基于分布式系统的虚拟力感知与交互技术

针对现有人机交互系统中的力觉交互沉浸感不足的问题,提出了一种基于分布式系统的动态碰撞检测与虚拟力觉交互的控制策略。力觉交互系统采用分布式设计,主要包括:人机交互接口管理、空间位形解算和运动控制与碰撞检测等单元设计。在交互过程中,采用分层方式处理碰撞效果。根据模型所处虚拟空间的相对几何位置与碰撞后的运动状态构建虚拟力觉,并由交互管理单元映射至实体交互设备,实现操作者的力觉感知与交互。采用PHANTOM omni力反馈设备与Visual Studio 2010构建了动态碰撞检测的仿真实验系统,并进行了虚拟力觉交互实验。实验结果表明:操作者通过力反馈设备能够实现力觉感知与交互,有效解决了交互过程中的力觉效果不足的问题。     

虚拟装配中基于导纳控制的力觉渲染技术

传统的力触觉渲染多采用阻抗控制,不能很好地满足虚拟装配的应用要求,相比之下导纳控制模式更适用这一领域.为此提出一种基于导纳控制的双线程力觉渲染构架,并给出相应的力觉渲染算法.首先建立用于导纳控制的动力学模型,并讨论了碰撞和约束这2个状态下的力觉渲染;为了使用力觉交互接口进行虚拟装配中的小间隙装配,提出物理约束与几何约束结合的力觉渲染方法;最后针对物理计算和力反馈循环2个线程刷新频率不匹配的问题,利用二次拉格朗日多项式进行数值插值,实现了力觉交互接口的平稳输出.通过力反馈设备与自主开发的虚拟装配原型系统VAPP的连接与应用,验证了所提出的算法满足虚拟装配系统中力觉交互的应用要求.     

基于实时点云建模虚拟夹具辅助力觉交互研究

为满足遥操作的精度和实时性要求,应对在操作过程中出现的目标工件形状发生变化或与机械臂末端间出现相对移动等状况,提出一种融合RGB与深度图像信息的点云建模方法。对未知的操作环境进行实时建模,在此基础上实时构建虚拟夹具,继而研究遥操作系统中的力觉交互环节。实验结果表明,基于实时点云建模的虚拟夹具能够有效辅助操作者操纵力反馈设备与点云进行力觉交互,力觉临场感效果良好,可用于规避固定或动态障碍物,完成相对精确的操作任务。     

一种虚拟手术二维力觉交互装置的力学模型

对力交互装置在虚拟手术巾有着广泛的应用,作为基础研究,提出一种二维力觉交互装置的反馈力模型,通过模拟虚拟器械与肌肉组织和骨骼碰撞时的受力情况,验证模型的合理性。首先,根据人体组织的生物力学性能,参照Kamopp模型和胡克定律提出了系统的反馈力模型;然后针对系统的性能指标,通过对肌肉和骨骼两种组织的碰撞实验,验证了设备在虚拟手术过程中反馈力实现效果。仿真结果显示,反馈力方法能较准确地仿真力的变化,准确地感知骨骼的位置,对于虚拟手术系统的实用性具有重要意义。     

交互式乐器演奏的六自由度力觉渲染方法

目的在进行虚拟乐器交互演奏时,需要模拟触力觉-视觉-听觉多通道同步反馈,其中触力觉反馈的难点在于模拟人手操作乐器的六自由度(6-Do F)力觉交互过程。方法提出一种基于混合模型和单边约束优化的六自由度力觉合成方法,实现了虚拟人手和琴弦的多点多区域接触力觉模拟。虚拟人手采用层次化球树模型表达,古琴采用混合模型表达,其中琴体和琴弦分别采用层次化球树模型和直线解析模型。提出了基于混合模型的离散碰撞检测算法,实时检测虚拟手和琴弦是否产生碰撞;基于发生碰撞的几何元素对建立单边不可穿透约束方程,通过Active Set方法求解约束优化后方程,获得6维位姿变量保证图形显示场景中的虚拟手不会和琴弦产生穿透。为模拟琴弦变形,提出变直径的圆柱体模型来模拟琴弦在不同振动幅度下的动力学响应;提出交互状态敏感的力计算模型以刻画人手在弹奏不同状态琴弦(静态、振动态)的力觉感受差异。结果基于力觉交互设备Phantom Premium 3.0建立了实验平台,实验结果表明,本文算法可以模拟单点、多点等不同接触状态,并能模拟6维力和力矩,操作者可以感受到琴弦振动时的细腻力感觉,力觉交互过程稳定,算法计算效率在1 k Hz以上。结论算法可模拟针对琴弦一类的超薄形状物体的多点接触力觉交互过程,算法计算效率高,包含碰撞检测、约束优化、琴弦变形仿真等计算回路的更新频率也能达到要求,该混合模型能为后续复杂形状物体的碰撞响应研究提供思路。     

