How to create a more accurate gearbox following from the powertrain matlab tutorial

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Al-Amin Miah 2017-2-28

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https://ww2.mathworks.cn/matlabcentral/answers/327224-how-to-create-a-more-accurate-gearbox-following-from-the-powertrain-matlab-tutorial

评论：彬魏 2021-10-9

As part of a project, I am modelling my university's formula student car on Simulink using the Simscape driveline package. I have followed the mathworks tutorials to create a drivetrain, and I am now amending the model so that it is a more accurate representation of my university car.

Our car is a 5 speed manual Honda CBR600.

I am starting off simple and then aiming to create a more complex model. I have parameterised the generic engine block to match the power of the car and calculated the car weight, etc. Now I would like to make the gear change more accurate. At the moment, when the gear changes, there is an instantaneous jump of about 5mph (as shown on the bottom of the graph about 5 seconds and 10 seconds in), which is inaccurate. I have studied the Mathwork examples, specifically the 'sdl_vehicle_manual_transmission' and 'sdl_transmission_5spd' to try and replicate that for my model, but it hasn't worked. I would like the model to increase speed upon changing gears without an instantaneous jump. What would be the next steps in order to achieve this?

Any help will be appreciated. Thank you in advance.

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彬魏 2021-10-9

Student Competition: Physical Modeling Training Part 4: Powertrain Modeling

https://www.mathworks.com/academia/student-competitions/physical-modeling-training.html

I want to know how the gear subsystem is modeled. Is there a video about it

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Answer 1

Christoph Hahn 2017-3-1

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Hi Al-Amin Miah,

I was able to reproduce what you are seeing. I had to use an ideal torque source instead of the generic engine because your model didn't include the tabulated torque data.

Changing the gear ratio all of a sudden will change the rotational speed of your shaft all of a sudden. That's physics. See here an example with the same phenomenon in the documentation: LINK .

Increasing inertia will reduce the effect. You could e.g. increase your car's mass. What I did to illustrate is I ran the model with a certain shaft inertia (block right before gear subsystem) and then with intertia*10. You will see that the fraction of the sudden speed change compared to the entire speed change get lower.

Hope that helps.

Cheers Christoph