Anti-sway Control Research Articles

Adaptive Sliding-Mode Antisway Control of Uncertain Overhead Cranes With High-Speed Hoisting Motion

This paper proposes an adaptive sliding-mode antisway control law for uncertain overhead cranes with high-speed hoisting motion. Since the sway dynamics are disturbed by the trolley acceleration and hoisting velocity, antisway control law is designed based on the sliding mode control by defining a sliding surface in such a way that the trolley acceleration contributes to the sway dynamics as nonlinear damping in sliding mode. In addition, this nonlinear damping is designed such that it dominates the inherent damping coupled with the hoisting velocity so that the asymptotic stability of the sway dynamics can be achieved. To cope with system uncertainties such as system parameter variations, unknown actuator nonlinearities, unmodeled dynamics, and external disturbances, we design a fuzzy uncertainty observer and incorporate it into the sliding-mode antisway control law. Via the stability analysis and computer simulations, we show that the proposed control law guarantees the robust antisway performance of overhead cranes, regardless of hoisting velocity, even in the presence of system uncertainties.

Nonlinear model predictive control of hydraulic forestry crane with automatic sway damping

Forest machines are used in many tasks and come in various designs. They can be used for cutting down trees, collecting logs and in different forest cleaning operations. Currently, in the commercial machines the level of automation is still relatively low, and they require a professional operator for good work efficiency. Nonlinear model predictive control (NMPC) is an optimal control strategy based on a dynamic model of the system. NMPC algorithms require quite a lot of computational power, but are becoming a more viable option as the performance of computers has increased. We demonstrate how an NMPC can be used for controlling a hydraulic forestry crane that has a freely hanging tool or processing head attached. The goal of the control is to follow a predefined path while simultaneously damping the undesired oscillations of the tool. Three different reference paths with velocities of 0.5m/s to 1.0m/s are tested. The average tracking error in these tests is between 0.02m and 0.11m. Anti-sway control can reduce the amplitude of sideways oscillations between 2% and 64% and longitudinal oscillations between 59% and 76%. The impact of anti-sway control on the tracking accuracy or the velocity is negligible.

Anti-Sway Control Schemes of a Boom Crane Using Command Shaping Techniques

This paper presents investigations into the applications and performance of command shaping techniques for control of payload sway of a boom crane based on filtering and the input shaping technique. The mathematical dynamic model describing the motion of the boom crane is developed using the Lagrange-Euler's equation. The dynamic characteristics of the system are studied and analysed using the Matlab Simulink in time and frequency domains. Command shaping techniques based on filtering and the input shaping techniques are then developed and used to control the payload sway of the boom crane. The performance of the control techniques are studied in terms of the level of sway reduction, time response and robustness. Finally, a comparative assessment of the effectiveness of the control schemes for sway control of a boom crane is presented and discussed.

Load Position Estimation for Crane Anti-Sway Control Systems

A rising number of modern cranes are equipped with anti-sway control systems to facilitate crane operation, improve positioning accuracy, and increase turnover. Commonly, these industrial crane control systems require pendulum state information for feedback control. Therefore, a pendulum sway sensor (e.g., a rope-mounted gyroscope) and a signal processing algorithm are required. Such a signal processing algorithm needs to filter out disturbances from both the sensor and the crane, e.g., signal noise and string oscillations of a long rope. Typically, these signal processing algorithms require the knowledge of the acceleration of the rope suspension point. This acceleration signal is often estimated from drive models. When drive models are uncertain, the pendulum state estimation accuracy suffers from drive model inaccuracy. In this contribution, an improved estimation algorithm is presented which estimates the load position without relying on the rope suspension point acceleration. The developed Extended Kalman Filter is implemented on a Liebherr mobile harbor crane and its effectiveness is validated with multiple test rides and GPS load position reference measurements.

