Sway Suppression Research Articles

컨테이너 크레인의 흔들림 억제 제어에 관한 연구

In this paper, we consider the sway suppression control problem for container cranes with load hoisting. The proposed control law improves the positioning accuracy but also the sway suppression through fast stabilization of the under-actuated sway dynamics, which is based on a class of feedback linearizing control incorporated with an additional control including the sway angle and its rate as well as positioning errors and their rates. For the design of the additional control, a variable structure control with the proper sway damping and simple switching action is employed, thus preventing excessive overshoots of the trolley travelljng and effectively suppressing the residual sway of container arrived at the target position. Simulation results are provided to show effectiveness of the proposed controller in the presence of such uncertainties as winds and the variation of payload weights.

An Anti-Swing and Positioning Controller for Overhead Cranes Based on Multi-Sliding Mode Method

Overhead cranes are essentially a kind of complex underactuated nonlinear mechanical systems, and it is a challenge to design an anti-swing controller for overhead cranes, hence, many people design controllers of overhead cranes ignoring the changing of the rope length and other parameters. In this study, we propose a multi-sliding mode controller to solve the problem of anti-swing and positioning controller for an overhead crane with rope length variations. This controller can provide a simultaneous trolley-position regulation, sway suppression, and load hoisting control. Also, this paper adopts a new method to decrease the chattering of the control input. Stability analysis of the proposed controller is given in the paper. The proposed controller does not rely on the accurate knowledge of overhead crane system model, and it is simple and easy to apply, and robust to disturbances. The simulation results show the good performance of the proposed controller.

S151016 クレーンの制振搬送訓練シミュレータの開発

Expert skill is needed to operate a crane and transfer load without exciting the load sway. Typical teaching method such as explain verbally is difficult to be understood. Recently, a crane simulator is used to learn operator skill of crane. However, its time of training is no great distinction between a crane simulator and actual crane. In this paper, a simulator capable of shortening the training period of unskilled crane operators is newly built. First, referring to the sway suppression skill taught in crane driving school, sway suppressing control input is derived theoretically. Next, a learning support method that presents haptic and visual sensory information to facilitate acquisition of the sway suppression skill by the unskilled operators is proposed. An experiment was performed to validate the effectiveness of the proposed learning support method and the results indicate that proposed method can be beneficial in the training of crane operators.

Analysis and Experiment of Residual Load Sway Suppression in Rotary Crane Systems Using Simple Trajectory for Horizontal Boom Motion

To suppress two-dimensional load sway caused by the horizontal boom motion of a rotary crane, both horizontal and vertical boom motions are generally used. However, it would be more energy efficient and safer if a control scheme is developed that only used horizontal boom motion, eliminating the need for any vertical boom motion. In addition, if we can suppress load sway without the need to measure it, reduction in the cost of sensors can be achieved. Furthermore, use of simple velocity trajectory patterns such as a trapezoidal velocity pattern and an S-curve acceleration/deceleration pattern, which are widely used in industrial automation systems, may provide costeffective implementation of controllers. This study examines the analytical conditions for a simple S-curve trajectory of horizontal boom motion to suppress residual load sway without sensing it. Numerical simulation and experimental results demonstrate the effectiveness of the proposed conditions.

103 アクティブジョイスティックを用いたクレーン制振搬送の教示システム構築(OS1-1 人間とロボットの共生(1),OS1 人間とロボットの共生)

103 アクティブジョイスティックを用いたクレーン制振搬送の教示システム構築(OS1-1 人間とロボットの共生(1),OS1 人間とロボットの共生)

S-Curve Trajectory Generation for Residual Load Sway Suppression in a Rotary Crane System Using Only Horizontal Boom Motion

Generally, both horizontal and vertical boom motion must be used to suppress the load sway caused by horizontal boom motion of a rotary crane. However, it would be less energy intensive and also safer if a control scheme could be developed that only used horizontal boom motion, i.e., without the need for any vertical boom motion. In addition, if load sway can be suppressed without measuring it, reduction in sensor cost can be achieved. Furthermore, employing simple velocity trajectory patterns such as trapezoidal and S-curve patterns, which are widely used in industrial automation systems, may provide cost effective controller implementation. This study presents a simple S-curve trajectory generation method for rotary crane motion that can suppress residual load sway using only horizontal boom motion without load sway sensing. Numerical simulations and experimental results demonstrate the effectiveness of the proposed method.

Wheelchair Driving Control Considering Sway Suppression to Passenger's Posture and Evaluation of Ride Quality

Abstract This paper presents an advanced control system for a driving control system of an electrical wheelchair. The aim of the control system is to make possible a comfortable ride in the wheelchair. For this, a passenger model has been constructed and a driving pattern that suppresses sway of passenger's posture has been developed using optimization methods. In the passenger model, it is represented that the passenger's body contacts a backrest in the wheelchair in order to represent precisely the passenger's posture behavior. The proposed passenger model is used to design the driving pattern of the wheelchair. In design of the driving pattern, the sway of the passenger's posture and the traveling time are minimized by the sequential quadratic programming. Then, the quality of the ride whiles a passenger is transferred by the wheelchair has been evaluated by a questionnaire and by measurements of emotional sweating. In comparison with the conventional driving pattern, the proposed driving pattern suppresses about half of the passenger's posture behavior by the conventional pattern and improves the comfort of wheelchair driving.

