Massachusetts Institute of Technology
Sign in | Create Account

Dynamic Walking 2010. Greg Sawicki. Mechanics and control of a compliant muscle-tendon during cyclic contractions

Compliant mechanical behavior of the lower-limb can capture the basic dynamics of stable walking and running across a range of speeds, but the neuromechanical mechanisms responsible for robust, spring-like limb dynamics are not entirely clear. In order for a compliant muscle-tendon unit to behave similar to an elastic spring, the mechanics of active (muscle fascicles) and passive (series-elastic tendon and aponeurosis) tissues must be appropriately coordinated (i.e. ‘tuned’) within the movement cycle. This ‘tuning’ involves adjusting the pattern of muscle activation to modulate muscle force/stiffness output (via intrinsic force-length and force velocity properties) in order to match the loading profile imposed by the environment through series elastic structures within the muscle-tendon unit. Using bullfrog plantaris muscle-tendon, a servo-controlled muscle ergometer and sonomicrometry, we have developed a novel experimental framework to study the neuromechanics of a compliant muscle -tendon unit in vitro. In our initial experiments we employed classical work-loop techniques to understand how the feedforward (i.e. open-loop) muscle activation pattern (timing, magnitude and duration of stimulation) influences muscle-tendon unit net work output and internal energy exchange between muscle fascicles and series-elastic tissues. First I will present results demonstrating conditions that lead to ‘tuned’ elastic behavior of a compliant muscle-tendon unit. Then I will discuss plans to extend our framework and address the relative roles of neural feedback (length and/or force) and muscle-tendon architecture in stabilizing perturbations to steady-state, ‘tuned’ elastic cycles.

Comments (0)

It looks like no one has posted a comment yet. You can be the first!

You need to log in, in order to post comments. If you don’t have an account yet, sign up now!

Dynamic Walking 2010

Dynamic Walking 2010

Category: Education | Updated 4 years ago

Created
August 04, 2010 16:58
Category
License
All Rights Reserved (What is this?)
Additional Files


Viewed
2979 times

More from Dynamic Walking 2010

Dynamic Walking 2010. Michael Goldfarb. Implicit Control of a Powered Knee and Ankle Prosthesis.

Dynamic Walking 2010. Michael Goldf...

Added 4 years ago | 00:28:29 | 2265 views

Dynamic Walking 2010. Tom Roberts. Fast, cheap and out of control: dynamic interactions of elastic structures and muscle motors

Dynamic Walking 2010. Tom Roberts. ...

Added 4 years ago | 00:44:10 | 2640 views

Dynamic Walking 2010. Ian Manchester. Regions of Attraction to Limit Cycles of Nonlinear Hybrid Systems

Dynamic Walking 2010. Ian Mancheste...

Added 4 years ago | 00:25:08 | 4926 views

Dynamic Walking 2010. Rodger Kram. Passive Elastic Running Prostheses; Very Good, But Not Yet Better.

Dynamic Walking 2010. Rodger Kram. ...

Added 4 years ago | 00:37:55 | 2543 views

Dynamic Walking 2010. Emanuel Todorov. Linearly-solvable optimal control: Theory and applications

Dynamic Walking 2010. Emanuel Todor...

Added 4 years ago | 00:33:38 | 2654 views

Dynamic Walking 2010. Waleed Farahat. Optimal Workloop Energetics of Muscle-Actuated Systems: An Impedance Matching View

Dynamic Walking 2010. Waleed Faraha...

Added 4 years ago | 00:41:49 | 2864 views