Innovative Design and Validation of an Ultrasound Examination Robot's End Effector with Passive Force Limitation Mechanism

In the field of medical automation, the safety of ultrasound examination robots is crucial for patient experience. Although traditional sensor-based force feedback systems are effective, they carry potential risks of failure. This study proposes an innovative passive maximum force-limited end effector (MFLEE), which relies on a physical mechanism instead of electronic sensing systems to limit force, thereby enhancing system reliability and safety. Initially, a detailed mechanical design was developed, incorporating a spring-ball limiting mechanism, and optimal parameters were selected based on theoretical analysis. Finite element analysis was then utilized to simulate the design, yielding force limits at various operational angles. In the experimental phase, actual measurements were compared with simulation results, confirming the efficacy of the MFLEE in practical applications. The results showed that the actual measured maximum force limit deviated by only 0.5N from theoretical predictions, indicating that the design could reliably control force output, offering a new safety assurance solution for ultrasound examination robots.