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-   -   Drivetrain, what did you use? (http://www.chiefdelphi.com/forums/showthread.php?t=20105)

maclaren 13-04-2003 01:29

Drivetrain, what did you use?
 
I just wanted to hear what people used for their drive trains including:
Team #?
# of years of participation?
# and type of motors?
# and type of drive wheels?
# and type of non-drive wheels?
Transfer system(chains, belts, etc.)?
Transmission (not including supplied ones)?
Steering?
Sensors?
Success?
Problems?
Next year?

My response:
team 997
2nd year
2 drill motors
2 solid rubber 9"dia. 60 durometer 3" wide
2 wheel chair wheels
direct drive via shafts and gears
the supplied right angle gear box
automotive rear-wheels steering
no sensors
we busted the supplied gear box once and our steering sucked
never use automotive steering ever.
next year simple box chasis tank steering as many motors as possible and a transmission.

sanddrag 13-04-2003 03:08

Team 696
3rd year team
2 drills and 2 chiaphuas
4 Skyway 9x2 Beadlok turned down to 8.5 di
0 non-drive wheels (casters are not allowed near our robots)
#35 Chain with carbon steel sprockets riding on 5/8 keyway shaft
3.5:1 reduction between Chiss and Drills; 4.8 reduction between drills and wheels
Skid Steering
No sensors
Much success, 9fps and loads of torque.
Problems - Misalignment, shafts wandering out.
Next year - Provided we have the same equipment, we will either do the same thing with some minor refinements or have a totally new 2 speed drive. Depends on game and engineer support.

Pat Fairbank 13-04-2003 10:25

Team 296
5 years
2 drill, 2 CIM
4 solid rubber 6" wheels
no non-drive wheels
belts between the motors, chains to the wheels
supplied transmission
skid steering
no sensors
success - ~10 fps and lots of power
problems with pulleys coming un-setscrewed and with drill transmission
next year - depending on the game, maybe something a bit more complicated like crab

Gui Cavalcanti 13-04-2003 11:05

Team 422
4 years
2 CIMs (previously 2 CIMs and 2 drills)
2 6 inch wide 6 inch diameter machined aluminum wheels with hard neoprene covering
2 HDPE machined skids - 3 inch diameter touching the floor
Direct drive using a gearbox for the CIM to gear it down to the high speed of the drill; we then mated both on a giant 80-tooth gear on a 5/8" shaft to the wheels
Two-wheel drive (tank-style steering)
Two optical sensor encoder wheels to count the revolutions per minute
The giant wheels were great on the ramp, and the CIMs gave us some good pushing power.
Our robot was not symmetrical and the weight was balanced more over the skids, so we had some trouble getting weight issues settled. We eventually ended up placing over 20 pounds of dead steel weight over our drive train.

Next year we're going to deal with the symmetry issues, but this two-wheel drive was very successful, small, and modular, so I think we'll keep it.

Jeff Waegelin 13-04-2003 11:59

Team 201
6 years
2 CIMs
4 1.5 inch wide, 6 inch diameter custom machined aluminum wheels
No non- drive wheels
Chain drive from a 2-speed transmission
Skid steering
No sensors
Success- really fast, good amount of power, no reliability issues
Problems- can't turn in high gear
Next year- not my problem :p I'm a senior, though I hear my team is trying for swerve drive next year... we'll see...

Yan Wang 13-04-2003 12:59

-Team 639 - Code Red Robotics
-This was 3rd year.
-2x Chiapuas
-2x Modified Skyway from Kit for back
2x Omniwheel with 65 grade urethane
-No non-drive wheels
-Chains
-No Transmission, high torque 6.5fp
-Tank Drive, logarithmic control
-Optical Sensor for bin tracking
-Great success
watch www.orbitreview.com/~temp/639movies/639_d.wmv
-None (each regional we had nothing to fix/tune after practice day because we actually spent the time to do tings right this year. We just left the robot outside in Chesapeake for cooling :)
-.... very secret

rbayer 13-04-2003 13:57

Team 6
9? maybe 10?
2 drills, 2 CIMs
4" brecoflex pulleys
0
Brecoflex belts (the green)
None
Sort of
None
A LOT of speed. We were one of the fastest at UCF.
We couldn't really turn until Sat. after we broke the belts in a little
Depends on the game

ebmonon36 13-04-2003 15:16

Team #1018
First Year
2 drill motors
2 pneumatic tires from a hand cart
2 UHMW skids
#35 Chains
Sprokets from MSC with about a 2:1 ratio
Tank Drive
No Sensors
Nice mix of torque and speed
In Chicago we had problems with the chains walking of and in one case had a connector link fall off
I think we are going to try to make a gearbox this summer

Kevin A 13-04-2003 16:10

Team 481
4th year
2 Drill, 2CIM
4 Rubber skyway wheels 9" dia
0 non- drive
Gears for cim, provided gearbox for drills
0 sensors
Succesful...kinda - drill trans kept breaking, cim gear box sheared teeth and broke shaft, but no problems at nationals
Next year...shifter

jonathan lall 13-04-2003 21:59

Re: Drivetrain, what did you use?
 
