Crane Control Research Articles

A model to control self-erecting tower cranes with elastic structure

Control of large-scale tower cranes is still an open research field. Due to their lightweight structure and their large geometry structural deformations occur and need to be considered for anti-sway feedback control. especially, for self-erecting tower cranes no proper model has been published yet. In this paper, a flexible multi-body model for this type of crane is derived and a modal analysis is performed. The results are compared to measurement data of an industrial tower crane.

Modeling and discrepancy based control of underactuated large gantry cranes

An important structural dynamics problem of the large gantry cranes are horizontal elastic oscillations mainly excited by the trolley motion. They reduce the crane operation performance and lead to faster material wear of the crane construction. In this article a distributed parameter model of large gantry cranes applying Hamilton’s principle is presented. In order to stabilize the system dynamics the use of a generalized error measure, called discrepancy, is proposed. Applying the associated stability theory, i.e. stability with respect to two discrepancies, a nonlinear stabilizing control for the underactuated gantry crane is derived. The proposed control strategy has been verified by simulations.

Vibration control of stacker cranes utilizing dynamic interaction between motion and vibration

Vibration control of stacker cranes utilizing dynamic interaction between motion and vibration

Vision-based control of a knuckle boom crane with online cable length estimation

A vision-based controller for a knuckle boom crane is presented. The controller is used to control the motion of the crane tip, and at the same time, compensate for payload oscillations. The oscillations of the payload are measured with three cameras that are fixed to the crane king, and are used to track two spherical markers fixed to the payload cable. Based on color and size information, each camera identifies the image points corresponding to the markers. The payload angles are then determined using linear triangulation of the image points. An extended Kalman filter is used for the estimation of payload angles and angular velocity. The length of the payload cable is also estimated using the least-squares technique with projection. The crane is controlled by a linear cascade controller where the inner control loop is designed to damp out the pendulum oscillation, and the crane tip is controlled by the outer loop. The control variable of the controller is the commanded crane tip acceleration, which is converted to a velocity command using a velocity loop. The performance of the control system is studied experimentally using a scaled laboratory version of a knuckle boom crane.

Anti-swing strategy of overhead cranes based on prescribed performance PID control

How to ensure anti-swing and adaptive control for cranes when used in complex outdoor environment such as docks is a difficult problem. Although the traditional PID control can solve the problem of robust adaptive and disturbance rejection very well, the quality of PID parameters depends too much on the experience of adjusting parameters or requires a lot of trial and error, so a new non-linear PID control method is proposed in this paper. The theory of prescribed performance control is introduced, and a non-linear closed-loop PID controller is designed based on the idea of performance function and error conversion of prescribed performance control. As the parameter adjustment is more flexible, the system has better robustness, adaptability and immunity to disturbance. Experiment results show that using the designed anti-swing strategy can effectively realise the anti-swing and it has excellent anti-interference ability.

Anti-swing strategy of overhead cranes based on prescribed performance PID control

How to ensure anti-swing and adaptive control for cranes when used in complex outdoor environment such as docks is a difficult problem. Although the traditional PID control can solve the problem of robust adaptive and disturbance rejection very well, the quality of PID parameters depends too much on the experience of adjusting parameters or requires a lot of trial and error, so a new non-linear PID control method is proposed in this paper. The theory of prescribed performance control is introduced, and a non-linear closed-loop PID controller is designed based on the idea of performance function and error conversion of prescribed performance control. As the parameter adjustment is more flexible, the system has better robustness, adaptability and immunity to disturbance. Experiment results show that using the designed anti-swing strategy can effectively realise the anti-swing and it has excellent anti-interference ability.

Optimization of fuzzy logic controller parameters using modern meta-heuristic algorithm for gantry crane system (GCS)

Robust control of underactuated nonlinear systems is a challenging task using conventional methods because of uncertainties which may lead to failure especially for mechanical and robotic applications. Fuzzy logic controller (FLC) is one of the methods specifically used for designing a robust controller that is able to deal with nonlinearity and achieve satisfactory performance for control applications. FLC uses heuristic information or expert operator knowledge to create its mechanism. However, nonlinearities exist in the control systems make its rule-based FLC design a non-trivial task. Manual trial and error tuning method is common way used for tuning the parameters of FLC to achieve the desired performance of the system. Hence, an automatic tuning using optimization algorithm is necessary. Meta-heuristic optimization algorithms are applied to tune the parameters of FLC automatically. In this paper, three popular meta-heuristic algorithms are used to optimize the scaling factors of FLC, i.e. Particle Swarm Optimization (PSO), Cuckoo Search (CS) and Differential Evolution (DE) to improve the effectiveness of FLC design. A gantry crane system, which is a nonlinear system, is used as test system for this project. The simulation of the optimization of FLC parameters by using meta-heuristics algorithms was successfully achieved. The simulation results show that the optimization techniques for FLC are effective to improve the performance of conventional FLC for gantry crane control, i.e. position control and anti-swing control. In addition, PSO performs better than CS and DE in optimization of FLC for gantry crane system.

