Robot meets world

A new way of reasoning about what happens when a robot's limb strikes an object could lead to more efficient and reliable robotic-control systems. When a robot is moving one of its limbs through free space, its behavior is well-described by a few simple equations. But as soon as it strikes something solid - when a walking robot's foot hits the ground, or a grasping robot's hand touches an object - those equations break down. Roboticists typically use ad hoc control strategies to negotiate collisions and then revert to their rigorous mathematical models when the robot begins to move again. Researchers at MIT's Computer Science and Artificial Intelligence Laboratory are hoping to change that, with a new mathematical framework that unifies the analysis of both collisions and movement through free space. The work could lead to more efficient controllers for a wide range of robotic tasks, but it could also help guarantee the stability of control algorithms developed through trial and error - or of untried, but promising, new algorithms. In a pair of recent papers, the researchers demonstrate both applications.