Quote:

Originally posted by maclaren
Team #?
# of years of participation?
# and type of motors?
# and type of drive wheels?
# and type of non-drive wheels?
Transfer system(chains, belts, etc.)?
Transmission (not including supplied ones)?
Steering?
Sensors?
Success?
Problems?
Next year?

-Team 188, Woburn Robotics.
-6 years of participation.
-2x CIM, 2x Drill, and 2x Fisher-Price.
-Wooden wheels with tread, four-wheel drive.
-No non-drive wheels.
-Chains run to front and back wheels for four-wheel drive.
-One-speed only.
-Tank-style steering.
-Sensors on the wheels to count revolutions and/or pointing down to detects the line or the HDPE.
-A good balance between speed and power; in a fairly high gear (speed of about 9ft/s), we could still push well because of six-motor drive, with a low-friction simplistic gearbox
-It draws way too much power, and by the end of a heated match, our robot can barely move. So many drive motors sometimes cause us to trip breakers. We made the mistake of using small chain rated for about 1000 pounds (25), instead of something stronger, we went through 13 of them because they stretched and snapped all the time. Our treads kept delaminating from the pushing matches we got into, so a better means of traction needs to be developed.
-Next year, we're going more complex, possibly with a new gearbox design conceived on the plane back from Houston that can do speed and power without most of the drawbacks we faced, and that's all I'll say. We're looking at tank treads also. Anything else is just speculation, stuff I don't know, or stuff I don't want everybody to know. :)

Keith Chester 13-04-2003 22:08

Team 25
7 years participation (2 under my belt)
2 drills, 2 Chippys
3 wheels a side.
0 nondrive wheels
Direct drive (all gears baby!)
1 speed
Tank steering
No Sensors
Success- 13.6 fps, 3.2-3.6 autonomous time.

Problems- Drills! ARGH! Drove us crazy at first. Our programmer and pit crew came through in a miracle to fix that one.

Next year? Who knows.

AlbertW 13-04-2003 22:17

Re: Drivetrain, what did you use?
 
Quote:

Originally posted by maclaren
I just wanted to hear what people used for their drive trains including:
Team #?
# of years of participation?
# and type of motors?
# and type of drive wheels?
# and type of non-drive wheels?
Transfer system(chains, belts, etc.)?
Transmission (not including supplied ones)?
Steering?
Sensors?
Success?
Problems?
Next year?

  • 1072 (go hrt!!! :D)
  • rookie team
  • 2x Drills
  • 4x skyway wheels with traction material epoxied on (back wheels were effective on the carpet/ramp, front wheels were effective on the HDPE)
  • no non-drive wheels
  • chain drive for both front and back, motors mounted vertically using helical gear set
  • bosch transmission and supplied helical gear sets
  • tank-steering. the bot would skid on the wheels not suited for the material it was on (if it was on the ramp/carpet, the front would skid, if it was on the hdpe, the back would skid)
  • 3 banner sensors mounted on bottom for line-following, though we didn't end up following the line
  • the drivetrain worked pretty well.
  • The traction material fell off the wheels alot, and we had some wiring issues with the motors. our transmission broke once, but it was easy to fix. our servo-powered gearshifters never made it onto the bot. there wasn't enough torque to move the little switch on the bosch transmission.
  • don't know about next year. We stayed away from more advanced systems like omniwheels and crab drives cause we were a rookie team, but we might just be more ambitious next year ;)

Daniel Brim 13-04-2003 22:18

Team 294
Seven Years
2 Drill motors
2 9 inch skyways
2 non drive wheels (locked casters)
First gearboxes
None (we stay in low gear)
2 wheel steering
None for drive
SoCal regional finalists (we lost one match)
We didn't lock the casters at first, causing problems going up the ramp and popping breakers at Phoenix
Next year we are planning something like 111s drive, that was our plan A (ended up with D)

Andrew Rudolph 14-04-2003 16:54

Team 212
5 of years of participation
2 drills
8 inch pneumatich wheelchair wheels
No non drive wheels
Chains
Gearing off of the FIRST gearbox
Tank style, we had a very short wheelbase so we turned really well and had the 4 wheels on the ground for the grip
No sensors
Never had any problems with the drive train, we made this thing like a car with hubs and all it was 1000% sucessful
Next year? i dont know depends on the game duh!

