Musculoskeletal Model for Simulation of Walking
[from the Dynamic Walking 2011 program]
This workshop will take place on Wednesday 20 July in the morning and will consist of two parts.
1. Musculoskeletal dynamics
We will first present the fundamental principles of musculoskeletal dynamics, including multibody dynamics and muscle dynamics. Participants will be given Matlab code to perform simulations of isolated muscle contractions and muscle-driven knee extension movements. Experiments will be performed to determine the effect of muscle properties and mass properties.
2. Musculoskeletal model for walking
Here we present a musculoskeletal model that we have developed for simulation of human walking (Ackermann and van den Bogert, J Biomech, 2010). This model consists of seven body segments, sixteen muscles, and visco-elastic ground contact with friction. Participants will receive a Matlab (MEX) function with the system’s dynamic state equation. They will learn how to simulate maximal isometric joint moments and simple open loop controlled movements to evaluate and test the model.
Participants will be expected to bring a laptop (Windows, Linux, or Mac OS) with Matlab installed (version 7.4 or later, student version is OK, no toolboxes needed). Participants will receive a flash drive with all software and data files, as well as the slide presentations.
Download the ZIP file and install it in a suitable place. Navigate to the "Tutorial" folder and open the PDF file with the powerpoint slides. The "Tutorial" folder will also contain the Matlab codes knee.m and muscle.m. The "gait2de_1.1" folder will contain the full body model. A precompiled MEX function is included for a few operating systems. To see which MEX function file extension you need, type "mexext" in Matlab. If the folder does not have the right MEX file for your version of Matlab, you can make your own from the source code page, or download one of these:
- gait2de.mexmac (Mac, 32 bit?)
- gait2de.mexw64 (Windows, 64 bit Matlab, this is probably the most common)
A video recording of the tutorial session is available here. Playback requires the RealAudio player, unfortunately. If someone is able to convert the stream into a regular file, please let me know (email@example.com).