A New Trajectory-Generation Scheme for Overhead Cranes With High-Speed Load Hoisting

The objective of this study is to design a new anti-swing control scheme for overhead cranes, the performance of which equals or possibly surpasses the performance of a skilled crane operator. In this study, the anti-swing control problem is solved as a trajectory-tracking control problem. An anti-swing trajectory control scheme is designed based on the Lyapunov stability theorem, and then extended to an adaptive scheme to cope with parametric uncertainties, in which sufficient damping of load swing is achieved by modifying the reference trajectory of the trolley. The proposed control consists of a feed forward control and a non-linear PID control with gravity compensation, which guarantees asymptotic stability while keeping all internal signals bounded. The proposed control, allowing high-speed load hoisting, also guarantees accurate control of trolley position and rope length with optimum damping. In summary, the proposed control realizes a typical crane operation in practice, maintains its control performance in the presence of parametric uncertainties, and has a simple structure for easy implementation and gain tuning. The performance of the proposed control is shown with computer simulations.

This paper presents a novel method for adaptive anti-swing fuzzy logic control for overhead cranes with hoisting. The control action is distributed between three fuzzy logic controllers (FLC’s): trolley controller, hoist controller, and anti-swing controller. A method for varying the ranges of the variables of the three controllers as a function of the crane’s parameters and/or motion variables is presented. Simulation examples show that the proposed controller can successfully drive overhead cranes under various operating conditions.

Sensor is an indispensable component in feedback control. In anti-swing feedback control of automatic gantry crane system, sensors are normally employed to detect trolley position and payload swing angle. However, sensing the payload motion of a real gantry crane, in particular, is troublesome and often costly since there is hoisting mechanism on parallel flexible cable. Therefore, sensorless anti-swing control method for automatic gantry crane system is proposed in this study. The anti-swing control is performed in feedback control scheme without using real swing angle sensor. Instead, soft sensor approach is used to substitute the real swing angle sensor. The soft sensor is designed based on Dynamic Recurrent Neural Network (DRNN) as a state estimator. Thus, a DRNN is trained using input-output data to estimate payload swing angle from trolley acceleration and input voltage of trolley actuator. An experimental study using lab-scale automatic gantry crane is carried out to evaluate the effectiveness of the proposed sensorless anti-swing control. The results show that the proposed sensorless method is effective for payload swing suppression since similar performance to the sensor-based feedback anti-swing control is obtained.

One of the common industrial structures that are used widely in many harbors and factories and buildings is overhead crane. Overhead cranes are usually operated manually or by some conventional control methods. In this paper, we propose a hybrid controller includes both position regulation and anti-swing control. According to Takagi-Sugeno fuzzy model of an overhead crane, a fuzzy controller designed with parallel distributed compensation and Linear Quadratic Regulation. With the Takagi-Sugeno fuzzy modeling, the nonlinear system is approximated by the combination of several linear subsystems in the corresponding fuzzy state space region. Then by constructing a linear quadratic regulation subcontroller according to each linear subsystem, a parallel distributed fuzzy LQR controller is designed. Further, the stability of the overhead crane with the parallel distributed fuzzy LQR controller is discussed. Simulation results illustrated the validity of the proposed control algorithm and it is compared with a similar method parallel distributed fuzzy controller.

The trial stereovision is manufactured which is a non-contact sensor and tried to control the overhead crane by visual feedback. The stereovision has four degree of freedom for tracking and gazing with two cameras. The three-dimensional position of the crane load is provided with image data of two cameras, the focus distance, and four-vision drive angles and is used for crane control. The desired angles to control the stereovision is obtained using inverse kinematics that a point of intersection of two camera optical axes seems to always accord with the crane load center. On the other hand, in the overhead crane, positioning and vibration suppression of the crane load are controlled, using three-dimensional position of the crane load measured by the stereovision. The overhead crane load is transported by the simultaneous traveling, traversing and hoisting motions of the trolley and swings with the vibrating amplitude and its direction. Therefore the dynamic overhead crane model has five degree of freedom. Variable feedback digital gains of the trolley to control the crane load are pursued in consideration of the rope length change. Experimental results of the positioning and swing control of the crane load and tracking of the stereovision in case of the load transportation with up and down hoisting are reported, and the possibility of zoom lens activity is described. The experimental results of overhead crane control by visual feedback show that the control system was effective

The purpose of crane control is to transport the payload precisely to the desired destination while minimizing rope swing. Aiming at such an objective, this work thoroughly analyzes the dynamic system of the overhead crane with double-pendulum effects. The findings indicate that, despite being physically underactuated, the overhead crane can retain a fully actuated form mathematically. This form guides the natural transition of the controlled plant from the underactuated system to a fully actuated system (FAS). Within the FAS framework, the behaviors of both the original actuated and unactuated variables are interpreted as indirect outcomes of the control actions applied to the FAS. Consequently, the challenges of trolley positioning and swing elimination are reduced to control issues of FAS. Furthermore, a well-designed dynamical term is integrated into the system space of FAS to enhance swing suppression. The integration further leads to the control scheme for precise positioning and anti-swing, offering a fresh perspective on crane system control. Extensions to the cases with uncertainties and input saturation have also been discussed. Finally, we compare several representative methods for crane control and demonstrate that the proposed scheme outperforms them.

