关键词： 并联机器人   Lagrange   法   滑模控制   变参趋近率   反正切函数  

摘要： 并联机构具有时变、强耦合、非线性特性,其动力学模型计算量大、耗时长,难以实现有效的实时控制。针对新型驱动冗余三自由度并联机器人的动力学控制问题,首先,采用Lagrange方法进行了完整精确的动力学建模,在此模型的基础上设计了基于指数趋近率的动力学滑模控制器,同时,为消弱滑模控制的抖振、提高控制器性能,引入反正切函数对传统指数趋近率滑模控制进行改进。最后对动力学模型进行仿真分析,并在存在初始误差的情况下进行轨迹跟踪。结果表明,所建模型正确,改进后的滑模控制器程序运行速度大大提高,跟踪快速、精度高,其突出优点是速度抖振极小、输出力输出平稳,能有效消弱系统抖振,较传统指数趋近率滑模控制器性能更好。

关键词： 自主学习   信息技术教师   能力风暴   实践教学活动   探究方法   技术探究   向右转   预测结论   接受者   延时时间  

摘要： 实验是科学课程学习的主要探究方法之一,在信息技术教学中,学生也可以通过类似科学探究实验的方式进行自主学习。因此,如何巧设探究实验,助力信息课堂,提高教学效率是信息技术教师面临的重要课题。下面笔者以《机器人学走路》（浙江教育出版社,为能力风暴VJC1.5仿真版软件）一课为例,谈谈如何设计有效的＂探究实验＂,开展探究性实践教学活动。

关键词： 食品分拣机器人   虚拟样机   动力学仿真   刚体动力学   刚柔耦合动力学  

摘要： 针对六自由度关节式食品分拣机器人的结构特点,运用拉格朗日法对所设计的机器人进行动力学分析。建立机器人的虚拟样机模型,并在ADAMS中对其进行刚体动力学仿真,得到各关节角度、角速度、角加速度、力矩以及功率曲线,发现该机器人具有较好的运动稳定性以及动态响应性,可为电机选型提供理论依据。采用SimDesigner,对所设计的机器人进行刚柔耦合动力学仿真,结果表明机械臂设计合理,可为食品分拣机器人的设计与改进提供指导。

关键词： Human behavior learning   Hidden Markov model  

摘要： Many robots, such as human guide robots and service robots, need to learn the human behavior such that the robots can merge into human society. This learning process is in task space. However, the desired trajectories should be in joint space such that each joint can be moved like human. This needs inverse kinematics. In most of cases, the inverse kinematics do not have analytical solutions. Few training methods work in joint space directly, because they need dynamic time warping to remove speed influence. Both inverse kinematics and dynamic time warping destroy the accuracy of the learning. In this paper, the desired trajectory is trained in joint space without the dynamic time warping. In order to learn the demonstrations in joint space, we use two techniques, Lloyd's algorithm and modified hidden Markov model, to solve the problems in joint space learning. Since the desired trajectories are the joint angles, they can be applied directly without inverse kinematics. Experimental results show that the proposed algorithm works well for human behavior learning. (C) 2015 Elsevier B.V. All rights reserved.

关键词： KIDNEY tumors   SURGERY   ENDOSCOPIC surgery   LAPAROSCOPY   SURGICAL robots   NEPHRECTOMY  

摘要： A letter to the editor is presented in response to the article on robot-assisted surgery by Amitabh Chandra and colleagues in the February 2015 issue.

关键词： NASA  

摘要： This paper discusses the actuator-level control of Valkyrie, a new humanoid robot designed by NASA's Johnson Space Center in collaboration with several external partners. Several topics pertaining to Valkyrie's series elastic actuators are presented including control architecture, controller design, and implementation in hardware. A decentralized approach is taken in controlling Valkyrie's many series elastic degrees of freedom. By conceptually decoupling actuator dynamics from robot limb dynamics, the problem of controlling a highly complex system is simplified and the controller development process is streamlined compared to other approaches. This hierarchical control abstraction is realized by leveraging disturbance observers in the robot's joint-level torque controllers. A novel analysis technique is applied to understand the ability of a disturbance observer to attenuate the effects of unmodeled dynamics. The performance of this control approach is demonstrated in two ways. First, torque tracking performance of a single Valkyrie actuator is characterized in terms of controllable torque resolution, tracking error, bandwidth, and power consumption. Second, tests are performed on Valkyrie's arm, a serial chain of actuators, to demonstrate the robot's ability to accurately track torques with the presented decentralized control approach.

