| Description |
The upper limb prosthetics field has advanced to where artificial hands can mimic human motions based on electrical signals emitted from muscular activation and can even open and close proportionate to the amplitude of signal they receive. However, these prostheses are very expensive, with some costing up to $75,000 USD. 3D-printing has greatly lowered the cost of manufacturing multiarticulate prosthetic hands, but there is currently no control system that can provide these inexpensive hands with proportionate, myoelectric control of more than one degree of freedom (DOF) at a similar price reduction. This project aimed to develop a low-cost control system that can interpret myoelectric data for multiple DOFs and control a prosthetic hand. The system was developed using a combination of inexpensive microcontrollers with advanced control algorithms. Once it was prototyped, we tested the system's signal acquisition capabilities against a research-grade system by comparing both systems' signal-to-noise ratios (SNR). We also investigated the capabilities of the low-cost system's proportionate control of multiple DOFs and compared this against the research-grade system, using root mean squared error (RMSE) as a metric. We found that the SNR of the low-cost system was statistically no worse than 44% of the SNR of a research-grade system. We also found that the RMSEs were typically a little better, and no more than 6% worse than the research-grade system's RMSEs. However, RMSEs were still high (therefore worse) due to a restriction of electrode channels used (six vs. typically greater than 32). Future work will focus on increasing the channels and therefore improving the control. With a materials cost of ~$675 USD, this prototype takes an important step towards providing high-end prosthetic technology at a relatively affordable cost. |
