Author: mtimmons

Quad-Rotor Control Design Series

Quad-Rotor Control Design Series

What is a “quad-rotor”? Well you probably know it’s a thing with four rotors. We buy it as a, “drone” and we fly it with a remote control or via a phone app acting like one. I’ll probably bounce between the terms quad-rotor and quadcopter throughout. I mean the same thing. It is incredible what …

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QuadCopter Dynamics and Controls: Ramp-Up Reading…

QuadCopter Dynamics and Controls: Ramp-Up Reading…

I started to sketch a quadrotor model myself and derive the equations of motion, but I lost confidence and figured it would be best to sample the literature first. Below is a list of papers I found online. Click the links to see the papers. All the papers are useful, but I found the, “PID …

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Dynamics and Controls Study Materials

Dynamics and Controls Study Materials

I’ve enjoyed great opportunities to both study and work on mechanics, electronics, real-time control systems and supporting software for automated machines: Agricultural machine control for the most part, and some neat control systems problems in communications, sensors,  and other areas. Dynamic Modelling One thing I really like about, modelling a dynamic system is you need …

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QuadCopter DC Motor(BLDC) + Propeller Dynamics

QuadCopter DC Motor(BLDC) + Propeller Dynamics

I decided to start on the inner loops. By this I mean the control loops for each propeller drive system. A Brushless DC Motor (BLDC) is standard for hobby-sized quadrotors, so let’s assume the motor type. I haven’t sized anything yet: propellers or motors, but I can get the dynamic model figured out and put …

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Useful German History: actual Nazi’s and Fascists…

Useful German History: actual Nazi’s and Fascists…

There’s a long-running, humorous tendency for people to label politicians or social forces they fear as being, “Nazi”, or “fascist” or to compare this-or-that person to Hitler. There is even a funny, “law” on the subject (Wikipedia: Godwin’s Law. ) By my observation it is somewhat like the ad hominem attack in debate. This is where one …

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Open Forum

Open Forum

If you have a problem to solve and you’re looking for ideas, or maybe you want to challenge me to start a blog series on a new problem that you think we should tackle, please comment here! I encourage any students with interests or questions about any engineering or science field to inquire here. I …

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Quadrotor: 4 props to stabilize the platform

Quadrotor: 4 props to stabilize the platform

In a recent post I shared a mathematical model for the combination brushless DC motor (BLDC), gearbox, and propeller model. A small quadrotor motor might not have a gearbox. It might have the propeller mounted directly to the shaft of a small hobby motor. A gearbox helps match the motor to the load: the propeller. …

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Revisit the Motor-Propeller Model

Revisit the Motor-Propeller Model

It was fun to mess with the motor-propeller differential equation and linearization in my earlier post. However, when I got into looking-up some rough parameter estimates and performing dimensional analysis (seeing if the units worked-out right for me in the equations) I ran into some problems. I realized I was not only needing numbers, but …

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Propeller Blade, “Lift”

Propeller Blade, “Lift”

In  the last post I was able to clarify the load torque of the propeller applied through the gearbox to the motor shaft. I haven’t yet covered the main point of the propeller: LIFT! A propeller blade is just a spinning wing at each cross-sectional location. The propeller force described in the NASA diagram in an …

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Quadcoptor Platform Equations of Motion: Dynamic Model

Quadcoptor Platform Equations of Motion: Dynamic Model

It’s been over one month since I last posted. Back then I took a journey into fluid mechanics to offer a glimpse into how propellers work. I was motivated to do this as I was previously working-out the electric motor and propeller dynamics when I started to recall my mechanics studies. It’s a good time …

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