Motion planning and control for systems with multiple mobile objects

A system for controlling the movements of multiple robotic manipulators through a workspace, wherein the position of each manipulator is dependent on the configuration of a plurality of interconnected linkages, as defined by a plurality, n, of configuration joint settings corresponding to n degrees of freedom of the manipulator, the system comprising:

• a path planner for planning in advance a series of movements of each of a plurality robotic manipulators to provide a relatively coarse scale plan for the movements, wherein the path planner determines paths in a configuration space defined by n orthogonal axes corresponding to n configuration joint settings that define the position of each manipulator in three-dimensional space;
• and
• a path execution module operable to move the manipulators in accordance with the relatively coarse scale plan provided by the path planner, and including a fine-scale artificial force field collision avoidance subsystem, to provide control signals to the manipulators such that they are moved along paths determined in part by the path planner and in part by the collision avoidance subsystem, whereby the manipulators are moved from starting points to desired endpoints without collisions with each other or with any stationary obstacles, and wherein the path execution module includes
• a waypoint interpolator, to generate finer resolution paths from path data provided by the path planner,
• a control law module for generating control signals based on the finer resolution paths through configuration space and predicted states of the manipulators;
• a collision avoidance force model, for generating collision avoidance control signals based on mutual proximity of the manipulators and any other objects in the workspace, and
• means for combining the collision avoidance control signals and the control signals from the control law module, wherein collision avoidance is achieved by modifying the paths planned through the configuration space.

A method for planning and executing movements of multiple mobile objects through a workspace, wherein the position of each object is dependent on the configuration of a plurality of interconnected linkages, as defined by a plurality, n, of configuration settings corresponding to n degrees of freedom of the object, the method comprising the steps of:

• planning in advance a path having series of movements of each of the mobile objects to provide a relatively coarse scale plan for the movements, wherein the planning step determines paths in a configuration space defined by n orthogonal axes corresponding to n configuration settings that define the position of each object in three-dimensional space;
• controlling the path execution in such a way as to move the objects primarily in accordance with the relatively coarse scale plan provided by the planning step, and including an additional step of generating collision avoidance object control signals based on an artificial force field model, wherein the step of controlling the path execution movement includes
• interpolating between coarse path planning waypoints to generate finer resolution planned paths,
• generating control signals based on the finer resolutions paths through configuration space and predicted configuration settings of the objects,
• generating collision avoidance control signals based on mutual proximity of objects in the workspace, and
• combining collision avoidance control signals and the control signals based on the finer resolution planned path, wherein collision avoidance is achieved by modifying the paths planned through the configuration space;
• and
• applying control signals to the movable objects such that they are moved along paths determined in part by the path planning step and in part by the step of controlling the path execution, whereby the objects are moved from starting points to desired endpoints without collision with each other or with any stationary obstacles.

A method for planning and executing movements of multiple robotic manipulators through a workspace, wherein the position of each manipulator is dependent on the configuration of a plurality of interconnected linkages, as defined by a plurality, n, of configuration joint settings corresponding to n degrees freedom of the manipulator, the method comprising the steps of:

• planning in advance a path having series of movements of each of the manipulators to provide a relatively coarse scale plan for the movements, wherein the planning step determines paths in a configuration space defined by n orthogonal axes corresponding to n configuration settings that define the position of each manipulator in three-dimensional space;
• controlling the path execution in such a way as to move the manipulators primarily in accordance with the relatively coarse scale plan provided by the planning step, and including an additional step of generating collision avoidance object control signals based on an artificial force field model, wherein the step of controlling the path execution movement includes
• interpolating between coarse path planning waypoints to generate finer resolution planned paths,
• generating control signals based on the finer resolution paths through configuration space and predicted configuration settings of the manipulators,
• generating collision avoidance control signals based on mutual proximity of manipulators and any obstacles in the workspace, and
• combining the collision avoidance control signals and the control signals based on the finer resolution planned paths, wherein collision avoidance is achieved by modifying the paths planned through the configuration space;
• and
• applying control signals to the manipulators in such that they are moved along paths determined in part by the path planning step and in part by the step of controlling the path execution, whereby the manipulators are moved from starting points to desired endpoints without collisions with each other or with any stationary obstacles.