Regulating Speed and Generating Large Speed Transitions in a - - PowerPoint PPT Presentation

Regulating Speed and Generating Large Speed Transitions in a Neuromuscular Human Walking Model

Seungmoon Song and Hartmut Geyer Robotics Institute Carnegie Mellon University

W911NR-11-1-0098

Local Reflex Control Has a Large Potential for Controlling Robotic Legs

Humanoid vs Human Control Local Reflex Control

1/10 Humanoid: HONDA (ASIMO), Boston Dynamics (PETMAN) CPG + reflex: Taga et al. (1991), Ogihara et al. (2001) Robotic ankle: iWalk BiOM CPG Reflex

Our Reflex Based Neuromuscular Walking Model Current Limitations

• Confined to the sagittal plane
• Only walks at a single speed

NM Model (Geyer et al., 2010), Ankle prosthesis (Eilenberg et al, 2010) 2/10

Walking Speed Adaptation of the Human Model

• 1. Neuromuscular Model
• 3. Speed Adaptation
• 2. Optimization

Control Groups and Underlying Principles

Left leg cycle Swing-leg retraction

(Seyfarth et al., 2003)

PD trunk control

(Gunther et al., 2003)

Knee stability

(Seyfarth et al., 2001)

Spring mass model & F+

(Geyer et al, 2003 and 2006)

Swing-leg Initiation

(Mochon et al., 1980)

Right leg cycle Right leg control NM Model (Geyer et al., 2010) 3/10

Walking Speed Adaptation of the Human Model

• 1. Neuromuscular Model
• 3. Speed Adaptation
• 2. Optimization

, Energy rate (Umberger, 2003) 4/10

Target speed Pain Energy cost

The Cost Function Includes Walking Speed, Energetic Cost, and Pain

, CMA-ES (Hansen, 2006) Cost fn. (Neptune et al., 2001)

Walking Speed Adaptation of the Human Model

• 1. Neuromuscular Model
• 3. Speed Adaptation
• 2. Optimization

Optimization Results for Steady Walking Matches Human Data

v (Murray et al., 1984), CE (Minetti et al., 2001), L & f (Hirasaki et al., 1999) 0.8ms-1 1.4ms-1 1.8ms-1 5/10

Nine Control Parameters Show Strong Trend

6/10

Generation of Speed Transition: Switch Between Steady Speed Walking Controls

7/10

Works for small speed transitions. Fails for large speed transitions!

8/10

Generation of Speed Transition: Explicit Transition Phase Control

9/10

Successful Generation of Speed Transition: Explicit Transition Phase Control

Conclusion

10/10

We extended a local reflex based walking control to regulate walking speed and generate large speed transitions between 0.8ms-1 and 1.8ms-1 An explicit transition control was required to generate large speed transitions To walk faster the model …

• leans forward
• makes stronger ankle push-off
• makes larger swing initiation