Advancements in Spasticity Management: A Design Framework with PID Integration for Upper Limb Spasticity Training Device (ULSTraD)

The upper limb spasticity training device (ULSTraD) is a simulator designed to replicate various spasticity behaviors observed in patients with upper limb spasticity. Through a systematic development process involving requirements analysis, clinical data collection, conceptual design, prototyping, and integration of a Proportional-Integral-Derivative (PID) controller, the ULSTraD achieves precise control over servo motors. The PID controller, in conjunction with the PWM Controller PCA9885 and real-time feedback from the MPU6050 angle sensor, enables accurate spasticity behavior emulation. Optimal PID gains (Kp = 0.9, Ki = 1.0, and Kd = 0.00) were determined through tuning, resulting in the desired target position. By incorporating FSR 460 and conducting tests at various angles using the PID controller, ULSTraD displayed real-time responsiveness to external forces, enhancing its stability and accurately emulating upper limb spasticity behaviors. Guided by anthropometric measurements and clinical data, the ULSTraD closely resembles a real human arm affected by spasticity. The prototyping process involved 3D printing, welding, and assembly, leading to a functional prototype refined through iterative testing. To assess the similarity in range of motion (ROM) between ULSTraD and the human arm, a Paired Sample T-test was conducted, comparing the flexion and extension movements. The obtained p-value from the test was 0.9087, which indicates that there is no statistically significant difference in ROM between ULSTraD and the human arm during both flexion and extension movements. This validates ULSTraD's ability to replicate the human arm's range of motion affected by spasticity.