基于CAN总线的力传感器与机器人控制器通讯设计

研磨机器人系统中,研磨头与工件的接触力是保证加工精度,进行机器人力控制的一个重要因 素。采用 CAN 通讯可以确保力传感器准确、及时地把力信息传送给控制器进行力控制。本文 给出了6维腕力传感器与机器人控制器通讯的硬件结构,制定了可靠的通讯协议,实现了力信 息的正确读取,为研磨机器人控制系统获得可靠的力信息提供了一种新的解决方案。

移动机器人遥操作中力反馈技术的研究

在已有的遥操作系统中增加力反馈,通过计算移动机器人与周围障碍物之间的虚拟交互力,并将其映射到操纵杆上变成操作者可以感知的力,这样操作者能感觉到机器人与环境之间的作用力,从而有效地完成操作任务.实验结果表明该方法能够有效控制机器人行走,显示了在非结构性环境下临场感在增强人机交互能力方面的优越性.

具有实时视觉/触觉反馈的纳米操作系统

由于缺乏实时的传感器信息反馈,导致传统的基于原子力显微镜的纳米操作盲目,操作效率和成功率都非常低.为了克服这一问题,设计和实现了一种具有实时视觉和三维触觉反馈的纳米操作系统.当利用该系统进行纳米操作时,操作者不但可以实时感受到探针与被操作物体间的相互作用力,还可以在3D增强现实图像界面中观察到纳米操作场景的变化,并可以在线控制探针的三维运动.这种交互式的操作系统使得纳米操作变得容易可行.纳米刻画实验和多壁碳纳米管的推动实验验证了该系统的有效性和高效率。

具有力觉与视觉反馈的交互式纳米操作系统

提出了交互式纳米操作的实现方法,搭建了一个具有力觉与视觉反馈的交互式纳米操作系统.操作者通过该系统不仅可以实时感受到作用在原子力显微镜(AFM)探针上的力,而且可以实时观察到纳米环境在AFM操作下的变化过程,使得对微观世界的纳米操作如同在宏观世界搬运物体一样直观、灵活.实验结果证实了本系统的高效性及先进性.

具有三维力反馈的原子力显微镜纳米操作系统

在基于原子力显微镜的纳米操作过程中,由于缺乏实时反馈信息,造成纳米操作效率低下且灵活性差,同时探针因受力过大而损坏。为此,本文通过对探针受力-悬臂变形进行建模,并根据实时检测到的悬臂变形信号、新的参数获取与校准方法,从而获取探针所受的实时三维纳米力。将此三力经比例放大后送入力/触觉设备进行感知,操作者就可以实时调节施加在探针上力的大小及探针的运动轨迹,使得操作的效率及灵活性明显提高,且可以避免探针因受力过大而造成损坏。纳米刻画和多壁碳纳米管的操作实验验证了系统的有效性。

基于Internet的力反馈技术研究

论述了基于Internet的力反馈技术及其相关技术的发展和研究意义 ,综合机器人遥操作控制领域的理论方法 ,结合多媒体技术的最新发展 ,构建了一种基于事件的系统结构及其设计方法 .基于该方法 ,分析了系统的可靠性、稳定性及力媒体传输的透明性 ,并设计了一个基于Internet的力反馈技术的系统实例

A Novel Multimodal Interface for Improving Visually Impaired People's Web Accessibility

This paper introduces a novel interface designed to help blind and visually impaired people to explore and navigate on the Web. In contrast to traditionally used assistive tools, such as screen readers and magnifiers, the new interface employs a combination of both audio and haptic features to provide spatial and navigational information to users. The haptic features are presented via a low-cost force feedback mouse allowing blind people to interact with the Web, in a similar fashion to their sighted counterparts. The audio provides navigational and textual information through the use of non-speech sounds and synthesised speech. Interacting with the multimodal interface offers a novel experience to target users, especially to those with total blindness. A series of experiments have been conducted to ascertain the usability of the interface and compare its performance to that of a traditional screen reader. Results have shown the advantages that the new multimodal interface offers blind and visually impaired people. This includes the enhanced perception of the spatial layout of Web pages, and navigation towards elements on a page. Certain issues regarding the design of the haptic and audio features raised in the evaluation are discussed and presented in terms of recommendations for future work.

Simultaneous remote haptic collaboration for assembling tasks

Stand-alone virtual environments (VEs) using haptic devices have proved useful for assembly/disassembly simulation of mechanical components. Nowadays, collaborative haptic virtual environments (CHVEs) are also emerging. A new peer-to-peer collaborative haptic assembly simulator (CHAS) has been developed whereby two users can simultaneously carry out assembly tasks using haptic devices. Two major challenges have been addressed: virtual scene synchronization (consistency) and the provision of a reliable and effective haptic feedback. A consistency-maintenance scheme has been designed to solve the challenge of achieving consistency. Results show that consistency is guaranteed. Furthermore, a force-smoothing algorithm has been developed which is shown to improve the quality of force feedback under adverse network conditions. A range of laboratory experiments and several real trials between Labein (Spain) and Queen’s University Belfast (Northern Ireland) have verified that CHAS can provide an adequate haptic interaction when both users perform remote assemblies (assembly of one user’s object with an object grasped by the other user). Moreover, when collisions between grasped objects occur (dependent collisions), the haptic feedback usually provides satisfactory haptic perception. Based on a qualitative study, it is shown that the haptic feedback obtained during remote assemblies with dependent collisions can continue to improve the sense of co-presence between users with regard to only visual feedback.

