Pro's and Con's of Motorized Robot Carts
 

Just wondering what teams have one and what everyone thinks of them. Even after 4 years of FRC in Michigan, I've yet to see any motorized carts. Is this different in other states? We've always had one and have never had any problems with it. Next year we'll be unveiling a new one with even greater maneuverability.

Edit: This is meant to get the word out that they are not bad and if done right can make a team more efficient while not making any volunteers unhappy.

Re: Pro's and Con's of Motorized Robot Carts
 

Biggest Con would be transporting it - ours probably can't come to St. Louis with us :(. But I really like having a motorized cart for the 'bot. We started with one this year via a modified electric wheelchair base and it worked great. It makes it convenient and easy to transport the robot as well as any accessories, parts, batteries, etc. that you need to and from the field, but mostly it just adds to that all-important cool factor :).

But I will say I didn't see any other at Salt Lake this year, and I never remember any at Portland, Seattle, or Sacramento either. A motorized cart is definitely not a necessity, more of a luxury and convenience, but I like 'em. It would have sure made that walk from the pits to the field in Atlanta soooo much nicer!

Re: Pro's and Con's of Motorized Robot Carts
 

I'm neither for, nor against them, but all I have to say is this quote:

"How many motorized carts do you see on the Einstein field?"

Re: Pro's and Con's of Motorized Robot Carts
 

We have one, based off of a motorized wheelchair, and an added scissor lift on the robot platform so that we can work on certain things more easily.
We've never had a safety issue with running people over, in part because we still yell "ROBOT", and because of all the flashing lights we have on it.
Though, of course, we still have a manual cart as a backup, and for carrying other heavy things like parts, batteries, and etc.
But yeah, we haven't seen anyone else that has a motorized cart, I kind of feel bad for the people who have to pull theirs everywhere.

I actually don't have any pictures at the moment, but It's pretty sweet.

Re: Pro's and Con's of Motorized Robot Carts
 

How is this relevant to building motorized carts?

Re: Pro's and Con's of Motorized Robot Carts
 

Cons:
Dangerous
Costly
Heavy
Slow
Annoying to field staff
Annoying to other teams


Pros:
(....crickets....)

Re: Pro's and Con's of Motorized Robot Carts
 

The best teams in FIRST make it to Einstein. They don't have motorized carts.

It means you really don't need one. With the weight and size of a motorized cart, you can have a beefed up normal cart. I've seen carts carry tons of batteries, a toolbox, a screen with scouting data on it, and even one that weighs so little it's like pushing a 150 pound box with a tap of the foot.

Re: Pro's and Con's of Motorized Robot Carts
 

This shouldn't turn someone away because all the teams that make it to Einstein don't use them. This is kind of like the Mecanum wheels and Einstein. There will eventually be a Mecanum robot on Einstein, maybe in the future there will be a motorized cart on Einstein.

Re: Pro's and Con's of Motorized Robot Carts
 

Touché. There may be, there may be not, Only time will tell, and only teams that make a motorized cart will find out. Just passing on the information given to me.

Re: Pro's and Con's of Motorized Robot Carts
 

Let me add one more con from a Robot Inspector's point of view:

In the pit, with the cart in the pit (where else can you park it?) and the bot on the ground to check bumpers, there is NO space left to do anything.

Re: Pro's and Con's of Motorized Robot Carts
 

Just because they are the best, doesn't mean other teams have to do what they do. Sure, I want to get to Einstein, but I don't have to transport my robot like the Einstein teams do.

Building a motorized robot cart might not take you to Einstein, but could be a great summer project to use up some of those spare parts. Our 2010 robot didn't perform too well and was small enough to fit through the tunnel (and a standard size door). We are contemplating taking that working drivetrain and chassis, adding in an old IFI control system and a simple lift, and modifying it into something useful.

Re: Pro's and Con's of Motorized Robot Carts
 

The way I interpreted it was that the teams on Einstein know the pros and cons of the motorized cart and stay away from it because of them. I'd love to build one, but to actually use it would probably get some people angry (I like to please the robot inspectors), and would be a pain to use in the pit.

That being said, I still have the CAD for one. Won't ever build it, but it's still cool (maybe a motorized vehicle for promotional stuff, but not for the competition, like the OP was talking about)

Re: Pro's and Con's of Motorized Robot Carts
 

From a practicality standpoint, a motorized cart is useless. It's a bit like a hybrid automobile in that regard.

However, there are positives to making one if the students do it and learn from it. It's another chance for them to learn to wire, gear, power, and program a robot correctly.

Do NOT put flashing lights, music, noise makers, or other beepers on it. Underglow is cool and looks acceptable.

