Files
rapier/src/dynamics/solver/joint_constraint/revolute_velocity_constraint.rs
Crozet Sébastien 0eec28325e Fix warnings.
2021-02-22 14:20:06 +01:00

512 lines
18 KiB
Rust

use crate::dynamics::solver::{AnyJointVelocityConstraint, DeltaVel};
use crate::dynamics::{
IntegrationParameters, JointGraphEdge, JointIndex, JointParams, RevoluteJoint, RigidBody,
};
use crate::math::{AngularInertia, Real, Rotation, Vector};
use crate::na::UnitQuaternion;
use crate::utils::{WAngularInertia, WCross, WCrossMatrix};
use na::{Cholesky, Matrix3x2, Matrix5, Vector5, U2, U3};
#[derive(Debug)]
pub(crate) struct RevoluteVelocityConstraint {
mj_lambda1: usize,
mj_lambda2: usize,
joint_id: JointIndex,
r1: Vector<Real>,
r2: Vector<Real>,
inv_lhs: Matrix5<Real>,
rhs: Vector5<Real>,
impulse: Vector5<Real>,
motor_inv_lhs: Real,
motor_rhs: Real,
motor_impulse: Real,
motor_max_impulse: Real,
motor_angle: Real, // Exists only to write it back into the joint.
motor_axis1: Vector<Real>,
motor_axis2: Vector<Real>,
basis1: Matrix3x2<Real>,
basis2: Matrix3x2<Real>,
im1: Real,
im2: Real,
ii1_sqrt: AngularInertia<Real>,
ii2_sqrt: AngularInertia<Real>,
}
impl RevoluteVelocityConstraint {
pub fn from_params(
params: &IntegrationParameters,
joint_id: JointIndex,
rb1: &RigidBody,
rb2: &RigidBody,
joint: &RevoluteJoint,
) -> Self {
// Linear part.
let anchor1 = rb1.position * joint.local_anchor1;
let anchor2 = rb2.position * joint.local_anchor2;
let basis1 = Matrix3x2::from_columns(&[
rb1.position * joint.basis1[0],
rb1.position * joint.basis1[1],
]);
let basis2 = Matrix3x2::from_columns(&[
rb2.position * joint.basis2[0],
rb2.position * joint.basis2[1],
]);
let basis_projection2 = basis2 * basis2.transpose();
let basis2 = basis_projection2 * basis1;
let im1 = rb1.effective_inv_mass;
let im2 = rb2.effective_inv_mass;
let ii1 = rb1.effective_world_inv_inertia_sqrt.squared();
let r1 = anchor1 - rb1.world_com;
let r1_mat = r1.gcross_matrix();
let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
let r2 = anchor2 - rb2.world_com;
let r2_mat = r2.gcross_matrix();
let mut lhs = Matrix5::zeros();
let lhs00 =
ii2.quadform(&r2_mat).add_diagonal(im2) + ii1.quadform(&r1_mat).add_diagonal(im1);
let lhs10 = basis2.tr_mul(&(ii2 * r2_mat)) + basis1.tr_mul(&(ii1 * r1_mat));
let lhs11 = (ii1.quadform3x2(&basis1) + ii2.quadform3x2(&basis2)).into_matrix();
// Note that Cholesky won't read the upper-right part
// of lhs so we don't have to fill it.
lhs.fixed_slice_mut::<U3, U3>(0, 0)
.copy_from(&lhs00.into_matrix());
lhs.fixed_slice_mut::<U2, U3>(3, 0).copy_from(&lhs10);
lhs.fixed_slice_mut::<U2, U2>(3, 3).copy_from(&lhs11);
let inv_lhs = Cholesky::new_unchecked(lhs).inverse();
let lin_rhs = (rb2.linvel + rb2.angvel.gcross(r2)) - (rb1.linvel + rb1.angvel.gcross(r1));
let ang_rhs = basis2.tr_mul(&rb2.angvel) - basis1.tr_mul(&rb1.angvel);
let rhs = Vector5::new(lin_rhs.x, lin_rhs.y, lin_rhs.z, ang_rhs.x, ang_rhs.y);
/*
* Motor.
