Exploratory testing of Washing Machine using Hardware-in-Loop Testing

Exploratory testing of Washing Machine using Hardware-in-Loop Testing
Exploratory testing of Washing Machine
           using Hardware-in-Loop Testing



                                                                                                          Akshay P Chouhan
                                                                                                          GTEC, Whirlpool

                                                                                                          Myrtle Binil R
                                                                                                          ETAS Automotive India Private Limited




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Exploratory testing of Washing Machine using Hardware-in-Loop Testing
Agenda




       Introduction

       Washing Machine Validation- Challenges

       Hardware in Loop Testing for Washing Machine

       Plant Model – For closed loop testing

       Advantages

       Summary




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Exploratory testing of Washing Machine using Hardware-in-Loop Testing
Introduction


 – Product Life Cycle


                 Requirement                         Design &
                                                                                          Validation
                 Specification                       Coding
                                                                                                                                            SOP



 – Validation refers to set of tasks that ensures the component is build as per
   the specification.
 – In Whirlpool,
    – These validations are done manually
    – Validation are done with real prototypes




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Exploratory testing of Washing Machine using Hardware-in-Loop Testing
Washing Machine Validation – Challenges



 – Difficulty to test different sequence of test case in the real prototype.

 – Difficulty to generate different test conditions such as
         – Eg: Testing over flow error
                    – For this user have to tweak the sensor signal in precise manner

                    – Wait until the overflow occurs in the machine (This also requires to disconnect the
                         feedback signals to the controller which will lead to some other diagnostic errors)

 – More features into washer, complex functionality
                                                                                                                Advanced touch interface control
           Simple rotary type control




                      Early ’90s                                                                                                            Later 2000’s

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Washing Machine Validation – Challenges



 – Standards and safety features in the washer make the software complex
       and therefore thorough validation w.r.t these should be done to get the
       product certified.

 – More intelligence in the product increase the complexity of diagnostics
       routines which is time consuming to test manually

 – Expensive prototypes for testing

 – Time to market
         –       On-Time delivery of product

         –       Quality of product




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     distribution, as well as in the event of applications for industrial property rights.
Washing Machine Validation – Overcoming the challenges



 – To overcome these challenges in validation, hardware in the loop testing
       concept which is widely used in automotive industry was explored.

 – With the help of ETAS, the possibilities are studied and this brought
       sufficient improvement in testing w.r.t quality of testing and time.

 – ETAS DESK-LABCAR system with efficient signal conditioning unit was used
       for testing the washer.

 – ETAS LABCAR automation software was used to automate the test cases for
       washer.

 – ETAS Variant Management system was used to manage different variants of
       washer of same hardware platform.




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Hardware in Loop Testing for Washing Machine
Design

                                                                                                                                     WIDE protocol
 The main control unit of                                                                                                        Proprietary to whirlpool
    washing machine
                                                                                   AC mains

                                                                                                                      User Interface
                                                    Control Unit
                                                                                                 WIDE                     Panel
                                  Actuators                                    Sensors
 Real Loads                                                                                                                                   User interface panel, where all user
                                                                                                                                                     controls are presents
                                                                                                                                              (Like knobs, touch screen controls)
                                             Signal Conditioning
                                                                                                         Signal conditioning unit for AC to DC
                                                                                                                        isolation


                                       Acquisition                     Generation
     IO Card
     Modules                                            IO Cards


                                       Simulink Plant
                                                                    Other Process
                                          Model

                                         Real Time Controller
                                                                                                                Real time controller




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Hardware in Loop Testing for Washing Machine
Design Realization

 ETAS DESK-LABCAR system as shown below is used to realize the design

                                                                                                                                –       In Mini-LABCAR, PCIe based
                          Control Unit                                                                                                  Multi-IO card ES5340
                                                                                                                                        Master and Slave are used
                                                                                                                                        to simulate and acquire
             Signal Conditioning Unit                                                                                                   different signals of control
                                                                                                                                        unit.

                                                                                                       WIDE
                                                                                                                                –       Signal Conditioning unit
                        Break out Box                                                                                                   acts as a isolation between
                                                                                                                                        AC and DC signals and
                                                                                                                                        signal conversion
                ES5340 Multi-IO Cards                                                         IP                 EE
                                                                                                                                –       In LCO-EE, interface is
                                                                                                 Host PC                                developed to communicate
                        Real Time PC                                                                                                    with the WIDE interface



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Plant Model – For Closed Loop Testing


  –     To cover most of the test cases during validation, a closed loop setup is required.
  –     This is achieved by developing a plant model of washer in MATLAB®/Simulink and
        integrating this to LABCAR
  –     With the different features of Simulink modeling, a structured mathematical model of
        washing machine was developed in short duration.