If, however, you've got extra bumpers, putting a couple of those on your cart would be appreciated when you over-zealous cart drive runs over someone else (as happened to me twice this weekend).

Re: Pro's and Con's of Motorized Robot Carts
 

My thing is, why build a motorized cart when you can build a ROBOT that you can you can use to strictly demo?

Re: Pro's and Con's of Motorized Robot Carts
 

We found an elegant solution to this potential problem, we use our motorized cart as our work table, the entire platform (which is a flat table top with about 1" tall blocks on the corners to prevent the robot from falling off) that we can raise anywhere from about 1 foot to about 3 feet off of the floor so we can work on every part of the bot without straining our bodies with the constant bending and kneeling that we would otherwise have to do without it. As for the motorized carts on Einstein reasoning, if you utilize even basic engineering principles and develope it during the off season it does nothing but help the students get a better idea of what to expect going into build season. Its like everything else in the world, there is a right and wrong way to approach it.

Re: Pro's and Con's of Motorized Robot Carts
 

It sure did for us! We put a camera on the front of ours after a match and went back to the pits.

Re: Pro's and Con's of Motorized Robot Carts
 

I think you misinterpreted the meaning behind a lot of the posts here. Absolutely nobody is saying that working with your team is a bad thing. Nobody is saying building a motorized cart is a bad thing. They are offering alternatives and lending their opinions on the matter.

The title of this thread is "Pro's and Con's of Motorized Robot Carts" yet you seem to be very negative toward those who have offered cons. I just don't think it's fair to judge the members here because they have negative opinions about motorized carts. "If you are so determined to ruin the point of this thread and crush the hopes and dreams of young engineers..." I feel like there were at least a few better ways you could have put that statement. It's pretty offensive because everyone here is working toward the goal of inspiring students to go in to STEM fields.

Re: Pro's and Con's of Motorized Robot Carts
 

There are few pros to motorizing a cart. A lightweight, skeletal frame cart with casters can do the job perfectly.

Re: Pro's and Con's of Motorized Robot Carts
 

What Joe said. Nobody is criticizing you. You asked for our opinions, and we provided. The word "opinion" does not just mean whatever you want to hear. Some people don't like motorized carts. Big deal. You make them every year, and that's great. Nobody is chastisizing you for it.

Honestly, I'm kinda offended by your post. I know for sure 100% that you didn't mean it to sound rude (trust me, I'm the king of that sometimes), but next time read what you're saying.

I find this rule helpful:

This is a great thread, no matter the result. People are posting their opinions, which is the focus of a forum, and people are learning things, be it the pros and cons of a motorized cart, or an important life lesson.

Best regards,
Andrew

Re: Pro's and Con's of Motorized Robot Carts
 

I love S.W.A.T's cart its so cool

Re: Pro's and Con's of Motorized Robot Carts
 

Our team built a motorized cart in 2010 and brought it to the OKC regional. The safety judges there asked us to not use it for future competitions because of the safety hazards it creates in confined walkways. I believe team 1742 (who also had a motorized cart for a time) was asked to do the same at one point.

S.W.A.T. did you experience any comments from the safety staff about your cart at OKC this year?

I very much enjoyed having a motorized cart because it makes the transportation process much easier and has a certain "cool factor" about it.

You might contact someone on your local regionals safety staff and ask what they think about it.

If they don't like it, I would suggest not pursuing the idea. Otherwise, Do it!

Re: Pro's and Con's of Motorized Robot Carts
 

I would never use a motorized cart. Our carts don't even have handles, the robot is locked in place on them and then we use the robot superstructure to carefully push the entire thing along.

Re: Pro's and Con's of Motorized Robot Carts
 

I thought when you asked for pros and cons that you actually wanted both.

Re: Pro's and Con's of Motorized Robot Carts
 

There are other ways to electrify a cart as part of a robot project other than motorizing it. Make reactive LED underglow with an arduino that corresponds to your bumper color is one way.

Re: Pro's and Con's of Motorized Robot Carts
 

We built a motorized cart several years ago -- it had a lift that could raise and lower our robot to proper lifting/working heights, too -- and then never ended up using it. It was too big, too clunky, and just one more thing to worry about breaking...

For the past several years we've used a good old fashioned drop-down dolly, painted purple of course and with Bausch + Lomb stickers and our team number on it. It's lightweight, compact, portable, and easy to get out of the way when we need it out of the way...

340 has a new cart this year, too. It's got a lift-off work table so they can work under their robot in the pits, that locks in solidly so they can cart the bot around... It's not motorized, but it's pretty slick.