Josh Hambright 14-04-2003 18:36

Team 461 - Westside Boiler Invasion
4 Years
2 Drill Motors
4 Skyway wheels. Modified and lathed down an inch or so with supergrip rivited into a channel in the wheel for better traction.
None
Chain. 1.5:1 Gear ratio
None
Tank
Rotary Encoders on the front wheels
Speedy, Robust, Easier to fix and replace stuff then our previous attempts at a drive, we just decided to go simple and not mess with complicated stuff.
We didn't have alot of torque.
We are going to dive into the wonderful world of transmissions:)

SiliconKnight 20-04-2003 03:22

Team 824

Second year team

We attempted to manufacture our own gearbox. Shifter was taken off to make manufacturing schedule. All parts were student made - reliablity was good with 1 motor, but under 2 motor loads, reliabilty was a problem. (it exploded on the field at our very last match at PNW).

* Tank drive robot
* 2 "drive pods" modular drive system, on and off the robot very quickly.
* Optical encoders on driven wheel.
* Custom made aluminum wheels - attach just like a car's wheel with a wheel flange. Started out as a track system but the tracks kept falling off.
* Each pod contain 1 chip, 1 drill motor. There is a matching stage where the free spin RPMs are matched, then the output of that goes through the drill reduction box. Custom outtake shaft then drives the wheels.

Problems we encountered:

* Failure to account for the side load on the helical gear
* Bad construction quality on some of the press fits.
* Failure to calculate in the backlash - I used theoratical spacing for all the gears - that was a BAD mistake.
* Lack of tools and trained personnel (no one could weld, didn't have a knurling tool for press fits, no CNC trained operator to cut the bearing pockets, etc.

-=- Terence

DougHogg 21-04-2003 02:36

Drivetrain, what did you use? (post #1)

I just wanted to hear what people used for their drive trains including:

Team 980
2nd year
Motors? 2 CIMs
Drive wheels? 8 wheels, 4 at a time.
# and type of non-drive wheels? 4 wheels on the ground at a time, and the other 4 spinning in the air
Transfer system(chains, belts, etc.)? Gear boxes and chains
Transmission (not including supplied ones)? 2 Custom Gear boxes. 8 full time spinning wheels. We used pneumatics to push a lever which rotated 4 large wheels down for high gear and 4 small ones for low gear.
Steering? Tank
Sensors? Gyro for autonomous movement, potentiometers for controlling the position of 3 arms.
Success? We have a 13 foot telescoping arm which was exceptional at taking down the stack from our starting position.
Problems? We had 3 arms, one 13 footer, and 2 for pushing and stacking bins. That left us short on weight for our drive system. In making everything light enough, the drive system was too flexible and we lost chains if pushed sideways. Later we found ways to reinforce it.
Problem 2: In 3 competitions, we tipped a total of 3 times (average of 1 per competition) when rammed by other robots.
Problem 3: After watching other robots in Houston, our acceleration could have been better. 4 motors would have helped. Also in high gear, our wheel base was short which made us rocky given our high center of gravity.
Next year? I would like 4 motors in the drive train, hopefully with shifting.

Jared Russell 22-04-2003 22:03

-Team 341
-My second year, team's fourth
-2 drill motors
-4 drive wheels
-0 non-drive wheels
-Chain drive
-We welded ourselves into low gear ;)
-Tank steer
-Sensors: gyro for autonomous position control, optical sensors to pick up top of the ramp.
-Success: +100% autonomous mode; +GREAT wheels (high traction); good tradeoff of speed and torque
-Problems: -Drill motor mounts; -Wish we were a little faster
-Next year: Expect 4 dedicated drive motors, almost certainly

Matt D 22-04-2003 23:59

254
 
Team 254 (Cheesy Poofs)
# of years of participation? 5 years
# and type of motors? 2 drills this year
# and type of drive wheels? 4 6"X1" custom wheels with blue tread material (forgot where from)
# and type of non-drive wheels? caster dropped down with a pneumatic cylinder only for autonomous steering
Transfer system(chains, belts, etc.)? serpintine chain
Transmission (not including supplied ones)? none other than supplied drill transmissions, which we shifted with servos
Steering? during autonomous we dropped down an angled caster
Sensors? none
Success? yes! no breakdowns at Nats, we drove well, getting to the boxes in 3.8 s in auton, but by shifting could still outpush most robots
Problems?, a few problems with the transmissions at SVR
Next year? gears not chain (we broke a master link in a match at SVR and chain is a pain)

