Design and Feasibility Evaluation of a Low-Cost Wearable Tremor-Suppression Device Using IMU Sensing and PID-Controlled Actuation

Introduction: Hand tremors significantly affect the ability of individuals to perform essential daily activities independently. Existing clinical treatments, such as medications or surgical interventions, can be invasive, costly, or inaccessible in resource-limited settings. Consequently, there remains a pressing need for an affordable, non-invasive wearable assistive solution that provides active physical support.

Methods: This study presents the design and simulated feasibility evaluation of a low-cost wearable tremor-suppression prototype. The system utilizes an MPU9250 Inertial Measurement Unit (IMU) for continuous hand motion tracking and an ESP32 microcontroller for real-time signal processing. Employing frequency-based tremor detection, the system isolates tremor-like motion and utilizes a Proportional-Integral-Derivative (PID) control algorithm to drive a Brushless Direct Current (BLDC) motor coupled with an Electronic Speed Controller (ESC). The device was evaluated using simulated daily task scenarios—writing, drinking, eating, dynamic motion, and resting—to assess its stabilization capabilities.

Results: Performance was quantitatively assessed by measuring the Root Mean Square (RMS) angular displacement reduction. The active stabilization successfully reduced normalized RMS angular displacement by approximately 71–74% during the active simulated tasks (writing, drinking, eating, and dynamic hand motion). Furthermore, during the resting mode scenario, the device exhibited minimal unnecessary activation, demonstrating accurate state detection and appropriate response modulation.

Conclusions: The evaluation results demonstrate the preliminary engineering feasibility of the proposed prototype. The integration of off-the-shelf IMU sensing and BLDC motor actuation may effectively support the future development of affordable assistive technology for tremor management. However, as the current evaluation relied exclusively on simulated tremor profiles, formal clinical validation with real patients is needed to establish medical effectiveness.