Safe pre-operative traction applied and maintained to the fractured site in fracture reduction surgery is crucial. However, existing traction techniques performed by clinicians or manual traction devices are not elaborate and have no traction force information considering differences in patients’ bodies. The purpose of this study was to evaluate joint loads of fractured sites as pre-operative traction forces considering body mass index (BMI) during fracture reduction surgeries using a robotassisted device. We developed a lower-extremity dummy model to measure joint loads at hip, knee, ankle, and fractured sites. In 240 cases, four BMI types, six traction forces and two fractured sites were used. Results showed that joint load on major joints decreased as BMI increased. Additionally, joint load increased proportionally in the fractured tibia, but showed inverse tendency in the fractured femur. Control errors of up to 20% in repetitive control and approximately 30% in random control were measured, in comparison to estimated joint loads. Control error increased as traction force decreased. It is possible that applicability of robot systems to safe and precise surgical assistance can be validated. More precise traction control and real-time traction load monitoring technology will enable replacement of traction techniques in the near future.

In this study, we proposed a novel concept of electric sun visor comprising a dark, see-through sun shade material that ensures unimpaired driver’s vision with continuous control of the shade position. The shade extending from the windshield base along its surface may be subjected to severe vibration during driving unless the design parameters are carefully selected. A prototype was tested to collect acceleration data during driving. Based on the test data, an ADAMS dynamics model was validated. The mechanism of sun visor was optimized to minimize vibration based on the dynamics model, experimental design, and response surface method.