Vu2000 23-04-2003 02:42

Team 812
2 years
2 Drill Motors
4- 9 x 2 skyways
No No No non-drive wheels
Chains that control the sides of the robot
Supplied Transmission with a few adjustments nothing to gears

Steering: 2 globe with Universal Joints to articulate wheels
3 types of steering-
Mode A: Where the rear and front turn in opposite directions like Chevy's truck commercial
Mode B: Where the rear and front steer same direction
Mode C: Tank

No sensors
Success: 6th at AZ 9th qualifying

Problems: Not that good because the wheels could only turn 30 deg, we had 10 deg of play to the left, design problem with the key always shearing under the globes DO NOT USE THE HOUSING FOR THE TRANSMISSION GIVEN, We had every possible problem happen to us at least 3 times at SoCal.

DONT USE TOO MANY CUSTOM PARTS, THEY"RE A REAL HASSLE AT COMPETITION ESPECIALLY IF THEY BReAK BETWEEN MATCHES

The team was planning on using chiaphua's with high reduction, the mechanics team and I wanna do and plan this summer a dual output, shifting on the fly with at least 4 gear ratios drive system.

Or maybe Servo?

FotoPlasma 23-04-2003 03:39

Team number: 258

Years in FIRST: 5 years.

Drivetrain motors: 2 Atwood (CIM), 2 Drill, 2 Globe.

Driven wheels: 4 custom machined aluminum 6.5" wheels with MSC timing belt tread. (Picture of wheels and tread).

No non-driven wheels.

Transfer method: <Neo>Gears. Lots of gears.</Neo>

Transmissions: Four custom fabricated gearboxes, one for each of four drive motors (drills and Atwoods). Pictures. Pictures. and more pictures.

Steering: As Vu2000 stated, three distinct control schemes: 1) translational (all swerve modules are pointed in the same direction), 2) complementary (front and back sets of modules turn to complementary angles, in order to reduce the turning radius, as commonly seen on the GMC Denali (truck commercial with the object driving in a figure-eight so much that it makes you sick)), and 3) tank (both sets of modules are pointed straight forwards / backwards, and the robot is controlled as though there were no rotational component, whatsoever).

Sensors: Two potentiometers, without hardstops, which recycle at 360degrees. It took a good few hours digging around in local electronics surplus stores to find these babies, but I'll tell you, they were well worth it.

Success: I'd say that we were very successful. We seeded 5th at Silicon Valley, and had a great time. Quite the learning experience that FIRST intends us to have, if I do say so, myself.

Problems: Driver training was very difficult. Becoming oriented to the controls was definetly not the easiest thing to do, and we didn't have too much spare time to just drive around. Autonomous mode was rather interesting, seeing as though we only had it for the last few matches of the competition.

Next year: Well, there's lots of talk about a much more advanced system, but beyond that, I'm not at liberty to say, at this point in time.

Don't be afraid to IM or email me with questions or comments, or whatever.

Andy A. 23-04-2003 08:57

Team 95

7 years (I think)

Drive motors: 2 drills, 2 CIM; one for each wheel

4, 8 inch skyway wheels, heavily modified.

2 window motors and 2 Globe motors for steering. Each wheel is independently driven and steered (full crab)

Drive was through worm gears. Steering was originally done with cable, but later changed to timing belt. Theoretically, we had full Ackermen steering and crabbing.

Sensors: no optics, we did use 4 pots to sense each wheel modules orientation.

Problems: Lots of them.

First, worm gears are very, very inefficient. Due to binding problems, this was even worse and we just lost to much power. Our speed was targeted to 8fps, it ended up being around 4.

Second, we had lots of issues regarding the pots. simply put, they drifted out of calibration after hard hits and just were never accurate enough.

Third, there was never enough time to get the custom circuit running. Because of this, all the calculations for steering was done on the RC. Because of the limitations of the RC, the math was very round about and filled every bit of memory we had. It's slow and inaccurate.

Fourth, the original design called for the wheel modules to be steered by motors connected via a capstan like cable setup. It actually worked and saved a good deal of weight. However, we found that in competition we would get rammed against the wall and the repeated blows would rip the cable out. So we replaced them with timing belts in Houston. But, because belts only come in 10 tooth increments sizing was a huge hassle.

Fifth, It was a bear to drive, and the complete lack of practice killed us. Ultimately, we got the mechanical problems pretty much figured out but our driver had never gotten the chance to play with it.