Fuzzy crane control with sensorless payload deflection feedback for vibration reduction

Different types of cranes are widely used for shifting cargoes in building sites, shipping yards, container terminals and many manufacturing segments where the problem of fast and precise transferring a payload suspended on the ropes with oscillations reduction is frequently important to enhance the productivity, efficiency and safety. The paper presents the fuzzy logic-based robust feedback anti-sway control system which can be applicable either with or without a sensor of sway angle of a payload. The discrete-time control approach is based on the fuzzy interpolation of the controllers and crane dynamic model's parameters with respect to the varying rope length and mass of a payload. The iterative procedure combining a pole placement method and interval analysis of closed-loop characteristic polynomial coefficients is proposed to design the robust control scheme. The sensorless anti-sway control application developed with using PAC system with RX3i controller was verified on the laboratory scaled overhead crane.

Simulation and Analysis of the Anti-Sway Control of Crane Ship Based on Adams and Matlab Co-Simulation

The thesis established the virtual prototype model of the crane ship based on the software platform of Adams and designed the control program to control the virtual model based on Matlab/Simulink. In the ideal working condition for crane ship, the co-control effectively reduces the swing angles of the hoist by the control program of open-loop control.In the working condition when the ship has more substantial movements, Adams and Matlab co-simulation reduces the swing angles of the hoist by the control program of open-loop control to change the pitching angle and slewing angle of the boom.

Sway Estimation using Inertial Measurement Units for Cranes with a Rotating Tool

Cranes have often a freely hanging load or tool that starts easily swaying. Anti-sway control requires that the angles and angular velocities of the swinging object are measured. Some cranes can also rotate the tool with a hydraulic motor, and in many cases this rotator angle should also be known. Instrumenting all three axes, two swaying and one rotating axis, with traditional rotary encoders can be challenging. We propose an extended Kalman filter based system using two inertial measurement units. This system can measure the swaying in both directions and estimate the rotator angle. Computer vision system is used as reference. The initial results show that the error is approximately 5 degrees in the rotator angle and 2 degrees in the sway angles. The observer runs at 100 Hz on an embedded microcontroller.

Robust design of vibration suppression control system for crane using sway angle observer considering friction disturbance

AbstractIt is desirable for a container crane to operate smoothly and quickly. For this purpose, the control system of a container crane should be capable of antisway control for suppressing vibrations. A vision sensor system is often used to detect the sway angle. However, since a control system with a vision sensor has a delay time when determining the angle, it sometimes leads to deterioration of control performance owing to the delay time. In order to overcome this problem, this paper proposes a new antisway crane control system based on a dual‐state observer with sensor‐delay correction. However, because of nonlinear friction in the crane, the estimation accuracy achieved by using the observer is poor. To overcome this problem, this paper proposes a disturbance observer considering friction disturbance. The control performance and effectiveness of the proposed robust control system based on the estimated information are shown to be satisfactory by experimental results. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(3): 36–46, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22412

The Anti-Sway Crane Control System with Using Dynamic Vision System

The paper presents the mechatronic approach to design a robust anti-sway crane control system on the laboratory stand, physical model of an overhead traveling crane. The core of a problem in realizing the anti-sway crane closed-loop control system in industrial practice is the reliable technique of measuring swing angle of payload suspended on a rope. Thus, the contactless method utilizing dynamic vision system is proposed in the paper. The poles assignment-based method of fuzzy gain scheduling crane control system designing is applied to built the crane control scheme. The software and hardware equipment of laboratory stand allows to automate the process of prototyping the control system and built the control application based on the programmable logic controller (PLC).

Genetic Fuzzy Approach for Designing a Gain Scheduling Anti-Sway Crane Control System

The gain scheduling control scheme designing problem consists in selecting a set of appropriate operating points at which the linear controllers are determined, thus the interpolation scheme ensures expected control quality within the known range of system's parameters changes, when those parameters vary in relation to some exogenous variables used in a control system as the scheduling variables. The problem arises together with the number of scheduling variables correlated with the parameters variations, thus utilizing the iterative techniques to minimize a set of controllers can be unreliable. The problem of gain scheduling system designing is addressed in the paper to the anti-sway crane control system. The fuzzy interpolation is used to determine the gains of proportional-derivative controllers based on the scheduling variables, the rope length and mass of a payload suspended on a rope. The problem of rules base optimization and membership function parameters tuning is solved using genetic algorithm and pole placement method.

