I've been looking around for a good motor that could let my robot go backwards and forwards at slower speeds, and I found·a very cheap one. The only problem is I'm not sure how good of quality it is and whether I should get it or not, so please check it out and tell me.
Also, if you think there is something better, please advise me.
Although I am still waiting for an answer on my last Q, I thought I would give you all some insight as to what I did today.
As you may notice in the steering picture I got for you, the motor hangs down farther than the bottom of the frame. This is a problem because if the robot goes over any rocks or thick foliage, the motor is very likely to get hit. This would immediately take out my steering. So, to fix it, I used a piece of metal to lift·the motor·up on my frame. It is a little hard to explain in words how I did it, so I will soon get you a picture of this.
After lifting the motor, I tacked on the pivoting system to the 3/4"·rod. If you look in the above picture, you will see thicker ends to the bar traveling in the center before it reaches the 1/2" thick bolts. These thicker rods (1 1/2") have been hollowed out to slide on the inner 3/4" rod. This is what I tacked together.
Now that this has been done, I have two more main parts to finish with the steering. The first thing is to finish the connecting·the system·to the motor. Since it was originally made to fit on the motor when it was lower, I now have to increase·it's height. My current plan is to make the flat metal piece (seen in the picture) that is connecting the ends of the system together into an upside down "T" before having a hinge connect a rod from it·to the end of the motor shaft. After this is done, I'll check all the steering to ensure it is running correctly before finishing welding the end metal rods to the 3/4" rod in the center.
I hope I explained it well enough for you, and whatever I didn't I hope will be answered for you in·my·next·picture.
Forget about the·motor, I can't seem to be able to get any more dang info on it other than what the website link I gave you says. I found two sources for the motor, and both gave links to a dead end. So, looking around, I found another motor that should be able to do the job. It's just a bit pricey, though.
...of course, I could always save a little money by going to the junkyard. I think I will go there first and check out the motors before I bail out 130 bucks for the above motor.
I got the pics of the steering again. If you look at the old pic and the new one, you can see what has now been done differently.
I haven't been able to give that bar going over the "T" shape I was talking about, but all the parts have been made for it. I will do the necessary welding for that·section tomorrow.
Take a look at http://banebots.com/p/M4-R0062-12
You can find them elsewhere as wel (e.g. http://andymark.biz)l.
I have used these motors both for my own projects and as part of FIRST robotics team. I haven't had a problem with them.
My only worry is if it will be capable of moving over a hundred pounds of steel at a decent speed. Since the motor doesn't mention the horse power, I'm guessing it is too low for the power to be shown on that scale. If it is less than 1/4 hp, I'm not sure it can do much of anything unless multiple units are used, which is unfeasible.
If any of you are math geniuses, you can help me solve this. I want enough HP to go about 8 mph and the weight layout is something like this:
30 pounds for the engine
I have no clue how heavy the frame is, but I know it is more than the engine. Maybe 40 pounds?
~6 pounds for the battery
~4 pounds for the alternator
As for the wheels, I have no clue, but I'm guessing about 20 pounds for the four of them.
Also, weight will be added as I put on all the extra parts necessary on the frame.
I truly don't expect anyone to do the work of solving this for me, but I would really appreciate it if you did. But if not, it at least helps demonstrate approximately how much power I will need for the task.
We and a lot of other teams use 2 CIMs (1 per side to move a 150lb robot) and we limit the current to 40A per motor @12V so max of 400W or ~.5hp per motor (allowing for losses).
It will depend on the gearbox. Banebot and andymark have gearboxes that take 1 or 2 CIMs so you can double the power if you need.
I think you said you had 14" wheels so for the CIMs rpm ~5600 you need a gearing of ~25:1 for 8mph thats going to increase the torque a lot. For the 150lb robot we used a 12.75:1 gearbox followed by a 1.5:1 chain/sprocket to give about 19:1 and 6" wheels for max speed of about 5mph
Hmm, you're quite intelligent on this stuff. I've thought about starting a FIRST team in my own school, but it will be difficult, so I'm not sure how soon I wish to try. But for now, I'll just stick to the BOEs Parallax kindly donated to my school. But if I should get a FIRST group started, things should get exciting with half the year for the BOEs, and half for FIRST.
As for the motor, it seems it will be $95 for everything I need. It seems a little pricey for a project that uses 2 freebie motors. Think I could get any of the parts for a little cheaper?
Also, I just thought I'd mention I will check out the junkyard tomorrow anyway and see if I can get just as good of a motor there for cheaper, such as maybe $5 (I heard that was their usual price tag). I will keep the other motor in mind, however, as I search. It's still a good possibility.
If you want to start of FIRST team but FRC is a bit complex/pricy look at FTC or VEX, they are a lot cheaper and easier to handle.
