Purpose

The purpose of this paper is to design an output-feedback algorithm based on low-power observer (LPO), robust chattering-free controller and nonlinear disturbance observer (DO) to achieve trajectory tracking of quadrotor in the Cartesian plane.

Design/methodology/approach

To achieve trajectory tracking control, firstly the decoupled rotational and translational model of quadrotor are modified by introducing backstepped state-space variables. In the second step, robust integral sliding mode control is designed based on the proportional-integral-derivative (PID) technique. In the third step, a DO is constructed. In next step, the measurable outputs, i.e. rotational and translational state variables, are used to design the LPO. Finally, in the control algorithm all state variables and its rates are replaced with its estimates obtained using the state-observer.

Findings

The finding includes output-feedback control (OFC) algorithm designed by using a LPO. A modified backstepping model for rotational and rotational systems is developed prior to the design of integral sliding mode control based on PID technique. Unlike traditional high-gain observers (HGO), this paper used the LPO for state estimation of quadrotor systems to solve the problem of peaking phenomenon in HGO. Furthermore, a nonlinear DO is designed such that it attenuates disturbance with unknown magnitude and frequency. Moreover, a chattering reduction criterion has been introduced to solve the inherited chattering issue of controllers based on sliding mode technique.

Practical implications

This paper presents input and output data-driven model-free control algorithm. That is, only input and output of the quadrotor model are required to achieve the trajectory tracking control. Therefore, for practical implementation, the number of on-board sensor is reduced.

Originality/value

Although extensive research has been done for designing OFC algorithms for quadrotor, LPO has never been implemented for the rotational and translational state estimations of quadrotor. Furthermore, the mathematical model of rotational and translational systems is modified by using backstepped variables followed by the controller designed using PID and integral sliding mode control technique. Moreover, a DO is developed for attenuation of disturbance with unknown bound, magnitude and frequency.

中文翻译：

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基于无模型低功耗观测器的未知扰动无人机四旋翼鲁棒轨迹跟踪控制

目的

本文的目的是设计一种基于低功耗观测器（LPO）、鲁棒无抖振控制器和非线性扰动观测器（DO）的输出反馈算法，实现四旋翼飞行器在笛卡尔平面上的轨迹跟踪。

设计/方法论/途径

为了实现轨迹跟踪控制，首先通过引入反步状态空间变量来修改四旋翼飞行器的解耦旋转和平移模型。第二步，基于比例积分微分（PID）技术设计鲁棒积分滑模控制。第三步，构建DO。下一步，可测量的输出，即旋转和平移状态变量，用于设计 LPO。最后，在控制算法中，所有状态变量及其速率都替换为使用状态观察器获得的估计值。

发现

该发现包括使用 LPO 设计的输出反馈控制 (OFC) 算法。在基于 PID 技术的积分滑模控制设计之前，开发了旋转和旋转系统的修正后推模型。与传统的高增益观测器（HGO）不同，本文利用LPO进行四旋翼系统的状态估计，解决了HGO中的峰值现象问题。此外，还设计了非线性 DO，可以衰减未知幅度和频率的干扰。此外，还引入了抖振减少准则来解决基于滑模技术的控制器继承的抖振问题。

实际影响

本文提出了输入和输出数据驱动的无模型控制算法。即只需要四旋翼飞行器模型的输入和输出即可实现轨迹跟踪控制。因此，在实际实施中，减少了板载传感器的数量。

原创性/价值

尽管针对四旋翼飞行器的 OFC 算法设计进行了广泛的研究，但 LPO 从未应用于四旋翼飞行器的旋转和平移状态估计。此外，通过使用反步变量修改旋转和平移系统的数学模型，然后使用PID和积分滑模控制技术设计控制器。此外，DO 是为了衰减未知边界、幅度和频率的干扰而开发的。