In this article, a new control scheme is proposed to enable multiple quad-copters to cooperatively carry a cable-suspended payload. This cascaded controller takes into account the quad-copters underactuation and exploits the energetic passivity of the payload-cables-drones multibody system to achieve stable control. The controller is simple and requires no information about the cables tensions. A storage function inspired by the mechanical energy of the system is introduced and used to derive the control laws that achieve semiglobal exponential stability. The stability is shown to be robust with respect to bounded disturbance forces acting on the quad-copters and the payload. Additionally, a time-domain observer estimates the energy that perturbations may inject to the system and dissipates it through variable damping. This helps suppress disturbance-induced oscillations. The effectiveness of the control strategy is demonstrated in several experiments.

中文翻译：

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带有受干扰的电缆悬挂有效载荷的多直升机控制

在本文中，提出了一种新的控制方案，以使多个四轴直升机能够协同运载电缆悬挂的有效载荷。该级联控制器考虑了四旋翼飞机的欠驱动，并利用有效载荷-电缆-无人机多体系统的高能被动性来实现稳定控制。该控制器很简单，不需要有关电缆张力的信息。引入了受系统机械能启发的存储函数，并将其用于导出实现半全局指数稳定性的控制律。对于作用在四轴飞行器和有效载荷上的有界干扰力而言，显示出稳定性很强。另外，时域观察者估计扰动可能注入系统的能量，并通过可变阻尼来消散它。这有助于抑制干扰引起的振荡。在几个实验中证明了控制策略的有效性。