关键词： robot dynamics   software engineering   dynamic behavior   dynamic variability   robotic control system   robotic software system   serious development cost   Context modeling   Navigation   Robot kinematics   Runtime   Software engineering   Software Technologies   dynamic variability   robotics   software engineering  

摘要： The complexity necessary for robotics software systems to dynamically respond to or handle a variety of evolving scenarios translates into serious development costs and engineering challenges. Dynamic variability is one new strategy for supporting the dynamic behavior of robotics control systems.

关键词： snake-like robotics   nuclear power plant   Fukushima  

摘要： The snake-like robot is used for clean-up project in Fukushima nuclear disaster site. The contaminated water at the Fukushima Daiichi nuclear power plants has been purified by the water treatment system, called Advanced Liquid Processing System, co-developed by Japanese and international technologies. The system is used to remove most remaining radioactive contaminants in water that had to be stored at the facility. In this paper, a snake-like robot, incorporated with Advanced Liquid Processing System is introduced for the severe accident in the nuclear power plants in which human cannot control the cleaning-up in the sea where the radioactive materials have been submerged and some resolved in the sea water. The effective strategy of the cleaning-up is analyzed from the environmental protection aspect with the snake's biomechanics and radioactive hazards.

关键词： Flexible space robot   Jourdain's velocity variation principle   Joint friction   Active control  

摘要： It is well known that friction is an inevitable phenomenon existing in almost all mechanical systems including robotic systems. Friction can harm dynamic characteristics of mechanical systems as well as the accuracy of manual control. In this paper, we have comprehensively investigated the dynamic process of a flexible space robot with joint friction. Dynamic equation of the system is established based on the jourdain's velocity variation principle and the single direction recursive construction method. The Coulomb friction model and LuGre friction model are adopted to describe the joint friction. The calculation method for joint friction is discussed in detail. Moreover, an active controller is designed by the computed torque control method for trajectory tracking control. Simulation results indicate that the proposed model is effective in describing the dynamics response of the system. Joint friction can cause oscillation of the joint response and vibration of the flexible link, as well as affecting the precision of position control of the system. From the results we present, it can also be inferred that the Coulomb friction model is limited in describing the nonlinear features of friction. (C) 2015 Elsevier Masson SAS. All rights reserved.

关键词： Discrete actuation   Modular motor units   Soft robotics   Redundant actuation  

摘要： Human muscles contrast sharply with traditional robot actuators in that they consist of several motor units, connected in series and parallel, which can be progressively recruited. Some roboticists have explored this idea in robotic actuators, striving for improvements such as the ability to withstand partial damage, inexpensive repeatability by discrete open loop control and the potential of modular actuators. These systems, however, become rather complex or rely on less widely used actuation techniques such as piezo-actuators or SMAs to produce a compact implementation. This paper presents a novel design of a modular redundant actuation unit which can be combined in various combinations to form compliant actuators with varying characteristics. The actuation unit consists of discretely activated solenoids with an integrated compliant coupling. This paper presents the working principle and the physical implementation in detail. Failure of a single motor unit will merely lead to a loss in performance rather than failure of the actuator. Since each motor unit is discrete, neither power electronics nor control requires analog signals. Isometric experiments display the actuation characteristics and demonstrate the repeatability. The platform can be used in future work to further explore the virtues of exploiting discretization and redundancy in muscle-like control. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Robot learning   Learning from experience   Experiential learning in robots   Planning and plan execution   Action execution monitoring   Real-world experimentation   Failure contexts  

摘要： Learning is essential for cognitive robots as humans to gain experience and to adapt to the real world. We propose an experiential learning method for robots to build their experience online and to transfer knowledge among appropriate contexts. Experience gained through learning is used as a guide to future decisions of the robot for both efficiency and robustness. We use Inductive Logic Programming (ILP) learning paradigm to frame hypotheses represented in first-order logic that are useful for further reasoning and planning processes. Furthermore, incorporation of background knowledge is also possible to generalize the framed hypotheses. Partially specified world states can also be easily represented by these hypotheses. All these advantages of ILP make this approach superior to the other supervised learning methods. We have analyzed the performance of the learning method on our autonomous mobile robot and on our robot arm both building their experience on action executions online. It has been observed in both domains that our experience-based learning and learning-based guidance methods frame sound hypotheses that are useful for constraining and guiding the future tasks of the robots. This learning paradigm is promising especially for the contexts where abstraction is useful for efficient transfer of knowledge.

