Speeding calibration

As part of our commitment to delivering exceptional experiences, each participant will receive a finely assembled RC car. Our dedicated assembly line has crafted these cars with precision, ensuring that they’re ready for action right out of the box.

There might be minor variations in the speeding calibration due to the manual assembly process. This isn’t a flaw, but a proof to the individual attention each car has received. For instance, while you might set the car’s speed to 10 cm/s, it might be moving at, say, 10.5 cm/s in reality.

The Solution

To enhance your experience and ensure consistent performance, we’ve deduced a mathematical solution to address these minor calibration variations…

Required Tools:

To accurately measure the real speed of the car, it’s essential to have the right tools on hand and to follow the steps below:

  1. Ruler: For precise measurements.

  2. Two markers:

    1. One for the initial position of the car.

    2. One for the final position of the car.

Measuring Procedure:

  1. Place the first marker underneath the midpoint of the rear axle when the car is at point 0.

  2. Utilize Command #9 to establish the tested speed for a specified duration. This command is structured to precisely control the vehicle’s velocity over a designated time interval.

  3. Place the second marker underneath the midpoint of the rear axle at the final position.

  4. Ensure that the starting and final positions are on the same straight line.

  5. Use the ruler to measure the distance between the two markers.

  6. Use this value in the formula below.

    \[S = \frac{d}{t}\]
    \[\text{where:}\]
    \[d = \text{measured distance}\]
    \[t = \text{provided time}\]

By following these steps, you’ll obtain an accurate measurement of the car’s speeding in cm/s. Ensure to perform these measurements in a stable environment without disturbances for the most accurate results.

Fine tune the speeding system

To fine-tune the speeding of your RC car, we focus on the following main parameter:

step_value parameter

  • In situations where the velocity system response is either below or above the expected value during testing, this parameter should be adjusted. For example, when testing 10 cm/s for 10 seconds and getting distances like 105 or 95, adjustments are needed.

Adjusting the Step Value parameter

To fine-tune the velocity system responsiveness, users can use this formula:

\[NSV = CSV + \Delta SV\]
\[\text{where:}\]
\[NSV = \text{New Step Value}\]
\[CSV = \text{Current Step Value}\]
\[\Delta SV = \text{Change in Step Value}\]

ΔSV can be calculated as:

\[\Delta SV = -\log_{10} \left( \frac{S}{S_{set}} \right) \times CSV\]
\[\text{where:}\]
\[S = \text{Actual speed (calculated previously)}\]
\[S_{set} = \text{Speeding set value (the desired target for speeding)}\]

Update predefined values for Steering

Operational example: After conducting tests for the 10 cm/s value and determining the appropriate step_value value, you must update it in the following variable:

const float speedValuesP[25] = {4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, 20.0, 21.0, 22.0, 26.0, 30.0, 35.0, 40.0, 45.0, 50.0};
const float speedValuesN[25] = {-4.0, -5.0, -6.0, -7.0, -8.0, -9.0, -10.0, -11.0, -12.0, -13.0, -14.0, -15.0, -16.0, -17.0, -18.0, -19.0, -20.0, -21.0, -22.0, -26.0, -30.0, -35.0, -40.0, -45.0, -50.0};
const float stepValues[25] = {0.00107, 0.00088, 0.00076, 0.00067, 0.0006, 0.00055, 0.00051, 0.00047, 0.00043, 0.00041, 0.00039, 0.00037, 0.00035, 0.00034, 0.00033, 0.00032,
                             0.0003, 0.00029, 0.00028, 0.00025, 0.00024, 0.00021, 0.00019, 0.00018, 0.00017};

Embedded_Platform\include\drivers\speedingmotor.hpp

You must pay attention to the position within the array of the values. If 10 has an index of 2 in the positive values array, it should have the same index in the negative values array. The same applies to the step_value value.

Utilize this guidance and the formulas provided to ensure that the speeding mechanism is adjusted appropriately for optimal performance. Remember, accurate speeding calibration is crucial for optimal performance, so ensure you follow the above steps carefully.