Control Allocation: Enhancing the Performance of Quadrotors High-Level Controllers
João C. Monteiro1; Fernando Lizarralde1; Liu Hsu1
1 Universidade Federal do Rio de Janeiro
Resumo
This paper studies four control allocations strategies with applications to quadrotor unmanned aerial vehicles (UAVs). Control allocation determines how a desired control effort is distributed among the available system inputs. When a system has more actuators than task degrees of freedom (DoF), this problem poses itself naturally, since there are multiple actuators choices capable of generating the same control effort. On the other hand, if the task DoF equals the number of actuators, unless some sort of saturation occurs, the mapping between control effort and actuators inputs is unique. This is exactly the case for quadrotor UAVs. To countermeasure this input saturation, four control allocation strategies are presented. The first is derived from the well known weighted least squares (WLS) criterion optimization. To obtain a more predictable control degradation, the direct control allocation (DCA) is introduced. Then, a generalization of the DCA, called partial control allocation (PCA) is studied. The last studied control allocation strategy is a suboptimal variation of the PCA (S-PCA). Simulations of the last three methods are conducted and their performance is compared.
Palavras-chave: control allocation; quadrotor; uav