*/
let motor_axis1 = rb1.position * *joint.local_axis1;
let motor_axis2 = rb2.position * *joint.local_axis2;
let mut motor_rhs = 0.0;
let mut motor_inv_lhs = 0.0;
let mut motor_angle = 0.0;
let motor_max_impulse = joint.motor_max_impulse;
let (stiffness, damping, gamma, keep_lhs) = joint.motor_model.combine_coefficients(
params.dt,
joint.motor_stiffness,
joint.motor_damping,
);
if stiffness != 0.0 {
motor_angle = joint.estimate_motor_angle(&rb1.position, &rb2.position);
motor_rhs += (motor_angle - joint.motor_target_pos) * stiffness;
}
if damping != 0.0 {
let curr_vel = rb2.angvel.dot(&motor_axis2) - rb1.angvel.dot(&motor_axis1);
motor_rhs += (curr_vel - joint.motor_target_vel) * damping;
}
if stiffness != 0.0 || damping != 0.0 {
motor_inv_lhs = if keep_lhs {
crate::utils::inv(
motor_axis2.dot(&ii2.transform_vector(motor_axis2))
+ motor_axis1.dot(&ii1.transform_vector(motor_axis1)),
) * gamma
} else {
gamma
};
motor_rhs /= gamma;
}
/*
* Adjust the warmstart impulse.
* If the velocity along the free axis is somewhat high,
* we need to adjust the angular warmstart impulse because it
* may have a direction that is too different than last frame,
* making it counter-productive.
*/
let mut impulse = joint.impulse * params.warmstart_coeff;
let axis_rot = Rotation::rotation_between(&joint.prev_axis1, &motor_axis1)
.unwrap_or_else(UnitQuaternion::identity);
let rotated_impulse = basis1.tr_mul(&(axis_rot * joint.world_ang_impulse));
impulse[3] = rotated_impulse.x * params.warmstart_coeff;
impulse[4] = rotated_impulse.y * params.warmstart_coeff;
let motor_impulse = na::clamp(joint.motor_impulse, -motor_max_impulse, motor_max_impulse)
* params.warmstart_coeff;
RevoluteVelocityConstraint {
joint_id,
mj_lambda1: rb1.active_set_offset,
mj_lambda2: rb2.active_set_offset,
im1,
ii1_sqrt: rb1.effective_world_inv_inertia_sqrt,
basis1,
basis2,
im2,
ii2_sqrt: rb2.effective_world_inv_inertia_sqrt,
impulse,
inv_lhs,
rhs,
r1,
r2,
motor_rhs,
motor_inv_lhs,
motor_max_impulse,
motor_axis1,
motor_axis2,
motor_impulse,
motor_angle,
}
}
pub fn warmstart(&self, mj_lambdas: &mut [DeltaVel<Real>]) {
let mut mj_lambda1 = mj_lambdas[self.mj_lambda1 as usize];
let mut mj_lambda2 = mj_lambdas[self.mj_lambda2 as usize];
let lin_impulse1 = self.impulse.fixed_rows::<U3>(0).into_owned();
let lin_impulse2 = self.impulse.fixed_rows::<U3>(0).into_owned();
let ang_impulse1 = self.basis1 * self.impulse.fixed_rows::<U2>(3).into_owned();
let ang_impulse2 = self.basis2 * self.impulse.fixed_rows::<U2>(3).into_owned();
mj_lambda1.linear += self.im1 * lin_impulse1;
mj_lambda1.angular += self
.ii1_sqrt
.transform_vector(ang_impulse1 + self.r1.gcross(lin_impulse1));
mj_lambda2.linear -= self.im2 * lin_impulse2;
mj_lambda2.angular -= self
.ii2_sqrt
.transform_vector(ang_impulse2 + self.r2.gcross(lin_impulse2));
/*
* Motor
*/
if self.motor_inv_lhs != 0.0 {
mj_lambda1.angular += self
.ii1_sqrt
.transform_vector(self.motor_axis1 * self.motor_impulse);
mj_lambda2.angular -= self
.ii2_sqrt
.transform_vector(self.motor_axis2 * self.motor_impulse);
}
mj_lambdas[self.mj_lambda1 as usize] = mj_lambda1;
mj_lambdas[self.mj_lambda2 as usize] = mj_lambda2;