So ya, next time around we'll know what we are doing. It was a learning experience for sure. It's kinda tough to go from balls, which is something we know backwards and forwards, to making a complex drive train (past years have always been 2 drills end of story). It was easily the most complex thing we've ever made, and next time around it'll be fine.

-Andy A.

Powers 23-04-2003 10:08

Team # : 710
3rd year participating
2 chips, 1 globe
drive wheels : 4 goped wheels
non-drive wheels: 2 pneumatic wheelchair wheels
4 wheel drive (back wheels)
2 wheel steering (front wheels)
chains connecting wheels in back
chips to drive
globe to steer

front steering wheel fell off in one match, but we re-inserted b4 the next match and it worked fine.

next year's plan is crab drive.

Al Skierkiewicz 23-04-2003 10:24

Team #111

# of years of participation? 8

# and type of motors? 2 Drills, 2 FP, 2 Globe(steering)

# and type of drive wheels? 4-custom 6" dia. aluminum with conveyor belting, glued and riveted for tread. (Same as last year.)

# and type of non-drive wheels? 0

Transfer system(chains, belts, etc.)? DNA

Transmission (not including supplied ones)? 4 custom, optimized for motor type, one at each drive module. Modules independently replaceable, 4 screw mounting plus electrical connector.

Steering? 4 wheel crab. Two available (pneumatically controlled) feet to lift two wheels and allow conventional two wheel steering.

Sensors? optical for rotation sense, gyro for turning sense, pots for steering and wing control.

Success? All worked, rotation/gyro/software combo (interfaced at custom circuit board.)gives ability to program auto mode to anywhere on playing field within +/- 6 inches. Up to 11 programs can be stored on board. Select one at time of robot placement on field depending on alliance partner, opposition and field placement.

Problems? Slower than some, less push than some, best on carpet or ramp.

Next year? We will optimize for whatever the game requires and parts available.

purplehaze357 23-04-2003 14:17

Team # 357

# of years of participation? 4 and counting

# and type of motors? 2 drills, 2 chips

# and type of drive wheels? 6 Inch pneumatic tires

# and type of non-drive wheels? 0 non-drivers

Transmission (not including supplied ones)? n/a

Steering? its a 4 wheel translational drive, essentially if you know what a crab steer looks like then you should be set.

Sensors? Opticals that read white tape and a sprocket inside the wheel assemblies to be used for distance in our auton period.

Success? We won this years regional Chairmans Award at the Chesapeake Regional, and we won the Delphi's Driving Tomorrows Technology award at the Chesapeake Regional. At the Philadelphia Alliance Regional we won the animation Award. We also made a stack of 3 totes in Philadelphia grabbing the bins off the top of the ramp and driving them down.

Problems? We discovered early on that our robot was comparable to bringing a ballerina to a mosh pit. Our drive train was fragile creating problems when battlebot style pushing would occur.

Next year? To build a robot and continue the Royal Assault on the FIRST competition.

JVN 23-04-2003 15:22

Gen1 - 229
 
Team 229 - Clarkson University "Division by Zero"
This is our teams 5th year.

Motors-
2x Drill, 2x Chiaphua

Wheels-
4x 6" skyway wheels, turned down and coated with "Kingman
Tread" (1.2 mu)

No dead wheels...

Chain-
Serpentine - 3/8" Chain

Tranny-
2x All-Custom, 2-speed, 2-motor, shift on the fly (pin style).

Steering-
Standard Tank Steering...

Sensors-
Custom Current Sensors measure Drive-Motor current draw. Protects us from popping breakers. 2x IR Wheels allow us to calculate wheel speed and robot position (vector addition).

Successes-
We felt the system was fairly successful. This was our team's first attempt at a custom gearbox, and we certainly aimed high. (A combiner, AND a shifter in our first try... what were we thinking!?!?!) With a lot of love, and some profanity we managed to get it running smoothly, and shifting like a champ.

Problems- Mostly mechanical failures... we had to work the bugs out of our system...
We were torsion fracturing 3/8" dia. steel output shafts. We ended up going to a 1/2" dia. shaft for nationals, and the problem went away.
We also had some problems with our idler system throwing chain. We managed to work the bugs out eventually.
The large loads involved destroyed some of the plastic skyway wheel-hubs we were using... we had to replace a few of those...

Next Year...Well...
We've got a shifting - swerve drive about half designed. (Swerve-ZER0)
We've got a 6-wheel omni-drive (like 343 - 2002) designed up.
We're playing with improving out current drivetrain. (Generation2)
Time will tell...
Regardless of the game, you'll probably see our Gen2.5 gearboxes on the robot in one form or another...


