Bullet Collision Detection & Physics Library
btMultiBodySphericalJointMotor.cpp
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1 /*
2 Bullet Continuous Collision Detection and Physics Library
3 Copyright (c) 2018 Erwin Coumans http://bulletphysics.org
4 
5 This software is provided 'as-is', without any express or implied warranty.
6 In no event will the authors be held liable for any damages arising from the use of this software.
7 Permission is granted to anyone to use this software for any purpose,
8 including commercial applications, and to alter it and redistribute it freely,
9 subject to the following restrictions:
10 
11 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
12 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
13 3. This notice may not be removed or altered from any source distribution.
14 */
15 
17 
19 #include "btMultiBody.h"
24 
26  : btMultiBodyConstraint(body, body, link, body->getLink(link).m_parent, 3, true, MULTIBODY_CONSTRAINT_SPHERICAL_MOTOR),
27  m_desiredVelocity(0, 0, 0),
28  m_desiredPosition(0,0,0,1),
29  m_use_multi_dof_params(false),
30  m_kd(1., 1., 1.),
31  m_kp(0.2, 0.2, 0.2),
32  m_erp(1),
33  m_rhsClamp(SIMD_INFINITY),
34  m_maxAppliedImpulseMultiDof(maxMotorImpulse, maxMotorImpulse, maxMotorImpulse),
35  m_damping(1.0, 1.0, 1.0)
36 {
37 
38  m_maxAppliedImpulse = maxMotorImpulse;
39 }
40 
41 
43 {
45  // note: we rely on the fact that data.m_jacobians are
46  // always initialized to zero by the Constraint ctor
47  int linkDoF = 0;
48  unsigned int offset = 6 + (m_bodyA->getLink(m_linkA).m_dofOffset + linkDoF);
49 
50  // row 0: the lower bound
51  // row 0: the lower bound
52  jacobianA(0)[offset] = 1;
53 
55 }
56 
57 
59 {
60 }
61 
63 {
64  if (this->m_linkA < 0)
65  {
67  if (col)
68  return col->getIslandTag();
69  }
70  else
71  {
73  {
75  }
76  }
77  return -1;
78 }
79 
81 {
82  if (m_linkB < 0)
83  {
85  if (col)
86  return col->getIslandTag();
87  }
88  else
89  {
91  {
93  }
94  }
95  return -1;
96 }
97 
100  const btContactSolverInfo& infoGlobal)
101 {
102  // only positions need to be updated -- data.m_jacobians and force
103  // directions were set in the ctor and never change.
104 
106  {
108  }
109 
110  //don't crash
112  return;
113 
114 
115  if (m_maxAppliedImpulse == 0.f)
116  return;
117 
118  const btScalar posError = 0;
119  const btVector3 dummy(0, 0, 0);
120 
121 
122  btVector3 axis[3] = { btVector3(1, 0, 0), btVector3(0, 1, 0), btVector3(0, 0, 1) };
123 
124  btQuaternion desiredQuat = m_desiredPosition;
129 
130 btQuaternion relRot = currentQuat.inverse() * desiredQuat;
131  btVector3 angleDiff;
133 
134 
135 
136  for (int row = 0; row < getNumRows(); row++)
137  {
138  btMultiBodySolverConstraint& constraintRow = constraintRows.expandNonInitializing();
139 
140  int dof = row;
141 
142  btScalar currentVelocity = m_bodyA->getJointVelMultiDof(m_linkA)[dof];
143  btScalar desiredVelocity = this->m_desiredVelocity[row];
144 
145  double kd = m_use_multi_dof_params ? m_kd[row % 3] : m_kd[0];
146  btScalar velocityError = (desiredVelocity - currentVelocity) * kd;
147 
148  btMatrix3x3 frameAworld;
149  frameAworld.setIdentity();
150  frameAworld = m_bodyA->localFrameToWorld(m_linkA, frameAworld);
151  btScalar posError = 0;
152  {
155  {
157  {
158  btVector3 constraintNormalAng = frameAworld.getColumn(row % 3);
159  double kp = m_use_multi_dof_params ? m_kp[row % 3] : m_kp[0];
160  posError = kp*angleDiff[row % 3];
161  double max_applied_impulse = m_use_multi_dof_params ? m_maxAppliedImpulseMultiDof[row % 3] : m_maxAppliedImpulse;
162  fillMultiBodyConstraint(constraintRow, data, 0, 0, constraintNormalAng,
163  btVector3(0,0,0), dummy, dummy,
164  posError,
165  infoGlobal,
166  -max_applied_impulse, max_applied_impulse, true,
167  1.0, false, 0, 0,
168  m_damping[row % 3]);
169  constraintRow.m_orgConstraint = this;
170  constraintRow.m_orgDofIndex = row;
171  break;
172  }
173  default:
174  {
175  btAssert(0);
176  }
177  };
178  }
179  }
180 }
@ MULTIBODY_CONSTRAINT_SPHERICAL_MOTOR
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:314
#define SIMD_INFINITY
Definition: btScalar.h:544
#define btAssert(x)
Definition: btScalar.h:153
int getIslandTag() const
static bool matrixToEulerXYZ(const btMatrix3x3 &mat, btVector3 &xyz)
The btMatrix3x3 class implements a 3x3 rotation matrix, to perform linear algebra in combination with...
Definition: btMatrix3x3.h:50
void setIdentity()
Set the matrix to the identity.
Definition: btMatrix3x3.h:323
btVector3 getColumn(int i) const
Get a column of the matrix as a vector.
Definition: btMatrix3x3.h:142
btScalar * jacobianA(int row)
btScalar fillMultiBodyConstraint(btMultiBodySolverConstraint &solverConstraint, btMultiBodyJacobianData &data, btScalar *jacOrgA, btScalar *jacOrgB, const btVector3 &constraintNormalAng, const btVector3 &constraintNormalLin, const btVector3 &posAworld, const btVector3 &posBworld, btScalar posError, const btContactSolverInfo &infoGlobal, btScalar lowerLimit, btScalar upperLimit, bool angConstraint=false, btScalar relaxation=1.f, bool isFriction=false, btScalar desiredVelocity=0, btScalar cfmSlip=0, btScalar damping=1.0)
btMultiBodySphericalJointMotor(btMultiBody *body, int link, btScalar maxMotorImpulse)
This file was written by Erwin Coumans.
virtual void createConstraintRows(btMultiBodyConstraintArray &constraintRows, btMultiBodyJacobianData &data, const btContactSolverInfo &infoGlobal)
btMatrix3x3 localFrameToWorld(int i, const btMatrix3x3 &local_frame) const
btScalar * getJointPosMultiDof(int i)
const btMultibodyLink & getLink(int index) const
Definition: btMultiBody.h:114
const btMultiBodyLinkCollider * getBaseCollider() const
Definition: btMultiBody.h:128
btScalar * getJointVelMultiDof(int i)
The btQuaternion implements quaternion to perform linear algebra rotations in combination with btMatr...
Definition: btQuaternion.h:50
btQuaternion inverse() const
Return the inverse of this quaternion.
Definition: btQuaternion.h:497
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:82
1D constraint along a normal axis between bodyA and bodyB. It can be combined to solve contact and fr...
btMultiBodyConstraint * m_orgConstraint