Individual Rotor Control Capability

Hello everyone,

I’m a grad student at a university and we are looking to get a quadcopter platform to do some research with. We specifically need to be able to access individual rotor speeds, as opposed to only directional movement. For example, we would like to be able to have the platform hovering, then cut one engine speed to, say, 50% and then continue from there. I was wondering if this was something the Pixhawk has the capability of giving us.

I apologize if this is the wrong place to ask such a question, I’ve been looking around and have yet to find a definitive answer.

Many thanks!

You can send a specific value to a given motor by calling HAL->rcout.write(motor_id, value) directly but the AP_Motors library calls it continuously to maintain flight so it’ll almost immediately overwrite your value.

You canjust make AP_Motors or maybe the HAL output scaled / offset values to a specific motors, that should be quite easy. But as long as you’re in a self stabilising mode the PID is gonna react immediately and boost the input to the motor when it sees it has just half the thrust, so there may be no visible effect anyway. I suppose it would be different in acro mode, if you have the skill to hover in acro mode.