Datasheet

Functional Overview
6
2
Functional Overview
2.1 Introduction
Sensor fusion encompasses a variety of techniques that:
•
Trade off strengths and weaknesses of the
be calculated using the individual components
•
Improve the quality and noise level of computed results by taking advantage of:
—
Known data redundancies between sensors
—
Knowledge of system transfer
The Freescale Sensor Fusion Library for Kinetis (Fusion Library) supports several combinations of
sensors. In general, performance improves as more sensors are added to the system. The primary
function of the library is t
o compute orientation of a sensor subsystem relative to a global frame of
reference.
Orientation can be expressed in a number of different ways:
•
Tilt from vertical (may also be expressed as roll + pitch)
•
Compass heading (geomagnetic north)
• Full 3D rotation
from a global frame in any of the following forms:
— Rotation matrix
—
Rotation vector (3D axis of rotation and rotation about that axis)
— Quaternion
—
Euler angles (roll, pitch and yaw)
For additional portability details and guidelines refer to the
User Guide which is part of the
Sensor Fusion Library
source code form and
is designed to sit on top of board abstractions provided by Processor Expert and
MQXLite. The C source
and header files in the Sources directory of the project templates are board and
MCU independent.
Board dependencies are included as compile time options.
does not bring out the GPIO, I2C or UART needed, the board will not be compati
and therefore will not be supported by Processor Expert.
2.2
Accelerometer Only
An accelerometer measures linear acceleration minus gravity. If linear acceleration is zero, this sensor
can be used to measure tilt from vertical, roll and p
configuration.
Figure
Freescale
Sensor Fusion Library for Kinetis
Freescale
Functional Overview
Sensor fusion encompasses a variety of techniques that:
Trade off strengths and weaknesses of the
various sensors to compute something more than can
be calculated using the individual components
Improve the quality and noise level of computed results by taking advantage of:
Known data redundancies between sensors
Knowledge of system transfer
functions, dynamics and kinematics
The Freescale Sensor Fusion Library for Kinetis (Fusion Library) supports several combinations of
sensors. In general, performance improves as more sensors are added to the system. The primary
o compute orientation of a sensor subsystem relative to a global frame of
Orientation can be expressed in a number of different ways:
Tilt from vertical (may also be expressed as roll + pitch)
Compass heading (geomagnetic north)
from a global frame in any of the following forms:
Rotation vector (3D axis of rotation and rotation about that axis)
Euler angles (roll, pitch and yaw)
For additional portability details and guidelines refer to the
Freescale Se
nsor Fusion for Kinetis MCUs
Sensor Fusion Library
installation. The Fusion Library is available in
is designed to sit on top of board abstractions provided by Processor Expert and
and header files in the Sources directory of the project templates are board and
Board dependencies are included as compile time options.
If a particular board
does not bring out the GPIO, I2C or UART needed, the board will not be compati
ble with the software
and therefore will not be supported by Processor Expert.
Accelerometer Only
An accelerometer measures linear acceleration minus gravity. If linear acceleration is zero, this sensor
can be used to measure tilt from vertical, roll and p
itch. Computation of yaw is not supported by this
Figure
1. Accelerometer only block diagram
Sensor Fusion Library for Kinetis
MCUs, Rev. 0.7, 9/2015
Freescale
Semiconductor, Inc.
various sensors to compute something more than can
Improve the quality and noise level of computed results by taking advantage of:
The Freescale Sensor Fusion Library for Kinetis (Fusion Library) supports several combinations of
sensors. In general, performance improves as more sensors are added to the system. The primary
o compute orientation of a sensor subsystem relative to a global frame of
nsor Fusion for Kinetis MCUs
installation. The Fusion Library is available in
is designed to sit on top of board abstractions provided by Processor Expert and
and header files in the Sources directory of the project templates are board and
If a particular board
ble with the software
An accelerometer measures linear acceleration minus gravity. If linear acceleration is zero, this sensor
itch. Computation of yaw is not supported by this