HIL Simulation Lab Work

Transcription

1 HIL Simulation Lab Work with Step by Step Exercises that you can do in your own Pace Hans-Petter Halvorsen

2 Introduction to HIL Lab Work Hans-Petter Halvorsen

3 Lab Assignment Overview 1. Control and Simulation in LabVIEW using built-in PID Controller (Software only) Create (or use prebuilt), Simulate and Control a Mathematical model of an Air Heater (Software only) 2. HIL Simulation using PXG5 PID (HW + SW) Control Mathematical model using PXG5 Test Auto-tuning with PXG5 PID 3. Test PXG5 on Real Process (Hardware only) See next slides for details...

4 HIL Simulation Lab - Step-by-step 1 Step 1: Ordinary Software Simulation: Purpose: Create, Simulate, Control and Test the Mathematical Model 2 Step 2: HIL Simulation: Purpose: Test your Hardware device before you apply it on your real system. Also useful for Training purposes. Mathematical Model Mathematical Model 3 Step 3: Running the Real System: Purpose: Apply your Hardware in the Production System

5 Lab Overview Step 1: Simulation Control and Simulation in LabVIEW using built-in PID Controller and Mathematical Model of the process (Software only) Computer (with LabVIEW)

6 Lab Overview Step 2: Use PXG5 with Model PXG5 Industrial PID Controller Analog Out (Process Value) 1-5V AO0 GND Note!! USB Model of Process (Air Heater) Mathematical Model PID Controller AI0+ AI0- Analog In (Control Signal) 0-5V I/O Module (USB-6008) Computer (with LabVIEW)

7 Lab Overview Step 3: Use PXG5 with Real System PXG5 PID Controller Process (Air Heater) + Process Value - 1-5V + Industrial PID Controller - Control Signal 0-5V

8 Necessary Software Software LabVIEW LabVIEW Control & Simulation Module DAQmx Driver Software Make sure to install the necessary Software before you go to the laboratory!

9 Hardware Hardware USB-6008 Air Heater Fuji PXG5/PXR5 PID Controller Multimeter Your Personal Computer We have limited numbers of PID Controllers, so 2 students may need to share a PID Controller

10 The teacher have not done all the Tasks in detail, so he may not have all the answers! That's how it is in real life also! Very often it works on one computer but not on another. You may have other versions of the software, you may have installed it in the wrong order, etc... In these cases Google is your best friend! The Teacher dont have all the answers (very few actually L)!! Sometimes you just need to Google in order to solve your problems, Collaborate with other Students, etc. Thats how you Learn!

11 You probably will find the answer on the Internet Troubleshooting & Debugging Visual Studio Use the Debugging Tools in your Programming IDE. Visual Studio, LabVIEW, etc. have great Debugging Tools! Use them!! Google It! My System is not Working?? Your hardware device most likely works, so you don't need a new device! Still not working after Troubleshooting & Debugging? Fill out an Equipment Error Form Use available Resources such as User Guides, Datasheets, Text Books, Tutorials, Examples, Tips & Tricks, etc. Another person in the world probably had a similar problem Check your electric circuit, electrical cables, DAQ device, etc. Check if the wires from/to the DAQ device is correct. Are you using the same I/O Channel in your Software as the wiring suggest? etc.

12 Lab Assignment Guidelines Make sure to read the whole assignment before you start to solve any of the problems. If you miss assumptions for solving some of the problems, you may define proper assumptions yourself. The Tasks described in the Assignment are somewhat loosely defined and more like guidelines, so feel free to interpret the Tasks in your own way with a personalized touch. Feel free to Explore! Add Value and Creativity to your Applications! Try to add some extra value and be creative compared to the simplified examples given by me, in that way you learn so much more.

