How to check the outputs of the Incremental Shaft Encoder in Simulink?

There is a problem coming in checking the outputs of the incremental shaft encoder in Simulink.

[Ameer Hamza]

How are you reading the values?

[Ayush Srivastava]

Actually I have to connect the output of the shaft encoder to the input of the quadrature decoder so, there is a problem coming while connection.

[Ameer Hamza]

Are you reading the values from some external hardware? Can you share the simple model which you are trying to run?

[Ayush Srivastava]

In this File the problem is coming in the connection.

Answer 1

[Ameer Hamza]

Since you are using blocks from simscape multibody, which have different signals as compared to normal signals of Simulink. You cannot connect signals from two different types with each other directly. You need to add some appropriate blocks to make the signals compatible. See the attached simulink file for the example on how to connect these two signals.

[Ayush Srivastava]

Okk I got it.......thank you for the answer.

[Ayush Srivastava]

Again there is a problem coming in the connection although I am using a Voltage sensor compatible block for this.

I want to know what is the basic principle behind connecting the electrical elements(like for connecting PWM generator output) with the other electrical elements(to H-Bridge converter input) and how to connect these elements with other electrical elements .

I am attaching the two files here.

[Ameer Hamza]

Ayush, These are few rules which will help you pick the correct blocks.

1. Simscape signals are different then the normal simulink signals. We need to use converters (PS-Simulink and Simulink-PS blocks) to connect them.
2. In simscape, there are several libraries. Blocks in each library have special conservative ports and physical signal port. For example, look at this block from simscape electrical . It has two voltage conservative port (marked with small dots), and one physical signal port marked with triangle. The voltage conservative port can only be connected to other blocks in same library (in this case simscape electrical, they cannot be connected with simscape mechanical or even simscape power electronics).
3. Even for special conservative ports, only output and input can be connected. Input - Input or output - output will not connect.
4. Since conservative ports are confined within their own library. Only physical signal ports can be connected with the converters mentioned in point 1. (Remember my solution to your original question)
5. You can also use physical signal ports (marked with triangle) to connect blocks from different simscape libraries. For example, rotational motion sensor for simscape mechanical, and controlled voltage source from simscape electrical can be connected through this. Both these blocks have physical ports. These are use to transfer signals from one library to the other.
6. You can look at the documentation of the block. Mostly it mentions the type of each port and how it can be connected.

You mentioned "I am using a Voltage sensor compatible block for this". Voltage sensor block outputs a physical signal, but you need an electrical signal as output. According to point 2 above, you needed a voltage source.

I corrected the problem with the simscape blocks in ee_motor_dc_pwm.slx, however, there was another error which I also solved. The attached file also contains a comment along with the new block I connected.

For file Simple_IGBT_model.slx, i was not sure about your circuit diagram, so i just connected blocks which seems appropriate. I also fixed some other issues. If the blocks are not connected according to your circuit diagram then you can change them by following above rules.

[Ayush Srivastava]

I think you have not attached the file that you have mentioned above.

[Ameer Hamza]

Sorry, I forgot. Check the updated comment.

[Ayush Srivastava]

Why you have connected the delay element in the feedback nerwork?

[Ameer Hamza]

Because the actual circuit created an algebraic loop, which Simulink couldn't resolve, if you remove this block, it will give an error. Refer to answer on this question for more detailed discussion: https://www.mathworks.com/matlabcentral/answers/95310-what-are-algebraic-loops-in-simulink-and-how-do-i-solve-them

[Ayush Srivastava]

Ok, thanks for the answer.

[Ayush Srivastava]

Hi,

Actually there is a problem coming in the simulation of the speed control measurement of the DC motor in the simulink.

The Speed is suddenly changes in the waveform and I think the speed waveform or estimation in the simulink is not appropriate.

I am attaching the waveforms and the circuit diagram for the reference.

[Ameer Hamza]

Ayush, I am nor sure what is causing this issue here. This problem requires knowledge about the working of DC motor and its mathematical model, and I don't have much experience with it. However, I can see that this model uses a discontinuous signal, such as PWM signal, encoder, and decoder, which can cause difficulties for the Simulink solver (Also obvious from slow simulation speed). I have attached a revised model by removing these blocks and replacing them with equivalent continuous blocks. This equivalent block may not be helpful for your purpose, but it gives a general idea about how to handle such issues in Simulink.

[Ayush Srivastava]

But my physical model also comprises the components that I have attached in the previous file. So, I can't remove these components.