The overseas YouTube channel Hacksmith Industries released a video on January 15, 2023 showing the production process of the six-legged riding robot “Megahex”. It claims to be the world’s largest riding six-legged robot. It was originally planned to be completed in about three months, but in the end it took a year and a half of repeated trial and error. The whole story of the long road is included in the video.
One of the members saw a Canadian Princess Auto excavator that can change direction using a bucket, and the idea of connecting six of them to create a spider-like riding robot started the project. I approached Princess Auto about the plan and was able to get an excavator and some money to spend in the store.
The original idea was to connect six excavators in a rectangle. It was to have six legs perform the same movement with different timings. However, the frame was changed to a hexagon because it became huge and lacked stability. Along with that, precision was required for assembly, and it became impossible to say that all leg movements were the same. Starting with this change, troubles occurred one after another, and the members repeated failures and trial and error.
In a test with four pilots who finally arrived, they succeeded in lifting the driver’s seat, but the behavior was unstable. It turned out that multiple pilots were out of sync and needed computer control. We built a complex system, including making a printed circuit board, went through countless troubleshooting, and integrated all the hardware and software. However, it didn’t work well at first.
After many trials and repeated measures, such as measures against heat generation of the motor and changes in the engine, we finally reached the walking test. However, it was difficult to adjust the balance between the legs that support its huge body and the legs that step forward. There was also a moment when the cylinder that held his parts together exploded. Still, little by little improvement is seen, and finally he succeeds in walking.
After that, while one person was riding and walking smoothly in the field, the frame broke and one leg came off the Megahex. Welding it up and moving it again resulted in the frame that the leg was attached to splitting in half, and the frame had to be completely rebuilt.
The members were wondering whether to make further repairs, but decided to end the challenge here because they had achieved their initial goal of successfully walking. The members say they put too much time, effort and money into this project and should not have done it.