13 Introduction to HIL Hans-Petter Halvorsen

14 The main purpose with the HIL Simulation is to test the hardware device on a simulator before we implement it on the real process. What is HIL Simulation? Hardware-in-the-loop (HIL) simulation is a technique that is used in the development and test of complex process systems. HIL simulation provides an effective platform by adding the complexity of the plant under control to the test platform. The complexity of the plant under control is included in test and development by adding a mathematical representation of all related dynamic systems. These mathematical representations are referred to as the plant simulation. Hardware-In-the-Loop is a form of real-time simulation. Hardware-In-the-Loop differs from realtime simulation by the addition of a real component in the loop. This component may be an Electronic Control Unit (ECU). [Wikipedia]

15 Example of PC-based Control System (We shall not do like this in this Assignment!) Process (Air Heater) Computer (with LabVIEW) USB Analog In (Process Value) AI0+ 1-5V AI0- AO0 GND I/O Module (USB-6008) 0-5V Analog Out (Control Signal) PID Control and Monitoring

16 Example of HIL Simulation Analog Out (Process Value) 1-5V AO0 USB Model of Process (Air Heater) GND Note!! Mathematical Model PID Control AI0+ AI0- Analog In (Control Signal) 0-5V I/O Module (USB-6008) Computer (with LabVIEW)

17 Example of Industrial Single Loop PID Control (This is our final goal in this Assignment) + - Process Value 1-5V Process (Air Heater) + Industrial PID Controller - Control Signal 0-5V

18 Examples of Industrial Control Systems (ICS) Industrial Control Systems are computer controlled systems that monitor and control industrial processes that exist in the physical world National Instruments crio LabVIEW Programmable Automation Controller (PAC) Industrial PID Controller Distributed Control Systems (DCS) Controller PC based Control System/SCADA System (Supervisory Control And Data Acquisition) I/O Module PLC (Programmable Logic Controller) I/O Modules DeltaV from Emerson Siemens PLC

19 HIL Lab - Background Theory Typically, a simulator communicates with an ECU ( Electronic Control Unit ) via ordinary I/O. Such a system - where the real controller is controlling a simulated process is denoted Hardware-in-the-loop (HIL) simulation. The main purpose of this lab is to test the hardware device on a simulator before we implement it on the real process. If the mathematical model used in the simulator is an accurate representation of the real process, you may even tune the controller parameters (e.g. the PID parameters) using the simulator. We will test the Fuji PGX5 PID controller on a model, and if everything is OK we will implement the controller on the real system.

20 Traditional Process Control using Software for Implementing the Control System PID Software u Process Hardware y y u AI AO DAQ Theory HIL Simulation PID Hardware u Software y Process Mathematical Model u y AI AO DAQ

21 HIL Simulation Theory Hardware-in-the-loop (HIL) simulation is a technique that is used in the development and test of complex process systems The HIL simulation includes a mathematical model of the process and a hardware device/ecu you want to test, e.g. an industrial PID controller we will use in our example. The hardware device is normally an embedded system The main purpose with the HIL Simulation is to test the hardware device on a simulator before we implement it on the real process It is also very useful for training purposes, i.e., the process operator may learn how the system works and operate by using the hardware-in-the-loop simulation Another benefit of Hardware-In-the-Loop is that testing can be done without damaging equipment or endangering lives.

22 HIL Simulation using PXG5 PID Controller PXG5 PID Controller Control Signal u Scaling? It depends on your settings u [0 5V] u [0 5V] USB-6008 Analog In (AI0) Simulated Process y [20 50 ] Measurement Analog Out (AO0) [1 5V] USB-6008 [1 5V] Scaling f(x) = ax + b y [20 50 ]

23 1 Step 1: Ordinary Software Simulation Purpose: Create, Simulate, Control and Test the Mathematical Model Simulated Control System Hans-Petter Halvorsen

24 1a Air Heater Small-scale Laboratory Process Hans-Petter Halvorsen

25 Air Heater

26 Air Heater Hardware Heater: The air is heated by an electrical heater. The supplied power is controlled by an external voltage signal in the range 0-5 V (min power, max power). Temperature sensors: A Pt100 temperature sensor. The range is 1-5 V, and this voltage range corresponds with a linear relation to the temperature range o C (Air Heater #1-17) or 0-50 o C (Air Heater #18-32). Example of Mathematical model for the Air Heater process: T 789 = 1 θ 9 T K < u t θ > + T?@A

27 Air Heater Mathematical Model Hardware T 789 = 1 θ 9 T K < u t θ > + T?@A Where: Use, e.g., these values in the Simulations: Students: Implement and Simulate a Mathematical Model of the Air Heater using LabVIEW.

