# Lecture 15 * ![](https://i.imgur.com/g8RrnUS.png) * is this system is stablity of PD control ![](https://i.imgur.com/XlUKuBG.png) * Here we are equating torque with the gains * as these forces are against the velocity we can say that system will be stable * so because of Kv term the system turns out to be asymmatotically stable * here all the decoupling forces are shown in kinetic energy term ![](https://i.imgur.com/2UKohi0.png) * But for performance i.e, trajectory following what to do ? but we need to have high gains. * now if we can't increase the gains high so what to do ? :[27:59](https://youtu.be/A6QEQFTBKnA?t=1679) * Rather than making a wrong estimate of V_hat you can just use zero estimate of v_hat because otherwise it might be dangerous. * ![](https://i.imgur.com/j7eJzuy.png) * Here we controled our robot in terms of its joint motion but In task oriented control intsetead of inverse kinematics. * ![](https://i.imgur.com/SkxazTr.png) * ![](https://i.imgur.com/pBqDX0J.png) * here we are basically moving only the end-effector with gradient force. * we can also add repulsive forces obstacles. * ![](https://i.imgur.com/7o7p9rG.png) * as this is not a point mass applying force will give rise to acceleration in different direction and other decoupling forces. * ![](https://i.imgur.com/lSC7taY.png) * ![](https://i.imgur.com/oxkeb9C.png) * ![](https://i.imgur.com/06FkeUB.png) * ![](https://i.imgur.com/bY5SR6d.png) ![](https://i.imgur.com/HMA7Vn0.png) ![](https://i.imgur.com/WktWB8b.png) * ![](https://i.imgur.com/gkZ6q32.png) * ![](https://i.imgur.com/bjUB1Bk.png) ![](https://i.imgur.com/qhZne2G.png) ![](https://i.imgur.com/lf2rKXk.png) ![](https://i.imgur.com/tJg71Nj.png) ![](https://i.imgur.com/A9XbhpD.png) ![](https://i.imgur.com/2DozQPh.png) ![](https://i.imgur.com/abnjYiZ.png) ![](https://i.imgur.com/ojGe0CK.png)