A machine that operates displays like a thumb. A drivetrain test bench that shifts gears while it measures. A series test bench that only became what it was meant to be with its own software and stronger motors. These three were built in a previous role as development engineer, two of them stand in the ENGtron test field today. The fourth is developed in-house by ENGtron: a brake test bench that pushes the lever like a hand.
Click-and-swipe test bench in operation: the stylus moves to the control points on the display.
01
Special machine engineering
Click-and-swipe test bench built from a converted CNC mill
Realised in a previous role as development engineer
A display cannot be simulated away, it wants to be operated. So an existing CNC gantry mill became a machine for automated touchscreen testing: a stylus on the Z axis taps or swipes on the clamped test object, always at the same spot, always with the same force.
Conversion instead of new build: gantry kinematics, drives and guides were already there. New are the tool holder, the control and the test sequence.
Two operating modes: click for single taps, swipe for swipe gestures. Three axes reach every point of the user interface.
The actuation force is adjustable. Every test object is operated with the force that suits it, not with whatever force the machine happens to apply.
The test object is clamped on the slotted table and keeps its position throughout the entire test run.
What never comes out the same twice by hand runs here for hours without supervision.
Special machine engineering
Display and HMI testing
Touchscreen test automation
Endurance runs
Drivetrain test bench: the derailleur changes sprocket while torque and speed are recorded.
02
In-house test bench
Drivetrain test bench: shifting while measuring
Built in a previous role, taken over from that employer, in operation in the ENGtron test field in Reutlingen today
Drive motor and load motor clamp the test object between them, with two DAkkS-calibrated torque sensors in front of and behind it. That makes visible what a shift under load really costs: torque drop, feedback into the drive, behaviour over long endurance runs.
2× HBM T210 (200 Nm), DAkkS-calibrated, 0.1 %, on the drive and output side.
Linux Real-Time with EtherCAT and 1 ms cycle time. Control and evaluation are our own development.
Speed, torque, power and position control, including a realistic pedal torque profile per crank revolution.
Safety concept with a Pilz PNOZmulti safety PLC, designed for automated endurance runs.
The retrofitted eChecker in operation: pedelec on the roller, hub with brake disc and servo drive, readings on the test bench computer.
03
Retrofit and modernisation
Retrofit eChecker: a series machine became our roller test bench
Rebuilt in a previous role, taken over from that employer, in operation in the ENGtron test field in Reutlingen today
The eChecker was available to buy. What it could do ex works was not enough for the measurement tasks ahead. Instead of replacing it, it received stronger test bench motors and its own safety concept, and the supplied software was thrown out.
More powerful test bench motors in place of the series drives, so the bench covers load cases the series machine was not designed for.
The test bench software running on it today was written after that role: developed from scratch by ENGtron, with an operator interface for control and test automation and its own real-time software including the controllers. Licence-free, and new features arrive when the test bench needs them, not when a licensor schedules them.
Its own safety concept with a CE target picture, developed for the rebuilt bench rather than inherited from the series machine.
Retrofit instead of new purchase: the bench stayed, its limits disappeared.
Static brake characterisation of a SRAM Maven: test bench software on the left, test bench on the right, the three characteristic curves at the end.
04
In-house development
Brake test bench: "feels better" becomes numbers
Developed and built by ENGtron: mechanics, electrics and test bench software
Everyone describes the feel of a brake lever differently. Nobody sees what reaches the pads. Here a spindle pushes the lever like a hand, two force sensors measure lever force and clamp force, and the test bench software records both in sync with the lever travel.
Lever force from a force sensor on a pendulum link, lever angle compensated. Accuracy ±2 N.
Clamp force from a force sensor between one piston pair, the opposite pair is blocked.
Three ramps at 3 mm/s, automated test case and automated evaluation. Every brake runs through the same sequence.
Result per brake: clamp stiffness, force ratio and hysteresis. For the SRAM Maven in the video 155 N/mm and 45 : 1, so it compares directly with other brakes.
Brake test bench
Brake characterisation
Test bench software
Test automation
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