Studying Abstraction

Academic disciplines have become increasingly subdivided, developing ever more deeply within their respective fields. While specialization in each academic field is expected to become even more focused and advanced in the future, the problems of the world are, on the other hand, becoming more complex and multifaceted. For example, if we look at the response to the COVID-19 pandemic, it was necessary to solve the "medicine" × "economics" equation in a balanced way. I am sure you are all well aware that there are many problems that are difficult to solve with a single specialty alone, such as enhancing human support in our future super-aging society, or addressing global environmental and energy problems.

System Design Engineering is an academic field that seeks new solutions by combining and integrating various disciplines. In particular, the methodology of System Design Engineering is to find commonalities (analogies) between a target natural phenomenon and other phenomena, and to clarify the essence and principles that can explain them collectively.

Let me give a specific example. In the circuit equation for a voltage source, which you learn about in high school physics, the current is determined by resistance, capacitors, and inductance. In the equation of motion that describes the movement of an object, the velocity corresponding to an applied force is determined by viscous resistance, springs, and mass. Although these two phenomena differ, one being electrical and the other mechanical, they can actually be treated as systems with the same structure when viewed as such. You can also understand this from the fact that resonance in a circuit occurs from a combination of inductance and a capacitor, while in a mechanical system, vibration occurs from a combination of mass and a spring.

There is also an example from our laboratory's achievements that directly utilizes this. Suppressing vibrations in mechanical systems is a particularly important issue in the precision positioning of industrial robots and production systems. Such machines have resonant frequencies and can be modeled as a combination of a mass and a spring. When trying to move a machine at high speed to increase production efficiency, it is necessary to consider not only a single resonant frequency but also higher ones. While it is possible to consider higher-order resonances by connecting another pair of a mass and a spring, implementing control to stop the vibration was difficult because it required many differential operations. Based on a student's idea in our lab, we created a model with an infinite number of mass-spring combinations and found that it required no differential operations and could theoretically suppress an infinite number of resonances. This is called the wave equation, which describes many wave phenomena such as electromagnetic waves, sound, and fluids, and it is one of the problems that was solved through an abstracted perspective.

We have also applied this to attempts to reproduce human motion with robots. Reproducing human motion requires extracting information on both the velocity for moving through space and the force applied to an object, and then reproducing them with a robot. Velocity control and force control have opposing properties, a concept known as "duality." This is the same as the properties of a "voltage source" and a "current source" in an electrical circuit. The product of physical quantities with duality results in power (motive power, electric power), and their ratio becomes impedance. Furthermore, by focusing on acceleration, it becomes possible to integrate and reproduce both velocity and force simultaneously. We introduced this concept into the calligraphy robot shown in the figure and succeeded in reproducing the brushstrokes of a master calligrapher with the robot.

I hope this has conveyed how an approach of performing abstraction can lead to simple yet powerful solutions for challenges that have been considered difficult until now. This is the Susume for abstraction based on System Design Engineering. I look forward to seeing you all become the next generation of leaders who will pioneer a future society full of dreams, equipped with both deep expertise and a broad, bird's-eye perspective.