D08 3次元空間の位置検出用ジャイロセンサの開発 : 旋回クレーンの振れ止め制御への適用(M-OS4-2 制御用センサと空気圧アクチュエータの応用,M-OS4 制御用センサ・アクチュエータ,「海を越え,国を越え,世代を超えて!」)

The purposes of controlling the crane are to transfer the cargo to the target point as quickly as possible with suppressing the swaying and to quickly minimize the residual sway at the target point. At present, the development of the anti-sway control system for a rotary crane is desired, because the operation of a rotary crane which achieved by cargo windup, boom derricking and boom slewing is very difficult. So, variety sensors to measure the condition of a cargo and controlled methods to reduce the sway are proposed. In this paper, we show to be able to obtain the position of a cargo on three dimensions space by using the IMU, even if the attitude direction of cargo is unstable. And we tried to suppress the sway a cargo by experimental device.

バックステッピング法に基づく旋回クレーンの振れ止め制御

The basic motions of the slewing crane as construction machines are classified into cargo windup, boom derricking and boom slewing. The purposes of controlling the crane are to transfer the cargo to the target point as quickly as possible with suppressing the swaying and to quickly minimize the residual sway at the target point. At present, the crane operation depends on the skill and sense of the operator, so its automatic operation is desirable from the standpoint of economy and safety. Concerning the anti-sway control of a rotational crane, several methods are known; that based on an optimum reference pattern suppressing the swaying, that based on the feedback control system using a linear approximation around θ, and that based on θ=tan-1F(x,y) proposed by authors. However, the first and the second methods are not effective for the disturbance such as a wind, and the third one is unstable when the denominator =0 of tan-1F(x,y). So, we have developed the method based on the idea of the backstepping approach and have got remarkable effects.

Anti-Sway Crane Control Considering Wind Disturbance and Container Mass

A method for estimating the sway angle using an observer has already been proposed. The state observer estimates the sway angle accurately, and has to use the detected sway angle value. However, the estimated sway angle has an error owing to rope length error, friction force, and wind. Moreover, the container mass cannot be determined, therefore, the observer parameter is not suitable. We already proposed robust anti-sway control for overcoming rope length error without adding a new sensor. Further, we designed a friction disturbance observer to cancel out the influence of friction force. In this paper, we first propose a container mass estimation method when crane system performs rolling up control. The observer parameter can be selected by an estimated mass value. Second, in crane parallel shift control, we propose a robust anti-sway control even with wind disturbance. We design a wind disturbance observer and propose a wind disturbance estimator to separate the friction observer output from the wind disturbance observer output. We confirm via experiments that the proposed method can suppress vibration.

Dynamic and Control Strategy of Payload Motion for Deployment System

The dynamic model of wire rope with contact is presented based on finite element method and the flexible multi-body dynamics theory by putting the contact force between the wire rope and drum. The unilateral anti-sway and tension control strategy is put forward, and the dynamic model and collaborative simulation of payload motion for deployment system is modeled by dynamic analysis software RecurDyn and control library Colink. The correctness of the collaborative simulation model and control strategy is validated by analysis and comparison , which lays the foundation for further research on dynamic simulation of virtual prototype in nonlinear and complex mechanical-control system.

