Masafumi Hamaguchi

Modeling and input shaping control of liquid vibration for an automatic pouring system

This paper presents a modeling and a control of the liquid vibration for an automatic pouring system of tilting-type. Liquid vibrations as caused by the rotation of a tank are analysed by means of a 2-D distributed parameter model and a simplified pendulum-type model. The latter is used for designing the control input which reduces the liquid vibration. Model validity is confirmed by laboratory experiments. A method of preshaping command input is applied for producing the shaped control inputs which reduces the endpoint vibration. Desired control inputs are altered so that the system completes the requested angle for the tank rotation without the residual vibration. Experimental results show that the input shaping method applied for an automatic pouring system is useful to reduce the endpoint residual vibration and also attain the requested motion.

Liquid Container Transfer Considering the Suppression of Sloshing for the Change of Liquid Level

Abstract In this paper, we proposed the liquid container transfer system with the robustness for the change of liquid level. H ∞ control theory has been applied to this system to obtain the robustness for the change of liquid level. Furthermore, a reference trajectory is reasonably determined by an optimization method of Fletcher Reeves combined with a clipping-off technique to suppress the sloshing (liquid vibration). Through simulations and experiments, the effectiveness of the present control system has been demonstrated. And also, the effectiveness has been shown by comparing with such a conventional control method of LQI control with Kalman filter.

Trajectory planning for meal assist robot considering spilling avoidance

In the near future, there will be a significant problem obtaining workers in the fields of welfare and nursing care because of a labor shortage. To solve this problem, many welfare robots, such as an upper extremity motion assistance robot and a meal assistance robot, have been studied. The purpose of this paper is to avoid spilling of the liquid when the spoon is transferred. In order to avoid spilling of the liquid, a spilling model was evaluated by using a CFD simulator. Thus, it was not necessary to build an exact model of the spilling model mechanism. The effectiveness of the proposed control is shown by CFD simulations and experiments.

Sloshing Damping Control in a Cylindrical Container on a Wheeled Mobile Robot Using Dual-Swing Active-Vibration Reduction

This paper proposes a damping control of sloshing in a cylindrical container on a wheeled mobile robot. The container can be independently tilted in the running direction and the orthogonal direction by a dual swing-type active vibration reducer. The mobile robot runs along a curved path on a slope. Sloshing generated by the action of the mobile robot is damped using the vibration reducer. In addition, the vibration reducer can make the container level on the slope. The control system of the vibration reducer is an optimal servo controller with a Kalman filter. The usefulness of proposed damping control system is demonstrated through experiments. Keywords—Sloshing, Active vibration reducer, Wheeled mobile robot, Damping control

TRANSFER CONTROL AND CURVED PATH DESIGN FOR CYLINDRICAL LIQUID CONTAINER

Abstract A spherical pendulum-type model was constructed to represent liquid sloshing in a cylindrical container caused by container transfer along a curved path. The model was used to design a curved path and a transfer control system in consideration of the damping of sloshing in the container. The curvature radius of the curved path and the acceleration of the container were determined using an input shaping method. The effectiveness of the present method was clarified through experiment and simulation.

Damping Path Design for Liquid Container Transferred with Wheeled Mobile Robot along Multiple Turn Sections

Abstract This paper proposes a design method of a damping path for a cylindrical liquid container transferred with a wheeled mobile robot. The damping path is constructed from the acceleration using the principle of an input shaping method. Although a positional error is occurred by using the input shaping method, it is easy to correct the error with the proposed method. The proposed design method can be applied to a complex reference path including multiple turn sections. In addition, a constraint condition of maximum amplitude of sloshing in the container can be taken into consideration. The effectiveness of the proposed method is clarified through simulations and experiments.

Path design and trace control of a wheeled mobile robot to damp liquid sloshing in a cylindrical container

A spherical pendulum-type model is constructed to represent liquid sloshing in a cylindrical container, caused by the motions of a wheeled mobile robot. The model is used to design a path and an acceleration pattern for the robot in consideration of the damping of sloshing in the container. The curvature radius of the path and the acceleration pattern of the robot are determined using an input shaping method. A PD controller is used so that the robot can trace the designed path. The effectiveness of the present method is clarified through experimental results.

Advanced Control of Liquid Container Transfer Considering the Suppression of Liquid Vibration

Abstract The present paper is concerned with advanced control of liquid container transfer paying special attention to high speed transfer and the suppression of sloshing. In order to construct a liquid container transfer system which satisfied requirements for a robustness for the change of liquid level and a reduction in residual vibration, a nominal model was suitably decided and a reference trajectory was reasonably determined by an optimization method. Furthermore, an active control method was presented by adding a rotational motion to suppress excessive sloshing during acceleration or deceleration of the container transfer.

Damping and Transfer Control of Liquid in a Cylindrical Container Using a Wheeled Mobile Robot

A spherical pendulum-type model is constructed to represent liquid sloshing in a cylindrical container, caused by the motions of a wheeled mobile robot (WMR). The model is used to design a path and an acceleration pattern for the WMR in consideration of the damping of sloshing in the container. The curvature radius of the path and the acceleration pattern of the WMR are determined using an input shaping method. A PD controller is used so that the WMR can trace the designed path. Maximum displacement magnitude of the sloshing is considered as a constraint condition in this control transfer system. The effectiveness of the present method is clarified through simulations and experiments. Keywords—Transfer control, Sloshing, Damping control, Wheeled mobile robot, Path design

An Obstacle Avoidance Method for Action Support 7-DOF Manipulators Using Impedance Control

An obstacle avoidance method of action support 7-DOF manipulators is proposed in this paper. The manipulators are controlled with impedance control to follow users motions. 7-DOF manipulators are able to avoid obstacles without changing the orbit of the end-effector because they have kinematic redundancy. A joint rate vector is used to change angular velocity of an arbitrary joint with kinematic redundancy. The priority of avoidance is introduced into the proposed method, so that avoidance motions precede follow motions when obstacles are close to the manipulators. The usefulness of the proposed method is demonstrated through obstacle avoidance simulations and experiments.