How to Avoid a Multirotor Flight Crash under Complete Propeller Motor Failures Based on State Variable Approach

Abstract

In this paper, how to obtain motor speed signals for multirotor flight states to avoid a crash in the case of complete motor failures based on the Euler angle state variable approach is explained. First, the mathematical foundation for a multirotor as a rigid body is introduced. Secondly, state equations, maneuvers, and flight states (or flight operating points) of multirotors are summarized. Thirdly, in the case of complete motor failures, definitions of the motor speed control signal vector of the remaining motors and a method of directly providing motor speed control signals to achieve flight states to avoid a crash are provided. Finally, the method is applied to the problem of a multirotor vehicle experiencing motor failures. Numerical simulation results are also illustrated. In addition, the mathematical backgrounds of the Euler angle state equations of the multirotor and the proposed method are precisely explained in the appendices.

Conditionsto Realize Hexarotor Stable Flights to Avoid a Crash Under Complete Propellor Motor Failures

“…In this section, we summarize the mathematical foundation for describing the motion of a multirotor as a rigid body, and multirotor body frame configurations. We also describe dynamical Euler angle state equations of rotations, dynamical system state equations of translations, and the maneuvers and flight states (or operating points) based on [12]. Table 1:-Describes the symbols for the motion of a multirotor as a rigid body based [1].…”

“…Table 1:-Describes the symbols for the motion of a multirotor as a rigid body based [1]. Table 1:-Mathematical description for the motion of a multirotor as a rigid body [12]. [12].…”

“…Table 1:-Mathematical description for the motion of a multirotor as a rigid body [12]. [12]. In addition, linear operator is also described by a matrix form:-…”

“…However, there are the risks resulting in injury or deaths and damages if multirotors crash. Therefore, multirotor flight crash avoidances in the case of complete motor failures have been studied [2], [4]- [7], [11], [12], [14]- [16], [18]- [20]. However, feedback-loop controls to avoid a crash for both configurations, have been seldom studied.…”

“…They provided definitions of the operating points and equilibrium points of multirotors, and definitions of multirotor motor speed control signal vectors. Further they provided "add-on to underdetermined system equations" method of directly providing motor speed control signals for hexarotor or octorotor flights to avoid crashes (an open-loop control) when some motors fail and stop, and illustrated typical examples of hexarotor or octorotor flight states to avoid crashes obtained by the method [12]. Hence in this paper, to solve the problem to avoid a crash for the hexarotor in the case of complete failures, we expand on "add-on to underdetermined system equations" method based on [11], [12], [16], [18], and build a feedback-loop control to avoid a crash such that the hexarotor flight states to avoid crashes are stably realized when some motors fail and stop.…”