Foldable Soft Leg-Assisted Wheel Robot.

Although mobile robots are expanding their capabilities to perform diverse missions for humankind, the functions of mobile robots are limited according to each type of locomotion. Hybrid mobile robots, which integrate the advantages of wheel and leg systems, emerge as a solution for robots to cross operating terrain. However, these systems also encounter inherent challenges, such as increased complexity and limited terrain adaptability. Herein, a foldable soft leg is proposed to assist the functionalities of a wheel mobile robot to traverse diverse terrain. The soft leg achieves high driving force and large deformability using the inherent compliance of foldable hinges by simple control of the motor-wire system. A hybrid mobile robot integrating the wheels and soft robotic legs is developed, exhibits posture adjustment abilities through the expansion and contraction of the legs. A novel hybrid locomotion mechanism is introduced, allowing the robot to traverse various harsh environments. Furthermore, additional equipment leveraging the unique characteristics of the soft robotic leg is also developed, enhancing the functionality of the hybrid mobile robot. This study provides valuable guidelines for the novel design of soft robotic legs to advance their potential for dexterous leg-wheel robots.