Charging Station Switch Isolation for Robotic Mower Surge Protection

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Solution Overview

Problem

Outdoor robotic work tools, such as robotic lawn mowers, are vulnerable to high voltage electrical surges during thunderstorms, which can damage equipment like power supply units and electronics due to lightning strikes, necessitating an improved surge protection system.

Innovation Solution

The system employs an electrical switch arrangement that can be activated and deactivated to isolate or reconnect electric units, with a distinct movement direction for charging and protection modes, and uses weather data to determine when to engage or disengage the protection mode, ensuring the robotic work tool and charging station are safeguarded during storms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electrical switch arrangement is activated to protect against lightning strikes, then the reliability of electrical components is improved, but the ease of operation deteriorates due to the need for mode switching between charging and protection

Engineering Contradiction:
Improveprotection against electrical surgesVSAvoidmode switching complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system automatically detects weather conditions and switches between charging mode and protection mode without user intervention. The control unit monitors weather data and autonomously activates or deactivates the electrical switch arrangement, eliminating the need for manual mode switching while maintaining reliable surge protection during storms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses weather data feedback to dynamically control the electrical switch arrangement. The control unit receives weather information, processes it, and adjusts the switch state accordingly - keeping the system in protection mode when storm conditions are detected and switching to charging mode when conditions are safe, thereby resolving the contradiction between automatic protection and operational simplicity.

Inventive Principle:
Principle #23Feedback

2Reliability

If the electrical switch arrangement isolates electric units during charging, then the protection against electrical surges is improved, but the use of energy deteriorates due to interruption of charging process

Engineering Contradiction:
Improvesurge protection during chargingVSAvoidcharging efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The electrical switch arrangement dynamically changes its state based on real-time weather conditions. During normal conditions, the switch remains deactivated allowing continuous charging. When storm conditions are detected, the switch dynamically transitions to the activated state to provide surge protection, and automatically returns to deactivated state after the storm passes, thereby maintaining charging efficiency while providing protection when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs periodic weather monitoring and conditional switching between charging and protection modes. The control unit continuously checks weather data and periodically adjusts the switch state, enabling the system to alternate between charging operation and surge protection based on external conditions, thus resolving the contradiction between maintaining charging efficiency and providing surge protection.

Inventive Principle:
Principle #19Periodic action

3Reliability

If a grounding rod and protection circuitry are used, then the protection against electrical surges is improved, but the device complexity increases

Engineering Contradiction:
Improvelightning strike protectionVSAvoidprotection system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the grounding rod, electrical switch arrangement, and control unit into an integrated protection system within the charging station. Rather than adding separate complex protection devices, the system merges multiple protection functions into a unified structure that leverages existing charging station components, thereby providing comprehensive lightning strike protection while minimizing additional device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electrical switch arrangement serves multiple functions: it acts as a surge protection device during storms, a charging enablement mechanism during normal conditions, and a mode transition controller. This multi-functionality eliminates the need for separate dedicated protection devices, reducing overall system complexity while maintaining reliable lightning strike protection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4032385B1Electrical surge protection for an outdoor robotic work tool system
Publication Date: 2024.05.22 HUSQVARNA AB
  • EP4032385B1 patent drawingFigure 1A~1B
  • EP4032385B1 patent drawingFigure 2A~2B
  • EP4032385B1 patent drawingFigure 3

AI summary

The present disclosure relates to a method for a robotic work tool system (250), where the method comprises controlling (S100) the movement of an outdoor robotic work tool (100), and controlling (S400) the outdoor robotic work tool (100) to move an activation member (215) at an outdoor robotic work tool charging station (200) used for charging at least one rechargeable electric power source (155) of the outdoor robotic work tool (100). The movement is made in an activation direction (A1) such that an electrical switch arrangement (216) is activated and a protect mode is entered, wherein, upon activation, the electrical switch arrangement (216) is used for isolating at least one electric unit (220, 221, 222, 223, 224) from at least one electrical connection (230, 231, 232, 233, 234). Upon de-activation the electrical switch arrangement (216) is used for electrically connecting the electric unit (220, 221, 222, 223, 224) to said electrical connection (230, 231, 232, 233, 234).