                                                                                                                                    Washing machine functionality
                                                                                                                                    Math model of washing machine
                                                                                                                                    components

Parameter
-Washing Machine
-Environmental


                                                                                                                                  Interface to LABCAR components




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Plant Model – For Closed Loop Testing


                                                                                                                               Water Inlet :
                                                                                                                               Functionalities of inlet pipe for hot
                                                                                                                               water, cold water, steam fill etc.



                                                                                                                               Temperature Control :
                                                                                                                               Maintaining the temperature based on
                                                                                                                               heater status, water temperature



                                                                                                                                 Drum Model :
                                                                                                                                 All functionalities related to drum
                                                                                                                                 such as cloth soaking, agitation etc..



                                                                                                                                 Drain Control :
                                                                                                                                 All functionalities related to draining
                                                                                                                                 of water from the washer.


                                                                                                                                 Switches:
                                                                                                                                 Simulation of all kind of switches
                                                                                                                                 related to washer, such as lid lock, lid
                                                                                                                                 close etc...

                                                                                                                                 Detergent Dispense:
                                                                                                                                 The detergent dispense module
                                                                                                                                 model, containing all the functionality
                                                                                                                                 to dispense the detergent


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Plant Model – For Closed Loop Testing

      In the same manner, all the sensors are also modeled and integrated in the LCO-IP




                                                                    Different Sensor Models




                                                                Washer Plant Model




 – With this a structured way of development and integration was possible
 – The actuator models were also integrated into the system, on need




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Plant Model – For Closed Loop Testing

The complete flow of system


                                                                           Electrical
      Physical Quantity
                                               Sensor                      Value                   LABCAR IO
                                               Models                                                  ES 5340


                                                                                                                                               Signal        Control
  Plant Model                                                                                                                                Conditioning     Unit

                                                                             Electrical
                                                                             Value
                                              Actuator                                             LABCAR IO
      Physical Quantity                       models                                                   ES 5340


                                        ETAS Real Time PC

                                                                                                                                             WIDE
                                                                                                                                             Communication
                                                   Host PC


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      distribution, as well as in the event of applications for industrial property rights.
Advantages

Testing of different conditions are now simple with click of buttons
 –       Example: Overflow Error check
           –      Stuck conditions on inlet value will continuously fill water into the drum. This creates the
                  over flow error, which can be validated very easily and in precise manner

                                                                                    Inlet stuck
                                                                                    subsystem


                                                                                                Simulation of stuck with
                                                                                                LCO -EE




 –       Example: Invalid Pressure
           –      Providing an invalid pressure to the system and verifying the behavior is also simple by click
                  of button, by overriding the actual values from plant
                                                                                               Overriding
                                                                                               pressure
                                                                                               value




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Advantages


 –       More over different types of simulation such as leakage in the drum, over
         temperature error validation, different fill error validation can be simulated in the
         system in very simple steps and verified in précised manner.




                                                                                                                                            Different control in
                                                                                                                                            EE for simulation of
                                                                                                                                            different test
                                                                                                                                            conditions




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Advantages


 –       Automation of Test Case
           –      With the closed loop setup, full automation of test cases which runs for hours are easily executed
                  and the test results are studied. Test reports are generated which also ensure that documentations
                  are in place.




 – Integration with Variant Management System
         –      LCO integrated with ETAS variant management system also ensures that the generic plant
                model can be used across different variants only by changing the sensor parameters.
         –      Changing the generic model parameters such as drum volume, pipe diameters will ensure
                that the plant model is ready for the next variant.


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Summary


–      Having an closed loop HiL system with detailed plant model built in Simulink ease the
       validation and improve efficiency.

–      With the help of automation, it was able to repeat different test cases at any point of
       time with the same artifacts.

–      Tweaking of sensor values are now no more an difficulty, as they are now done just
       with change values and click of buttons.

–      The HiL validation was extended to different products such as
         –      Dish washer

         –      Refrigerator

         –      Food Processor etc…




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Thank You
                                                                           Q&A




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