Accelerometers for High Accuracy Under Harsh Vibration Conditions

Physical Logic has released the following case study detailing the advantages of its in-plane MEMS architecture in harsh environmental conditions, proving that acceleration, vibration, shock, tilt and rotation in high-g applications can be measured with high accuracy even in the small, light form factors required by drones and Unmanned Aerial Vehicles (UAVs).

MEMS accelerometer advances over the past two decades have opened new opportunities in many areas of motion sensing. With the explosive growth of UAVs, precision requirements for highly dynamic, high-vibration platforms have increased the downward pressure on cost, weight, size, and power. The unique advantages of in-plane MEMS architecture introduced by Physical Logic prove that acceleration, vibration, shock, tilt and rotation in high-g applications can be measured with greater accuracy than previously achievable in small, light form factors.

Many navigation applications require high input acceleration measurements up to 50g and 70g. This can be difficult to achieve without losses in other key performance parameters; thus, requires very deep understanding and careful management of the overall error budget.

One of the main advantages of Physical Logic’s Closed Loop MEMS accelerometers is almost zero Vibration Rectification Error (VRE). This low VRE, for example, is a major advantage for the application of package delivery systems, in which safety is a crucial parameter. As the propeller vibration affects the navigation of a delivery drone, low VRE is critical to avoid any accidents which may cause huge repercussions.

Another interesting application is underground navigation for resource exploitation. With no GPS time, and long measurements underground which include high changes in temperature and harsh vibration conditions, low temperature sensitivity and low VRE sensors are a must.

In 2021 Physical Logic qualified 50g and 70g sensing range Closed Loop MEMS accelerometers and joined the Closed Loop series which already included 15g and 30g accelerometers.

The Figure below shows VRE test results of 6 MAXL-CL-3070, 70g sensing range prototypes that were manufactured to one of our valuable customers.

Random Vibration Test @ 12 gRMS (20-2000 Hz) was performed along 30 minutes (XX axis represents the sensing direction). The compatibility in high vibration environment was proved when all tested accelerometers showed VRE ≤ 3.4 µg/g²RMS.

Although smaller in size, lighter in weight and lower in price, Physical Logic’s unique MEMS technology shows a significant advantage in harsh environmental conditions over traditional quartz pendulum accelerometers.