Inertial measurement units (IMUs) for applications such as automobiles and handheld positioning systems have grown rapidly in recent years. However, lower volume industrial applications have different requirements. Instead of non-calibrated, analog output, industrial users want more integration and a calibrated output. “Since many motion sensors are shipped without calibration, their performance can be sensitive to changes in voltage, temperature, vibration and the effects of other sensors in the IMU,” says Andy Garner, product line director for iSensor intelligent sensor products, Analog Devices.
Analog Devices' ADIS16355 inertial measurement unit (IMU) solves these problems with factory calibration, cross compensation and precision alignment to correct for all significant electrical, positional and motion influences. A combination of mechanical design for the initial phase and then final electrical calibration ensures precision axial alignment to get as close as possible to an ideal 90-degree position.
A serial peripheral interface (SPI) accesses data from all the sensors and allows tuning of motion sensing for a specific application's dynamic range. Internal digital filtering tunes out any drift in the gyroscopes. The ADIS16355 has a full-temperature-range calibration from -40 to 85C and bias temperature stability of 0.005 degree/sec/degrees C.
The system's programmable features include in-system auto-bias calibration, digital filtering and sample rate, self-test, power management and condition monitoring. The self-test feature provides the ability to electrically drive the six structures and verify each is working properly. A simple command initiates the self-test for the three accelerometers and the three gyros.
To simplify design a Programmable, Triple Axis Gyro & Accelerometer Evaluation Board provides access to the IMU using standard 2 x 2 x 6-mm connectors and a Tri-Axis Inertial Sensor PC Evaluation System provides a PC-based evaluation system.
Ideal applications for the industrial IMU include stabilizing an aerial camera in motion picture production, controlling a robotic arm in factory automation and ensuring stability in a prosthetic limb.