A new programming method named CCL (cell control language) for factory-automation systems has been developed. In CCL programming, a sequence of machine actions is described with a subclass of Petri nets. This subclass is almost equivalent to a state transition diagram, and each step of the sequence is described in a high-level language based on SLIM (standard language for industrial manipulators; JIS B 8439) . Consequently, as a development environment for CCL programs, CCL Editor is developed. CCL Editor has a graphical user interface for editing a sequence by using the subclass of Petri nets and for describing each step of the sequence in the SLIM-based language. Moreover, CCL Editor has the functions for generating executable programs from CCL source modules and for monitoring execution status of the program in real time. Using CCL, we can increase productivity and maintainability of programs for factoryautomation systems.
This paper proposes the design method of multiple sensory bilateral control for the fingered manipulator. Multiple sensory bilateral control integrates force sensors and tactile sensors information based on conventional bilateral control. It evaluates the finger shape control which is deeply effected in finger grasp operation using operator finger's vector. Designed system function is examined by solidity or shape recognition, and task execution experiment. It showed the multiple sensory bilateral control and its design method are approved.
This paper presents a methodology of environmental support for autonomous mobile manipulators using visual marks with memory storage. The mark makes up for insufficient ability of sensing and recognition; self-positioning, positioning of objects, and deciding methods to operate objects. The mark proposed in this paper consists of landmark part and memory part. The landmark part is to be estimated the relative position and orientation between robots and the mark. The memory part is to have information about what it is, what tasks there are, and how to do the tasks. Task execution using the marks with real robots is described to show the effectiveness of the proposed methodology.
In this paper, we propose an algorithm of real time path adaptation for sweeping tasks by autonomous mobile robot. Sweeping means a motion that a robot covers a 2-dimensional area. A robot driven by model based path planner has to arrange its path according to real contour in real time because its map can have errors. We apply reactive motions to traditional path planning method. The proposed algorithm interprets global constraints for a sweeping task into local constraints which describe relationship between elements of a map and curves which consists of a sweeping path. An autonomous robot can obtain local conditions according to the algorithm and adjusts its path by reactive motions without heavy calculation. We verify the efficiency of the algorithm by simulations and an experiment with actual autonomous mobile robot.
This paper describes the implementation issues of visual servo controller on a Linux-based real-time operating system. The Linux operating system is a Unix-like multi-user multi-task operating system and it is distributed freely. The real-time linux module adds a capability for hard real-time functionality, that is necessary for robot control, to Linux. Also a graphical user interface has been implemented on the basis of X Window System and Qt library. The implementation issues and some experimental data are presented. Discussion on the real-time control against the disturbance loads such as optical flow computation and heavy background processes are given.
To construct an optimal regulator for nonlinear systems, we need to solve a Hamilton-Jacobi partial differential equation (HJ-PDE) . However, if the system has nonholonomic constraints, the HJ-PDE has a nonsmooth solution because of the nonsmoothness of the optimal cost function. In such a case, the viscosity solution, a nonsmooth weak solution of the HJ-PDE, is obtained. In this paper, we deal with a wheeled vehicle, which is a nonholonomic system, and propose a numerical method to achieve a viscosity solution of the HJ-PDE using the dynamic programming principle (DPP) . The DPP can be applied to acquire a nonsmooth solution of the HJ-PDE. We also construct an optimal control law using derivatives of the viscosity solution of the HJ-PDE. The effectiveness of the proposed method is shown through simulations.
This paper describes a dexterous and robust manipulation system with a multi-fingered hand. Dynamic interactions between the finger-tips and the grasped object together with those between the grasped object and the environment easily cause manipulation errors and task execution errors. Pose errors of the manipulated object is toosmall to be detected in the servo cycle of the finger control. However such small errors will grow rapidly to cause task execution error unless compensation is correctly made. We have developed a task evaluation module which observes the pose change of the object in a longer time span depending on the motion primitive of the multi-fingered hand. Error-recovery strategies are developed and successfully executed based on the task evaluation. Result of experiment is finally shown.
