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6-axis motion tracking sensor

6-axis motion tracking sensor

Reliable motion sensor data is crucial for modern automation.

Whether precision agriculture, construction machinery, drones, automated guided vehicles, robots or industrial motors - motion tracking sensors monitor every type of position change, which is evaluated in a corresponding circuit.

Incorrectly executed movements lead to more than just sore muscles in automation. Especially in harsh environments with vibrations and large temperature fluctuations, these measurements must be extremely accurate as well as error-tolerant.

And that's where a motion sensor comes into play that can precisely measure accelerations as well as angular velocities. TDK-InvenSense's ICM-42605 is a 6-axis motion sensor that combines a 3-axis gyroscope and a 3-axis accelerometer in a small 2.5 x 3 x 0.91 mm (14-pin LGA) package.

What flies and moves here also arrives safely.

Inertial Measurement Unit (IMU)

TDK's motion sensors detect the motion and rotation rate of a moving object simultaneously. The manufacturer refers to this as an inertial measurement unit.

In inertial sensors (or inertial sensors), the measuring element is a mass on which external forces produce a change in velocity or direction. Accelerometers measure AC and DC accelerations along three orthogonal axes. Gyroscopes measure AC and DC angular velocities along three orthogonal axes. The three motion sensors mentioned here are also referred to as MEMS sensors. These are components that have a micro-electro-mechanical system (MEMS). So much for the explanation of terms.

The following different combinations of axes within the motion sensors can be realized in one chip at TDK-InvenSense:

6 axes Family of motion sensors with 3-axis gyroscopes and a 3-axis accelerometer on one chip
7 axes Combines a 6-axis IMU and a MEMS barometer sensor
9 axes Combination of a 3-axis gyroscope, a 3-axis accelerometer and a 3-axis compass on one chip
3 axes Separate 3-axis gyroscope and 3-axis accelerometer family of components
2 axes Two-axis gyroscopes for 2-dimensional interfaces
1 axes Mount-specific single-axis gyroscope for basic motion detection

The four most important parameters of the IMU are:

1. Offset

Accelerometer and gyroscope outputs under stable conditions (no motion applied). The unit is dps (degrees per second) for the gyroscope and g for the accelerometer.
TCO or temperature CO coefficient is the deviation of the offset from the temperature. The unit is dps/C for the gyroscope and mg/C for the accelerometer.


Full-scale range

(Full-Scale Range FS)

This parameter defines the maximum measuring range for the component. The unit is dps for the gyroscope and g for the accelerometer.
FS of the gyroscope is normally up to 2000dps and FS of the accelerometer is up to 16g. FS is user selectable from a predefined set of values. The output signal of the gyroscope and accelerometer will saturate when the physical input pulse exceeds the FS value.

3. Sensitivity

Sensitivity refers to the ADC resolution (#_bits) and defines the number of output changes per unit of input.
Sensitivity = 2*FS / (2^#_bits)
The unit of sensitivity is #LSB/dps for the gyroscope and #LSB/g for the accelerometer.
Sensitivity versus temperature is the change in sensitivity versus temperature. The unit is % of the nominal value for gyroscope and accelerometer.

4. Noise

The noise is an unwanted and indistinguishable signal superimposed on the sensor output. The unit is RMS, which represents the standard deviation of the noise.

RMS defines the sensor resolution and represents the smallest detectable change at the Input.

The main two IMU are the ICM-42605 and ICM42688-P 6-axis sensors:

ICM-42605 16-bit Accelerometer ±2 g to ±16 g
19-bit Gyroscope ±15,6 dps to ±2000 dps
ICM42688-P 18-bit Accelerometer ±2 g to ±16 g
19-bit Gyroscope ±15,6 dps to ±2000 dps

The applications here can be very diverse, such as robotics, drones, medical applications, smart home, security devices, sports, AR glasses, smartphones, wearables.

For Automotive
TDK MEMS sensors are tested for reliability according to AEC-Q100. PPAP and qualification data can be provided upon request. They have been specifically developed or qualified and tested for the automotive market to meet the special requirements here. They support the rapid growth in comfort, infotainment, telematics, Advanced Driver Assistance Systems (ADAS) and other technological features for the automobile.

For industry
Special industrial variants of MEMS sensors are suitable for precision agriculture, construction equipment, drones, automated guided vehicles (AGVs), robots and industrial motors.
Motion sensor data is critical for automation, efficiency improvement and monitoring in these applications. Ideal for precise measurements in harsh environments with vibrations and large temperature fluctuations. TDK offers unique functions here, such as the fault-tolerant motion sensing solution.

Evaluation board for quick start
The matching evaluation board is available from stock GLYN for the various MEMS motion sensors.
The platform, which is based on the Microchip G55 MCU, can be used to quickly evaluate and develop ICM-42605-based solutions. The DK-42605 has an integrated debugger, eliminating the need for external tools to program or debug the G55 MCU.
The development kit comes with the necessary software, including InvenSense Motion Link, a GUI-based development tool, and integrated motion drivers for the ICM-42605.

Do you have further questions about the product and evaluation board?
Then we recommend our informative GLYN-Talk SEN-006 on this topic.
Book your individual appointment here - the GLYN-Talk is of course free of charge and without obligation for you.

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