Integration of collision detection with the multibody system library in Modelica

• Collision detection and response is one of the most difficult areas in simulation of multibody systems. Two known approaches, the impulse-based method and the force-based (penalty) method, can be applied for multibody simulation in Modelica. The impulse-based method requires instantaneous modification of some variables, but such modification is not always possible in Modelica. The force-based method leads to stiff ODE, which can be handled by solvers used with Modelica. We suggest a new way to express the penalty coefficients. The force-based method, however, requires computation of penetration depth which is time-consuming.We also suggest a method that combines the distance between bodies and the penetration depth into a single quantity used for force computation.Calling external functions is a preferable method integrate collision detection algorithms with practical physical models, since body geometry is stored externally. We describe an interface with collision detection tool SOLID.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Medicinteknik -- Annan medicinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Medical Engineering -- Other Medical Engineering (hsv//eng)

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