}
fn solve_dofs(&mut self, mj_lambda1: &mut DeltaVel<Real>, mj_lambda2: &mut DeltaVel<Real>) {
let ang_vel1 = self.ii1_sqrt.transform_vector(mj_lambda1.angular);
let ang_vel2 = self.ii2_sqrt.transform_vector(mj_lambda2.angular);
let lin_dvel = (mj_lambda2.linear + ang_vel2.gcross(self.r2))
- (mj_lambda1.linear + ang_vel1.gcross(self.r1));
let ang_dvel = self.basis2.tr_mul(&ang_vel2) - self.basis1.tr_mul(&ang_vel1);
let rhs =
Vector5::new(lin_dvel.x, lin_dvel.y, lin_dvel.z, ang_dvel.x, ang_dvel.y) + self.rhs;
let impulse = self.inv_lhs * rhs;
self.impulse += impulse;
let lin_impulse1 = impulse.fixed_rows::<U3>(0).into_owned();
let lin_impulse2 = impulse.fixed_rows::<U3>(0).into_owned();
let ang_impulse1 = self.basis1 * impulse.fixed_rows::<U2>(3).into_owned();
let ang_impulse2 = self.basis2 * impulse.fixed_rows::<U2>(3).into_owned();
mj_lambda1.linear += self.im1 * lin_impulse1;
mj_lambda1.angular += self
.ii1_sqrt
.transform_vector(ang_impulse1 + self.r1.gcross(lin_impulse1));
mj_lambda2.linear -= self.im2 * lin_impulse2;
mj_lambda2.angular -= self
.ii2_sqrt
.transform_vector(ang_impulse2 + self.r2.gcross(lin_impulse2));
}
fn solve_motors(&mut self, mj_lambda1: &mut DeltaVel<Real>, mj_lambda2: &mut DeltaVel<Real>) {
if self.motor_inv_lhs != 0.0 {
let ang_vel1 = self.ii1_sqrt.transform_vector(mj_lambda1.angular);
let ang_vel2 = self.ii2_sqrt.transform_vector(mj_lambda2.angular);
let ang_dvel = ang_vel2.dot(&self.motor_axis2) - ang_vel1.dot(&self.motor_axis1);
let rhs = ang_dvel + self.motor_rhs;
let new_motor_impulse = na::clamp(
self.motor_impulse + self.motor_inv_lhs * rhs,
-self.motor_max_impulse,
self.motor_max_impulse,
);
let impulse = new_motor_impulse - self.motor_impulse;
self.motor_impulse = new_motor_impulse;
mj_lambda1.angular += self.ii1_sqrt.transform_vector(self.motor_axis1 * impulse);
mj_lambda2.angular -= self.ii2_sqrt.transform_vector(self.motor_axis2 * impulse);
}
}
pub fn solve(&mut self, mj_lambdas: &mut [DeltaVel<Real>]) {
let mut mj_lambda1 = mj_lambdas[self.mj_lambda1 as usize];
let mut mj_lambda2 = mj_lambdas[self.mj_lambda2 as usize];
self.solve_dofs(&mut mj_lambda1, &mut mj_lambda2);
self.solve_motors(&mut mj_lambda1, &mut mj_lambda2);
mj_lambdas[self.mj_lambda1 as usize] = mj_lambda1;
mj_lambdas[self.mj_lambda2 as usize] = mj_lambda2;
}
pub fn writeback_impulses(&self, joints_all: &mut [JointGraphEdge]) {
let joint = &mut joints_all[self.joint_id].weight;
if let JointParams::RevoluteJoint(revolute) = &mut joint.params {
revolute.impulse = self.impulse;
let rot_part = self.impulse.fixed_rows::<U2>(3).into_owned();
revolute.world_ang_impulse = self.basis1 * rot_part;
revolute.prev_axis1 = self.motor_axis1;
revolute.motor_last_angle = self.motor_angle;
revolute.motor_impulse = self.motor_impulse;
}
}
}
#[derive(Debug)]
pub(crate) struct RevoluteVelocityGroundConstraint {
mj_lambda2: usize,
joint_id: JointIndex,
r2: Vector<Real>,
inv_lhs: Matrix5<Real>,
rhs: Vector5<Real>,
impulse: Vector5<Real>,
motor_axis2: Vector<Real>,
motor_inv_lhs: Real,
motor_rhs: Real,
motor_impulse: Real,
motor_max_impulse: Real,
motor_angle: Real, // Exists just for writing it into the joint.
