Admissible thrust control laws for quadrotor position tracking

Abstract

In this paper a hierarchical position tracking controller for a quadrotor is presented, which consists of an inner attitude controller and an outer position controller. The tracking error dynamics form a nonautonomous cascade built up by a linear attitude error subsystem and a linear position error subsystem, coupled by a nonlinear interconnection term. The stability properties of the cascaded system essentially rely on the characteristics of the interconnection term, which strongly depends on the choice of the thrust. We characterize a class of admissible thrust control laws in terms of closed loop asymptotic stability and demonstrate the significant influence of different laws on the transient behavior of the system.

Trade-off between flight performance and energy consumption of a quadrotor

“…Let I be the inertial reference frame, B be the local reference frame, ⃗ d = X Y Z T be the vector of coordinates X, Y, Z ∈ R in I; ⃗ ρ = Φ Θ Ψ T be the vector of Euler angles Φ, Θ, Ψ ∈ R with respect to the North-East-Down frame (NED); ⃗ Ω = p q r T be the vector of the body roll, pitch and yaw rotational rates; and ⃗ τ = L M N T be the vector of moments L, M, N ∈ R around the roll, pitch and yaw axes. The attitude dynamics is presented in (1) [22], [23], where S (⃗ ρ) is defined as T(η) by Falconí et al [22]. The dynamics of the rotational rates are defined by Euler's equation [22], [23] in (2), where J ∈ R 3×3 is the inertia matrix of the quadrotor.…”

“…The attitude dynamics is presented in (1) [22], [23], where S (⃗ ρ) is defined as T(η) by Falconí et al [22]. The dynamics of the rotational rates are defined by Euler's equation [22], [23] in (2), where J ∈ R 3×3 is the inertia matrix of the quadrotor. The altitude dynamics is given by ( 3), where T is the total propulsive thrust, m is the quadrotor mass and g is the gravitational acceleration.…”

“…It's possible to write ω as a function of ω C by using (17), resulting in (22), which can be applied to (21) to obtain (23), where it becomes explicit that the altitude dynamics are affected by ξ.…”

Fault-tolerant position tracking of a hexacopter using an Extended State Observer

“…That is, for a commanded Ψ c , the roll command Φ c and the pitch command Θ c can be computed as [23] …”

“…The baseline controller is based on Nonlinear Dynamic Inversion for the output y = η (see e.g. [23], [24]). First, derive (4) once and insert (2)…”