Another place to look for motors is allelectronics.com, I noticed that they had some electric scooter motors in recently.
All the stronger motors at allelectronics.com are 24v, which worries me that they might not run as well at 12v, but really I have no clue.
@Mill Creek Metals, the junkyard place I was referring to before, I found a .33HP 12v motor that might be a possibility. I believe it's rpm is ~1700. Their charged price was a little high, at $25 (I guess they charge a little more for larger motors). It is very nice, almost looking like new, but if the FIRST motor is truly .5HP @ $30, it might be a better option. One thing I like better about it, however, is it has a slower speed making gearing a little bit easier. Instead of being forced to buy a $65 gear box, I can use the pulley system I took off of my engine which was connected to a tiller, essentially making it free. But, just to be before purchasing it, what do you guys think?
One more thing I thought I'd mention is that I really appreciate hearing all of your suggestions, even though I don't always use them.
I may not use Timmoore's motor idea, but it definitely brought out problems I would have to face, including lowering the rpm to a usable rate, as well as helping me look at the cost of an option when everything necessary is included, such as gearboxes.
The only reason I thought I'd mention this is because I feel some of you aren't posting your ideas because you are worried I will reject it. But, in all reality, it only helps and I really appreciate your responses.
I should probably run my engine a little less, my ears are ringing.
I worked on improving my engine rpm code, but I'm not sure if it is entirely accurate. If it is, then 4,800 rpm is about the max for what my engine can do right now until I get it upgraded. The min is about 1800.
If it is all working correctly, I will try and get my prop to control it using the servo. Maybe I'll even post a vid on youtube.
"BigBlank"? If that's a joke, it's not funny. If it's serious, then I pity you. If it's a typo, then, really, please correct it (and excuse my utter flabbergastery).
Post Edited By Moderator (Dave Andreae (Parallax)) : 5/19/2009 3:33:45 AM GMT
I'm sorry, but age has nothing to do with it -- it's bigoted and offensive. Name your projects whatever you like, but when you volunteer such a name during a public discourse, I will argue that you have a social obligation to contain yourself. That's all I have to say, really.
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Pi Guy said...
Although it isn't of any real importance, I just thought I would mention that I'm thinking of calling the robot "LittleOne" or some variance of the name. FHR worked fine for me a while ago when I was going a little more toward the serious side, but I'm now thinking I need something better to call it.
BTW- Don't expect the name FHR to go away. My plan is to say, "It's name is FHR, also dubbed LittleOne."
Hey guys,
In no way do we condone this type of language and we will take steps to end it now regarding this thread. You have to remember that this is a family oriented forum for all ages. If this is something that you cannot grasp I suggest that you quickly find another forum to join, we will not tolerate this type of behavior.
Dave
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Dave Andreae
Parallax Tech Support
Post Edited (Dave Andreae (Parallax)) : 5/19/2009 1:14:58 PM GMT
It was not my intent, I didn't even realize it was that bad. I guess my insolence has finally caught up with me, damned me. I am sorry, so truly very sorry, that I have caused an uproar on these forums, and more so, that I have offended you. As for now, I will be taking a break from these forums until I feel ready again. I will miss all of you, you guys have truly been a great help to me. But I guess we all make mistakes at some point in our lives, and the only thing left to do is move on. I am sorry.
Thank you for the apology.· We all make mistakes and I'm not looking to ban you from the forums for one mistake.· My goal is to make you aware of our policies and hope that in the future you'll learn from this incident.· I have read over several of your posts and I truly believe that you are a positive influence in these forums.·
I must say I don't like posting on these forums anymore, but I might as well suck it up and do so for those who care.
I have, of course, been working on my robot in this long while between posts, however the focus of what I have done has changed slightly as I no longer have the equipment of the school welding shop, but never the less it has been quite beneficial towards the completion of my robot.
I have been test driving the vehicle manualy since I do not have the required hardware to use electronics, and it has worked, while also showing some problems. Because of the engines pulling force, the bolts are able to easily slip throwing everything out of alignment. When this occurs (such as when accelerating too fast or climbing steep inclines) it will throw the chain off the sprocket.
Although no idea·is set in stone, one possibility I was provided with is to use a jack screw to hold the engine in place. I have heard a couple other ideas; however this one seems to be the best possibility.
I appreciate those who have supported my project so far and I will keep you up to date on future progress.
After spending over fifty bucks on tools today I have been able to mount my engine better so the chain won't slip. Now it is working so well I'm actually having problems with my clutch sending out sparks and smoking, but I'm sure I can solve that problem later.
I should soon be able to make my robot do some simple tasks soon; however I will be somewhat limited as to what I can do until I can get my hands on a welder. I have a few parts I assembled before summer, but they now just have to be welded on to connect my motor to the rest of the steering. My hope is to be able to do it this weekend.
