exploratory testing of washing machine using hardware … · exploratory testing of washing machine...

1 Confidential | ETAS | Whirlpool | 2014-04-14| All rights reserved, also regarding any disposal, exploitation, reproduction, editing,

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

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

Akshay P Chouhan

GTEC, Whirlpool

Myrtle Binil R

ETAS Automotive India Private Limited



Agenda

Introduction

Washing Machine Validation- Challenges

Hardware in Loop Testing for Washing Machine

Plant Model – For closed loop testing

Advantages

Summary



Requirement Specification

Introduction

– Product Life Cycle

Design & Coding

Validation

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



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

Simple rotary type controlAdvanced touch interface control

Early ’90s Later 2000’s



– 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

Washing Machine Validation – Challenges



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.



IO Cards

Real Time Controller

Hardware in Loop Testing for Washing Machine

Control Unit

Signal Conditioning

Actuators

Acquisition Generation

Simulink Plant Model

Other Process

Design

SensorsReal Loads

User Interface PanelWIDE

AC mains

The main control unit of washing machine

User interface panel, where all user controls are presents

(Like knobs, touch screen controls)

WIDE protocolProprietary to whirlpool

IO Card Modules

Signal conditioning unit for AC to DC isolation

Real time controller



Real Time PC

Hardware in Loop Testing for Washing MachineDesign Realization

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

Control Unit

Signal Conditioning Unit

ES5340 Multi-IO Cards

Host PC

Break out BoxWIDE

IP EE

– In Mini-LABCAR, PCIe based

Multi-IO card ES5340

Master and Slave are used

to simulate and acquire

different signals of control

unit.

– Signal Conditioning unit

acts as a isolation between

AC and DC signals and

signal conversion

– In LCO-EE, interface is

developed to communicate

with the WIDE interface



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.

Parameter-Washing Machine -Environmental

Washing machine functionalityMath model of washing machine components

Interface to LABCAR components




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




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

Washer Plant Model

Different Sensor Models

– With this a structured way of development and integration was possible

– The actuator models were also integrated into the system, on need



ETAS Real Time PC


The complete flow of system

Control Unit

Plant Model

Sensor Models

LABCAR IO ES 5340

LABCAR IO ES 5340

Actuator models

Physical QuantityElectrical Value

Electrical Value

Physical Quantity

Signal Conditioning

Host PC

WIDECommunication



Advantages

– 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

Testing of different conditions are now simple with click of buttons

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



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



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.



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…



Thank You

Q&A

exploratory testing of washing machine using hardware … · exploratory testing of washing machine...

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