scholarly journals Improved Haptic Fidelity Via Reduced Sampling Period With an FPGA-Based Real-Time Hardware Platform

2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Marcia K. O’Malley ◽  
Kevin S. Sevcik ◽  
Emilie Kopp
Keyword(s):  
Real Time ◽  
Sampling Rate ◽  
Sampling Period ◽  
Haptic Device ◽  
Sensor Data ◽  
Haptic Interface ◽  
Hardware System ◽  
Surface Stiffness ◽  
Simulated Environment ◽  
Field Programmable

A haptic virtual environment is considered to be high-fidelity when the environment is perceived by the user to be realistic. For environments featuring rigid objects, perception of a high degree of realism often occurs when the free space of the simulated environment feels free and when surfaces intended to be rigid are perceived as such. Because virtual surfaces (often called virtual walls) are typically modeled as simple unilateral springs, the rigidity of the virtual surface depends on the stiffness of the spring model. For impedance-based haptic interfaces, the stiffness of the virtual surface is limited by the damping and friction inherent in the device, the sampling rate of the control loop, and the quantization of sensor data. If stiffnesses greater than the limit for a particular device are exceeded, the interaction between the human user and the virtual surface via the haptic device becomes nonpassive. We propose a computational platform that increases the sampling rate of the system, thereby increasing the maximum achievable virtual surface stiffness, and subsequently the fidelity of the rendered virtual surfaces. We describe the modification of a PHANToM Premium 1.0 commercial haptic interface to enable computation by a real-time operating system (RTOS) that utilizes a field programmable gate array (FPGA) for data acquisition between the haptic interface hardware and computer. Furthermore, we explore the performance of the FPGA serving as a standalone system for communication and computation. The RTOS system enables a sampling rate for the PHANToM that is 20 times greater than that achieved using the “out of the box” commercial hardware system, increasing the maximum achievable surface stiffness twofold. The FPGA platform enables sampling rates of up to 400 times greater, and stiffnesses over 6 times greater than those achieved with the commercial system. The proposed computational platforms will enable faster sampling rates for any haptic device, thereby improving the fidelity of virtual environments.

Improved Haptic Fidelity via Reduced Sampling Period With an FPGA-Based Real-Time Hardware Platform

2007 ◽  
Author(s):  
Kevin S. Sevcik ◽  
Emilie Kopp ◽  
Marcia K. O’Malley
Keyword(s):  
Real Time ◽  
Sampling Rate ◽  
Sampling Period ◽  
Haptic Interfaces ◽  
Control Loop ◽  
Passive Behavior ◽  
Field Programmable ◽  
Order Of Magnitude ◽  
System Overhead ◽  
Limiting Value

Impedance based haptic interfaces face inherent challenges in displaying stiff virtual environments. Fidelity of a virtual environment is enhanced by stiff virtual walls combined with low damping and passive behavior of the interface. However, the stiffness of virtual walls displayed on an impedance based interface is limited by the damping inherent in the controller, the sampling rate of the control loop, and the quantization of the controller’s position. Attempting to display a stiffness larger than this limiting value destroys the passivity of the interface, leading to active controller behavior and eventually closed loop instability. We propose a method of increasing the fidelity of a PHANToM Premium 1.0 commercial haptic interface by controlling it via a Field Programmable Gate Array (FPGA) both alone and with a Real Time Operating System (RTOS) control system. This custom controller enjoys several benefits over the standard control achieved via a proprietary control card in a Multitasking OS, including reduced system overhead and deterministic loop rate timing. The performance of the proposed FPGA/RTOS controller compares favorably with the performance of an FPGA/Multitasking OS controller. The FPGA/RTOS controller achieves control loop rates an order of magnitude greater than that of the proprietary controller, allowing virtual walls to be displayed with greatly increased stiffnesses, while retaining the passivity and low damping of the PHANToM interface.

Communication Method of Time Synchronization and Strength Using Haptic Interface

2014 ◽  
Vol 26 (6) ◽  
pp. 772-779
Author(s):  
Takashi Asakawa ◽  
◽  
Noriyuki Kawarazaki ◽  
Keyword(s):  
Real Time ◽  
Visually Impaired ◽  
Time Synchronization ◽  
Haptic Device ◽  
Haptic Interface ◽  
Acceleration Sensor ◽  
Vibration Strength ◽  
Music Lessons ◽  
Communication Method ◽  
Radio Signals

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00260006/10.jpg"" width=""300"" />Electric music baton system</div> We are developing an electronic baton system as an alternative haptic interface to facilitate music lessons for the visually impaired. This system incorporates an acceleration sensor in the baton, transmits data to a player via radio signals, and acts as a haptic interface by generating vibrations. In this paper, we experimentally evaluate responses to the stimulus of the visual and the tactile senses in order to verify that a haptic interface can substitute for vision in scenarios that involve real-time tasks, such as music lessons. In the first experiment, we verify that clue motions are important for both the visual and a tactile senses. Next, we test the new method of communicating strength. Thismethod uses not vibration strength but oscillating time for vibrations of the haptic device. The results of the experiment confirm that the technique is effective. </span>