Re: Pro's and Con's of Motorized Robot Carts
 

I think the trend of those carts stemmed from 2003 championship where the walk from the pit to the field was atrocious, and required going up and down many flights. As a tiny girl on the drive team, pushing those robots gets tiresome. It was similar, but probably not as bad in Atlanta.

When I was in high school, 177's cart wasn't motorized, but we had a mechanical scissor lift that could lift and lower the robot for easy work in the pits. This made the cart really heavy.

Honestly I'm kind of "meh" on the idea of motorized carts. I see students just driving them around to play with them, and that's where it gets dangerous

Re: Pro's and Con's of Motorized Robot Carts
 

Question: When people talk about a "Motorized Robot Cart" in this context, is "Remote Control" (wireless or tethered) implied? I can see how that gets more dangerous, and more tempting for people to play around. What if it were more like a self-propelled lawn mower: when you pull a lever while holding the handle, you get motor assist, but if you let go, it stops/coasts.

I'm not an inspector, but I think they would likely not prohibit a simple motor-assist design. I'm also not an event volunteer, but I think they would not be annoyed by this (they probably wouldn't notice, since it is less likely that anyone would be goofing off with such a cart).

Our team had a motorized cart several years ago (before I was with the team). They said it was too big, and caused trouble, so they removed the motors and smallerized the cart. [Everybody please start using "smallerize"; I want to make it a real word. 8-) ] That cart has served us well for several years now. Although, now there's talk of a new-and-improved cart, with scissor lift and such. I think good things will come of that. It will make a useful summer project, with goals->requirements->design, hands on work, imagery, and much potential team benefit.

Re: Pro's and Con's of Motorized Robot Carts
 

We used our cart every match this year at both Kansas City and OKC without a complaint from any of the volunteers or the safety judges.

EDIT: We made the cart in 2008 and have taken it to every event since, this includes Champs twice (2008 & 2009), Kansas City (2009-2012), STL Regional (2009 & 2010), 10,000 Lakes (2011), OKC (2012), Cowtown Throw Down (Off-season event 2008-2011), plus many other promo and demo events.

Re: Pro's and Con's of Motorized Robot Carts
 

Technically we have a motorized cart. Sometimes we use the battery compartment to store stuff, batteries go in the middle under the robot since they are big and don't fit through the gap in the sides, but tools would fall out of that area of the cart, the battery compartment, on the other hand, has enclosed sides...

Re: Pro's and Con's of Motorized Robot Carts
 

This is our cart we have had no problems with running over people because it is very easy to control. It has a 5gallon air tank, underglow, a sound system for all the other days of the year when we're not at the competition, and an ooga horn when yelling robot is overated and it rolls along at the flick of a joystick. The whole thing was student welded student assembled student wired simply put no mentors had anything to do with the building and assembly of it. The stickers and paint were designed and chosen by the students.

Re: Pro's and Con's of Motorized Robot Carts
 

We built a barebones aluminum square tubing cart that can be disassembled and put against a wall of our crate. How do teams that build massive carts with speakers, lights, etc., and especially motorized systems, transport them to competition, especially championship?

Re: Pro's and Con's of Motorized Robot Carts
 

What are you doing with all that air?

Re: Pro's and Con's of Motorized Robot Carts
 

My thoughts exactly. There doesn't seem to be a pneumatic lift or anything on it.

Re: Pro's and Con's of Motorized Robot Carts
 

Maybe it's one heck of an ooga horn! :ahh:

Re: Pro's and Con's of Motorized Robot Carts
 

Hahaha.

Re: Pro's and Con's of Motorized Robot Carts
 

I believe what it comes down to is quite simply: Haters gonna hate

A motorized cart is only as dangerous as its operators and design. I think the FIRST community contains some extremely hipocritical ideas when it comes to *safety*. For the most part, the ones complaining that these things are unsafe are really just sore because they didn't have the resources, foresight or skill to build one themselves. This is apparent from the overwhelming praise we have recieved for our efforts and the handful of critisisms.

CONS:
-potential for breakdown
-diversion of team resources
-difficult to transport
-another item requiring maintenance

PROS:
-Increased safety (brakes, controllability, reduction of strain injuries)
-An excellent team building and learning exercise
-Convenience at competitions/mobile pit
-Marketing tool (helps improve team image)

The first motorized cart I helped build was with team 854. It was a ride-on unit built by frankensteining the hardware from an old wheelchair to a custom chassis with automotive steering which also allowed for a 0 turing radius. It was maneuverable, had a lighting system on it to make it conspicuous and a motorcycle horn which had been wrapped in tape to make it quieter yet effective at notifying people you were behind them. It was a great project for the younger members to learn skills which later helped us build some great robots. It was also designed to be an integral part of the pit setup providing a work surface and a place to keep things like spare parts, tools and batteries.

