Robotic Lawn Mower Boundary Pivoting for Border-Edge Cutting
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Solution Overview
Problem
Robotic lawn mowers have a limited ability to cut grass close to objects and borders outside the defined cutting area, resulting in uncut grass due to the mower's design hindering access and the risk of cutting outside the intended boundary.
Innovation Solution
A robotic lawn mower with a control unit that positions the mower to maintain a shortest distance to the boundary, allowing the cutting disc to perform an arcuate movement close to borders while preventing cutting outside the boundary, using drive wheels that turn in different directions and a navigation system for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cutting unit is arranged at the underside of the lawn mower body, then the mower can cut grass in the operation area, but the body and wheels hinder the cutting unit from reaching grass close to objects and borders
Solution Approach 1:
The cutting unit is made movable relative to the mower body through a positioning system. The control unit adjusts the cutting unit's position dynamically, enabling it to extend beyond the body's usual footprint when approaching borders, thus resolving the contradiction between the fixed body structure and the need for border-close cutting capability
Solution Approach 2:
The cutting system is segmented into a movable cutting unit that can be independently positioned relative to the main body. This segmentation allows the cutting unit to be decoupled from the body's structural constraints, enabling it to reach close to borders while the body maintains its stable configuration
2Productivity
If the robotic lawn mower approaches a boundary at various angles, then it can cover more area, but it risks cutting outside the intended boundary
Solution Approach 1:
The control unit continuously monitors the mower's position relative to the boundary and adjusts the cutting unit's position and the mower's approach angle in real-time. This feedback mechanism ensures that regardless of the approach angle, the cutting unit maintains the correct distance from the boundary, preventing over-cutting while maximizing area coverage
Solution Approach 2:
The system dynamically changes the positioning parameters of the cutting unit based on the approach angle and boundary distance. By adjusting these parameters, the system maintains precise boundary accuracy while accommodating various approach angles for improved productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective cutting of grass close to borders without exceeding the boundary, regardless of the angle of approach, by strategically positioning the mower and controlling its movement to maintain an optimal distance from the boundary, ensuring a clean cut while preventing overreach.
Implementation Method 1
An electric control signal may be transmitted through the boundary wire thereby generating an (electro-) magnetic field emanating from the boundary wire. The robotic working tool is typically arranged with one or more sensors adapted to sense the control signal.
Data Source
AI summary
The present disclosure relates to a robotic lawn mower (100) comprising a body (140), at least two drive wheels (130a, 130b) arranged along a drive wheel axis (145) with a center (146) that is positioned between the drive wheels (130a, 130b). The robotic lawn mower (100) further comprises a control unit (110) and at least a first rotatable grass cutting disc (160). When the robotic lawn mower (100) is approaching a boundary (220) of an operation area (610), the control unit (110) is adapted toposition the robotic lawn mower (100a) such that there is a shortest distance (ds) between the center (146) and the boundary (220), and tocontrol the drive wheels (130a, 130b) to turn in mutually different directions such that the second end portion (102) of the robotic lawn mower (100a, 100b, 100c) performs an arcuate movement along a cutting arc (210), enabling the first cutting disc (160) to cut grass within the cutting arc (210).The boundary (220) is positioned between a border (139) and the operation area (610), and where the shortest distance (ds) admits the cutting arc (210) to have a closest arc portion (211) that is closest to the border (139) without passing the border (139).