In this work, we optimally control the upright gait of a three-dimensional symmetric bipedal walking model with flat feet. The whole walking cycle is assumed to occur during a fixed time span while the time span for each of the cycle phases is variable and part of the optimization. The implemented flat foot model allows to distinguish forefoot and heel contact such that a half walking cycle consists of five different phases. A fixed number of discrete time nodes in combination with a variable time interval length assure that the discretized problem is differentiable even though the particular time of establishing or releasing the contact between the foot and the ground is variable. Moreover, the perfectly plastic contact model prevents penetration of the ground. The optimal control problem is solved by our structure preserving discrete mechanics and optimal control for constrained systems (DMOCC) approach where the considered cost function is physiologically motivated and the obtained results are analyzed with regard to the gait of humans walking on a horizontal and an inclined plane.

References

1.
Safonova
,
A.
, and
Hodgins
,
J.
,
2007
, “
Construction and Optimal Search of Interpolated Motion Graphs
,”
ACM Trans. Graph.
26
(
3
), p.
106
.
2.
Ren
,
C.
,
Zhao
,
L.
, and
Safonova
,
A.
,
2010
, “
Human Motion Synthesis With Optimisation-Based Graphs
,”
Computer Graphics Forum
,
29
(
2
), pp.
545
554
.
3.
Delp
,
S. L.
,
Anderson
,
F. C.
,
Arnold
,
A. S.
,
Loan
,
P.
,
Habib
,
A.
,
John
,
C. T.
,
Guendelmann
,
E.
, and
Thelen
,
D. G.
,
2007
, “
Opensim: Open-Source Software to Create and Analyze Dynamics Simulation of Movements
,”
IEEE Trans. Biomed. Eng.
,
54
(
11
), pp.
1940
1950
.
4.
Posa
,
M.
, and
Tedrake
,
R.
,
2012
, “
Direct Trajectory Optimization of Rigid Body Dynamical Systems Through Contact
,”
Workshop on the Algorithmic Foundations of Robotics
,
Springer
,
Berlin, Heidelberg
, p.
16
.
5.
Posa
,
M.
,
Cantu
,
C.
, and
Tedrake
,
R.
,
2014
, “
A Direct Method for Trajectory Optimization of Rigid Bodies Through Contact
,”
Int. J. Rob. Res.
,
33
(
1
), pp.
69
81
.
6.
Yunt
,
K.
, and
Glocker
,
C.
,
2005
, “
Trajectory Optimization of Mechanical Hybrid Systems Using SUMT
,” 2006 9th
IEEE
International Workshop on Advanced Motion Control
, Mar. 27–29, pp.
665
671
.
7.
Nowak
,
I.
,
2006
,
Relaxation and Decomposition Methods for Mixed Integer Nonlinear Programming
,
Springer Science & Business Media
,
Basel, Switzerland
.
8.
Sager
,
S.
,
2005
, “
Numerical Methods for Mixed-Integer Optimal Control Problems
,”
Ph.D. thesis
, Der Andere Verl, Tönning, Germany.
9.
Gerdts
,
M.
,
2006
, “
A Variable Time Transformation Method for Mixed-Integer Optimal Control Problems
,”
Optim. Control Appl. Methods
,
27
(
3
), pp.
169
182
.
10.
Ringkamp
,
M.
,
Ober-Blöbaum
,
S.
, and
Leyendecker
,
S.
,
2016
, “
On the Time Transformation of Mixed Integer Optimal Control Problems Using a Consistent Fixed Integer Control Function
,”
Math. Program.
, pp.
1
31
.
11.
Ferris
,
M. C.
, and
Munson
,
T. S.
,
2000
, “
Complementarity Problems in GAMS and the PATH Solver1
,”
J. Econ. Dyn. Control
,
24
(
2
), pp.
165
188
.
12.
Geyer
,
H.
,
Seyfarth
,
A.
, and
Blickhan
,
R.
,
2006
, “
Compliant Leg Behaviour Explains Basic Dynamics of Walking and Running
,”
Proc. R. Soc. B
,
273
, 2861–2867.
13.
Mombaur
,
K.
,
2009
, “
Using Optimization to Create Self-Stable Human-Like Running
,”
Robotica
,
27
(
03
), pp.
321
330
.
14.
Gross
,
D.
,
Hauger
,
W.
,
Schröder
,
J.
, and
Wall
,
W. A.
,
2010
,
Technische Mechanik-Band 3: Kinetik
,
Springer-Verlag
,
Heidelberg, Germany
.
15.
Kraft
,
D.
