle stock Mike Lynch
3/8" round axle stock Mike Lynch
retainer caps for same
10"wheels Mike Lynch
4" wheels Mike Lynch

more?
Clint Bridges also gave me the Solutions Cubed box. It's got nice stuff, but I haven't drawn it up yet. I'll report on that next week as time allows. Looks like we are going to wind up with more than enough stuff to build two bots, maybe a Kangaroo and it's Joey?

Still Needed

Castor wheel
Sheet Stock for frame and mounting of circuitboards and such, perforated would be ideal
Sheet plexi Stock for shrouds, mounts, etc.
MCU
Sensors
ideas!

Progress Feels Good
It's been great to see the participation and intrest in this mascot project. I could "re-design" forever, it's in my nature, but I know some people want to get started as soon as possible. I believe Mike has plans to start the hub modification soon and needs a lathe for part of that process. I will have access to one in January. Anyone else anxious?

Next week I will have the "Solutions3" inventory online and maybe some of you guys could look into what parts you would like to incorporate into this bot, and what kind of #2 bot you might want to undertake from those parts.

Also, these CAD files are very convertible. I can export the model in almost any CAD format. Anyone who wants a copy, just email me: rowell@mindspring.com. I would host the cad format files in a central location if it were convenient, and I've looked into it in the past. That collaboration tool hasn't been made as convenient or cheap as the "blog" format so far. I'll bark if that changes.

Just one more thing. Some of these used parts are skuffed up and scratched. If anyone has experience with this new "plastic" spray paint, or has an opinion about colors and "styling", please comment. I can imagine using the dark gray and pale yellow of the AHRC logo. Keeps the theme going. For more color and style ideas, it's very usefull to email a photo showing the finnish you like. I can "pick" these from the photo and use them directly in the rendering program. Seen any cool machinery lately that you'ld like to emulate? Is this going to be industrial grunge like the terminator? shinny like C3PO? or something fancy like the "lost in space second generation"?

2004-12-06T17:30:00.000-08:00

fuse holder x2
Keith Rowell Design

2004-12-06T17:29:00.000-08:00

hand truck mode with handle attached
Keith Rowell Design

From all the input we've gathered, it's obvious that transporting the robot from one place to another is of primary concern. The large 10" wheels would allow it to move over moderate obstacles, even low curbs (not withstanding castor wheel size). Ultimately it has to get stuffed into trunks, and get moved around before and after the presentations, in the most user friendly manner possible. After looking into a folding design that would fit into a tunk, the fold out castor bracket and wheels presented themselves for double duty. Upright it's a castor for the robot, upside down, its a bracket for holding stuff "hand truck" style.

Thanks to Mike's keen insight, the "outrigger handtruck wheels" idea provides easy portability to and from venues.

My original thought was to use the main wheels for both robot locomotion and free wheeling transport. But the gear boxes are impossible to move from the wheel end. I thought about cotter pin locks and electric clutches, but I think bypassing the problem entirely with "extra wheels" is going to work best.

2004-12-06T17:28:00.000-08:00

hand truck mode / castor / bracket open
Keith Rowell Design

Here we see the castor bracket in the open mode. Makes a nice rack for holding other robot presentation stuff like chargers, computers, who knows what. The handle is removable and would mount into an extension of the primary frame, allowing for fairly rough handling vs. pushing the bot/hand truck around holding onto unfolded articulated joints...

2004-12-06T17:27:00.000-08:00

side view / robot mode
Keith Rowell Design

With the handle removed and the bot turned over 180deg, the castor now rests on the ground, the weight of the battery is between the floor contacts, and the handtruck wheels are up in the air. The handle is removed for the demonstration mode.

2004-12-06T17:26:00.000-08:00

castor open
Keith Rowell Design

This image provides a better view of the partially open mode. All views show the new 10" wheels, 1" axle, 12v battery, 1" square tubing frame, and fictitious castor wheel.

2004-12-06T17:25:00.000-08:00

side unfolded
Keith Rowell Design

Adding another articulation, torso like, gets this particular arrangement up to 26". Not very big so far. I've minimized the distances involved in order to get it into a trunk. The frame is stout enough to carry more weight, so we should think about increasing the size as best we can, and still keep it in a managable "folded" dimension.

This begs the question, "how small of a trunk does it have to fit into"? Anyone what to volunteer their trunk dimensions? I'll check mine for a miatta, but I can tell you it's probably already to big for that...

A third articulaton would resemble a head and arms. Any ideas at all that you guys have on these, please post a comment. It keeps things moving along if we get alot of opinions early. Saves on dead ends...

2004-12-06T17:24:00.001-08:00

fully unfolded
Keith Rowell Design

We can get very compact meshing of parts in the closed mode, so we can go ahead and be bold for now in regard to adding stuff like head and arms. Even if we don't implemet these right away, designating space for them now is the ideal path.

I have some ideas about the articulated joints, perhaps motors, or perhaps just locking pins. I prefer the motorized unfolding scenario, but Clint and Mike Pannetta have more experience with that and can definitely give some good feedback on that.

