| Author |
Message |
Marcello Marabese (Marab)
Member
Username: Marab
Post Number: 21
Registered: 8-2006
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| Posted on Sunday, April 22, 2007 - 4:48 pm: |
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Hi, was wondering if you could recommend a set of motors which could be used to drive ~25kg. And also an appropriate power supply.
Cheers
Marcello |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 462
Registered: 10-2004
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| Posted on Monday, April 23, 2007 - 8:22 pm: |
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Marcello,
At what speed and when you say "power supply" do you mean a mains powered power supply?
Regards
Paul |
Marcello Marabese (Marab)
Member
Username: Marab
Post Number: 22
Registered: 8-2006
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| Posted on Tuesday, April 24, 2007 - 1:08 pm: |
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Hi Paul,
Well, it doesnt need to be fast, a slow walking pace, as long as it can take the weight. Well by power supply i meant: Can you recommend the best way to supply power to the motors, they will need to be running for atleast 40 mins maybe longer.
Thanks.
Marcello. |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 465
Registered: 10-2004
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| Posted on Tuesday, April 24, 2007 - 2:12 pm: |
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Marcello,
4 mph is nice and slow so plenty of gearing and / or small wheels. A few more questions - how will it steer, will you be using rubber treaded wheels and does it have to do 'any work' other than propel itself along?
Do you need to be able to vary the motor speed and do you need remote control?
Regards
Paul |
Marcello Marabese (Marab)
Member
Username: Marab
Post Number: 23
Registered: 8-2006
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| Posted on Tuesday, April 24, 2007 - 2:23 pm: |
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Hi
Paul,
Well the robot will be used outside on grass, and will need to be able to grip well. So the wheels cannot be two small. If rubber wheels would give it good grip, then they would be fine.
The only work it will have to do is carry the weight of ~25 kg around a surface which will be un-even, there will be parts of the environment where it will have to go up hill.
A remote control is not needed, varying the speed would be an advantage, but not essential.
In terms of steering, I was thinking that if I was using two motors, by rotating them in different directions I could turn the vehicle in all direction required.
Thanks
Marcello |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 466
Registered: 10-2004
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| Posted on Wednesday, April 25, 2007 - 9:36 pm: |
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Marcello,
Will it be 4-wheel drive or will you have casters on the front. The main reason for asking is the increase in motor power needed for 4-wheel drive. If you put the drive wheels in the centre with casters front and rear, you can get away with lower power but the risk of grounding on rough terrain increases.
If not using RC, do you intend to control the robot using a control box linked via a cable to the robot?
Regards
Paul |
Marcello Marabese (Marab)
Member
Username: Marab
Post Number: 24
Registered: 8-2006
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| Posted on Thursday, April 26, 2007 - 12:03 pm: |
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Hi
Paul,
I had the idea of having two motors at the back, and one wheel at the front, the wheel at the front would operate like a shopping trolley wheel (if you get what I mean) as it can turn in all directions. The robot will be autonomous; I will program a micro controller to operate the vehicle. |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 469
Registered: 10-2004
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| Posted on Thursday, April 26, 2007 - 9:03 pm: |
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Hi Marcello,
That sounds fine for your method of steering. Autonomous - nice!.
I would suggest 1450-321 with 10" wheels which will give 4 mph and plenty of ground clearance. they are small and have a rather nice planetry gearbox on them. I would suggest 2 off 20A 'H' bridge controllers 1502-010 although with care and a bit of heatsinking, 1 off our 1502-001. Both of these controllers will accept I2C input allowing simple interface with a microcontroller.
Other geared motors we have are larger and will offer lots more power, more than you need by a long way and would need small wheels (100 to 150mm). Check out the above suggestions and see what you think.
Regards
Paul |
