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Test generation from functional 3D
virtual environment models
Barath Kumar1, Rainer Drath2 and Juergen Jasperneite3
(Contact: [email protected])
1 inIT – Institute of Industrial Information Technologies, Germany (former employer).
1 dSPACE GmbH, Paderborn, Germany (current employer).
2 ABB Corporate Research Center, Ladenburg, Germany.
3 Fraunhofer IOSB – INA, Anwendungszentrum Industrial Automation, Lemgo, Germany.
2 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Objective of the prototype
Automated test case generation from 3D virtual production floor models (plant models) for Programmable logic Controller (PLC) testing.
3 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
To Test
Control software of:
Migrating PLCs (i.e. PLCs with updated logic)
Exchanged PLCs (i.e. New hardware without changes to logic)
4 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Errors to be identified in the control logic:
• Logical Errors
• e.g. If the tray is empty, does the PLC take an appropriate action?
• Timing Errors (Not considered in this work)
• e.g. If the tray is empty, does the PLC take appropriate action in a pre-defined duration?
• Plant Errors
• e.g. if a sensor is broken can the PLC still handle the plant appropriately
5 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Haves and Challenge
• A 3D virtual representation of a production facility (plant model). This virtual facility can mimic the workings of the real plant – when we provide the necessary stimulus
• We know how to generated test cases from formal behavior models
• To extract the necessary behavior information from the 3D virtual plant model to construct formal behavioral model of the plant
Our Challenge:
Haves:
6 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Proposed Approach
Plant Model (Robot Studio Model)
Formal Model
of the Plant
Behavior
(Test Model)
Learning
Test Case
Generation
Test Suite
Test Case
Execution
PLC
7 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Proposed Approach
Plant Model (Robot Studio Model)
Formal Model
of the Plant
Behavior
(Test Model)
Learning
Test Case
Generation
Test Suite
Test Case
Execution
PLC
8 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Hardware-in-the-loop (HIL) Simulation - Information Source
Plant Model
Reference PLC
Industrial
Bus
Hardware-in-the-Loop Model Learning Setup
9 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Model Learning
Learning
Signal Analyser
Plant Model (Robot Studio Model)
Formal Model
of the Plant
Behavior
(Test Model)
10 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Virtual Plant Model
Sensor 3
Sensor 2
Sensor 12
Sensor 4
Sensor 11
11 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Information from Signal Analysis
Sensors (State Variables)
12 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Information from Signal Analysis
State Variables
and so on..
Event Occurrence
e.g. State Structure: 0 0 0 0 0
s2
s3
s12
s4
s1100000 00010
00011
13 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Formal Plant Model (Test Model)
00000
0001000011
e.g. Structure: 0 0 0 0 0
s2
s3 s4
s11s12
14 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Plant Model (Robot Studio Model)
Formal Model
of the Plant
Behavior
(Test Model)
Learning
Test Case
Generation
Test Suite
Test Case
Execution
PLC
Test Case Generation
15 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Test Case Generation (with coverage criterion)
Test case
generationCoverage
criterion
Q
Test case
is the
Coverage criterion
met?
No
Yes
1
3
2
4
5
a
b
c
def
g
h
Test model/Automaton Final_test_suite
{
// All paths from state 1 to
state 5
a ; b ; h ;
a ; b ; e ; f ;
a ; d ; f ;
}
Test suite
16 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Generated Test Suite
Module Test Suite
s3 = 1;s2 = 1;s3 = 0;s12 = 1;s2 = 0;s12 = 0;
s3 = 1;s2 = 1;s3 = 0;s2 = 0;
s3 = 1;s3 = 0;
s2 = 1;s12 = 1;s2 = 0;s12 = 0;
s2 = 1;s3 = 1;s3 = 0;s12 = 1;s2 = 0;s12 = 0;
s2 = 1;s3 = 1;s3 = 0;s2 = 0;
s2 = 1;s2 = 0;
s11 = 1;s11 = 0;
s11 = 1;s4 = 1;s4 = 0;s11 = 0;
s11 = 1;s4 = 1;s11 = 0;s11 = 1;s4 = 0;s11 = 0;
s11 = 1;s4 = 1;s11 = 0;s4 = 0;
s4 = 1;s11 = 1;s4 = 0;s11 = 0;
s4 = 1;s11 = 1;s4 = 0;s4 = 1;s11 = 0;s4 = 0;
s4 = 1;s11 = 1;s11 = 0;s4 = 0;
s4 = 1;s4 = 0;
Test case generation time: 00:00:45.5781250 seconds
Avoided loops : 8
Generated test cases: 15
17 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Plant Model (Robot Studio Model)
Formal Model
of the Plant
Behavior
(Test Model)
Learning
Test Case
Generation
Test Suite
Test Case
Execution
PLC
Test Case Execution
Completes the process
but not part of this
pilot project
18 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Analysis of the Approach
• Errors in ‘Migrating PLCs’ and on ‘Exchanged PLCs’ can be detected
• No manual formal modeling effort is required
• This approach can be adopted even for testing legacy systems thathave been in existence for decades
• Existence of a reference implementation (‘Reference PLC’) is a pre-requisite
• As the reference implementation is the input for the learned model,logical errors present in the reference implementation cannot bedetected
19 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Outlook
• Learning of continous behavior
• Learning of non-deterministic behavior
• Learning of real-time behavior
• Test case generation from complex ‘non-deterministic hybrid real-time’ models
• Identification of timing errors
20 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
I am done !
21 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Reserve Slides
22 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Information from Signal Analysis
State Variables
and so on..
Event Occurrence
e.g. State Structure: 0 0 0 0 0
s2
s3
s12
s4
s1100000 00010
00011
23 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Formal Plant Model (Test Model)
00000
0001000011
00001
01000
10000 11000
10100
00100
e.g. Structure: 0 0 0 0 0
s2
s3 s4
s11s12
24 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Benefits
• Cost-effective
• Reduces plant down-time (planned and unplanned downtime)
• Surprises during commissioning can be minimized
• To improve testing thoroughness and maintenance of tests cases
25 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Analysis Summary
Logical Errors Plant Errors
Reference PLC No Yes
Exchanged PLC Yes Yes
Migrating PLC Yes Yes
26 | 17.09.2014 | Barath Kumar – Test generation from functional 3D virtual environment models
Test Case Generation (Basic Idea)
1
3
2
4
5
a
b
c
def
g
hTest case
generation
Test Model / Automaton
Test_case
{
a ; b ; h ; g
}