关键词： bending   dielectric elastomer actuators   fiber stiffening   grippers   soft robotics  

摘要： The use of few stiff fibers to control the deformation of dielectric elastomer actuators, in particular to break the symmetry of equi-biaxial lateral strain in the absence of prestretch, is demonstrated. Actuators with patterned fibers are shown to evolve into unique shapes upon electrical actuation, enabling novel designs of gripping actuators for soft robotics.

摘要： Service robots have attracted attention for more than a couple of decades, but have only recently become widely accepted in experienced markets, at least in some sectors. Thus, an increased interest for developing new service robots and applying robotic systems for new service tasks has emerged. Innovation is expected not only in terms of successful tasks, but even in developing robotic systems for tasks in other new areas.

关键词： Robotics-assisted tilt table   Treadmill   Cycle ergometer   Submaximal exercise   Anaerobic threshold   Respiratory compensation point   Cardiopulmonary exercise testing  

摘要： Background: The robotics-assisted tilt table (RATT), including actuators for tilting and cyclical leg movement, is used for rehabilitation of severely disabled neurological patients. Following further engineering development of the system, i.e. the addition of force sensors and visual bio-feedback, patients can actively participate in exercise testing and training on the device. Peak cardiopulmonary performance parameters were previously investigated, but it also important to compare submaximal parameters with standard devices. The aim of this study was to evaluate the feasibility of the RATT for estimation of submaximal exercise thresholds by comparison with a cycle ergometer and a treadmill. Methods: 17 healthy subjects randomly performed six maximal individualized incremental exercise tests, with two tests on each of the three exercise modalities. The ventilatory anaerobic threshold (VAT) and respiratory compensation point (RCP) were determined from breath-by-breath data. Results: VAT and RCP on the RATT were lower than the cycle ergometer and the treadmill: oxygen uptake (V'O-2) at VAT was [mean (SD)] 1.2 (0.3), 1.5 (0.4) and 1.6 (0.5) L/min, respectively (p < 0.001);V'O-2 at RCP was 1.7 (0.4), 2.3 (0.8) and 2.6 (0.9) L/min, respectively (p = 0.001). High correlations for VAT and RCP were found between the RATT vs the cycle ergometer and RATT vs the treadmill (R on the range 0.69-0.80). VAT and RCP demonstrated excellent test-retest reliability for all three devices (ICC from 0.81 to 0.98). Mean differences between the test and retest values on each device were close to zero. The ventilatory equivalent for O-2 at VAT for the RATT and cycle ergometer were similar and both were higher than the treadmill. The ventilatory equivalent for CO2 at RCP was similar for all devices. Ventilatory equivalent parameters demonstrated fair-to-excellent reliability and repeatability. Conclusions: It is feasible to use the RATT for estimation of submaximal exercise thresholds: VAT

关键词： 3D ToF Camera   PMD Camera   Pioneer Mobile Robots   Path-planning  

摘要： The aim of this paper is to deploy a time-of-flight (ToF) based photonic mixer device (PMD) camera on an Autonomous Ground Vehicle (AGV) whose overall target is to traverse from one point to another in hazardous and hostile environments employing obstacle avoidance without human intervention. The hypothesized approach of applying a ToF Camera for an AGV is a suitable approach to autonomous robotics because, as the ToF camera can provide three-dimensional (3D) information at a low computational cost, it is utilized to extract information about obstacles after their calibration and ground testing, and is mounted and integrated with the Pioneer mobile robot. The workspace is a two-dimensional (2D) world map which has been divided into a grid/cells, where the collision-free path defined by the graph search algorithm is a sequence of cells the AGV can traverse to reach the target. PMD depth data is used to populate traversable areas and obstacles by representing a grid/cells of suitable size. These camera data are converted into Cartesian coordinates for entry into a workspace grid map. A more optimal camera mounting angle is needed and adopted by analysing the camera's performance discrepancy, such as pixel detection, the detection rate and the maximum perceived distances, and infrared (IR) scattering with respect to the ground surface. This mounting angle is recommended to be half the vertical field-of-view (FoV) of the PMD camera. A series of still and moving tests are conducted on the AGV to verify correct sensor operations, which show that the postulated application of the ToF camera in the AGV is not straightforward. Later, to stabilize the moving PMD camera and to detect obstacles, a tracking feature detection algorithm and the scene flow technique are implemented to perform a real-time experiment.