basis2: Matrix3x2<Real>,
im2: Real,
ii2_sqrt: AngularInertia<Real>,
}
impl RevoluteVelocityGroundConstraint {
pub fn from_params(
params: &IntegrationParameters,
joint_id: JointIndex,
rb1: &RigidBody,
rb2: &RigidBody,
joint: &RevoluteJoint,
flipped: bool,
) -> AnyJointVelocityConstraint {
let anchor2;
let anchor1;
let axis1;
let axis2;
let basis1;
let basis2;
if flipped {
axis1 = rb1.position * *joint.local_axis2;
axis2 = rb2.position * *joint.local_axis1;
anchor1 = rb1.position * joint.local_anchor2;
anchor2 = rb2.position * joint.local_anchor1;
basis1 = Matrix3x2::from_columns(&[
rb1.position * joint.basis2[0],
rb1.position * joint.basis2[1],
]);
basis2 = Matrix3x2::from_columns(&[
rb2.position * joint.basis1[0],
rb2.position * joint.basis1[1],
]);
} else {
axis1 = rb1.position * *joint.local_axis1;
axis2 = rb2.position * *joint.local_axis2;
anchor1 = rb1.position * joint.local_anchor1;
anchor2 = rb2.position * joint.local_anchor2;
basis1 = Matrix3x2::from_columns(&[
rb1.position * joint.basis1[0],
rb1.position * joint.basis1[1],
]);
basis2 = Matrix3x2::from_columns(&[
rb2.position * joint.basis2[0],
rb2.position * joint.basis2[1],
]);
};
let basis_projection2 = basis2 * basis2.transpose();
let basis2 = basis_projection2 * basis1;
let im2 = rb2.effective_inv_mass;
let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
let r1 = anchor1 - rb1.world_com;
let r2 = anchor2 - rb2.world_com;
let r2_mat = r2.gcross_matrix();
let mut lhs = Matrix5::zeros();
let lhs00 = ii2.quadform(&r2_mat).add_diagonal(im2);
let lhs10 = basis2.tr_mul(&(ii2 * r2_mat));
let lhs11 = ii2.quadform3x2(&basis2).into_matrix();
// Note that cholesky won't read the upper-right part
// of lhs so we don't have to fill it.
lhs.fixed_slice_mut::<U3, U3>(0, 0)
.copy_from(&lhs00.into_matrix());
lhs.fixed_slice_mut::<U2, U3>(3, 0).copy_from(&lhs10);
lhs.fixed_slice_mut::<U2, U2>(3, 3).copy_from(&lhs11);
let inv_lhs = Cholesky::new_unchecked(lhs).inverse();
let lin_rhs = (rb2.linvel + rb2.angvel.gcross(r2)) - (rb1.linvel + rb1.angvel.gcross(r1));
let ang_rhs = basis2.tr_mul(&rb2.angvel) - basis1.tr_mul(&rb1.angvel);
let rhs = Vector5::new(lin_rhs.x, lin_rhs.y, lin_rhs.z, ang_rhs.x, ang_rhs.y);
/*
* Motor part.