,
1985
, “
On Converting Optimal Control Problems Into Nonlinear Programming Problems
,”
Computational Mathematics Programming
(NATO ASI Series), Vol. 15, Springer, Berlin, Heidelberg, pp.
261
280
.
16.
Stryk
,
O.
, and
Bulirsch
,
R.
,
1992
, “
Direct and Indirect Methods for Trajectory Optimization
,”
Ann. Oper. Res.
,
37
(
1
), pp.
357
373
.
17.
Hairer
,
E.
,
Lubich
,
C.
, and
Wanner
,
G.
,
2006
,
Geometric Numerical Integration: Structure-Preserving Algorithms for Ordinary Differential Equations
,
Springer Science & Business Media
,
Berlin, Heidelberg
.
18.
Ober-Blöbaum
,
S.
,
Junge
,
O.
, and
Marsden
,
J. E.
,
2011
, “
Discrete Mechanics and Optimal Control: An Analysis
,”
ESAIM: Control, Optim. Calculus Var.
,
17
(
02
), pp.
322
352
.
19.
Campos
,
C. M.
,
Ober-Blöbaum
,
S.
, and
Trélat
,
E.
,
2015
, “
High Order Variational Integrators in the Optimal Control of Mechanical Systems
,”
Discrete Contin. Dyn. Syst.
,
35
(
9
), pp.
4193
4223
.
20.
Leyendecker
,
S.
,
Ober-Blöbaum
,
S.
,
Marsden
,
J. E.
, and
Ortiz
,
M.
,
2009
, “
Discrete Mechanics and Optimal Control for Constrained Systems
,”
Optim. Control Appl. Methods
,
31
(
6
), pp.
505
528
.
21.
Leyendecker
,
S.
,
Pekarek
,
D.
, and
Marsden
,
J. E.
,
2013
,
Structure Preserving Optimal Control of Three-Dimensional Compass Gait
,
Springer
,
Berlin, Heidelberg
, Chap. 8.
22.
Betsch
,
P.
, and
Steinmann
,
P.
,
2001
, “
Constrained Integration of Rigid Body Dynamics
,”
Comput. Methods Appl. Mech. Eng.
,
191
(
3–5
), pp.
467
488
.
23.
Betsch
,
P.
, and
Leyendecker
,
S.
,
2006
, “
The Discrete Null Space Method for the Energy Consistent Integration of Constrained Mechanical Systems—Part II: Multibody Dynamics
,”
Int. J. Numer. Methods Eng.
,
67
(
4
), pp.
499
552
.
24.
Terze
,
Z.
,
Müller
,
A.
, and
Zlatar
,
D.
,
2014
, “
Lie-Group Integration Method for Constrained Multibody Systems in State Space
,”
Multibody Syst. Dyn.
,
34
, p.
275
.
25.
Terze
,
Z.
,
Müller
,
A.
, and
Zlatar
,
D.
,
2015
, “
An Angular Momentum and Energy Conserving Lie-Group Integration Scheme for Rigid Body Rotational Dynamics Originating From Störmer–Verlet Algorithm
,”
ASME J. Comput. Nonlinear Dyn.
,
10
(
5
), p.
051005
.
26.
Koch
,
M. W.
, and
Leyendecker
,
S.
,
2016
, “
Structure Preserving Optimal Control of a Three-Dimensional Upright Gait
,”
Multibody Dynamics
,
Springer International Publishing
,
Switzerland
, pp.
115
146
.
27.
Betsch
,
P.
,
2005
, “
The Discrete Null Space Method for the Energy Consistent Integration of Constrained Mechanical Systems—Part I: Holonomic Constraints
,”
Comput. Methods Appl. Mech. Eng.
,
194
(
50–52
), pp.
5159
5190
.
28.
Marsden
,
J. E.
, and
West
,
M.
,
2001
, “
Discrete Mechanics and Variational Integrators
,”
Acta Numer.
,
10
, pp.
357
514
.
29.
Lee
,
T.
,
Leok
,
M.
, and
McClamroch
,
H.
,
2009
, “
Discrete Control Systems
,”
Springer Encyclopedia of Complexity and System Science
,
Springer
,
New York
, pp.
2002
2019
.
30.
Koch
,
M. W.
, and
Leyendecker
,
S.
,
2013
, “
Structure Preserving Simulation of Monopedal Jumping
,”
Arch. Mech. Eng.
,
60
(
1
), pp.
127
146
.
31.
Anderson
,
F. C.
, and
Pandy
,
M. G.
,
2001
, “
Dynamic Optimization of Human Walking
,”
ASME J. Biomech. Eng.