Hybrid Fuzzy Logic Control with Input Shaping for Input Tracking and Sway Suppression of a Gantry Crane System

Problem statement: Most of the common gantry crane results in a sway motion when transporting the load as fast as possible. In addition, precise cart position control of gantry crane must required a zero or near zero residual sway. Approach: In this study, the development of hybrid control schemes for input tracking and anti-sway control of a gantry crane system was investigated. To study the effectiveness of the controllers, a Proportional-Derivative (PD)-type fuzzy logic control was developed for cart position control of a gantry crane. It was then extended to incorporate input shaper control schemes for anti-sway control of the system. The positive and new modified Specified Negative Amplitude (SNA) input shapers were designed based on the properties of the system for control of system sway. The new SNA was proposed to improve the robustness capability while increasing the speed of the system response. Results: Simulation results of the response of the gantry crane with the controllers were presented in time and frequency domains. The performances of the of the hybrid control schemes were examined in terms of input tracking capability, level of sway reduction and robustness to parameters uncertainty. Conclusion: A significant reduction in the system sways had been achieved with the hybrid controllers regardless of the polarities of the shapers.

Hybrid Fuzzy Logic Control with Input Shaping for Input Tracking and Sway Suppression of a Gantry Crane System

Hybrid Fuzzy Logic Control with Input Shaping for Input Tracking and Sway Suppression of a Gantry Crane System

The Development of an Autonomous Mobile Crane System Considering On-Line Obstacle Recognition and Path Planning

The purpose of this paper is to present a method to establish an autonomous mobile crane system which includes on-line obstacle recognition, path planning by on-line and suppression of sway of the transferred object. The system consists of three different parts: a visual system, a planning system and a control system. In the visual system, ultra sonic sensor is used to renew small part of environmental map during the transferring taking advantage of quick scanning time. In the planning system, proposed on-line path planning method is used in an artificial potential field based on the solution of the Laplacian differential equation. This path planning method can correspond to minor changes in the transportation environment during transportation. The on-line path planning has been accomplished by regenerating the updated potential field. In the control system, feed-forward controller by means of notch filter is used to achieve the suppression of sway of the transferred object. Finally, the usefulness of the proposed method is confirmed by simulations and experiments.

Digital Filter Based Motion Command Preconditioning of Time Varying Suspended Loads in Boom Cranes for Sway Suppression

Due to the presence of suspended loads, transient and residual sway is present when a motion command is applied to a crane. Various methods for sway suppression have been proposed, based either on closed loop control or command preconditioning procedures. Among command preconditioning methods, conventional FIR filters, when properly designed, have been shown to present in general extremely robust behavior, combined with the introduction of the minimum possible delay. Thus, these filters are proposed for preconditioning the motion commands of boom cranes, the dynamic response of which is strongly non-linear and time varying, characterized by large variations of the sway natural frequencies. Signal processing techniques are exploited for the analysis of the dynamic response of the crane system, and the results of this analysis are applied for the design of the preconditioning procedures. Two alternative methodologies are presented, aiming at sway suppression of the system, and the minimum possible motion duration. It is shown that the use of filtered inputs effectively suppresses payload sway during and after the mechanism motion, while the smooth nature of the resulting response leads to significant decrease in the stress levels induced on the motors and the structure of the crane.

THE ON-LINE OBSTACLE RECOGNITION, PATH PLANNING AND TRANSFERRING OF AN OVERHEAD CARNE SYSTEM

This paper presents a method to establish the three-dimensional (3-D) autonomous mobile overhead crane system which takes into account obstacle recognition and path planning by on-line and suppression of sway for the transfer object. The system has three different parts: a visual system, a planning system and a control system. In the visual system, ultra sonic sensor is used to renovate partial environmental map during the transferring in terms of the quick scanning time. In the planning system, proposed on-line path planning method which use an artificial potential field based on the solution of the Laplacian differential equation that can correspond to on-line processing like a change in the transportation environment during transportation. The accomplishment of on-line path planning has carried out by redeveloping the updated potential field. The algorithm in on-line planning system is proposed through the use of off-line planning system. In the control system, feed-forward controller with terms of notch filter is used to achieve the suppression of sway for the transfer object. Finally, the validity of the proposed method is confirmed by simulation and experimental results.

Sway Control of Overhead Travelling Crane Considering Coupled Vibration

One degree of freedom model has been used in many problems regarding dynamic analysis for overhead traveling crane. However, various loadings are carried out using a sling rope with increase of workplace. Therefore, crane operation conditions have been expanded in the field work. It is very important of safety and efficiency to operate an overhead traveling crane to suppress load sway. In general, there are two varieties of load sway of overhead traveling crane problem. One is a cart moving, another is after the cart stops. A load sway suppression method to the overhead travelling crane is proposed and discussed. First, in order to analyze the crane traveling motion, a simple two degrees of freedom model considered both of load and hook mass, is proposed. Second, a load sway suppression method is presented. In this method, optimally controlled traveling velocity is available by using the natural period of the crane which gives the minimum energy of the two degrees of freedom model system. The effectiveness of the method is confirmed by a numerical calculation and a model testing.

