Yoshiyuki Noda

FALLING POSITION CONTROL OF OUTFLOW LIQUID FOR AUTOMATIC POURING SYSTEM WITH TILTING-TYPE LADLE

Abstract This paper presents advanced control for automatic pouring system with the tilting-type ladle in casting industry. The falling position control of outflow liquid poured from the ladle is proposed in the paper. The mathematical model of the falling position is derived from the shape of the ladle and the pouring conditions. The falling position control system is constructed by using the model from the control input applied to the motor to the falling position. In order to verify the effectiveness of the proposed control system, the control system was applied to the automatic pouring system which was tested by simulation studies.

Sloshing suppression control during liquid container transfer involving dynamic tilting using Wigner distribution analysis

This paper addresses concerned with the advanced control of the transfer of liquid in a container, with special consideration given to transfer involving liquid container with dynamic tilting as well as the suppression of sloshing (liquid vibration) while maintaining a high transfer speed for the container. In the transfer with dynamic (continuous) tilting, the sloshings natural frequency is varied with the change of tilting angle. In order to suppress the sloshing caused by such transfer, a new controller design method is proposed. First, the varying natural frequency is estimated using the Wigner distribution. Then, in order to suppress the sloshing, the position control is designed using the hybrid shape approach utilizing a time-varying notch filter. The effectiveness of the proposed control system is shown experimentally in a liquid container transfer system.

Feedforward Control Considering Input and States Constraints with Eliminating Residual Vibration

This paper presents a design method for damping feedforward control input that inhibits residual vibration while assuring states constraints, for systems accompanied by fluctuations of the resonance frequency. It is realized by reducing the problem of minimizing the tracking error and the energy of the desired overall frequency band to a quadratic programming problem. Compared to conventional techniques, this technique can hold at all times the residual vibration to an extremely low value no matter how the resonance frequency of the plant may fluctuate within the range of the estimate. In addition, the computation volume is relatively small, so it is possible to deal adequately with practical on-line plants. The effectiveness of this technique was demonstrated by an experiment with a liquid transfer system.

Wheelchair Driving Control with Passenger's Posture Behavior Suppression and Evaluation of Comfort of Ride by Emotional Sweating

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 that uses a backrest in the wheelchair has been constructed and a driving pattern that suppresses a passenger’s posture behavior has been developed using optimization methods. Then, the quality of the ride while a passenger drives 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 previous posture behavior and improves the comfort of wheelchair driving.

Optimal Sequence Control of Automatic Pouring System in Press Casting Process by using Greensand Mold

In the present paper, the optimal sequence control to the tilting-ladle type automatic pouring system in the press casting process is proposed. At first, dynamics of the pouring process is modeled by using mass balance and Bernoullis theorem. By using the model, a conventional sequence control in the automatic pouring system is analyzed. Then, in order to suppress the splash of molten metal during the pouring motion, the pouring pattern which has two steps flow rate is used to reference pouring pattern. In order to perform the pouring motion at short times and reduce the error between reference flow rate and real one, the sequence control parameters are then optimized. The effectiveness of the present system is demonstrated through simulations and experiments by real plant

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

Abstract 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.

Operator assistance system of rotary crane by gain-scheduled H ∞ controller with reference governor

This paper describes control of a rotary crane for the change of rope length. The load position and its sway control is designed by using the gain-scheduled H∞ controller. Furthermore, reference governor with the maximum constrained positively invariant (CPI) set is proposed for the time-variant system to give the reference input satisfying the input constraints and sway suppression.

A mechatronics vision for smart wheelchairs

Advances in rehabilitation and assistive technologies can be seen today. Nevertheless, there still remains an area that ought to be examined more seriously from an economic standpoint. We call this area a mechatronics support service, which lies as a support technology centered on mechanics, electronics, and computing. This paper explores key issues in the establishment of a mechatronics service framework that hosts micro and macro control for the smooth navigation of mobile wheelchairs and surrounding information systems. Specifically, we propose a systems architecture that facilitates terrain surveillance and intelligence gathering through laser sensor implanted in the wheelchair, for the purpose to identify unusual patterns of movement to predict accidents. We also emphasize the importance of information technology which is a key for providing flexible transportation services for those in need of wheelchairs. The significance of this research for the longer-term goals lies in its implications for adaptation of our intelligent model into the future welfare activities. Foundations for and mechatronics specifications for micro and macro-control architecture are presented.

Driving control considering torsional vibration suppression in a stepping motor with a full-step drive

This paper presents modeling of a stepping motor with a full-step drive and design on the timing of the pulse inputs for the suppression control of vibration. When the stepping motor is shifted to the excitation phase, a torsional vibration occurs at the shaft part connecting to the motor due to an inertia load. Therefore, in the present study, a motor model considering a torsional vibration is designed and built. The validity of the proposed model is verified by comparing the model considering a torsional vibration with the conventional model without such a consideration. The timing of the pulse inputs to drive the motor is then optimized to suppress residual vibrations and also to shorten the settling time. Finally, the effectiveness of the proposed method is demonstrated through experiments.

Weight control of pouring liquid by automatic pouring robot

Abstract This paper gives an advanced control system in tilting-ladle type automatic pouring robot. In a pouring process, it has been required that molten metal is poured precisely and quickly into the mold for improving the productivity and saving energy. Therefore, the pouring liquid weight control, which the weight of the pouring liquid is controlled precisely to the target weight, is proposed in this paper. In the proposed control system, the state of pouring process are estimated using Extended Kalman Filter, and the timing of tilting the ladle back is determined by the predictive equation to the pouring liquid. The effectiveness of the proposed pouring liquid weight control is demonstrated through the experiments using water to generalize the design procedure of pouring liquid weight control.