柔索牵引式力觉交互机器人控制策略

为了让航天员在没有太空真实环境的地面上模拟太空环境进行虚拟作业训练,设计了一种与虚拟现实（VR）技术相结合的柔索牵引式力觉交互机器人．首先,根据微重力环境中物体的运动特性设计机器人的构型,建立移动平台、驱动单元、人推物体运动过程的动力学模型并进行运动学分析．然后,针对系统冗余驱动及力控制任务,提出一种复合控制策略,即以柔索长度变化为速度控制内环,力的外环控制为力／速混合控制．最后,分别进行单柔索加载和人机系统力觉交互仿真分析,分析结果表明该控制策略可以使柔索驱动单元降低10%的恒力跟随误差并能稳定地跟随余弦力的变化,验证了该控制策略对多余力抑制的有效性．     

仿真培训中的操作票专家系统研究与应用

介绍一种应用于仿真培训的操作票系统。除了智能自动开票的功能之外,还引入了培训和考核功能。利用仿真变电站的半实物仿真环境,引入了在线培训的培训方法,允许学员对仿真设备进行实物操作,可以大大提高培训效果,具有重大的现实意义。     

仿真培训中的操作票专家系统研究与应用

介绍一种应用于仿真培训的操作票系统。除了智能自动开票的功能之外，还引入了培训和考核功能。利用仿真变电站的半实物仿真环境，引入了在线培训的培训方法，允许学员对仿真设备进行实物操作，可以大大提高培训效果，具有重大的现实意义。     

临场感智能采灰器的设计

为了提高煤灰测验工作中的煤灰采样效率问题,介绍了单自由度主从式力觉临场感和视觉临场感遥操作电厂智能采灰器的设计和低成本实现方法.由操作者操纵的力反馈操纵杆装有直流力矩电机,与环境作用的采样器选用输出力大、可靠性高的液压伺服驱动.采用一种二通道位置-力控制结构,并且力控制采用了积分分离PID控制.最后通过实验进一步分析说明所设计的体系结构的合理性和可行性.     

基于指纹IC卡的驾驶培训管理系统车载设备设计

结合指纹识别与IC卡技术,以SPCE061A单片机为控制核心,实现驾驶培训管理系统车载设备的设计方案.系统采用光学指纹识别模块FDA01采集学员指纹,通过比对IC卡内存储的学员报名时的指纹验证身份:利用IC卡实现对学员整个培训过程中静态信息和动态信息的记录存储.设计为保证信息化驾驶培训管理的真实性和准确性提供有效的车载设备解决方案.     

A hybrid haptic guidance model for tank gunners in high precision and high speed motor skill training

Haptic-based paradigms for human motor skill training which include virtual fixture, record-play method, shared control scheme and haptic disturbance have been proposed and widely used for applications like surgery, assembly, rehabilitation, motor skill and so on. However, no haptic-based training scheme applies to all types of human motor skills that new ideas and new approaches should be explored for some special training tasks. For example, tank gunners have to be rigorously trained to be able to complete the most accurate manipulation in the shortest possible time. Accuracy and operating speed are both critical for them to grasp the skill; therefore, tank gunnery is defined as a type of high precision and high speed human motor skill. In this paper, a hybrid spring-damper model which fuses haptic fixture and record-play is presented to simultaneously train accuracy and operating speed. The training approach is suitable for novices at all levels since force feedback is decomposed into two components: one for training accuracy, the other for training speed. The virtual envelope depicting is chosen as the training task for novices to validate the effectiveness of the proposed haptic-based scheme in high precision and high speed skill training. Experimental results indicate that force feedback generated based on the hybrid model can benefit novices in fast improving performances on tank gunnery.     

