Yaw-rate sensor
A yaw-rate sensor is a gyroscopic device that measures a vehicle’s angular velocity around its vertical axis. The angle between the vehicle's heading and vehicle actual movement direction is called slip angle, which is related to the yaw rate.
Types
There are basically two types of Yaw rate sensors: piezoelectric type and micromechanical type.
In the piezoelectric type, the sensor is a "tuning fork"-shaped structure with four piezo elements (two on top and two below). During straight ahead driving, the upper ones produce no voltage as no Coriolis force acts. But in cornering, the rotational movement causes the upper part of the tuning fork to leave the oscillatory plane creating an alternating current voltage which is proportional to the yaw rate and oscillatory speed. The output signal's sign depends on the direction (left or right).
In the micromechanical type, the Coriolis acceleration is measured by a micro-mechanical capacitive acceleration sensor placed on an oscillating element. This acceleration is proportional to the product of yaw rate and the oscillatory velocity, which is maintained electronically at a constant value.
Angular rate sensor
Rate sensors are devices that directly measure angular rate, without integration in conditioning electronics. Gyroscopes also measure angular rate. Generally gyroscopes are able to measure a constant rotation rate, while rate sensors also include devices with a low cut off frequency that is other than zero.
Technologies
Main technologies for rate sensors:
There are two types of MET rate sensors that directly measure angular rate: one that is able to measure constant angular rate (DC sensitive) and one that is not.
A non–DC-sensitive angular rate sensor consists of a toroid filled with a special electrolyte that moves when the device is rotated about its measurement axis. When this happens the electrolyte flows through the sensing element, which is rigidly fixed inside the channel, and the motion is detected. The output signal is proportional to the angular rate due to internal integration that occurs inside of the sensing element. The cutoff frequency for measurements can be as low as 0.005 Hz.
Podcasts:
Latest News for: yaw rate sensor
How Polestar engineers EVs that can handle brutal winters
Ars Technica 25 Mar 2025- 1