Trajectory planning with flexible replanning functionality—obstacle
AssigneeABB Schweiz AG
InventorsAndreas Stöger, Thomas J. Frauscher, Hubert Rams
Life of this patent
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Abstract
An improved method for controlling a lifting device, which moves a load along a first movement direction and along a second movement direction within a specified working area of the lifting device from a starting point to an end point. Individual movements are planned for the first movement direction and for the second movement direction, by which the load is moved on while avoiding a collision with a changed or newly specified obstacle.
Claims16
A method for controlling a lifting device which moves a load along a first movement direction and along a second movement direction within a specified working area of the lifting device in accordance with a specified trajectory from a starting point to an end point, the method comprising:
- at a command time point during the movement of the load, at least one of specifying a new obstacle for the movement of the load, which obstacle is arranged between the position taken on by the load at the command time point and the end point, is specified, or changing an existing obstacle, which is arranged between the position taken on by the load at the command time point and the end point, to a new obstacle for the movement of the load, and
- taking into account specified kinematic constraints of the lifting device, planning at least one individual movement for the first movement direction and for the second movement direction respectively, which planned individual movements determine a further movement of the load along the respective movement direction from the command time point onwards,
- wherein at least one individual movement for each movement direction ends in a projection of the end point onto the respective movement direction,
- wherein the planned individual movements are executed in accordance with a specified movement sequence in order to move the load further along the first movement direction and further along the second movement direction in accordance with a replanning trajectory resulting from the movement sequence of the planned individual movements without colliding with the new obstacle, and
- wherein the planned individual movements each comprise a position profile that can be continuously differentiated at least four times.
A lifting device for moving a load from a starting point to an end point in accordance with a specified trajectory within a specified working area of the lifting device, comprising:
- a load receiving element for receiving the load which is connected by at least one retaining element to a running element, the running element being movable along a first movement direction by a running element drive and the load receiving element being movable along a second movement direction by a lifting drive,
- a computing unit configured to read in, at a command time point during the movement of the load, at least one of an obstacle which is newly specified for the movement of the load and which is arranged between the position taken on by the load at the command time point and the end point, or an existing obstacle which is arranged between the position taken on by the load at the command time point and the end point and is changed to a new obstacle for the movement of the load,
- the computing unit being further configured to plan, taking into account specified kinematic constraints of the lifting device, an individual movement for the first movement direction and for the second movement direction respectively which define a further movement of the load along the respective direction of movement from the command time point onwards,
- wherein the individual movements end in each case in a projection of the end point onto the respective direction of movement,
- wherein the computing unit is configured to control the running element drive and the lifting drive of the lifting device in order to execute a planned individual movement for the first movement direction and for the second movement direction in accordance with a specified movement sequence and thus to move the load further along the first movement direction and along the second movement direction in accordance with a replanning trajectory resulting from the movement sequence of the planned individual movements without colliding with an obstacle, and
- wherein the planned individual movements each comprise a position profile that can be continuously differentiated at least four times.
Dependencies are inferred from the claim text.