You might even see us playing around with some new technology at off-season comps...

Gadget470 23-04-2003 15:34

Team #470
# of years of participation? 4th Year
# and type of motors? 2 CIM's
# and type of drive wheels? 4
# and type of non-drive wheels? 0
Transfer system(chains, belts, etc.)? Independant chains to each wheel
Transmission (not including supplied ones)? 12:1 Gearbox, no shift
Steering? Tank-style
Sensors? None
Success? We were a powerful pusher, but a little slow.
Problems? At nationals we had a chain fall off twice, but still drove and shoved people around with 3 powered wheels.
Next year? Designs are in talks, nothing decided yet, but it will be neat if I get my way.

Solace 23-04-2003 15:54

Team 571
3rd year team
2x drills, 2x chippy
2x 8 inch pneumatic wheels
All chain drive
All chain transmission (no shifting)
Tank steering
no sensors

success: Very Fast (12ft/sec) but slightly underpowered, reasonably successful (always in the finals at regionals and championships, ranked 3rd at UTC)

problems: we initially had problems with the chains popping off, but we fixed those by pinning the adjusting mechanism in place.
next year - we're ditching the chain, gonna try to do a complete gear drive train. Plans for a 4 motor, 2 speed on the fly tranny are in the works.

Joe3 23-04-2003 16:03

Team #365

# of years of participation? 4

# and type of motors? 2 Bosch's, 2 CIM's

# and type of drive wheels? 4 custom 6" aluminum wheels with neoprene wrapped around, attached by tie-wraps.

# and type of non-drive wheels? 0

Transfer system(chains, belts, etc.)? Chain, independent to each wheel

Transmission (not including supplied ones)? 2 custom, we geared the CIM's down to the same as the bosch's in the low setting.

Steering? Skid steering

Sensors? Two gyro's for autonomous, one for the turn to go up the ramp, one to stop the robot once we got off the ramp.

Success? Everything worked as planned. It was a fairly simple system, so, nothing major broke. Good combination of speed and torque.

Problems? The only problem we ran into was a chain falling off (twice).

Next year? We're looking into hovercraft, and a form of a mag-lev vehicle. No, but we're exploring several more advanced options.

Austin 23-04-2003 17:14

Team #45

# of years of participation/since establishment of team? 12

# and type of motors? 2 Drill, 2 CIM

# and type of drive wheels? one belt/drive pully per side, tank style

# and type of non-drive wheels? ....about 6/7 idlers per side ;)

Transfer system(chains, belts, etc.)? direct drive, gears

Transmission (not including supplied ones)? 2 custom shift-on-the-fly

Steering? Skid steering

Sensors? 4 light sensors for autonomous to tell us when we reached the HDPE

Success? won wm under the wing of 292...had hindering reliability problems the rest of the season

Problems? Gears breaking, shift-shaft broke, controller reseting, victors frying, auto-mode...etc...etc...lol not fun! :ahh:

Next year? you'll just have to wait and see...try to guess! ;)

Jnadke 23-04-2003 18:09

Re: Drivetrain, what did you use?
 
Seeing as nobody else posted this...


I just wanted to hear what people used for their drive trains including:
-Team #? 269
-# of years of participation? 4
-# and type of motors? 2 CIM
-# and type of drive wheels? 2 Drive wheels (8" I believe)
-# and type of non-drive wheels? 2 Non-drive steering wheels (6")
-Transfer system(chains, belts, etc.)? Direct Drive gears
-Transmission (not including supplied ones)? No transmission. We did have a differential for steering (allows one wheel to move faster than the other), but was removed due to problems.
-Steering? We had Ackerman steering which allowed us to get to the ramp in 5 seconds consistently.
-Sensors? None
-Success? Seed 6th in Curie.
-Problems? Differential had problems with parts breaking, so we used a different drive system. It still worked, but didn't have the same high-traction drive wheels.
-Next year? Dunno.


Other than team 16, I don't think any other teams utilized a true Ackerman steering system. Correct me if I am wrong. I am not referring to casters. Ackerman steering is where the front wheels do the turning fully (usually unpowered, but they are powered by a front differential in AWD cars). The rear wheels are both set to go either full forward or full reverse.

If you want a really good demonstration, check out Curie Match 65 or Curie Match 115. Credit to Soap108.com. If we had higher traction wheels we could cut our time down because the robot actually goes through some acceleration-limiting code when the robot starts up (we were spinning wheels).

