Hybrid Shape Approach Research Articles

Simulator Building for Agile Control Design of Shipboard Crane and its application to Operational Training

AbstractIn this paper, an integrated computer simulator tool of rotary crane with ship behavior in consideration of ship sway and load sway is newly built to systemize the state analysis of a shipboard crane. The integrated simulator of shipboard crane was realized by cooperating a component of external force interface routine and fluid analysis software. A transfer control system is conducted by HSA (Hybrid Shape Approach) using STT (Straight Transfer Transformation) method and its effectiveness in suppressing the sway of both ship and load was confirmed by the simulation analysis. A shipboard crane operational training system which we call virtual coach teaching system, is also presented, in order to shorten the training period of amateur operators. The controlled inputs generated from HSA controller which are utilized as the ideal commands are then converted to drive a newly built teaching interface. Subjects are physically coached through the ideal motion of joystick by placing their hand on the teaching interface, thus giving them a kinesthetic understanding on how to transfer a load without exciting the sway of both the ship and load. Performance of subjects was measured in terms of transfer time by conducting an experiment using a newly built virtual driving simulator. Findings from this study indicate that virtual coach teaching is effective in training.

Supervisory control of automatic pouring machine

This paper presents supervisory control of a total molten-metal pouring system to improve the productivity of the factory, the safety of workers, and the quality of the product. Through the pouring processes model, a forward tilting control input was calculated by an adaptive feedforward control system to hold the liquid in the sprue cup at a constant level considering the change effected by the accumulating slag in the ladle. A backward tilting input was obtained by means of the hybrid shape approach applied to suppress the slosh. The supervisory control system reasonably switches from the forward tilting motion to the backward tilting motion by using model predictive control to achieve the accurate poured quantity. The validity of the proposed total control system was demonstrated through experiments.

Fast Shake Mixing Control with Low Air Entrainment

In this study, a fast shake mixing control system that allows control of the quantity of air entrainment, involving low mechanical stress and fluid bubbling by means of the suppression the sloshing of a fluid's surface, is developed. Mixing by means of horizontal shaking in a circular motion is addressed, with a CFD simulator being used for analysis of the liquid's behavior, and the quantity of air entrainment during mixing evaluated. To design a fast mixing control system, the hybrid shape approach was applied. In addition, a 3DOF robot manipulator was used to achieve an arbitrary mixing trajectory and velocity. As a result, air entrainment caused by the sloshing of the liquid's surface is elucidated. The effectiveness of the mixing control technique employing sloshing suppression is shown by simulations and experiments.

注湯・取鍋搬送の複合動作を伴う自走式自動注湯ロボットにおける円筒形状取鍋の注湯および液面振動抑制制御

This paper is concerned with development of self-transfer-type automatic pouring robot using a cylindrical ladle. Especially, the paper focuses on the pouring control of the cylindrical ladle and sloshing suppression during ladle transfer and tilting. In order to realize fast pouring, the robot's pouring system was constructed by a feed-forward controller with a system inverse to the pouring process. In order to suppress the sloshing of the liquid in the ladle, the natural frequency of the sloshing caused by the transferring and pouring motion was identified by short-term Fourier transform. The feedback controllers in the control system were then designed by the Hybrid Shape Approach using notch filters corresponding to the identified natural frequency of sloshing. The proposed pouring and sloshing suppression controls were applied to an automatic pouring robot that had both automatic detection of the mold's status filled or unfilled with liquid and tracking control to the mold. The effectiveness of the developed control system was shown through experiments.

CONTROL OF SELF-TRANSFER-TYPE AUTOMATIC POURING ROBOT WITH CYLINDRICAL LADLE

This paper is concerned with advanced control of self-transfer-type automatic pouring robot, with focus on the pouring control to cylindrical ladle and sloshing suppression (liquid vibration) control to the liquid in a ladle. In the pouring control, the flow rate model of cylindrical ladle is represented by LPV(Linear Parameter Varying) model, and FeedForward(FF) controller is then designed by using inverse systems of motor and flow rate model. In the sloshing suppression control, the natural frequency of sloshing of liquid in the ladle is varied by tilting ladle. Therefore, the natural frequency of sloshing is identified by using Short Time Fourier Transform, and the controllers are designed by Hybrid Shape Approach. The validity of proposed control system is demonstrated through experiments.

