I saw that the behavior is different between the high, low and center position. sometimes the PID is correct bottom-center and bad from top to bottom or vice versa ....
That is because you are trying to convert rotational speed to linear speed. The Rotation speed is constant, but when it goes near the edges (up and down) the Linear speed is reduced, as well the load is getting less on the motor.
The 6DOF software fixes difference in speed by applying faster speed for the edges and lower speed for the center using some math for rotation speed calculation (COS,SIN etc)... For your 3DOF you use raw position data from the games that do not take that in consideration. I might have to integrate that kind of math in the firmware eventually for accurate distance and speed on such arm-rod actuators.
all simulators with cam and crank on this principle have this problem. My 2 DOF simulator has the same problem.
what is different is the length of the cam 24 cm here. and a speed of 30 rpm. but my 2 DOF at this speed (100 Hz.)
I did not know you would correct this for 6 DOF.
it's not a big problem in games, but it's more problematic for the PID. this makes three different thresholds for PID, up, down and center. it is on these three position that there are large variations.
fabi suggested to have variable PID settings according to the position to compensate for this deviation. I'll try to see if I can make the PID adjustable based on the position of the arm on the arc (perhaps using some math) to adapt the PID to the waveform shape of the actuator output and allow same stability level on all positions:
As you can see, when you increase the "Sensor oversample" to 5, the motors keeps bouncing on the target. That is when you need to decrease P term and decrease the on-line/offline speed of the motor (LCD menu values).
Please try with lower values for motor speed... I see you still run the motor speed in 100%... Also it might help decrease the max RPM value on the VFD side...
dureiken: Hi there, it's really quiet here someone could help me for my 6 dof project ? thanks a lot
Aug 8, 2017 15:34:46 GMT
tronicgr: dureiken Hi, Open a thread and I'll try my best to help. A little busy with Kickstarter details at the moment but I'll see what I can do.
Aug 12, 2017 11:57:42 GMT
dureiken74: I just did it
Aug 27, 2017 11:59:06 GMT
fimmy: How's the firmware going?
Sept 6, 2017 8:34:43 GMT
tronicgr: @fimmy I had to put it on hold to finalize the manufacturing of the new kickstarter controllers. I tested parts of it to ensure compliance with the new features and looks good so far. I'll get back to it soon for integration.
Sept 9, 2017 12:52:35 GMT
Theuns: Very nice design.I'm also busy with mine and changing it also to Linear Actuators with 220v Servo motors.I'm waiting for my new controllers from Thanos. If I may ask Do you have any Sketchup files of your design and willing to share it I Thanks Theuns
Sept 14, 2017 22:45:09 GMT
atayeu: Hey everyone! I'm reading up and gathering all of the intel I can find for my first motion platform. this is by far best information for creating one.
Oct 14, 2017 7:25:57 GMT
tmcnam: I must be crazy but I still can't find the blueprints to the platform by GA-Dawg. Any help would be appreciated. Thanks guys.
Mar 10, 2019 21:31:57 GMT
Trip Rodriguez: Sorry tmcnam, the shoutbox doesn't get much attention. Did you find the blueprints? They are at the VERY bottom of the extremely long first post. It says "attachments: 6DOF.zip
May 4, 2019 19:13:25 GMT
zivby: How much weight this setup can carry?
May 19, 2019 11:57:16 GMT