Many small ground vehicles that travel on sidewalks, such as electric wheelchairs, are equipped with a differential-wheeled mechanism to turn precisely on the spot and accurately control their trajectory. Conventional ground vehicles operating on public roads have action indicator devices such as blinkers and brake lights, which are effective in preventing collisions during operations. However, similar blinkers may not be suitable for sidewalk navigation because the differential-wheeled mechanism allows a neutral turn without considering the surroundings. In this study, we developed a new action-intention indicator for future differential-wheeled mobile robots that employs RGB light-emitting diode strip lights to express various colors and complex blinking patterns. Sensitivity evaluation experiments were conducted with approximately 50 subjects to determine the optimal colors and blinking patterns for a differential-wheeled mobile robot. Additionally, reaction-time acquisition experiments were conducted to confirm the effectiveness of the proposed intention-display device for mobile robots. Finally, we evaluated whether the determined blinking patterns exhibited appropriate power consumption.

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