摩擦外乱オブザーバを拡張したクレーン振動抑制制御系のロバスト化の一検討

It is desirable for a container crane to operate smoothly and quickly. For this purpose, the control system of a container crane should be capable of antisway control for suppressing vibrations. A vision sensor system is often used to detect the sway angle. However, since a control system with a vision sensor has a delay time when determining the angle, it sometimes leads to deterioration of control performance owing to the delay time. In order to overcome this problem, this paper proposes a new antisway crane control system based on a dual-state observer with sensor-delay correction. However, because of nonlinear friction in the crane, the estimation accuracy achieved by using the observer is poor. To overcome this problem, this paper proposes a disturbance observer considering friction disturbance. The control performance and effectiveness of the proposed robust control system based on the estimated information are shown to be satisfactory by experimental results. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(3): 36–46, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22412

Fuzzy rules-based approach to estimate the availability of transportation system

The productivity of manufacturing process significantly depends on an availability of material handling systems, which in turn depends on reliability and maintainability of transportation devices. For this reason the scheduling of maintenance operations is very important to keep the high availability of transportation system. The attention in the paper is focused on a crane control problem and availability of automated material handling device, which refers to capability of a device to realise transportation operations with expected quality. An anti-sway crane control problem was solved in the paper by using indirect adaptive pole placement system with fuzzy estimator of parameters of a crane dynamic model. The paper presents the fuzzy model used to heuristic estimation of the system availability coefficient, and genetic fuzzy system that forecasts prognoses of operating time between failures. The models were implemented in the monitoring and diagnostic system tested on the laboratory stand, the overhead travelling crane.

An Anti-Sway Controller’s Design of the Overhead Crane

This paper detailedly illustrates how to design an anti-sway controller of overhead crane for eliminating pendulum of hook-headed. First of all the paper uses Lagrange Equation in analytical mechanics to obtain a mathematical model of crane motion system in three dimensional space. Then the paper advances a new control method and designs an anti-disturbance tracking controller based on servo-compensator and stabilization compensator for eliminating pendulum of hook-headed and accurately fixing position. In general, it is difficult to design an appropriate control law because of the crane motion system’s nonlinearity and strong coupling. However, the control method the paper put forward is simple and effective, and ensures the transient state performance of closed-loop system preferable and stable. The paper will introduce the design steps of anti-sway controller of overhead crane and give a satisfying simulation result, which are new and original in this paper.

C202 バックステッピング法に基づく旋回クレーンの振れ止め制御(振動の解析と制御)

The basic motions of the slewing crane as construction machines are classified into cargo windup, boom derricking and boom slewing. The purposes of controlling the crane are to transfer to the target point the cargo as quickly as possible with suppressing the swaying and to quickly minimize the residual sway at the target point. At present, the crane operation depends on the skill and sense of the operator, so its automatic operation is desirable from the standpoint of economy and safety. Concerning the anti-sway control of a rotational crane, several methods are known. We have developed the method based on the idea of the backstepping approach and have got remarkable effects.

Application of LQR Techniques to the Anti-Sway Controller of Overhead Crane

This paper explains and demonstrates how to design an anti-sway controller of overhead crane for eliminating pendulum of hook-headed. In this paper, we use Lagrange Equation in analytical mechanics to obtain a mathematical model of crane crab motion system. Then the paper comes up with a piece of new idea, i.e. applies linear quadratic regulator techniques to the anti-sway controller’ design of overhead crane. In order to make the designed linear optimal system meet the practical production requirements better, we use a parametric formula’s method of solutions to LQ inverse problems to obtain the weighting matrix Q. In fact, the method is simple and practical, and ensures the performance of closed-loop system is optimized. The paper will introduce the design steps of anti-sway controller of overhead crane and realization of anti-sway controller, which are new and original in this paper.

부유체 위에 고정된 크레인의 안정화 제어기 설계에 관한 연구

This paper deals with an anti-sway control for a ship-mounted container crane which is disturbed by the wave-induced motions of the ship. We derive a simple dynamics of the ship-mounted container crane with an active anti-sway control system and transform it into a dynamic function for a horizontal variable on the absolute coordinate. Then we propose an control method to reduce pendulation of the spreader and compare its performance with well-known feedback linearization control in computer simulation.