Constraint-based Simulation of Passive Suction Cups

Abstract

In this paper, we propose a physics-based model of suction phenomenon to achieve simulation of deformable objects like suction cups. Our model uses a constraint-based formulation to simulate the variations of pressure inside suction cups. The respective internal pressures are represented as pressure constraints which are coupled with anti-interpenetration and friction constraints. Furthermore, our method is able to detect multiple air cavities using information from collision detection. We solve the pressure constraints based on the ideal gas law while considering several cavity states. We test our model with a number of scenarios reflecting a variety of uses, for instance, a spring loaded jumping toy, a manipulator performing a pick and place task, and an octopus tentacle grasping a soda can. We also evaluate the ability of our model to reproduce the physics of suction cups of varying shapes, lifting objects of different masses, and sliding on a slippery surface. The results show promise for various applications such as the simulation in soft robotics and computer animation.

Real-Time Surface-Based Volume Constraints on Mass-Spring Model in Unity3D

“…The local deformation technique is used to improve the behavior of the volume preservation constraint because it distributes the preserving condition or the affected region on the surface model. As shown in (14), the volume constraint preserves all of the triangles and nodes on the surface which is not suitable for some materials with complex properties. To provide a flexible technique to get a smooth transition between global and local deformation, the weight vector is used to localize the volume correction.…”

“…In the BuildSystem() kernel, the GPU thread invokes the Jacobian buffer, volume buffer, Velocity buffer, and Force buffer to compute the left-hand and right-hand side of the system in (14) to compute the Lagrange multiplier. Therefore, we also need a temporary buffer to store the left-hand and right-hand as the scalar value.…”

“…Next, those two temporary buffers are used in the AccumulateForce() kernel to compute the new force for correcting the object's volume. Note that, we don't require an additional buffer to store the Lagrange multiplier, since it is easily found by the division of the righthand side and left-hand side of the linear system in (14). Each element of the Force buffer is then easily computed since each GPU thread has access to each element of the Jacobian vector correspondingly.…”

“…The meshless approach such as shape matching can simulate visually plausible and plastic deformation which considers only the surface structure of the deformable object [13]. Similarly, Pressure constraint based on the ideal gas law is applied to simulate the suction cups to reproduce the physics of suction cups of varying shapes [14].…”