117 lesson: let AutoTune tune the robot

The robot measures itself. It finds which way each motor turns and where the pods sit. It finds how fast it can drive and how hard it can brake. Pedro Pathing’s AutoTune does the measuring. You paste what it finds into Constants.java.

Before you start.

  • L115 is done, so the Pinpoint and its two pods are mounted and plugged in, and L050’s motor directions are set.

  • The robot, the Driver Station, a laptop that can join the robot’s Wi-Fi, and blocks to lift the robot’s wheels off the floor.

  • Clear floor for L117S040: at least 48 in ahead of the robot, 48 in to its left and 36 in to its right, plus a tile of room all around.

The step names and the messages quoted are from the tuner code in pedro/procedures/, and the address from Pedro’s Mecanum page.

the steps

L117S010: open AutoTune

AutoTune is a web page the robot serves. It is not in the Driver Station’s list of OpModes. It starts its own OpMode, called Pedro Tuning, when a step needs the robot to move.

Send. Send the code to the robot. Join the laptop to the robot’s Wi-Fi. In a browser, open http://192.168.43.1:10158.

The first time the browser talks to the robot, the operating system might ask for your permission. Please give it.

Check.

  • The page lists four tuners: Mecanum Tuner, Tests, Pinpoint Tuner and Foresight Tuner.

L117S020: find which way each motor turns

Put the robot on blocks, so its wheels spin freely.

Robot. Pick Mecanum Tuner. Type the four motor names as the Robot Configuration spells them: Front Left, Front Right, Back Left and Back Right. Each motor then spins on its own, at half power, beside a picture of which wheel it is. Say whether it spun, and whether it spun forward or reversed.

Change. At the end, AutoTune shows Java that starts public static MecanumConfig drivetrainConfig. Open Constants, in the pedro folder. Find the four lines that set the names, and put the four name lines AutoTune shows in their place. Keep manualBrakeMode and powerThreshold. AutoTune does not print them. Then open the file of the robot thisRobot names, such as Bot37523, and put the four direction lines AutoTune shows in place of its four.

Check.

  • The directions match what L050 found on blocks.

L117S030: measure the pods

The Pinpoint needs four more numbers: which way each pod counts, and how far each one sits from the middle of the robot. The x offset is how far sideways the forward pod is from the point the robot turns about, and left counts up. The y offset is how far forward the strafe pod is, and forward counts up. This robot’s are about 1.06 in and 3.36 in.

Put the robot on the floor.

Robot. Pick Pinpoint Tuner. Keep the name pinpoint and the pod type it offers. Then do the three pushes it asks for, stopping each one when you are done:

  • Push the robot forward.

  • Push the robot to the left.

  • Spin the robot half a turn on the spot, counterclockwise.

Change. Replace localizerConfig in Constants with the PinpointConfig AutoTune shows.

Check.

  • In Tests, pick Localization Test and drive with the gamepad.

  • Driving forward raises x, and strafing left raises y.

L117S040: let the robot find its speed and its brakes

This one drives itself. Clear the floor first.

Robot. Pick Foresight Tuner. Keep the distances and the speed it offers: 48 in, 30 in/s and 36 in. It drives forward and left as fast as it can, coasts to a stop, turns back and forth, spins, brakes, and steps 12 in to 24 in each way.

Change. Replace foresightConfig in Constants with the ForesightConfig AutoTune shows. Keep the five lines it does not print, from translationalConstraint to holdPointHeadingScaling.

Three of its numbers are kept twice in Constants, for the lessons’ own drivetrain. Copy each one up into its own line:

  • the number in c.coast.set(...) goes in powerPerInchPerSecond;

  • maxAchievableForwardVelocity goes in maxForwardInchesPerSecond;

  • maxAchievableStrafeVelocity goes in maxStrafeInchesPerSecond.

Check.

  • Each of the three pairs holds the same number.

L117S050: watch it drive a line

Send. Send the code again, so the new Constants is on the robot.

Robot. In Tests, pick Line Test, with the distance at 48.

Check.

  • The robot drives 48 in and stops on the line.

If it didn’t, and the Mecanum Tuner stops with this, a motor other than the one named spun, or none did:

The wrong motor spun. Check that your motors are plugged into the correct ports, and that they are configured correctly. Then, try again.

It is the message for an answer of No to “Did the front left motor spin?”, read from MecanumTuner.java. Swap two motor names and each of those motors is given the other’s direction, so both wheels turn backwards. L050’s checks on blocks cannot tell that from a backwards wheel. This one can.

If it didn’t, and x and y swap over in the Localization Test, the two pods are in each other’s sockets. L115S010 is where that gets fixed, and no tuning works around it.

If it didn’t, and the robot brakes late or never holds still after L117S040, check that the five hold lines are still in foresightConfig.

What you just did. Every number in Constants.java and the robot’s own file either came off this robot or is waiting to. AutoTune measures the ones that need the robot driving itself. L195 measures the two it does not: ticks per inch and the turn radius.

Where next. L120 compares the Pinpoint with the drive encoders and logs both.