I found that there are several models using link-segment analysis that are used to model the human lower limb or human leg during walking. The models are also used to describe the human gait pattern and are also used for biped robot locomotion.
Can anybody used to human leg modelling help to explain when and why these models are used:
What are the mathematical equations that are usually used?
Thank you.
As far as I understand inverted pendulum models are used for studying equilibrum control. E.g., Alexandrov & Frolov work http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1430400/
The choose of number of links depends on the simulated task.
Inverted pendulum model is normally used when you want to describe walking, as in walking the center of mass (CoM) of the body moves in a ballistic trajectory, with the highest position being in the middle of the stance phase, just like an inverted pendulum. One link model is the simplest model to describe walking. Two-link model describes human leg as consist of two segments, while three-link model includes also the foot. These models are used for further locomotion analysis, such as stability during locomotion using different proportion of thigh-shank-foot. I've never heard about five- or seven-link-model to model human leg only. I would expect of a model including the trunk when you're talking about five- or seven-link-model.
Below are some examples of publications that investigate stability using segmented-model:
ijr.sagepub.com/content/27/8/919.abstract
www.ncbi.nlm.nih.gov/pubmed/11357549
Thanks for the answer. The five-link model consists of two legs' thigh and shank plus the torso/trunk. The seven-link model is the extension of the five-link model with the inclusion of foot for both legs.
In modelling human posture and human balance too little is known of the hughe importannce of having the anatomic and fysiologic ( masses and tensionlines, tensegrity) centre of the body , the thoracolumbar joint and by that the conusmedullaris in the right position ( a lordotic and extended curve between Th10 and L2. If a child can achieve such a natural curvature of the spine and the centre part stays as flexible as possible, you can expect durability of the locomotor system ( and more) .
Gyroscopicaly the TL joint acts as ( a unique in biology for man) as the coupling mechanism between a pendulum ( lower legs) and a reversed pendulum ( shoulder-arms) in order to balance the head in any position of both.
Therefore the care for good postures and flexibility in the spine in childhood is such an imperative task for parents and educators ( original mission of Orhopedics). A good posture and complete flexibility also prevents shearloading in joints as hips and knees, nowadays very early degenerative by that.
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