,
123
(
5
), pp.
381
390
.
32.
Li
,
Y.
,
Wang
,
W.
,
Crompton
,
R. H.
, and
Gunther
,
M. M.
,
2001
, “
Free Vertical Moments and Transverse Forces in Human Walking and Their Role in Relation to Arm-Swing
,”
J. Exp. Biol.
,
204
, pp.
47
58
.
33.
Park
,
J.
,
2008
, “
Synthesis of Natural Arm Swing Motion in Human Bipedal Walking
,”
J. Biomech.
,
41
(
7
), pp.
1417
1426
.
34.
Collins
,
S. H.
,
Adamczyk
,
P. G.
, and
Kuo
,
A. D.
,
2009
, “
Dynamic Arm Swinging in Human Walking
,”
Proc. R. Soc.
,
276
(
1673
), pp.
3679
3688
.
35.
Sasidharan
,
S.
,
Smitha
,
K. S.
, and
Thomas
,
M.
,
2012
, “
Human Gait Recognition Using Multisvm Classifier
,”
Int. J. Sci. Res.
,
11
(
3
), pp.
1907
1913
.
36.
de Quervain
,
I. A. K.
,
Steussi
,
E.
, and
Stacoff
,
A.
,
2008
, “
Ganganalyse Beim Gehen und Laufen
,”
Schweiz. Z. Sportmed. Sporttraumatologie
,
56
(
2
), pp.
35
42
.
37.
Betts
,
J. T.
,
2009
,
Practical Methods for Optimal Control and Estimation Using Nonlinear Programming
, 2nd ed.,
Cambridge University Press
,
New York
.
38.
Leyendecker
,
S.
,
2011
, “
On Optimal Control Simulations for Mechanical Systems
,” Habilitationsschrift, TU Kaiserslautern, Kaiserslautern, Germany.
39.
Uno
,
Y.
,
Kawato
,
M.
, and
Suzuki
,
R.
,
1989
, “
Formulation and Control of the Optimal Trajectory in Human Multijoint Arm Movement
,”
Biol. Cybern.
,
61
(
2
), pp.
89
101
.
40.
Simmons
,
G.
, and
Demiris
,
Y.
,
2005
, “
Optimal Robot Arm Control Using the Minimum Variance Model
,”
J. Rob. Syst.
,
22
(
11
), pp.
677
690
.
41.
Maas
,
R.
, and
Leyendecker
,
S.
,
2013
, “
Biomechanical Optimal Control of Human Arm Motion
,”
J. Multi-Body Dyn.
,
27
(
4
), pp.
375
389
.
42.
Soechting
,
J. F.
,
Buneo
,
C. A.
,
Herrmann
,
U.
, and
Flanders
,
M.
,
1995
, “
Moving Effortlessly in Three Dimensions: Does Donders' Law Apply to Arm Movement?
,”
J. Neurosci.
,
15
(
9
), pp.
6271
6280
.
43.
François
,
C.
, and
Samson
,
C.
,
1996
, “
Energy Efficient Control of Running Legged Robots—A Case Study: The Planar one-Legged Hopper
,” Institut National de Recherché en Informatique et en Automatigue,
Report No. 3027
.
44.
Roussel
,
L.
,
de Wit
,
C. C.
, and
Goswami
,
A.
,
1998
, “
Generation of Energy Optimal Complete Gait Cycles for Biped Robots
,”
IEEE
International Conference on Robotics and Automation
, pp.
2036
2041
.
45.
Fujimoto
,
Y.
,
2004
, “
Trajectory Generation of Biped Running Robot With Minimum Energy Consumption
,”
IEEE
International Conference on Robotics and Automation
, pp.
3803
3808
.
46.
Biess
,
A.
,
Liebermann
,
D.
, and
Flash
,
T.
,
2007
, “
A Computational Model for Redundant Human Three-Dimensional Pointing Movements: Integration of Independent Spatial and Temporal Motor Plans Simplifies Movement Dynamics
,”
J. Neurosci.
,
27
(
48
), pp.
13045
13064
.
47.
Friedmann
,
T.
, and
Flash
,
T.
,
2009
, “
Trajectory of the Index Finger During Grasping
,”
Exp. Brain Res.
,
196
(
4
), pp.
497
509
.
48.
Felis
,
M.
, and
Mombaur
,
K.
,
2013
, “
Modeling and Optimization of Human Walking
,”
Modeling, Simulation and Optimization of Bipedal Walking
,
Springer
,
Berlin, Heidelberg
.
You do not currently have access to this content.