期刊名称:Lecture Notes in Engineering and Computer Science
印刷版ISSN:2078-0958
电子版ISSN:2078-0966
出版年度:2018
卷号:2233&2234
页码:629-634
出版社:Newswood and International Association of Engineers
摘要:To measure a vector field it is needed to use a field
sensor. This type of sensors measures both the direction and
magnitude of a vector, e.g., magnetometers and accelerometers.
These devices divide the physical space in two or three
dimensions so that the sensor detects the components of the
field in two or three axes respectively.
Usually, before using the data acquired from this sort of
sensors, it is necessary to do a previous mathematical
processing to guarantee that the measured field is truly
proportional to the actual vector field. This is called
calibration.
This work was developed for the self-calibration of a twodimensional
magnetometer used in a Robotracer for robotics
competitions. However, the calibration can be done for any
two-dimensional field sensor. For the proposed process, the
sensor must be surrounded by a constant field because the
calibration algorithm adjusts the sensor data using the fact
that the magnitude of the field is constant.
The algorithm uses a linear model for the calibration of the
sensor data. Then, to find the optimal values for the calibration
constants, a Standard Gradient Descent algorithm was
implemented.
The results of the implementation for different devices are
presented in this work. It is showed the results for three
accelerometers, MPU-6050, ADXL345 and FALCON-GX
digital IMU. Time of execution is analyzed for each device
using the soft-core processor NIOS II. The processor was
running at 100 MHz of clock with 50% duty cycle. It is inside
the FPGA EP4CE22F17C6N, Altera´s Cyclone IV family. All
this work was done using the DE0-Nano development board.