基于嵌套饱和方法的吊车系统非线性控制

针对吊车系统定位和防摆的控制要求,提出了一种基于嵌套饱和方法的非线性控制策略。对吊车系统动力学方程进行部分反馈线性化,并通过坐标变换将其转化为便于控制器设计的严格前馈级联规范型;在此基础上利用嵌套饱和非线性控制方法设计了吊车定位防摆控制器。仿真结果表明,该方法在较小的控制力作用下实现了吊车系统的定位和防摆,并且对于吊车系统参数的变化具有很强的鲁棒性。     

Two approaches for feedforward control and optimal design of underactuated multibody systems

An underactuated multibody system has less control inputs than degrees of freedom. For trajectory tracking, often a feedforward control is necessary. Two different approaches for feedforward control design are presented. The first approach is based on a coordinate transformation into the nonlinear input–output normal-form. The second approach uses servo-constraints and results in a set of differential algebraic equations. A comparison shows that both feedforward control designs have a similar structure. The analysis of the mechanical design of underactuated multibody systems might show that they are nonminimum phase, i.e., they have unstable internal dynamics. Then the feedforward control cannot be computed by time integration and output trajectory tracking becomes a very challenging task. Therefore, based on the two presented feedforward control design approaches, it is shown that through the use of an optimization procedure underactuated multibody systems can be designed in such a way that they are minimum phase. Thus, feedforward control design using the two approaches is significantly simplified.     

桥架起重机防晃控制非线性系统建模与研究

随着世界贸易的发展,桥架起重机发挥着越来越关键的作用;与此同时,桥架起重机防晃技术也日益受到关注。为分析桥架起重机系统的特性,为理论上验证与研究各种吊车控制方法的稳定性和效果提供参考,该模型在建立过程中考虑了电机对桥架起重机非线性系统的影响,对电机、小车和吊具与负载部分分别进行了分析、研究、建模与仿真,最终建立起桥架起重机防晃控制非线性系统完整的物理和数学模型,实现了对桥架起重机系统运动特性的完整描述。并用Matlab对电机、小车和吊具及负载部分,以及桥架起重机非线性系统的开环与闭环状态分别进行仿真,仿真结果验证了电机、小车、吊具及负载部分的特性,证明了模型的正确性,为研究桥架起重机防晃控制非线性系统提供了理论参考。     

三维桥式吊车自动控制实验系统

为分析桥式吊车系统的特性,验证各种吊车控制方法的稳定性并考察其实际控制效果,根据桥式吊车的工作原理与组成结构,设计并搭建了一个三维桥式吊车实验系统.该系统主要由机械主体、驱动装置、测量装置和控制系统四部分组成,能够较为真实地反映实际吊车系统的动态特性和运行过程:其中的控制器部分基于Matlah/Simulink平台,可...     

Motion planning for three-dimensional overhead cranes with high-speed load hoisting

This paper proposes a systematic anti-swing motion-planning method for three-dimensional overhead cranes, based on the load-swing dynamics of a two-dimensional overhead crane. First, a model-following anti-swing control law is designed based on the load-swing dynamics of a two-dimensional overhead crane, where the Lyapunov stability theorem is used as a mathematical tool. Then a new anti-swing motion-planning scheme is designed for a two-dimensional overhead crane based on the model-following anti-swing control law and typical crane operation in practice. Finally, the new anti-swing motion-planning scheme is extended for a three-dimensional overhead crane, based on the geometric relationship between a three-dimensional overhead crane and its two-dimensional counterpart. As a result, the proposed method avoids solving the load-swing dynamics of a three-dimensional overhead crane which is much more complicated than that of its two-dimensional counterpart. Furthermore, the proposed method can be applied to any existing overhead cranes without increasing their actuator torque capacity. The effectiveness of the proposed method is demonstrated by generating high-performance anti-swing trajectories with high-speed long-distance load hoisting.     