Bio-Inspired Real-Time Robot Vision for Collision Avoidance

2008 ◽  
Vol 20 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Hirotsugu Okuno ◽  
◽  
Tetsuya Yagi
Keyword(s):  
Nervous System ◽  
Real Time ◽  
Collision Avoidance ◽  
Visual Information ◽  
Electronic Circuit ◽  
Robot Vision ◽  
Vision Sensor ◽  
Hardware System ◽  
Silicon Retina ◽  
Field Programmable

A mixed analog-digital integrated vision sensor was designed to detect an approaching object in real-time. To respond selectively to approaching stimuli, the sensor employed an algorithm inspired by the visual nervous system of a locust, which can avoid collisions robustly by using visual information. An electronic circuit model was designed to mimic the architecture of the locust nervous system. Computer simulations showed that the model provided appropriate responses for collision avoidance. We implemented the model with a compact hardware system consisting of a silicon retina and field-programmable gate array (FPGA) circuits; the system was confirmed to respond selectively to approaching stimuli that constituted a collision threat.

CALCULATION OF ENGINE PARAMETERS USING RECONFIGURABLE HARDWARE

2014 ◽  
Vol 11 (supp01) ◽  
pp. 1344011
Author(s):  
J. BANKS ◽  
N. A. KELSON ◽  
H. MACINTOSH ◽  
M. DAGG ◽  
R. HAYWARD ◽  
...  
Keyword(s):  
Real Time ◽  
Combustion Engine ◽  
Sampling Rate ◽  
Reconfigurable Hardware ◽  
Data Sampling ◽  
Real Time Processing ◽  
Calculation Of Parameters ◽  
Field Programmable ◽  
Data Sampling Rate ◽  
Time Calculation

The feasibility of real-time calculation of parameters for an internal combustion engine via reconfigurable hardware implementation is investigated as an alternative to software computation. A detailed in-hardware field programmable gate array (FPGA)-based design is developed and evaluated using input crank angle and in-cylinder pressure data from fully instrumented diesel engines in the QUT Biofuel Engine Research Facility (BERF). Results indicate the feasibility of employing a hardware-based implementation for real-time processing for speeds comparable to the data sampling rate currently used in the facility, with acceptably low level of discrepancies between hardware and software-based calculation of key engine parameters.

scholarly journals Real-Time Edge Neuromorphic Tasting From Chemical Microsensor Arrays

2021 ◽  
Vol 15 ◽  
Author(s):  
Nicholas LeBow ◽  
Bodo Rueckauer ◽  
Pengfei Sun ◽  
Meritxell Rovira ◽  
Cecilia Jiménez-Jorquera ◽  
...  
Keyword(s):  
Real Time ◽  
Sampling Period ◽  
Sensor Data ◽  
Chemical Manufacturing ◽  
Point Of Interest ◽  
Time Operation ◽  
Chemical Measurements ◽  
Neuromorphic Hardware ◽  
Real Time Operation ◽  
Microsensor Arrays

Liquid analysis is key to track conformity with the strict process quality standards of sectors like food, beverage, and chemical manufacturing. In order to analyse product qualities online and at the very point of interest, automated monitoring systems must satisfy strong requirements in terms of miniaturization, energy autonomy, and real time operation. Toward this goal, we present the first implementation of artificial taste running on neuromorphic hardware for continuous edge monitoring applications. We used a solid-state electrochemical microsensor array to acquire multivariate, time-varying chemical measurements, employed temporal filtering to enhance sensor readout dynamics, and deployed a rate-based, deep convolutional spiking neural network to efficiently fuse the electrochemical sensor data. To evaluate performance we created MicroBeTa (Microsensor Beverage Tasting), a new dataset for beverage classification incorporating 7 h of temporal recordings performed over 3 days, including sensor drifts and sensor replacements. Our implementation of artificial taste is 15× more energy efficient on inference tasks than similar convolutional architectures running on other commercial, low power edge-AI inference devices, achieving over 178× lower latencies than the sampling period of the sensor readout, and high accuracy (97%) on a single Intel Loihi neuromorphic research processor included in a USB stick form factor.

Operational modal analysis of a multi-span skew bridge using real-time wireless sensor networks

2010 ◽  
Vol 17 (13) ◽  
pp. 1952-1963 ◽  
Author(s):  
MJ Whelan ◽  
MV Gangone ◽  
KD Janoyan ◽  
R Jha
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Sampling Rate ◽  
Sensor Data ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Radio Waves ◽  
Operational Mode ◽  
Ambient Vibration Testing ◽  
Output Only