In this paper we propose a sliding-mode antiswing control for overhead cranes. The objective of this study is to realize an antiswing trajectory control with high-speed load hoisting. A sliding-mode antiswing trajectory control scheme is designed based on the Lyapunov stability theorem, where a sliding surface, coupling the trolley motion with load swing, is adopted for a direct damping control of load swing. The proposed control guarantees asymptotic stability while keeping all internal signals bounded. In association with a new antiswing motion planning scheme, the proposed control realizes a typical antiswing trajectory control in practice, allowing high-speed load-hoisting motion and sufficient damping of load swing. The proposed control is simple for a real-time implementation with high-frequency sampling. The effectiveness of the proposed control has been confirmed by experiments.

This paper solves the anti-swing control problem for a double-pendulum offshore boom crane suffering from persistent ship motion-induced disturbances. Most existing articles treat the hook-cable-cargo system as a single-pendulum system, however, when the hook mass can not be ignored or the cargo is large in size, the hook-cable-cargo system exhibits double-pendulum effect. In such case, the existing single-pendulum-based control approaches cannot achieve satisfactory performances. This paper proposes a partial feedback linearization control method for the anti-swing control of a double-pendulum offshore boom crane in the presence of ship roll and heave movements. Specially, by using the Lagrange's method, the dynamic model of a double-pendulum offshore crane is obtained. By inducing some elaborate variables, the original model is transformed into a more compact form. On the basis of the transformed model, a partial feedback linearization controller is designed and the stability is proven. Finally, simulation results are provided to verify the effectiveness of the proposed controller.

Generating a reference trajectory with defined kinematics for the IRb-6 manipulator

In this paper a controller is designed for the overhead cranes using the recently developed parallel differential (PD) eigenevalue assignment methodology. Using this theory, classical results for LTI control design carry over to the time-varying case. The main achievement of this paper is the first implementation of a controller designed using the PD eigenevalue theory in anti-swing control of overhead cranes, and the simulation results show the validity of this method.

An adaptive sliding mode control (ASMC) method with moving sliding surface (MSS) is proposed for anti-swing and positioning control of two-dimensional underactuated overhead crane in this paper. The designed moving sliding surface can change its slope in real time according to displacement error and speed error, thereby tracking performance of the trolley is improved. At the same time, a dynamic exponential term is added into the moving sliding surface so as to drive initial state variables into the sliding surface quickly to ensure the global robustness of the crane system. Finally, the controller switching gain is adjusted by an adaptive control law, which can effectively reduce chattering phenomenon occurring in the phase of sliding mode control. The controller can realize rapid positioning of the trolley and anti-swing control of the load under the condition of rope length changing. The global stability analysis of the suggested controller is given in the paper. The final simulation results confirm the effectiveness of the proposed controller.

An overhead crane is an underactuated system with less driving force than its degrees of freedom, which suffers from such factors as complex coupling between states, continuous disturbances, and so on. This paper designs an energy-based adaptive controller, which, together with a constructed fuzzy observer, makes an overhead crane stable at an “inclined” equilibrium point. Specifically, based on Lagrange's method, the traditional model for a crane is transformed into a novel dynamic equation expressed in new coordinates, based on which, uncertain disturbance within the system is then estimated by constructing a fuzzy observer, and an energy-based adaptive controller is subsequently designed to achieve satisfactory control performance. The closed-loop system is proven to be asymptotically stable by Lyapunov techniques and LaSalle's invariance theorem. Finally, some simulation results are included to show the advantages of the proposed control strategy.

As typical underactuated systems, overhead cranes are widely utilized in heavy-load transportation. However, their strong nonlinear coupling and underactuated characteristics complicate precise positioning and payload swing suppression. Furthermore, model uncertainties and external disturbances in practical environments increase control complexity and degrade system performance. To address these issues, this paper develops a trajectory tracking control scheme based on time delay estimation (TDE). Specifically, some transformations are made for the dynamic model and the TDE mechanism is used to estimate unknown nonlinear dynamics and external disturbances. Then, a sliding mode trajectory tracking controller, along with the TDE mechanism, is proposed for the trajectory tracking control and uncertainties estimation of the overhead crane system. Rigorous mathematical analysis is provided to demonstrate the asymptotic stability of the closed-loop system. Finally, simulation results verify the effectiveness of the proposed method in comparison with the existing control methods.

An overhead crane transfers the payloads of various volumes and weights depending on the each operation case. The friction factors characterized by damped coefficients can be changed in connection with operating environment. This study develops an adaptive version of sliding mode controller for the overhead cranes without priori information of system parameters composed of cargo mass and damped aspects. The proposed controller simultaneously executes five duties consisted of tracking the trolley and bridge, hoisting the cargo, keeping the payload swings small during the transport process, and absolutely suppressing the cargo vibrations at destination of trolley and bridge. Both simulation and experiment results indicate that the adaptive robust controller asymptotically stabilizes all crane system responses.

In actual overhead cranes, double-pendulum (DP) effect and uncertainty will inevitably occur. This study considers these effects to improve position tracking accuracy and sway regulation for perturbed DP overhead cranes. A prescribed-performance-control based sliding-mode control (SMC-PPC) scheme to regulate the sways and satisfy some transient and steady-state (TSS) performance metrics specifications on trolley tracking error. A prescribed performance function (PPF) and an error-transformation-function (ETF) are investigated so that performance metrics on trolley tracking error can be achieved. The challenge from the unavoidable friction is circumvented using a recently developed continuously differentiable friction model. The closed-loop stability is analysed using Lyapunov method. Simulation experiments show that both hook and payload TSS sways are effectively regulated and that trolley error converged into a pre-defined narrow vestigial set, having a rate of convergence of at least a preassigned value, exhibiting maximum overshoots and undershoots below some small enough pre-set values.KeywordsSliding mode controlPrescribed performance controlUnder-actuated systemsLyapunov method