Octomecanum Shifting Question

[Aren_Hill]

Originally Posted by orangemoore

I am currently trying to design a Octomecanum drive train for fun and possibly as a drive train for my team to use in the future and I have come to a point where I have gotten a little confused. Every example uses pneumatic cylinders to shift from mecanum to tank and I was wondering how people prevent the pistons from bending due to the stress. If anyone who has experience with this or some insight that would be really helpful.

Optimally your piston should be a simple two force member, that is, only experiencing direction extension or compression loads. Many times this is accomplished via ball joint fittings, or having enough play in its pivot that it doesn't take any load.

Keep check on load paths through the module and it should be easy enough to be sure the piston isn't taking any bending loads.

-Aren

[AdamHeard]

Originally Posted by Aren_Hill

Optimally your piston should be a simple two force member, that is, only experiencing direction extension or compression loads. Many times this is accomplished via ball joint fittings, or having enough play in its pivot that it doesn't take any load.

Keep check on load paths through the module and it should be easy enough to be sure the piston isn't taking any bending loads.

-Aren

To expand on Aren's points, if the cylinders are loaded as he described the rod size is spec'd such that you won't ever fail a cylinder from it's own force.

[mman1506]

Originally Posted by Aren_Hill

Optimally your piston should be a simple two force member, that is, only experiencing direction extension or compression loads. Many times this is accomplished via ball joint fittings, or having enough play in its pivot that it doesn't take any load.

Keep check on load paths through the module and it should be easy enough to be sure the piston isn't taking any bending loads.

-Aren

A somewhat related question: Does 148 (or neutrino) implement a encoder into their butterfly drive?

[Aren_Hill]

Originally Posted by mman1506

A somewhat related question: Does 148 (or neutrino) implement a encoder into their butterfly drive?

Neutrino ran last year with no sensors on the drivetrain, but still had a 7 disc auto

[DampRobot]

Originally Posted by Aren_Hill

Neutrino ran last year with no sensors on the drivetrain, but still had a 7 disc auto

Did they just do gyro PID and then drive for set times?

[MichaelBick]

Originally Posted by DampRobot

Did they just do gyro PID and then drive for set times?

I doubt they used gyros. Their butterfly allowed them to drive straight without PID.