Examining efficient instructional methods for computer-aided brush coating skill training system in elementary and secondary education

In recent Japan, many elementary and secondary school children strongly feel an awareness of resistance toward manufacturing class. It is considered as one of the aversion causes to science and engineering. We suspect that the shortage of teacher’s manufacturing experience is related to this background. So, the authors previously have developed a brush coating skill training system with a haptic device to improve the ability. In the skill training, historically, the instruction method while reproducing the video of trainee’s action has been considered to be effective. Thus, our developed system includes a software system to visualize the brush coating motion. This software system can record trainee’s brush coating motion and visualize the data in virtual three-dimensional space, so the advisor and the trainee can share his/her skill level and the wrong motion such as extra shaking and tilt by reproducing his/her past training data on a computer screen. In this paper, to improve the learning effectiveness of our brush coating skill training system, some kinds of instructional methods are designed, and the difference of the instructional methods is analyzed based on the proposed criteria. This paper performed some experiments with 10 college students who have less experience of brush coating. From the analysis results, the most effective instruction method was clarified.     

Proposal of an Index for the Operator’s Haptic Sensation in a Master-Slave System with Force-Feedback Function

This article proposes an index to estimate the operator’s haptic sensation of the contact between the slave device and the environment in operating master–slave systems with force feedback function. The index value is derived from the velocity information of the master device before and after contact, which is hypothesized to represent the intensity of haptic sensation stimuli presented to the operator. Two characteristics of this index are discussed by means of psychophysics experiment, which are the statistical characteristics of the index value for different operators, and how the change in the operator’s haptic sensation is reflected on the index value. The index is validated by another psychophysics experiment. The experimental results show that the performance of operator’s haptic sensation can be predicted correctly based on the proposed index value. This index is expected to be applied in the parameter design of bilateral-control systems with force feedback function.     

A Survey of Haptic Rendering Techniques

Computer Graphics technologies have developed considerably over the past decades. Realistic virtual environments can be produced incorporating complex geometry for graphical objects and utilising hardware acceleration for per pixel effects. To enhance these environments, in terms of the immersive experience perceived by users, the human's sense of touch, or haptic system, can be exploited. To this end haptic feedback devices capable of exerting forces on the user are incorporated. The process of determining a reaction force for a given position of the haptic device is known as haptic rendering. For over a decade users have been able to interact with a virtual environment with a haptic device. This paper focuses on the haptic rendering algorithms which have been developed to compute forces as users manipulate the haptic device in the virtual environment.     

Development of haptic devices using flexible sheets for virtual training of abdominal palpation

A haptic device using flexible sheets for virtual training of abdominal palpation is proposed, mainly focusing on light and deep palpation. This device forms a semicylinder using two boards with rounded corners and two layered flexible sheets made of rubber. The device imitates the form of an abdomen. A trainee doctor touches and pushes everywhere of the upper sheet directly with his/her fingers and palm or single hand and both hands, regarding it as a virtual abdomen. Pulling the lower sheet lengthwise varies the softness of the sheet: the stretched sheet feels hard and the loose sheet feels soft. The trainee doctor can feel different softness of abdomens by pushing the device. Pulling the upper sheet in waistline direction depresses the centre of the device between the boards like a saddle. Stretching and loosening the upper sheet simulates up-and-down movement of an abdomen due to breathing. As a result, the trainee doctor can experience virtual abdominal palpation in the similar way as real palpation. The softness and depression at the centre of the device are measured for different tensions of the upper and lower sheets, and are compared with the measured softness and up-and-down movement due to breathing of real abdomens. A skilled physician evaluates that the device can present different softness in the range of softness of real abdomens and that the up-and-down movement of the device resembles that of real abdomens due to breathing. The empirical and sensory criterion of the physician is ascertained quantitatively using the device: he pushes abdomens until he feels the same reaction force, regardless of their softness.     