Dynamics analysis and fuzzy anti-swing control design of overhead crane system based on Riccati discrete time transfer matrix method

This paper describes an efficient method called Riccati discrete time transfer matrix method of multibody system (MS-RDTTMM) for studying the dynamic modeling and anti-swing control design of a two-dimensional overhead crane system, which consists of a trolley, rope, load, and control subsystem. Regarding the rope as a series of rigid segments connected by hinges, a multibody model of the overhead crane system can be developed easily by using MS-RDTTMM. Then three separate fuzzy logic controllers are designed for positioning and anti-swing control. For improving the performance of the predesigned fuzzy control system, the genetic algorithm based on MS-RDTTMM is presented offline to tune the initial control parameters. Using the recursive transfer formula to describe the system dynamics, instead of the global dynamics equation in ordinary dynamics methods, the matrices involved in this method are always very small, and the computational cost of the dynamic analysis and control system optimization can be greatly reduced. The numerical verification is carried out to show the computational efficiency, numerical stability, and control performance of the proposed method.     

采用神经网络的双吊车自适应防摆控制

由于工业实践对运输能力提出了更高的要求,双吊车的应用日益广泛.然而其动力学模型非线性很强,因此控制器结构十分复杂.另一方面,大型货物的摆动很难抑制,这给双吊车的自动化带来了巨大的挑战.为了处理以上问题,首先,采用神经网络准确地估计了系统的模型,在此基础上提出了一种自适应防摆控制方法,很好地实现了双吊车系统的防摆控制;然后,采用李雅普诺夫方法,严格地证明了系统在平衡点的渐近稳定性;最后,通过大量的实验结果,验证了该方法具有良好的性能.     

一类欠驱动机械系统的非线性控制

针对一类欠驱动机械系统．分析了其数学模型,提出了一种基于部分反馈线性化的非线性控制方案．该方案利用精确线性化的方法将欠驱动系统直接激励部分线性化,将被动部分作为系统的内部动态考虑;并选择直接激励的自由度作为系统输出．进行系统的轨迹跟踪控制;通过分析系统的内部动态,证明了零动态的稳定性能保证控制系统的稳定性．最后通过对吊车的负载防摆控制的研究．验证了该方案的可行性．     

Adaptive Proportional-Derivative Sliding Mode Control Law With Improved Transient Performance for Underactuated Overhead Crane Systems

In this paper, an adaptive proportional-derivative sliding mode control (APD-SMC) law, is proposed for 2D underactuated overhead crane systems. The proposed controller has the advantages of simple structure, easy to implement of PD control, strong robustness of SMC with respect to external disturbances and uncertain system parameters, and adaptation for unknown system dynamics associated with the feedforward parts. In the proposed APD-SMC law, the PD control part is used to stabilize the controlled system, the SMC part is used to compensate the external disturbances and system uncertainties, and the adaptive control part is utilized to estimate the unknown system parameters. The coupling behavior between the trolley movement and the payload swing is enhanced and, therefore, the transient performance of the proposed controller is improved. The Lyapunov techniques and the LaSalle's invariance theorem are employed in to support the theoretical derivations. Experimental results are provided to validate the superior performance of the proposed control law.      

桥式吊车系统的伪谱最优控制设计

对于桥式吊车系统的最优控制问题,根据实际的工况要求,性能指标有时不一定是标准的二次形式.同时,在实际的控制问题中,状态和控制输入往往会受到一些边界条件和路径过程中的约束.针对这一问题,本文应用Chebyshev伪谱优化算法来处理,它可以处理状态和控制约束的非线性最优化问题以及一个非标准的目标函数.首先对桥式吊车系统模型进行一系列的坐标变换,将其转变为上三角系统形式的误差模型.然后将桥式吊车最优控制问题转化成具有一系列代数约束的参数优化问题,即非线性规划问题.通过求解离散化后的参数优化问题,得到桥式吊车的最优控制律.本文还给出了Chebyshev伪谱最优解的可行性和一致性分析.最后,在仿真研究中验证该控制器的有效性.     