Complex-order dynamics in hexapod locomotion

This paper studies the dynamics of foot–ground interaction in hexapod locomotion systems. For that objective the robot motion is characterized in terms of several locomotion variables and the ground is modelled through a non-linear spring-dashpot system, with parameters based on the studies of soil mechanics. Moreover, it is adopted an algorithm with foot-force feedback to control the robot locomotion. A set of model-based experiments reveals the influence of the locomotion velocity on the foot–ground transfer function, which presents complex-order dynamics.

Perceptual cues for orientation in a two finger haptic grasp task

Single point interaction haptic devices do not provide the natural grasp and manipulations found in the real world, as afforded by multi-fingered haptics. The present study investigates a two-fingered grasp manipulation involving rotation with and without force feedback. There were three visual cue conditions: monocular, binocular and projective lighting. Performance metrics of time and positional accuracy were assessed. The results indicate that adding haptics to an object manipulation task increases the positional accuracy but slightly increases the overall time taken.

Generic control interface for networked haptic virtual environments

As Virtual Reality pushes the boundaries of the human computer interface new ways of interaction are emerging. One such technology is the integration of haptic interfaces (force-feedback devices) into virtual environments. This modality offers an improved sense of immersion to that achieved when relying only on audio and visual modalities. The paper introduces some of the technical obstacles such as latency and network traffic that need to be overcome for maintaining a high degree of immersion during haptic tasks. The paper describes the advantages of integrating haptic feedback into systems, and presents some of the technical issues inherent in a networked haptic virtual environment. A generic control interface has been developed to seamlessly mesh with existing networked VR development libraries.

Optical sensors for monitoring water uptake in plants

The monitoring of water uptake in plants is becoming increasingly important. Optical sensors offer considerable advantages over conventional methods and several sensors have been developed including an optical potometer that monitors water uptake from individual roots, the detection of xylem cavitation using audio acoustic emissions with an interferometric force feedback microphone, and an optical fiber displacement transducer that detects changes in leaf thickness in relation to leaf-water potential.

Mechatronic design of a high frequency probe for haptic interaction

Current force feedback, haptic interface devices are generally limited to the display of low frequency, high amplitude spatial data. A typical device consists of a low impedance framework of one or more degrees-of-freedom (dof), allowing a user to explore a pre-defined workspace via an end effector such as a handle, thimble, probe or stylus. The movement of the device is then constrained using high gain positional feedback, thus reducing the apparent dof of the device and conveying the illusion of hard contact to the user. Such devices are, however, limited to a narrow bandwidth of frequencies, typically below 30Hz, and are not well suited to the display of surface properties, such as object texture. This paper details a device to augment an existing force feedback haptic display with a vibrotactile display, thus providing a means of conveying low amplitude, high frequency spatial information of object surface properties. 1. Haptics and Haptic Interfaces Haptics is the study of human touch and interaction with the external environment via touch. Information from the human sense of touch can be classified in to two categories, cutaneous and kinesthetic. Cutaneous information is provided via the mechanoreceptive nerve endings in the glabrous skin of the human hand. It is primarily a means of relaying information regarding small-scale details in the form of skin stretch, compression and vibration.

Gravity well visibility in haptic interfaces for motion-impaired

Haptic computer interfaces provide users with feedback through the sense of touch, thereby allowing users to feel a graphical user interface. Force feedback gravity wells, i.e. attractive basins that can pull the cursor toward a target, are one type of haptic effect that have been shown to provide improvements in "point and click" tasks. For motion-impaired users, gravity wells could improve times by as much as 50%. It has been reported that the presentation of information to multiple sensory modalities, e.g. haptics and vision, can provide performance benefits. However, previous studies investigating the use of force feedback gravity wells have generally not provided visual representations of the haptic effect. Where force fields extend beyond clickable targets, the addition of visual cues may affect performance. This paper investigates how the performance of motion-impaired computer users is affected by having visual representations of force feedback gravity wells presented on-screen. Results indicate that the visual representation does not affect times and errors in a "point and click" task involving multiple targets.

The effect of multiple haptic distractors on the performance of motion-impaired users

The effect of multiple haptic distractors on target selection performance was examined in terms of times to select the target and the associated cursor movement patterns. Two experiments examined: a) The effect of multiple haptic distractors around a single target and b) the effect of inter-item spacing in a linear selection task. It was found that certain target-distractor arrangements hindered performance and that this could be associated with specific, explanatory cursor patterns. In particular, it was found that the presence of distractors along the task axis in front of the target was detrimental to performance, and that there was evidence to suggest that this could sometimes be associated with consequent cursor oscillation between distractors adjacent to a desired target. A further experiment examined the effect of target-distractor spacing in two orientations on a user’s ability to select a target when caught in the gravity well of a distractor. Times for movements in the vertical direction were found to be faster than those in the horizontal direction. In addition, although times for the vertical direction appeared equivalent across five target-distractor distances, times for the horizontal direction exhibited peaks at certain distances. The implications of these results for the design and implementation of haptically enhanced interfaces using the force feedback mouse are discussed.