The Eccentric Engineer Mini-series Part 1: The Closed-Loop Feedback Loop

Well the title might be a mouthful, but I love it. I'm super excited to embark on a new mini-series that I've been interested in for all of 6 hours now, and I think it could be a nice break from the usual updates. I will attempt to marry engineering concepts and human systems, but I want to get right into it, so here goes. I promise I will explain it as I go on, and I'll try to make the concepts plain so we can get to the good stuff.

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Many people think of engineering, and their knee-jerk response is "eww, I hate math" or "lol I don't care, I just buy products, I don't care how they're designed or made", which are all fair! It's not for everyone, but something that I think a lot of people don't seem to realize is that engineering is both an art and a science, and it's made imperfectly by imperfect people. Yes, we try to design, analyze, and plan systems and products the best we can. But we also stick to the ole guess-and-check when we just don't know where to begin sometimes. I love engineering because it is so fundamentally human. We design, create, analyze, evaluate, then do it all over again, seemingly endlessly, chasing perfection, or maximum profit or aesthetics (I won't judge your priorities). If you think about it in terms of us as humans and how we grow, it's kind of the same thing, just a little tweaked to fit our context. Today I specifically wanted to focus on a kind of system that's really intuitive and will make a lot of sense, even for those who aren't engineering-inclined. (To be honest, I don't think I even fully understand it myself, but I'm going to do my best to do it justice). And if my controls professor is reading this, I apologize for all the errors you'll probably see. I promise I paid attention in class, it's just been two years since I took it.

Feedback is something that's very common in our lives. A parent telling a child they did a good job for cleaning their room, a boss getting angry when project deadlines aren't met, or giving our dog a treat for pooping outside instead of on our carpet. Most important for us in this context is that feedback is our way of telling each other that things are as we expect, or they are not. When we start to consider things in our lives as systems, we start to ask how we get from where we are to where we want to be. I've said system a few times without really introducing it, so I'd just like to say that the system I'm referring to here specifically is a system for helping myself and others work toward personal growth. It's not so much a rigid process or list, but rather an outline for thinking in a procedural way and understanding what elements play what roles. This will vary from person to person. A system can be considered open, where elements can be affected by external factors, or closed where everything inside the system is pretty much self-contained. A system has inputs and outputs, which are exactly what they sound like. We will consider the personal growth system to be closed for now, and I'll explain further in a bit.

A concept I'd like to introduce that I think is important to understanding the growth system that I try to use is the closed-loop feedback system. This is a pretty clunky name, so I'll break it down so we can have a richer understanding of it.

• Closed-loop: This just means that everything the system needs to subsist is contained within the system. It doesn't need any external items

• Feedback: Feedback, as mentioned earlier, is our way letting ourselves know where we stand compared to the expectation

• System: A group of elements that work together as a whole

Here it is in all its glory. The closed-loop feedback system. Isn't it beautiful?

Source: Introduction to Control Systems, p.75, Dr. Prabir Barooah, Aug 2016.

I'm going to walk through this in terms of the process of personal growth, and go over each element in doing so. I'll do it as an ordered list to keep it organized and as simple as possible. I just want to say right off the bat that these items in the list can be either numerical goals, which are easier to track, or just something you're working toward in a qualitative way.

1. Setting a goal: This is where this loop starts at r(t), which is know as the reference signal. This is what we want to achieve and is the ideal case. We know this most likely won't happen right away, but we will work toward it.

2. Evaluating where you are relative to your goal: Basically, where you currently are. If you're starting out, you'll probably not be too close to the reference, but you know that's where you want to be. The e(t) is called the error, but that's a bit loaded for this context. Error simply means the difference between the desired outcome and the current outcome. The goal is to minimize the error over time (minimizing steady-state error for you nerds out there).

3. Making an action plan: This is where things get kind of nebulous, because now it's up to you to decide what your plan looks like. If you want to, for example, be more honest with yourself about how you feel, your plan could be to journal and catch yourself when you're judging how you feel, which might keep you from being totally honest with yourself. This becomes your controller. The controller guides the action.

4. Putting the plan in action: the actuator refers to the thing that's driving the action. In the example mentioned above, it would be actually sitting down and journaling or whatever your method is. It's putting the pedal to the metal. You are the actuator. Make something happen.

5. Process in this case just refers to sticking with the plan and actually doing it.

6. The process will produce an output, y(t), that will be measured by a sensor. Here's where things get interesting, as this is really where the feedback comes in. The output goes through the sensor, which is where it is sensed and fed back into the loop. This is the system's way of knowing what the current state is. Example, the output of journaling every night may make me feel more at ease and less judgmental about feeling what I feel, allowing myself to feel better than I have.

7. (Back to the beginning) The output goes back into the system into the circle, and the difference between the output and the reference is used to drive the system again.

Now I'll walk through it with a full fleshed-out example. Note that I will use the qualitative method to show that the more difficult growth points still apply to this. Things involving numbers are easier.

1. Goal: Feel more at ease in my own skin for feeling how I feel about things

2. Current state: Right now, I feel pretty good. I can easily write this blog without feeling judgment, but I feel like I can be more expressive and concise about how I'm experiencing things. (Vague but with some direction).

3. Action plan: I plan to think about how to effectively communicate my thoughts and feelings briefly before I have a conversation with someone. (Not always possible, but the intention stands).

4. Action: I do the thinking before the talking.

5. Process: I do the thinking before talking on a consistent basis. (Not always, but ease into developing a habit to do so).

6. Feedback: I ask a friend or relative if I've been communicating more effectively lately.

7. I realize that I still have more work to do, but I now have a general idea of where I stand and what work I have left to do.

The system itself is pretty cut-and-dry, but the beauty of us as individuals is that no one system will work perfectly for everyone. This is meant to be a guideline for people to be able to think about this in a methodical way. It's meant for the more black-and-white thinkers and feelers among us to see that these technical methods can be applied to many uses.

Another beautiful thing about the closed-loop feedback system is that it's a loop. It keeps on going. We keep working for continuous improvement, and the system will always be applicable. The references may change, the way we get feedback may differ, and the process may become easier or even automatic over time, but the loop stays the same.

I once attended a lecture by a Microsoft executive who visited my university a few years back, and he said that "feedback is a gift". We should take feedback gratuitously, examine it, and work with it. We don't always get feedback in life, but I think it's good to try and seek it wherever we can, and especially if we know we will not like the result of the feedback. Honesty with ourselves is what really makes the feedback meaningful.

I hope you all learned something from this, I know I did!

Sources: Introduction to Control Systems, Prabir Barooah, Aug. 2016.