Progress Done with integrating Bullet into Matlab simulator

Progress • Done with integrating Bullet into Matlab simulator. Now we can: – Use Bullet as physics engine (no constraint yet) – Use Bullet as a collision detection library

Working on • Revolute joint in ST • Integrating Bullet collision into ST • Adding Bullet constraint (Bullet have quite a number of constraints built-in)

What’s next • Finish ST + Bullet collision and iterative solver using OOOP (Quadratic program solver) • Compare Bullet and this method – Initial run show that in Bullet’s method, penetration is unavoidable and it takes long to recover from penetration. (See next slide) – Run test. Bullet. m to see

Initial result with Bullet

Initial result with Bullet • This is a very simple scene: drop a sphere into a plane ground below. • From step 10 -30: penetration! This is the main reason why this type of method cannot produce stable box stacking. With ST, there wont be any penetration • Next slide for linear velocity

Linear velocity of sphere • Along y axe: vel(Y): [0. 000000 -10. 166667 0. 000000] vel(Y): [0. 000000 -10. 333333 0. 000000] vel(Y): [0. 000000 -10. 500000 0. 000000] vel(Y): [0. 000000 -10. 666667 0. 000000] vel(Y): [0. 000000 -10. 833333 0. 000000] vel(Y): [0. 000000 -11. 000000 0. 000000] vel(Y): [0. 000000 0. 700000 0. 000000] Penetration vel(Y): [0. 000000 0. 560000 0. 000000] vel(Y): [0. 000000 0. 448000 0. 000000] vel(Y): [0. 000000 0. 358400 0. 000000] vel(Y): [0. 000000 0. 286720 0. 000000] vel(Y): [0. 000000 0. 229376 0. 000000] vel(Y): [0. 000000 0. 183501 0. 000000] vel(Y): [0. 000000 0. 146801 0. 000000] vel(Y): [0. 000000 0. 117441 0. 000000] • It’s clear that it takes the method many steps to recover a penetration.