pic: Drivetrain Concept

[XaulZan11]

Originally Posted by Bryce Paputa

1625 made a gearbox a while ago (offseason of 2010 or 2011) that did this, unfortunately I don't remember what it was called to search for it.

1625 called it a Lobster drive in 2011.

51 did an H drive in 2011. 217/148 did a similar drive in 2010. I'm sure there are others that I'm forgetting.

[Bryce Paputa]

Originally Posted by XaulZan11

1625 called it a Lobster drive in 2011.

51 did an H drive in 2011. 217/148 did a similar drive in 2010. I'm sure there are others that I'm forgetting.

I was talking about the CIMs as spacers idea, but I was able to find it, http://www.chiefdelphi.com/forums/sh...ad.php?t=86668

[echin]

I'm almost done with the next revision and I'll post a picture when I'm done (I'll be gone for the rest of the week so it might be a while). I changed the center wheel to a pivoting piston actuated system instead of linear spring loaded, which saves some weight. I also removed the back wheel module and changed the drive to something more like 624's grasshopper drive. This requires the drive to tip at an extreme angle to use the traction wheels and only saves a little more than 1 lb, so I may change it back to more like what I had before.

An H drive would be able to drive like a swerve with some fairly simple programing, so why does it seem like most teams using H drives don't drive them like swerves?

[randantor]

Originally Posted by echin

An H drive would be able to drive like a swerve with some fairly simple programing, so why does it seem like most teams using H drives don't drive them like swerves?

We experimented during build with field-centric drive controls for our H drive. The difference in power between the X and Y drive directions meant that it wasn't particularly useful because the robot still needs to be pointing forwards to go at any decent speed for travel. Also, our team specifically isn't able to get access to a decent-sized area for driver practice very often, so the additional time needed for our driver to get used to it didn't seem worth it.

[RyanCahoon]

Originally Posted by randantor

We experimented during build with field-centric drive controls for our H drive. The difference in power between the X and Y drive directions meant that it wasn't particularly useful because the robot still needs to be pointing forwards to go at any decent speed for travel. Also, our team specifically isn't able to get access to a decent-sized area for driver practice very often, so the additional time needed for our driver to get used to it didn't seem worth it.

What are your thoughts on using something like Ether's Halo Auto-Rotate controls with an H drive?

[randantor]

Originally Posted by RyanCahoon

What are your thoughts on using something like Ether's Halo Auto-Rotate controls with an H drive?

After offseason modifications, our center wheel is now pneumatically actuated, so it isn't in contact with the floor when we aren't trying to strafe. There is a noticable difference in acceleration when the wheel is down because we lose weight from the other wheels. The center wheel output follows a half-second ramp from 0 to full power, and the time that it would take for it to add any useful speed is much longer than it takes for the robot to just turn without it.

[Tyler2517]

Originally Posted by echin

I'm almost done with the next revision and I'll post a picture when I'm done (I'll be gone for the rest of the week so it might be a while). I changed the center wheel to a pivoting piston actuated system instead of linear spring loaded, which saves some weight. I also removed the back wheel module and changed the drive to something more like 624's grasshopper drive. This requires the drive to tip at an extreme angle to use the traction wheels and only saves a little more than 1 lb, so I may change it back to more like what I had before.

An H drive would be able to drive like a swerve with some fairly simple programing, so why does it seem like most teams using H drives don't drive them like swerves?

A swerve drive has 100% thrust vectoring. An h drive will almost always be weaker moving in one of its directions. It may be faster accelerating in one direction then a swerve but a swerve can accelerate the same rate on all directions making holonomic motion easier.