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.

摘要： Issue Title: Special Issue on Cognitive Robotics Systems: Concepts and Applications & Selected Papers from the National Meeting of Artificial and Computational Intelligence 2013

关键词： Off-line learning   Adaptive robot   Sequential task   Dynamic neural field   Persistent activity   Social learning  

摘要： There is currently an increasing demand for robots able to acquire the sequential organization of tasks from social learning interactions with ordinary people. Interactive learning-by-demonstration and communication is a promising research topic in current robotics research. However, the efficient acquisition of generalized task representations that allow the robot to adapt to different users and contexts is a major challenge. In this paper, we present a dynamic neural field (DNF) model that is inspired by the hypothesis that the nervous system uses the off-line re-activation of initial memory traces to incrementally incorporate new information into structured knowledge. To achieve this, the model combines fast activation-based learning to robustly represent sequential information from single task demonstrations with slower, weight-based learning during internal simulations to establish longer-term associations between neural populations representing individual subtasks. The efficiency of the learning process is tested in an assembly paradigm in which the humanoid robot ARoS learns to construct a toy vehicle from its parts. User demonstrations with different serial orders together with the correction of initial prediction errors allow the robot to acquire generalized task knowledge about possible serial orders and the longer term dependencies between subgoals in very few social learning interactions. This success is shown in a joint action scenario in which ARoS uses the newly acquired assembly plan to construct the toy together with a human partner. (C) 2015 Elsevier Ltd. 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： Neurobiology   Neuromorphics   Neural networks (Computer science)   Cognition   Robots -- Control systems  

关键词： Autism spectrum disorder   Intervention   Treatment   Robotics   Vocational   Social skills  

摘要： This pilot study evaluated a novel intervention designed to reduce social anxiety and improve social/vocational skills for adolescents with autism spectrum disorder (ASD). The intervention utilized a shared interest in robotics among participants to facilitate natural social interaction between individuals with ASD and typically developing (TD) peers. Eight individuals with ASD and eight TD peers ages 12-17 participated in a weeklong robotics camp, during which they learned robotic facts, actively programmed an interactive robot, and learned "career" skills. The ASD group showed a significant decrease in social anxiety and both groups showed an increase in robotics knowledge, although neither group showed a significant increase in social skills. These initial findings suggest that this approach is promising and warrants further study.

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： 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.