Intermittent control strategy can enhance stabilization robustness in bumblebee hovering

Abstract

Active flight control plays a crucial role in stabilizing the body posture of insects to stay aloft under a complex natural environment. Insects can achieve a closed-loop flight control by integrating the external mechanical system and the internal working system through manipulating wing kinematics according to feedback information from multiple sensors. While studies of proportional derivative/proportional integral derivative-based algorithms are the main subject to explore the continuous flight control mechanisms associated with insect flights, it is normally observed that insects achieve an intermittent spike firing in steering muscles to manipulate wings in flight control discontinuously. Here we proposed a novel intermittent control strategy for a 3 degree of freedom (DoF) pitch-control and explored its stabilization robustness in bumblebee hovering. An integrated computational model was established and validated, which comprises an insect-inspired dynamic flight simulator and a novel discrete feedback controller as well as a simplified free-flight dynamic model. We found that the intermittent control model can achieve an angular-dominant flight control, whereas the continuous control model corresponds to an angular-velocity-dominant one. Given the biological constraints in sensorimotor neurobiology and musculoskeletal mechanics, the intermittent control strategy was examined capable of enhancing the stabilization robustness in terms of sensory latency, stroke derivation, spike interval, and damping strength. Our results indicate that the intermittent control strategy is likely a sophisticated flight control mechanism in insect flights while providing a bioinspired flight-control design for insect size flapping-wing micro air vehicles.

A six-degree-of-freedom proportional-derivative control strategy for bumblebee flight stabilization

“…Conventional studies (Ristroph et al 2010;Cheng et al 2011;Beatus et al 2015;Whitehead et al 2015) suggest that the proportional-derivative (PD) control strategy may be widely adopted by flying insects, where a proportional feedback is made for attitudes (roll, pitch and yaw) and positions (forward/backward, lateral and vertical) of insect body while a derivative feedback is for the time derivatives of their attitudes and positions. The flight control system of flying insects is observed to be inherently intermittent as recently pointed out by Xu et al (Xu et al 2020), however, a continuous PD controller can reasonably capture the behaviors in responds to perturbations (Ristroph et al 2010;Beatus et al 2015;Whitehead et al 2015) and the PD control strategy has been reported to work well for the flapping-wing flight control in insects (Yao et al 2020;Cai et al 2021).…”