In this paper, a model reference input shaping (MRIS) control will be formulated for a luffing dynamics of a rotary crane system with a time-varying rope length. The newly established technique is able to completely suppress the residual vibration for a highly nonlinear time-varying system. The basic idea of the proposed approach is to obtain a reference oscillation from a second-order time-invariant linear system, on which the standard input shaping control is applied. The MRIS control law is then designed to exactly match the real vibration of the system with the reference oscillation. By such a means, an exact zero vibration suppression can be achieved for the actual system. The reference (or unshaped) command is parameterized to cope with control objectives other than the vibration suppression. Simulation results are provided to verify the superiority of the MRIS controller over the standard robust input shaping control method.

We present a flexible ultrasonic motor that generates linear motion as a novel soft actuator. This motor is comprised of a single cube stator with a through-hole, and a flexible coil spring inserted into the hole. The coil spring, which has a diameter of 10 mm and length of 200 mm, is translated by a vibration generated in the stator. A preload between the stator and the coil spring is important for improving the motor performance. The coil spring inserted into the stator hole generates the preload by expanding in a radial direction. We build a prototype flexible ultrasonic motor, and examine its basic performance parameters such as thrust force, velocity, response time, resolution and flexibility. To demonstrate flexibility, we show the stable thrust force and velocity even when the coil spring is bent to a bending radius of 15 mm.

Mobile robot positioning in an indoor environment via fingerprinting technique is made by matching the unknown WiFi data to a spatial WiFi power map database. In past years, this technique has gained reasonable accuracies in the cost of high labor yielded for the database. Thus, automatic database construction by means of interpolating missing data is desired. This paper described a variation of Inverse Distance Weight (IDW) interpolation which is the Modified Shepard's Method (MSM) for our medical-oriented mobile robot - Terapio. By properly selecting the reference locations, we found that this method is better than the conventional IDW method and comparable to the recently popular Kriging interpolation algorithm in an indoor environment by employing the state-of-the-art WKNN positioning algorithm.

We have developed a new type of robot which accompanies the healthcare professionals making medical rounds in patient's bedrooms at hospitals. This novel robot mainly executes two tasks: the carrying armamentarium of round medical supplies and the recording electronic health data on rounds. An omni-directional mobile mechanism and a human tracking control system to follow a specified medical professionals realize smooth transfer movement from the nurses' station to patient's bedroom. Electronic health data on rounds is automatically recorded by using a CCD camera and a voice recorder. When the robot is connected via a cable to a medical data server in nurses' station, the robot transmits the patients' data to the server and receives new patients' information.

Visual and auditory communication over the Internet has enabled communication unlike any humankind has experienced before. However, Internet communication based on haptic interfaces is not yet widespread. This study seeks to allow thousands of people to share the sense of force and enjoy Internet games such as tug-of-war by providing a stabilizing system able to overcome Internet communication delay. First, we derive non-positivity for the multi-coupling physical model. Second, we prove that a closed loop using a phase control filter is stable despite constant communication delay using Integral Quadratic Constraints (IQC). Finally, we validate our proposed system through a series of experiments with 8 clients.

We propose an eye robot system with master-slave control using operator-gaze tracking data, which can produce a high response level such as that of the human eyes. The operators can move a remote robot camera by only moving their eye (master) in front of an eye tracking apparatus and obtain visual information of the environment surrounding the robot's eye (slave). The use of ultrasonic motors has enabled the high responsiveness of the robot eye and the compactness of the robot body. Our graphical user interface (GUI) makes the operation intuitive. We evaluate the robot system from modeling the ultrasonic motor model to the usability of GUI. Finally, the proposed robot system's usability compares well with that of the joystick typically used to operate robots.

In this paper, we develop the operational training system by teaching control input to crane operators. In particular, it is applied to the sway suppression control of load, by utilizing optimal control input. If crane operators can replicate its control input, they can operate crane suppressing the load sway, and hope the advance of training effect. Firstly, we build a shipboard rotary crane simulator, and verify the validity of the training simulator by transfer simulation. Nextly, it presents a sway suppression control method to obtain control input for crane operators, and proposes the training system to teach its control input to operators. Finally, the crane simulator integrates this training system, and the proposed training system verifies the validity by subjects experiments.

