Amplifiers help optimise students' suspensions

Edited by the Engineeringtalk editorial team Jul 19, 2006

Strain gauge amplifiers supplied by Sensor Techniques are playing a small, yet important role, in the ongoing development of Cardiff University's Formula Student racing car.

Strain gauge amplifiers supplied by Sensor Techniques are playing a small, yet important role, in the ongoing development of Cardiff University's Formula Student racing car.

Although started only three years ago, the Cardiff racing team achieved an excellent second place in the UK and 8th overall in the world in 2005.

Formula Student, a European venture, was launched in the UK in 1998 to provide engineering students with an invaluable insight into motor sport and to provide the industry with high calibre graduates with appropriate experience.

The event, which now attracts more than 60 teams from all over the world, is highly contested and challenges students to produce a single seat racing car designed specifically for use in Autocross events.

To meet this challenge, during the final year of studies young graduates are exposed to marketing, time management, budgeting, presentation skills, and other management issues, as well as analytical and conceptual design.

No other type of competition does this and no other engineering project generates so many enthusiastic and well-trained individuals.

Six of the LAU63 amplifier modules are enabling the Cardiff racing team to analyse the loads in the suspension of their latest car.

The amplifiers are connected to sets of strain gauges which measure the loads in the four suspension pushrods and the two steering tie-rods.

The readings from the amplifiers are transmitted to the onboard data logging system.

This information is then being used to analyse the performance and effects of damper adjustments on the tyre contact patch loads and steering loads during cornering manoeuvres.

The features of the LAU make this cost effective unit ideal for such onboard vehicle applications and the module is designed for force measurement applications in both tension and compression.

Linearity is better than 0.01% and the selectable low pass filter between 3.3kHz and 3.3Hz allows faster force signals to be accepted and amplified, whilst ignoring spurious readings from unwanted vibration.

One of the main problems with vehicle applications is the available power supply.

The LAU can operate from any varying raw voltage supply between 12 and 24V DC.

From this it generates a highly stable bipolar voltage output of 0 to +/-10V.

This proved to be particularly beneficial for Cardiff racing who need to measure both tensile and compressive forces in the suspension.

As vehicle dynamics project leader Richard Elliott highlights: "When we were looking for suitable amplifiers, we found other manufacturers' units did not provide this important facility".

"To overcome this shortcoming we would have had to spend time and money to build our own split voltage rail".

"The selectable zero offset and gain capabilities of the LAU have also shown to be very useful".

"Sensor Techniques have proved to be very knowledgeable and helpful with this part of the project".

The LAU is part of Sensor Techniques' extensive range of weight amplifiers, weight controllers, digital displays, load cells and mounting assemblies.