An Energy-based Nonlinear Coupling Control for Offshore Ship-mounted Cranes

This paper proposes a novel nonlinear energy-based coupling control for an underactuated offshore ship-mounted crane, which guarantees both precise trolley positioning and payload swing suppressing performances under external sea wave disturbance. In addition to having such typical nonlinear underactuated property, as it is well known, an offshore ship-mounted crane also suffers from much unexpected persistent disturbances induced by sea waves or currents, which, essentially different from an overhead crane fixed on land, cause much difficulty in modeling and controller design. Inspired by the desire to achieve appropriate control performance against those challenging factors, in this paper, through carefully analyzing the inherent mechanism of the nonlinear dynamics, we first construct a new composite signal to enhance the coupling behavior of the trolley motion as well as the payload swing in the presence of ship′s roll motion disturbance. Based on which, an energy-based coupling control law is presented to achieve asymptotic stability of the crane control system′s equilibrium point. Without any linearization of the complex nonlinear dynamics, unlike traditional feedback controllers, the proposed control law takes a much simpler structure independent of the system parameters. To support the theoretical derivations and to further verify the actual control performance, Lyapunov-based mathematical analysis as well as numerical simulation/experimental results are carried out, which clarify the feasibility and superior performance of the proposed method over complicated disturbances.     

Novel Approach for Adaptive Tracking Control of a 3-D Overhead Crane System

Traditionally, overhead crane systems are operated by humans. However, automatic operation would reduce both the risk and the personnel costs. From the engineering viewpoint, the most important issues in crane motion are high positioning accuracy, short transportation time, small sway angle, and high safety. Hence, stabilization control is particularly concerned. In this paper, a novel adaptive control scheme including both the cart motion dynamics and the swing angle dynamics is designed to ensure the stability of the closed-loop system. No system parameters are needed, and accurate position tracking as well as minimal swing is achieved. The stability of the closed-loop system is proved via Lyapunov theory. Simulation studies and experiments are performed to demonstrate the validity of the proposed control scheme.     

基于能量守恒的桥式吊车参数辨识研究

针对实际桥式吊车系统物理参数不易获得的问题,提出一种基于能量守恒的参数辨识方法。该方法根据能量守恒原理建立辨识回归方程,然后用非负最小二乘法处理辨识实验数据,得到桥式吊车的控制器设计模型。以桥式吊车实验系统为背景,模拟桥式吊车的实际运行特点,进行辨识实验,获得系统的数学模型。在此基础上用LQＲ 控制器验证了该方法在桥式吊车实验系统上辨识结果的准确性,证明该辨识方法对桥式吊车的控制有很大帮助。     

An Enhanced Coupling Nonlinear Tracking Controller for Underactuated 3D Overhead Crane Systems

An enhanced coupling nonlinear tracking control method for an underactuated 3D overhead crane systems is set forth in the present paper. The proposed tracking controller guarantees a smooth start for the trolley and solves the problem of the payload swing angle amplitude increasing as the transferring distance gets longer for the regulation control methods. Different from existing tracking control methods, the presented control approach has an improved transient performance. More specifically, by taking the operation experience, mathematical analysis of the overhead crane system, physical constraints, and operational efficiency into consideration, we first select two desired trajectories for the trolley. Then, a new storage function is constructed by the introduction of two new composite signals, which increases the coupling behaviour between the trolley movement and payload swing. Next, a novel tracking control strategy is designed according to the derivation form of the aforementioned storage function. Lyapunov techniques and Barbalat's Lemma are used to demonstrate the stability of the closed‐loop system without any approximation manipulations to the original nonlinear dynamics. Finally, some simulation and experiments are used to demonstrate the superior transient performance and strong robustness with respect to different cable lengths, payload masses, destinations, and external disturbances of the enhanced coupling nonlinear tracking control scheme.     