I'm dying for VIDEO of this monster one day! I've noticed u get miffed at the lack of feedback on your project every now & then, and i think thats not from lack of interest but from lack of knowing how to help you. Remember, this is more of an electronics centered forum than a mechanical centric forum. This seems closer to a go-cart than a robot...but i dare u to prove us wrong! Knock us dead.
p.s. ..and remember think of creative names for bots..
Good luck
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ "THE ONLY TRUE WISDOM IS IN KNOWING YOU KNOW NOTHING." - SOCRATES
Pi Guy said...
After spending over fifty bucks on tools today I have been able to mount my engine better so the chain won't slip.
Ah, tools. I personally think it's much better to go out for nice tools (and lots of them) then to feel frustrated at not being able to do something or having it take too long. It's nice to have a well stocked workshop (or tool bin) to choose from.
lol dave, maybe i shldnt dare try for a "creative name" anymore. ive spent too much time with the wrong sorts of people. bt whn u tlk about frustration, u hit that right on the mark! @ slrm, yes, but its too bad they cost so much. the way its going right now ill just have to keep it a gokart cuz i cant afford the electronics. lol
"I'm dying for VIDEO of this monster" After posting on my phone I tried recording it running, but it was too hard while working the gas and air at the same time. Once I can get it semi-autonomous I should be able to get it for you all. ·
Not exactly autonomous, but I got you guys a vid of the drivetrain working: http://www.youtube.com/watch?v=xDg97tvPZHY
I currently have many·things to do, though, like taking a hammer and straightening the wheels and preventing the left wheel from falling off, lol. But what I really hope to get done is to complete the connection of bar to motor so I can steer. Then with a little·programming I'll have a robot!
Comments
Also, if you think there is something better, please advise me.
http://www.retailerdeals.com/sass/product_details-453256727-3829-1_4_HP_12V_DC_Motor_5400_rmp_for_Hobby_Brand_New_On_sales!.html
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PG
As you may notice in the steering picture I got for you, the motor hangs down farther than the bottom of the frame. This is a problem because if the robot goes over any rocks or thick foliage, the motor is very likely to get hit. This would immediately take out my steering. So, to fix it, I used a piece of metal to lift·the motor·up on my frame. It is a little hard to explain in words how I did it, so I will soon get you a picture of this.
After lifting the motor, I tacked on the pivoting system to the 3/4"·rod. If you look in the above picture, you will see thicker ends to the bar traveling in the center before it reaches the 1/2" thick bolts. These thicker rods (1 1/2") have been hollowed out to slide on the inner 3/4" rod. This is what I tacked together.
Now that this has been done, I have two more main parts to finish with the steering. The first thing is to finish the connecting·the system·to the motor. Since it was originally made to fit on the motor when it was lower, I now have to increase·it's height. My current plan is to make the flat metal piece (seen in the picture) that is connecting the ends of the system together into an upside down "T" before having a hinge connect a rod from it·to the end of the motor shaft. After this is done, I'll check all the steering to ensure it is running correctly before finishing welding the end metal rods to the 3/4" rod in the center.
I hope I explained it well enough for you, and whatever I didn't I hope will be answered for you in·my·next·picture.
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PG
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_391581_391581
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PG
I got the pics of the steering again. If you look at the old pic and the new one, you can see what has now been done differently.
I haven't been able to give that bar going over the "T" shape I was talking about, but all the parts have been made for it. I will do the necessary welding for that·section tomorrow.
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PG
You can find them elsewhere as wel (e.g. http://andymark.biz)l.
I have used these motors both for my own projects and as part of FIRST robotics team. I haven't had a problem with them.
If any of you are math geniuses, you can help me solve this. I want enough HP to go about 8 mph and the weight layout is something like this:
30 pounds for the engine
I have no clue how heavy the frame is, but I know it is more than the engine. Maybe 40 pounds?
~6 pounds for the battery
~4 pounds for the alternator
As for the wheels, I have no clue, but I'm guessing about 20 pounds for the four of them.
Also, weight will be added as I put on all the extra parts necessary on the frame.
I truly don't expect anyone to do the work of solving this for me, but I would really appreciate it if you did. But if not, it at least helps demonstrate approximately how much power I will need for the task.
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PG
It will depend on the gearbox. Banebot and andymark have gearboxes that take 1 or 2 CIMs so you can double the power if you need.
I think you said you had 14" wheels so for the CIMs rpm ~5600 you need a gearing of ~25:1 for 8mph thats going to increase the torque a lot. For the 150lb robot we used a 12.75:1 gearbox followed by a 1.5:1 chain/sprocket to give about 19:1 and 6" wheels for max speed of about 5mph
As for the motor, it seems it will be $95 for everything I need. It seems a little pricey for a project that uses 2 freebie motors. Think I could get any of the parts for a little cheaper?
