Bidirectional Application

[jfi...@mtu.edu]

I am trying to find a way to use the beaglebone blue for bidirectional power flow. I need a connected DC motor to act passive as well as active at different times. Can the beaglebone blue do this, and if so how does it work?

[Dennis Lee Bieber]

On Mon, 11 May 2020 10:10:50 -0700 (PDT), in
gmane.comp.hardware.beagleboard.user jfiore-Cg...@public.gmane.org
wrote:

To me "passive" DC motor implies it is being driven in reverse; that
is, the shaft is being spun by some external force, and the wiring is
producing a voltage (acting as a generator). Obviously, that would be
unsafe on most Beaglebone GPIOs due to the risk of exceeding 3.3V limit.

However, a Google search finds this
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=2ahUKEwi9q7KMiK3pAhUNUa0KHTt1D5EQFjACegQIBhAB&url=https%3A%2F%2Fapm.iitm.ac.in%2Fbiomedical%2Ftouchlab%2Fpapers%2FDCMotorDamping.pdf&usg=AOvVaw3BCcXZjRyGDN6Nat5M4ppT
which indicates that a particular H-Bridge configuration is needed to put a
motor into a "braking" mode. If using the Blue's H-bridges, and the Robot
Control Library, then this would be done by invoking rc_motor_brake()
http://strawsondesign.com/docs/librobotcontrol/group___motor.html#ga470369dde3e084f0a2a5c99db61f9494
(vs rc_motor_free_spin() to coast).



--
Dennis L Bieber