ResiRob | Stéphane Viollet

The objective of the ResiRob project (2025-2028) is to give these multimodal mobile robots new crucial capabilities in terms of resilience for evolutions in natural environments. Resilience is the capacity to withstand or to recover quickly from unexpected difficulties. When applied to mobile robotics, resilience can be seen as the ability of robots to absorb shocks when flying or rolling, to collide with obstacles without irreversible structural damages, or to be impacted by flying objects without crashing. Such physical survival is fundamental for robots whenever they operate into an unstructured environment, and the implications of a collision can be of high importance with for instance the inability to find survivors during a search and rescue mission, or financial repercussions with hardware destruction.

The heart of the ResiRob project is precisely to create new deformable robots that will not only absorb shocks but also sense collisions with appropriate proprioception to generate relevant trajectories, while offering multimodal locomotion capability.

Emblematic examples of resilient or multimodal robots and morphing structures. A) A multimodal mobility Morphobot [1]. B) Actuated expandable structure for a flying robot [14]. C) Impact resilient quadrotor [15] D) Crash resilient frame for a quadcopter [16]. E) Air ground robot SPIDAR [17]. F) Collision-resilient aerial robot with tensegrity structure [18]. G) Active joints applied to a deformable robot.

While morphing mechanisms have been investigated for unmanned aerial vehicles (UAVs), relatively little attention has been given to tricopters, despite their favorable efficiency and agility characteristics. We developed TriMorph, a transforming tricopter capable of continuously varying its frame through a single-actuator truss mechanism (Lee et al., 2026).

TriMorph expansion evolution.

In morphing drones, i.e., architectures capable of changing their configuration during flight, in addition to the tilt angle, the relative position of the propellers can also be modified in flight to adapt the drone’s capabilities to the mission requirements. We developed a geometric controller based on SE(3) that can be adapted to account for actuator saturations by prioritizing the position tracking with respect to attitude control (Stauder et al., 2026). This controller is also compatible with reconfigurable and morphing multirotors that can switch smoothly between under-actuation and full actuation.

Hexarotor with tilted propellers used to test our geometric controller.

References

2026