Application of Analogue Derivators for Obtaining Direct Non-Measurable Components of the State Vector in Crane Control

Abstract This paper presents a simple-to-use system for estimating non-measurable components of crane state vector considering parameter changes. To obtain them, it is possible to use a numerical derivative, where the measurement noise causes great inaccuracies, or the Luenberger observer and Kalman filter, which require knowledge of the dynamics of the controlled system, which is constantly changing with the crane.

Nonlinear Stable Transportation Control for Double-Pendulum Shipboard Cranes With Ship-Motion-Induced Disturbances

From the practical perspective, with large-scale cargoes or nonnegligible hook masses, the centers of gravity of cargoes and hooks do not coincide with each other, and shipboard cranes usually exhibit complex double-pendulum effects during ship-to-ship or ship-to-harbor transportation, which dramatically increase the complexity of dynamic characteristics and make the control issue very challenging. At present, there is no reported work on control of double-pendulum shipboard cranes yet. To tackle such problems, this paper obtains the dynamic model of double-pendulum shipboard cranes and then provides an effective nonlinear antiswing feedback controller to achieve stable cargo transportation. Specifically, new state variable signals are generated by combining the original state variables with the ship motion (induced by sea wave perturbations). Based on this, by adding some elaborately designed nonlinear terms, an antiswing feedback controller is proposed, which can achieve stable transportation with suppressed swing, and the closed-loop asymptotic stability is proven without any linearizations or approximations to the original complex nonlinear dynamics, with rigorous theoretical analysis. As far as we know, the paper provides the first solution for both controller design and stability analysis of double-pendulum shipboard cranes. Also, several groups of hardware experiments are implemented on a self-built hardware experiment platform, which verify the effectiveness of the proposed method.

Adaptive Sliding-Mode Control of an Offshore Container Crane With Unknown Disturbances

In this paper, an adaptive sliding-mode control (ASMC) for offshore container cranes that load/unload containers from a mega container ship to a smaller vessel is investigated. To withstand the harsh working conditions in the open sea, such as ship motions and winds, a 4-degrees-of-freedom control model consisting of plant uncertainties and known/unknown disturbances is newly developed. After decoupling the actuated (i.e., trolley displacements) and unactuated (i.e., swing angles) joint variables, a sliding surface that incorporates the decoupled dynamics is designed. Then, a new sliding-mode control (SMC) algorithm with two adaptation laws for switching- and equivalent-control inputs is developed. The asymptotic stability to the “real” sliding surface introduced in the decoupled (actuated, unactuated) state space is proven without a priori knowledge on the bounds of unknown disturbances. For the experiment, a three-dimensional crane mounted on a Steward platform to generate the ship motions is utilized. To verify the effectiveness of the proposed ASMC method, experimental results of the proposed method are compared with two representative works: the SMC presented by Ngo and Hong and the ASMC presented by Zhu and Khayati. The vibration suppression capability of the proposed method in the presence of ship motions, large initial swings, parameter uncertainties, and sudden disturbances is superior to the two compared methods. The developed algorithm can be used for a mobile harbor system as a new tool in the modern maritime industry.

Partially saturated coupled-dissipation control for underactuated overhead cranes

Abstract This paper proposes a partially saturated nonlinear controller for underactuated overhead cranes based on passivity. The main contribution is that the total energy shaping method yields an assignable storage function which is characterized by a desired damping matrix and especially quadratic in a new error vector of the coupling form. Consequently, a partially saturated nonlinear controller enforcing the coupled-dissipation inequality is derived to introduce additional damping terms to the sway angle, thus guaranteeing favorable transit performance. Owing to the elaborate structure of the coupled-dissipation term, the control system can achieve significant oscillation reduction over a wide range of cable lengths and transportation distances without readjusting the control gains. Besides the Lyapunov theory, LaSalle’s invariance principle is carried illustrating the corresponding stability. The proposed controller is evaluated through both simulation and experimental results that demonstrate the improved performance and robustness.

