A generalized interactive dynamic simulation for multi-rigid-body systems

Dynamic simulation with contact interactions arises in many application domains such as virtual reality (VR), graphics, robot motion simulators, and computer games. This dissertation presents a generalized dynamic simulator, called I-GMS, which can simulate motions of multi-rigid-body systems with contact interaction in virtual environments. Our prototype dynamic simulator I-GMS is designed to meet two important goals: generality and interactivity. By generality, we mean a dynamic simulator that can easily support various systems of rigid bodies. Other existing dynamic simulators usually can only be applied to specific types of rigid-body systems. In addition, I-GMS is designed to incorporate both internal and external (active) contact interaction. The former arise from contacts between the bodies in the multi-rigid-body system, while the latter are due to contacts inserted into the system through user interaction.; To provide this generality, we have developed I-GMS in an object-oriented framework. In fact, I-GMS supports various systems of rigid bodies, ranging from a single free flying rigid object to complex linkages such as those needed for robotic systems or human body simulation.; For efficiency and accuracy, we have developed a hybrid scheme for simulating internal contacts among the rigid bodies in the presence of friction. In our hybrid scheme, two impulse-based methods are exploited so that different impulse methods are applied adaptively depending on whether the current contact situation is characterized as ‘bouncing’ or ‘steady’. This adaptive scheme enables us to avoid the non-existent solution problem often faced when solving contact problems with Coulomb friction.; Haptic interaction is used to enable active contact interaction. This is implemented in I-GMS using the PHANToM haptic device which runs as an integrated part of I-GMS. In particular, we have applied haptic interaction to support on-line editing and modification of trajectories.; In this dissertation, we describe in detail the approach we have taken in I-GMS to provide both generality and interactivity. Simulation examples are given for various multi-rigid-body systems with haptic interaction. Also, we show results of applying our hybrid scheme for handling contact to balls falling and colliding with each other on a flat surface in three-dimensional space.