This paper describes a robot-mediated information guide system that introduces audio-visual information to users interactively. The developed information guide system is composed of a touch panel interface, a mediator robot and backyard control systems. The touch panel interface functions to display audio-visual contents, while the mediator robot attracts people to this guide system and help user's operation. Many robots in literature are equipped with interactive audio-visual interface, however in most cases the audio-visual interface is a front end of the robot for presentation. We propose a new communication framework in which the robot behaves as a mediator to make a bridge between users and audio-visual interface by generating speeches and gestures. We hypothesize that entrainment of the mediator robot with users and contents could promote user's immersion in the contents. We conducted experiments with the proposed information guide system to examine the effect of robot mediation in a realistic interaction scenario that actually guides city sites for visitors. The developed information guide system was demonstrated in the science museum of the city in May 2014 and will be used for public events in future.

The paper describes audio-visual feedback to assist people's cognitive activities by using a mobile robot. Robot assistance provides promising aid for people in rehabilitation. In literature, physical assistance with mechanical systems such as power-assist limbs and mobile support platforms have been studied well. On the other hand, cognitive assistance also plays an important role in rehabilitation especially for motor recognition. Motor recognition of own actions however can be difficult for patients who hold cognitive disorders. We propose a novel robot platform for cognitive assistance that gives effective reference of actions. Lucia, a cognitive assistant robot is capable of interacting with people by using pattern projection and sound generation based on recognition of people's posture and movements. In this paper we will define a framework of cognitive assistance and then detail the implementation of the robot and its control system. In experiments we evaluated effect of audio-visual feedback for improvement in motor control. The experimental results suggested that audio-visual feedback of own actions positively affected to improve the success rate of the task movements.

This paper is concerned with an advanced attitude control of the vehicle body in the parallel two-wheel vehicle with underslung vehicle body. Since the parallel two-wheel vehicle has large wheels with its diameter of 1.05m, and the battery, the actuators and the controller are placed on the lower position in the vehicle body, the gravity center of the vehicle body with a passenger can be assigned at the lower position than the wheel axis. Therefore, the vehicle has a pendular structure that enables the vehicle body with the passenger to always maintain the stable posture, even if the vehicle is in the power-off or control-off condition. In order to suppress the sway of the vehicle body on the pitch axis while driving the vehicle, the attitude control system using an active mass system is constructed into the vehicle body. However, the behavior of the vehicle body with the passenger differs depending on person. In this study, a design method for the attitude control system with applicability to various passengers is proposed. The behavior of the vehicle body is related strongly with the passenger's properties. And, the control system using the active mass system is designed by a Backstepping Method. The robust control parameters for suppressing the behavior of the vehicle body associated with the passenger's properties is clarified in this study. The effectiveness of the proposed attitude control system with the active mass system is verified by the experiments using the parallel two-wheel vehicle with underslung vehicle body.

This paper presents a tele-control system comprised of a robot hand/arm and an operator. In our system, the angle of the finger of the robot hand is controlled according to the angle of the operator's finger, and the position of the robot arm is controlled according to the position of the operator's arm. Simultaneously, the operator feels the environmental force as detected by the touch sensor attached to the robot hand, resulting in so-called bilateral master/slave control. To date, there have been a few studies of bilateral master/slave systems that use a multi-fingered humanoid robot hand in communication networks with delay caused by physical distance. The purpose of our study was to achieve tele-operation with bilateral master/slave control between the operator's hand/arm and the multi-fingered humanoid robot hand/arm using the Internet with delay caused by distance. For our experiment, the operator was in the USA, and the multi-fingered humanoid robot hand/arm and object were in Japan. Using our system, the operator could successfully grasp and move an object while he felt the reaction force from the object. This technology can applicable to tele-operation such as feeling the hardness and weight of the stone which exist in the moon, on the ground etc.

We demonstrate a virtual face of a robot with minimum humanity. The name of the robot is “shugo-robot”, which is after “shugo-rei (guardian spirit)“. The shugo-robot follows her/his master by using laser sensors, and takes greeting behaviors by gazing to master's friend and others. Thus, he/she is a communication agent on behalf of master. The head part of the robot has a camera, and finds human faces. Then, the robot's face gazes at a person nearest to the robot. This behavior makes users to believe the robot has an intention to communicate with them. The robot makes blinking at random timings to show the robot is alive, and several facial expressions to show her/his feelings.

