Bullet Collision Detection & Physics Library: btMultiBodyJointMotor.cpp Source File

Bullet Collision Detection & Physics Library

- Main Page
- Namespaces
- Classes
- Files

- File List
- File Members

btMultiBodyJointMotor.cpp
Go to the documentation of this file.
1/*
2Bullet Continuous Collision Detection and Physics Library
3Copyright (c) 2013 Erwin Coumans http://bulletphysics.org
4
5This software is provided 'as-is', without any express or implied warranty.
6In no event will the authors be held liable for any damages arising from the use of this software.
7Permission is granted to anyone to use this software for any purpose,
8including commercial applications, and to alter it and redistribute it freely,
9subject to the following restrictions:
10
111. 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.
122. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
133. This notice may not be removed or altered from any source distribution.
14*/
15
17
18#include "btMultiBodyJointMotor.h"
19#include "btMultiBody.h"
20#include "btMultiBodyLinkCollider.h"
21#include "BulletCollision/CollisionDispatch/btCollisionObject.h"
22
23btMultiBodyJointMotor::btMultiBodyJointMotor(btMultiBody* body, int link, btScalar desiredVelocity, btScalar maxMotorImpulse)
24 : btMultiBodyConstraint(body, body, link, body->getLink(link).m_parent, 1, true, MULTIBODY_CONSTRAINT_1DOF_JOINT_MOTOR),
25 m_desiredVelocity(desiredVelocity),
26 m_desiredPosition(0),
27 m_kd(1.),
28 m_kp(0),
29 m_erp(1),
30 m_rhsClamp(SIMD_INFINITY)
31{
32 m_maxAppliedImpulse = maxMotorImpulse;
33 // the data.m_jacobians never change, so may as well
34 // initialize them here
35}
36
37 void btMultiBodyJointMotor::finalizeMultiDof()
38{
39 allocateJacobiansMultiDof();
40 // note: we rely on the fact that data.m_jacobians are
41 // always initialized to zero by the Constraint ctor
42 int linkDoF = 0;
43 unsigned int offset = 6 + (m_bodyA->getLink(m_linkA).m_dofOffset + linkDoF);
44
45 // row 0: the lower bound
46 // row 0: the lower bound
47 jacobianA(0)[offset] = 1;
48
49 m_numDofsFinalized = m_jacSizeBoth;
50}
51
52 btMultiBodyJointMotor::btMultiBodyJointMotor(btMultiBody* body, int link, int linkDoF, btScalar desiredVelocity, btScalar maxMotorImpulse)
53 //:btMultiBodyConstraint(body,0,link,-1,1,true),
54 : btMultiBodyConstraint(body, body, link, body->getLink(link).m_parent, 1, true, MULTIBODY_CONSTRAINT_1DOF_JOINT_MOTOR),
55 m_desiredVelocity(desiredVelocity),
56 m_desiredPosition(0),
57 m_kd(1.),
58 m_kp(0),
59 m_erp(1),
60 m_rhsClamp(SIMD_INFINITY)
61{
62 btAssert(linkDoF < body->getLink(link).m_dofCount);
63
64 m_maxAppliedImpulse = maxMotorImpulse;
65}
66btMultiBodyJointMotor::~btMultiBodyJointMotor()
67{
68}
69
70 int btMultiBodyJointMotor::getIslandIdA() const
71{
72 if (this->m_linkA < 0)
73 {
74 btMultiBodyLinkCollider* col = m_bodyA->getBaseCollider();
75 if (col)
76 return col->getIslandTag();
77 }
78 else
79 {
80 if (m_bodyA->getLink(m_linkA).m_collider)
81 {
82 return m_bodyA->getLink(m_linkA).m_collider->getIslandTag();
83 }
84 }
85 return -1;
86}
87
88 int btMultiBodyJointMotor::getIslandIdB() const
89{
90 if (m_linkB < 0)
91 {
92 btMultiBodyLinkCollider* col = m_bodyB->getBaseCollider();
93 if (col)
94 return col->getIslandTag();
95 }
96 else
97 {
98 if (m_bodyB->getLink(m_linkB).m_collider)
99 {
100 return m_bodyB->getLink(m_linkB).m_collider->getIslandTag();
101 }
102 }
103 return -1;
104}
105
106 void btMultiBodyJointMotor::createConstraintRows(btMultiBodyConstraintArray& constraintRows,
107 btMultiBodyJacobianData& data,
108 const btContactSolverInfo& infoGlobal)
109{
110 // only positions need to be updated -- data.m_jacobians and force
111 // directions were set in the ctor and never change.
