A small legged deformable robot with multi-mode motion

To realize walking and working in complex terrain or narrow space, a small legged robot with a mass of 5.6 g and a size of 70 mm x 60 mm x 30 mm is proposed. Piezoelectric and shape memory alloy actuators are combined for fast response and high flexibility. Six piezoelectric bimorphs serving as driving legs realize fast linear and turning motions in the forward and backward directions. Four shape memory alloy springs are excited for raising and dropping different legs to generate multiple motion modes. A dynamic model is built to guarantee the lifting motions of the designated legs. The experimental results show that it achieves linear moving and turning speeds as fast as 24.8 and 16.5 cm/s, respectively, whereas its startup time is only 0.1 s. Moreover, this robot lifts different legs up to 1 cm high with response time of 6, 8, and 6 s under the current of 1.5 A, respectively, which can recover to initial status. Hence, this robot is capable of fulfilling manipulation tasks, such as terrain detection, material transportation, obstacle crossing, and object capturing, thanks to the characteristics of small size, simple structure, good flexibility, and multi-functional locomotion.