A quick update on my project, adapting an old stationary racing rig. Arduino/motormonster control with wiper motors.
The frame was constructed by a friend, slightly improved from my drawings.
I originally drew a rectangular base, but he came up with the X design. NICE!
I found that the motors were positioned too close to the axis point making them struggle and giving the rig way too much movement.
Moving them back and adjusting the balance again cured that problem.
I originally had the Pots attached direct to the output of the wiper motor but soon found this gave too much movement, this could be adjusted with the software but limits control. I overcame this by using a couple of pulleys and a belt.
Overall this seems to work pretty good, to be honest i still think the rig moves too much and the motormonster cuts out sometimes, i suspect its over heating. I have played around with the PID settings but don't understand the adjustments. (i would appreciate it if anyone could give advice on this please)
I am also tempted to move the motor linkages even further away fro the axis, to reduce movement and load on the motors.
I am still in the test stages and will update when I get any improvements.
Here is a video of first tests, a little rough, movement has been calmed down since then.
[YouTube]https://www.youtube.com/watch?v=D74i3CLo1t8[/YouTube]
https://www.youtube.com/watch?v=D74i3CLo1t8
Many thanks to all that contribute to this site, projects like this would be impossible without your help.
***UPDATE***
I have since removed the original racing rigs steering wheel mount bar and built a new frame to hold the wheel. this was to remove the bar that sits between your shins.
I also found that the belt driven pots could drift slightly, causing the stop position to loose calibration.
so I constructed a direct link to the pots from the frame.
this seems to work really well, and perhaps slightly more responsive. it also gets over the problem of connecting the pot to the motor which can be difficult.
Its worth spending time getting this bit right, you need to use as much of the pots rotation as possible, but not over do it as you will damage the pot. That was a positive with the belt system, the belt would slip instead of the pot getting damaged.
Consider the pot will need to turn around 270degrees where the motor output will need only 180degrees at max. getting the gearing correct for this seems to make a lot of difference.
***UPDATE***
I still found problems with rig overshooting the pots, this caused the gears to slip and I would loose calibration.
To overcome this problem I decided the connections between the motor and the shaft would require some kind of clutch mechanism, but with the ability to spring back to centre after slipping.
I tried various different ideas using gears and springs but these were unreliable.
My final idea that seems to work really well was to connect 2 gears together like a clutch, but the gap between the clutch plates are joined together by a thin layer of silicone sealant. This allows the clutch plates to slip if the motor overshoot the pot but the clutch will spring back to its original centre position.
SitemapIndex
RSS Feed