Robotic work tool and a method for use in a robotic work tool comprising a lift/collision detection device
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Solution Overview
Problem
Existing robotic work tools, such as lawnmowers, face challenges in accurately distinguishing between lift and collision events due to false positives, which can impair operation and require complex, costly designs with multiple joystick models for different applications.
Innovation Solution
A robotic work tool with a lift/collision detection device comprising a first and second sensor element, connected to a controller that receives distance values and compares them to distinct thresholds to differentiate between lift and collision events, using different transmission ratios for horizontal and vertical movements to provide accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor arrangement is used for both lift and collision detection, then device complexity is reduced, but measurement precision deteriorates due to false positives between lift and collision detection
Solution Approach 1:
The single sensor arrangement is segmented into two distinct sensor elements (first sensor element and second sensor element) that measure different physical quantities. The first sensor element detects vertical displacement for lift detection, while the second sensor element detects horizontal displacement for collision detection. This segmentation allows both functions to be performed with high precision using a unified detection device structure.
Solution Approach 2:
The detection system transitions from detecting only vertical movement (single dimension) to detecting both vertical and horizontal movements (multiple dimensions). By adding the horizontal displacement detection capability through the second sensor element, the system can distinguish between lift events (vertical only) and collision events (horizontal component present), thereby improving measurement precision without increasing overall device complexity.
2Measurement precision
If multiple joystick models are manufactured for different detection requirements, then measurement precision is improved for specific applications, but manufacturing precision and adaptability worsen due to model-specific designs
Solution Approach 1:
The detection device is designed as a universal multi-functional unit that can accurately perform both lift detection and collision detection across different robotic work tool models. The single detection device incorporates two sensor elements that work together to provide model-independent detection capabilities, eliminating the need for model-specific joystick variations and enabling broad adaptability while maintaining high measurement precision.
Solution Approach 2:
Instead of creating different physical joystick models for different detection requirements, the system changes the detection parameters by using two different sensor elements within a single unified structure. This allows the same physical device to adapt to different detection needs (lift vs. collision) by processing signals from the two sensor elements differently, thereby achieving cross-model versatility without sacrificing detection accuracy.
Data Source
AI summary
A robotic work tool having a chassis, a cover and a controller for controlling the operation of the robotic work tool. The robotic work tool further has a lift/collision detection device (300) connected to the controller for providing sensor input, and which Hft/coUision detection device (300) includes a first sensor element (340) and a second sensor element (345). The controller (110) is configured to receive sensor input of a distance value indicating a distance between the first sensor element (340) and the second sensor element (345), determine that a lift has been detected, fay comparing the distance value with a lift detection threshold and/or determine that a collision has been detected, by comparing the distance value with a collision detection threshold, wherein the collision detection threshold is different from the lift detection threshold.