Dart-Throwing Teaching Device Using Force Presentation Driven by Pneumatic Artificial Muscle

In this study, we developed a fingertip motion teaching suit using pneumatic artificial muscles (PAMs) to support the acquisition of optimal release timing in dart throwing. The proposed device is equipped with bidirectional bending-type PAMs placed near the metacarpophalangeal (MP) joint of the index finger and on the back of the hand. It provides haptic guidance for finger flexion and extension through the contractile force generated by pressurization. A control algorithm is proposed to pressurize the PAM at the pre- analyzed optimal release timing while accounting for actuator delay, so that the dart is released from the fingertip grip at the intended moment. By presenting the appropriate finger extension timing synchronized with the throwing motion, the system enables intuitive training and aims to improve dart- throwing skills. To validate the effectiveness of the device, dart- throwing experiments were conducted under three conditions— before, during, and after wearing the device—with healthy adult participants. The landing error and variability in release timing were evaluated. As a result, the release timing during device use became closer to the optimal reference timing compared to the pre-wear condition, and the average landing error also decreased. In the post-wear condition, the landing error was the smallest among the three conditions for three out of four participants, and the improvement in release timing was maintained at the same level as that observed during device use. These findings suggest the presence of a retention effect and indicate that the proposed PAM-actuated device can function as an effective feedback tool for teaching motor timing.