In this paper, we propose an off-line planning algorithm for cooperative sweeping of multiple mobile robots. Sweeping of a whole work area is fundamental and essential task of mobile robots. For efficient cooperation, setting appropriate burden onto each robot is very important because interference of robots and overlaps of their sweeping units make efficiency low. In proposed algorithm, sweeping cost is evaluated by means of length of paths on which robot should move. We introduce both edges of the configuration space and Voronoi diagram so as to compute paths in the whole area. We generate a tour for traversing all the paths by applying the algorithm of the Chinese Postman Problem. According to the cost evaluation, appropriate paths of the tour are assigned to each robot. The efficiency of the proposed algorithm is verified by simulations.
In this paper, we suggest the means of speech synthesis using Mechanical Speech Synthesizer which seems to be suitable for humanoid robot. The present speech synthesis by software systems or electrical circuits do not sufficiently take the mechanism of human speech production into consideration. Therefore, in this research, we make the system of speech synthesis using the model which has human-like regions related with speech production. We synthesize speech by controlling the model's regions as a man controls. As this system will be able to reproduce the physical phenomenon during speech production, this means of speech synthesis is expected to be able to synthesize natural speech as a man produces. For the first step to our research, we made a clay model of vocal tract, and estimated the three-dimensional shapes of its tongue and lips for synthesizing Japanese steady vowels.
In our previous work we proposed two approaches to singularity treatment: one is based on a null space notation, and the other on an adjoint Jacobian. We call these approaches as the singularity-consistent approach. Both meth-ods guarantee the direction of motion in the whole work space, without producing an infeasible joint velocity. The performance has been experimentally verified with 3-DOF manipulators. In this paper, we apply the method to a real telerobot system with a non-redundant 6-DOF manipulator as the slave. We analyze the velocity relation at the singularities of this manipulator, and discuss several important implementation issues. The experimental results show that the 6-DOF manipulator can be operated safely with feasible joint velocity and without any error in the direction of motion.
The kinematics, statics and stiffness effect of a 3D grasp by a multifingered hand is investigated considering the rolling contact at the fingertip. By representing the local shape of the fingertip and the object by a quadratic surface and by linearization of the fundamental formulae, the kinematic-static relation for the motion-force of the fingertip, contact location and the object is derived. Additionally, the stiffness effect for object motion caused by the change of the contact force and the contact location at the fingertip is analyzed. The influence of the stiffness effect on the stability of the grasp is quantitatively evaluated for the grasp by a three-fingered hand.
Shape and size of food material in a production line are not always well-formed as models which are accurately described in general. Also, there is no uniformity in their sizes and hardnesses. Moreover, food materials are not so precious to be handled one by one by manipulators. This paper focuses on sorting works of such objects like food materials giving us eye-fatigues to do, and proposes a sorting method of scattered objects on a conveyor automatically with uniformity, utilizing synchronously scanned styluses which we call isolators by supposing that the shapes of the objects are most likely circular and planar, and their sizes are much alike. The objects are pushed by rotating isolators, so that the objects are separated with a certain gap among them. Behaviors of the isolators, generation of their motional patterns, optimal design of the patterns are described. Simulation of sorting for verifying functions of the isolator motion, and also fabrication of the sorting system for showing practical usefulness are presented.
This paper presents two kinds of motion control methods for a free-flying multi-link system with nonzero angular momentum. The first one deals with the optimization of both joint trajectory and initial angular momentum. The second one is based on the optimization of the velocity of the traveling function along a given joint path. Throughout these optimizations, not only are initial and final conditions satisfied, but also midway behavior is controlled. Numerical simulations have been executed compared to twist somersault performance of gymnast, and the results show the validity of these methods.
