Struct PdController

pub struct PdController {
    pub lin_kp: Vector<f32>,
    pub lin_kd: Vector<f32>,
    pub ang_kp: AngVector<f32>,
    pub ang_kd: AngVector<f32>,
    pub axes: AxesMask,
}

A Proportional-Derivative (PD) controller.

This is useful for controlling a rigid-body at the velocity level so it matches a target pose.

This is a PID controller without the Integral part to keep the API immutable, while having a behaviour generally sufficient for games.

Fields

lin_kp: Vector<f32>

The Proportional gain applied to the instantaneous linear position errors.

This is usually set to a multiple of the inverse of simulation step time (e.g. 60 if the delta-time is 1.0 / 60.0).

lin_kd: Vector<f32>

The Derivative gain applied to the instantaneous linear velocity errors.

This is usually set to a value in [0.0, 1.0] where 0.0 implies no damping (no correction of velocity errors) and 1.0 implies complete damping (velocity errors are corrected in a single simulation step).

ang_kp: AngVector<f32>

The Proportional gain applied to the instantaneous angular position errors.

This is usually set to a multiple of the inverse of simulation step time (e.g. 60 if the delta-time is 1.0 / 60.0).

ang_kd: AngVector<f32>

The Derivative gain applied to the instantaneous angular velocity errors.

This is usually set to a value in [0.0, 1.0] where 0.0 implies no damping (no correction of velocity errors) and 1.0 implies complete damping (velocity errors are corrected in a single simulation step).

axes: AxesMask

The axes affected by this controller.

Only coordinate axes with a bit flags set to true will be taken into account when calculating the errors and corrections.

Implementations

impl PdController

pub fn new(kp: f32, kd: f32, axes: AxesMask) -> PdController

Initialized the PD controller with uniform gain.

The same gain are applied on all axes. To configure per-axes gains, construct the PdController by setting its fields explicitly instead.

Only the axes specified in axes will be enabled (but the gain values are set on all axes regardless).

pub fn linear_rigid_body_correction( &self, rb: &RigidBody, target_pos: Point<f32>, target_linvel: Vector<f32>, ) -> Vector<f32>

Calculates the linear correction from positional and velocity errors calculated automatically from a rigid-body and the desired positions/velocities.

The unit of the returned value depends on the gain values. In general, kd is proportional to the inverse of the simulation step so the returned value is a linear rigid-body velocity change.

pub fn angular_rigid_body_correction( &self, rb: &RigidBody, target_rot: Rotation<f32>, target_angvel: AngVector<f32>, ) -> AngVector<f32>

Calculates the angular correction from positional and velocity errors calculated automatically from a rigid-body and the desired positions/velocities.

The unit of the returned value depends on the gain values. In general, kd is proportional to the inverse of the simulation step so the returned value is an angular rigid-body velocity change.

pub fn rigid_body_correction( &self, rb: &RigidBody, target_pose: Isometry<f32>, target_vels: RigidBodyVelocity, ) -> RigidBodyVelocity

Calculates the linear and angular correction from positional and velocity errors calculated automatically from a rigid-body and the desired poses/velocities.

The unit of the returned value depends on the gain values. In general, kd is proportional to the inverse of the simulation step so the returned value is a rigid-body velocity change.

pub fn correction( &self, pose_errors: &PdErrors, vel_errors: &PdErrors, ) -> RigidBodyVelocity

Calculates the linear and angular correction from the given positional and velocity errors.

The unit of the returned value depends on the gain values. In general, kd is proportional to the inverse of the simulation step so the returned value is a rigid-body velocity change.

Trait Implementations

impl Clone for PdController

fn clone(&self) -> PdController

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PdController

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for PdController

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for PdController

fn eq(&self, other: &PdController) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for PdController

impl StructuralPartialEq for PdController