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Control precisely speed of two motors and wheels

Posted: Wed Jun 02, 2021 8:27 am
by FPI
Hello,
I need to control the speed of two wheelchair motors of 300W / 24V, 120 rotation by minutes, with 26 cm wheels on each.
I think to use :

- Phidget Encoder HighSpeed 4-Input board
- 2 Optical Rotary Encoder HKT22
… connected through USB to a Raspberry Pi 4 and Nodejs language.

Do I need something else to do that ?
download/file.php?mode=view&id=1326

Best regards

Re: Control precisely speed of two motors and wheels

Posted: Wed Jun 02, 2021 8:32 am
by mparadis
Your diagram doesn't show how you'll be controlling or powering the motors. The 1047 only reads the encoders.

The 5V and G pins are outputs in case you need to attach limit switches or other small devices. It gets its power from the USB connection so you don't need to hook these up.

Re: Control precisely speed of two motors and wheels

Posted: Wed Jun 02, 2021 8:37 am
by FPI
Hello,

Motors are powered by two batteries (35 A) through Saberbooth 32 A (it works well).
Raspberry drives the Saberbooth through PCA9685 16-servos board.

So, Is the "Phidget Encoder HighSpeed 4-Input board" powerd by USB wire ?
Does the Raspberry ¨Pi 4 USB port able to deliver enough currrent ?

Best regards.

Re: Control precisely speed of two motors and wheels

Posted: Wed Jun 02, 2021 8:52 am
by mparadis
For our USB Phidgets, some customers have had power issues with the Pi's USB ports. You may want to use the VINT Hub and two ENC1000s instead, they're newer devices, lower power, and altogether less expensive.

Re: Control precisely speed of two motors and wheels

Posted: Wed Jun 02, 2021 9:05 am
by FPI
Hello,

I choosed the "HighSpeed 4-Input board" because the text "allow to read simultaneously several encoders"....
So do you think that I can do the same with following schema ?

download/file.php?mode=view&id=1327

Best regards.

Re: Control precisely speed of two motors and wheels

Posted: Wed Jun 02, 2021 9:57 am
by mparadis
Yes, this schema will work with both encoders simultaneously and won't have any USB power issues.