A kinematic analysis of a haptic handheld stylus in a virtual environment: a study in healthy subjects

<p>Abstract</p> <p>Background</p> <p>Virtual Reality provides new options for conducting motor assessment and training within computer-generated 3 dimensional environments. To date very little has been reported about normal performance in virtual environments. The objective of this study was to evaluate the test-retest reliability of a clinical procedure measuring trajectories with a haptic handheld stylus in a virtual environment and to establish normative data in healthy subjects using this haptic device.</p> <p>Methods</p> <p>Fifty-eight normal subjects; aged from 20 to 69, performed 3 dimensional hand movements in a virtual environment using a haptic device on three occasions within one week. Test-retest stability and standardized normative data were obtained for all subjects.</p> <p>Results</p> <p>No difference was found between test and retest. The limits of agreement revealed that changes in an individual's performance could not be detected. There was a training effect between the first test occasion and the third test occasion. Normative data are presented.</p> <p>Conclusion</p> <p>A new test was developed for recording the kinematics of the handheld haptic stylus in a virtual environment. The normative data will be used for purposes of comparison in future assessments, such as before and after training of persons with neurological deficits.</p

Preliminary Evaluation of the MTCA.4 BPM Electronics Prototype for the PETRA IV Project

Within the PETRA IV project at DESY, thesynchrotron radiation source PETRA III will be upgradedinto a low-emittance source. The small beam emittanceand reduced beam size imply stringent requirements onthe machine stability. To meet the requirements onposition measurement and orbit stability, a highresolutionBPM system will be installed in the newmachine, with about 800 BPMs and MTCA.4-basedreadout electronics.In the TDR phase of the project, I-Tech and DESY arecooperating on the realization of a BPM prototype thatwill demonstrate the feasibility of reaching the PETRA IVrequirements. Several analog, digital and SW parts aretaken from the Libera Brilliance+ instrument and arereused in the MTCA.4 BPM prototype, with someinnovations. One of them is the separation of the RFswitch matrix used for long-term stabilization: placing itnear the BPM enables also the long RF cables to bestabilized. An 8 channel RTM board, able to acquiresignals from two BPMs was developed and is also tested.This paper presents an overview of the BPM electronicsprototype and the promising test results achieved in theInstrumentation Technologies’ laboratory with the firstboards produced

Tests of the New BPM Long Term Drift Stabilization Scheme Based on External Crossbar Switching at PETRA III

For the new PETRA IV project at DESY, about 800 high 3 resolution BPMs will be installed with the readout electron­ics system based on MTCA.4 as technical platform. In order to fulfill the requested long-term drift requirement to be less than 1 micron over a period of six days ( one week of user operation), due to the machine-specific geometry the BPM cable paths have to be stabilized in addition. To achieve this demand, the well proven concept of crossbar switching was extended such that the analogue switching part is separated from the readout electronics and brought as close as possible to the BPM pickup. This contribution summarizes first proof-of-principle measurements which were performed at PETRA III using a modified Libera Brilliance+ with exter­nal switching matrix. These measurements indicate that the concept of external switching works well and that the perfor­mance of this modified test setup fulfills the specifications

A Virtual Reality Training System for Helping Disabled Children to Acquire Skills in Activities of Daily Living

Deficiency of hand function presents difficulty to disabled people in various activities of daily living. While rehabilitation training in occupational therapy is helpful for them to cope with their deficiency, the paper presents a virtual realty based system in attempt to provide an alternative approach to complement the conventional methods. The system simulates tasks of daily living in virtual environments and produces real-time interactive graphics and forces to enable trainees to practise the skills in cyberspace. Currently, three tasks are simulated, namely, door opening, water pouring and meat cutting. Visual, audio and haptic cues are produced as guidance in response to user's actions. The performance of the users is recorded automatically on the fly with quantifiable metrics to enable objective analysis of the learning progress. Findings from initial trials with disabled children show that they found it very interesting to use the system and could adapt to the virtual training environment for practicing the tasks. Further study will be conducted to improve system usability and to evaluate the training effectiveness.School of NursingRefereed conference pape

The RF BPM Electronics Concept and Developments for the PETRA IV Project at DESY

In the scope of the TDR phase for the future PETRA IV low-emittance ring upgrade project, special attention is being dedicated to the prototyping of the future BPM electronics. The large machine will use a large number of BPM pickups, around 800, and the requirements for each system will be stringent for what regards resolution, accuracy and long-term stability. To acquire and process all the signals from the Beam Position Monitors of each cell, a MTCA.4 system with 6 RF BPM modules is being prototyped by DESY and Instrumentation Technologies. Each BPM module consists of RTM and AMC cards and will sample the signals from 2 BPM pickups, with a total of 8 input channels per RTM card. The RF cables will vary in length from BPM to BPM and will be exposed to a non-controlled temperature environment. To fulfill the strict long-term stability requirements, a cross-bar switching matrix will be used. The matrix will be installed in the tunnel next to the BPM pickup and will be remotely controlled by the MTCA.4 platform’s BPM modules. The real-time digital signal processing is then able to compensate the disturbances and drifts along the cables. This contribution presents the BPM prototype, focusing on the signal processing applied from the BPM pickups until their acquisition and digitization on the application-specific RTM modules, and further processing in the FPGA of the AMC module. Preliminary results will be presented as well

The Role of Libera Brilliance+ in Developing the New MTCA.4 BPM System for PETRA IV

I-Tech and DESY are developing a BPM electronics prototype on MTCA.4 platform for Petra IV TDR. The new prototype is based on the Libera Brilliance+ BPM system (LB+), and relies on the knowledge, expertise and maturity level of the ~15 years worth of LB+ development. While the LB+ is based on the MTCA.0 technology, it is not 100% MTCA.0 nor MTCA.4 compatible, mainly due to the still emerging MTCA.x standard details at the time of the LB+ conceptualization.The impact of the LB+ heritage, both in terms of RF electronics, as well as the application and framework maturity on the porting to the new MTCA.4 based BPM prototype is discussed. The similarities and differences of both platforms are discussed as well. Regardless of the new external (in-tunnel) switching concept being used, it was exactly the LB+ maturity that minimized the required porting effort, and most importantly, minimized the risks and enabled the short time-to-prototype – a strategy that gave us the opportunity to deliver the prototype in due tim