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Test Rigs - Case Studies

Crash Test Rig

Our client (TRL Ltd) operates a range of transport research and test facilities.  A new facility has been built for testing components such as child seats, wheel chair securing attachments, F1 racing car nose cones, etc.  JK Controls Ltd. have designed, built and commissioned the controls for operating the test and recording results.

A trolley carries the sample under test, which is projected along a track by strong rubber cords using a patented design.  The trolley is then brought to rest by means of a rapid deceleration apparatus or by impact with a solid steel wall, dependent upon the type of test being carried out.

JK Controls supplied a PLC and SCADA based control system to handle the test set-up, test sequencing, safety interlocking, data gathering and post-test recording of results.  The system uses Microsoft Access for data set-up and results history, Citect SCADA for operator interaction, and Mitsubishi Q series PLC for data I/O and control.  The screen appearances of the software systems are customised to give a consistent ‘house’ look.

The operator is able to type in a desired impact speed, the number of cords and the diameter of the cords, as well as many other menu based test set-up characteristics.  The trolley is weighed and the point of initial impact registered.  The trolley is winched back and the system then carries out a calibration sequence using force and position measurements with calculations to determine the desired release point for the trolley that will enable the final speed at impact to be within 1% of the desired value.  At the onset of impact a high speed measuring phase is started which gathers depth of impact data, checks its validity, stores the data and records the greatest depth of impact prior to rebound.  Position measurement was a challenge due to the rapid movement, deceleration and non-contact requirement of the application.  We researched several methods of measurement and carried out extensive tests, finally settling upon a Sick-Stegmann laser system with rapid update.  This enables measurement of impact depth to within 2mm and location of the trolley over the full track length of 22 meters.

On completion of the test further data is recorded regarding maximum acceleration prior to impact and measured impact speed.  The stored energy at release and the energy actually imparted at impact are calculated to determine the efficiency and hence refine the calibration of subsequent tests.

JK Controls built the control panels and custom designed electronic systems for speed measurement and calibration.

Crash Test Rig Control Cabinet SCADA Screen

 

Aircraft Wing Brake Test Rig

JK Controls have designed, developed and built bespoke instrumentation and controls for a test stand for a prototype aerolon brake.

The aerolon drive shaft is held by an electrically operated brake when not required to rotate.  The brake has to bring the shaft to a halt within 40mS of being de-energised.  For testing purposes the shaft is rotated by a motor at up to 1500 rpm.  The motor is driven by a variable speed inverter at a preset speed.  On de-energising the motor, the shaft free-wheels for a few msecs and the speed is measured.  The brake is then de-energised and the shaft monitored until it ceases to rotate.  Timers automatically start and stop during the braking event.

This project required several custom designed components where there were no suitable proprietary products available.  As the shaft stops within 40 msec. it only turns about one quarter of a  turn from running to stopped.  Therefore the speed was measured using a very fine resolution printed slotted wheel and a suitable optical detector.  Physical constraints prevented access to either end of the shaft, the slotted disk was therefore custom made, together with the high speed optical detector by JK Controls Ltd.  Using fast hardware processing the shaft was determined as stopped when the pulse repetition rate dropped below a threshold.  The timing and measurement logic was designed and built on to custom printed circuits.  During the braking period the brake torque is measured by a strain gauge and the peak braking torque, in both directions, is stored.  Analogue hardwired circuits were built to sample-hold for peak torque and initial speed stores.  The stored values are displayed on suitably scaled digital indicators.

The sequence of running up the motor, priming the data collection and timers, initiating the test and monitoring the results was handled by a small PLC.  Various safety interlocks are built in to prevent operation under unsafe conditions.  Great care was taken to minimise sensitivity to, and radiation of, electro-magnetic interference.


Brake Test Rig
Bespoke Instrumentation
Occulting Disk
Custom built control panels
Control Panel
Bespoke printed circuit boards
Peak Torque Detector
Custom built instrumentation
Optical Detector

Alarm System PCB Test Rig

Computer controlled test rig for automatic testing and validation of production alarm system PCBs.

 

Contact Information: e-mail to info@jkcontrols.co.uk, or telephone +44 1732 522353  

Registered Address: JK Controls Ltd, The Barn, 65 High Street, East Malling, Kent, ME19 6AJ.  Reg. No. 3073964

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