A large-scale field deployment of high-density, real-time wireless sensors networks for the acquisition of local acceleration measurements across a medium length, multi-span highway bridge is presented. The advantages, performance characteristics, and limitations of employing this emerging technology in favor of the traditional cable-based acquisition systems are discussed in the context of the in-service instrumentation and ambient vibration testing of a multi-span bridge. Of particular highlight in this study is the deployment of a large number of stationary rather than reference-based accelerometers to uniquely permit simultaneous acquisition of vibration measurements across the structure and thereby ensure consistent temperature, ambient vibration, and traffic loading. The deployment consisted of 30 dual-axis accelerometers installed across the girders of the bridge and interfaced with 30 wireless acquisition and transceiver nodes operating in two star topology networks. Real-time wireless acquisition at a per channel sampling rate of 128 samples per second was maintained across both networks for the specified test durations of 3 min with insignificant data loss. Output-only system identification of the structure from the experimental data is presented to provide estimates of natural frequencies, damping ratios, and operational mode shapes for 19 modes. The analysis of the structure under test provides a unique case study documenting the measured response of a multiple-span skewed bridge supported by elastomeric bearings. The feasibility of embedded wireless instrumentation for structural health monitoring of large civil constructions is concluded while highlighting relevant technological shortcomings and areas of further development required. In particular, previously undocumented obstacles relating to radio transmission of the sensor data using low-power 2.4 GHz wireless instrumentation, such as the effect of solid piers within the line-of-sight and the reflection of the radio waves on the surface of the water, are discussed.

Real-time signal processing in field programmable gate array based digital gamma-ray spectrometer

2020 ◽  
Vol 91 (10) ◽  
pp. 104707
Author(s):  
Yinyu Liu ◽  
Hao Xiong ◽  
Chunhui Dong ◽  
Chaoyang Zhao ◽  
Quanfeng Zhou ◽  
...  
Keyword(s):  
Signal Processing ◽  
Real Time ◽  
Field Programmable Gate Array ◽  
Gamma Ray ◽  
Time Signal ◽  
Gamma Ray Spectrometer ◽  
Field Programmable ◽  
Gate Array ◽  
Real Time Signal Processing

Accelerating laser processes with a smart two-dimensional polygon mirror scanner for ultra-fast beam deflection

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Florian Roessler ◽  
André Streek
Keyword(s):  
Energy Distribution ◽  
Real Time ◽  
Laser Processing ◽  
High Speed ◽  
Beam Deflection ◽  
Two Dimensional ◽  
Heat Accumulation ◽  
Field Programmable ◽  
Drill Holes ◽  
Average Laser

Abstract In laser processing, the possible throughput is directly scaling with the available average laser power. To avoid unwanted thermal damage due to high pulse energy or heat accumulation during MHz-repetition rates, energy distribution over the workpiece is required. Polygon mirror scanners enable high deflection speeds and thus, a proper energy distribution within a short processing time. The requirements of laser micro processing with up to 10 kW average laser powers and high scan speeds up to 1000 m/s result in a 30 mm aperture two-dimensional polygon mirror scanner with a patented low-distortion mirror configuration. In combination with a field programmable gate array-based real-time logic, position-true high-accuracy laser switching is enabled for 2D, 2.5D, or 3D laser processing capable to drill holes in multi-pass ablation or engraving. A special developed real-time shifter module within the high-speed logic allows, in combination with external axis, the material processing on the fly and hence, processing of workpieces much larger than the scan field.

scholarly journals An Improved Multipath Mitigation Method and Its Application in Real-Time Bridge Deformation Monitoring

2021 ◽  
Vol 13 (12) ◽  
pp. 2259
Author(s):  
Ruicheng Zhang ◽  
Chengfa Gao ◽  
Qing Zhao ◽  
Zihan Peng ◽  
Rui Shang
Keyword(s):  
Real Time ◽  
Sampling Rate ◽  
Threshold Value ◽  
Deformation Monitoring ◽  
Success Rates ◽  
Multipath Mitigation ◽  
Mode Decomposition ◽  
Observation Noise ◽  
Original Observation ◽  
Better Than

A multipath is a major error source in bridge deformation monitoring and the key to achieving millimeter-level monitoring. Although the traditional MHM (multipath hemispherical map) algorithm can be applied to multipath mitigation in real-time scenarios, accuracy needs to be further improved due to the influence of observation noise and the multipath differences between different satellites. Aiming at the insufficiency of MHM in dealing with the adverse impact of observation noise, we proposed the MHM_V model, based on Variational Mode Decomposition (VMD) and the MHM algorithm. Utilizing the VMD algorithm to extract the multipath from single-difference (SD) residuals, and according to the principle of the closest elevation and azimuth, the original observation of carrier phase in the few days following the implementation are corrected to mitigate the influence of the multipath. The MHM_V model proposed in this paper is verified and compared with the traditional MHM algorithm by using the observed data of the Forth Road Bridge with a seven day and 10 s sampling rate. The results show that the correlation coefficient of the multipath on two adjacent days was increased by about 10% after residual denoising with the VMD algorithm; the standard deviations of residual error in the L1/L2 frequencies were improved by 37.8% and 40.7%, respectively, which were better than the scores of 26.1% and 31.0% for the MHM algorithm. Taking a ratio equal to three as the threshold value, the fixed success rates of ambiguity were 88.0% without multipath mitigation and 99.4% after mitigating the multipath with MHM_V. The MHM_V algorithm can effectively improve the success rate, reliability, and convergence rate of ambiguity resolution in a bridge multipath environment and perform better than the MHM algorithm.

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