1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154

use na::{self, DVectorSliceMut, Isometry3, RealField, Translation3, Unit, Vector3};

use crate::joint::{Joint, PrismaticJoint};
use crate::math::{JacobianSliceMut, Velocity};
use crate::object::{BodyPartHandle, Multibody, MultibodyLink};
use crate::solver::{ConstraintSet, GenericNonlinearConstraint, IntegrationParameters};

/// A joint that allows two translational degrees of freedom.
#[derive(Copy, Clone, Debug)]
pub struct RectangularJoint<N: RealField> {
    prism1: PrismaticJoint<N>,
    prism2: PrismaticJoint<N>,
}

impl<N: RealField> RectangularJoint<N> {
    /// Creates a new rectangular joint allowing relative translations anlon the two provided axii.Isometry3
    ///
    /// Both axii are expressed in the local coordinate frame on the attached multibody links.
    pub fn new(axis1: Unit<Vector3<N>>, axis2: Unit<Vector3<N>>, offset1: N, offset2: N) -> Self {
        RectangularJoint {
            prism1: PrismaticJoint::new(axis1, offset1),
            prism2: PrismaticJoint::new(axis2, offset2),
        }
    }
}

impl<N: RealField> Joint<N> for RectangularJoint<N> {
    #[inline]
    fn ndofs(&self) -> usize {
        2
    }

    fn body_to_parent(&self, parent_shift: &Vector3<N>, body_shift: &Vector3<N>) -> Isometry3<N> {
        let t = Translation3::from(parent_shift - body_shift)
            * self.prism1.translation()
            * self.prism2.translation();
        Isometry3::from_parts(t, na::one())
    }

    fn update_jacobians(&mut self, body_shift: &Vector3<N>, vels: &[N]) {
        self.prism1.update_jacobians(body_shift, vels);
        self.prism2.update_jacobians(body_shift, &[vels[1]]);
    }

    fn jacobian(&self, transform: &Isometry3<N>, out: &mut JacobianSliceMut<N>) {
        self.prism1.jacobian(transform, &mut out.columns_mut(0, 1));
        self.prism2.jacobian(transform, &mut out.columns_mut(1, 1));
    }

    fn jacobian_dot(&self, _: &Isometry3<N>, _: &mut JacobianSliceMut<N>) {}

    fn jacobian_dot_veldiff_mul_coordinates(
        &self,
        _: &Isometry3<N>,
        _: &[N],
        _: &mut JacobianSliceMut<N>,
    ) {
    }

    fn jacobian_mul_coordinates(&self, vels: &[N]) -> Velocity<N> {
        self.prism1.jacobian_mul_coordinates(vels)
            + self.prism2.jacobian_mul_coordinates(&[vels[1]])
    }

    fn jacobian_dot_mul_coordinates(&self, _: &[N]) -> Velocity<N> {
        Velocity::zero()
    }

    fn default_damping(&self, out: &mut DVectorSliceMut<N>) {
        self.prism1.default_damping(&mut out.rows_mut(0, 1));
        self.prism2.default_damping(&mut out.rows_mut(1, 1));
    }

    fn integrate(&mut self, parameters: &IntegrationParameters<N>, vels: &[N]) {
        self.prism1.integrate(parameters, vels);
        self.prism2.integrate(parameters, &[vels[1]]);
    }

    fn apply_displacement(&mut self, disp: &[N]) {
        self.prism1.apply_displacement(disp);
        self.prism2.apply_displacement(&[disp[1]]);
    }

    #[inline]
    fn clone(&self) -> Box<dyn Joint<N>> {
        Box::new(*self)
    }

    fn num_velocity_constraints(&self) -> usize {
        self.prism1.num_velocity_constraints() + self.prism2.num_velocity_constraints()
    }

    fn velocity_constraints(
        &self,
        parameters: &IntegrationParameters<N>,
        multibody: &Multibody<N>,
        link: &MultibodyLink<N>,
        assembly_id: usize,
        dof_id: usize,
        ext_vels: &[N],
        ground_j_id: &mut usize,
        jacobians: &mut [N],
        constraints: &mut ConstraintSet<N, (), (), usize>,
    ) {
        self.prism1.velocity_constraints(
            parameters,
            multibody,
            link,
            assembly_id,
            dof_id,
            ext_vels,
            ground_j_id,
            jacobians,
            constraints,
        );
        self.prism2.velocity_constraints(
            parameters,
            multibody,
            link,
            assembly_id,
            dof_id + 1,
            ext_vels,
            ground_j_id,
            jacobians,
            constraints,
        );
    }

    fn num_position_constraints(&self) -> usize {
        // NOTE: we don't test if constraints exist to simplify indexing.
        2
    }

    fn position_constraint(
        &self,
        i: usize,
        multibody: &Multibody<N>,
        link: &MultibodyLink<N>,
        handle: BodyPartHandle<()>,
        dof_id: usize,
        jacobians: &mut [N],
    ) -> Option<GenericNonlinearConstraint<N, ()>> {
        if i == 0 {
            self.prism1
                .position_constraint(0, multibody, link, handle, dof_id, jacobians)
        } else {
            self.prism2
                .position_constraint(0, multibody, link, handle, dof_id + 1, jacobians)
        }
    }
}

prismatic_motor_limit_methods_1!(RectangularJoint, prism1);
prismatic_motor_limit_methods_2!(RectangularJoint, prism2);