Developed by an independent electronics design company for a single project, a test rig for putting the next generation of controls for medium altitude long endurance (MALE) drones through their paces employs a precision TorqSense sensor from Sensor Technology. The sensor performs the critical task of collecting data from the rig for analysis. Its wireless operation allegedly makes it quick and easy to install, yet it is capable of generating vast amounts of accurate data.
MALE drones or unmanned aerial vehicles (UAVs) typically fly at 10,000ft to 30,000ft for 24 to 48 hours. Obviously, due to the duration of flight, their controls must be reliable and accurate.
Essentially, the TorqSense transducer constantly measures the power output at the motor shaft and this is compared to the instantaneous current draw. By taking a large number of individual readings over the duration of the test period an accurate torque-load curve can be plotted for each motor and compared with the expected values.
TorqSense does not need to physically contact the shaft it is monitoring. Sensing is achieved through a radio frequency link. Two piezoelectric combs are attached to the shaft of the motor under test, perpendicular to one another and at 45° to the axis of the shaft. These form half of a Wheatstone bridge circuit, which is in radio contact with the other half in the main body of the TorqSense.
Significantly, because TorqSense is essentially wireless it is easy to set up, there being no cables there is no need for delicate and fiddly slip rings. This means test rigs can be both set up and operated easily. TorqSense is available from Sensor Technology Ltd., Oxfordshire, UK. +44 (0)1869 238400 and/or [email protected]