TEIKYO SDGs reportElucidate the “principle” of walking
- Hints for achieving the SDGs in the pursuit of principles -
Teikyo UniversityFaculty of Science and EngineeringDepartment of Mechanical and Precision Systems Associate ProfessorYoshito Ikemata
2006 Completed doctoral course at Nagoya Institute of Technology Graduate School. In Graduate School, he worked on research on passive walking robots. After graduating from Graduate School school, he became a specially appointed Assistant Professor at Nagoya Institute of Technology, and further focused on research on passive walking robots. In 2009, a passive walking robot developed by a team from the same university was certified as Guinness World Records™ for achieving continuous walking for over 13 hours. Since 2011, he has been working at the University of Tsukuba Graduate School. Since 2012, he has been assigned to the Faculty of Science and Technology, Teikyo Faculty of Science and Engineering.
To summarize this report ...
In order to achieve the SDGs, it is essential to pursue principles in all fields, and to advance various research and take action accordingly.
Research on passive walking robots started in Canada around 1980
It is a mechanism that walks only by the pendulum motion on the downhill without using power etc.
It is also attracting attention as a research that can move without using electricity etc.
Initially, the limit was a few steps, but a research team at Nagoya Institute of Technology succeeded in developing a robot that could walk tens of thousands of steps
The key was to keep the "stride" constant. Many approaches based on knowledge, experience, and techniques were used to arrive at the "principles" of passive walking.
Elucidation of the principles of passive walking may not only enable physical support, but also provide a basis for the evolution of existing techniques and ways of thinking. This will increase the possibility of achieving the SDGs
A meeting with a passive walking robot
When I was in the fourth year of undergraduate school and in the first half of Graduate School, my research subject was not robots. I was interested in engines and was involved in research on combustion and heat. However, the research team I belonged to at that time achieved certain results, so it was decided to disband. When I was thinking about going on to the second half of the Graduate School, I learned that the neighboring laboratory (the research team of Professor Hideo Fujimoto of Nagoya Institute of Technology) was conducting research on walking robots, which led me to get involved in this research. rice field. Passive walking is a walking system that converts the potential energy generated by gravity into kinetic energy. Currently, walking experiments on downhills = slopes are the mainstream. It is characterized by extremely high energy efficiency because it does not require any power such as electricity or a motor. The shape of the robot is similar to that of a human with only the bones below the waist. The way it walks with its knees bent is just like a human's movement, but it doesn't require programming.
Passive walking robots were originally created around 1990 by Dr. Tad McGear of Canada, who was an aeronautical engineering expert. Nowadays, you can watch Dr. McGear's research videos online, but when I saw the research videos at the time, I remember being fascinated by the extremely human-like movements. At that time, research into passive walking robots was still in its infancy, and they would collapse after taking just a few steps. Still, the impact it had on the world is immeasurable. Since then, research into passive walking robots has been gaining momentum around the world. Similarly, I was immersed in research to pursue the principle of bipedal locomotion.
think simple
Currently, the passive walking robot that we have developed can easily walk for several hours. The road to get here was extremely difficult. When I started my research, I couldn't walk at all, and my limit was a few steps. Since passive walking itself is a new field, research methods are also fumbling. We took photographs and videos of human walking, examined every mathematical model we thought was necessary, and researched papers from around the world. At the same time, I was also working on a passive walking simulation using a computer. There are two points that seem promising here. The first is to create an "equilibrium point". The equilibrium point (the cross-sectional point of the limit cycle) here is the movement that is repeated in a constant cycle, such as the heart and lungs. Walking is also a periodic movement that continues to put your feet out with a certain rhythm. The second point is that "stabilization" of the equilibrium point is important. Stabilization here means the property of returning to its original state even if it is disturbed by some external factors. For example, when a ball is rolled downhill, it accelerates, but in the case of humans, we control each step so that it does not accelerate so that it can walk at a constant speed. Now that the research path is clear, I don't know how to proceed. This painful stray state continued for several years.
It was the words written on the belt of a certain book that gave me a breakthrough notice. It is a phrase to the effect of "Don't think complicated, think simply". In fact, we were thinking a lot more complicated than that. Immediately, we reexamined the formulas and ideas, and carefully scraped away the elements that had become complicated. As a result of consolidating the issues into generating an equilibrium point and realizing stabilization, and simplifying the formula, we arrived at a single formula. At the same time, I realized that the important thing was setting the "stride length". Until then, there was no limit to the range in which the robot's legs could move, and the stride length was variable. Therefore, we installed a new synchronization mechanism on the left and right knees, and when we tried to make it walk with a constant stride length constraint, it was able to walk several tens or hundreds of steps. In this way, in 2005, I succeeded in deriving the principle of generating and stabilizing the equilibrium point.
Pursuit of principle
Dr. McGear, a pioneer, is also actively conducting analyzes using simple structures. This can be seen from the fact that the doctor created a spinning wheel-like structure that can roll down a slope at a constant speed. Although it has an extremely simple structure, the protruding part plays the role of a human foot, and the rolling force can be reset each time, so it can continue rolling at a constant speed. Analyzing with a primitive mechanism and consolidating ideas sometimes leads to the discovery of great value. Of course, the final robot mechanism is more complicated, but once we understand the principle, we can definitely move forward.
However, our goal is still far away. It is true that we succeeded in stabilizing a passive walking robot, but passive walking robots only function on slopes and do not walk well on horizontal surfaces. The principle of "human bipedalism" is a collection of complex elements. A passive walking robot with only a skeleton from the waist down is also a collection of theories and technologies such as the weight of the thigh, the arc shape of the legs, each joint, and the synchronization mechanism. There are many more elements such as It takes a tremendous amount of effort to validate all the elements. I'm also researching "running," hoping that it will provide hints for research on walking. I am steadily accumulating research, such as verifying using my own body, capturing videos of athletes running and analyzing their movements. However, recently there have been some promising results. I'm making a simple model to understand "running", and what a student worked on gave me a big hint. At first glance, it looks like an unbalanced structure with misaligned wheels that rattle, but when you actually move it, it's almost like running. With this, I feel that the path to reach the principle of running has come closer. The shortest route to research is to repeat thought, challenge, and analysis, which feels like a roundabout way.
Elucidation of Principles and Advancement of SDGs
Pursuing a principle also opens the door to the next principle. The same can be said for the SDGs. For example, climate change is assumed to be caused by a combination of complex principles, and in pursuit of the 108 indicators of the 17 goals, it is necessary to carefully clarify the principles one by one. If you can understand the principle, you will be able to embody the method for improvement, and you will be able to apply the materialized thing and start the next principle elucidation.
Our research has been applied to walking support for the elderly and people with disabilities, but there is also the possibility that it will lead to even greater uses than we could have imagined. In fact, I have experience involved in the development of walking support equipment, and it has been proven that it can reduce the burden of walking, but the process of learning the principles of walking itself has the potential to dramatically develop other academic fields and businesses. there is. My ultimate goal is to clarify the principle of walking. However, in order to understand it, we need the wisdom pioneered by our predecessors in the fields of physics and medicine, and the sophistication of the equipment used for simulations and analyses. Furthermore, materials and processing technology for constructing robots are required. In other words, increasing the speed of elucidation of the principle may lead to the development of science. There, we can envision a future similar to the achievement of a sustainable society aimed at by the SDGs. I believe that the data and knowledge accumulated in the process of pursuing principles can be a powerful step forward in advancing civilization.
