We propose an easy method that can automatically tune impedance control parameters in a short time. The proposed method tunes damping parameters of impedance control so that response to force step reference can be settled at the shortest time while getting the grasped work piece contacted repeatedly. The proposed method can quickly search optimal damping value because it tunes coarsely to a region including optimal value by vibration count and then it fine-tunes according to transition of the settling time. Experimental results show that tuning is done in a short time under various conditions. In addition, insertion task is done in the shortest time with the tuned parameters.
The rest room in the highway service area occupies a large space and requires cleaning at regular intervals throughout the day, 24 hours. However, it is becoming increasingly difficult to find required number of cleaning staffs, particularly for cleaning during the night. Moreover, today's rest room is more sophisticated and has many more facilities than before, and demand for higher and better cleaning quality is strong. In this paper, we present a small cleaning robot for the rest room. The robot automatically cleans the floor by two cleaning methods: dry, vacuum cleaning for small trash, dust, and hairs, and wet, mopping cleaning for dirt and stains. The robot was tested in the actual rest room environment, and results show that it was effecitive and efficient for automating cleaning tasks in the rest room.
Growing garden products involves a lot of work, such as harvesting, which is difficult to mechanize. Garden product crops require longer working hour compared with rice. We are developing a robot performing soil sterilization aimed at preventing repeated cultivation disorder. This robot is a medicinal solution injection robot injecting chloropicrin to use for soil sterilization automatically. The developed robot is driven by oil pressure actuators, runs on crawlers, with an chemical injector mounted in front of the robot. The robot is equipped with a triangular surveying sensor. The robot covers entire working soil area with a combination of straight lines and arcs along which the position and orientation of the robot is compensated by the output from the sensor. Experiments were conducted to demonstrate that the robot can navigate on the uneven and soft terrain within required position errors.
A novel climbing robots with the use its own weight is presented. The climbing method is similar to climbing approach of timber jacks in Japan. Main features are that the climbing robot driven by servomotors with worm gear can rest on a tree by using own weight without any energy and move up and down quickly. To realize the method, position of center of mass of the pruning robot is located outside of tree. A basic mechanism analysis for avoiding falling down from a cylinder is presented. Moreover, it is shown experimentally that an experimental climbing robot equipped four active wheels can move up and down a tree by the proposed climbing method.
This paper proposes the concept of a novel multi-wheel stair-climbing wheelchair. The necessity for mobility aid technology for elderly and handicapped people that has ``minimal invasiveness for use in an historical environment'' are described. With this goal in mind, a prototype of a novel wheelchair having a stair-climbing function resulting from transformable wheeled four-bar linkages is proposed, and the principle of operation, mechanism design, kinematics, statics and basic performance confirmed through a experiment are illustrated in this paper.
Wearable robots that operate with the wearer's intention to augment muscle strength are called “power suits” or “power assists.” They are expected to play important roles in forthcoming aging society. In such robots, force sensitivity is a vital functionality in order to maintain comfort and safety. The objective of this paper is to develop a power assist device for daily use of elderly with comfort, safety, and reliability. We employ a variation of hydraulic system called electro-hydrostatic actuator to realize intrinsic backdrivability and high mechanical strength. The combination of a low impedance controller that actively enhances backdrivability and a sensitivity function maximization controller are used for power augmentation, which does not require unstable biological signal measurement. A power assist device for knee torque augmentation was developed; it is intended to support the large torque requirement, and to prevent knee buckling that leads to serious injuries.
Colonoscopy is an important medical action to detect disorders like colon cancer. However generally it is difficult to insert a scope into the colon, because the colon is flexible and complex shape. This study aims at development of an actuator which can add propelling ability to a colonoscope. We focus on rubber pneumatic actuators, because advantages of them, for example, high compliance, low cost, water proof, and so on, agree with the required properties of medical devices. In this paper, we design a novel rubber actuator consisting of three air chambers by nonlinear FEM (finite element method) and fabricate the actuator employing the design by extrusion molding method. Basic characteristics of the actuator are clarified by a motion capture system, and functional motion leading assisting colonoscope insertion is observed. Actually using dummy endoscope, transportation ability by the actuators is confirmed experimentally and insertion experiments into a large intestine phantom are conducted.
One of the important tasks required for sonographers is an accurate positioning of ultrasound probe. Especially, the measurement of the diameter of the blood vessel is affected by the positioning error of the probe. For this purpose, we have been developing a robot system for the medical ultrasound diagnosis, which composed of a 6-DOFs probe manipulator and supporting arm. In this paper, we present an implementation of fully automated positioning algorithm of the ultrasound probe on the carotid artery, by means of image feedback. A probe holding robot firstly detects the patient skin, then scans and detects the longitudinal section of the carotid artery, guide the probe towards the position where the tissue layers of the artery walls are most clearly observed. Furthermore, a new method of the visual servoing for tracking the out-of-plane motion for the medical ultrasound is presented. Automated positioning algorithm is tested in eleven volunteers and the results show that the system successfully completed the task in 91% of the trials. Visual servoing algorithm is also tested and the experimental results show its effectiveness.
We have developed a support system using our ultrasound diagnosis robot, which is able to support manual handling of ultrasound probe in echography to alleviate fatigue of physician. This system realizes a coordinated motion according to the motion of the probe, which is held by the robot and is moved by a physician. We have established four kinds of situations, which are initial fixation, coordinate motions with/without contact on the body surface, and automatic chase motion of an internal organ. The system recognizes when the physician grasps the ultrasound probe by 6-axis force sensor and touches it on body surface by processing echograms. Not only unskilled examiners but also a professional sonographer have evaluated the performance of the system after elucidating multiple parameters for compliance control and self-weight compensation of the probe. As the results, this system has the potential to be able to support advanced diagnosis for conventional echography.
Multi-beam optical tweezers is important technique to manipulate multiple small objects. Computer Generated Hologram (CGH) is one of the techniques and it can trap more than 200 objects in three dimensions. For dexterous micromanipulation, it is useful to apply teleoperation into optical tweezers. In this research, we designed the optical system and control system of CGH Optical Tweezers (HOT) synthetically. For optical design, we considered workspace and positioning resolution. For control design, we applied with unilateral master slave control for teleoperation. For online generation of hologram, we developed GCH generator applied with General-purpose GPU acceleration which extremely improved the speed of hologram generation with parallel processing. The built system accomplished generation of 100 beams and trapping of 25 polystyrene beads for demonstration. For full automatic control, we applied stability control theory to the multi-beam control system and evaluated the effectiveness with experiment of trajectory control. Then we demonstrated teleoperation. As the result, HOT enhanced by teleoperation was improved previous controllability.
In this paper, we newly propose an on-chip sensing of stimulant property of Pleurosira laevis (P. laevis) by magnetically driven microtool (MMT) which can stimulate the single cell in the microchip. To measure the applied force by MMT, the frame structure is attached to the tip of MMT. The design and fabrication of the force sensing structure with a displacement magnification mechanism of the beam deformation is shown. We also show the fabrication method to avoid the friction between the force sensing structure and the substrate of the microchip. By using this method, the MMT with very thin structure is easy to be assembled in the microchip without any damage. Through the basic experiments, the advantage of the proposed layer fabrication technique and the performance of the force sensing is confirmed. Finally, the basic characteristics of the P. laevis are investigated by using the developed MMT which is placed into the microchip.