Predictive control of flow quantity and sloshing-suppression during back-tilting of a ladle for batch-type casting pouring processes

The purpose of this paper presents a method to predict the molten metal quantity overspilt from a ladle at the back-tilting period of a ladle acted to finish the pouring, and also to give a method to suppress the sloshing(liquid vibration)during back-tilting. By making use of predictive control of flow quantity, a supervisory control system is given to suitably switch without overflow of the fluid in a sprue cup from a level controller to a back-tilting controller with sloshing-suppresion. A Hybrid Shape Approach with a notch-filter under consideraion of the time and the frequency characteristics is applied to suppress the sloshing. The effectiveness of the proposed method is demonstrated through experiments.

An optimum design with sloshing suppression on container transfer control of molten metal using computer fluid dynamics model

This paper presented a control system design method for molten metal's container transfer by using a computer fluid simulator. By means of the computer-aided simulation, sloshing (liquid vibration) phenomena is analyzed and the natural frequency of liquid in a container is identified which plays an important role for controller design. In order to satisfy various control specifications such as sloshing-suppression, transfer time and so on, optimum controller is designed by the Hybrid Shape Approach in consideration of both time and frequency characteristics. By evaluating with computer simulation and experiments, it was found that the proposed method is effective to optimize the process with sloshing suppressed and transfer time shorten. Furthermore, the proposed method is also efficient to reduce the calculation time as compared with conventional ones.

LIQUID LEVEL CONTROL OF AUTOMATIC POURING ROBOT BY TWO-DEGREES-OF-FREEDOM CONTROL

The purpose of this paper is to provide a method to hold the liquid in a sprue cup into the constant level and to suppress sloshing (liquid vibration). This paper uses tilting type automatic pouring robot. A two-degrees-of-freedom control system is used to control the liquid level. This paper presents a series of models representing each part of the pouring process. Through these models, feedforward input can be achieved. Also, to improve the control, two-degrees-of-freedom-control is applied. Liquid vibration inside a ladle after pouring is suppressed by a controller using the Hybrid Shape Approach. As a result, the liquid level in a sprue cap is held to around the setpoint, and sloshing is suppressed. The validity of the proposed control system is demonstrated through experiments.

Sloshing Analysis and Control System Design of Molten Metal Transfer by Using CFD.

In recent years, many liquid container transfer systems used for the transfer of molten metal in the casting and steel industries have been studied. However, there are few studies to show the control system design method for real molten metal transfer although there are many for water, and it is highly demanded to realize the system in real plants. This paper gives the control system design method for molten metal transfer by using fluid behavior simulator, and realizes the molten metal transfer system. In order to design a feedback controller, sloshing phenomenon is analyzed by using Computational Fluid Dynamics (CFD) Model, and Hybrid Shape Approach is applied. The effectiveness of the proposed design method is shown through real experiment with water and the control simulations based on CFD with molten metal.

MOTION CONTROL OF OMNIDIRECTIONAL WHEELCHAIR CONSIDERING PATIENT COMFORT

An omnidirectional wheelchair is highly maneuverable in narrow or crowded areas such as residences, offices and hospitals. In this paper, a novel motion control system for an omnidirectional wheelchair is proposed. In order to ensure a comfortable ride for the patient, the controller is designed using a hybrid shape approach that considers both time and frequency characteristics. The effectiveness of the proposed system is evaluated by the output signal of a sensor attached to the wheelchair and by a descriptive inspection by several users.

Sensor-Less Sway Control of Rotary Crane Considering the Collision Avoidance to the Ground.

In recent years, many rotary crane systems used for factories, construction sites, harbors have been studied. However, there are few studies to show the sensorless sway control and collision avoidance to the ground, although it is highly demanded to realize the system in real plants. In this paper, a Load-horizontal control system with sway-suppression is realized by applying Hybrid shape approach and synchronized control. Furthermore, the robustness against the change in rope length and the sensorless sway control are also realized by applying the Hybrid shape approach. The effectiveness of the proposed system is shown through simulatidns and experiments.