This paper presents a novel approach for optical flow control of Micro Air Vehicles (MAVs). The task is challenging due to the nonlinearity of optical flow observables. Our proposed Incremental Nonlinear Dynamic Inversion (INDI) control scheme incorporates an efficient data-driven method to address the nonlinearity. It directly estimates the inverse of the time-varying control effectiveness in real-time, eliminating the need for the constant assumption and avoiding high computation in traditional INDI. This approach effectively handles fast-changing system dynamics commonly encountered in optical flow control, particularly height-dependent changes. We demonstrate the robustness and efficiency of the proposed control scheme in numerical simulations and also real-world flight tests: multiple landings of an MAV on a static and flat surface with various tracking setpoints, hovering and landings on moving and undulating surfaces. Despite being challenged with the presence of noisy optical flow estimates and the lateral and vertical movement of the landing surfaces, the MAV is able to successfully track or land on the surface with an exponential decay of both height and vertical velocity at almost the same time, as desired.

翻译：本文提出了一种用于微型飞行器（MAV）光流控制的新方法。由于光流观测量的非线性特性，该任务具有挑战性。我们提出的增量非线性动态逆（INDI）控制方案融合了一种高效的数据驱动方法来应对非线性问题。该方法能实时直接估计时变控制效率的逆，无需常数假设，同时避免了传统INDI中的高计算量。这一方法有效处理了光流控制中常见的快速变化系统动力学问题，尤其是高度依赖性的变化。我们在数值模拟和实际飞行测试中证明了所提控制方案的鲁棒性和高效性：包括在静态平坦表面上的多次着陆（涉及不同跟踪设定点），以及在移动和起伏表面上的悬停与着陆。尽管面临噪声光流估计以及着陆面横向与垂直运动的挑战，MAV仍能成功跟踪或着陆，且高度与垂直速度几乎同时呈指数衰减，达到预期效果。