Adam Y. 23-04-2003 18:13

Quote:

We had Ackerman steering which allowed us to get to the ramp in 5 seconds consistently.
Edited for not reading the post. Edited again for not reading the post for the second time. So what differntial did you use?? It sounds like you used an underrated part.

Adam Y. 23-04-2003 18:24

Quote:

The problem wasn't in the differential itself (that worked flawlessly), but in transferring power to the differential. I noticed they were using 1/4" shafts and set screws...
Ahhh thanks by the way do you know where they got it??? The only differentials I have seen look like they would not work in a robot.

Quote:

The rear wheels had less traction than the steering (front) wheels (which we were originally going to use), so there were no problems in turning even though both rear weels were operating at the same speed. Unfortunately we were pushed a little easier than we would have hoped.
Ahhhh I thought that may work. Thanks. Were you ever worried that if one of your wheels were up in the air that the robot would not move since all of the power would be going to that wheel?

Jnadke 23-04-2003 18:33

Quote:

Originally posted by wysiswyg
Stupid question but did you have a differntial on you drive shaft or did you just mount a chain to it directly???? I was wondering this.
We did originally have a differential on it, but we had many problems at the Midwest Regional, so we ended up dumping it and going with a drive system developed by one of our sister teams (with the help of our engineers). The other option was to replace the gears on the differential with a belt system. The problem wasn't in the differential itself (that worked flawlessly), but in transferring power to the differential. I noticed they were using 1/4" shafts and set screws...

The rear (newer) wheels had less traction than the steering (front) wheels (which we were originally going to use with the diff), so there were no problems in turning even though both rear weels were operating at the same speed. Unfortunately we were pushed a little easier than we would have hoped.


I'm just a college student/alumni that was helping to mentor them. I wasn't at nationals but I was at the Midwest Regional.

Quote:

Ahhh thanks by the way do you know where they got it??? The only differentials I have seen look like they would not work in a robot.
The differential was actually a free-floating differential (also called an open differential - there are many different designs). It consisted of a nylon housing to which a large gear was attached (the drive gear). The housing was basically 4 bevel gears of the same size, to which 2 shafts were attached (the 2 that are perpendicular to the drive gear).

You can see a good picture here:
Differential
Steering

Unfortunately, I don't have any information as to whether they made it or bought it. If you look at the design, it wouldn't be that hard to make with a mill and drill press. All you need is a high-strength plastic like Delrin or Polyethylene. Take a square of it and mill out a perfect square inside. Drill 4 symmetrical holes on each side and mount the bevel gears (preferrably steel). They should all be mounted solid (can't move), 2 of which should be attached to the wheel shafts. Then attach a drive gear (or sprocket) to the housing (not to the wheel shaft). A bit more complex, but that's the basic idea.

At MR they replaced the nylon gears with steel one's. The differential worked nicely for a match, but then it broke again when a nut came out, so the decision was made to switch to the alternate, alternate drive system permanently (Plan A was nylon gears and hollow driveshaft, Plan B was steel gears and solid steel driveshaft, Plan C was belts, and Plan D was the drive system you see now). If you can get past all the kinks (using 3/8" steel shafts, keyways, and getting rid of those nuts), it'd be perfect.


There are many different kinds of differentials. There are differentials with bevel gears (open differentials). There are differentials with worm gears (Torsen differentials). There are even differentials with planetary gears (TrueTrac differentials). Open differentials are the simplest and most efficient, but if one wheel loses traction you're screwed. Torsen are the most complex and least efficient, but they have the ability of transferring torque to the wheel with traction. The TrueTracs are somewhere in the middle, but they require a little bit of initial friction to transfer the power to the other wheel (the slippage can't be instantaneous).

Quote:

Were you ever worried that if one of your wheels were up in the air that the robot would not move since all of the power would be going to that wheel?
Yeah, that was a concern, but if you look at the steering picture, you can see that our it pivots on the vertical. It's semi-articulated so that both rear and front wheels are on the ground no matter what position the robot is in relation to the ramp. The only way we would have that problem is if a robot got under us.

abeD 23-04-2003 18:47

We almost used a differential on our bot, till we thought that it wouldnt have helped us that much, and it ended up that just putting a 4 wheel tank in the back with two wheel steering the front(not casters but steered by a globe motor) worked great, ended up in 3.8 s autonomous and easy and fun drivability during matches.

here's a pic, u can see the 4 wheel tank in the back with the two wheel steering in the front,(no only the battery in the back is plugged in the other two are for weights to simulate the arm weight).
http://www.chiefdelphi.com/forums/pi...&quiet=verbose

tatsak42 23-04-2003 19:28

Re: Drivetrain, what did you use?
 
