Walking Controller for Muscu-loskeletal Human Model

Biped Control is Difficult

• Balance, Robustness, Looking natural• Various stylistic gaits

PETMANBoston Dynamics

ASIMOHonda

HUBOKAIST

Biped Control is Difficult?

Yin et al. 2007 Wang et al. 2009da Silva et al. 2008a,b

Muico et al. 2009

Sok et al. 2007

Biped Control is Difficult?

Yin et al. 2007 Wang et al. 2009da Silva et al. 2008a,b

Muico et al. 2009

Coros et al. 2010

Lasa et al. 2010Liu et al. 2010 Wu et al. 2010

Sok et al. 2007 Lee et al. 2010

Musculoskeletal Model

• In biomechanics, musculoskele-tal model have been used to analyze, simulate human movement

• More similar to human : investi-gate “how real human moves”

• Medical application : orthope-dics surgery

Goal

• Controller for musculoskeletal model– Responding to perturbation

• Reasonable computation time

Related Work

• Biomechanical model– Torso [Zordan 2004], neck [Lee 2006], hand

[Tsang 2005], face [Sifakis 2005]

• Deformable foot model– [Jain 2011], [Pauly 2004]

• Musculoskeletal simulation– [Thelen 2003;2006] [Lee 2006;2009] [Tsang

2005] [Sifakis 2005] [Komura 2000]

Hill-Type Muscle Model

• Serial element : tendon• Contractile element• Parallel element pennation angle α

Hill-Type Muscle Model

• Force-length relation of tendon• Active force-length relation of muscle• Passive force-length relation of muscle• Force-velocity relation of muscle

Activation / Excitation

• Activation : level of activation of muscle fiber (contractile element)

• Excitation : electrical stimulus (neu-ral signal)

Dynamics of Musculoskeletal Sys-tem

• Activation dynamics

Dynamics of Musculoskeletal Sys-tem

• Activation dynamics

• Contraction dynamics

Dynamics of Musculoskeletal Sys-tem

• Activation dynamics

• Contraction dynamics

• Forward dynamics (equations of mo-tion) ),()(),()( qqFqqqCtqM

Our Model

• 23 degrees of freedom• 66 muscles• Joint limit force• Use OpenSim for muscu-

loskeletal dynamics and Hill-type muscle model

Computing Muscle Force

• – : joint torques, n : # of dof– : muscle forces, m : # of muscle– : moment arm matrix

• Resolve redundancy of muscle force• Minimum norm solution by pseudo inverse• f_min < f < f_max• Optimization

Thank you