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#1
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pic: Shifting Module for Drivetrain Concept
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#2
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Re: pic: Shifting Module for Drivetrain Concept
Ok, I'm going to bite. Any reason why you aren't using the gears out of AndyMark's gearboxes and saving all that machining? They have some pretty nice ratios. You can make custom side plates, use the final chain reduction to get any speed you want at the wheels, etc.
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#3
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Re: pic: Shifting Module for Drivetrain Concept
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#4
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Re: pic: Shifting Module for Drivetrain Concept
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#5
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Re: pic: Shifting Module for Drivetrain Concept
When you run a two motor set up as mentioned, one motor will be running in reverse of the other, causing an efficiency loss and one motor spinning a bit slower then the other.
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#6
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Re: pic: Shifting Module for Drivetrain Concept
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#7
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Re: pic: Shifting Module for Drivetrain Concept
They will absolutely be running at the same speed (at least I hope so
) but they may be at different points on their performance curves, if these curves vary based on direction. This means you aren't necessarily at the peak power of each motor (not necessarily affecting efficiency...). However, the directional bias of a CIM is certainly small enough to disregard (if it exists?). |
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#8
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Re: pic: Shifting Module for Drivetrain Concept
I thought the same thing that they should be the same speed, I was just told by some members of my team that the difference in preformance is great enough between 2 cims that a noticeable amount of preformance is lost when they are linked together. I find that hard to believe, but thats why this has 4 seperate transmissions to appease that belief. The pros of simply using a Supershifter will be raised. Yes the motors are being coded to run at the same speed, it is merely electrical differences within the construction of the motors that will create slight variations. Thats my understanding at least. However I am much more mechanically inclined as opposed to electrical/pneumatics, so I could be totally wrong.
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#9
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Re: pic: Shifting Module for Drivetrain Concept
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Last edited by lemiant : 27-08-2011 at 01:10. |
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#10
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Re: pic: Shifting Module for Drivetrain Concept
And besides, even with separate transmissions and all, you still have both wheels on the ground that have the same constraint on them: they must spin at the same speed. The only thing separate transmissions accomplishes is the possibility of independent motion of the wheels, which would only shred your treads unless you had mechanum.
Motors in the same gearbox are USUALLY going the same direction just because of how they are usually geared together, but it is possible to have them switched, by putting them on opposite ends of a shaft or by having an even number of gears between. In fact, one widespread instance of counter-rotating motors this year was minibots. The wheels obviously had to spin at the same speeds, just in different directions (or the motors were often on different sides of the wheels, if the wheels were both on the same side). |
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#11
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Re: pic: Shifting Module for Drivetrain Concept
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#12
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Re: pic: Shifting Module for Drivetrain Concept
AH, got my motor types wrong...whoops.
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#13
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Re: pic: Shifting Module for Drivetrain Concept
I'm confused. What doesn't apply to super shifters?
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#14
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Re: pic: Shifting Module for Drivetrain Concept
Unless your wheels are scrubbing, the motors are "fighting" each other just as much. If we assume the wheels, gears, and chain runs are all exactly the same then the motors, even if though they are in different gearboxes will be spinning the same speed, unless your robot is sliding.
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#15
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Re: pic: Shifting Module for Drivetrain Concept
In that post I am referring to special cases that have the motors in one transmissions spinning opposite directions. They exist, but aren't really relevant because he will be using supershifters. And supershifters do spin the motors the same direction.
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