How MIL,SIL is a Closed Loop Testing ?

Closed Loop Testing

Answer 1

[jagpreet makkad]

I will give you an overall idea about the MIL SIL PIL and HIL. I have read it somewhere and sharing it with u. By reading this u will get the clear idea of what actually is plant model and what is controller model and how design testing flow works.

If you are designing the controller from scratch then you develop the model of the plant and controller (say using Matlab,SIMULINK) and use MIL to verify or test whether it is implementable. Whereas if you already have the controller model you can skip MIL and go to SIL.

Once your model is verified, the next stage is SIL where you develop a software/HDL code depending on the processor or FPGA you plan to use for final hardware implementation and run the simulations for the controller model (with the plant still a software model) with this code to verify it. If you experience any glitches you may have to go back to MIL and make necessary changes. If you have a model which has been tested for SIL also then you can skip this and go directly to PIL.

Once your controller is verified for its SIL implementation, you proceed to the next stage i.e., PIL where you load the developed code onto the processor/FPGA and run the simulations on the modeled plant for verification. If there are glitches then go back to your code, SIL or MIL and rectify them. If you have an FPGA or a processor ready then you can skip this and go directly to HIL.

Once your plant model has been verified using PIL, now you can replace the plant model with the original hardware ,say lab model, (say,if its a DC motor whose speed controller is being designed, then controller is in FPGA/processor which is now interfaced to the DC motor by connecting the inputs and outputs/states at the right points of sensors/transducers) and conduct the HIL test for verification.

Once you complete all the above tests, your controller is said to be ready for hardware implementation.

If supposing you give National Instruments your plant specifications and controller requirements, they may design an FPGA based on Labview and give it to you.In that case you can directly run the HIL and verify.

[Sriharsha]

Hi, I want to perform SIL MIL and PIL testing. I dont have any experience with testing. Can we buy any hardware and start learning the HIL/PIL testing?

Kindly help me.

[Aluri Pramod Kumar]

MIL and SIL testing environment you can create it in your matlab environment. coming to PIL testing environment , Target link is providing interfaces with Matlab to different processors for more information you can check it in Dspace website.

[Manish Gawade]

Good one :)

[Nathan Morrison]

Hi,

please note that when testing the embedded system on HIL level the software runs on the final controller (hardware device). However, the environment around the hardware device is still a simulated one.

The main purpose with the HIL Simulation is to test the hardware device on a simulator before we implement it on the real process (the real plant, that is the dynamic system being controlled).

[Ahmed Gad]

HIL is a test before using the real hardware I guess.

[SHASHWAT KANHAIYA]

i Think, in this answer Plant model has been replaced with controller model and viceversa.

pls correct me if i misunderstood

Answer 2

[Gaurav Shukla]

Broadly speaking when you create a controller model for validation of the logic you connect the output of your controller to a plant model and output from plant is fed back to controller. Thereby creating a closed loop.

For SIL you replace the model logic for your controller with the generated code rest all process remains the same.

[Aluri Pramod Kumar]

Hi gaurav than you for your answer..

What is the Plant Model can you please explain it in brief?

[Apurva Bhide]

Plant model is the model of expected behavior of system you are making controller for. For eg: you model the overall behavior (response)of car and call it plant model. Then one can use this model and use the controller model to test whether the expected output is received with the current implementation of controller.

[xian zhao]

since both PIL and HIL use a simulation to test，why don't we perform only Pil or HIL?

[Jesús]

We don`t perform only PIL and HIL, because PIL and HIL test different things.

• PIL is used to check the code of the processor against a Matlab/Simulink model of the plant. The connection between the processsor and the Matlab model are digital signals.
• HIL is used to check the final hardware of the controller and the final processor code. The connection between the processor and the Matlab model are hardware electronics.

For example, in case of the development of an ECU of a car:

• PIL could be a prototype board using same processor than the final ECU, connected to a PC running matlab model and communicating by ethernet.

• HIL will consist of the final ECU with final hardware electronics, connected to the HIL simulator using the final connector of the ECU. The HIL simulator includes a complete model of dynamics of the car, other ECUs and hardware for simulating the sensor and actuators connected to the ECU. In addition, the advanced HIL simulator test the electronics injecting hardware errors, as short circuits or break of cables at the conector of the ECU. So, the HIL testing check the hardware of the ECU and the interaction with other componentes.

Answer 3

[Ahmed Gad]

You can check the following link to know about everyone of them.

https://www.mathworks.com/matlabcentral/answers/440277-what-is-mil-sil-pil-hil-and-how-do-they-integrate-in-model-based-design-approach