Chiharu Ishii

Robotic Forceps Manipulator With a Novel Bending Mechanism

This paper proposes a new bending technique with a screwdrive mechanism that allows for omnidirectional bending motion by rotating two linkages, each consisting of a right-handed screw, a universal joint, and a left-handed screw. The new screwdrive mechanism, termed double-screw-drive (DSD) mechanism, is utilized in a robotic forceps manipulator for laparoscopic surgery. A robotic forceps manipulator incorporating the DSD mechanism (DSD forceps) can bend without using wires. Without wires, it has high rigidity, and can bend at 90° in any arbitrary direction. In addition, the gripper of the DSD forceps can perform rotational motion, which is achieved by rotating a third linkage in the DSD mechanism. Opening and closing motions of the gripper are attained by wire actuation. Fundamental experiments examining the bending force and the accuracy of the DSD forceps were conducted, and an analysis of the accuracy was performed. Control of the DSD forceps through a teleoperation system was achieved via a joystick-type manipulator. A servo system was constructed for each linkage and the wire actuation mechanism, and tracking control experiments as well as a suturing experiment were conducted. The results of the experiments showed that the required design specifications were fulfilled. Thus, the validity of the DSD forceps was demonstrated.

Lyapunov recursive design of robust adaptive tracking control with L 2-gain performance for electrically-driven robot manipulators

This paper develops a new Lyapunov recursive design for the tracking control problem of rigid-link electrically-driven robot manipulators with uncertainty by taking a tracking performance into account. The tracking performance is evaluated by L 2-gain from a torque level disturbance signal to a penalty signal for the tracking error between outputs of the manipulator and desired trajectories. The novelty of our approach is in the strategy to construct such a Lyapunov function recursively that ensures not only stability of a tracking error system but also an L 2-gain constraint, which provides a closed-form solution for non-linear H

Development of a New Bending Mechanism and Its Application to Robotic Forceps Manipulator

This paper proposes a new bending mechanism with a screw drive mechanism, which enables omni-directional bending motion by rotating two linkages consisted of right-handed screw, universal joint and left-handed screw. We call this mechanism double-screw-drive (DSD) mechanism. DSD mechanism was applied to a robotic forceps manipulator for laparoscopic surgery. In the first prototype, by adding the third linkage to DSD mechanism and rotating this, opening and closing motions of a gripper was attained. In the second prototype, DSD forceps manipulator was enhanced so that its gripper can rotate. This is achieved by rotating the third linkage in DSD mechanism. On the other hand, the opening and closing motions of a gripper is attained by wire-drive. The developed DSD forceps manipulator realizes bending motion without using wires. Therefore, it has high rigidity, and it can bend 90 degrees in arbitrary direction. In order to control the developed DSD robotic forceps manipulator as teleoperation system, joy-stick type manipulator for remote control was built and servo system was constructed for each linkage. Servo experiments show the effectiveness of the constructed control system.

An image conversion algorithm from fish eye image to perspective image for human eyes

In this paper, we consider the omni-directional vision using equidistance projection fish eye lens. The partial domain of an original image in fish eye image is selected, and this is converted to a perspective image for human eyes based on a projection rule of fish eye lens so that it may become the same as a standard image which is obtained by central projection of common lens. However, since this conversion enlarges the original image spatially and is based on discrete data, crevice is generated in the converted image (sparse problem). To solve this problem, interpolation based on an intensity of the image is performed for the crevice in the converted image. This paper provides the experimental results of perspective image conversion for human eyes using the proposed conversion and interpolation methods for both gray-scale and color images, and the adequacy and improving point of the proposed techniques are discussed.

Robot finger design for myoelectric prosthetic hand and recognition of finger motions via surface EMG

In this paper, robot hand design aiming at application to a myoelectric prosthetic hand and recognition of finger operation via surface EMG are discussed. The robot hand with two fingers, thumb and index finger, was built to implement fundamental motions required in daily life, such as grasping and holding. The fingers are driven by the wire actuation system to imitate the humans tendon mechanism. In order to control each finger of the developed myoelectric prosthetic hand independently, using the neural network, identifier which classifies four finger operations, namely flexion and extension of the thumb in metacarpophalangeal (MP) joint and flexion and extension of the index finger in MP joint, was constructed. The recognition of each finger operation was performed using the four patterns of the neural network based identifiers in which the recognition method of finger operations differs each other, and the results were compared.

Development of a New Robotic Forceps Manipulator for Minimally Invasive Surgery and Its Control

This paper proposes a new robotic forceps manipulator for laparoscopic surgery using the double-screw-drive (DSD) mechanism developed by us. DSD mechanism is a link driven mechanism which enables omni-directional bending motion by rotating two linkages consisted of right-handed screw, universal joint and left-handed screw. A novel point of this paper lies in the fact that the DSD robotic forceps manipulator was enhanced so that its gripper can rotate. This is achieved by rotating another linkage in DSD mechanism. On the other hand, the opening and closing motions of a gripper is attained by wire-drive. In order to control the developed multi-DOF robotic forceps manipulator as a master slave manipulator system, joy-stick type master manipulator is also built and servo system is constructed. Bending motion experiments show the effectiveness of the constructed control system

Driving Electric Car by Using EMG Interface

This paper proposes a useful method driving the electric car by using EMG interface, which is used as living body interface. The EMG signal can be measured from all the people easily, even physically handicapped people, elderly and so on. The EMG signals are measured from both hand palms and neck using a simple electrode. In our interface, the effective frequency band of EMG signal is extracted to drive the electric car effectively. The extracted signal is converted to binary signal which drives differential motor. In the experiments that driving the electric car by using the proposed EMG interface, we used the SD method to evaluate of operation feeling and riding comfort. As a result, it is shown that the effective frequency band gives an influence on operation feeling and riding comfort

Robust adaptive tracking control with L/sub 2/-gain disturbance attenuation for electrically-driven robot manipulators

This paper develops a new Lyapunov recursive design for the robust adaptive tracking control problem of rigid-link electrically-driven robot manipulators with uncertainty. The novelty is in the strategy to construct such a Lyapunov function recursively that ensures not only stability of a tracking error system but also an L/sub 2/-gain constraint for the tracking performance.

Walker with hand haptic interface for spatial recognition

This paper presents a user-friendly hand force feedback system to recognize surrounding obstacles around the elderly to making walking safer. The system is implemented on a joystick mounted on a walker. The user is able to recognize the surrounding spatial information from the repulsive force generated as feedback on the joystick. The system is based on the generation of a virtual potential field that corresponds to the distance and direction to the obstacle is employed. Through the experimental results, it is found that the practice time of the user to learn basic operation of the system is sufficiently short. Furthermore, the user feels the sense of security while recognizing the surrounding information through the hand force feedback

Bilateral control for remote controlled robotic forceps system with time varying delay

Recently, development of the surgical support devices with the application of robot technology is in demand. We have developed a multi-DOF robotic forceps manipulator using a novel omnidirectional bending mechanism, and for the developed robotic forceps manipulator, we proposed a passivity based bilateral control that enables motion scaling in both position tracking and force tracking, and guarantees the stability of the teleoperation system in the presence of constant time delay, so far. In this paper, the passivity based bilateral control is extended so as to guarantee the stability of the teleoperation system not only in the presence of the constant time delay but also in the presence of the time varying delay. In order to verify the effectiveness of the proposed control law, experimental works were carried out for the developed robotic forceps teleoperation system.