Magnetostrictive Sensor System Helps High-Performance Car Brake Quickly
- Created: Wednesday, 01 August 2007
The Bugatti Veyron is the world’s fastest street-legal motor vehicle, a high-end passenger car that can reach speeds of more than 200 miles per hour. These high speeds require extra braking power, which comes from raising an aerodynamic rear wing and generating additional braking forces. The Veyron can decelerate from 230 mph to 0 in only 7.5 seconds, largely due to the extra down force achieved with the rear wing, which is raised within 0.4 seconds to a 55° angle.
Bugatti engineers needed a compact position sensor that was rugged, accurate, and reliable for use in the operation of the rear wing. MTS Systems Corp. Sensors Division (Cary, NC) supplied two Model MS mobile hydraulic Temposonics® magnetostrictive sensors for height adjustment and angular adjustment monitoring control.
The 55° angle is measured by the sensor, which is directly fitted into the hydraulic cylinder. The sensor housing and measuring pipe are made of stainless steel, and environmental factors such as dust, water, and temperature variations do not affect the measured signal. The housing contains the sensor’s electronic components, which are shielded from electromagnetic interference (EMI).
The linear position sensor is based on the principle of magnetostrictive measurement. The sensor doesn’t require calibration or re-setting of reference points, due to its non-contact technology. To determine position, an integrated position magnet generates a sound wave as a measuring signal by torsion in the sensing element mounted in the hydraulic cylinder. The pulse is propagated in the sensing element at ultrasonic speed and is converted into a standard output signal by means of run-time measurement. A direct contact between the position magnet and the measuring element is not necessary, so the principle of operation is non-contact and without wear. A specific mode of signal evaluation, which virtually excludes signal interference, is an additional feature of the sensor.
The encapsulated, pressure-proof waveguide is installed directly in the hydraulic-style piston rod. The position magnet is the only mobile part, and is mounted in the bottom of the piston. It provides non-contact signaling to the waveguide. Conditioned standard signals, which do not require additional evaluation circuitry, are output by the electronics integrated in the sensor housing.
For more information on the Temposonics magnetostrictive sensors, visit http://info.hotims.com/10974-325.