Computer-Controlled Experimental Vehicle
on Track

The CVDC Experimental Vehicle was taken out on the test track at QinetiQ in Chertsey, for the first time during the last week of October. The aims of the tests were to commission the trailer running gear as well as the instrumentation, electronic systems, controller area network (CAN) and computer controllers.

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1. Successful commissioning of the trailer suspensions, brakes, ABS and air suspension height levelling systems.

2. Commissioning of computer network system and communications protocols between the Global and Local controller computers.

3. Successful logging of test data from 28 channels of instrumentation, mounted on the tractor and semi-trailer. This data was digitised at 250Hz on two different Local Controllers (one on each vehicle unit), and transferred via the CAN to the Global Controller where it was analysed and logged. The sensors included suspension displacement transducers; pressure transducers; lateral and longitudinal accelerometers; strain gauges; yaw and roll rate sensors, steering and articulation angle sensors; and vehicle speed and sideslip. (This system has the ability to log 80 or more sensor channels at 250Hz over CAN.)

4. Steady-state handling tests performed on the skid pan, with the trailer anti-roll systems set in both the 'locked' (stiff passive) mode and the 'unlocked' (soft passive) mode.

5. The first simple suspension control tests were performed. In these tests, the control mode of the anti-roll bars was switched from 'locked' to the 'unlocked' mode, while the vehicle was in a steady turn. The sensors measured the transient effects on the handling behaviour of the vehicle. This required control messages to be sent from the Global Controller to the Local Controllers while sensor data was transferred in the opposite direction.

   Nearly all of the key objectives of the tests were achieved, and the project moved one large step closer to fruition. Our thanks to the staff at QinetiQ for their help and use of facilities throughout the week.

   D Cebon
   8 November, 2001