Also, I just thought I'd mention I will check out the junkyard tomorrow anyway and see if I can get just as good of a motor there for cheaper, such as maybe $5 (I heard that was their usual price tag). I will keep the other motor in mind, however, as I search. It's still a good possibility.
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PG
Another place to look for motors is allelectronics.com, I noticed that they had some electric scooter motors in recently.
@Mill Creek Metals, the junkyard place I was referring to before, I found a .33HP 12v motor that might be a possibility. I believe it's rpm is ~1700. Their charged price was a little high, at $25 (I guess they charge a little more for larger motors). It is very nice, almost looking like new, but if the FIRST motor is truly .5HP @ $30, it might be a better option. One thing I like better about it, however, is it has a slower speed making gearing a little bit easier. Instead of being forced to buy a $65 gear box, I can use the pulley system I took off of my engine which was connected to a tiller, essentially making it free. But, just to be before purchasing it, what do you guys think?
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PG
I may not use Timmoore's motor idea, but it definitely brought out problems I would have to face, including lowering the rpm to a usable rate, as well as helping me look at the cost of an option when everything necessary is included, such as gearboxes.
The only reason I thought I'd mention this is because I feel some of you aren't posting your ideas because you are worried I will reject it. But, in all reality, it only helps and I really appreciate your responses.
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PG
I worked on improving my engine rpm code, but I'm not sure if it is entirely accurate. If it is, then 4,800 rpm is about the max for what my engine can do right now until I get it upgraded. The min is about 1800.
If it is all working correctly, I will try and get my prop to control it using the servo. Maybe I'll even post a vid on youtube.
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PG
Post Edited (Pi Guy) : 5/20/2009 4:46:29 AM GMT
Post Edited By Moderator (Dave Andreae (Parallax)) : 5/19/2009 3:33:45 AM GMT
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PG
In what way? I'm your age, and I consider it offensive...
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When the going gets weird, the weird turn pro. -- HST
1uffakind.com/robots/povBitMapBuilder.php
1uffakind.com/robots/resistorLadder.php
Hey guys,
In no way do we condone this type of language and we will take steps to end it now regarding this thread. You have to remember that this is a family oriented forum for all ages. If this is something that you cannot grasp I suggest that you quickly find another forum to join, we will not tolerate this type of behavior.
Dave
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Dave Andreae
Parallax Tech Support
Post Edited (Dave Andreae (Parallax)) : 5/19/2009 1:14:58 PM GMT
Derrick Huestis
Thank you for the apology.· We all make mistakes and I'm not looking to ban you from the forums for one mistake.· My goal is to make you aware of our policies and hope that in the future you'll learn from this incident.· I have read over several of your posts and I truly believe that you are a positive influence in these forums.·
Regards,
Dave
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Dave Andreae
Parallax Tech Support·
I have, of course, been working on my robot in this long while between posts, however the focus of what I have done has changed slightly as I no longer have the equipment of the school welding shop, but never the less it has been quite beneficial towards the completion of my robot.
I have been test driving the vehicle manualy since I do not have the required hardware to use electronics, and it has worked, while also showing some problems. Because of the engines pulling force, the bolts are able to easily slip throwing everything out of alignment. When this occurs (such as when accelerating too fast or climbing steep inclines) it will throw the chain off the sprocket.
Although no idea·is set in stone, one possibility I was provided with is to use a jack screw to hold the engine in place. I have heard a couple other ideas; however this one seems to be the best possibility.
I appreciate those who have supported my project so far and I will keep you up to date on future progress.
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PG
I should soon be able to make my robot do some simple tasks soon; however I will be somewhat limited as to what I can do until I can get my hands on a welder. I have a few parts I assembled before summer, but they now just have to be welded on to connect my motor to the rest of the steering. My hope is to be able to do it this weekend.
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PG
p.s. ..and remember think of creative names for bots..
Good luck
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"THE ONLY TRUE WISDOM IS IN KNOWING YOU KNOW NOTHING." - SOCRATES
Ah, tools. I personally think it's much better to go out for nice tools (and lots of them) then to feel frustrated at not being able to do something or having it take too long. It's nice to have a well stocked workshop (or tool bin) to choose from.
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PG
After posting on my phone I tried recording it running, but it was too hard while working the gas and air at the same time. Once I can get it semi-autonomous I should be able to get it for you all.
·
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PG
http://www.youtube.com/watch?v=xDg97tvPZHY
I currently have many·things to do, though, like taking a hammer and straightening the wheels and preventing the left wheel from falling off, lol. But what I really hope to get done is to complete the connection of bar to motor so I can steer. Then with a little·programming I'll have a robot!
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PG
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PG