An Arduino-controlled, robotic prosthetic arm designed to form certain finger grip patterns.
The primary objective of this project was to create a prosthetic forearm actuated by servos which resembled the anatomy of the human hand in terms of movements and grasping objects. The designing was done with the target to create a prosthetic which was capable of carrying out day-to-day activities with ease. This included tasks such as grabbing different shaped objects using a range of finger gripping patterns. Extensive literature review of leading prosthetic arm designs was carried out as well as open-source designs pushing the boundaries in the prosthetic design field. The design process was entirely carried out in SolidWorks. The designs were then 3D printed using readily available FDM 3D printers and assembled using typical machine tools.
The target of this prosthetic forearm design was to use the five individually actuated fingers to accomplish the following grip patterns.
Version 1.0 of this prototype utilises 5 servo motors to actutate the fingers. The forearm houses all the servos. Nylon wires act as tendons. The nylon wires are tied firmly to the servogear heads, and the rotation of the servos allowed the fingers to move. To find a detailed outline on how to assemble the nylon wires, check out the Assembly Guide pdf file. SolidWork and STL files are also available for download.
An external power supply of 6volts and 2.2A was used to power the servos. To find more information about the servo used in this project, click on this link: https://www.jaycar.com.au/servo-motor-standard-6-volt-with-metal-gear-13kg/p/YM2763
Follow the link below to check out the demo video of the prototype: https://youtu.be/SRb94xDs7CY
An alternate version of the prosthetic arm was designed utilising wood and aluminium rails. The design was impractical given that the prototype was too bulky and heavy for an amputee to use. Nonetheless, the aim of this prototype was to gain some woodworking and metalworking experience. Follow the link below to check out the demo video of this prototype: https://youtu.be/l63_LTtW4pg
There were several issues with version 1 of this robotic prosthetic arm. It is important to ensure there is sufficient tension in the nylon wires between the servo gearheads and the fingers. There were several instances where the nylon wires loosened up. As a result, certain finger grip patterns were unachieveable.
Version 1.0 was inspired by the open-source inMoov hand created by Langevin Gael (https://inmoov.fr/) and the open-source 3D-printed prosthetic arm created by Mahdi Design (check out his YouTube channel here: https://www.youtube.com/channel/UCGLXjNTLto9N5KgInF4aDbg)
Future versions of this robotic prosthetic arm are currently under works. The future version will aim to solve the tension and finger grip issues, as well as house all the servos and necessary electronics inside the forearm. Stay tuned for more updates.