Environmental Interaction With Continuum Robots Exploiting Impact

Continuum robots offer unique potential benefits for environmental exploration, notably in using their maneuverability to navigate congested environments. However, significant challenges remain in environmental sensing using continuum structures, within which space for local sensing is often extremely limited. In this paper, we discuss the use of novel impulsive interaction using continuum robots to sense their environment. We introduce an impact model-based tapping approach with continuum robots which does not require the addition of specialized sensors, and demonstrate its utility in hardware. We contrast the impact model method to two alternative approaches to contact detection, “Finding Lost Wrenches” and the norm of the tendon length velocities. The methods are compared empirically on two different types of continuum robot hardware, a tendon actuated “Tendril” and the pneumatically actuated “OctArm”. The results identify relative strengths and weaknesses of the approaches. The statics-based “Finding Lost Wrenches” approach failed when the manipulators were in motion, and the length velocity norm method suffered in cases of reduced sensor resolution. The impact model approach is shown to include information not accessible to the other approaches.