|
|
|
|
| Learn More | Task Planning and Operations: Obstacle Avoidance |
|
|
| Videos |
|
| The goal of Obstacle Avoidance |
The goal of obstacle avoidance technology is to permit a robot to work in an obstacle-strewn environment without damaging itself or any of the obstacles it encounters.
The basis for this development is the use of artificial potential force fields to analytically represent the "closeness" of a manipulator link to an object (moving or otherwise) which has a known location in the workspace.
Based on the accumulation of all these forces, the resultant can be represented as generalized forces at the manipulator end-effector, at the system’s actuators, or transferred to the hand-grip of the manual controller to provide a basis for decision making to best avoid the obstacles in the workspace.
|
|
| Background Information |
Surprisingly, the problem of obstacle avoidance has not been adequately treated for complex robot systems (such as Robonaut) to operate among all but the simplest of obstacle arrays. In the past, the computational demands were a barrier.
With the advent of low cost gigaflop processors, this is no longer the case. Also, industrial robots tended to have unattractive appendages and link configurations, making their analytical description difficult to generalize. As robot design has improved (especially for space manipulators), robots have become slimmer and more "smooth" in their shape.
This means that fairly simple geometric models of the links can satisfactorily represent them analytically. In fact, the present representation is a cyli-sphere, a cylinder with a half-sphere on each end. Given similar representation for the objects (pipes, trusses, tools, other robots, etc.) in the workspace, it becomes possible to accurately represent the minimum distance d between n links and m objects.
This minimum distance can be made inversely proportional to a force, which is the basis for a potential field that is continuous and fully differentiable.
The forces can be aggregated into a total force concept to be represented either at the end-effector as resistive forces, at the respective actuators as torques, or at the manual controller hand-grip as a kinesthetic force felt by the operator.
|
|
|
|