关键词： Trials   Performance metrics   robotics   Classification (Cognitive Process)   experimentation   Humanoid robots   Sensor fusion   Robot   critical incident   DARPA   CONTROL ROOM   Teams  

摘要： In December 2013, the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge (DRC) Trials were held in Homestead, Florida. The DRC Trials were designed to test the capabilities of humanoid robots in disaster response scenarios with degraded communications. Each team created their own interaction method to control their robot, either the Boston Dynamics Atlas robot or a robot built by the team itself. Of the 15 competing teams, eight participated in our study of human-robot interaction. We observed the participating teams from the field (with the robot) and in the control room (with the operators), noting many performance metrics, such as critical incidents and utterances, and categorizing their interaction methods according to the number of operators, control methods, and amount of interaction. We decomposed each task into a series of subtasks, different from the DRC Trials official subtasks for points, to gain a better understanding of each team's performance in varying complexities of mobility and manipulation. Each team's interaction methods have been compared to their performance, and correlations have been analyzed to understand why some teams ranked higher than others. We discuss lessons learned from this study, and we have found in general that the guidelines for human-robot interaction for unmanned ground vehicles still hold true: more sensor fusion, fewer operators, and more automation lead to better performance.

关键词： Robotics  

摘要： This paper describes the technical approach, hardware design, and software algorithms that have been used by Team THOR in the DARPA Robotics Challenge (DRC) Trials 2013 competition. To overcome big hurdles such as a short development time and limited budget, we focused on forming modular componentsin both hardware and softwareto allow for efficient and cost-effective parallel development. The hardware of THOR-OP (Tactical Hazardous Operations Robot-Open Platform) consists of standardized, advanced actuators and structural components. These aspects allowed for efficient maintenance, quick reconfiguration, and most importantly, a relatively low build cost. We also pursued modularity in the software, which consisted of a hybrid locomotion engine, a hierarchical arm controller, and a platform-independent remote operator interface. These modules yielded multiple control options with different levels of autonomy to suit various situations. The flexible software architecture allowed rapid development, quick migration to hardware changes, and multiple parallel control options. These systems were validated at the DRC Trials, where THOR-OP performed well against other robots and successfully acquired finalist status.

关键词： robotic manipulators   teaching   simulation  

摘要： This paper presents a new toolbox focussed on the teaching of robotic manipulators. The library works under Matlab and has been designed to strengthen the theoretical concepts explained during the theory lectures. The educational approach is focussed on teaching the main concepts through developing math modeling and simulation. In order to do this, the toolbox aims at the fulfillment of a set of practical sessions that allow the students to test most of the concepts of an introductory course in robotic manipulators. In addition, the library possesses features that typically needed the usage of proprietary software, such as the visualization of a realistic 3D representation of commercial robotic arms and the programming of those arms in an industrial language. The practices include the concepts of direct and inverse kinematics, inverse and direct dynamics, path planning and robot programming. As a transversal practice, during the sessions, the student is asked to choose and integrate a new robotic arm in the library, proposing a particular solution to the direct and inverse kinematic problem, as well as the inclusion of other important parameters. The library has been deployed during the last year in bachelor and master studies and has received a nice acceptance. Finally, the library has been assessed in terms of usefulness, design and usage by means of a student survey. In addition, the surveys were designed to establish a relation between the student perception of the system, the time spent on the tool and their learning achievements. (c) 2014 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:443-454, 2015;View this article online at;DOI

关键词： SPECIAL issues of periodicals   REMOTE submersibles   PUBLISHERS & publishing   PERIODICAL publishing   PERIODICALS -- Articles