Page 185 - MEMS Mechanical Sensors

174 Inertial Sensors

Table 8.1 Typical Applications for Micromachined Accelerometers
Application Bandwidth Resolution Dynamic Range
Automotive
Airbag release 0–0.5 kHz <500 mG ±100G
Stability and active 0–0.5 kHz <10 mG ±2G
control systems dc–1 kHz <10 mG 100G
Active suspension
Inertial navigation 0–100 Hz <5 µG ±1G
Seismic activity
Shipping of fragile goods 0–1 kHz <100 mG ±1kG
Space microgravity 0–10 Hz <1 µG ±1G
measurements
Medical applications 0–100 Hz <10 mG ±100G
(patient monitoring)
Vibration monitoring 1–100 kHz <100 mG ±10 kG
Virtual reality (head-mounted 0–100 Hz <1mG ±10G
displays and data gloves)
Smart ammunition 10 Hz to 100 kHz 1 G ±100 kG

there will be a single inertial sensor capable of being used for all applications areas;
rather, all inertial sensors are application specific, which explains the great variety of
sensor types.
For any given application the inertial sensor is part of a larger control system,
whereas the mere information about acceleration or angular motion of a body of
interest is usually of little interest. For example, a gyroscope detects the angular
motion of a car and if this is above a critical level, the safety system will actively
control the steering angle and the brakes at each wheel to prevent the vehicle from
overturning.
Micromachined inertial sensors have been the subject of intensive research for
over two decades since Roylance et al. [1] reported the first micromachined acceler-
ometer in 1979. Since then many authors have published work about various types
of MEMS accelerometer. The development of gyroscopes based on micromachined
silicon sensing elements lags behind by about one decade: the first real MEMS gyro-
scope was reported by Draper Labs in 1991 [2].

Table 8.2 Typical Applications for Micromachined Gyroscopes
Application Bandwidth Resolution Dynamic Range
Automotive
Rollover protection 0–100Hz <1°/sec ±100°/sec
Stability and active 0–100Hz <0.1°/sec ±100°/sec
control systems
–4
Inertial navigation 0–10 Hz <10 °/sec ±10°/sec
Platform stabilization 0–100 Hz <0.1°/sec ±100°/sec
(e.g., for video camera)
Virtual reality (head-mounted dc–10 Hz <0.1°/sec ±100 °/sec
displays and data gloves)
Pointing devices for dc–10 Hz <0.1°/sec ±100°/sec
computer control
Robotics dc–100 Hz <0.01°/sec ±10°/sec