The goal of our project is to develop an anthropomorphic robotic arm which closely mimics the functions and capabilities of an average human arm. Through literature reviews and results verification, we have found that LLDPE, UHMWPE, PET, and polycarbonate could be used as replacements for muscle, cartilage, ligament, and bone respectively.
Monday -Thursday , 10-12 and 1-3
- Dr. Benjamin — bbenjamin (at) bergen.edu
June, 15 2018
The most manageable means of powering the actuator was deemed to be electrothermal heating. Electrothermal heating is the conversion of electric energy to thermal energy for the purpose of producing heat. This is done by running an electric current through a resistor and that leads to the resistor heating up. a common example of a resistor is a copper wire.
After deciding on the heat source, it was time to work on fabricating the material. So, we started looking into means of applying the twist to the string. To do so, we decided to find an elevated platform on which we plan to attach an electric drill with a hook as the drill bit. Then, we would tie the ends of the fiber onto paper clips. one paper clip would be placed onto the hook, and the other would have a rotationally fixed weight placed on it.
We completed that setup and tested it by producing a sample twisted polyethylene fiber.
May, 27 2019
As stated last week, work on GUI has started. The process of placing and labeling the joints for the expected movement of the bones at joints was fairly complicated at first. Once a joint is a placed, the bones will be allowed to move in all three axes: x, y, and z. Now, the team had to figure out how to put limitations on the degrees of rotation or movement for each bone in the design. While placing the joints, the team learned that they must be placed inside one of the bones at the joints, for the bones to not overlap each other during the motion.
Alongside, more research on Linear Low-Density Polyethylene (LLDPE), the substance to be used in making the artificial muscle has been done over the week. This polymer has high elasticity and low water absorption. This substance can be easily stressed and will not break when heated as important for our project. To contract the artificial muscle fibers, required heat must be supplied. Through our research, we learned that LLDPE generates strain as high as 23% at 90° C.
Meanwhile, research on the heat source has just begun. Updates on the research will be provided in the next blog.
Furthering the research and starting to interface
June, 05 2018
Previously work uncovered the possibility of utilizing nylon as a synthetic muscle. However, the articles found suggested that the nylon may require temperatures exceeding 170 degrees Celsius to match the biological function that it would mimic. Thus, farther research was deemed necessary. This week, more in-depth research into polymer usage as artificial muscles was conducted. Polyethylene was the material of focus. An analysis suggests that Linear Low-Density Polyethylene, or LLDPE, may be a more efficient alternative to the nylon. It would require temperatures at a maximum of one hundred degrees Celsius to achieve results matching the biological functions. This difference is desirable because it will lead to lower energy requirements, and cause fewer issues for any complimentary material. Many other polyethylene compounds also require a lower temperature for similar performance than the nylon compounds. Thus, alongside the nylon, polyethylene will be tested.
Along with the research, work on the graphical user interface, or GUI (also used for general user interface), has started. The GUI was envisioned to be an anatomically accurate human arm that could be manipulated to manipulate the robotic arm. The first obstacle to overcome was finding a development software. It is unfortunate that no one on the team is proficient in any 3D modeling and animation software. Thus, research into possible software was required. After assessing numerous programs including unity, SolidWorks, and AutoDesk's fusion, AutoDesk's Maya was ultimately selected. Then, the process of learning the software and using it started. Fortunately, a usable skeleton model was found to provide a starting point for the GUI. The following image is the current state of the GUI.
To read more regarding the nylon and polyethylene synthetic muscles, view these links:
May, 29 2018
Since the aim of the project is to create a robotic arm with the same articulation and coordination as a human arm, it is extremely crucial for all of the team members to have an in-depth knowledge and understanding of the anatomy of a human arm. This week the team focused on expanding their knowledge of human arm structure and functions through intensive research. The skeleton of the human arm will be 3D printed in the upcoming weeks using PLA Filament. Simultaneously, some members looked into the subject of artificial muscles. Through his rigorous research, Patrick discovered a fairly new way of making artificial muscles using Nylon fibers as discovered by MIT Engineers.
To learn more, click the link below:
Next week, we'll continue with the research and hopefully start testing the nylon fibers. We also plan on searching about how to coil the fibers to make the muscles. Meanwhile, other members will start working on the Graphical User Interface (GUI). The idea is to use a 3D-modelling or animating software to create a human arm with all the bones and muscles to control the robotic arm.