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Aiming at the high requirements of the experimental equipment for the measurement of high precision quartz flexible accelerometer resolution, the gravity measured by high precision tri-axial accelerometers was subdivided by the tri-axial turntable. Tri-axial quartz flexible accelerometers resolution measurement model was established and general mathematical expression for the resolution measurement was derived. Based on the mathematical expression, the effective angle range that satisfied the measurement condition was given out. Besides, the tri-axial quartz flexible accelerometers resolution measurement process was designed. Within the effective angle range, numerical simulations were performed and the simulation results showed that: the proposed method can theoretically measure tri-axial quartz flexible accelerometers of which the resolution was about 10 −6 g. Then the tri-axial quartz flexible accelerometers resolution repetitive measurement experiments were carried out and the experimental results illustrated that: the difference between the measured value with the theoretical value is within 1µg, which met the requirements for use. In addition, the resolution of tri-axial quartz flexible accelerometers can be measured at one time based on the designed process, demonstrating that the proposed method was valid. INDEX TERMS Tri-axial turntable, tri-axial quartz flexible accelerometers, gravity subdivision, resolution measurement.

No abstract

With the development of vehicle sensors, unmanned driving has become a research hotspot. Positioning is also considered to be one of the most challenging directions in this field. Aiming at the poor positioning accuracy of vehicles under GNSS denied environments, a lane-level positioning method based on inertial system and vector map information fusion is proposed. A dead reckoning model based on optical fiber IMU and odometer is established, and its positioning error is regarded as a priori information. Furthermore, a map matching model based on HMM is built up. Three validation experiments are carried out and experimental results show that the positioning error can be reduced to less than 30 cm when driving for about 7 min, which proves the effectiveness of the proposed method. Our work may provide a reference for the further improvement of positioning for unmanned driving under GNSS denied environments.

In view of the complex structure and inaccurate positioning capabilities of the existing panoramic scanning system, a panoramic scanning device based on a piezoelectric ceramic stack actuator and friction transmission was designed. In our model, the output displacement of the piezoelectric ceramics is amplified by a bridge-type flexure hinge and applied to a shaft by friction to achieve panoramic scanning imaging. The mathematical model of the device was established, and the working characteristics were analyzed. The analysis demonstrated that the linear displacement increment of the shaft is a superposition. A modality simulation was performed, and the simulation results show that the designed device works normally at a frequency of 511.5 Hz. The test results indicated that the displacement of the actuator can reach 6 μm at an input voltage of 100 V. Moreover, the laser scanning results showed that the designed device can perform panoramic scanning imaging, which meets the requirements for use on the high-speed imaging system.