318 天井クレーンの荷揺れ抑制搬送に関する研究

A load sway suppression method to the overhead travelling crane is proposed and discussed. First, in order to analyze the crane traveling motion, a simple two degrees of freedom model considering load mass and hook is proposed. Second, a load sway suppression method is presented. In this method, optimally controlled traveling velocity is available by using the natural period of the crane which gives the minimum energy of the two degrees of freedom model system. The effectiveness of the method is confirmed by a numerical calculation and a model testing.

134 2自由度モデルによる天井クレーンの荷揺れ抑制手法の研究(制振・免振装置の開発, OS-11 ダンピング(2))

134 2自由度モデルによる天井クレーンの荷揺れ抑制手法の研究(制振・免振装置の開発, OS-11 ダンピング(2))

Payload sway suppression in rotary cranes by digital filtering of the commanded inputs

A method is proposed for the suppression of the sway of rotary crane payloads. In contrast to closed-loop control methods which encounter significant practical application problems, the proposed method is based simply on the preprocessing of all the commanded crane inputs by a properly designed finite impulse response (FIR) filter. A four-degrees-of-freedom (4DOF) model for the rotary crane system is considered, incorporating both the hoisting and the slewing motions and thus able to handle cases where hoisting can be simultaneously applied to the rotary motion. Although the resulting dynamic system is strongly non-linear and time varying, the method is shown effectively to suppress, in a quite robust, time and energy efficient way, both the transient as well as the residual sway of the payload. Moreover, additional advantages of the proposed method are that no dynamic modelling of the crane is required, and that the applicability of the method is quite easy and general, without the need for any additional instrumentation and control equipment.

Role of Visual Feedback in Upright Posture Control

We studied the role of visual feedback in upright posture control on the sagittal plane. In posture control, each sensory system has the following roles: initial detection of sway, suppression of short-term sway around the equilibrium point, and suppression of longterm sway induced by a slow shift in equilibrium. Experiments were conducted to examine features of each sensor and then visual contribution was studied. Based on measured sensory thresholds for the perception of sway during standing, it was suggested that visual input provided sensitive means of perceiving postural sway. Body sway of a subject was measured under several conditions in which the subject controlled upright posture utilizing the definite number of sensors. By analyzing and comparing measured sway waveforms under each condition, it was clear that the visual system suppressed short-term sway. Spectral analysis showed that the visual system suppressed body sway in a low frequency range around 0.2 Hz. Though visual feedback contains a large time delay, the influence of the delay is small in the low frequency range. It is rational that vision is efficient at suppressing body sway in the low frequency range.

Two-Stage Control for Container Cranes.

For fast loading/unloading of the containers from a container ship, the quick suppression of the residual sway of the container at the end of trolley traveling is crucial. Due to the unmodeled dynamics of the plant and to disturbances like wind, a residual sway always exists. In this paper, a two-stage control for container cranes is investigated. The first stage control is a modified time-optimal control with feedback for the purpose of fast trolley traveling. The second stage control is a nonlinear control for the quick suppression of the residual sway while lowering the container at the target trolley position. The secondary control combines the partial feedback linearization to account for the unknown nonlinearities as much as possible and the variable structure control to account for the unmodeled dynamics and disturbances. The nonlinear control is investigated from the perspective of controlling an underactuated mechanical system. Simulations and experimental results are provided.

天井クレーンのポテンシャル法を用いた三次元パスプランニング

This paper presents a method for path planning and motion execution of overhead travelling crane with three dimensional transport, considering the both of obstacle avoidance and suppression of sway for transfer objects. The present research is done based on a given geometrical map in environments for off-line application, as the basic step to establish autonomous mobile crane systems in future factory. A potential approach using a three-dimensional diffusion equation is applied to the present path planning. The moving direction and magnitude in each step are respectively calculated by the proposed vector-composite method and the allowable maximum values of acceleration and velocity constrained from the hardware capacity. Further, in order to avoid the collision with obstacles especially around the steep corner, a holding method is proposed by the introduction of the concept of a steering angle between the moving direction at the present position and the direction to be moved calculated from the potential field at the stopping-position of some-step ahead. The usefulness of this paper is demonstrated through computer simulations and laboratory experiments.

Path Planning and Motion Execution of Overhead Travelling Crane

This paper presents a method for path planning and motion execution of overhead travelling crane with three dimensional transport, considering the both of obstacle avoidance and suppression of sway for transfer objects. The present research is done based on a given geometrical map in environments for off-line application, as the basic step to establish autonomous mobile crane systems in future factory. A potential approach using a three-dimensional diffusion equation is applied to the present path planning. The moving direction and magnitude in each step are respectively calculated by the proposed vector-composite method and the allowable maximum values of acceleration and velocity constrained from hardware capacity.