Lift Force Control of Flapping-Wing Microrobots Using Adaptive Feedforward Schemes

This paper introduces a methodology for designing real-time controllers capable of enforcing desired trajectories on microrobotic insects in vertical flight and hovering. The main idea considered in this work is that altitude control can be translated into a problem of lift force control. Through analyses and experiments, we describe the proposed control strategy, which is fundamentally adaptive with some elements of model-based control. In order to test and explain the method for controller synthesis and tuning, a static single-wing flapping mechanism is employed in the collection of experimental data. The fundamental issues relating to the stability, performance, and stability robustness of the resulting controlled system are studied using the notion of an input-output linear time-invariant (LTI) equivalent system, which is a method for finding an internal model principle (IMP) based representation of the considered adaptive laws, using basic properties of the z-transform. Empirical results validate the suitability of the approach chosen for designing controllers and for analyzing their fundamental properties.