07 / Motion Profiling

Motion Profile Concepts

Understand position, velocity, acceleration, and why smooth targets matter.

55 minControlMotion Profiling

You will

01Explain why instant target jumps cause harsh motion.
02Read a trapezoidal velocity profile.
03Connect max velocity and acceleration to robot consistency.

Why Motion Profile Concepts matters

This lesson is about planning motion before controlling it. A profile turns a sudden target jump into a time-based path of positions, velocities, and accelerations that a controller can follow more gently.

Starting point

Profiles create moving targets

Instead of commanding a mechanism to teleport from one setpoint to another, a profile tells it where it should be at each time. PID then follows that moving target.

Smooth motion improves repeatability

The slide deck notes motion profiling as a consistency fix. Limiting acceleration reduces jerk, wheel slip, belt stretch, and mechanism bounce.

Build path

Draw the motion first, then code it. Students should label acceleration, cruise, deceleration, total time, and target position before implementing a profiled mechanism. The code should regenerate the profile only when the target changes, then follow the current profile state each loop.

For this specific lesson, students should first restate the goal in robot terms, then identify the value or behavior they expect to observe, then run the smallest test that proves the idea. The lesson should feel like a guided lab: predict, run, observe, explain, and only then extend.

ProfileVocabulary.java · Java

ProfileConstraints constraints = new ProfileConstraints(
    900.0,  // max velocity ticks/s
    1800.0, // max acceleration ticks/s^2
    2200.0  // max deceleration ticks/s^2
);

AsymmetricMotionProfile profile =
    new AsymmetricMotionProfile(currentTicks, targetTicks, constraints);

Debugging and failure modes

Profiled systems fail when the requested motion is physically unrealistic or when the profile is restarted every loop. Saturated output, growing error, overshoot, and late arrival all point to different fixes. The lesson should make students name the failure mode before touching constants.

Checks

The profile starts at the current mechanism position.
Velocity does not jump instantly to maximum.
Acceleration and deceleration limits are written with units.

Check your understanding

Module check

What does a motion profile calculate over time?

0 of 1 answered

References

Game Manual 0Community FTC programming, control, and robot design reference.FTC DashboardTelemetry, config variables, and tuning support.