Lifting Trajectory Replanning With Flexible Endpoint Reordering
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Solution Overview
Problem
Current methods for trajectory planning in lifting devices, such as gantry cranes, face challenges in efficient replanning, especially when end points change during operation, requiring significant computational effort and often compromising real-time capability and collision avoidance.
Innovation Solution
The method involves planning individual movements along each direction independently, using kinematic restrictions and filtering to ensure continuous differentiability, allowing for efficient and flexible replanning by projecting new end points and adjusting movements to avoid obstacles, with the option to check for collisions and adjust the trajectory accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional trajectory planning methods are used for lifting devices, then the trajectory can be planned from starting point to end point, but the computational complexity increases significantly when replanning is required with changed end points
Solution Approach 1:
The patent divides the trajectory planning problem into two independent segments: a first direction (e.g., horizontal) and a second direction (e.g., vertical). Each direction is planned separately with its own trajectory function, allowing independent optimization and replanning without recalculating the entire trajectory, thus reducing computational complexity while maintaining adaptability.
2Reliability
If comprehensive trajectory planning is performed to ensure collision-free movement, then safety is improved, but the planning time and computational resources increase
Solution Approach 1:
The patent defines working ranges and obstacle constraints in advance before trajectory execution. By pre-establishing the boundaries and safety zones, the system can perform rapid replanning when end points change, as the fundamental constraints are already known, reducing planning time while maintaining collision avoidance through the predefined safety framework.
3Adaptability or versatility
If the end point is changed during load movement, then operational flexibility is improved, but the trajectory must be replanned which increases computational effort
Solution Approach 1:
By segmenting the trajectory into independent directional components, the system can replan only the affected direction when an end point changes, rather than recalculating the complete multi-dimensional trajectory. This selective replanning approach maintains operational flexibility while significantly improving replanning efficiency by reducing computational scope.
4Stability of the object's composition
If smooth continuous trajectories are planned to avoid load oscillation, then movement quality is improved, but the trajectory planning becomes more complex
Solution Approach 1:
The patent applies separate smoothing functions to each directional trajectory component independently. This segmented approach maintains load movement stability through continuous, oscillation-free trajectories while reducing planning complexity by avoiding the need to solve a single complex multi-dimensional smoothing problem, instead using simpler one-dimensional smoothing for each direction.
Data Source
Figure 1
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Figure 3a~3b
AI summary
In order to specify a method for controlling a lifting device (1) that is improved compared to the prior art, which moves a load (8) along a first direction of movement (X) and along a second direction of movement (Y) within a specified working area (15) of the lifting device (1) from a starting point (A) to an end point (E), individual movements (TEx, TEY) are planned for the first direction of movement (X) and for the second direction of movement (Y), by means of which the load (8) is moved further along the directions of movement (X, Y) and brought to a newly specified end point (En).