28 Air Heater in LabVIEW Heater: The air is heated by an electrical heater. The supplied power is controlled by an external voltage signal in the range 0-5 V (min power, max power). Temperature sensors: Two Pt100 temperature elements are available. The range is 1-5 V, and this voltage range corresponds to the temperature range o C (with a linear relation). Example of Mathematical Model of Air Heater implemented in LabVIEW: Note! This model is implemented in a so-called Simulation Subsystem (which is recommended!!!)

29 Simulation Subsystem A Way to structure your code, similar to SubVIs This is the recommended way to do it! You can easily reuse your Subsystems in different VIs and your code becomes more structured! Select File -> New..., Then choose Simulation Subsystem. Create your Model within the Simulation Subsystem

30 Model Simulation Example (Note! No PID Control in this Example) Note! This is just an Example! You should create your own personal Application Clear the Charts, etc. using Property Nodes Step Response Manual Control Simulation SubSystem Initialization

31 Finding Model Parameters using Trial and Error You may use, e.g., the following Parameters as a starting point, but since every Air Heater is unique, you may want to adjust these parameters. The Trial and Error Method may be an easy way to find the Parameters for your Process. Theory These values can be a good starting point: Step Respone Equal? Procedure: You run the Model and the Real Process in Parallel. Adjust the Model Parameters until the output of the Model and the Real Process is equal.

32 Trial and Error Example in LabVIEW SubVI that take care of input from DAQ device, Scaling, etc. Real Process or Black Box Model Compare Model with Real Process Initialization using Property Nodes Replace this with your model of the Air Heater

33 Air Heater Black Box Model For Online Students The Real Air Heater is only available in the Laboratory A Real Air Heater will we provided for download as a black box. Actually, it is a LabVIEW SubVI where the Block Diagram and the Process Parameters are hidden. Useful for Online Students and when you are working with the Assignment outside the Laboratory You can use it to find Model Parameters, etc. when you are not in the Laboratory

34 1b LabVIEW PID Controller Hans-Petter Halvorsen

35 PID Control of Model in LabVIEW The Simulation Loop has some drawbacks/is more complicated to use than an ordinary While Loop. If we use Simulatation Subsystems, we can use them inside a While Loop instead! - which becomes very handy! Feedback Node For real applications that involves more than just simulations (such as DAQ, File Logging, PID control of the real process, etc.), I recommend to use a While Loop instead of a Simulation Loop. Students: Implement a Control System in LabVIEW where you use the built-in PID Controller and the Mathematical Model of the Air Heater

36 PID in LabVIEW Front Panel Normally we use seconds as unit for Ti and Td (which is recommended!) But the built-in PID algorithm in LabVIEW uses minutes as unit! Cluster Block Diagram: Trick: Divide by 60 You could also put this code into a new SubVI

37 PID Parameters Find Proper PID Parameters for the system We will primary focus on PI, but you may try PID as well E.g., use one or more of the following methods: Trial and Error Skogestad Ziegler Nichols etc.

38 PID Tuning with Skogestad [Figures: F. Haugen, Advanced Dynamics and Control: TechTeach, 2010] We can set, e.g., Tc=10 sec. and c=1.5. You may use other values if these values give a poor result.

