This paper considers the posture stabilization problem of a one-legged planar hopping robot. Stabilizing the posture of the one-legged hopping robot is an essential problem for realizing running legged robots. In this paper, we propose a design method of posture stabilization control of the one-legged hopping robot via periodic linear-quadratic optimal control. We formulated the problem of traveling at a constant horizontal speed in the air while keeping the robot's posture stable as a periodic discrete-time system. The feedback control law is obtained by LQI design for the periodic discrete-time system. The advantage of this method is that it does not need the trajectory planning of the robot. The proposed method can adjust the robot's dynamic characteristics by adequately selecting the weighting matrices of the LQ criterion. The effectiveness of the proposed method is shown by numerical simulations. The simulation results showed that the proposed method enables the stable running of the robot at the specified speed provided that the hopping heights maintained constant appropriately.
This study demonstrates that a bio-inspired fingertip structure improves the grasping performance of a prosthetic hand. A prosthetic hand attached to a human user requires a higher degree of grasping stability with minimal components compared to a typical robotic hand. Precision grasping tends to be less stable than power grasping; however, the former is used more frequently in daily life. To improve the stability of precision grasping, in this study, we focused on a two-layered elastic structure consisting of epidermis and subcutaneous tissue found in the finger. The efficiency of the two-layered structure, with respect to grasping stability, was evaluated by comparing one-layered and two-layered artificial fingertips. Finally, a two-layered elastic glove was designed based on the stability of the grasping. The stability of the precision grasping was evaluated using the pendulum experiment. The developed glove showed higher stability than the conventional prosthetic hand system.
Our laboratory aim to enable robots to avoid obstacles as smoothly as humans, using only image information. It is necessary to define what information to focus on and what information to use. To get a hint for making such definition, we investigated human gaze points on the image obtained from robot's viewpoint. For this purpose, we developed an experimental system incorporated with an eye tracking system, in which a human rides on an automatic electric wheelchair considered as a mobile robot, inside which he gazes at the image obtained by a stereo camera. He controls the velocity and direction of the robot based on the image information. The obtained eye tracking data are shown and what the human gazed at are discussed.
To increase the construction site efficiency, various approaches regarding automatic control of material handling robots have been developed. In this paper, we propose an algorithm for autonomous material handling, which has been evaluated through field experiments in construction sites. The proposed algorithm of automatic control has three characteristics considering its practicalities: (i) the navigation among loading zones and unloading zones does not require a global map or self-localization; (ii) a series of operations including loading, unloading, and transportation can be carried out fully automatically; (iii) elevator operations required for vertical transportation (e.g., door opening and closing, floor selection, and detection of getting on and off) can be conducted automatically based on robot-elevator communication.
“Jet Spraying Drone” that can spray repair materials onto concrete structures has been developed. However, manual operation of drones that flies in at high altitudes makes it difficult to fly and keep a suitable position for spray works. In this study, we developed a “semi-autonomous flight system” that can keep position autonomously and have versatility. With this system, drones keep distance and angle to the target wall, and altitude autonomously, and can be operated manually only to the left and right direction. The experimental results on two different types of drones showed the flight accuracy and versatility of the system.
Ultrasonic diagnosis is noninvasive method for internal examination. However, it requires a high level of operational skill. It is expected that the new support system for effective operation is developed. In addition, tele-medicine has also been quite attractive for improvement of quality of life. From these social demands, this paper proposes a new haptic ultrasonic probe based on bilateral control. This can communicate both haptic and image information. In order to support the automatic classification of contact objects, Neural Network is implemented. It is confirmed that the integration of haptic and image information can improve the recognition rate from experiment.
This paper describes the kinematics, motion planning and mechanism optimization of the dual-arm type cable traversing robot on spatially-structured cable way. Since the inverse kinematics cannot be perfectly defined due to one of the orientation parameters is determined by static condition, its inverse kinematics algorithm utilizing both the kinematics of 3R serial spherical mechanism and the static equilibrium condition of the whole system was developed. The motion planning method to traverse cable node is based on the kinematics and Spherical Linear Interpolation using quaternion. Furthermore, mechanism optimization for avoidance of collision with cables and improvement of characteristics is also conducted.
In this study, the soft deformable fingertips with the same spring stiffness was fabricated on the basis of the spring stiffness calculated from the beam model of the soft deformable fingertip, and we confirmed that if the spring stiffness was the same, the resistible force tended to be the same. In order to verify the relationship with the change in the contact area, the rate of decrease of the contact area to reach the resistible force was defined and the relationship with the resistible force was compared for each stiffness of the finger material and cross-sectional area.