从基于LSM6DSL的车辆RPM技术仪表恢复的振动数据中应用的FFT无法读取中频值

大家好！
我们正在开发基于LSM6DSL的车辆RPM技术仪表，STM32L431KCU6微控制器以80 Mhz的速度运行。我们的目标是通过对从中收集的单轴振动数据应用FFT F（max）来读取RPM
LSM6DSL
加速度计的范围为F = 20 Hz至200 Hz。此处附有双层PCB板的图片供您参考。
FFT的设置是
设置：ODR = 6000 Hz，FFT样本= 256，幅度= 200mg，满量程= + -2g
接收的FFT F（max）值是25Hz，50Hz，76Hz，101Hz，127Hz，并且不像连续的25,26,27,28，但在两个连续值之间得到近似25Hz的分辨率
而我们从基于MEMS加速度计的市售RPM技术仪表中获得连续范围内的Fmax值，因此我们无法将车辆的加速器保持在车辆所需的RPM以用于车辆测试目的。请使用如果我们犯了一些错误或建议我们错在哪里，建议FHz范围为20Hz到200Hz的最佳FFT参数设置。
https://community.st.com/tags♯/?tags=vibration
https://community.st.com/tags♯/?tags=mems%20accelerometer
我希望我们为这样的应用选择了正确的ST MEMS部件，或者建议新的另一个。
提前致谢！
谢谢和最诚挚的问候，
VK Verma

#mems-accelerometer #vibration

以上来自于谷歌翻译

以下为原文

Hi to All !
We are working on LSM6DSL based vehicle RPM Techno-meter with STM32L431KCU6 micro controller running at the speed of 80 Mhz. Our target is to read RPM by applying FFT F(max) on the single axis vibration data collected from
LSM6DSL
accelerometer from the range of F = 20 Hz to 200 Hz.The picture of the double layer PCB board is attached herewith for your reference.
The Setting for FFT are

Settings: ODR = 6000 Hz, FFT Samples = 256, Magnitude = 200mg, Full scale = +-2g
FFT F(max) values received are 25Hz, 50Hz, 76Hz, 101Hz, 127Hz and not like 25,26,27,28 in continuous but getting with approximate resolution of 25Hz between two consecutive values
whereas we are getting Fmax values in continuous range from one of the commercially available RPM techno-meter based on MEMS accelerometer and due to this we are unable to hold the accelerator of the vehicle at the desired RPM of the vehicle for vehicle testing purposes.

Please suggest the best FFT parameter settings for the Fmax range of 20Hz to 200 Hz if we are making some mistake or suggest where we are wrong.
https://community.st.com/tags♯/?tags=vibration
https://community.st.com/tags♯/?tags=mems%20accelerometer
I hope we have selected right ST MEMS part for such application or suggest new another one.
Thanks in advance!
Thanks and Best Regards,
VK Verma

#mems-accelerometer #vibration

曾玲娟

2018-10-19 11:31:42

您能否分享您的FFT结果和预期RPM的图片。
如果您获得多个一次谐波频率（在您的情况下为25Hz，应该是1500 RPM），我认为这是正确的。

以上来自于谷歌翻译

以下为原文

Can you please share picture of your FFT results and expected RPM.
I think it is correct if you get multiple of first harmonic frequency (25Hz in your case, which should be 1500 RPM).

李丽

2018-10-19 11:49:54

你好Miroslav，
在我们的观察中，我们得到的RPM大约是F max的30倍，这就是为什么25Hz接近750 RPM并且在车辆转速计中观察到的相同。现在请帮助我们在两次连续读数之间减少25 Hz因数，这样我们就能达到+/- 10 rpm的RPM分辨率。
非常感谢您的支持。
谢谢，敬意，
VK Verma

以上来自于谷歌翻译

以下为原文

Hi Miroslav,
In our observation, we are getting RPM which is roughly 30 times of F max and that is why 25Hz is close to 750 RPM and the same is observed in the vehicle tachometer. Now please help us to reduce 25 Hz factor between two consecutive readings so that we will be able to achieve RPM resolution of +/-10 rpm.
Your support will be highly appreciated.
Thanks and Best regards,
VK Verma

李丽

回帖（2）

曾玲娟

李丽

相关问答

请问LSM6DSL和LSM6DS3的兼容性如何？

LSM6DSL与LSM6DS3之间的引脚是如何兼容的呢

LSM6DSL传感器读取z轴数据一直有偏差是什么问题呢

LSM6DSL读错误？

如何在LSM6DSL中激活传感器集线器模式

LSM6DSL Fifo数据集损坏

怎么用传感器上的引脚int1通过中断读取lsm6dsl数据

LSM6DSL使用不活动中断而不自动降低采样率

LSM6DSL的原始数据为什么乘以灵敏度？

LSM6DSL零g电平偏移精度

20万+工程师都在用，免费PCB检查工具