This paper presents a tele-control system constructed by a robot hand/arm and operator. The angle of the robot hand is controlled by the angle of the operator's finger, and the operator feels the environmental force, as detected by the touch sensor of the robot hand, constituting so-called bilateral master/slave control. The position of the robot arm is controlled by the position of the operator's arm.

In this paper, a power-assisted attitude control system consisting of parallel wires is proposed. This system controls the attitude of an object, thus reducing the burden on the operator and allowing direct manipulation. In our previous research, a power-assisted control system for an overhead crane was proposed. Operators could move a heavy object freely in horizontal and vertical directions and adjust one-degree-of freedom (1-DOF) attitude by inputting a slight force grasping the object directly, that meant the operator did not feel any sensors. Our newly proposed equipment consists of an overhead crane and two linear cylinders. A power-assisted 2-DOF attitude control algorithm that controls the length of the cylinders and hoisting motion of the crane synchronously is proposed, and the effectiveness of the system is demonstrated in some experiments.

Holonomic omnidirectional mobile robots are useful because of their high level of mobility in narrow or crowded areas, and omnidirectional robots equipped with normal tires are desired for their ability to surmount difference in level as well as their vibration suppression and ride comfort. A caster-drive mechanism using normal tires has been developed to realize a holonomic omnidiredctional robot, but some problems has remain. Here we describe effective systems to control the caster-drive wheels of an omnidirectional mobile robot. We propose a Differential-Drive Steering System (DDSS) using differential gearing to improve the operation ratio of motors. The DDSS generates driving and steering torque effectively from two motors. Simulation and experimental results show that the proposed system is effective for holonomic omnidirectional mobile robots.

Transfer of container filled with liquid may generate sloshing, considered an undesirable effect in many systems. This research explores the use of input shaping technique to suppress sloshing on transfer of liquid container using multi-joint robot arm. By input shaping principle, acceleration command is shaped using two impulses in such a way to cancel each other's response. Position trajectory is then translated as joint angles trajectory, which is then fed to Mitsubishi PA10-7C robot arm. Simple pendulum model with damping element is applied to analyze sloshing phenomena. Experimental results show that the employed input shaping technique reduces sloshing during and after container transfer.

This paper presents intelligent control of power assist system considering skill level of operators for wheelchair. In this paper, operability and anti-fluctuation running against the fluctuation of human force added to the handle by operator are progressed by the proposed auto-tuning system of power-assist controller. A method to estimate the operator's skill level and appropriately adjust the parameters of power-assist controller is presented by applying Fuzzy reasoning method. The effectiveness of the proposed method is demonstrated through experiments of OMW wheelchair.

This paper gives an advanced driving control system that considers sway suppression of a passenger's posture in an electrical wheelchair. We proposed a passenger model that considers the passenger's physical frame and seating condition. The passenger's seating condition is classified as upright, standard, or round-shouldered posture. The sway of a passenger with round-shouldered posture is smaller than that of a passenger with upright posture, and they can be represented by the proposed model. To suppress the sway of a wheelchair passenger's posture, the wheelchair driving pattern is optimized using the proposed passenger's posture model. The comfort of the passenger with respect to the proposed wheelchair driving is evaluated through experiments.

In order to make haptic feedback in teleoperation rehabilitation robot system or to assist the object's movement, recognition the intended movement of an object is required. In this paper, we establish the relation between the electromyography (EMG) signal of some specified hu.man arm's muscles and the moment of corresponding arm's joints. The model and the parameter calibration process are simple to put in to practice. Experiments showed that by using the proposed EMG-moment model, it is possible to predict the moment of the shoulder and elbow joints from the processed EMG signals of specified muscles.

This paper presents a tele-control system constructed from a multi-fingered robot hand and operator. The angle of the robot hand is controlled by the angle of the operator’s finger, and the operator feels the environmental force, as detected by the robot hand, constituting so-called bilateral master/slave control.

