A Robust Dual-Axis Virtual Reality Platform for Closed-Loop Analysis of Insect Flight

Virtual reality involves the creation of multisensory experience of an environment (its space and events) through artificial, electronic means; but that environment incorporates a sufficient number of features of the non-artificial world that it is experienced as “reality.” The cognitive issues of virtual reality are those that are involved in knowing and understanding about the virtual environment (cognitive: to perceive and to know). The knowledge we are concerned with in this chapter is both short term (Where am I in the environment? What do I see? Where do I go and how do I get there?), and long term (What can and do I learn about the environment as I see and explore it?). Given the recent interest in virtual reality as a concept (Rheingold, 1991; Wexelblat, 1993; Durlach and Mavor, 1994), it is important to consider that virtual reality is not, in fact, a unified thing, but can be broken down into a set of five features, any one of which can be present or absent to create a greater sense of reality. These features consist of the following five points. 1. Three-dimensional (perspective and/or stereoscopic) viewing vs. two-dimensional planar viewing. (Sedgwick, 1986; Wickens et al., 1989). Thus, the geography student who views a 3D representation of the environment has a more realistic view than one who views a 2D contour map. 2. Dynamic vs. static display. A video or movie is more real than a series of static images of the same material. 3. Closed-loop (interactive or learner-centered) vs. open-loop interaction. A more realistic closed-loop mode is one in which the learner has control over what aspect of the learning “world” is viewed or visited. That is, the learner is an active navigator as well as an observer. 4. Inside-out (ego-referenced) vs. outside-in (world-referenced) frame-of-reference. The more realistic inside-out frame-of-reference is one in which the image of the world on the display is viewed from the perspective of the point of ego-reference of the user (that point which is being manipulated by the control). This is often characterized as the property of “immersion.” Thus, the explorer of a virtual undersea environment will view that world from a perspective akin to that of a camera placed on the explorer’s head;

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Universal, computer facilitated, steady-state oscillator, closed loop analysis theory: some applications to precision crystal oscillators

Proceedings of the 1992 IEEE Frequency Control Symposium ◽

10.1109/freq.1992.269980 ◽

2003 ◽

Cited By ~ 3

Author(s):

B. Parzen

Keyword(s):

Steady State ◽

Closed Loop ◽

Loop Analysis ◽

Analysis Theory ◽

Crystal Oscillators

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Neurophilosophical and Ethical Aspects of Virtual Reality Therapy in Neurology and Psychiatry

Cambridge Quarterly of Healthcare Ethics ◽

10.1017/s0963180118000129 ◽

2018 ◽

Vol 27 (4) ◽

pp. 610-627 ◽

Cited By ~ 6

Author(s):

PHILIPP KELLMEYER

Keyword(s):

Virtual Reality ◽

Closed Loop ◽

Reality Therapy ◽

Ethical Challenges ◽

Ethical Aspects ◽

Consumer Market ◽

Ethical Implications ◽

The Past ◽

Core Concepts ◽

Legal Accountability

Abstract:Highly immersive virtual reality (VR) systems have been introduced into the consumer market in recent years. The improved technological capabilities of these systems as well as the combination with biometric sensors, for example electroencephalography (EEG), in a closed-loop hybrid VR-EEG, opens up a range of new potential medical applications. This article first provides an overview of the past and current clinical applications of VR systems in neurology and psychiatry and introduces core concepts in neurophilosophy and VR research (such as agency, trust, presence, and others). Then, important adverse effects of highly immersive VR simulations and the ethical implications of standalone and hybrid VR systems for therapy in neurology and psychiatry are highlighted. These new forms of VR-based therapy may strengthen patients in exercising their autonomy. At the same time, however, these emerging systems present ethical challenges, for example in terms of moral and legal accountability in interactions involving “intelligent” hybrid VR systems. A user-centered approach that is informed by the target patients’ needs and capabilities could help to build beneficial systems for VR therapy.

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A Digital Calibration Technique of MEMS Gyroscope for Closed-Loop Mode-Matching Control

Micromachines ◽

10.3390/mi10080496 ◽

2019 ◽

Vol 10 (8) ◽

pp. 496

Author(s):

Cheng Li ◽

Bo Yang ◽

Xin Guo ◽

Lei Wu

Keyword(s):

Theoretical Analysis ◽

Real Time ◽

Closed Loop ◽

Mode Matching ◽

Loop Analysis ◽

Calibration Technique ◽

Mems Gyroscope ◽

Real Time Mode ◽

Digital Excitation ◽

Bias Instability

A digital excitation-calibration technique of dual-mass MEMS gyroscope for closed-loop mode-matching control is presented in this paper. The technique, which takes advantage of the symmetrical amplitude response of MEMS gyroscope, exploits a two-side excitation signal to actuate the sense mode to obtain the corresponding DC tuning voltage. The structural characteristics of dual-mass decoupled MEMS gyroscope and the tuning principle of excitation-calibration technique are introduced firstly. Then, the scheme of digital excitation-calibration system for the real-time mode-matching control is presented. Simultaneously, open-loop analysis and closed-loop analysis are deduced, respectively, to analyze the sources of tuning error and system stability. To verify the validity of the scheme and theoretical analysis, the system model was established by SIMULINK. The simulation results are proved to be consistent with the theoretical analysis, verifying the feasibility of the digital excitation-calibration technique. The control algorithms of the system were implemented with a FPGA device. Experimental results demonstrate that digital excitation-calibration technique can realize mode-matching within 1 s. The prototype with real-time mode-matching control has a bias instability of 0.813 ∘ /h and an ARW (Angular Random Walk) of 0.0117 ∘ / h . Compared to the mode-mismatching condition, the bias instability and ARW are improved by 3.25 and 4.49 times respectively.

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