Robotic Interception

For the robotic interception of slow maneuvering objects, an Active Prediction, Planning and Execution (APPE) system was developed. The prediction module incorporates a vision system for:

  • object identification,
  • determination of a pre-grasping Cartesian frame, and
  • visual tracking of this frame for object-path prediction.

Specifically, a Kalman filter is used for both tracking and for long-range path prediction. The predicted object motions are fed into the planning module to determine the robot’s optimal trajectories for rendezvous with the object at a pre-grasping location. The motion planning technique developed comprises a two-level search methodology. In the upper level, the objective is to determine the optimal rendezvous location along the object’s predicted path. For a given rendezvous location, the second level can be seen as solving the classical time-optimal point-to-point (PTP) problem, thus simultaneously returning to the upper level: (i) an objective-function value, namely best interception time, and (ii) corresponding optimal robot motion to the specific end point.

Two novel methods were also developed for the robotic-interception of fast-maneuvering objects which do not require a priori information on the moving-object’s motion. Both techniques combine a navigation-guidance-based method with a conventional object-tracking technique. Thus, they are classified as¬†hybrid¬†interception schemes with two phases: Phase I, during which the robot is under the control of a navigation-guidance-based technique, and Phase II, during which the robot’s control is switched to a conventional tracking method.

For the first proposed method, an Ideal Proportional Navigation Guidance (IPNG) technique is used during Phase I. For the second proposed method, the augmented form of the IPNG technique is suggested for Phase I, when a reliable estimation of the target’s acceleration can be provided to the interceptor. Both techniques were modified to reflect the greater mobility of a robotic manipulator over an airborne missile for robotic interception of fast-maneuvering targets.