This research proposes a Asymmetry Parametric Excitation for a Biped Robot. In our research, we succeeded in developing an experimental parametric excited walking robot with counter weights and achieved the improvement of energy efficiency. However, the mechanism of this improvement has not been clarified. In this paper, we clarify the relation between the equipment of counter weights and the improvement of energy efficiency. It is found that counter weights create the asymmetry of the center of mass while the robot's posture during the double support phase is symmetric. This asymmetry contributes to the efficiency of restoring mechanical energy based on parametric excitation of the inverted pendulum. Therefore, a biped robot with counter weights can improve walking speed, step length, restored mechanical energy and walking energy efficiency.
This paper presents a high precision 3D measurement system by multiple mobile robots. This system is composed of three mobile robots consisting of a parent robot and two child robots. The parent robot is equipped with a 3D laser scanner, attitude sensor and a total station, and the child robots are equipped with corner cubes. The parent robot moves and stops repeatedly, and measures the 3D shape using the equipped laser scanner at several positions. Meanwhile, the child robots also move and stop repeatedly, and act as mobile landmarks for the positioning of the parent robot. To improve the positioning accuracy, several devices were replaced or newly installed. The experimental results show the system achieves quite high accuracy of the 0.03% of target's size. As an example of applications, we applied the system to shape measurement of tunnels under construction, and verified that the accuracy of the developed system is as high as a high-precise 3D laser scanner.
To make an operator feel reactive forces in teaching operations of metal spinning works with in smooth trajectories, a novel manufacturing system is proposed. Metal spinning is a plastic rotary-forming process in which a metal sheet is formed onto a rotating mandrel by forcing with a roller. A teaching device which is composed of a XY table and a handlebar with a force sensor was prototyped, instead of a joystick in common use. To conduct a shear spinning task from aluminum sheets of 0.8[mm] thickness to cone shells, the force-feedback function was implemented using a robotic bilateral master-slave control method based on a virtual internal model. While in a conventional spinning task of hemispherical parts, to smoothly operate the roller, a virtual non-holonomic model was applied, in reference to a kinematical constraint of a tool position in human-powered spinning works. It was verified that the enhanced system is easier to use than the simple bilateral master slave system through the forming experiments.
Tactile sensors using organic ferroelectrics are promising from the viewpoint of palpation because poly(vinylidene fluoride) [PVDF] tactile sensors have already been developed to evaluate living tissue. Moreover, vinylidene fluoride (VDF) oligomer is a new substance with a smaller number of VDF units than PVDF. As the piezoelectric coefficient of VDF oligomer is great and its film is thin and uniform, it is suitable for preparation of thinner film tactile sensor. On the other hand, in our previous study, we also developed a computer-based surgical simulator to simulate a catheter and guidewire in blood vessels of the brain. In this study, we investigated the palpation in vivo by the tactile sensor composed of organic ferroelectrics using our catheter/guidewire simulator. Using this simulator, the output of the sensor attached on the guidewire tip was calculated when the proximal part of the guidewire model was pushed and pulled. We used the blood vessel model where the friction coefficient or the stiffness was changed partially assuming that these changes occur by a disease. When the friction coefficient between the guidewire and the vessel was large, the sensor outputs became large. When the stiffness of the vessel was small, the sensor outputs became small.
In this paper, a novel haptic device is proposed that gives weight and friction illusions. Sensing a slip condition at the fignertip plays an important role to estimate the weight and friction of an object. This fact suggests that controlling the contact condition could yield weight and friction illusions. Based on this idea, a prototype device was developed that controls the contact condition between a fingertip and a rigid plate based on a camera-based eccentricity control. The desired eccentricity profile is given from an analytical relationship among the amount of the slip, the deformation of the contact area, and the investigation of human's force control strategy. The performance of the developed device was evaluated through human experiments. The experimental results show statistically significant difference among presented weight and friction conditions.
It is convenient for users to teach novel objects to a domestic service robot with a simple procedure. In this paper, we propose a method for learning the images and names of these objects shown by the users. The object images are segmented out from cluttered scenes by using motion attention. Phoneme recognition and voice conversion are used for the speech recognition and synthesis of the object names that are out of vocabulary. In the experiments conducted with 120 everyday objects, we have obtained an accuracy of 91% for object recognition and an accuracy of 82% for word recognition. Furthermore, we have implemented the proposed method on a physical robot, DiGORO, and evaluated its performance by using RoboCup@Home's “Supermarket” task. The results have shown that DiGORO has outperformed the highest score obtained in the RoboCup@Home 2009 competition.
The purpose of this paper is to achieve a dynamic folding of a cloth using a robot system with two high-speed multifingered hands. First, we will analyze the dynamic folding by a human subject in order to extract elements for this task. Second, a simple model of sheet-like flexible object using high-speed motion will be suggested. Third, motion planning of the robot system will be performed based on the proposed model and a simulation result will be illustrated. Fourth, the folding analysis using a triple pendulum model will be carried out. Fifth, a high-speed visual feedback control method will be proposed to grasp the cloth. Finally, an experiment result with the motion planning and the high-speed visual feedback will be demonstrated.