Team #? 159
# of years of participation? 6? i dunno
# and type of motors? 4 drive motors, 2 drill and 2 Fischer Price (until we had to redo our drive @ regionals to 2 drill tank drive w/ casters >_<
# and type of drive wheels? 2 drive, 6 inch dia.
# and type of non-drive wheels? 2 casters >_<
Transfer system(chains, belts, etc.)? gears. custom gearboxes... ah will do better next year.
Success? Well, with just 2 motors, we still had quite a bit of power...
Problems? FP motors destroyed, aka, no translational
Next year? Ah well, work on that again... so that it works ;D

Ricky Q. 26-04-2003 14:43

Quote:

Originally posted by Adam Y.
Ahhh thanks by the way do you know where they got it??? The only differentials I have seen look like they would not work in a robot.


The differential that was orignally in our bot was designed and manufactured by our team. It was designed with the help of one of our new engineers from Harley-Davidson, he had much experience with the design of them, but not the assembly, so as Jnadke said, we had some issues with it and dumped it. It would have worked perfect if we would have had more time, we expect to work more on it in the summer. We went with the alternate drive and employed a software differential at Nationals and had little or no problems with the steering, it worked like a charm and made us pretty manuverable as opposed to tank drive robots, if your going to IRI head on over to our pits and check it out. We proabably will put a steering wheel on the controls to make it more car like, its a ton of fun to drive.

Rob Colatutto 26-04-2003 17:27

Re: Drivetrain, what did you use?
 
Team 263
- 5 years participation
- 2 CIM (atwood, chippy, chalupa, etc)
- 2 custom 10 inch dia. 7 inch wide aluminum wheels, wrapped in neoprene, very good traction
- 0 non drive wheels, 2 hdpe (teflon in the past) skids in front. currently dubbed the sled bot by SBPLI judges
- 4:1 4:1 gear reduction, then 7:5 chain reduction
- no shifting...yet
- 2 wheel rear steering, no drag in the front of the robot
- 2 sensors to tell them robot in autonomous what side of the field its on to determine what turn to make
- 100% success with the drive train, no failures and ability to push most other robots
- problems... wheels were too wide and too big (although smaller dia than our previous wheels). combiner would have helped, had one last year but deemed it unneeded only to turn around and decide it does help to have one
- next year, swerve (crab like) drive (we hope) currently working on a prototype now, if successful it will become the model for next years and the robot cart. 2 drill in front with custom gearboxes, 2 chippy in the back with custom gearboxes. experimenting with window, globe, fp, and van door to turn the wheels, not sure what works the best yet

Gobiner 26-04-2003 22:59

Team 753
2 years of participation
2 drills, 2 CIM motors
2 BrecoFlex belts, the red ones that tear.
Custom gearboxes linking CIMs with drill transmissions.
Tank style steering.
No sensors.
Very successful at Seattle, never met a robot we couldn't push. Geared to go about 8 ft/s with no load.
Had major trouble at Houston with the drill transmissions slipping into neutral, then with the clutch housing coming off the planetary gear housing.
Next year? Whatever next year's students want to do.:cool:

Tom Bottiglieri 15-02-2004 17:50

Re: Drivetrain, what did you use?
 
*Totally new design this year*
Team 195
8 Years
2 Drill
2 Treads Spanning over 32 inches of ground each
NO other wheels
Chains
Super Duper Gear Down Tranny using chains are gear reductions
2 joystick tank drive
no sensors
we have lots of sucesss with our down low tank designs
We have had problems with our past trannys (set screws vibrating loose)
only time can tell

OneAngryDaisy 15-02-2004 19:51

Re: Drivetrain, what did you use?
 
whoa, someone totally brought back a dead thread. almost a year old too- i'd reccomend starting a NEW thread for 2004 instead of confusing half of the people here... (got me at first)

pras870 15-02-2004 20:49

Re: Drivetrain, what did you use?
 
- Team 870
- 3rd Year
- 2 Drill Motors set in high speed
- 6 9" Pneumatic Skyway wheels
- 2 6" Skyway solid wheels
- #35 chain with 60 tooth sprockets on wheels, (4) 14 tooth idlers, and 11 tooth sprockets on extended drill motor shafts
- Standard Drill Transmission
- Tank Drive
- None as of now
- Speedy, plenty of pushing power. Only problem is that it tends to bounce when doing a ZTR turn.
- Next Year: Would like to try a gear box incorporating the CIM and Drill Motors

Tom Bottiglieri 15-02-2004 21:09

Re: Drivetrain, what did you use?
 
love doin that ;)


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