Estrous detection intensity and accuracy and optimal timing of insemination with automated activity monitors for dairy cows

The objectives of this observational study were to assess the ability of automated activity monitoring (AAM) to detect estrus for first insemination, the accuracy of detection, and the optimum interval from the estrus alert from the AAM system to insemination. Four commercial farms using 1 of 2 commercial AAM systems were studied over 1 yr. Cows were inseminated between 55 and 80 d in milk (DIM) based on AAM only, then by a combination of AAM and timed artificial insemination (AI). Blood progesterone was measured in 1,014 cows at wk 5, 7, and 9 postpartum; purulent vaginal discharge (PVD) was assessed at wk 5; and lameness and BCS at wk 7. Overall, AAM detected 83% of cows in estrus by 80 DIM. Cows that had 3 serum progesterone <1 ng/mL, had PVD, or were both lame and had BCS ≤2.5 has lesser odds of being detected in estrus by 80 DIM (62, 68, and 53%, respectively). Blood samples were collected on the day of 445 AI based on AAM and 323 timed AI. The proportion of cows not in estrus (progesterone >1 ng/mL) on the day of AI was similar between AAM (4 ± 1.8%) and timed AI (3 ± 1.2%). Managers elected, based on subjective criteria, not to inseminate 17% of cows for which an AAM estrus alert was issued, of which 43% were not in estrus. Activity data were extracted from AAM software for 1,399 AI. Onset of estrus was calculated using the same or similar data processing criteria as the AAM system. Producers recorded the time of AI. The interval from onset of estrus to AI was categorized as 0 to 8, 8 to 16, or 16 to 24 h. We found no effect of AAM system on the probability of pregnancy per AI, but noted an interaction of interval with parity. For multiparous cows, the probability of pregnancy per AI was 31%, which did not differ with the interval to AI. For primiparous cows, the odds of pregnancy were greater if AI occurred 0 to 8 h (49%) than 8 to 16 (36%) or 16 to 24 h (31%) after the estrus alert from the AAM. Automated activity monitoring can detect estrus for first AI in just over the length of 1 estrous cycle for over 80% of cows, but the remainder would likely require intervention for timely insemination. For multiparous cows, performing AI based on AAM once per day would not affect pregnancy per AI, but for primiparous cows AI within 8 h of the onset of estrus may be advantageous.     

加速度计横向灵敏度测试方法研究

以加速度计为核心的惯性装置,广泛应用于常规武器飞行参数的测试系统中。随着惯性技术的发展,对惯性装置中加速度计的测试精度要求也越来越高。加速度计的横向输出是影响测试精度的一个重要因素。本文以某型号硅微压阻式加速度计为例,介绍了加速度计横向灵敏度的测试方法,分析了测试数据,给出了该型号加速度计横向灵敏度的测试结果。     

Twin-mass accelerometer optimization to reduce the package stresses

The geometry optimization of a piezoresistive Twin-mass accelerometer is presented. The Twin-mass design is the most sensitive design to the stresses of the package compared to the Cantilever beam and the Quad-beam designs. Finite element simulations are carried out to improve the geometry of the Twin-mass design. Substitution of the perpendicular external beams by lateral external beams reduces the effects of the stresses of the package by a factor of more than 40. Moreover, the sensitivity and the figure of merit of the device can be easily increased.     

基于GPRS&GPS的防盗追踪系统的设计

针对目前野外基站贵重设备缺少有效的无人监管的现状,设计了一种基于GPRS和GPS技术用于远程监控管理野外基站设备的防盗追踪系统.采用重力加速度传感器和GPS分别获取设备的动作信息和位置信息,系统通过动作信息判断设备是否被盗,用户利用GPRS网络收集这些信息,实时监控设备的状态.在设备被盗后采用GPS的位置信息进行跟踪定...     

MEMS压阻式三轴加速度传感器的双路循环电桥检测法

A cycle bridge detection method, which uses a piezoresistive triaxial accelerometer, has been described innovatively. This method just uses eight resistors to form a cycle detection bridge, which can detect the signal of the three directions for real time. It breaks the law of the ordinary independent Wheatstone bridge detection method, which uses at least 12 resistors and each four resistors connected as a Wheatstone bridge to detect the output signal from a specific direction. In order to verify the feasibility of this method, the modeling and simulating of the sensor structure have been conducted by ANSYS, then the dual cycle bridge detection method and independent Wheatstone bridge detection method are compared, the result shows that the former method can improve the sensitivity of the sensor effectively. The sensitivity of the x, y-axis used in the former method is two times that of the sensor used in the latter method, and the sensitivity of the z-axis is four times. At the same time, it can also reduce the cross-axis coupling degree of the sensor used in the dual cycle bridge detection method. In addition, a signal amplifier circuit and adder circuit have been provided, Finally, the test result of the ＂eight-beams/mass＂ triaxial accelerometer, which is based on the dual cycle bridge detection method and the related circuits, have been provided. The results of the test and the theoretical analysis are consistent, on the whole.     

一种用于MEMS电容式加速度计的116dB动态范围CMOS读出电路

A high stability in-circuit reprogrammable technique control system for a capacitive MEMS accelerometer is presented. Modulation and demodulation are used to separate the signal from the low frequency noise. A low-noise low-offset charge integrator is employed in this circuit to implement a capacitance-to-voltage converter and minimize the noise and offset. The application-specific integrated circuit （ASIC） is fabricated in a 0.5 /μm one-ploy three-metal CMOS process. The measured results of the proposed circuit show that the noise floor of the ASIC is -116 dBV, the sensitivity of the accelerometer is 66 mV/g with a nonlinearity of 0.5%. The chip occupies 3.5×2.5 mm2 and the current is 3.5 mA.     

电容式高过载微机械加速度计的设计与实验

针对某些高过载应用场合对微机械加速度计抗冲击能力的要求,设计了一种三轴向抗冲击的梳齿电容式闭环微机械加速度计。通过分析带止档的闭环加速度计冲击响应过程,提出在敏感方向使用悬臂梳齿结构作为柔性缓冲止档可以缓冲冲击过程中微结构间的接触碰撞;在非敏感方向采用结构模态和阻尼分离的设计可减小冲击变形,耗散冲击能量。马歇特锤冲击实验表明,该加速度计能够分别承受3个轴向幅值为13 200g,脉宽约102μs的的加速度冲击,冲击前后偏置漂移在5mV以内。该闭环加速度计在±10g的非线性优于500×10-6,1.5h偏置稳定性为0.27mg。设计的样机基本满足高过载环境下惯性测量的要求。     

两轮小车姿态检测与平衡控制研究

在两轮自平衡小车基础上,完成了基于加速度计和陀螺仪的姿态检测,运用互补滤波算法对数据进行了融合处理,结合PID控制器,实现了小车的自平衡及运动控制。绘制了各传感器及融合后的数据波形,通过实际的运行,表明了该方案可以实现两轮自平衡小车的精确控制。     

Gravimetry based on the method of inertial navigation

A method of spatial gravimetry based on expansion of the functional properties of a three-component inertial navigation system is considered. __________ Translated from Izmeritel’naya Tekhnika, No. 2, pp. 7–9, February, 2006.     

基于微电铸的非硅MEMS加速度传感器

简单介绍了Silicon Design公司开发的非硅MEMS传感器的设计、工艺、输出信号的处理技术.通过巧妙设计和使用铸Ni技术成功地改善了梁的扭摆特性.实测结果表明,10 g产品的输出交流噪声有效值和漂移被分别控制在0.4 mV和4 mV;50 g产品虽然漂移偏大,但其线性系数K2还是达到了10-3～10-4的水准.