A new design approach for the anti-swing trajectory control of overhead cranes with high-speed hoisting

This paper proposes a new approach for the design of anti-swing control of overhead cranes. An anti-swing trajectory control scheme is designed based on the trolley and load-hoisting dynamics, and then extended to an adaptive scheme. The load-swing dynamics is controlled by employing a sliding surface that couples the load-swing dynamics with trolley motion. The number of degrees of freedom of the trolley and load-hoisting dynamics is the same as that of the control inputs; therefore, the control problem is reduced to finding a coupled sliding surface that stabilizes the crane control system, based on the load-swing dynamics. In this study, the Lyapunov stability theorem is used as a mathematical design tool. The proposed control guarantees asymptotic stability of the anti-swing trajectory control while keeping all internal signals bounded. The coupled sliding surface allows a direct control of the damping of load swing. In addition, the proposed control provides clear gain-tuning criteria for easy application. Finally, the proposed control realizes an anti-swing control along a typical anti-swing trajectory in practice, with high-speed load hoisting. The validity of the theoretical results is shown by computer simulation.     

二维桥式起重机的滑模控制

基于滑模控制理论,研究二维桥式起重机的控制器设计问题.首先,考虑小车端受到外界干扰的情况以及利用一些等价变换,得到一个四阶桥式起重机动力学模型;然后,根据得到的动力学方程,分别设计一种比例微分滑模控制器和一种比例微分积分滑模控制器,进而通过构造李雅普诺夫函数的方法证明两种控制器下滑模面的可达性和系统的稳定性;最后,设计1组对比仿真实验和1组在自制的桥式起重机实验平台上的验证性实验.实验结果表明,所设计的两种滑模控制器均可以使桥式起重机达到给定的控制目标.     

Adaptive inverse control of linear and nonlinear systems using dynamic neural networks

In this paper, we see adaptive control as a three-part adaptive-filtering problem. First, the dynamical system we wish to control is modeled using adaptive system-identification techniques. Second, the dynamic response of the system is controlled using an adaptive feedforward controller. No direct feedback is used, except that the system output is monitored and used by an adaptive algorithm to adjust the parameters of the controller. Third, disturbance canceling is performed using an additional adaptive filter. The canceler does not affect system dynamics, but feeds back plant disturbance in a way that minimizes output disturbance power. The techniques work to control minimum-phase or nonminimum-phase, linear or nonlinear, single-input-single-output (SISO) or multiple-input-multiple-ouput (MIMO), stable or stabilized systems. Constraints may additionally be placed on control effort for a practical implementation. Simulation examples are presented to demonstrate that the proposed methods work very well.     

Linear dynamics of flexible multibody systems

We consider mechanical systems where the dynamics are partially constrained to prescribed trajectories. An example for such a system is a building crane with a load and the requirement that the load moves on a certain path.Enforcing this condition directly in form of a servo constraint leads to differential-algebraic equations (DAEs) of arbitrarily high index. Typically, the model equations are of index 5, which already poses high regularity conditions. If we relax the servo constraints and consider the system from an optimal control point of view, the strong regularity conditions vanish, and the solution can be obtained by standard techniques.By means of the well-known \(n\)-car example and an overhead crane, the theoretical and expected numerical difficulties of the direct DAE and the alternative modeling approach are illustrated. We show how the formulation of the problem in an optimal control context works and address the solvability of the optimal control system. We discuss that the problematic DAE behavior is still inherent in the optimal control system and show how its evidences depend on the regularization parameters of the optimization.     

基于输入整形技术的吊车系统防摆控制

针对传统吊车防摆闭环控制方法存在的控制器设计相对复杂、控制效果不理想、不易实现等问题,提出了一种基于经典控制理论与前馈输入整形技术相结合的控制技术。首先,对吊车系统进行建模并简化数学模型,采用经典控制理论设计吊车的伺服控制系统。其次,在吊车伺服系统的基础上,引入输入整形技术设计吊车系统的ZV输入整形器。最后,通过MATLAB仿真验证所提出控制技术的有效性。