In this paper, we present a method of easy communication with a robot similar to that which we use to communicate with each other when showing the way to some place. In traditional approaches to spatial learning, a mobile robot in unknown environments, tries to build metrically accurate maps in an absolute coordinate system, and therefore has to cope with device errors. Such learning is very important, however people view the structure of the environment topologically, the robot didn't. This view allows us to navigate without accurate measuring. When we direct someone to somewhere, we sometimes use a freehand map. If we could teach the robot to view things topologically, it could develop a map without physically visiting the environment. We use a nonsymbolic method, which is a kind of neural network with self-organizing and plasticity properties, without metrical information, our nonsymbolic method build a simpler method of communication between people and robots, which approach that which exists between people and people. Our method presents a reduction of labor in teaching and the neeslessness of special teaching or drawing techniques. With a simulation in which the robot explores corridor environments, we show its successful results in the face of random device error.
This paper describes development of a radio control wire-mobile robot with balancer for inspection and maintenance of telephone lines. We first have developed prototype wire-mobile robot with balancer. This robot could avoid obstacles, transfer to a branch wire and change the direction. However the balancer action was very late and the control of this robot was performed by a desk top computer. So, we next improved the balancer and the control system. The balancer could control automatically the center of gravity of the the robot. The radio control wire-mobile robot with the improved balancer could also avoid obstacles, transfer to a branch wire and change the direction. This robot can operate simply by manual radio control.
Image-based visual servoing interprets image change directly to camera motion, and control the position and pose of a robot mounting a camera. It does not need 3D object models and is robust for image reading errors and noise. However, because its strategy is to simply minimize the differences between the goal image and the currently obtained image, trajectory of the robot motion cannot be expected beforehand, and sometimes it results in largely inefficient motion. This paper points out that this inefficient motion is caused by interferences of translating motion and rotation of images. Then, we propose two algorithm to decouple them by using the Homography and the epipolar condition held between the goal image and the current image, and to generate the optimal trajectory of the robot motion to reach the goal position straightforwardly.
For manipulating an object stably and accurately by robot, it is frequently required to know the mass and center of gravity of the object. For the case when the weight and/or shape of an object is over the grasp capacity of a robot hand, this paper proposes a technique that can estimate the center of gravity and mass of the graspless and shapeunknown object. A plane called Gravity Equi-Effect Plane is introduced, which contains the center of gravity and a contact line where the object is in line-contact with an environment. If three or more gravity equi-effect planes, which correspond to different contact lines of an object, are obtained, the center of gravity of the object can be determined by the intersect point of these planes. In order to estimate the gravity equi-effect plane, Tip Operation with robot finger, which tips the object several times, is proposed. Then, algorithms to estimate the gravity equi-effect plane and to determine the mass and center of gravity of the object are given by fusing the fingertip position and force information measured from tip operations. Lastly, experimental verification on the proposed approach is performed.
We proposed that operations which need a constant pressing force can be performed by a general-purpose robot using a force-controlled end effector. The robot on the whole dose not need to be force-controlled, therefore a position/orientation controlled robot can be used. Drawing a line with a ball-point pen and grinding metal surface using an experimental end effector gave good results. This method can also solve the problem of collision between the object and tool at the beginning of the operation. Control characteristic will be improved if the update period of data transmitted to the programmable controller of AC servomotor is reduced.
Nonholonomic motion planning becomes one of the prime issue in robotics fields in the last ten years, and a lot of path or trajectory planning techniques are proposed by many researchers. Some of them are elegant and some are efficient, but almost all the methods has a same drawback, that is, they determine the motion based on the kinematic model derived from nonholonomic constraints without considering system dynamics. In this paper, we address a problem of optimal trajectory planning for Caplygin systems which are typical nonholonomic systems, and propose an efficient algorithm that can generate a near-optimal trajectories considering system dynamics. Proposed algorithm combines the concept of geometric phase, path parameterization technique by using B-spline, trajectory optimaization algorithm along a specified path which are originally developed for motion planning of robotic manipulators and a nonlinear programming formulation. Two examples, the rolling disk and the planner space robot, are given to illustrate the effectiveness of the proposed method.
This paper describes a vision-based servoing control scheme for legged robots to achieve a swaying task utilizing a visual servoing technique. Reactive motions are realized by the servoing scheme which makes it unnecessary to program the exact motion in advance based on the analysis of the kinematics/dynamics of the system. The proposed scheme is a hybrid one consisting of a controller to keep the distances between feet constant (a stance servoing controller), and a visual servoing controller. Some experimental results are shown to demonstrate the effectiveness of the proposed scheme.