*/
let mut motor_rhs = 0.0;
let mut motor_inv_lhs = 0.0;
let mut motor_angle = 0.0;
let motor_max_impulse = joint.motor_max_impulse;
let (stiffness, damping, gamma, keep_lhs) = joint.motor_model.combine_coefficients(
params.dt,
joint.motor_stiffness,
joint.motor_damping,
);
if stiffness != 0.0 {
motor_angle = joint.estimate_motor_angle(&rb1.position, &rb2.position);
motor_rhs += (motor_angle - joint.motor_target_pos) * stiffness;
}
if damping != 0.0 {
let curr_vel = rb2.angvel.dot(&axis2) - rb1.angvel.dot(&axis1);
motor_rhs += (curr_vel - joint.motor_target_vel) * damping;
}
if stiffness != 0.0 || damping != 0.0 {
motor_inv_lhs = if keep_lhs {
crate::utils::inv(axis2.dot(&ii2.transform_vector(axis2))) * gamma
} else {
gamma
};
motor_rhs /= gamma;
}
let motor_impulse = na::clamp(joint.motor_impulse, -motor_max_impulse, motor_max_impulse)
* params.warmstart_coeff;
let result = RevoluteVelocityGroundConstraint {
joint_id,
mj_lambda2: rb2.active_set_offset,
im2,
ii2_sqrt: rb2.effective_world_inv_inertia_sqrt,
impulse: joint.impulse * params.warmstart_coeff,
basis2,
inv_lhs,
rhs,
r2,
motor_inv_lhs,
motor_impulse,
motor_axis2: axis2,
motor_max_impulse,
motor_rhs,
motor_angle,
};
AnyJointVelocityConstraint::RevoluteGroundConstraint(result)
}
pub fn warmstart(&self, mj_lambdas: &mut [DeltaVel<Real>]) {
let mut mj_lambda2 = mj_lambdas[self.mj_lambda2 as usize];
let lin_impulse = self.impulse.fixed_rows::<U3>(0).into_owned();
let ang_impulse = self.basis2 * self.impulse.fixed_rows::<U2>(3).into_owned();
mj_lambda2.linear -= self.im2 * lin_impulse;
mj_lambda2.angular -= self
.ii2_sqrt
.transform_vector(ang_impulse + self.r2.gcross(lin_impulse));
/*
* Motor
*/
if self.motor_inv_lhs != 0.0 {
mj_lambda2.angular -= self
.ii2_sqrt
.transform_vector(self.motor_axis2 * self.motor_impulse);
}
mj_lambdas[self.mj_lambda2 as usize] = mj_lambda2;
}
fn solve_dofs(&mut self, mj_lambda2: &mut DeltaVel<Real>) {
let ang_vel2 = self.ii2_sqrt.transform_vector(mj_lambda2.angular);
let lin_dvel = mj_lambda2.linear + ang_vel2.gcross(self.r2);
let ang_dvel = self.basis2.tr_mul(&ang_vel2);
let rhs =
Vector5::new(lin_dvel.x, lin_dvel.y, lin_dvel.z, ang_dvel.x, ang_dvel.y) + self.rhs;
let impulse = self.inv_lhs * rhs;
self.impulse += impulse;
let lin_impulse = impulse.fixed_rows::<U3>(0).into_owned();
let ang_impulse = self.basis2 * impulse.fixed_rows::<U2>(3).into_owned();
mj_lambda2.linear -= self.im2 * lin_impulse;
mj_lambda2.angular -= self
.ii2_sqrt
.transform_vector(ang_impulse + self.r2.gcross(lin_impulse));
}
fn solve_motors(&mut self, mj_lambda2: &mut DeltaVel<Real>) {
if self.motor_inv_lhs != 0.0 {
let ang_vel2 = self.ii2_sqrt.transform_vector(mj_lambda2.angular);
let ang_dvel = ang_vel2.dot(&self.motor_axis2);
let rhs = ang_dvel + self.motor_rhs;
let new_motor_impulse = na::clamp(
self.motor_impulse + self.motor_inv_lhs * rhs,
-self.motor_max_impulse,
self.motor_max_impulse,
);
let impulse = new_motor_impulse - self.motor_impulse;
self.motor_impulse = new_motor_impulse;
mj_lambda2.angular -= self.ii2_sqrt.transform_vector(self.motor_axis2 * impulse);
}
}
pub fn solve(&mut self, mj_lambdas: &mut [DeltaVel<Real>]) {
let mut mj_lambda2 = mj_lambdas[self.mj_lambda2 as usize];
self.solve_dofs(&mut mj_lambda2);
self.solve_motors(&mut mj_lambda2);
mj_lambdas[self.mj_lambda2 as usize] = mj_lambda2;
}
// FIXME: duplicated code with the non-ground constraint.
pub fn writeback_impulses(&self, joints_all: &mut [JointGraphEdge]) {
let joint = &mut joints_all[self.joint_id].weight;
if let JointParams::RevoluteJoint(revolute) = &mut joint.params {
revolute.impulse = self.impulse;
revolute.motor_impulse = self.motor_impulse;
revolute.motor_last_angle = self.motor_angle;
}
}
}