112
113 if (m_numDofsFinalized != m_jacSizeBoth)
114 {
115 finalizeMultiDof();
116 }
117
118 //don't crash
119 if (m_numDofsFinalized != m_jacSizeBoth)
120 return;
121
122 if (m_maxAppliedImpulse == 0.f)
123 return;
124
125 const btScalar posError = 0;
126 const btVector3 dummy(0, 0, 0);
127
128 for (int row = 0; row < getNumRows(); row++)
129 {
130 btMultiBodySolverConstraint& constraintRow = constraintRows.expandNonInitializing();
131
132 int dof = 0;
133 btScalar currentPosition = m_bodyA->getJointPosMultiDof(m_linkA)[dof];
134 btScalar currentVelocity = m_bodyA->getJointVelMultiDof(m_linkA)[dof];
135 btScalar positionStabiliationTerm = m_erp * (m_desiredPosition - currentPosition) / infoGlobal.m_timeStep;
136
137 btScalar velocityError = (m_desiredVelocity - currentVelocity);
138 btScalar rhs = m_kp * positionStabiliationTerm + currentVelocity + m_kd * velocityError;
139 if (rhs > m_rhsClamp)
140 {
141 rhs = m_rhsClamp;
142 }
143 if (rhs < -m_rhsClamp)
144 {
145 rhs = -m_rhsClamp;
146 }
147
148 fillMultiBodyConstraint(constraintRow, data, jacobianA(row), jacobianB(row), dummy, dummy, dummy, dummy, posError, infoGlobal, -m_maxAppliedImpulse, m_maxAppliedImpulse, false, 1, false, rhs);
149 constraintRow.m_orgConstraint = this;
150 constraintRow.m_orgDofIndex = row;
151 {
152 //expect either prismatic or revolute joint type for now
153 btAssert((m_bodyA->getLink(m_linkA).m_jointType == btMultibodyLink::eRevolute) || (m_bodyA->getLink(m_linkA).m_jointType == btMultibodyLink::ePrismatic));
154 switch (m_bodyA->getLink(m_linkA).m_jointType)
155 {
156 case btMultibodyLink::eRevolute:
157 {
158 constraintRow.m_contactNormal1.setZero();
159 constraintRow.m_contactNormal2.setZero();
160 btVector3 revoluteAxisInWorld = quatRotate(m_bodyA->getLink(m_linkA).m_cachedWorldTransform.getRotation(), m_bodyA->getLink(m_linkA).m_axes[0].m_topVec);
161 constraintRow.m_relpos1CrossNormal = revoluteAxisInWorld;
162 constraintRow.m_relpos2CrossNormal = -revoluteAxisInWorld;
163
164 break;
165 }
166 case btMultibodyLink::ePrismatic:
167 {
168 btVector3 prismaticAxisInWorld = quatRotate(m_bodyA->getLink(m_linkA).m_cachedWorldTransform.getRotation(), m_bodyA->getLink(m_linkA).m_axes[0].m_bottomVec);
169 constraintRow.m_contactNormal1 = prismaticAxisInWorld;
170 constraintRow.m_contactNormal2 = -prismaticAxisInWorld;
171 constraintRow.m_relpos1CrossNormal.setZero();
172 constraintRow.m_relpos2CrossNormal.setZero();
173
174 break;
175 }
176 default:
177 {
178 btAssert(0);
179 }
180 };
181 }
182 }
183}
btCollisionObject.h
MULTIBODY_CONSTRAINT_1DOF_JOINT_MOTOR
@ MULTIBODY_CONSTRAINT_1DOF_JOINT_MOTOR
Definition btMultiBodyConstraint.h:28
btMultiBodyJointMotor.h
btMultiBodyLinkCollider.h
