移动机器人激光测距仪性能综述

对当前移动机器人上常用的激光测距仪的性能研究进行了全面的总结。分析了检测SICK、Perceptron、Explorer等常用激光测距仪各方面特性的各种实验结果。根据影响激光测距仪测量性能的方式,把激光测距仪的时变特性、角度偏移、数据传输影响、混合象素现象、色度亮度干扰现象、辐射干扰现象等,分为内因和外因两大类进行了分类讨论。

Strain Rate-Dependent Compressive Deformation Behavior of Nd-Based Bulk Metallic Glass

Compressive deformation behavior of the Nd60Fe20Co10Al10 bulk metallic glass was characterized over a wide strain rate range (6.0 x 10(-4) to 1.0x10(3) s(-1)) at room temperature. Fracture stress was found to increase and fracture strain decrease with increasing applied strain rate. Serrated flow and a large number of shear bands were observed at the quasi-static strain rate (6.0 x 10(-4)s(-1)). The results suggest that the appearance of a large number of shear bands is probably associated with flow serration observed during compression; and both shear banding and flow serration are a strain accommodation and stress relaxation process. At dynamic strain rates (1.0 x 10(3) s(-1)), the rate of shear band nucleation is not sufficient to accommodate the applied strain rate and thus causes an early fracture of the test sample. The fracture behavior of the Nd60Fe20Co10Al10 bulk metallic glass is sensitive to strain rate.

A 10-bit 50-MS/s sample-and-hold circuit with low distortion sampling switches

A fully-differential switched-capacitor sample-and-hold (S/H) circuit used in a 10-bit 50-MS/s pipeline analog-to-digital converter (ADC) was designed and fabricated using a 0.35-μm CMOS process. Capacitor fliparound architecture was used in the S/H circuit to lower the power consumption. In addition, a gain-boosted operational transconductance amplifier (OTA) was designed with a DC gain of 94 dB and a unit gain bandwidth of 460 MHz at a phase margin of 63 degree, which matches the S/H circuit. A novel double-side bootstrapped switch was used, improving the precision of the whole circuit. The measured results have shown that the S/H circuit reaches a spurious free dynamic range (SFDR) of 67 dB and a signal-to-noise ratio (SNR) of 62.1 dB for a 2.5 MHz input signal with 50 MS/s sampling rate. The 0.12 mm~2 S/H circuit operates from a 3.3 V supply and consumes 13.6 mW.