External control strategies for self-propelled particles: optimizing   navigational efficiency in the presence of limited resources
  We experimentally and numerically study the dependence of different navigation strategies regarding the effectivity of an active particle to reach a predefined target area. As the only control parameter, we vary the particle's propulsion velocity depending on its position and orientation relative to the target site. By introducing different figures of merit, e.g. the time to target or the total consumed propulsion energy, we are able to quantify and compare the efficiency of different strategies. Our results suggest, that each strategy to navigate towards a target, has its strengths and weaknesses and none of them outperforms the other in all regards. Accordingly, the choice of an ideal navigation strategy will strongly depend on the specific conditions and the figure of merit which should be optimized. 
Daniel F B Haeufle, Tobias B\"auerle, Jakob Steiner, Lena Bremicker,   Syn Schmitt, Clemens Bechinger
cond-mat.soft physics.bio-ph