MEMS gyroscopes have found their way into a wide range of industrial applications. These industrial-grade MEMS sensors differ from consumer-grade devices in that they can accurately perform in harsh conditions characterized by extreme temperature ranges with constant shocks and vibrations. Industrial applications include platform stabilization in land, air, sea, and space navigation systems, precision agriculture, precision robots, unmanned aerial (UAV) and nautical vehicles, construction equipment, offshore drilling, to name just a few.
The needs of industrial applications differ from consumer applications in substantial ways, and industrial motion sensors are expected to excel in two primary areas: overall high performance as determined by accuracy and precision; and better robustness as determined by ability to withstand harsh environments. With the increasing drive for automation in industrial settings, sensors are additionally expected to meet stricter power, form factor and cost constraints.
One market segment where higher automation is visibly transforming traditional practices is agricultural equipment. Precision agricultural equipment is expected to be a $4.6 billion market by 2020. Equipment control, vehicle steering or navigation, and field/crop management constitute about half of this market (software analytics being the other half). Motion sensing, both angular (using gyros) and linear (using accelerometers) is at the heart of these applications. Precision control of the vehicle and its equipment, based on accurate sensing, translates into improved safety and higher productivity. Typical applications and benefits include:
- Precise navigation of agricultural machines with IMU-assisted GPS helps in optimizing coverage during seeding, fertilizing or insecticidal treatment, thus enhancing yield;
- On uneven terrain typical of large agricultural fields, IMUs enhance vehicle safety by preventing tipping and roll-over;
- Precise terrain data from IMU sensors helps in accurate positioning of the machine’s implements like harvester blade or picker, in order to maximize crop yield.
Selecting the right motion sensor is critical to accomplishing the benefits of automation in all the above applications. As stated earlier, precision and accuracy should be complemented by robustness and ability to withstand the harsh shocks and vibrations inherent in agricultural machines. In order to perform accurately, motion sensors need to be immune to vibrations from sources like humming motors or uneven terrain. Most gyroscopes today are unable to reject these vibrations and shocks, translating these unwanted stimuli into higher noise and shifts in offset performance of the device. Designers have attempted to address the issue by locating the gyroscope in a spot where vibrations are dampened (e.g., within the tractor cab). But in general, it is better not to be forced into limiting where the sensor can go — assuming these external stimuli are even able t0 be appropriately dampened — to obtain a clean signal.
With industrial-grade 3-axis BAW MEMS™ gyroscopes from Qualtré, these issues are eliminated. These unique bulk-acoustic mode resonators operate at 2 – 10MHz frequencies – an order of magnitude higher than flexural mode resonators. Additionally, the high stiffness of the BAW (bulk acoustic wave) disk resonator gives Qualtré gyroscopes considerable inherent immunity to shocks and vibrations, and enables a consistently clean output signal.
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