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 to 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 Sensor 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 compatible 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 pitch. 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