Acceleration Anomaly Detection Method for Sensor Axle Box of Unmanned Vehicle

Detecting the anomaly acceleration of the sensor’s axle box of unmanned vehicles is very important for judging the wear condition of vehicle track and evaluating the state of the track. A capacitive accelerometer is connected with acquisition equipment to collect the information of train axle box’s acceleration change when the vehicle is running; instrument amplifier AD8250 with a digitally programmable gain is selected as system signal conversion chip to realize acceleration signal conversion; sliding variance of axle box’s acceleration of the unmanned vehicle is calculated based on sliding variance statistical analysis method, which is confirmed by time window and distance window. Fixing the width of a sliding window according to the response statistics caused by the line excitation link, the acceleration sliding variance is compared with the standard one to determine whether the acceleration is in an anomaly state. The test results show that the anomaly acceleration of the sensor axle box of the unmanned vehicle detected by the proposed method is consistent with the actual results, which provides a reliable basis for vehicle track condition assessment.

Wireless endovascular nerve stimulation with a millimeter-sized magnetoelectric implant

Implanted bioelectronic devices have the potential to treat disorders that are resistant to traditional pharmacological therapies; however, reaching many therapeutic nerve targets requires invasive surgeries and implantation of centimeter-sized devices. Here we show that it is possible to stimulate peripheral nerves from within blood vessels using a millimeter-sized wireless implant. By directing the stimulating leads through the blood vessels we can target specific nerves that are difficult to reach with traditional surgeries. Furthermore, we demonstrate this endovascular nerve stimulation (EVNS) with a millimeter sized wireless stimulator that can be delivered minimally invasively through a percutaneous catheter which would significantly lower the barrier to entry for neuromodulatory treatment approaches because of the reduced risk. This miniaturization is achieved by using magnetoelectric materials to efficiently deliver data and power through tissue to a digitally-programmable 0.8 mm2 CMOS system-on-a-chip. As a proof-of-principle we show wireless stimulation of peripheral nerve targets both directly and from within the blood vessels in rodent and porcine models. The wireless EVNS concept described here provides a path toward minimally invasive bioelectronics where mm-sized implants combined with endovascular stimulation enable access to a number of nerve targets without open surgery or implantation of battery-powered pulse generators.

Bio-Inspired Radio-Frequency Source Localization Based on Cochlear Cross-Correlograms

This paper describes a bio-inspired radio frequency (RF) scene analysis system based on cross-correlating the outputs of two single-chip RF spectrum analyzers. The latter are implemented using digitally-programmable “RF cochlea” chips (in 65 nm CMOS) that integrate a transmission-line active cochlear model, consisting of 50 parallel exponentially-spaced stages for analyzing the radio spectrum from 1.0 to 8.3 GHz, together with an output encoding network. The encoders convert the analog outputs of all cochlear stages into parallel delta-sigma (Δ-Σ) modulated digital signals for real-time demodulation and analysis by a digital back-end processor. These outputs can also be multiplied with each other to generate cochlear correlation matrices (known as cross-correlograms). Simulation results demonstrate the use of cross-correlograms for wide-range time-delay estimation and real-time multi-source localization at different frequencies and input signal-to-noise (SNR) ratios. Over-the-air measurement results from an experimental two-channel RF scene analysis prototype confirm the use of such time-delay estimates, which are analogous to interaural time differences (ITDs) in the auditory system, for azimuthal source localization at 3.4 GHz. In addition, differences in received signal strength at the two cochleas, which are analogous to interaural level differences (ILD) in biology, are also used to localize RF sources.