EMPLOYING REAL-TIME LINUX IN A TEST BENCH FOR ROTATING MICRO MECHANICAL DEVICES

Abstract

This paper describes a testing stage based on RTLinux for characterising rotating micro mechanical devices in terms of their performance, quality and power consumption. In order to accomplish this, a kernel module employs several real time threads. One thread is used to control the speed of a master rotating up to 40000rpm by means of an incremental coder and a PCI counter board with the corresponding interrupt service routine. Another thread controls the slave motor to be tested, synchronised to the coder impulses using voltage functions saved in shared memory. The measurement thread is then responsible to acquire date synchronously to the rotor angle and stuffs data on voltages, currents, torque and speed into different FIFOs. Finally, a watchdog thread supervises timing and wakes up a users space program if data have been put in the FIFOs. This GTK+ based graphical users space application prepares control information like voltage functions, processes data picked up from the FIFOs and displays results in figures.

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Copyleft 1999, Peter Wurmsdobler.