Ultimately we’ll buy Electronic Speed Controllers (ESCs) for our Quad motors. They take PWM in and produce drive voltages for brushless DC motors. Let’s jump in to understand the motor-propeller subsystem on a quadrotor. DC Motor Modelling You’ll find basic DC motor equations in any undergraduate dynamics textbook. I add the Bouabdallah model for the …
In the last quadcopter post we clarified the load torque of the propeller applied through the gearbox to the motor shaft. We won’t even have a gearbox but the terms in the equation needed clarification. We haven’t yet covered the main point of the propeller: LIFT! A propeller blade is just a spinning wing at each …
The equations below are from the last post, where we see we matched our Bouabdallah paper‘s equations for rotational motion. We know some propeller input is going to be a part of the applied torque. There is going to be a set of equations for linear motion too, but let’s clarify what is going on …
This post explains how we determine propeller thrust and drag factors for our quadcopter project. The last couple of posts have been working out the sum of torque on our quadcopter. A few weeks ago, we covered the gyroscopic effect of the total airframe in the “equations of motion” post. Next, we looked at the …
In a previous post we got the Ardupilot simulator stable running the linear-quadratic attitude controller, but we had a hack in-place for normalizing our body torque commands from Newton-meters to -1 to +1 for input to the Ardupilot motor sub-system. Purpose This post uses a test stand to measure maximum available thrust over a range …
In a recent post we used the Tyto 1520 test stand to get at a maximum thrust available from our motor-prop system. We want that maximum thrust so we can normalize our LQ controller command output for the Ardupilot motor command as outlined here. The Tyto 1520 offers great value for under $200. While we …