Perancangan Pengontrolan Overhead Crane Menggunakan Kabel dan Nirkabel Berbasis Arduino

Overhead Crane is a heavy equipment which is very much found in various industries, factories, and workshops that are used to transport material. In general, controlling the Overhead Crane is operated by using a Push Button that is hung together with a cable on the top frame of the Overhead Crane. in this case, humans must also be able to maintain a distance when controlling Overhead Cranes that are working to transport memterials to avoid the use of Overhead Cranes. To provide security and comfort in the use of Overhead Cranes, the authors designed an Overhead Crane controller using Arduino based cable and wireless. The design of Overhead Crane control using a cable consists of several series of Push Button arranged in a plastic box and then hung on the side of the Girder Crane. for the input foot the Push Button is given a voltage 12 VDC, while the output of the Push Button is connected with contact points of the Relay 12 VDC to execute electrically mechanical Overhead Crane. While the Overhead Crane control design using wireless consists of several components, including: Arduino Mega 2560 which is combined with USB Host Shield. Bluetooth csr 4.0 Dongle is connected to the USB Host Shield port for data communication media between Arduino Mega 2560 with Bluetooth Joystick PlayStation 3 (PS3). The signal pin of the Relay modules is connected with Arduino Mega 2560 pins according to the program designed. Contact NO points Relay modules are connected with 12 VDC Relay point contacts to execute electrical mechanical Overhead Crane.

Partially saturated coupling-based control for underactuated overhead cranes with experimental verification

This paper presents a partially saturated coupling-based controller for underactuated overhead cranes. A new storage function characterized with a desired inertia matrix and potential energy function is constructed, which is especially quadratic in a composite state vector, and subsequently, a nonlinear controller is designed by enforcing the coupled-dissipation inequality. Particularly, a composite signal is fabricated to augment the internal coupling between the trolley movement and the payload sway, thus drastically increasing the damping of the control system. The proposed controller is simple and very robust to different/uncertain cable lengths. Besides, the hyperbolic tangent function is adopted so that the proposed controller guarantees a soft trolley motion. In the frame of the Lyapunov theory, LaSalle’s invariance principle is applied to illustrate the asymptotical stability. Simulation and experimental results are presented to verify the effectiveness of the control system.

Dynamics of luffing motion of a flexible knuckle boom crane actuated by hydraulic cylinders

In this paper we present a modeling procedure for a flexible knuckle boom crane, which is actuated by hydraulic cylinders and is modeled as a planar multibody system. We propose a convenient framework where both rigid body velocities and velocities caused by flexible behavior are represented as twists. Such formulation allows for using screw transformations, which leads to systematic derivations. Dynamics of a crane and mass balance of hydraulic cylinders are coupled using the bond graph method. In addition, we present a procedure for the determination of reaction forces in passive joints, which is conveniently given as an extension of the dynamic modeling procedure. Both procedures are presented in a general and systematic manner such that they can be applied for a group of planar flexible manipulators.We study the dynamics of luffing motion of a crane by numerical simulation and provide the simulation results, as well as determine the reaction forces in passive joints. The simulation results are validated by the ANSYS finite element analysis. The derived model provides a basis for design of luffing cylinders and can potentially be used for studying performance of a crane control system.

Adaptive control of uncertain underactuated cranes with a non-recursive control scheme

In this paper we consider the adaptive control of underactuated crane systems with unknown system parameters. A novel non-recursive control scheme is proposed for the underactuated crane systems with a time-varying control gain. The parameter estimators design for the unknown parameters is also avoided. It is shown that the stabilization errors of the underactuated crane systems converge to origin asymptotically. Finally simulation results are carried out to verify the effectiveness of the proposed schemes.

Payload twisting dynamics and oscillation suppression of tower cranes during slewing motions

Challenging and dangerous material-handling applications in construction have motivated the study of the dynamics and control of tower cranes. Manipulating tower cranes is difficult while moving large-size payloads because of the inevitable payload swing and twisting about the cables. Although significant work has been directed at reducing the swing of point-mass loads, much less effort has been directed at limiting the payload twisting. A nonlinear dynamic model of tower cranes carrying distributed-mass beams is described. Furthermore, an open-loop control method is proposed to reduce both the swing and twisting of the payloads during slewing motions. Simulations and experiments demonstrate the theoretical dynamic behavior of the model and validate the effectiveness of the proposed control method.