39 Congratulations! - You are finished with the Task

40 1c Lowpass Filter Hans-Petter Halvorsen

41 Lowpass Filter You should consider using a Lowpass Filter in order to reduce Noise You can use a built-in Filter in LabVIEW or download a Lowpass Filter (LabVIEW SubVI) from the Web site of this Lab Assignment You should first Test it on the Mathematical model before you apply it on the real system (next Task) See next slides for examples

42 Built-in Lowpass Filter to reduce Noise Functions palette: Express -> Signal Analysis -> Simulate Signal Functions palette: Express -> Signal Analysis -> Filter

43 Properties

44 Lowpass Filter created from Scratch You may download this Lowpass Filter (LabVIEW SubVI) from the Web page of this Lab Assignment - or create your own from scratch A golden rule is:

45 Discrete Lowpass Filter Example Lowpass Filter Transfer function: We define: Inverse Laplace the differential Equation: This gives: We use the Euler Backward method: This gives: Filter output Noisy input signal This algorithm can be easily implemented in a Programming language such as LabVIEW

46 Testing the Filter In this example we add noise to a Sine function. We then use the Measurement Filter to see if we can remove the noise afterwards. As you can see this gives good results. The filter removes the noise from the signal.

47 Creating and Using SubVIs SubVI for Lowpass Filtering SubVI for Scaling SubVI that handles the I/O between LabVIEW and the Real Process Convert from Dynamic Data

48 SubVIs

49 Congratulations! - You are finished with the Task

50 2 Step 2: HIL Simulation Purpose: Test your Hardware device before you apply it on your real system. Also useful for Training purposes. HIL with Fuji PXG5 PID Hans-Petter Halvorsen

51 Fuji PXG5 PID Controller

52 Make sure to disconnect the power cable when wiring No Food and Drink allowed when you use the Fuji PXG5 hardware, because of risk of electric shock!

53 HIL with Fuji PXG5/PXR5 PID Theory It may be very useful to test a controller function with a simulated process before the controller is applied to the real (physical) process. If the mathematical model used in the simulator is an accurate representation of the real process, you may even tune the controller parameters (e.g. the PID parameters) using the simulator.

54 HIL Simulation Setup Analog Out (Process Value) 1-5V USB Model of Process (Air Heater) AO0 GND Note!! Mathematical Model AI0+ PID Control AI0- Analog In (Control Signal) 0-5V I/O Module (USB-6008) Computer (with LabVIEW)

55 USB-6008 DAQ Always test your DAQ device before you use it in your application Loopback Test: 1. Create the simple test program as shown below. 2. Wire the AO0 and AI0 cables together. If you get the same value in the Analog Out and in the Analog In you know your device is working properly Numeric Control Should be equal Numeric Indicator Students: Make sure your DAQ device works as expected

56 Fuji PXG5 PID Simulator The Fuji PXG5 PID is only available in the Laboratory. If you work at home you may want to use a Fuji PXG5 PID Simulator. You can create your own Simulator or download this Example from the Web Page of this Lab Work. Change SV (Set Value) and PID Parameters For Online Students

57 HIL Example with Fuji PXG5 PID Simulator For Online Students In this example you can easily switch between the Real Fuji PID Controller and a Simulator

58 PXG5 PID Controller Hardware Students: It is crucial that you read the Instruction Manual carefully before you start using the Fuji PID Controller! Otherwise you may destroy it! PXG5 PID Instruction Manual: 20Controller/Background/PXG5%20Instruction%20manual%20with%20Comments.pdf

59 PXG5 PID Controller Wiring Diagram Hardware Note! 230V Be careful!! 59

60 How it works (Main Features): PXG5 PID Controller Hardware For more details, please read the PXG5 Instruction Manual!

61 How-To Change Setpoint: PXG5 - Configuration Hardware How-To Change Parameters: Channel 1: Auto-tuning Channel 2: PID Parameters

62 PXG5 - Configuration Hardware Some important Channel Settings: Channel 1: MAn = off rem = LoCl AT = off Channel 2: SvL = 20 Svh = 50 Temperature Range for Air Heater Channel 6: Pvb = 20 PvF = 50 Pvd = 0 C1r = 0-20mA

63 Test Communication between PXG5 and DAQ Device You should test the communication before you start working on the task 0 100% 0 5V Note! Set Parameter C1r in Ch6: 0-20mA. A 250 Ω resistor converts the signal to 0-5V You can choose to show voltage or Engineering units Run the PXG5 in Manual Mode (hold down the A/M button for å few seconds) We manually adjust the setpoint between 0-100% Students: It is recommended that you create such a VI in order to test the communication between LabVIEW and PXG5 PID

64 Students: Perform a HIL simulation using PXG5 and LabVIEW HIL Simulation in LabVIEW - Example You can use a Simulation Loop or a While Loop. A While loop is recommended. SubVI: In Range and Coerce Note! This is opposite of what you normally do

65 Setting PID Parameters on the PXG5 Note! PXG5 uses Proportional Band Example: Students: Find proper PID parameters using, e.g., Skogestad, Ziegler Nichols, etc.

