4DOF hybrid motion platform (electro-hydraulic)

[DoctorD]

@vicpopo
Thanks for the kind words.

I agree, safety and control are VERY high on my importance list for this project. I used to work on aircraft and I am approaching this with the same attitude.
These machines we build can very easily hurt (even kill) the occupants and/or those around them - hence why we shouldn't compromise on safety in order to save a little time, money, etc.

lol about the droids

Thanks for the luck too!

[DoctorD]

A bit of an update...

Have spent the weekend sorting out the force profiles in X-Sim. Fingers crossed I followed the tutorials correctly (seemed simple enough). Sadly, the 3D virtual modelling program (Simforce GT) doesn't work on any of my PC's - so I'll just have to rely on physical testing in the next fortnight.
I've got a little bit of electronics to complete (some logic inverters to add to the safety circuits) and then there's the matter of coding the Converter output to drive the Servo Drivers.

In the meantime - here's a shot of the hydraulic components that will some day add extra force to the steering racks.
All four of the power steering racks, the two power steering pumps and the harmonic balancer/pulley come from the vehicle below, the 'not-so-small' Dodge Ram 3500:

Dodge3500.jpg (70.99 KiB) Viewed 5171 times

Dodge Ram 3500 (Source of components used)

HydraulicSystem.JPG (168.31 KiB) Viewed 5170 times

Hydraulic System Components (Pumps, flywheel/Pulley & Motor)

The 'assembly' attached to the front of the pump is a custom machined 9kg flywheel and balancer/pulley (which will store a very large amount of energy for use during simulation). I intend to store this inside a very substantial enclosure for safety (9kg @ 1500rpm could get very nasty if things went South).

Also, here's a quick test of my Inventor model - showing how the actuators and joints function in the system.



Hopefully have more soon.

[DoctorD]

PREDICTED MOTION RENDER
Predicted safe operational speed and maximum travel display




Another 7-14 days and I'll be able to show you the real thing hopefully...

[vicpopo]

Hi ,

Really realistic simulation !! Good progress building your simulator

[tronicgr]

Really nice simulation indeed! Are you using the Autodesk Inventor CAD? Which version? From a quick loon in their site I see the over $1200 to get a licence for it!

Best Regards,
Thanos

[DoctorD]

Hey Thanos,

I'm using Autodesk Inventor Proffessional Suite. I use it at work for design and yes, it is very expensive. I think we pay around $4000 a year per computer for the privelage :/
...it really is amazing software though. Surely makes light work of some tasks (and saves a lot of time during design).

I'm pretty sure you don't need the full design suite to do this sort of stuff. I think the 'standard' Inventor will do this just fine.

I'm happy to help you out with 3D work if you need it in the future

Best regards,
DoctorD

[DoctorD]

Getting super close to integrating my arduino with X-Sim!

I spent the weekend completing the safety circuitry for the platform. It's rigged up so that if any of the following events occur, the motor drivers go into fault mode and the motors are isolated from power if:
- any of the 4 actuators travel past the end stops (microswitches)
- any of the emergency stop buttons are pushed (3 in total: 2 on the platform, 1 on the wall)
- the motors draw too much current (I.e. If an actuator gets jammed)
- the motors don't go where they are commanded (encoder feedback checks)
- any of the upper or lower mechanical universal joints break or come loose

Now that it's safe, the next thing is to write the start-up and calibration routine for the 4 actuators (so they know the total allowable travel and mid-points before operation). This will also position the platform for rider mounting.

After that I'll have to convert the X-Sim output values into positioning cues that the 4 servo drivers can understand.

...then it's video time

[RacingMat]

Everything looks under control!
Very good job DoctorD