A high-fidelity attitude estimation technique is proposed for mobile robots which move irregularly in wide space, where heterogeneous inertial sensors are combined in a complementary way in the frequency domain. While the working frequency ranges of each sensor are not necessarily complementary, inverse models of them compensate the sensor dynamics and enlarge their effective working ranges. The problems to be addressed are that the sensor dynamics displays a highly nonlinear property in the case of 3D rotation, and, even if it is approximated by a linear system, the inverse models of them tend to be non-proper and unstable. An idea is to decouple it into the dynamics compensation part approximated by a linear transfer function and the strictly nonlinear coordinate transformation part. By inserting the designed filter before the coordinate transformation, the total transfer function is guaranteed to become proper and stable. Particularly, the differential operator of a high-pass filter cancels the integral operator included in the dynamics compensation of the rate gyroscope, which causes instability.
There has been many problems in situations surrounding children such as child neglect, deterioration in the quality of play, etc. We believe that robotic playmates would greatly help to solve these problems. In this paper we propose a playmate robot system that can play with a child. Unlike many therapeutic service robots, our proposed playmate system is implemented as a functionality of the domestic service robot with a high degree-of-freedom. This means that the robot can play with children at a high level, i.e., beyond a therapeutic effect, using its physical features. To sustain the player's interest in the system, we also propose an action selection strategy based on a transition model of the child's mental state. The robot can estimate the child's state and select an appropriate action in the course of play. Part of the proposed algorithms was implemented on a real robot platform, and experiments were carried out to design and evaluate the proposed system.
In this paper, we fabricate and evaluate new probe device which can realize handling of micro objects using thermal gel. In general, probe devices are one of the important devices for micro manipulation. However, conventional probe devices have some problems: difficulty to release the handled objects by the surface force and damage to the manipulated objects. As one solution of these problems, we proposed “Thermoresponsive Gel (GeT) probe”. The probe has an electrode at the tip and the thermoresponsive polymer can be gelled when a current is applied to the electrode. The assembly of three dimensional structures was demonstrated by the probe. The grasping force by the probe was measured using AFM cantilever. The handling of yeast cell and liposome were also realized by the probe. Finally, handling of micro objects in pure water was conducted using another micropipette. The results validate that the probe can realize the soft handling by the thermal gel and realize the precise positioning by reducing the effect of surface force.
This paper demonstrates the relationship between the production process of a knot and robot hand skills. First, we define the descriptions (rope intersection and fixed position) of a knot. Next, the characteristics of the robot hand skills are clarified from viewpoint of the description of the knot. Then, in order to obtain the production process of knot, we propose an analysis method based on the structure of knot and the characteristics of the robot hand skills. And, we analyze various knots using the proposed analysis method. Finally, in order to validate the production process obtained by the proposed analysis method, an experimental result of half hitch is shown by using a high-speed multifingered hand system.
This paper describes a stereo-based person tracking method for a person following robot. Many previous works on person tracking use laser range finders which can provide very accurate range measurements. Stereo-based systems have also been popular, but most of them are not used for controlling a real robot. We previously developed a tracking method which uses depth templates of person shape applied to a dense depth image. The method, however, sometimes failed when complex occlusions occurred. In this paper, we propose an accurate, stable tracking method using overlapping silhouette templates which consider how persons overlap in the image. Moreover, we decrease the number of image comparison by using an approximated likelihood map based on kernel density estimation. Experimental results show that the proposed method is able to reduce the processing time greatly without dropping the tracking performance.
In this paper, dynamic biped locomotion is considered with the goal of achieving fast and dexterous leg motion. We propose a new movement principle for legged robots, which produces propulsive force using frictional asymmetry. The dynamic locomotion consists of sliding motion based on the kinematic constraint and jumping motion which enables to keep the maximum horizontal velocity. The dynamics of the 2-DOF biped robot is analyzed to obtain motion characteristics for developing a motion strategy. Experimental results are also shown in which a 2-DOF biped robot takes fast short steps repetitively with compensation of the landing time by high-speed vision.
The current orientation estimation is the principal task for mobile robots. We have been developing the orientation estimation method for indoor mobile robots, using the properties of the ordinary building structure, which we can assume that most of walls and furnitures are arranged in parallel or perpendicular to the dominant direction. Based on this assumption, robots can detect the characteristic geometry of environment efficiently. In this paper, we propose two kinds of methods to find the dominant direction of the building from the surrounding range data based on these characteristics, to estimate the orientation of the robot by the scanned range data. And we present the results of experiments to verify the effectiveness of the proposed methods.