Body rate decoupling using haltere mid-stroke measurements for inertial flight stabilization in Diptera

Abstract

Halteres, the modified rear wings of Diptera, have long been recognized as sensory organs necessary for basic flight stability. These organs, which act as vibrating structure gyroscopes, are known to sense strains proportional to Coriolis accelerations. While compensatory responses have been demonstrated that indicate the ability of insects to distinguish all components of the body rate vector, the specific mechanism by which the halteres are able to decouple the body rates has not been clearly understood. The research documented in this report describes a potential mechanism, using averaged strain and strain rate at the center of the haltere stroke, to decouple the inertial rate components. Through dynamic simulation of a nonlinear model of the haltere 3-dimensional trajectory, this straightforward method was demonstrated to provide an accurate means of generating signals that are proportional to three orthogonal body rate components. Errors associated with residual nonlinearity and rate-coupling were quantified for a bilaterally reconstructed body rate vector over a full range of pitch and yaw rates and two roll rate conditions. Models that are compatible with insect physiology are proposed for performing necessary signal averaging and bilateral processing.

Cross-modal influence of mechanosensory input on gaze responses to visual motion in Drosophila

“…These are reduced hindwings that oscillate in antiphase to the wings during flight (Deora et al, 2015;Pringle, 1948) and provide fast, phasic information (Fox and Daniel, 2008;Pringle, 1948) to both wing steering Dickinson, 1996, 1999) and gaze control (Hengstenberg, 1991;Huston and Krapp, 2009) motoneurons. Halteres experience small aerodynamic forces but large inertial forces, in particular a large inertial force associated with the haltere's oscillation and Coriolis forces associated with body rotations (Nalbach, 1993;Thompson et al, 2009). Although halteres function very differently from the vertebrate vestibular system, they perform some of the same functions, and are essential in maintaining flight stability in flies.…”

“…This gating mechanism suggests that some neck muscles will not contract without simultaneous visual and haltere input. Notably, this gating function is apparent when stimulating the haltere with a planar, two-dimensional oscillation, as would occur when the fly is flying straight with no body rotation (Nalbach, 1993;Thompson et al, 2009). Furthermore, visual stimuli can drive activity in the steering muscles of the halteres themselves, potentially changing the halteres' movements and thus, altering the mechanosensory stimulation from the haltere sensilla (Chan et al, 1998).…”

Haltere Mechanics and Mechanical Logic for Micro-Electro-Mechanical Systems (MEMS) Scale Bio-inspired Navigation Sensors

“…To a large extent, biological systems that utilize haltere input have been well studied, beginning with the work of Pringle (Frankel and Pringle, 1938). Within the scope of the DRI, we examined the biological system studies (Pringle, 1948;Thompson, 2009;Thompson et al, 2009;Motamed and Yan, 2005;Bender and Frye, 2009) and the developed engineering analogs, where appropriate. These engineering analogs focused on (1) control electronics for haltere sensors and (2) physics-based, engineering design models.…”

Status of the AFRL/RW Bio-Sensors Lab

“…True flies (Diptera) have halteres that provide gyroscope-type inputs through sensing Coriolis forces (Thompson et al, 2009); flying insects from other orders (non-Dipteran) in general do not. The number of lobula plate tangential cells that respond to optic flow patterns differ for different insects; they vary wildly even just among families of flies (Buschbeck and Strausfeld, 1997).…”

“…Acoustic signatures are also of interest for studying halteres, since the haltere oscillation frequency is the same as the wing beat frequency. (Dr. Tony Thompson's dissertation involved analytical studies of halteres, so measured haltere frequencies would be of interest for further analysis; Thompson, Wehling et al, 2009). A high school summer student (Josh Treloar) came our way in 2009, and we gave him a microphone and a laptop with Fourier transform routines on it, and had him measure acoustic signatures of flying insects.…”