10-Bit Single-Slope ADC with Error Calibration for TDI CMOS Image Sensor

A 10-bit single-slope analog-to-digital converter (ADC) for time-delay-integration CMOS image sensor was proposed. A programmable ramp generator was applied to accomplish the error calibration and improve the linearity. The ADC was fabricated in a 180 nm 1P4M CMOS process. Experimental results indicate that the differential nonlinearity and integral nonlinearity were 0.51/-0.53 LSB and 0.63/-0.71 LSB, respectively. The sampling rate of the ADC was 32 kHz.

Towards cognitive navigation:A biologically inspired calibration mechanism for the head direction cell network

To derive meaningful navigation strategies,animals have to estimate their directional headings in the environment.Accordingly,this function is achieved by the head direction cells that were found in mammalian brains,whose neural activities encode one’s heading direction.It is believed that such head direction information is generated by integrating self-motion cues,which also introduces accumulative errors in the long term.To eliminate such errors,this paper presents an efficient calibration model that mimics the animals’behavior by exploiting visual cues in a biologically plausible way,and then implements it in robotic navigation tasks.The proposed calibration model allows the agent to associate its head direction and the perceived egocentric direction of a visual cue with its position and orientation,and therefore to calibrate the head direction when the same cue is viewed again.We examine the proposed head direction calibration model in extensive simulations and real-world experiments and demonstrate its excellent performance in terms of quick association of information to proximal or distal cues as well as accuracy of calibrating the integration errors of the head direction.Videos can be viewed at https://videoviewsite.wixsite.com/hdc-calibration.

New Calibration Technology for Safety Valves of Utility Boiler

Butterfly spring-relief valve, a crucial safety attachment of pressure vessel, is used to prevent pressuresystem from exceeding allowable limit value. Safe, expeditious and accurate calibration of safety valves is consequentlyof vital importance to safe and economic operation of generating units. NSH CALIBRATOR could complete, not only theon-line performance and parameter tests of safety valves within two to five seconds with opening pressure of safetyvalves and steam medium pressure automatically recorded, but also could complete the on-line adjustment of safetyvalves verified unqualified. It saves energy consumption, decreases noise pollution and improves accuracy and efficiencyof safety valve calibration.[

Error analysis and calibration for underwater sound intensity measuring system

Based on measuring the cross-spectrum density of sound pressure between two hydrophones, the facility for underwater sound intensity measurement is investigated and designed. According to the principle of two-hydrophone method for intensity measurement, the error analysis is carried out. Given the method of sound intensity measurement calibration for this underwater sound intensity measurement facility, the uncertainty of intensity measurement by this facility is evaluated. It is shown that the analysis and evaluation are agreeable to the experimental results.

A research on high-temperature permittivity and loss tangent of low-loss dielectric by resonant-cavity technique

Resonant-cavity technique was introduced to measure the permittivity and loss tangent of low-loss dielectrics. The dielectric properties at 9-10 GHz are measured accurately at the temperature up to 800 ℃ by the resonant cavity technique. The only electrical parameters that need to be measured are quality factors （Q） and resonant length （L） of resonant cavity loaded and unloaded with dielectric sample. Moreover, the error caused by thermal expansion effect was resolved by error analysis and experimental calibration.

Rotary axis calculation for five-axis FDM printer using a point-fitting optimization method

This paper presents an optimization method to compute the rotary axes of a 5-axis FDM printer whose A-and C-axes have large deviations relative to the x-and z-directions.The optimization model is designed according to the kinematic model in which a point rotates around a spatial line in the machine coordinate system of the printer.The model considers the A-and C-axes as two spatial lines.It is a two-object optimization model including two aspects.One is that the sum of deviations between the measured and computed points should be small;the other is that the deviations should be uniformly distributed for every measured point.A comparison of the new optimization method with conventional error-compensation methods reveals that the former has higher location accuracy.Using the optimized AC axes,5-axis 3D printing paths are planned for some complex workpieces.Data analysis and printing samples show that the optimized AC axes satisfy 5-axes FDM printing requirements for nozzles with a diameter of 1.0 mm.

Calibration of robotic drilling systems with a moving rail

Industrial robots are widely used in aircraft assembly systems such as robotic drilling systems. It is necessary to expand a robot＇s working range with a moving rail. A method for improving the position accuracy of an automated assembly system with an industrial robot mounted on a moving rail is proposed. A multi-station method is used to control the robot in this study. The robot only works at stations which are certain positions defined on the moving rail. The calibration of the robot system is composed by the calibration of the robot and the calibration of the stations.The calibration of the robot is based on error similarity and inverse distance weighted interpolation.The calibration of the stations is based on a magnetic strip and a magnetic sensor. Validation tests were performed in this study, which showed that the accuracy of the robot system gained significant improvement using the proposed method. The absolute position errors were reduced by about 85%to less than 0.3 mm compared with the maximum nearly 2 mm before calibration.

Consistency correction of echo intensity data for multiple radar systems and its application in quantitative estimation of typhoon precipitation

Calibration error is one of the primary sources of bias in echo intensity measurements by ground-based radar systems.Calibration errors cause data discontinuity between adjacent radars and reduce the effectiveness of the radar system.The Global Precipitation Measurement Kuband Precipitation Radar(GPM KuPR)has been shown to provide stable long-term observations.In this study,GPM KuPR observations were converted to S-band approximations,which were then matched spatially and temporally with ground-based radar observations.The measurements of stratiform precipitation below the melting layer collected by the KuPR during Typhoon Ampil were compared with those of multiple radar systems in the Yangtze River Delta to determine the deviations in the echo intensity between the KuPR and the ground-based radar systems.The echo intensity data collected by the ground-based radar systems was corrected using the KuPR observations as reference,and the correction results were verified by comparing them with rain gauge observations.It was found that after the correction,the consistency of the echo intensity measurements of the multiple radar systems improved significantly,and the precipitation estimates based on the revised ground-based radar observations were closer to the rain gauge measurements.

Independent dual beams generated by array element division in integrated optical phased arrays

Optical phased arrays(OPAs)have broad application prospects due to their advanced capability in beamforming and steering.In this work,we achieve independent dual beams in the far field by dividing the array elements of the OPA,with the maximum scanning range reaching 100°.Based on the working principle of OPAs,theoretical considerations of such multibeam generation are presented.A phase data allocation approach for OPAs in the presence of fabrication-induced random phase variation is developed.Simulations of large ensembles of OPAs with various levels of random residual phase errors have been conducted to help analyze the results.This approach can help OPAs realize multi-beams for light detection and ranging(LiDAR).