| The photograph shows the
actuator (on the right side) with a dual sensor for
torque and position (on the left side). The actuator
consists of an rotary magnet (limited angle torquer LAT,
actuation angle: +/- 70°, by stops limited to +/- 62°). The
angular position of the magnet is sensed by an integral
potentiometer. The actuator is always acting against a
spring pre-load, so in the case of loss of electric
power the spring will shut down the engine safely.
By the magnitude of the
motor current, acting in the actuator, the actuator can
position against the spring pre-tension. The integral
potentiometer closes the control loop. The actuator is
connected by a MIL connector (shown in front of the test
stand) to the supervising system.
The actuator is almost
permanently acting (against the spring). So care must be
taken with the self-heating, especially because the
actuator is mounted directly on the hot engine block. So
we made extensive tests to verify the thermal behaviour (parameter
identification, simulations of various scenarios).
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