btMultiBody.h
quatRotate
btVector3 quatRotate(const btQuaternion &rotation, const btVector3 &v)
Definition btQuaternion.h:926
btScalar
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition btScalar.h:314
SIMD_INFINITY
#define SIMD_INFINITY
Definition btScalar.h:544
btAssert
#define btAssert(x)
Definition btScalar.h:153
btAlignedObjectArray< btMultiBodySolverConstraint >
btAlignedObjectArray::expandNonInitializing
T & expandNonInitializing()
Definition btAlignedObjectArray.h:230
btCollisionObject::getIslandTag
int getIslandTag() const
Definition btCollisionObject.h:448
btMultiBodyConstraint
Definition btMultiBodyConstraint.h:57
btMultiBodyConstraint::m_bodyB
btMultiBody * m_bodyB
Definition btMultiBodyConstraint.h:60
btMultiBodyConstraint::jacobianA
btScalar * jacobianA(int row)
Definition btMultiBodyConstraint.h:181
btMultiBodyConstraint::m_maxAppliedImpulse
btScalar m_maxAppliedImpulse
Definition btMultiBodyConstraint.h:73
btMultiBodyConstraint::jacobianB
btScalar * jacobianB(int row)
Definition btMultiBodyConstraint.h:189
btMultiBodyConstraint::m_numDofsFinalized
int m_numDofsFinalized
Definition btMultiBodyConstraint.h:72
btMultiBodyConstraint::allocateJacobiansMultiDof
void allocateJacobiansMultiDof()
Definition btMultiBodyConstraint.cpp:35
btMultiBodyConstraint::fillMultiBodyConstraint
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)
Definition btMultiBodyConstraint.cpp:53
btMultiBodyConstraint::m_bodyA
btMultiBody * m_bodyA
Definition btMultiBodyConstraint.h:59
btMultiBodyConstraint::m_linkB
int m_linkB
Definition btMultiBodyConstraint.h:62
btMultiBodyConstraint::m_jacSizeBoth
int m_jacSizeBoth
Definition btMultiBodyConstraint.h:68
btMultiBodyConstraint::getNumRows
int getNumRows() const
Definition btMultiBodyConstraint.h:125
btMultiBodyConstraint::m_linkA
int m_linkA
Definition btMultiBodyConstraint.h:61
btMultiBodyJointMotor::m_rhsClamp
btScalar m_rhsClamp
Definition btMultiBodyJointMotor.h:32
btMultiBodyJointMotor::m_desiredVelocity
btScalar m_desiredVelocity
Definition btMultiBodyJointMotor.h:27
btMultiBodyJointMotor::getIslandIdB
virtual int getIslandIdB() const
Definition btMultiBodyJointMotor.cpp:88
btMultiBodyJointMotor::m_desiredPosition
btScalar m_desiredPosition
Definition btMultiBodyJointMotor.h:28
btMultiBodyJointMotor::finalizeMultiDof
virtual void finalizeMultiDof()
Definition btMultiBodyJointMotor.cpp:37
btMultiBodyJointMotor::~btMultiBodyJointMotor
virtual ~btMultiBodyJointMotor()
Definition btMultiBodyJointMotor.cpp:66
btMultiBodyJointMotor::btMultiBodyJointMotor
btMultiBodyJointMotor(btMultiBody *body, int link, btScalar desiredVelocity, btScalar maxMotorImpulse)
This file was written by Erwin Coumans.
