Author: Yu Hang He, Email: hey6@unlv.nevada.edu
Date Last Modified: 07/09/2018

This week, members of the Hubo Lab invited me to a Korean BBQ restaurant. The occasion was planned for the celebration of three PHD candidates for successfully submitting their thesis papers. The entire Hubo Lab gathered together to celebrate the occasion. The lab members told me that the restaurant is very expensive and I noticed that each plate of beef cost around 10,000 to 15,000 won. Anyway, the meal was very delicious and I enjoyed the conversations with Lab members. I am very grateful for their hospitality once again.

In addition to the BBQ, I was invited to an Italian restaurant with Hubo Lab members. The restaurant is called Melting Table and it is owned by the family of Hyoubin, a Hubo lab member. The meal was delicious and a nice change of pace from all the Korean food I ate so far. I would recommend others to visit this restaurant if they have the chance to visit Daejeon.

This week, our Lab Manager, Dongbin, visited Leonard and me at KAIST. Dongbin introduced us to one of his underclassmen, who is currently working at Aerospace Engineering Lab at KAIST. He is currently working with the design of missiles. Dongbin and him shared many of their old story and memories with us.

This week, I learned more about the hierarchy in the Korean social system and the resulting difference between Korean and US customs surprised me. Anyone visiting Korea should understand the importance of social hierarchy. Age is one of the most important factor in determining this hierarchy. Basically, younger individuals should always show respect towards their seniors. That is extremely important in workplace. If someone does not greet their seniors properly, it would earn him an unfavorable reputation in the workplace. Following this hierarchy, table manners and customs are also very important. Thankfully, foreigners are excluded from this hierarchy, nevertheless, it is still important to consider this hierarchy so as not to accidentally offend others.

I learned that one of the biggest obstacle for my research process is my own stubbornness and inability to ask for help. One of the motto that I tried to guide myself is “work smarter not harder.” However, I found myself often struggling with a problem and refuse to ask others for help. My mindset becomes entrapped inside a loop that keeps repeating “I can do it” to myself. More often than not, I will later find out that the problem I am struggling with have a known solution and there are others who could have helped me. I hope I can change this bad habit of mine.

Last week, I captured myself performing some simple motions using Hubo Lab's Vicon motion capture system. Therefore, this week I focused my effort on trying to convert mocap data into Hubo 2 joint data.
I decided to write my program in Matlab first because it is easier to test and visualize the result of my program. Matlab allows me to use linear algebra and visualize my results in plot and graphs, which would require third party library to implement in C++.
The first step was to eliminate the difference between length of human arm and Hubo arm. I reduced the upper arm and forearm vectors in mocap data to unit vectors and multiply these vectors by the dimensions of Hubo arm. After plotting the data set, I noticed the noise and discontinuity in the data. I used filters to create a continuous slope and reduce the noise.

Currently, I am working with the inverse kinematic function to transfer the filtered mocap data into joint position data for Hubo 2. I am still in the process of modifying the IK function to accomplish my specific need. I am also considering filter the joint data instead of vector data.