High speed cameras have the ability to detect luminance variation due to the alternating current of illuminations. On the basis of the luminance variation, this paper proposes a method to estimate an image of when one of the illuminations is nonluminous. If the nonluminous illumination is the source of specular reflection, the estimated image only includes diffuse reflection components of other illuminations. Experimental results in various conditions show that specular reflection components are eliminated without the displacement of a camera or an illumination.

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This paper presents a novel flow control method using a PI controller for servo control over networks. The UDP is known to be effective for motion control systems over networks such as bilateral teleoperation. However, UDP does not have a mechanism for congestion avoidance. The congestion, which causes large communication delay, jitter, and packet loss, deteriorates the performance and stability of control systems over networks. To avoid this congestion, a novel flow control method, which adjusts a packet-sending period in real time, is proposed. The validity of the proposed method is shown by simulation and experimental results.

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A final-state control method has been proposed as a feedforward control method for mechanical systems having vibration modes at high frequencies. Frequency components of the feedforward input are reduced at the desired frequency points by suppressing the residual vibration, thereby achieving high-speed positioning. However, a large memory size is required in order to store the feedforward input data.
This paper proposes a final-state control method in which the feedforward input is generated by a sampled-data polynomial. The required memory size is drastically reduced since only the coefficients of the polynomial are to be stored. The effectiveness of the proposed method is evaluated by applying it to the HDD benchmark problem.

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This paper proposes a design method of zero-moment point (ZMP) disturbance observer for walking stabilization of biped robots. A parameter design method for the filter required in the ZMP disturbance observer is proposed for performance improvement, and a variable compliance controller is introduced for impact reduction during landing. The validity of the proposed method was confirmed by simulations and experiments.

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The authors have developed “haptic armor”, a whole-body haptic sensor that has an ability to estimate contact position. Although it is developed for safety assurance of robots in human environment, it can also be used as an interface. This paper proposes a command recognition method based on finger trace information. This paper also discusses some technical issues for improving recognition accuracy of this system.

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In this paper, we propose position/force hybrid control in oblique coordinate. Position and force tasks are transformed by “task Jacobian matrix” and the dynamic properties are given by “task mass matrix”. Bilateral control between different degrees-of-freedom systems is implemented, and its validity is experimentally verified.

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This paper presents a vibration suppression control by a load acceleration feedback control scheme that takes into account the interference force between two table drive systems on a common machine stand. In the proposed control, a two-degrees-of-freedom (2DOF) controller is designed to achieve single-input two-output control, where a load acceleration control loop using the acceleration signal and a conventional motor position control loop are realized. In addition, resonant filters are used in the 2DOF controller to suppress the effects of the interference on the positioning performance. The proposed approach has been verified by experiments by using a prototype of table drive positioning device.

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Force interference between multiple positioning devices with arbitrary motion profiles may deteriorate positioning performance. In this study, feedforward compensation based on an interference model of table drive systems was applied to suppress the effects of interference on positioning. The interference model was experimentally identified on the basis of frequency responses by a sinusoidal sweep method.
The proposed feedforward compensation for the interference has been verified by using a prototype that consists of two table systems on a common machine stand.

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In this paper we propose a control method that compensates for the following two factors in network-based control systems: one is time-varying delay on network communication and the other is modeling error due to uncertainty of the plant. For the time-varying delay, we essentially deal with it with the accurate modeling by measuring the individual time delay and utilize it for model based compensator. Because the time delay on the network is not completely uncertain but measurable value. By measuring the values and using them for the control, the performance of the system can be improved. On the other hand, the accurate modeling of the plant is very difficult and the property of the actual plant may because of the variation of loads or with age deterioration; thus the modeling error is inevitable. The modeling error appears in the form of a loop gain variation that composes the closed loop together with the phase delay caused by the time delay. Therefore, we propose a compensator whose design is based on the robust control theory for the uncertainty of the plant.

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This paper proposes an image processing system for counting people at an elevator lobby viewed from an upper oblique angle. The method is based on two assumptions: heads of people exist around the upper edge of the images of moving objects; and shape of the head is circular. This paper shows that the method based on these assumptions acquires high recognition rate and high reliability in an elevator lobby with many overlapped images of people.