Efficient swing control of an overhead crane with simultaneous payload hoisting and external disturbances

Abstract The effects of time varying parameters and external disturbances on a flexible system may badly degrade the control performance resulting in excessive induced vibrations/oscillations. For an overhead crane, the oscillation can be even worse when both factors occur simultaneously. This paper proposes a novel swing control approach for an underactuated overhead crane having payload hoisting and external disturbance simultaneously. The proposed scheme is designed based on a predictive unity magnitude shaper and an adaptive feedback control which efficiently suppress payload swing to handle both effects. Furthermore, the control parameters can be updated online in real time to progressively suppress the payload swing. To evaluate the effectiveness of the proposed method, experiments are carried out with a simultaneous payload hoisting and external disturbances including a non-zero initial condition, persistent disturbance (wind) and instant disturbance. The developed controller achieves higher robustness under all testing conditions with significant swing reductions of at least 45% and 69% in the overall and residual swing responses, respectively over a comparative control method. It is envisaged that the proposed method can be very beneficial as an anti-swing controller for various cranes under the influence of disturbance and hoisting simultaneously.

Research on Nonlinear Control Method of Underactuated Gantry Crane Based on Machine Vision Positioning

The movement of the gantry crane is controlled by an symmetry underactuated system, and has poor robustness in precise positioning. A new active control method based on the machine vision positioning is proposed in this paper, and the trajectories are planned after the detection of starting and ending points. A new type of energy storage function is given in this paper, and a coupling control law is derived to minimize the load swing in the process of precise positioning. The equilibrium point of the closed-loop system is checked though Lyapunov and LaSalle’s theorems, and the calculation results are verified through experimental investigations. The results show that the equilibrium points are asymptotically stable, and the proposed control method is of better robustness. The findings provide a new kind of control method with higher efficiency, and can help with the precise control of gantry cranes.

Transportation Control of Double-Pendulum Cranes With a Nonlinear Quasi-PID Scheme: Design and Experiments

In real-world applications, industrial cranes commonly suffer from effects caused by the so-called double-pendulum phenomenon in many situations. However, at present, the double-pendulum phenomenon is usually directly roughly neglected when designing control methods. For double-pendulum cranes, most currently available approaches are open loop control; the existing feedback methods are mostly developed based on linearized dynamic models (around the equilibrium point) or designed without adding integral terms in the control laws, which may cause positioning errors in the presence of unmodeled dynamics. To address these problems, this paper proposes a new quasi-proportional integral derivative control method to effectively control underactuated double-pendulum crane systems. Then, we provide rigorous theoretical analysis for the equilibrium point of the closed-loop system based on the original nonlinear dynamic equations. To our knowledge, this paper gives the first plant-parameter-free controller that incorporates both integral action and actuating constraints without any linearizing operations during controller design or closed-loop analysis, which theoretically ensures that the controller can work well in the presence of unmodeled dynamics (e.g., insufficient friction compensation), actuating constraints, and large swing angles (i.e., not satisfying linearization conditions). Finally, hardware experimental results are provided to examine the effectiveness of the suggested control method.

Adaptive Anti-Swing and Positioning Control for 4-DOF Rotary Cranes Subject to Uncertain/Unknown Parameters With Hardware Experiments

Among various large-scale mechanical equipments, a rotary crane is one of the most practical hoisting machineries utilized in factories and docks. However, the inaccurate measurement of friction coefficients and the requirement of accurate gravity-related compensation may inevitably increase the difficulty for controlling such systems. For most existing control methods, the exact model knowledge is required; otherwise, positioning errors would unavoidably appear, which brings many limitations for their practical applications. To deal with these problems, in this paper, a novel adaptive control approach is suggested, in which a novel update law is designed to achieve accurate identifications of unknown parameters as well as exact compensation of the gravity-related lumped term. Moreover, the payload can be transported to its specified location precisely via the boom’s rotation with effective payload swing suppression. Specifically, without linearizing the nonlinear dynamic model of the rotary crane system, the state variables are ensured to be asymptotically convergent to the equilibrium point, which is proven strictly in theory by utilizing Lyapunov techniques and LaSalle’s invariance principle. Finally, experimental results indicate the effectiveness and practicability of the proposed approach.