Lawn Mower Sensor Interference Reduction via Periodic Activation
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Solution Overview
Problem
Lawn mowers face issues with simultaneous signal management from multiple sensors, leading to interference and inaccurate grass cutting due to the presence of active elements, resulting in unsatisfactory accuracy, homogeneity, and completeness of the cutting operation.
Innovation Solution
The lawn mower employs a control unit with a selection circuit that sequentially activates and deactivates sensors with oscillators, using MOS-type active elements and detecting elements to generate detection signals representative of distance, thereby reducing interference and optimizing signal reception quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If multiple sensors with active elements are used simultaneously, then the detection capability and automation level are improved, but signal interference between sensors increases and measurement accuracy deteriorates
Solution Approach 1:
The patent applies periodic action by sequentially activating and deactivating oscillators in different sensors at different time intervals. Instead of all sensors operating simultaneously, the control unit activates oscillators in a sequential manner, allowing each sensor to operate periodically without interfering with others. This temporal separation resolves the signal interference problem while maintaining high automation through the control unit's coordination of multiple sensors.
2Adaptability or versatility
If multiple sensors with active elements are used simultaneously, then the detection capability is improved, but signal interference between sensors increases
Solution Approach 1:
The control unit implements periodic action by sequentially activating oscillators in different sensors at different time intervals. This temporal separation allows multiple sensors to operate without simultaneous signal interference, while still providing comprehensive detection capability through the coordinated operation of all sensors over time.
Solution Approach 2:
The control unit acts as an intermediary that manages the operation of multiple sensors. It coordinates the activation and deactivation of oscillators, ensuring that sensors operate in a controlled sequence rather than simultaneously. This intermediary control eliminates signal interference while maintaining the versatility of multiple sensors for different detection purposes.
3Measurement precision
If sequential activation of sensors is implemented, then signal interference is reduced and measurement accuracy is improved, but the complexity of the control system increases
Solution Approach 1:
The control unit is designed with multi-functionality, serving both as the central coordination hub for sequential sensor activation and as the signal processing unit. By making the control unit universal, the patent avoids adding separate dedicated control circuits for each sensor, thereby managing complexity while achieving accurate sequential operation of multiple sensors.
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
This solution enables accurate and complete grass cutting by minimizing sensor interference, ensuring reliable detection of grass height and external masses, and improving the overall performance of the lawn mower.
Implementation Method 1
each sensor comprises an oscillator adapted to generate a signal at an oscillation frequency which varies as a function of a distance between a detecting element of the sensor and an external mass
Data Source
AI summary
A lawn mower comprising: a frame (10); wheels and motors (20a;20b) for moving the frame (10) relative to a work surface (L); one or more blades (30) for cutting the grass on the work surface (L); a plurality of sensors (S1, S2) for generating detection signals (SR) representative of a distance of a mass (M) relative to the frame (10); a control unit (40) for determining, as a function of the detection signals (SR), whether the mass (M) is at a distance from the frame (10) within a predetermined value range, and to adjust the operating conditions of the lawn mower (1) as a function of the detection signals (SR); a selection circuit (50) interposed between the control unit (40) and sensors (S1, S2) for selectively enabling a connection between each of the sensors (S1, S2) and an input of the control unit (40).