The EPB functional test rig is integrated into a mobile 19" cabinet. At working height, on one side a holding device is mounted for the EPB drive with motor and gear, and on the opposite side a holder for the brake is installed. The drive is connected to the brake via a torque measuring shaft. Thus torque is measured as well as speed and angle of rotation over a built-in incremental encoder. A load cell inserted in the brake is used to measure the clamping force. The motor is operated in 2 directions of rotation. The actuation voltage can be freely selected between manual and automatic mode. Voltage and current are also measured. The input power is calculated from voltage and current, the output is calculated from torque and speed. The efficiency of the drive is calculated from input and output. Taking into account spindle pitch, the efficiency of the spindle is calculated from the torque and the actual clamping force. Actuation of the device under test (DUT) is controlled by a µC on an external board that is located in the GdS-control module. Data exchange between PC and GdS-control module takes place over serial communication (RS232). 

An actuation cycle consists of two phases: 

ON-time during which the brake is closed or actuated until reaching the switch-off criterion (switch-off current or switch-off clamping force) 

OFF-time during which the brake is released until reaching the release current, including follow-up time. 

The operating software "EPBPerformance.exe" performs following tasks: 

• Control of the operating voltage, current limit and the hydraulic pressure over D/A outputs of the National Instruments PCI 6229 controller card. 

• Control of the drive, clamping and release via the GdS-control module. 

• Switch-off in case of definable current or external signal (clamp force). 

• Calculation of the angle of rotation by increment of the incremental encoder signals including 

• Calculation of speed by edge distance measurement, including direction of rotation. 

• Calculation of all performance levels and efficiencies (drive, spindle), see section 1.3. 

• Visualization of data in different graphs in the plotter. 

• y/t graphs with all measurement channels and calculated sizes, channels can be faded out. 

• x/y graphs, all channels can be selected as x-axis, y-scales can be faded out. 

• Storage of all measured values and calculated values including a header that comprises specific data of the DUT, inspection time and tester, in a Lucas data file ("*.LDFII"). 

Hardware 

phases: 

• Schroff 19" cabinet, worktop at about 1050 mm with holder for DUT. 

• Cradle for quick changing of the DUTs. 

• Monitor, keyboard and pull-out mouse pad recessed in drawer. 

• PC, 2.8 GHz, with National Instruments PCI 6229 M-Series measurement and control card and CAN card. 

• TRW signal conditioning max. 18 channels, 3xDMS, 3xISO, 3xTemp 

• Power supply, 40 Volts (or 20 Volts), 70 Amps. 

• 200 bar pressure transducer with prop. valve and pressure sensor 

• GdS-control module comprising control with Hall signal conditioning and actuator temperature measurement.

1—Cable harness for EPB actuator (motor). 

2—EPB actuator, motor and gear (DUT). 

3—Socket to connect the actuator (electrical). 

4—Brake line for connecting the DUT (hydraulic). 

5—Plug to connect the torque sensor. 

6—Measuring shaft for torque, speed and angle of rotation. 

7—Load cell (clamp force measurement). 

8—EPB brake (DUT). 

9—Port for the EPB brake (hydraulic). 

10—Holder for the EPB brake with motor and gear.

1—Drawer for keyboard and mouse. 

2—Industrial PC with operating system Microsoft Windows XP Professional. 

3—TRW signal conditioning. 

4—BNC - outputs for all analogue measurement channels. 

5—Power supply unit for all test components (sensors, proportional valves ...). 

6—BNC connection cable of analogue measurement channel for clamping force with the external signal input of the GdS-control module (for switch-off over clamp force).  

7—Power supply, 40 Volts (or 20 Volts), 70 A, for supply of the EPB actuator.