Definition btMultiBodyJointMotor.cpp:23
btMultiBodyJointMotor::m_kp
btScalar m_kp
Definition btMultiBodyJointMotor.h:30
btMultiBodyJointMotor::m_erp
btScalar m_erp
Definition btMultiBodyJointMotor.h:31
btMultiBodyJointMotor::m_kd
btScalar m_kd
Definition btMultiBodyJointMotor.h:29
btMultiBodyJointMotor::createConstraintRows
virtual void createConstraintRows(btMultiBodyConstraintArray &constraintRows, btMultiBodyJacobianData &data, const btContactSolverInfo &infoGlobal)
Definition btMultiBodyJointMotor.cpp:106
btMultiBodyJointMotor::getIslandIdA
virtual int getIslandIdA() const
Definition btMultiBodyJointMotor.cpp:70
btMultiBodyLinkCollider
Definition btMultiBodyLinkCollider.h:33
btMultiBody
Definition btMultiBody.h:51
btMultiBody::getJointPosMultiDof
btScalar * getJointPosMultiDof(int i)
Definition btMultiBody.cpp:388
btMultiBody::getLink
const btMultibodyLink & getLink(int index) const
Definition btMultiBody.h:114
btMultiBody::getBaseCollider
const btMultiBodyLinkCollider * getBaseCollider() const
Definition btMultiBody.h:128
btMultiBody::getJointVelMultiDof
btScalar * getJointVelMultiDof(int i)
Definition btMultiBody.cpp:393
btTransform::getRotation
btQuaternion getRotation() const
Return a quaternion representing the rotation.
Definition btTransform.h:119
btVector3
btVector3 can be used to represent 3D points and vectors.
Definition btVector3.h:82
btVector3::setZero
void setZero()
Definition btVector3.h:671
btContactSolverInfoData::m_timeStep
btScalar m_timeStep
Definition btContactSolverInfo.h:42
btContactSolverInfo
Definition btContactSolverInfo.h:76
btMultiBodyJacobianData
Definition btMultiBodyConstraint.h:44
btMultiBodySolverConstraint
1D constraint along a normal axis between bodyA and bodyB. It can be combined to solve contact and fr...
Definition btMultiBodySolverConstraint.h:30
btMultiBodySolverConstraint::m_orgConstraint
btMultiBodyConstraint * m_orgConstraint
Definition btMultiBodySolverConstraint.h:78
btMultiBodySolverConstraint::m_relpos1CrossNormal
btVector3 m_relpos1CrossNormal
Definition btMultiBodySolverConstraint.h:42
btMultiBodySolverConstraint::m_contactNormal2
btVector3 m_contactNormal2
Definition btMultiBodySolverConstraint.h:45
btMultiBodySolverConstraint::m_orgDofIndex
int m_orgDofIndex
Definition btMultiBodySolverConstraint.h:79
btMultiBodySolverConstraint::m_contactNormal1
btVector3 m_contactNormal1
Definition btMultiBodySolverConstraint.h:43
btMultiBodySolverConstraint::m_relpos2CrossNormal
btVector3 m_relpos2CrossNormal
Definition btMultiBodySolverConstraint.h:44
btMultibodyLink::m_collider
class btMultiBodyLinkCollider * m_collider
Definition btMultiBodyLink.h:132
btMultibodyLink::m_jointType
eFeatherstoneJointType m_jointType
Definition btMultiBodyLink.h:137
btMultibodyLink::ePrismatic
@ ePrismatic
Definition btMultiBodyLink.h:73
btMultibodyLink::eRevolute
@ eRevolute
Definition btMultiBodyLink.h:72
btMultibodyLink::m_cachedWorldTransform
btTransform m_cachedWorldTransform
Definition btMultiBodyLink.h:141
btMultibodyLink::m_axes
btSpatialMotionVector m_axes[6]
Definition btMultiBodyLink.h:93
btSpatialMotionVector::m_bottomVec
btVector3 m_bottomVec
Definition btSpatialAlgebra.h:96
btSpatialMotionVector::m_topVec
btVector3 m_topVec
Definition btSpatialAlgebra.h:96