Implications of trajectory generation strategies for tubular continuum robots

Tubular continuum robots are particularly useful for minimally invasive surgery due to their small size and ability to dexterously manipulate in constrained environments. The robot can be used teleoperated or operated (semi-)autonomously. In both cases, safe manipulation has to be ensured considering constraints from the patient´s unique anatomy and pathology to prevent injury of nerves, vessels, and soft tissue. While probabilistic path planning methods have been proposed for tubular continuum robots which generate sequences of collision free configurations in obstructed environments, these methods do usually not explicitly consider different trajectory generations. In this paper, we evaluate four trajectory generation strategies in terms of the resulting Cartesian paths and spatial extent of the course of motion. We demonstrate the implication of the different strategies on both collision free path planning and an example medical scenario. In conclusion, consideration of trajectory generation strategies is indispensable, if the distance between intermediate configurations increases - even though those intermediate configurations might be collision free.