Robotic Work Tool Path Planning in Satellite-Shadowed Areas
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Solution Overview
Problem
Robotic work tools, such as lawnmowers, face challenges in maintaining accurate navigation in areas with low GPS signal reception, leading to positioning errors due to reliance on dead-reckoning, which can result in prolonged times and inefficient operation.
Innovation Solution
A robotic work tool system that operates using satellite navigation outside satellite-shadowed areas and deduced reckoning sensors inside these areas, minimizing navigational errors by optimizing time, distance, and maneuvering in these zones, with a controller determining area segmentation to enhance navigation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the robotic work tool relies on dead-reckoning in satellite-shadowed areas, then it can continue operation without satellite navigation, but positioning accuracy deteriorates leading to navigational errors
Solution Approach 1:
The operating area is segmented into satellite-visible areas and satellite-shadowed areas based on GPS signal quality. The controller identifies boundary regions and creates separate navigation strategies for each zone, allowing the system to maintain reliability in shadowed areas while preserving accuracy in visible areas.
Solution Approach 2:
The system performs preliminary identification of satellite-shadowed areas using map data and obstacle information before entering them. It pre-calculates optimal exit strategies and minimizes the time spent in low-accuracy zones by planning paths that quickly traverse shadowed areas and return to satellite-visible regions.
2Productivity
If the robotic work tool spends more time in satellite-shadowed areas, then it can complete more work in these zones, but navigational errors increase due to prolonged dead-reckoning
Solution Approach 1:
The controller pre-identifies satellite-shadowed areas using map data and pre-calculates optimal traversal paths that minimize time spent in these zones. The system plans to enter shadowed areas only when necessary and exits as quickly as possible to restore accurate GPS positioning.
Solution Approach 2:
The system prioritizes rapid traversal through satellite-shadowed areas rather than lingering to complete additional work tasks. It uses high-speed movement and direct paths to minimize the duration of dead-reckoning, accepting that some work in these zones may be deferred until GPS signal is restored.
3Area of stationary object
If the robotic work tool travels longer distances in satellite-shadowed areas, then it can service more of the operational area, but navigational error accumulates
Solution Approach 1:
The operational area is divided into zones based on GPS signal availability. The controller creates a map showing which areas can be serviced with high accuracy (satellite-visible) and which require low-accuracy dead-reckoning (satellite-shadowed), then prioritizes servicing the high-accuracy zones first.
Solution Approach 2:
The system minimizes the distance traveled through satellite-shadowed areas by using direct paths and avoiding unnecessary detours. It quickly traverses these zones to reach satellite-visible areas where accurate positioning can be restored, rather than extending operations deep into shadowed regions.
4Adaptability or versatility
If the robotic work tool performs more maneuvers in satellite-shadowed areas, then it can adapt to local features, but navigational error increases due to cumulative dead-reckoning mistakes
Solution Approach 1:
The controller uses pre-stored map data containing obstacle and feature information to plan maneuvers before entering satellite-shadowed areas. When GPS signal is lost, it relies on this pre-acquired knowledge to navigate around obstacles and complete necessary tasks without requiring additional dead-reckoning maneuvers.
Solution Approach 2:
The system extracts and utilizes pre-stored environmental information (obstacle locations, feature positions) from map data to compensate for the lack of real-time GPS positioning. This allows the robotic work tool to perform necessary maneuvers based on prior knowledge rather than real-time sensing, reducing the need for additional dead-reckoning operations.
Data Source
Figure 1
Figure 2~3A
Figure 3B~3C
AI summary
A robotic work tool system (200) comprising a robotic work tool (100) arranged to operate in an operational area (205) having one or more satellite-shadowed areas (SA), wherein the robotic work tool (100) is configured to operate according to the satellite navigation sensor (175) outside the one or more satellite-shadowed areas (SA) and according to the one or more deduced reckoning sensors (180) inside the one or more satellite-shadowed areas (SA), wherein a memory (120) is configured to store a map of the operating area, said map application indicting a number of obstacles (H, T), and wherein a controller (110, 240A) is configured to determine (510) a first segmentation of the operating area (205) by minimizing (520) a navigational error introduced in the one or more satellite-shadowed areas (SA).