66 PID Tuning with Skogestad [Figures: F. Haugen, Advanced Dynamics and Control: TechTeach, 2010] We can set, e.g., Tc=10 sec. and c=1.5. You may use other values if these values give a poor result.

67 PXG5 Auto-tuning 1. With the controller in manual mode (open loop control): Adjust the manual control signal so that the process output is approximately 2.5 V. 2. Set the controller in automatic mode ( closed loop control ). 3. Start Auto-tuning Note! PXG5 uses Proportional Band A lamp is blinking when the auto-tuning is running Students: Test the Auto-tuning functionality built-into the PXG5 PID. Do you get the same results?

68 Students: PXG5 Auto-tuning Execute auto-tuning. What is the resulting P-, I- and D-values? What is the value of the controller gain (Kp) that corresponds to the P-value from the auto-tuning? Is the stability of the control system OK? (excite with a step in the Setpoint/Reference Signal) Apply a step change in the reference. What is the steady-state control error? What happens to the stability of the control system if the controller mode is changed from Reverse action to Direct action? (In the controller manual, Direct action is denoted Normal mode.) Fine-tune the PID parameters if necessary.

69 Congratulations! - You are finished with the Task

70 3 Step 3: Running the Real System Purpose: Apply your Hardware in the Production System Fuju PXG5 + Real Air Heater Hans-Petter Halvorsen

71 Fuju PXG5 + Real Air Heater Industrial PID Controller Process Value 1-5V Control Signal 0-5V Students: Test the PXG5 PID Controller on the real Air Heater. Are you able to use the same PID settings you found using the Model? Test also the Auto-tuning functionality. Do you get the same parameters as using the model? Which PID parameters are best?

72 For Online Students When you are not in the Laboratory For Online Students and when you are not on the Laboratory, you can use: Fuji PXG5 PID Simulator Air Heater Black Box Model These can be downloaded from the website for this assignment

73 Fuji PXG5 PID Simulator + Air Heater Black Box Model Example For Online Students and when not on the Laboratory (You see the Block Diagram on the next slide)

74 Fuji PXG5 PID Simulator + Air Heater Black Box Model Example Fuji PXG5 PID Simulator For Online Students and when not on the Laboratory Air Heater Black Box Model

75 Fuju PXG5 + Real Air Heater + PC for Monitoring Industrial PID Controller Process Value 1-5V Trending/Monitoring the Process Value and Control Signal on the PC 0-5V Control Signal u y USB Process Value 1-5V Control Signal 0-5V PC with LabVIEW With this setup you can Monitor (Plot and Log Data to File) the Process Value and Control Signal on your PC

76 Save Data to File (Datalogging) Right-click-Properties Recommended Settings

77 Datalogging Example

78 Measurement File Data Visualization Open the File with Logged Data in e.g. Notepad: Open the File with Logged Data in MS Excel and create a Chart (Measurement Value, Control Value) Make sure to format number of Decimals 78

79 Congratulations! - You are finished with the Task

80 PID Parameters Hans-Petter Halvorsen

81 Comparison of PID Parameters Example: Kp PB [%] Ti [sec] Td [sec] Tuning Method Comment Built-in PID in LabVIEW Fuji on Model Fuji Autotuning on Model Fuji on Real Process Fuji Autotuning on Real Process... others Fill out a Table with the values you find

82 Congratulations! - You are finished with the Task

83 Congratulations! - You are finished with all the Tasks in the Assignment!

84 Hans-Petter Halvorsen, M.Sc. University College of Southeast Norway Blog: