-
Notifications
You must be signed in to change notification settings - Fork 485
/
ODEJoint.cc
1231 lines (1098 loc) · 36.1 KB
/
ODEJoint.cc
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
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Copyright (C) 2012 Open Source Robotics Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include <boost/bind/bind.hpp>
#include "gazebo/common/Exception.hh"
#include "gazebo/common/Console.hh"
#include "gazebo/common/Assert.hh"
#include "gazebo/physics/World.hh"
#include "gazebo/physics/Link.hh"
#include "gazebo/physics/PhysicsEngine.hh"
#include "gazebo/physics/ode/ODELink.hh"
#include "gazebo/physics/ode/ODEJoint.hh"
#include "gazebo/physics/GearboxJoint.hh"
#include "gazebo/physics/ScrewJoint.hh"
#include "gazebo/physics/JointWrench.hh"
// Needed for fixing issue 2430
#include "gazebo/physics/ode/ODEHingeJoint.hh"
using namespace gazebo;
using namespace physics;
//////////////////////////////////////////////////
ODEJoint::ODEJoint(BasePtr _parent)
: Joint(_parent)
{
this->jointId = nullptr;
this->implicitDampingState[0] = ODEJoint::NONE;
this->implicitDampingState[1] = ODEJoint::NONE;
this->stiffnessDampingInitialized = false;
this->feedback = nullptr;
this->currentKd[0] = 0;
this->currentKd[1] = 0;
this->currentKp[0] = 0;
this->currentKp[1] = 0;
this->forceApplied[0] = 0;
this->forceApplied[1] = 0;
this->useImplicitSpringDamper = false;
this->stopERP = 0.0;
this->stopCFM = 0.0;
this->angleOffset[0] = 0.0;
this->angleOffset[1] = 0.0;
}
//////////////////////////////////////////////////
ODEJoint::~ODEJoint()
{
this->Fini();
}
//////////////////////////////////////////////////
void ODEJoint::Fini()
{
this->applyDamping.reset();
if (this->feedback)
delete this->feedback;
this->feedback = nullptr;
this->Detach();
if (this->jointId)
dJointDestroy(this->jointId);
this->jointId = nullptr;
Joint::Fini();
}
//////////////////////////////////////////////////
void ODEJoint::Load(sdf::ElementPtr _sdf)
{
Joint::Load(_sdf);
if (this->sdf->HasElement("physics") &&
this->sdf->GetElement("physics")->HasElement("ode"))
{
sdf::ElementPtr elem = this->sdf->GetElement("physics")->GetElement("ode");
if (elem->HasElement("implicit_spring_damper"))
{
this->useImplicitSpringDamper = elem->Get<bool>("implicit_spring_damper");
}
// initializa both axis, \todo: make cfm, erp per axis
this->stopERP = elem->GetElement("limit")->Get<double>("erp");
for (unsigned int i = 0; i < this->DOF(); ++i)
this->SetParam("stop_erp", i, this->stopERP);
// initializa both axis, \todo: make cfm, erp per axis
this->stopCFM = elem->GetElement("limit")->Get<double>("cfm");
for (unsigned int i = 0; i < this->DOF(); ++i)
this->SetParam("stop_cfm", i, this->stopCFM);
if (elem->HasElement("suspension"))
{
this->SetParam(dParamSuspensionERP,
elem->GetElement("suspension")->Get<double>("erp"));
this->SetParam(dParamSuspensionCFM,
elem->GetElement("suspension")->Get<double>("cfm"));
}
if (elem->HasElement("fudge_factor"))
this->SetParam(dParamFudgeFactor,
elem->GetElement("fudge_factor")->Get<double>());
if (elem->HasElement("cfm"))
this->SetParam("cfm", 0, elem->Get<double>("cfm"));
if (elem->HasElement("erp"))
this->SetParam("erp", 0, elem->Get<double>("erp"));
if (elem->HasElement("bounce"))
this->SetParam(dParamBounce,
elem->GetElement("bounce")->Get<double>());
if (elem->HasElement("max_force"))
this->SetParam(dParamFMax,
elem->GetElement("max_force")->Get<double>());
if (elem->HasElement("velocity"))
this->SetParam(dParamVel,
elem->GetElement("velocity")->Get<double>());
}
}
//////////////////////////////////////////////////
LinkPtr ODEJoint::GetJointLink(unsigned int _index) const
{
LinkPtr result;
if (!this->jointId)
{
gzerr << "ODE Joint ID is invalid\n";
return result;
}
if (_index == 0 || _index == 1)
{
ODELinkPtr odeLink1 = boost::static_pointer_cast<ODELink>(this->childLink);
ODELinkPtr odeLink2 = boost::static_pointer_cast<ODELink>(this->parentLink);
if (odeLink1 != nullptr &&
dJointGetBody(this->jointId, _index) == odeLink1->GetODEId())
result = this->childLink;
else if (odeLink2)
result = this->parentLink;
}
return result;
}
//////////////////////////////////////////////////
bool ODEJoint::AreConnected(LinkPtr _one, LinkPtr _two) const
{
ODELinkPtr odeLink1 = boost::dynamic_pointer_cast<ODELink>(_one);
ODELinkPtr odeLink2 = boost::dynamic_pointer_cast<ODELink>(_two);
if (odeLink1 == nullptr || odeLink2 == nullptr)
gzthrow("ODEJoint requires ODE bodies\n");
return dAreConnected(odeLink1->GetODEId(), odeLink2->GetODEId());
}
//////////////////////////////////////////////////
// child classes where appropriate
double ODEJoint::GetParam(unsigned int /*parameter*/) const
{
return 0;
}
//////////////////////////////////////////////////
void ODEJoint::Attach(LinkPtr _parent, LinkPtr _child)
{
Joint::Attach(_parent, _child);
ODELinkPtr odechild = boost::dynamic_pointer_cast<ODELink>(this->childLink);
ODELinkPtr odeparent = boost::dynamic_pointer_cast<ODELink>(this->parentLink);
if (odechild == nullptr && odeparent == nullptr)
gzthrow("ODEJoint requires at least one ODE link\n");
if (!this->jointId)
gzerr << "ODE Joint ID is invalid\n";
if (this->HasType(Base::HINGE2_JOINT) &&
(odechild == nullptr || odeparent == nullptr))
gzthrow("ODEHinge2Joint cannot be connected to the world");
if (!odechild && odeparent)
{
dJointAttach(this->jointId, 0, odeparent->GetODEId());
}
else if (odechild && !odeparent)
{
dJointAttach(this->jointId, odechild->GetODEId(), 0);
}
else if (odechild && odeparent)
{
if (this->HasType(Base::HINGE2_JOINT))
dJointAttach(this->jointId, odeparent->GetODEId(), odechild->GetODEId());
else
dJointAttach(this->jointId, odechild->GetODEId(), odeparent->GetODEId());
}
}
//////////////////////////////////////////////////
void ODEJoint::Detach()
{
auto odeChild = boost::dynamic_pointer_cast<ODELink>(this->childLink);
auto odeParent = boost::dynamic_pointer_cast<ODELink>(this->parentLink);
Joint::Detach();
this->childLink.reset();
this->parentLink.reset();
// By the time we get here, links and ODEIds might have already been
// cleaned up
if ((odeParent == nullptr || odeParent->GetODEId() == nullptr) ||
(odeChild == nullptr || odeChild->GetODEId() == nullptr))
{
return;
}
if (this->jointId)
dJointAttach(this->jointId, 0, 0);
else
gzerr << "ODE Joint ID is invalid\n";
}
//////////////////////////////////////////////////
// where appropriate
void ODEJoint::SetParam(unsigned int /*parameter*/, double /*value*/)
{
if (this->childLink)
this->childLink->SetEnabled(true);
if (this->parentLink)
this->parentLink->SetEnabled(true);
}
//////////////////////////////////////////////////
void ODEJoint::SetERP(double _newERP)
{
this->SetParam(dParamSuspensionERP, _newERP);
}
//////////////////////////////////////////////////
double ODEJoint::GetERP()
{
return this->GetParam(dParamSuspensionERP);
}
//////////////////////////////////////////////////
void ODEJoint::SetCFM(double _newCFM)
{
this->SetParam(dParamSuspensionCFM, _newCFM);
}
//////////////////////////////////////////////////
double ODEJoint::GetCFM()
{
return this->GetParam(dParamSuspensionCFM);
}
//////////////////////////////////////////////////
dJointFeedback *ODEJoint::GetFeedback()
{
if (this->jointId)
return dJointGetFeedback(this->jointId);
else
gzerr << "ODE Joint ID is invalid\n";
return nullptr;
}
//////////////////////////////////////////////////
void ODEJoint::SetUpperLimit(const unsigned int _index, const double _limit)
{
Joint::SetUpperLimit(_index, _limit);
switch (_index)
{
case 0:
this->SetParam(dParamHiStop, _limit);
break;
case 1:
this->SetParam(dParamHiStop2, _limit);
break;
case 2:
this->SetParam(dParamHiStop3, _limit);
break;
default:
gzerr << "Invalid index[" << _index << "]\n";
};
}
//////////////////////////////////////////////////
void ODEJoint::SetLowerLimit(const unsigned int _index, const double _limit)
{
Joint::SetLowerLimit(_index, _limit);
switch (_index)
{
case 0:
this->SetParam(dParamLoStop, _limit);
break;
case 1:
this->SetParam(dParamLoStop2, _limit);
break;
case 2:
this->SetParam(dParamLoStop3, _limit);
break;
default:
gzerr << "Invalid index[" << _index << "]\n";
};
}
//////////////////////////////////////////////////
ignition::math::Vector3d ODEJoint::LinkForce(
const unsigned int _index) const
{
ignition::math::Vector3d result;
if (!this->jointId)
{
gzerr << "ODE Joint ID is invalid\n";
return result;
}
dJointFeedback *jointFeedback = dJointGetFeedback(this->jointId);
if (_index == 0)
result.Set(jointFeedback->f1[0], jointFeedback->f1[1],
jointFeedback->f1[2]);
else
result.Set(jointFeedback->f2[0], jointFeedback->f2[1],
jointFeedback->f2[2]);
return result;
}
//////////////////////////////////////////////////
ignition::math::Vector3d ODEJoint::LinkTorque(
const unsigned int _index) const
{
ignition::math::Vector3d result;
if (!this->jointId)
{
gzerr << "ODE Joint ID is invalid\n";
return result;
}
dJointFeedback *jointFeedback = dJointGetFeedback(this->jointId);
if (!jointFeedback)
{
gzerr << "Joint feedback uninitialized" << std::endl;
return result;
}
if (_index == 0)
result.Set(jointFeedback->t1[0], jointFeedback->t1[1],
jointFeedback->t1[2]);
else
result.Set(jointFeedback->t2[0], jointFeedback->t2[1],
jointFeedback->t2[2]);
return result;
}
//////////////////////////////////////////////////
void ODEJoint::SetAxis(const unsigned int _index,
const ignition::math::Vector3d &_axis)
{
}
//////////////////////////////////////////////////
bool ODEJoint::SetParam(const std::string &_key, unsigned int _index,
const boost::any &_value)
{
// Axis parameters for multi-axis joints use a group bitmask
// to identify the variable.
unsigned int group;
switch (_index)
{
case 0:
group = dParamGroup1;
break;
case 1:
group = dParamGroup2;
break;
case 2:
group = dParamGroup3;
break;
default:
gzerr << "Invalid index[" << _index << "]\n";
return false;
};
// try because boost::any_cast can throw
try
{
if (_key == "fudge_factor")
{
this->SetParam(dParamFudgeFactor, boost::any_cast<double>(_value));
}
else if (_key == "suspension_erp")
{
this->SetParam(dParamSuspensionERP, boost::any_cast<double>(_value));
}
else if (_key == "suspension_cfm")
{
this->SetParam(dParamSuspensionCFM, boost::any_cast<double>(_value));
}
else if (_key == "stop_erp")
{
this->SetParam(dParamStopERP | group, boost::any_cast<double>(_value));
}
else if (_key == "stop_cfm")
{
this->SetParam(dParamStopCFM | group, boost::any_cast<double>(_value));
}
else if (_key == "erp")
{
this->SetParam(dParamERP, boost::any_cast<double>(_value));
}
else if (_key == "cfm")
{
this->SetParam(dParamCFM, boost::any_cast<double>(_value));
}
else if (_key == "fmax")
{
this->SetParam(dParamFMax | group, boost::any_cast<double>(_value));
}
else if (_key == "friction")
{
// To represent Coulomb friction,
// set FMax to friction value
// set Vel to 0
this->SetParam(group | dParamFMax, boost::any_cast<double>(_value));
this->SetParam(group | dParamVel, 0.0);
}
else if (_key == "vel")
{
this->SetParam(dParamVel | group, boost::any_cast<double>(_value));
}
else if (_key == "hi_stop")
{
this->SetParam(dParamHiStop | group, boost::any_cast<double>(_value));
}
else if (_key == "lo_stop")
{
this->SetParam(dParamLoStop | group, boost::any_cast<double>(_value));
}
else if (_key == "thread_pitch")
{
ScrewJoint<ODEJoint>* screwJoint =
dynamic_cast<ScrewJoint<ODEJoint>* >(this);
if (screwJoint != nullptr)
{
screwJoint->SetThreadPitch(boost::any_cast<double>(_value));
}
else
{
gzerr << "Trying to set " << _key << " for non-screw joints."
<< std::endl;
return 0;
}
}
else if (_key == "gearbox_ratio")
{
GearboxJoint<ODEJoint>* gearboxJoint =
dynamic_cast<GearboxJoint<ODEJoint>* >(this);
if (gearboxJoint != nullptr)
{
gearboxJoint->SetGearboxRatio(boost::any_cast<double>(_value));
}
else
{
gzerr << "Trying to set " << _key << " for non-gearbox joints."
<< std::endl;
return 0;
}
}
else
{
gzerr << "Unable to handle joint attribute[" << _key << "]\n";
return false;
}
}
catch(const boost::bad_any_cast &e)
{
gzerr << "SetParam(" << _key << ")"
<< " boost any_cast error:" << e.what()
<< std::endl;
return false;
}
return true;
}
//////////////////////////////////////////////////
double ODEJoint::GetParam(const std::string &_key, unsigned int _index)
{
// Axis parameters for multi-axis joints use a group bitmask
// to identify the variable.
unsigned int group;
switch (_index)
{
case 0:
group = dParamGroup1;
break;
case 1:
group = dParamGroup2;
break;
case 2:
group = dParamGroup3;
break;
default:
gzerr << "Invalid index[" << _index << "]\n";
return false;
}
try
{
if (_key == "fudge_factor")
{
return this->GetParam(dParamFudgeFactor);
}
else if (_key == "suspension_erp")
{
return this->GetParam(dParamSuspensionERP);
}
else if (_key == "suspension_cfm")
{
return this->GetParam(dParamSuspensionCFM);
}
else if (_key == "stop_erp")
{
return this->GetParam(dParamStopERP | group);
}
else if (_key == "stop_cfm")
{
return this->GetParam(dParamStopCFM | group);
}
else if (_key == "erp")
{
return this->GetParam(dParamERP);
}
else if (_key == "cfm")
{
return this->GetParam(dParamCFM);
}
else if (_key == "fmax")
{
return this->GetParam(dParamFMax | group);
}
else if (_key == "friction")
{
return this->GetParam(dParamFMax | group);
}
else if (_key == "vel")
{
return this->GetParam(dParamVel | group);
}
else if (_key == "hi_stop")
{
return this->GetParam(dParamHiStop | group);
}
else if (_key == "lo_stop")
{
return this->GetParam(dParamLoStop | group);
}
else if (_key == "thread_pitch")
{
ScrewJoint<ODEJoint>* screwJoint =
dynamic_cast<ScrewJoint<ODEJoint>* >(this);
if (screwJoint != nullptr)
{
return screwJoint->GetThreadPitch();
}
else
{
gzerr << "Trying to get " << _key << " for non-screw joints."
<< std::endl;
return 0;
}
}
else if (_key == "gearbox_ratio")
{
GearboxJoint<ODEJoint>* gearboxJoint =
dynamic_cast<GearboxJoint<ODEJoint>* >(this);
if (gearboxJoint != nullptr)
{
return gearboxJoint->GetGearboxRatio();
}
else
{
gzerr << "Trying to get " << _key << " for non-gearbox joints."
<< std::endl;
return 0;
}
}
}
catch(common::Exception &e)
{
gzerr << "GetParam(" << _key << ") error:"
<< e.GetErrorStr()
<< std::endl;
return 0;
}
gzerr << "Unable to get joint attribute[" << _key << "]"
<< std::endl;
return 0;
}
//////////////////////////////////////////////////
void ODEJoint::Reset()
{
if (this->jointId)
dJointReset(this->jointId);
else
gzerr << "ODE Joint ID is invalid\n";
this->forceAppliedTime = common::Time::Zero;
Joint::Reset();
}
//////////////////////////////////////////////////
void ODEJoint::CacheForceTorque()
{
// Does nothing for now, will add when recovering pull request #1721
}
//////////////////////////////////////////////////
JointWrench ODEJoint::GetForceTorque(unsigned int /*_index*/)
{
// Note that:
// f2, t2 are the force torque measured on parent body's cg
// f1, t1 are the force torque measured on child body's cg
dJointFeedback *fb = this->GetFeedback();
if (fb)
{
// kind of backwards here, body1 (parent) corresponds go f2, t2
// and body2 (child) corresponds go f1, t1
this->wrench.body2Force.Set(fb->f1[0], fb->f1[1], fb->f1[2]);
this->wrench.body2Torque.Set(fb->t1[0], fb->t1[1], fb->t1[2]);
this->wrench.body1Force.Set(fb->f2[0], fb->f2[1], fb->f2[2]);
this->wrench.body1Torque.Set(fb->t2[0], fb->t2[1], fb->t2[2]);
// get force applied through SetForce
physics::JointWrench wrenchAppliedWorld;
if (this->HasType(physics::Base::HINGE_JOINT))
{
// rotate force into child link frame
// LocalAxis is the axis specified in parent link frame!!!
wrenchAppliedWorld.body2Torque =
this->GetForce(0u) * this->LocalAxis(0u);
// gzerr << "body2Torque [" << wrenchAppliedWorld.body2Torque
// << "] axis [" << this->LocalAxis(0u)
// << "]\n";
wrenchAppliedWorld.body1Torque = -wrenchAppliedWorld.body2Torque;
}
else if (this->HasType(physics::Base::SLIDER_JOINT))
{
// rotate force into child link frame
wrenchAppliedWorld.body2Force =
this->GetForce(0u) * this->LocalAxis(0u);
wrenchAppliedWorld.body1Force = -wrenchAppliedWorld.body2Force;
}
else if (this->HasType(physics::Base::FIXED_JOINT))
{
// no correction are necessary for fixed joint
}
else
{
/// \TODO: fix for multi-axis joints
gzerr << "force torque for joint type [" << this->GetType()
<< "] not implemented, returns false results!!\n";
}
// convert wrench from child cg location to child link frame
if (this->childLink)
{
ignition::math::Pose3d childPose = this->childLink->WorldPose();
// convert torque from about child CG to joint anchor location
// cg position specified in child link frame
ignition::math::Pose3d cgPose;
auto inertial = this->childLink->GetInertial();
if (inertial)
cgPose = inertial->Pose();
// anchorPose location of joint in child frame
// childMomentArm: from child CG to joint location in child link frame
// moment arm rotated into world frame (given feedback is in world frame)
ignition::math::Vector3d childMomentArm = childPose.Rot().RotateVector(
(this->anchorPose -
ignition::math::Pose3d(cgPose.Pos(),
ignition::math::Quaterniond::Identity)).Pos());
// gzerr << "anchor [" << anchorPose
// << "] iarm[" << this->childLink->GetInertial()->GetPose().Pos()
// << "] childMomentArm[" << childMomentArm
// << "] f1[" << this->wrench.body2Force
// << "] t1[" << this->wrench.body2Torque
// << "] fxp[" << this->wrench.body2Force.Cross(childMomentArm)
// << "]\n";
this->wrench.body2Torque += this->wrench.body2Force.Cross(childMomentArm);
// rotate resulting body2Force in world frame into link frame
this->wrench.body2Force = childPose.Rot().RotateVectorReverse(
-this->wrench.body2Force);
// rotate resulting body2Torque in world frame into link frame
this->wrench.body2Torque = childPose.Rot().RotateVectorReverse(
-this->wrench.body2Torque);
}
// convert torque from about parent CG to joint anchor location
if (this->parentLink)
{
// get child pose, or it's the inertial world if childLink is nullptr
ignition::math::Pose3d childPose;
if (this->childLink)
childPose = this->childLink->WorldPose();
else
gzerr << "missing child link, double check model.";
ignition::math::Pose3d parentPose = this->parentLink->WorldPose();
// if parent link exists, convert torque from about parent
// CG to joint anchor location
// parent cg specified in parent link frame
ignition::math::Pose3d cgPose;
auto inertial = this->parentLink->GetInertial();
if (inertial)
cgPose = inertial->Pose();
// get parent CG pose in child link frame
ignition::math::Pose3d parentCGInChildLink =
ignition::math::Pose3d(cgPose.Pos(),
ignition::math::Quaterniond::Identity) - (childPose - parentPose);
// paretnCGFrame in world frame
ignition::math::Pose3d parentCGInWorld = cgPose + parentPose;
// rotate momeent arms into world frame
ignition::math::Vector3d parentMomentArm =
parentCGInWorld.Rot().RotateVector(
(this->anchorPose - parentCGInChildLink).Pos());
// gzerr << "anchor [" << this->anchorPose
// << "] pcginc[" << parentCGInChildLink
// << "] iarm[" << cgPose
// << "] anc2pcg[" << this->anchorPose - parentCGInChildLink
// << "] parentMomentArm[" << parentMomentArm
// << "] f1[" << this->wrench.body1Force
// << "] t1[" << this->wrench.body1Torque
// << "] fxp[" << this->wrench.body1Force.Cross(parentMomentArm)
// << "]\n";
this->wrench.body1Torque +=
this->wrench.body1Force.Cross(parentMomentArm);
// rotate resulting body1Force in world frame into link frame
this->wrench.body1Force = parentPose.Rot().RotateVectorReverse(
-this->wrench.body1Force);
// rotate resulting body1Torque in world frame into link frame
this->wrench.body1Torque = parentPose.Rot().RotateVectorReverse(
-this->wrench.body1Torque);
if (!this->childLink)
{
gzlog << "Joint [" << this->GetScopedName()
<< "] with parent Link [" << this->parentLink->GetScopedName()
<< "] but no child Link. Child Link must be world.\n";
// if child link does not exist, use equal and opposite
this->wrench.body2Force = -this->wrench.body1Force;
this->wrench.body2Torque = -this->wrench.body1Torque;
// force/torque are in parent link frame, transform them into
// child link(world) frame.
auto parentToWorldTransform = this->parentLink->WorldPose();
this->wrench.body1Force =
parentToWorldTransform.Rot().RotateVector(
this->wrench.body1Force);
this->wrench.body1Torque =
parentToWorldTransform.Rot().RotateVector(
this->wrench.body1Torque);
}
}
else
{
if (!this->childLink)
{
gzerr << "Both parent and child links are invalid, abort.\n";
return JointWrench();
}
else
{
gzlog << "Joint [" << this->GetScopedName()
<< "] with child Link [" << this->childLink->GetScopedName()
<< "] but no parent Link. Parent Link must be world.\n";
// if parentLink does not exist, use equal opposite body1 wrench
this->wrench.body1Force = -this->wrench.body2Force;
this->wrench.body1Torque = -this->wrench.body2Torque;
// force/torque are in child link frame, transform them into
// parent link frame. Here, parent link is world, so zero transform.
auto childToWorldTransform = this->childLink->WorldPose();
this->wrench.body1Force =
childToWorldTransform.Rot().RotateVector(
this->wrench.body1Force);
this->wrench.body1Torque =
childToWorldTransform.Rot().RotateVector(
this->wrench.body1Torque);
}
}
this->wrench = this->wrench - wrenchAppliedWorld;
}
else
{
// forgot to set provide_feedback?
gzwarn << "GetForceTorque: forgot to set <provide_feedback>?\n";
}
return this->wrench;
}
//////////////////////////////////////////////////
bool ODEJoint::UsesImplicitSpringDamper()
{
return this->useImplicitSpringDamper;
}
//////////////////////////////////////////////////
void ODEJoint::UseImplicitSpringDamper(const bool _implicit)
{
this->useImplicitSpringDamper = _implicit;
}
//////////////////////////////////////////////////
void ODEJoint::ApplyImplicitStiffnessDamping()
{
// check if we are violating joint limits
if (this->DOF() > 2)
{
gzerr << "Incompatible joint type, DOF() = "
<< this->DOF() << " > 2\n";
return;
}
double dt = this->GetWorld()->Physics()->GetMaxStepSize();
for (unsigned int i = 0; i < this->DOF(); ++i)
{
double angle = this->Position(i);
double dAngle = 2.0 * this->GetVelocity(i) * dt;
angle += dAngle;
if ((ignition::math::equal(this->dissipationCoefficient[i], 0.0) &&
ignition::math::equal(this->stiffnessCoefficient[i], 0.0)) ||
angle >= this->upperLimit[i] ||
angle <= this->lowerLimit[i])
{
if (this->implicitDampingState[i] != ODEJoint::JOINT_LIMIT)
{
// We have hit the actual joint limit!
