As a class of underactuated systems, cooperative dual rotary crane systems (DRCSs) are widely used to complete the task of large payload transportation in complex environments, since the working capacity of single cranes is quite limited. However, the control issues of DRCS fail to receive enough attention at present. Compared with single cranes, DRCSs contain more state variables, geometric constraints, and coupling relationships. Therefore, the complex kinematic and dynamic characteristics make controller design/stability analysis very challenging for DRCS. In order to solve these problems, based on the dynamic model of DRCS established by Lagrange’s method, an output feedback control method with consideration for actuator constraints is designed to realize accurate dual boom positioning and rapid elimination of payload swings. The stability of the equilibrium point for the closed-loop system is analyzed by using Lyapunov techniques and LaSalle’s invariance principle. To the best of our knowledge, this article yields the first solution for effective control of DRCS, which needs no velocity feedback, respects the actuator constraints, and is designed and analyzed without linearizing the complicated nonlinear dynamic equations. Finally, a series of hardware experiments on a self-built experimental platform is carried out to illustrate the effectiveness of the proposed controller. Note to Practitioners —This article is motivated by the control problem of dual rotary boom crane systems. In order to meet industrial requirements, the masses and volumes of to-be-hoisted cargoes are larger than before, and consequently, dual-crane systems are more frequently needed to fulfill transportation tasks. For such systems, although they improve the load capacity, greater challenges are caused when eliminating cargo swings in the transportation process. To the best of our knowledge, current control methods are mainly designed based on linearized/reduced models, whose performance may be not satisfactory when swing angles are large. Moreover, most methods use velocity signals with unexpected noises and ignore the constraints of actuators’ amplitudes, which may not be feasible in practical applications. To solve these problems, this article presents an output feedback controller, which can simultaneously solve the problems of saturation constraints and velocity signal unavailability. The proposed controller can guarantee accurate boom positioning and cargo swing elimination with guaranteed theoretical proof. Furthermore, the control performance is verified experimentally on a self-built testbed. In future efforts, we intend to apply the presented control method to industrial applications.

中文翻译：

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无速度反馈的复杂双回转起重机系统的非线性运动控制：设计，分析和硬件实验

作为一类欠驱动系统，协作式双旋转起重机系统（DRCS）被广泛用于完成复杂环境中的大型有效载荷运输任务，因为单起重机的工作能力非常有限。但是，DRCS的控制问题目前未能引起足够的重视。与单起重机相比，DRCS包含更多的状态变量，几何约束和耦合关系。因此，复杂的运动学和动态特性使控制器的设计/稳定性分析对于DRCS非常具有挑战性。为了解决这些问题，在基于拉格朗日方法建立的DRCS动力学模型的基础上，设计了一种考虑执行器约束的输出反馈控制方法，以实现精确的双动臂定位和快速消除有效载荷摆动。利用Lyapunov技术和LaSalle不变性原理分析了闭环系统平衡点的稳定性。据我们所知，本文得出了第一 有效控制DRCS的解决方案 没有 速度反馈，尊重执行机构的约束，并进行了设计和分析 没有线性化复杂的非线性动力学方程。最后，在自建实验平台上进行了一系列硬件实验，以说明所提出控制器的有效性。执业者注意 —本文受到双旋转动​​臂起重机系统控制问题的启发。为了满足工业需求，待吊装货物的质量和体积都比以前大，因此，更需要双吊车系统来完成运输任务。对于这样的系统，尽管它们提高了负载能力，但是在消除运输过程中的货物摆幅时会带来更大的挑战。据我们所知，当前的控制方法主要是基于线性化/简化模型设计的，当摆角较大时，其性能可能无法令人满意。此外，大多数方法使用带有意外噪声的速度信号，而忽略了执行器振幅的约束，这在实际应用中可能不可行。为了解决这些问题，本文提出了一种输出反馈控制器，它可以同时解决饱和约束和速度信号不可用的问题。所提出的控制器可以保证准确的动臂定位和消除货物摆动，并具有理论上的保证。此外，在自建测试台上通过实验验证了控制性能。在将来的努力中，我们打算将提出的控制方法应用于工业应用。