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[wpimath] Rename ChassisSpeeds.fromDiscreteSpeeds() to discretize() (#5616)

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This better reflects what's actually going on mathematically.
This commit is contained in:
Tyler Veness
2023-09-08 20:14:59 -07:00
committed by GitHub
parent 8e05983a4a
commit a9ab08f48b
14 changed files with 101 additions and 73 deletions
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56
wpimath/src/main/native/include/frc/kinematics/ChassisSpeeds.h
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@@ -39,52 +39,54 @@ struct WPILIB_DLLEXPORT ChassisSpeeds {
units::radians_per_second_t omega = 0_rad_per_s;
/**
* Converts from a chassis speed for a discrete timestep into chassis speed
* for continuous time.
* Disretizes a continuous-time chassis speed.
*
* The difference between applying a chassis speed for a discrete timestep vs.
* continuously is that applying for a discrete timestep is just scaling the
* velocity components by the time and adding, while when applying
* continuously the changes to the heading affect the direction the
* translational components are applied to relative to the field.
* This function converts a continous-time chassis speed into a discrete-time
* one such that when the discrete-time chassis speed is applied for one
* timestep, the robot moves as if the velocity components are independent
* (i.e., the robot moves v_x * dt along the x-axis, v_y * dt along the
* y-axis, and omega * dt around the z-axis).
*
* This is useful for compensating for translational skew when translating and
* rotating a swerve drivetrain.
*
* @param vx Forward velocity.
* @param vy Sideways velocity.
* @param omega Angular velocity.
* @param dt The duration of the timestep the speeds should be applied for.
*
* @return ChassisSpeeds that can be applied continuously to produce the
* discrete ChassisSpeeds.
* @return Discretized ChassisSpeeds.
*/
static ChassisSpeeds FromDiscreteSpeeds(units::meters_per_second_t vx,
units::meters_per_second_t vy,
units::radians_per_second_t omega,
units::second_t dt) {
static ChassisSpeeds Discretize(units::meters_per_second_t vx,
units::meters_per_second_t vy,
units::radians_per_second_t omega,
units::second_t dt) {
Pose2d desiredDeltaPose{vx * dt, vy * dt, omega * dt};
auto twist = Pose2d{}.Log(desiredDeltaPose);
return {twist.dx / dt, twist.dy / dt, twist.dtheta / dt};
}
/**
* Converts from a chassis speed for a discrete timestep into chassis speed
* for continuous time.
* Disretizes a continuous-time chassis speed.
*
* The difference between applying a chassis speed for a discrete timestep vs.
* continuously is that applying for a discrete timestep is just scaling the
* velocity components by the time and adding, while when applying
* continuously the changes to the heading affect the direction the
* translational components are applied to relative to the field.
* This function converts a continous-time chassis speed into a discrete-time
* one such that when the discrete-time chassis speed is applied for one
* timestep, the robot moves as if the velocity components are independent
* (i.e., the robot moves v_x * dt along the x-axis, v_y * dt along the
* y-axis, and omega * dt around the z-axis).
*
* @param discreteSpeeds The speeds for a discrete timestep.
* This is useful for compensating for translational skew when translating and
* rotating a swerve drivetrain.
*
* @param continuousSpeeds The continuous speeds.
* @param dt The duration of the timestep the speeds should be applied for.
*
* @return ChassisSpeeds that can be applied continuously to produce the
* discrete ChassisSpeeds.
* @return Discretized ChassisSpeeds.
*/
static ChassisSpeeds FromDiscreteSpeeds(const ChassisSpeeds& discreteSpeeds,
units::second_t dt) {
return FromDiscreteSpeeds(discreteSpeeds.vx, discreteSpeeds.vy,
discreteSpeeds.omega, dt);
static ChassisSpeeds Discretize(const ChassisSpeeds& continuousSpeeds,
units::second_t dt) {
return Discretize(continuousSpeeds.vx, continuousSpeeds.vy,
continuousSpeeds.omega, dt);
}
/**