BiSTAC: A Class of Bipedal Soft Terrestrial-Aerial Bicopters

This letter presents the design, modeling, and motion control of BiSTAC, a novel hybrid terrestrial-aerial vehicle. BiSTAC features an innovative configuration that integrates a bicopter propeller system with a flexible bipedal locomotion mechanism, thereby enabling both bicopter flight and bipedal walking. Compared with other configurations of hybrid terrestrial-aerial vehicles, BiSTAC achieves functional reuse of its actuation system: the same set of actuators simultaneously supports both aerial flight and terrestrial walking, thereby improving the utilization efficiency of the locomotion mechanism while significantly simplifying the overall structural design. The dynamic model of BiSTAC is established, and both an aerial mode controller and a terrestrial controller are designed and implemented. Real-world experiments were conducted on the physical prototype, including flight performance experiments, terrestrial walking experiments, and bimodal locomotion experiments. The results are presented to validate the feasibility of the structural design of BiSTAC and demonstrate the effectiveness of the proposed controllers.