Motion control of the rabbit ankle joint with a flat interface nerve electrode

Area of Science:

• Biomedical Engineering
• Neuroprosthetics
• Motor Control

Background:

• Flat interface nerve electrodes (FINE) offer improved fascicular and subfascicular selectivity for nerve signal recording and stimulation.
• A novel control algorithm was developed to leverage the capabilities of FINE.
• The application of FINE and its control algorithm to animal models is a key area of research in neuroprosthetics.

Purpose of the Study:

• To evaluate a novel control algorithm for FINE in the context of motor control.
• To assess the feasibility of using FINE for precise motion control of a biological joint.
• To quantify the performance of the FINE control system in tracking dynamic ankle movements.

Main Methods:

• A 14-contact FINE was surgically implanted onto the sciatic nerve of rabbits (n=8).
• A real-time controller utilizing a multi-channel current stimulus isolator was implemented.
• Ankle joint motion was controlled to follow sinusoidal and filtered random trajectories.

Main Results:

• The system demonstrated good tracking performance for both sinusoidal (0.5 Hz, 1.0 Hz) and filtered random trajectories.
• Average root-mean-square (RMS) tracking error was consistently below 10%.
• The controlled ankle joint exhibited a motion range between -20.0° ± 9.3° and 18.1° ± 8.8°.

Conclusions:

• The developed control algorithm effectively enables multi-contact nerve electrode use for motion control.
• This technology shows promise for trajectory tracking control in musculoskeletal systems.
• The study validates the potential of FINE-based systems in restoring or augmenting motor function.