Haptic rendering for dental training system

Immersion and interaction are two key features of virtual reality systems, which are especially important for medical applications. Based on the requirement of motor skill training in dental surgery, haptic rendering method based on triangle model is investigated in this paper. Multi-rate haptic rendering architecture is proposed to solve the contradiction between fidelity and efficiency requirements. Realtime collision detection algorithm based on spatial partition and time coherence is utilized to enable fast contact determination. Proxy-based collision response algorithm is proposed to compute surface contact point. Cutting force model based on piecewise contact transition model is proposed for dental drilling simulation during tooth preparation. Velocity-driven levels of detail haptic rendering algorithm is proposed to maintain high update rate for complex scenes with a large number of triangles. Hapticvisual collocated dental training prototype is established using half-mirror solution. Typical dental operations have been realized including dental caries exploration, detection of boundary within dental cross-section plane, and dental drilling during tooth preparation. The haptic rendering method is a fundamental technology to improve immersion and interaction of virtual reality training systems, which is useful not only in dental training, but also in other surgical training systems. Supported by National Natural Science Foundation of China (Grant Nos. 60605027, 50575011), National High-Tech Research & Development Program of China (Grant No. 2007AA01Z310)     

A new desk-top encounter-type haptic device with an actively driven pen-tablet LCD panel

In conventional haptic devices for virtual reality (VR) systems, a user interacts with a scene by handling a tool (such as a pen) using a mechanical device (i.e. an end-effector-type haptic device). In the case that the device can ‘mimic’ a VR object, the user can interact directly with the VR object without the mechanical constraint of a device (i.e. an encounter-type haptic device). A new challenge of an encounter-type haptic device is displaying the visuals and haptic information simultaneously on a single device. We are proposing a new desk-top encounter-type haptic device with an actively driven pen-tablet LCD panel. The proposed device is capable of providing pseudo-3D visuals and haptic information on a single device. As the result, the system provides to the user a sense of interaction with a real object. To develop a proof-of-concept prototype, a compact parallel mechanism was developed and implemented. The aim of this research is to propose a new concept in haptic research. In this paper, the concept, the prototype, and some preliminary evaluation tests with the proposed system are presented.     

A haptic-based approach to virtual training for aerospace industry

In the last years, the industrial world has been increasingly adopting computer-aided solutions for design for maintainability and maintenance training tasks with the goal to reduce development costs and to shorten time, and to improve product and service quality. Computer-based training systems created to simulate machine assembly maintenance are normally operated by means of ordinary human–computer interfaces (keyboard, mouse, etc.), but this usually results in systems that are far from the real procedures, and therefore not effective in terms of training. In this study, we show that a better solution may come from the combination of virtual reality techniques and haptic interaction. To this regard, we present the results of a research aimed at testing and evaluating the effectiveness of the haptic feedback for first-person maintenance tasks targeted to the aerospace industry. The proposed system implements an interaction environment in which each of the main maintenance activities can be simulated by the trainee exploiting a hand-based commercial haptic device, operated by means of specific haptic-rendering techniques to provide realistic feedbacks during manipulation. A usability study is included to help assessing the potential of this approach.     

Scaled teleoperation system for nano-scale interaction and manipulation

In this paper, a visual and haptic human–machine interface is proposed for teleoperated nano-scale object interaction and manipulation. Design specifications for a bilateral scaled tele-operation system with slave and master robots, sensors, actuators and control are discussed. The Phantom? haptic device is utilized as the master manipulator, and a piezoresistive atomic force microscope probe is selected as the slave manipulator and as topography and force sensors. Using the teleoperation control system, initial experiments are realized for interacting with nano-scale surfaces. It is shown that fine structures can be felt on the operator's finger successfully, and improved nano-scale interaction and manipulation using visual and haptic feedback can be achieved.