The second motorized car I was involved with was for 2013. It was also made by frankensteining motorized wheelchair components to a custom frame. It had three onboad marine batteries (two for 24V propulsion, one for on-board power). It had 1500W of 120VAC power and 12VDC outputs as well. It too was equipped with lighting and a sound-deadened horn. This version was much more functional than the 854 model using only wheelchair steering but included much more storage space as well as a telescoping floodlight for field-side robot repairs during eliminations. It too was an integral part of the pit and served as both a tool cabinet and primary work surface.

The third motorized cart I helped out with was also for 2013 and was more of just a fun toy for around the shop than to be used actively at competitions. This unit was built from a small 2ft cube steel cabinet with a door. It had a tricycle setup where the operator would sit on the top of the cabinet with their feet over the front. There were two wheels under the "cube" and a fork/handlebar assembly at the front. It was powered by a single CIM motor and planetary gearbox powering the front wheel. The battery was a tired old MK robot battery also mounted to the front fork. Control was provided by a variable speed ESC from an old cordless drill which was mounted to one of the handlebars like a throttle lever. The ESC had a forward and reverse function like the drill as well as a brake function when released. This cart was fitted with a sound-deadened horn and lights. It had team sponsors and name displayed like the others before it as well as a few "WARNING BATTERIES ON BOARD" graphics because inside was a 5 bay TecMate Accumate 5 charger, stock of battery acid neutralizer and ventilation fan. This cart would sit in the corner of the pit area and took care of all battery charging duties. It would charge 5 batteries at once and would hold up to ten. During eliminations it could be driven out to the field and plugged in to the aforementioned robot cart to provide field-side charging.

I am a huge proponent for motorized carts because of the additional safety they afford. I can't tell you how many times I have seen teams pushing their robots at a running pace. A motorized cart is speed limited. I also remember at the houston championship, teams struggling to push their robots up steep concourses and frantically trying to slow them as they barreled their way down. As long as these things are built and operated with respect like you use any other cart they are just as safe if not far safer.

The only reason team 3756 didn't have a motorized cart this year was because the wheelchair chassis they purchased did not come with the control interface (joystick) and we were unable to find one in time to build their cart.

Issues: Now here is where I get frustrated. In boston, 2013 was told that they had to push their cart rather than drive it with no reason or explanation given. They put the motors in freewheel mode and there was no problem. However, every time, like any other cart, when they came to a cable protector, they had to gather speed to get their robot over it. Motorized, it would simply crawl right over. It was far more difficult to control manually than while powered. This decision by staff to make them push it created several hazards which they continually refused to acknowledge as they were brought to their attention.

At the GTR regional however, the safety inspectors praised the team for their hard work and attention to detail in building it and they were encouraged to use it as intended the entire competition. I myself remember seeing about 7 different occasions where they recieved safety credits from other teams specifically for their cart. By the end of the competition I believe they had 38 safety tokens.

I like the wording in the administrative manual stating that carts must be safe but I challenge those who march about declaring anything that is different, unique or imaginative to be *unsafe*. Those people are indeed limiting the creativity of our teams and "squashing the dreams of young engineers".

If FIRST bans the use of electric carts then I will insist that they also ban the use of segways, golf carts, police patrol scooters and yes, electric wheelchairs at their events as well.

Re: Pro's and Con's of Motorized Robot Carts
 

Below is our first cart we made and it served us well for many years. When it's fully completed it'll be posted here. Ironically it's very similar to this video... ;)

http://www.youtube.com/watch?v=N-ETKfkhta8

Re: Pro's and Con's of Motorized Robot Carts
 

We drive there and tow our regular trailer.

Re: Pro's and Con's of Motorized Robot Carts
 

All you need now is a sponsor from a lawn mower company. :P

Re: Pro's and Con's of Motorized Robot Carts
 

We use the air to charge our robot pneumatics and use air drills and wrenches, there are never enough plugs in the pit plus when it comes to final matches it comes in handy. Also the cart folds in half for easy transport under buses and in trailers, during the season we use it as a forklift to transport heavy loads for golf tournaments shop tools ect.

Re: Pro's and Con's of Motorized Robot Carts
 

harbor freight had a sale going on so we found a use :)

Re: Pro's and Con's of Motorized Robot Carts
 

That's cool I love air tools.

Just remember you can't use that air to charge your robot for matches.