FRC #1018 Robot speed simulation 2019

AttachedRobotSpeedWork_190320.xlsx (4.5 MB)

The attached spreadsheet captures what we considered in selecting our drivetrain components for this season. Rows 65 and 66 on the UserInterface page show what we used in 2018 (MiniCIM based) as background.

The spreadsheet also includes a table of changes that will translate the condition to correspond with a hardware test conducted in late 2017. This was the basis for the slip computations that are built into the simulation calculations.

Please comment if you are so motivated.

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Please explain cell B23 (Transition index), G12 (Selected operating point index), and B36 (Human command), and how can I change the ratio for custom gearbox option?


Transition index: This is intended to support simulation for shifting gearbox models. In this case the numerical index (cell C23) marks the shifting point in the simulation.

Selected operating point: This is intended to provide a snapshot of the system values at a particular time-step. Changing cell H12 will update the time point, the data values in H14:H34 will then also be updated.

Human command: This is intended to model the extent of the command from the driver, I think this should remain 100%; I.e. “go fast as I can”.

Your question is modeling of custom gearboxes.
Look at the Gearboxes.
On that page you will see all of the modeled gearboxes.
At present, there is one space identified as “custom”. The present custom gearbox defines a single stage gear reduction.
Most likely way to model a custom gearbox is to start with an existing gearbox and start changing the gear selections - this will change the gear ratio. Be careful! Not all selections can be built!!

Once you have updated the gear ratio: go back to the UserInterface tab, Change both the Low Speed (cell C20) and the High speed (C28) to the gearbox you want to consider.

There are other ways to do this, but I think this is the most straight forward.

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RobotSpeedWork_191106.xlsx (4.3 MB)
Simulation product updated to include Falcon and Venom motor solutions.
This enables comparison of motor selections and gearbox selections.
Simulation does not support motor combinations; all drive train motors must be the same.

If, in the course of experimenting, a purple trace shows up in the Velocity plot, the robot wheels are likely slipping on the drive surface; reduce the motor current limit to reduce the drive torque.

Velocity, Voltage, and Current time responses are plotted.
Individual time-step values can also be examined to further understand specific operating points.

RobotSpeedWork_200417.xlsx (4.3 MB)
The purpose for this post is to update the posting data.
The attached file represents the design point utilized for the 2020 robot design.
No design was performed in 2021, so no work has been lost.