Roberto Finazzi - V1.0 del 05/09/2002
iArte application for “Formula 1” brake systems test bench.
(shortform)
This test bench is used for statically testing and experimenting the brake systems for “Formula 1” racing cars. Mechanically it is composed by a piston, drived by a brushless motor, that acts directly on the brakes pump like if it was the racing car driver. Lots of sensors check main physical parameters regarding brake system during tests, such as pressures, forces, strains, and so on. The piston that acts on the brake pump can be moved manually or by using an automatic cycle built of a series of elementary steps. Each step must be assigned a space-time, force-time or pressure-time ghaph that must be executed by the piston acting on the whole brake system. During the automatic cycle the values of the physical parameters read from the sensors are sampled, digitally filtered, linearized, and saved on a file. The sampling time must be setted from 1ms to 10s with a maximum jitter of 60µs. The piston stroke is 200mm, its maximum speed is 500mm/s and its maximum acceleration is 8m/s2.
The following scheme shows the general architecture of the plant used for the test bench automation.
The controller is realised by a standard PC (a 1200MHz Celeron II with 128 Mbyte DRAM) where a CAN interface card (Eurotech COM1270) and an analog inputs card (Measurement Computing PCI-DAS1200/jr) with sixteen 12-bit channels and 24 TTL DIO are plugged in.
The brushless motor control (Parker SBC sLVD) is exclusivelly performed using the CAN fieldbus by which, at 1000Hz frequency, the speed and position references are given and the piston actual position and the driver status are read.
Via ethernet the controller is linked to the firm LAN. It provides SAMBA and FTP services by which it is possible to remotely update the file of the graph to be executed on the test bench and the file with the samples performed during the test.
Input space-time graph to be executed (yellow dots) and sampled movement really executed by piston (green line).