The current scenario shows the electronics in the "torso", batteries and motors in the "base", and sensors ect. in the "head", end effectors in the "arms". Comments please.

2004-12-06T17:24:00.000-08:00

modified hub
Keith Rowell Design

2004-12-06T17:23:00.000-08:00

hub assembly
Keith Rowell Design

The discussion of tire size and torque has been lively, and Dale has kindly volunteered to evaluate the torque vs. tire size for our particular configuration. "Eyeball" estimates seem to bear out the 10" tire size for this gearbox. So I've included some plans for connecting the 10" tires that Mike has.

Some evidence that 10" might work are; that the kiddie cars these gearboxes come from use 10"-13" tires; it's almost impossible to stall by hand; and the ground clearance of the gearbox using 6" tires is minimal. 8" might be ideal if we had any.

The 10" tires Mike has offered are pneumatic with a plastic hub, very nice. Theyre wider than the 2" "dummy" tire I had in the model last week. Mike has a plan to modify the hub so that those two inches are again removed from the width, maintaining our 22" approximate width. This modification ivolves casting a plastic "interlocking" hub that molds to the cavities of the gearbox hub and the tire hub, "lovejoy" style. We don't have lug nuts or wheel locks for this larger shaft, our plan to date is to weld washers on the in-board side, and use cotter pins and washers on the outboard side.

Motor Controllers Donated

2004-11-17T07:40:00.000-08:00

I’ve got a couple wheelchair motor drivers that I bought quite a while ago that I’ll donate. I’ve never used them but I’m pretty sure they are good for 40-50 amps. I’ll dig them out and get you the dimensions.

Ringo

motor controllers
Keith Rowell Design

Thanks for the controllers Ringo. I've shown them blocked in green. The size is 3.75 x 5.5" with a 1" guess at the height. Image shows relative size of motors to boards. Specs are here:
http://members.tripod.com/~divelec/hbridge.html

Axle Shaft Contributed

2004-11-17T07:21:00.000-08:00

I found a shaft that may work well for the Mascot. I've included it in the following images. I'll bring the partial assembly to this month's meeting.

Mascot Parts list to date:

Motors with gearheads___________________________Mike Lynch
Shaft, bearings, wheel locks ______________________Keith Rowell
Motor controller boards __________________________Ringo

Mascot Parts wish list:

wheels
frame material
power
controller
sensors

Images of Shaft, Bearings, and Mounting Hardware

2004-11-17T06:50:00.002-08:00

bearings
Keith Rowell Design
The bearing OD is 0.688"
I have 5 of them and expect to use two per wheel which leaves one spare. This configuration should allow all the weight from the shaft to be carried to the wheels with minimum friction.

2004-11-17T06:50:00.001-08:00

friction locks
Keith Rowell Design

I have 4 friction locks but we may get away with using only 2. They consist of a split sleeve that is threaded and a nut. Tightening the nut locks the location. They fit the shaft perfectly. They're currently attached to a larger OD metal tube and will have to be cut off. I'm looking for volunteers who want to cut these, I think a lathe will be required.

2004-11-17T06:50:00.000-08:00

22 3/8" wide
Keith Rowell Design

I found a nice ground stainless steel shaft that may suit the mascot's needs. It's only 22" wide so it should make it through most doors easily. The OD is 0.311". I have bearings and friction locks to match the shaft. These all came from an old pen plotter so they're quite fine.

2004-11-17T06:49:00.000-08:00

4' high and rising
Keith Rowell Design

I added a virtual box to represent the posible body mass of the bot. This gives a proportional reference as to the scale of all the parts togeather. Shown here the bot is 4' tall and 22" wide and deep.

2004-11-17T06:48:00.000-08:00

new shaft and bearings
Keith Rowell Design

The bearings I have are mounted in these very convenient brackets. There are 5 of these as well. The brackets are aluminum. They're only shown as an alternate. If we mount the wheels on bearings, the shaft doesn't need to turn and won't need bearings at the frame mount.

First part for the AHRC Mascot drawn

2004-11-11T13:32:00.000-08:00

Mike's Motor

This motor is from a child's ride on toy car. Mike can correct me but I think it's 6volt. It looks like the minimum wheel size is going to have to be 6-8". The rib is there to support weight, so the robot frame should go there I guess. We should do some tests on the motors to see what their power characteristics are.

Ringo volunteered a motor driver circuit that is more than powerful enough for the job.

I think the 4 main design objectives for a "club mascot" should be:

1. light and easy to transport
2. big for visual impact
3. flamboyant, showing off, technological cleverness to be proud of
4. cheap, cheap,cheap

Pretty much all development ideas are graded on these criteria, meeting three is pretty much a shoe in but very rare. Hitting two of them is very good indeed. It's always a trade off. While formulating your ideas about how we should develop our "design by committee", think about these objectives.

Everyone's ideas and input are vital, don't hesitate to comment. Your opinions drive the design process. Vote early, Vote often.

I expect the process to take about a year to complete from idea to working bot. The process I envision is an iterative process where I take the comments and sketch them in and present them back. We can go through alot of options this way quickly. Lets give it a try...