Design and Bench Evaluation of a Sensor-Integrated Prosthetic-Leg Prototype

This study presents the design and preliminary bench evaluation of a sensor-integrated prosthetic-leg prototype. The platform combines a multi-material PAHT-CF/TPU 95A foot, articulated knee and ankle mechanisms, two surface electromyography channels, an MPU6050 inertial measurement unit, an Arduino Uno controller, and MG995 servomotors. EMG threshold crossings select discrete knee-servomotor commands, while an accelerometer-derived inclination estimate selects between two ankle-servomotor commands. The evaluation comprised exploratory finite-element analyses, separate static compression tests, and qualitative demonstrations of the sensor-to-actuator pathways. The foot model predicted a maximum displacement of 25.96 mm under 400 N, whereas a separate compression test recorded approximately 7 mm at 1000 N; these values do not constitute quantitative model validation because the loading, constraints, and displacement measures differed. The shank model produced a maximum equivalent stress of 23.89 MPa, and a separate shank-knee assembly test reached approximately 1.85 kN. The foot-ankle connection produced a stress estimate of 203.6 MPa against an assumed strength value of 60 MPa, identifying a critical design limitation. Functional observations demonstrated sensor-triggered command execution, but joint tracking accuracy, response time, actuator output under load, and control repeatability were not quantified. The prototype therefore provides an initial laboratory platform for investigating mechanical and sensing integration; structural redesign and quantitative bench testing are required before any load-bearing or clinical use can be considered.