Fig. 1. Measurement of kinematics and forces. (A) 3D high speed videography. Three orthogonally aligned high speed cameras were used to film flies as they entered a small volume (wire-frame) next to a visual target (black cylinder). (B) Examples of frames recorded simultaneously by the three cameras. Body and wing kinematics were measured by matching markers for the head and abdomen, as well as the right (red) and left (yellow) wing in all three images. Arrows show the subsequently measured aerodynamic force projected back onto the images. (C) Wing position in body centered polar coordinates are defined by three angles: Stroke position (0° lateral, downstroke positive), stroke deviation (upward positive) and angle of attack (rotation around wing span, 0° leading edge up, positive rotation brings leading edge forward), following previously used conventions (Sane and Dickinson, 2001). (D) Dynamically scaled robotic wing. Each wing was controlled by three servo motors via coaxial drive shafts. Most of our data were acquired using a single-wing configuration. (E) Wing sensor and aerodynamic force. Forces were measured in a plane orthogonal to the wing span. For the analysis, the forces needed to be scaled and transformed into fixed frame coordinates, as shown in B. For further details on the setup refer to Materials and methods. A more detailed description of the robotic wing is given in Dickson and Dickinson (2004).