This paper proposes an intelligent massage control system by using multi-fingered robot hand with hybrid impedance control, which is able to create the movement and the force of robot such as the human's massage. Therefore, the various massage points, such as the change of the stiffness of human skin muscle, can be controlled by using impedance control method. The hybrid impedance control is comprised of the two methods of the position-based and the force-based impedance control were applied. The position-based impedance control is used to control the lateral position of massage on the human skin muscle. On the other hand, the force-based impedance control is used to control the force of the vertical direction on human skin muscle. This paper also gives the identification of human skin muscle through robot perception of impedance to decide the parameter of impedance controller. The control strategy using impedance control to implement an adaptive control system is presented, when human condition is changed with soft and hard skin muscle. Effectiveness of massage control system by using multi- fingered robot hand with hybrid impedance control is demonstrator through actual massage experiments of pushing and rubbing motion.

This paper proposes an intelligent massage control system by using multi-fingered robot hand with hybrid impedance and force control, which is able to create the movement and force of robot to behave as similar as the human’s massage. Therefore, the various massage points, such as the changing of hardness and softness of human skin muscle condition, can be appropriately controlled by using hybrid impedance and force control method. The impedance control is used to control the lateral position of massage on the human skin muscle. The perpendicular direction one, while force control is carried out for the vertical direction on human skin muscle. This paper also gives a modeling of human skin muscle through robot perception of impedance to decide the parameter of impedance controller. The control strategy using a hybrid impedance and force control to implement an adaptive control system is presented, when human condition is changed with soft and hard skin muscle. For the robot fingertip force, PI servo compensation is used together with impedance control. Based on using both impedance and PI servo compensation, the effectiveness of the massage position and force control is shown through actual massage motion experiments.

In this paper, a vertical power-assisted crane system is proposed. The purpose of this research is to develop a crane system which reduces the operator's burden by power-assisted functions and facilitates the intuitive operation of a heavy object by direct manual manipulation. First, the structure of this system is described, and an analytical optimal controller is designed to stabilize the system under the model uncertainty and to optimize response. Second, "the limit-cycle problem" when an object contacts the ground is pointed out, and the condition for the attenuation of the limit-cycle is discussed. Finally, the usefulness of the proposed controller is demonstrated by an actual power-assisted crane system

In this paper, riding comfort of an omnidirectional wheelchair (OMW) driven by joystick is studied for the case when OMW moves in X direction, Y direction, or in a slanting direction. In order to achieve the comfort driving specific spectrum elements such as natural frequency of OMW and discomfort frequency of human organs are suppressed. In order to evaluate the comfort, a human model which considers human upper body composed of two parts: torso and head, has been developed and used in order to test the effectiveness of the proposed approach. Experimental results of velocity control are shown.

The purpose of this paper is to explore the development of a semi-automatic obstacle avoidance control system that combines manual instructions from an operator with the automatic control of a machine. First, in order to obtain operational support, we employed a special joystick system which provided suggestive information to a crane operator via haptic feedback. The information imparted included such factors as the application of impedance control, gravity compensation, and restriction on the crane's velocity. Second, an integrated system comprised of a restriction system for rotational angle and boom-luffing angle, as well as an obstacle avoidance system was built. Finally, the effectiveness of the proposed obstacle avoidance control system using haptic control was validated through experiments, testing whether or not the present system could transfer a load easily and safely to any target position without colliding with obstacle.

An omni-directional wheelchair is highly maneuverable in narrow or crowded areas such as residences, offices and hospitals. However, with the increase in the degrees of freedom accompanying omni-directional wheelchairs, it has become more important than in the past to develop a smooth and vibrationless motion control system. This paper presents a novel motion control method for an omni-directional wheelchair considering the suppression of vibration of both the wheelchair and the user. In the proposed control system, the vibration of the wheelchair is suppressed by notching the frequency characteristics at the natural frequency of both the wheelchair and human's organs. The designed controller satisfies various control specifications such as settling time and stability by using feedback from only the wheelchair's position data. The effectiveness of the proposed system is evaluated by the output signal of a sensor attached to the wheelchair and by a descriptive inspection of several users.