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Recently, the demand for the practical use of service robots has risen significantly because of acceleration of demographic aging, and a humanoid robot is one of the promising form factors of service robots. When a humanoid robot is used by a human in a real environment, the robot needs to be designed by taking into account the various external forces that act on the robot. Thus far, most of the walking humanoid robots have been mainly controlled by the conventional ZMP method to maintain a stable walking posture. However, the conventional ZMP method can not be used to handle the various external forces that act on the upper part of the humanoid robot body. To overcome these problems, in this paper, we propose a novel control method, which we called 3DZMP and pZMP, for a humanoid robot to react to the external force on the upper part of the body. The 3DZMP is defined as the point in three-dimensional space at which the moment about all axes is zero. 3DZMP can prevent the rotation of a humanoid robot. The pZMP is defined as the point corresponding to the orthographic projection of the 3DZMP on a plane. pZMP is used to evaluate the stability of 3DZMP. We implemented the proposed method on a prototype robot and verified that the robot gained the capability to react to external forces that could not be handled by the conventional ZMP method.

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Real-world haptics is being studied not only for improving feedback on real-world haptic information in teleoperation but also for developing key technologies for future human support. For the remote operating of systems at distant places, haptic information is required in addition to visual information. The haptic information around a work environment can be the floor reaction force, which can be obtained using a movement-type haptic device. The floor reaction force from the environment that the mobile haptic device touches is fed back accurately to the operator.
First, this paper proposes a general force-reflecting-type multilateral control. Second, this paper extends the control to feedback control of the floor reaction force by using force-reflecting-type multilateral control and a novel haptic device employing a biped robot with a slave system. The position response of a master system is transformed to a leg tip position command for the biped-type haptic device. In addition, the floor reaction force determined by the biped-type haptic device is fed back to the master system. The proposed method can determine the force feedback to the sole of the foot, which is not possible with a conventional stationary system. As a result, the floor reaction force from a large area can be obtained, and the operability of the control system is improved by using the proposed system.

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Recently, there has been extensive development in remote communication technologies such as telephone, radio, and television. Haptic information is studied as the third type of multimedia information. Real-world haptics is getting attention not only for the feedback of real-world haptic information in teleoperation but also as the key technology for future human support. Most of the objects of study in haptics are stationary. Therefore, the moving range of such haptic systems is limited.
This paper proposes a novel haptic device that receives force feedback of walking motion from a remote environment and manipulates remote system. Thus, its moving range is unrestricted. To drive this haptic system, the paper also proposes asynchronous multilateral control. By using this control, an operator can operate the remote system without changing his/her position. The proposed haptic system is expected to act as an effective interface for virtual reality applications and teleoperation.

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This paper describes an approach to motion stabilization by using laser distance sensors for biped robots with flexible ankle joints. To avoid the vibrated zero moment point (ZMP) behavior caused by mechanical resonance, a vibration control method is proposed in the paper. In our approach, the deformation of the ankle joint is measured by using laser distance sensors, and the detected deformation is translated into the equivalent reaction force at the center of gravity. The feedback of the reaction force enables the stabilization of the walking motion in a manner similar to resonance ratio control. The validity of the proposed method is evaluated by several experimental results.

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This paper proposes a new motion control strategy for industrial robots. It is important to achieve rapid and accurate control of the motion of industrial robots. However, industrial robots often have vibration which is caused by the resonant frequency and nonlinear interference force from various joints of the robot. In this case, the notch filtering method for generating a reference is useful for suppressing the resonant phenomenon. However, the path tracking error of the robot motion increases because phase delay becomes large by using the notch filter.
In order to overcome these problems, this paper proposes a zero-phase notch filter without phase delay for fast path tracking. Moreover, this paper proposes a fast position control method based on D-PD control with dynamic feed-forward compensation. Using these proposed strategies, this paper achieves fast and accurate robot motion control without vibration and overshoot.

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A vision system with a dominant eye, which is inspired by the function of human vision, is demonstrated as an artificial and remote vision system. This paper focuses on a remote operation in which an operator wearing a 3D head mount display (HMD) controls a stereo camera head in order to acquire visual information, which was focused upon, from a work space. A manual operation method is proposed and implemented in order to display appropriate 3D images to the operator.

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In this paper, a sensorless wire rope tension control is introduced and analyzed to implement a wire-based robot with twin direct-drive motor system. Two of the same direct-drive motors are required and connected by wire rope mechanism. In the controller design, dual disturbance observers with respect to two control modes, namely the common mode and the differential mode are designed and applied for control of motion and wire rope tension. The wire rope tension in the common mode is controlled in order to regulate the mechanical bandwidth of the system. From the identification results, the high-tension of wire rope system is obtained a high mechanical bandwidth in the robot systems. The disturbance observer-based eliminates the need for the tension sensors, and may also be used to achieve the precise velocity and position control with the vibration-free performance in the differential mode. The effectiveness of the proposed method is verified by experimental results. It is shown that the high frequency responses are obtained by using high-tension of wire rope. The control performance may improve during the robot operation and, therefore, it is useful to compensate for the vibration effect.

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