## Verimli Bir Ters Dinamik Yöntemi ile Gerçek Zamanlı Fiziksel Hareket Kontrolü

##### Göster/Aç

##### Tarih

2018##### Yazar

Kavafoğlu, Ersan

##### Ambargo Süresi

Acik erisim##### Üst veri

Tüm öğe kaydını göster##### Özet

Realistic character animations can be obtained using motion capture techniques. However,
these captured motions can be recorded only for predetermined scenarios. A virtual character
can have infinite variety of physical interactions with the virtual world, and it is not possible
to anticipate all these interactions and record appropriate motions. But in real life when
people interact with the surrounding environment, their motions are generated as a result of
physics laws. In physics based animation studies, it is aimed that the reaction movements
of the characters in the virtual environment occur in a natural way according to the laws of
physics.
In order to generate movements naturally, a simplified physical model needs to be controlled
only by applying joint torques. These joint torques are calculated by benefiting from studies
in fields such as robotics, biomechanics and physics. In order to be used in real-time ap plications, these calculations should be performed with very low processing costs, even for
multi-body systems with very high degrees of freedom.
In the literature, studies on physics-based animation can be grouped under two main titles:
local controllers and equations of motion based controllers. The most commonly used local
controller is the Proportional Derivative controller because of its simplicity of integration
and problem modeling. One of the main drawbacks of local controllers is the need to tune
gain parameters for each movement and character manually. Moreover they are not quite
stable at the speeds required for real-time applications.
In equations of motion based methods, modeling the problem and integration are more com plex. However, these methods generate better results which are more stable than the results
of local methods. Inverse dynamics constitutes the core component of equations of motion
based methods. In physics based animation, Newton-Euler and Euler-Lagrange methods are
used for inverse dynamics calculations. While Newton-Euler method is used to calculate the
torques iteratively, Euler-Lagrange method is often used to obtain the analytical equations of
motion needed for optimization problems.
In this thesis, we obtained generalized equations of motion for multi-body systems in 3D
space, whose orientations are represented by quaternions and consisting of rotational joints
with 3 degrees of freedom, by using Kane’s method. During this study, we have observed that
for complex multibody systems, it is not feasible to calculate the inverse dynamics solution
analytically neither by hand nor by using symbolic programming from these equations of
motions. In order to be usable in real-time applications, we derived a recursive inverse
dynamics algorithm from these equations. This algorithm is equivalent to recursive Newton Euler algorithms, which are often used in physics based animation applications. Unlike other
studies, since we obtain this algorithm from an analytical equation, we have introduced an
integrated approach that can be used for both motion planning and motion generation as
well as for inverse dynamics. We tested the results of our method in different scenarios and
observed that for all scenarios our method produces stable results even at large timesteps.
We also compared our method with some of the widely used methods in the literature.

##### Bağlantı

https://hdl.handle.net/11655/34209##### Koleksiyonlar

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