The present paper gives a haptic feedback control of a holonomic omni-directional mobile wheelchair (OMW) with a haptic joystick for the operation of disable people or elderly people considering not only the navigation task but also user's comfort and safety. In the present research a haptic joystick was designed and applied with being maneuverable for users and free of joystick's vibrations. If an obstacle is detected in the direction of movement, the impedance of the joystick in this direction is changed. Namely, the closer the obstacle is the bigger the impedance value becomes. By this function, users spontaneously understand that they are in risk of obstacle collision and then users can change the direction of movement, by their decision, in order to avoid it. Furthermore, for the command input by human joystick operation, velocity control of OMW is executed by means of frequency shaped control to achieve the comfort drive for users. The proposed approach is thought to be reasonable as a man-machine existing control system.

In this paper, a novel power assist system for the attendant of an omni-directional transport wheelchair is proposed. The input force of the attendant is measured using a force sensor attached to the handle of the wheelchair. The desired motion of the wheelchair is estimated from the output signal of the force sensor using fuzzy reasoning. Then, it is transmitted to four motors of the wheelchair to make it move toward the desired direction. The effectiveness of the proposed method is examined by simulations and experiments.

This paper introduces a system of advanced control of the automatic pouring process, including the control of liquid level in the sprue cup, the flow control as the liquid is poured into a mold and sloshing (liquid vibration) suppression in the ladle. Through the pouring process model built in this paper, we calculated a forward tilting control input to hold the liquid in the sprue cup at a constant level. A backward tilting input is obtained by means of the Hybrid Shape Approach applied to suppress the slosh after backward tilting. We also designed a model by which supervisory control can take into account the After-Flow that occurs when switching the forward tilting input to the backward tilting input, and thus achieve the accurate poured quantity. The validity of the proposed total control system was demonstrated through experiments.

This paper presents a massage motion control system comprised of position control and force control in a multi-fingered robot hand. By making use of an algorithm which converted the desired fingertip trajectory into the desired angle of links in each finger by means of inverse kinematics, the finger position control from the initial position of the multi-fingered robot hand to a target position of the objects for massage was achieved. Its controller was used until the robot hand contacted the objects for massage. After contact was made, the fingertip position control was switched to a force control position needed to apply pressure for the massage. The fingertip forces exerted by an expert human therapist was measured using sheet distribution pressure sensors, and the data obtained was recorded in a computer. After the measurements were taken, the human expert's fingertip force was reproduced by the robot hand. The fingertip force of the robot hand was controlled using feedback obtained with a 6-axis force sensor. To make the force of each fingertip of the four-fingered robot hand track to the fingertip force exerted by the expert human massage therapist, PI servo compensation and a Jacobian matrix were really applied for the human's shoulder. Through simulation and experiments, the usefulness of the proposed control systems was demonstrated.

An omnidirectional wheelchair is highly maneuverable in narrow or crowded areas such as residences, offices and hospitals. A semi-autonomous control method for omnidirectional wheelchairs is proposed. In addition to allowing the normal joystick commands of the wheelchair operator, this method provides a collision avoidance function using external sensors. The proposed method does not employ unexpected autonomous movements conflicting with the operator's joystick commands, because this tends to create discomfort for users and can be dangerous for infirm patients. Instead, the proposed method merely alerts the operator to the presence of an obstacle; this is accomplished by changing the impedance of the joystick essentially creating resistance against moving the joystick in the dangerous. direction. The wheelchair's motion remains controlled only by the operator's joystick commands, while a collision is avoided successfully. The effectiveness of the proposed method is shown by experiments with an onmidirectional wheelchair.

In practical industries, overhead traveling cranes are usually manipulated by a human operator. The transfer object can be freely moved in three-dimensional space by the human operator for various tasks. Although manipulation for the moving direction of a crane is easy, the crane's operation without vibration of a load is difficult for unskilled operators, and therefore swinging of the object occurs and residual vibration is generated after the transfer object reaches a goal point. Therefore, a semi-automatic control system is proposed in terms of obstacle avoidance by manual operation by human operator and feedback control for suppression of swing by automatic controller. Further, in order to heighten safety and prevent human error, the command input to avoid obstacles and go towards a goal is generated by the fusion of human command using joystick and potential information using diffusion equation based on the known environment map. Position and vibration control of a crane are carried out by a fixed-pole controller for the command input (stated previously). The usefulness of the proposed method is demonstrated through simulation and experimental studies.