Servo Driven 2DOF

[eaorobbie]

Well here goes seem Pololu is the feature product of the month

First I built a small model to test wheather I could make it all work.
Main Items were two Hitec Hs55 RC Servos, Ubec to filtler power for servos, 3/8" Socket uni joint for pivot point, and a Pololu RC Serial Controller.

Once hooked up like this(sorry pic a litle rough but give ya the idea) and couldnt find pic of RC Serial card,Pololu informed me they dont make it anymore and the Maestro does the same job with a virtual com port over usb.



And ended up working like this, but servos werent really suited just a little small or I change them out for Futaba S148's and now mimics my finished sim nicely therefore I can test my profiles first on the model without running my full sim and know how the full sim will react.



Then I First tried to use 2x Car Wiper motors ,2x Single Turn Pots ,2x Pololu Jrk12v12s and a Pololu RC Serial Controller
Once hooked up like this.



Then decided to just build one and test the unit on the desk. Resulting in



Once I sorted out the overshoot with the pid calc and was happy with setup I moved forward and built the second unit then run a test.



Then installed them onto a simple seat in this configuration.



A simply test run.


But had alot of problems with the joint connections and balance so I changed it around a bit to look like this, tidied the wiring plus heatsinks on Motor Controller Chip.



Which produced a fair movement in the sim but i wasnt happy with the results to fidily in setting profiles for different mods and wiper motors eventually had lot of backlash in the gearing very quickly.



So I did alot of digging and asking and found I controller quite a large motor, a 900kg/2000lbs 12v Boat Trailer Winch and set it up like this.



This was the first test to see if it work, amps were restricted to 4amps due to power supply and pots are a little cheap plus speed set to only half all done in the supplied Pololu Configuration program.



And a video of nearly finished sim.



After a while of using and playing with the setups I found the pots not to have enough movement for render enough resolution to feel the small bumps and quick flicks as if driving one side of the car onto a ripple strip. So I found some five turn rotary pots and managed to attach a gear from a rc helicopter main rotor and drive this from the motor side of my boat winch, and wow big difference in feel, alot smoother and finer.
Then discovered I could talk to the cards directly from X-sims USO, bigno no RC Card needed one less card to think around, response time came down nicely.
Then found a generic benchtop power supply that had a 20amp load and 40amp peak,
well i had to turn alot or about 1/2hrs driving felt like ten rounds with tyson, ya need help to stand, what a work out. Brings back memories of speedway racing as a kid.
And a big thanks to everyone that has posted here without this precious information, I would have near thought I could electrophy a sim pit. So cheers Guys

New vids and pics will follow as time lets it.
Happ sim ing guys, Im addicted

Robbie out.

[egoexpress]

Congrats

Comparing both setups, I think you could have resolved the shakiness of the first one by setting the max value for the effects higher.
The winch motor setup is a little bit too slow and not responsive enough if you asked me.
Or would you be able to get some more speed out of the winch motors?

Regards

[eaorobbie]

Yea ya right egoexpress but the wiper motor gearing failed under the load. The winch setup in vid is only set at about 40-60% intensity because of cheap pots.
Getting more speed was achieve though raising the max amps (20amps) and max duty cycle in the pololu config program plus 5 turn pots to increase the resolution Then increased most of the effects to 100%.
Now looking at new motors for next unit as this was only a protype thats been always been changing. Cheers

[eaorobbie]

Well it's been a awhile playing, testing, changing but now very happy with sim action so as promised over the next couple of weeks i will release my drawings and guides on how to setup a unit like mine plus hopefully release a guide on using Jrks with X-Sim.

Sim Base PDF (Measurement in mm)

sim set base.pdf

Sim Base

(6.72 KiB) Downloaded 186 times

Sample of Jrk Guide.

Setting up a Jrk12v12 in X.pdf

Sample of Guide

(274.43 KiB) Downloaded 211 times

Sorry this will take alittle while, new job doesnt allow much tinkertime, If ya really stuck sent a yell out on MSN, I do answer all.

[bsft]

Nice job there dude.Just a suggestion, I stopped the backlash in my wiper motors using fairly heavy compression springs under my frame. I used big accelerator springs

You can see one near the uni joint. Two $5 springs create a more consistent load on the motors. It may take some of the jerkyness out, but it does the job, and no replacing motors all the time.

[eaorobbie]

Yep good suggestion bsft but hence the reason for me throwing out the wipers because after a few hours of extreme movements caused the internal plastic worm gears to wear badly. Even after adusting the backlash movement of the wiper they just began to slip and wear badly resulting in alot of the feeling of movement to be lost even with springs. Which I tried on my first seat rocker.
But in turn this problem lead me to discovering the winches and presto no backlash. Been thrashing them for 12 months with the only problem that occured, recently playing dirt2, was for the nut on the collor of the pot slowly working loose, inturn self adjusting the centre position. I thought my jrk was finally dying, checked all my setting, reset the feedback positions, but the problem was still there on centre position kept changing. So after alot of thinking and scratching, i went to remove the pot and found the nut loose, AH something so simple, Murphys Law got me again, Dont look for the complicated fix, just look at the obvious. Bugger.
All good now, will include a note in the jrk guide on springs thanks mate.

[bsft]

True about the motors and backlash. I destroyed two on the "roll" frame of my old joyrider, until I tried the spring solution. It works here,
http://www.youtube.com/watch?v=jcnekS96BKw
Feel free to use what info I supply for your jrk guide.
Cheers, David.