Modeling of sprocket and rackbar in Simscape

I modeling a rack bar and sprocket mechanism used for hauling the underground Shearer machines. The sprocket is a non involute and, the 2D coordinates of rack and sprocket are available. Is it possible to import the 2D profile of both rack and sprocket and simulate the mechanism in Simscape Multibody and could you provide some input of how to model it?

Answer 1

[albara]

Yes, it's possible to import the 2D profiles of both the rack and sprocket and simulate the mechanism in Simscape Multibody. Here's a step-by-step guide on how to model the rack and sprocket mechanism in Simscape:

1. Prepare the 2D profiles: Make sure that the 2D profiles of the rack and sprocket are in a suitable file format, such as .dxf, .step, or .igs. If they are not, you might need to convert them using a CAD software like SolidWorks, Autodesk Inventor, or Fusion 360.
2. Import the 2D profiles to Simscape Multibody: a. Open MATLAB and start a new Simscape Multibody model by typing simmechanics in the command window. b. In the Simscape Multibody model, go to the 'File' menu, and click on 'Import'. c. Select 'CAD' and then choose the appropriate file format for your 2D profiles. d. Browse for the files containing the rack and sprocket profiles and import them into the model.
3. Assemble the mechanism: After importing the 2D profiles into the model, you need to assemble the rack and sprocket mechanism by defining the appropriate joints and constraints.a. Add a 'Prismatic' joint between the ground and the rack to allow the rack to move linearly along the horizontal axis. b. Add a 'Revolute' joint between the ground and the sprocket to allow the sprocket to rotate about its center. c. Use a 'Contact Force' block to define the contact between the teeth of the rack and sprocket. You can find this block in the 'Simscape > Multibody > Forces and Torques' library. Connect the 'Contact Force' block to the rack and sprocket body nodes.
4. Configure contact parameters: Set the contact parameters such as stiffness, damping, and friction coefficients in the 'Contact Force' block to reflect the real-world behavior of the mechanism.
5. Apply actuation and loads: Apply appropriate actuation to the sprocket (e.g., a torque input) and any external forces acting on the rack (e.g., due to the weight of the underground Shearer machines).
6. Configure the solver settings: In the 'Model Configuration Parameters' window, set the 'Solver' to 'Variable-step' and choose a suitable solver, such as 'ode15s', to handle the potentially stiff dynamics of the system.
7. Run the simulation: Connect the necessary sensing, visualization, and output blocks, and run the simulation to observe the behavior of the rack and sprocket mechanism.

Remember that the 2D profiles should be extruded to 3D before importing them to Simscape Multibody. This can be done in the CAD software you used to create or convert the files. Additionally, you can use the Simscape Multibody Link plug-in to import CAD assemblies directly from SolidWorks, Inventor, or other supported CAD software.

Important: There may be some mistakes in this answer Experts can tell if there are any mistakes and you might find better answer

[Dilunath Hareendranath]

Thanks for the detailed explanation. It is very helpful