Car Shaker – Closed Loop Control with DSP

f1car

Take an F1 car, a bit like this one and some hydraulic actuators like this, then control them from a DSP card like this one.

Related Products
Skills Used
  • Digital Signal Processing algorithms
  • Microsoft C++ under Windows
  • DLL interface to Labview

Outline

Back in 1999 until 2003 we worked with Conway Young at one of the leading Formula 1 teams to develop a custom test system for car chassis testing. That team has changed name many times and in 2014 has enjoyed great success in the sport. The teams all record acceleration data on the car in the XYZ plane as it laps the track, and then like to be able to “replay” that data onto a chassis back at the factory. This requires the use of hydraulic jacks to apply the forces on the various points of the chassis, and control electronics to drive the jacks. At the heart of the system is a servo loop controller using analogue to digital conversion, DSP and digital to analogue conversion which is where we came in.

Servo Loop Control

Innovative Integration have always had key products for PC and standalone servo loop control. They utilise floating point DSP’s and closely coupled multi-channel simultaneous, low latency data acquisition. The first system was built using the M67 and a quad Adc and Dac module called the A4D4. This products are still made for existing customers but they are not recommended for new designs. The flexibility of the Omnibus IO range meant that when larger systems were later built, they were sometimes based on two modules or the 16 channel Servo16 module.

Custom Real Time Software

We worked with Conway to develop custom real time software so that his Labview based front end was able to control and monitor variables in the DSP, and stream data to the DSP to facilitate real time replay of track data. This meant that the team were able to develop their tests without sharing their ideas with their competitors.

Modern Cards

FPGA’s have largely replaced digital signal processors for closed loop control, and so the products to consider for building a similar system today are the X3-A4D4 and the X3-Servo. These both offer a Spartan3A DSP FPGA, low latency A/D & D/A, clock generation and x1 lane to the host processor for streaming and control.