Classical and Modern Controls Experience
During my time with Portland State, I discovered a passion for control systems. Taking all the classes I could, I gained experience with classical control methods, PID, etc and modern control techniques even applying state space methodologies to digital systems. Additionally, I gained a better understanding of observability, controllability, stability, and feedback by taking a course in advanced controls mathematics.
​
Below are some samples of projects and exercises related to controls.
Controller Design
Experimental System Identification
Given a locked simulation system in Simulink I was tasked with finding the system transfer function and designing a controller to improve the system response while adhering to realistic controller constraints.
​
My first step was to create an experimental Bode plot. I wrote a code that would step through a large set of frequencies, sending a sine wave through my "black box" machine, record my phase shift and gain and then assemble it into a Bode plot. This task was non-trivial but I enjoyed the challenge of automating this task rather than doing each frequency by hand.
Building a Transfer Function
Through several iterations, I built a transfer function by strategically adding poles and zeros. Eventually, I created a TFÂ whose bode plot matched my experimental system fairly well. Now onto my controller design.
Simulink
I also had the opportunity to model dynamic and unstable systems in Simulink. Here is a model of a heat exchanger system. This was a final project for my advanced controls class. I was to find an existing controller design in literature, with a well-defined transfer function, model the system in Simulink, and then design a controller to enhance system performance.
​
One controller component I attempted to utilize was the Pade approximation for time-delayed systems. This heat exchanger had a significant time delay between the sensor and the actual time of heating. Using this created marginal gains when compared to a standard lead controller.
DC Motor w/ Weighted Flywheel
Position Control
PID Control Experiment
This is some experimental data comparing different controllers and their actual response to sinusoidal input signals. These experiments were done in my mechatronics class. It was very cool to see these controller output signals and how they vary throughout the course of the input wave. It was very interesting to see the controller saturate at +/-10V during more aggressive controller. designs.
Digital Signal Processing
Using a butterworth to filter IMU data. Observing the differences in cutoff frequency based on butterworth parameters.
