VEX IQ DriveTrains

Does a four motor drivetrain automatically move faster than a two motor drivetrain`

no… it does not. it simply has twice as much power.

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torque is what is doubled “automatically”, not angular velocity

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it will however have faster acceleration, which means you can make smaller movements faster. so in the long run, depending on how you drive you might end up scoring faster with a 4m drive compared to a 2m drive.

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The motor limit in IQ is 6, so in most cases, I would not recommend this approach.

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Yup. If you’re going to use a 4 motor drive train, use an x-drive

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what is an x drive 20 char

i know but ive already made my competition robot and i can have a motor drivetrain because i am only using one other motor

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Then that’s definetely what you want to go for! Nice job with that! That’s the goal of any iq robot. Having a good robot with enough motors to spare for a good and maneuverable drive train.

x drives are a type of drive with the ability to strafe. they are drives with wheels pointed different angles than the normal tank drive (most x drives have wheels 45° angles, but it’s possible to make x drives at different angles resulting in a different MA).

anyways 45° x drives have a linear velocity sqrt2 times higher than that of a tank drive with an equivalent RPM and wheel diameter in the orthogonal directions (and a 1:1 MA compared to a tank drive of the same wheel size and rpm, but half the power, in non-orthogonal directions). with that said, all that’s inherently special about x drives is their ability to strafe and their ability to independently turn while moving. changing the wheel angle is just another way of changing MA just like gearing is (and of course, when decreasing MA to increase speed, you obviously suffer a proportional loss in torque because the two are inverses; power = angular velocity times torque). not that it’ll likely apply to anyone here, since no one rly uses any angle other than 45°, but something to note when changing wheel angles is that the MA in certain directions is different. they can be calculated pretty easily with some basic trig

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Has anyone successfully put together X-drive code in VexCode Blocks?

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not yet but i will soon- i am basically going through all of the different drives, seeing which one is the best for me to use and program- the most complex one ive seen is an asterisk drive, a mixture of x and h drive, really complex. Gonna have a hard time programming that one :wink:

most complex drive design you’ll see in vex is probably gonna be a diffy swerve

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idk- personally, i think asterisk is harder

I just looked at the asterisk drive, and it works using 6 motors which wouldnt be that usefull in VEX IQ considering the motor limit (also its not more complex than a diff swerve).

One more thing to mention with the asterisk drive is that it uses 2 different sises of wheels to combine speed and torque (correct me if im wrong here I didnt really pay attention to the video) which also would not be possible in vex IQ as there is only 1 size of omni wheel.

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a diffy swerve can become an asterick lol. it changes the orientation of the wheels

not how it works. torque and speed are always traded off when under the assumption of constant power

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No it does not.if you have a robot with a 2 motor drive geared up to 3:1 for example it will go faster than a drive that uses a 1:1 drive but has 4 motors rather than 2. but if you have a 3:1 drive with 4 motors it will probably go faster tan a 3:1 with only 2 motors because you will have more torque and power to move your wheels so less strain that the motors have to make up for. also if you are using 1 motor for a certain task for example for a lift then i would suggest that you us a second motor to be able to do that task faster and more power. for example in next level many teams used a 2 motor lift in order to lift much faster while others used a much slower 15:1 in order to have a strafe. but all the best teams used 2 motors for their lift so that they could go up and down more often in the 1 minute time span.

i agree- i jusrt wanted to see what i can program in order to enhance my skills :grin:

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