// turn off simulated damping by recovering cfm and erp,
// and recover joint limits
this->SetParam("stop_erp", i, this->stopERP);
this->SetParam("stop_cfm", i, this->stopCFM);
this->SetParam("hi_stop", i, this->upperLimit[i]);
this->SetParam("lo_stop", i, this->lowerLimit[i]);
this->SetParam("hi_stop", i, this->upperLimit[i]);
this->implicitDampingState[i] = ODEJoint::JOINT_LIMIT;
}
/* test to see if we can reduce jitter at joint limits
// apply spring damper explicitly if in joint limit
// this limits oscillations if spring is pushing joint
// into the limit.
{
double dampingForce = -fabs(this->dissipationCoefficient[i])
* this->GetVelocity(i);
double springForce = this->stiffnessCoefficient[i]
* (this->springReferencePosition[i] - this->Position(i));
this->SetForceImpl(i, dampingForce + springForce);
}
*/
}
else if (!ignition::math::equal(this->dissipationCoefficient[i], 0.0) ||
!ignition::math::equal(this->stiffnessCoefficient[i], 0.0))
{
double kd = fabs(this->dissipationCoefficient[i]);
double kp = this->stiffnessCoefficient[i];
/// \TODO: This bit of code involving adaptive damping
/// might be too complicated, add some more comments or simplify it.
if (this->dissipationCoefficient[i] < 0)
kd = this->ApplyAdaptiveDamping(i, kd);
// update if going into DAMPING_ACTIVE mode, or
// if current applied damping value is not the same as predicted.
if (this->implicitDampingState[i] != ODEJoint::DAMPING_ACTIVE ||
!ignition::math::equal(kd, this->currentKd[i]) ||
!ignition::math::equal(kp, this->currentKp[i]))
{
// save kp, kd applied for efficiency
this->currentKd[i] = kd;
this->currentKp[i] = kp;
// convert kp, kd to cfm, erp
double erp, cfm;
this->KpKdToCFMERP(dt, kp, kd, cfm, erp);
// add additional constraint row by fake hitting joint limit
// then, set erp and cfm to simulate viscous joint damping
this->SetParam("stop_erp", i, erp);
this->SetParam("stop_cfm", i, cfm);
this->SetParam("hi_stop", i, this->springReferencePosition[i]);
this->SetParam("lo_stop", i, this->springReferencePosition[i]);
this->SetParam("hi_stop", i, this->springReferencePosition[i]);
this->implicitDampingState[i] = ODEJoint::DAMPING_ACTIVE;
}
}
}
}
//////////////////////////////////////////////////
double ODEJoint::ApplyAdaptiveDamping(unsigned int _index,
const double _damping)
{
/// \TODO: hardcoded thresholds for now, make them params.
static double vThreshold = 0.01;
static double fThreshold = 1.0;
double f = this->GetForce(_index);
double v = this->GetVelocity(_index);
if (fabs(v) < vThreshold && fabs(f) > fThreshold)
{
// guess what the stable damping value might be based on v.
double tmpDStable = f / (v/fabs(v)*std::max(fabs(v), vThreshold));
// debug
// gzerr << "joint [" << this->GetName()
// << "] damping[" << _damping
// << "] f [" << f
// << "] v [" << v
// << "] f*v [" << f*v
// << "] f/v [" << tmpDStable
// << "] cur currentKd[" << _index
// << "] = [" << currentKd[_index] << "]\n";
// limit v(n+1)/v(n) to 2.0 by multiplying tmpDStable by 0.5
return std::max(_damping, 0.5*tmpDStable);
}
else
return _damping;
}
//////////////////////////////////////////////////
void ODEJoint::KpKdToCFMERP(const double _dt,
const double _kp, const double _kd,
double &_cfm, double &_erp)
{
/// \TODO: check for NaN cases
_erp = _dt * _kp / (_dt * _kp + _kd);
_cfm = 1.0 / (_dt * _kp + _kd);
}
//////////////////////////////////////////////////
void ODEJoint::CFMERPToKpKd(const double _dt,
const double _cfm, const double _erp,
double &_kp, double &_kd)
{
/// \TODO: check for NaN cases
_kp = _erp / (_dt * _cfm);
_kd = (1.0 - _erp) / _cfm;
}
//////////////////////////////////////////////////
void ODEJoint::SetDamping(unsigned int _index, double _damping)
{
if (_index < this->DOF())