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Biomechanical Properties

Efficient locomotion depends on the distribution of the weight and the muscle strength in an animal's body. For example, fish with heavy heads or tails will swim less efficiently and less gracefully than fish with relatively light heads and tails, while fish with either too weak or too stiff muscles will also suffer some degree of motor incompetence. The weight and the muscle strength distributions of the physics-based artificial fish are characterized by the tex2html_wrap_inline2330 and the tex2html_wrap_inline2350 of the model, respectively. We set these physical parameters of the model such that the corresponding distributions along the fish body are biologically plausible. For example, the nodes that form the head and the tail of the fish have less mass than those that form the middle part of the body.

The values of parameters used in our simulation are listed in Table  gif and Table  gif.

Node i Attributes
i=0, tex2html_wrap_inline2426 tex2html_wrap_inline2428
tex2html_wrap_inline2430 , tex2html_wrap_inline2432 tex2html_wrap_inline2434
tex2html_wrap_inline2436 tex2html_wrap_inline2438
i=21, 22 tex2html_wrap_inline2442



[The mass distribution of the artificial fish.] The mass distribution of the artificial fish. Refer to Fig. gif.  

Viscoelastic unit tex2html_wrap_inline2344 Attributes
Cross units, e.g. tex2html_wrap_inline2446 tex2html_wrap_inline2448
Muscle units: tex2html_wrap_inline2450 tex2html_wrap_inline2452
Remaining units, e.g. tex2html_wrap_inline2454 tex2html_wrap_inline2456
All units tex2html_wrap_inline2344 tex2html_wrap_inline2460



[The elasticity and viscosity constants of the artificial fish.] The elasticity and viscosity constants of the artificial fish. Refer to Fig. gif.  

Note that the elasticity constants are made large enough to provide the fish's body with the structural integrity that it requires for effective swimming.gif However, this results in a rather stiff dynamic system that needs a stable numerical solver to simulate its dynamics.


next up previous contents
Next: Muscles and Hydrodynamics Up: Viscoelastic Units Previous: Newtonian equations of motion
Xiaoyuan TuJanuary 1996