PMC8443146_01
Real-time control setup. (a) Tibialis anterior electrode placement. (b) Lateral gastrocnemius electrodes placement. Electrodes are placed in line with muscle bellies (location determined through palpation as amputee is asked to contract muscle). Cables are routed away from bony landmarks. (c) Real-time electromyographic (EMG) processing. EMG activity is collected and processed to generate smooth control signal proportionally modulating the magnitude of air pressure within pneumatic artificial muscles (PAMs). Contractile force from PAM generates change torque and stiffness at prosthetic ankle joint.
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F1
TA and residual lateral GAS muscle in real-time (dSPACE, CLP-1103, 0-10 V output) to create a smoothed control signal for each set of pressure valves (Figure 1). The setup then rectified the signal and applied a low-pass filter (2 Hz, second order Butterworth). The smoothed signal for each respective muscle was then sent to the pressure regulators, which generated pressure proportionally to the input voltage to actuate the device (Figure 1). Specifically, we placed EMG sensors (Neuroline 715, 1 mm height, Ballerup, Denmark) on residual lateral GAS and residual TA muscles (Figure 1).