This paper discusses on a method of computing the scale of magnification, the angle of rotation, and the quantity of parallel translation that is based on a Hough transform and a Fourier transform. This method applies a Radon transform to images in all directions, differentiates the Radon transformed planes, divides the differentiated planes into positive and negative areas, computes the power spectra of period 2π by applying one-dimensional Fourier transforms to positive and negative differentiated planes, applies a Mellin transform, and gets the scale of magnification and the angle of rotation. Known methods by using 2D Fourier transforms are unable to compute uniquely the angle of rotation from power spectra since they are π-periodic. The proposed method can compute uniquely the angle of rotation from power spectra since they are 2π-periodic. Moreover, to reduce the computational cost, a Radon transform is replaced by a Hough transform by taking account of edges. Experiments were applied to actual images of industrial parts.
We propose a new time-optimal control method for robot manipulators in this paper. In the proposed method, we consider a class of desired motions whose spatial paths are same but the time trajectories are different. The purpose of this method is to find out a feedforward input pattern which can generate a minimum-time motion under conditions on limitations of actuator power and velocity. The input pattern for the minimum time motion is constructed from basic input patterns which have been already obtained by“Iterative Learning Control”. Therefore, the minimum time motion is realized through actual iterative operations without estimating physical parameters of the robot manipulators.
Kinematics of Grasping and Manipulation by multi-fingered rbotic hands where Multi-Finger-Surfaces are in contact with an object (GMMFS problem) is a problem to obtain finger joint displacements q and the position of contact points r of two curved surfaces of the fingersurface and the object for the given object position and orientation rw (inverse kinematics), and to obtain rw and r for the given q (direct kinematics) . In the previous paper, fundamental contact equation and three contact motions (i.e., pure rolling, twist rolling and slide rolling) in manipulation were formulated. Some examples of analytical solution for object dealing with simple shapes such as block, sphere, cylinder, etc. were shown. In this paper, a new method for solving the GMMFS problem of object with complicated shape is proposed. Assuming that finger has cylindrical links and ellipsoidal tip, and object is composed of B-spline surfaces, the contact equation of the finger and the object is solved by numerical recursive calculation, where six cases of the contact solution are used. The new method gives all possible solutions for the contact of the finger and the object. Simulation system of the GMMFS with a B-spline surface object is developed. Some examples of simulation of the GMMFS with the B-spline surface object are illustrated.
We propose a free-flying space robot of which center-of-mass is fixed on the base body and invariant to change of the configuration. The space robot with the center-of-mass invariance has the following characteristics: (1) it is easy to simplify an experimental system on the earth, (2) a cost of computing the Generalized Jacobian is reduced, (3) motion in a two-dimensional plane is holonomic. We developed a prototype of such a space robot, and compare the results of an experiment with it and of a numerical simulation.
In this paper, a method for detecting kinematic constraints in a plane when the shapes of the grasped object and the environment are not given is presented.It is one of the important function for intelligent tasks of home, maintenance, assembly and disassembly robots. This method utilizes the displacement and force information obtained by“active search motion”of a robot. In reality, this information includes some uncertainties such as friction, slack and elasticity. A new neural network configuration for this detection is proposed. It consists of two multilayer networks (primary and secondary network) . The primary network learns the movable space (constraint) obtained by the search motion. By the generated link weights which reflect the movable space, the secondary network determines the type and the orientation of the constraint. Simulation and experimental results are presented and analyzed.
This paper proposes a new method of non-invasively and unrestrainedly diagnosis for the Sleep Apnea Syndrome (SAS) by TV image. The SAS is a disease that a patient stops breathing in sleep intermittently. A remarkable feature of the method is that the system is able to diagnose the SAS without directly attaching any sensors to the patient by utilizing image processing. This paper describes the method theoretically from the physiological point of view. The method consists of the following steps: 1) With an image processor, the system calculates optical flows from magnified images of the breast and the abdomen of the patient. 2) The system obtains medical parameters for the SAS diagnosis from the optical flows. The effectiveness of the proposed method is proved through applying an experimental system to some SAS patients with a help of doctors and nurses at a hospital.