Optical Sensor Anticipative Electric Mower Control
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Solution Overview
Problem
Existing anticipative mowers require operators to constantly adjust speed based on grass height and density, leading to inefficient mowing performance, reduced operator comfort, limited battery life, and increased noise levels.
Innovation Solution
An electric mower equipped with an optical sensor oriented towards the ground to predict grass height and density, coupled with an electronic control unit that adjusts the cutting blade's rotation speed based on the sensor data and forward speed, allowing for optimized mowing performance while minimizing energy consumption and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the operator constantly adjusts the forward speed based on grass height and density, then the mowing performance is optimized, but the operator comfort deteriorates and the operation becomes complex
Solution Approach 1:
The optical sensor performs preliminary detection of grass height and density before the cutting blade reaches the vegetation. This advance information allows the control unit to pre-adjust the blade rotation speed, eliminating the need for constant operator intervention and manual speed adjustments during mowing operations.
Solution Approach 2:
The system implements a feedback loop where the optical sensor continuously monitors vegetation parameters, the control unit processes this information, and the blade speed is automatically adjusted in real-time. This closed-loop control maintains optimal mowing performance while freeing the operator from constant manual adjustments.
2Productivity
If the blade rotation speed is increased to handle dense or tall grass, then the mowing performance improves, but the energy consumption increases and battery life decreases
Solution Approach 1:
The blade rotation speed is made dynamic rather than fixed. The control unit continuously adjusts the blade speed based on real-time optical sensor data about grass height and density. The blade operates at high speed only when vegetation requires it, and at lower speeds when the terrain is clear, optimizing the balance between performance and energy consumption.
Solution Approach 2:
The system changes the operational parameters (blade rotation speed) based on detected conditions. The control unit modifies the motor power delivery to match the actual mowing requirements, preventing unnecessary energy consumption during low-vegetation periods while ensuring adequate power delivery when dense or tall grass is detected.
3Productivity
If the blade rotation speed is increased to cut through dense vegetation, then the mowing performance improves, but the noise level increases
Solution Approach 1:
The optical sensor detects dense vegetation in advance, allowing the control unit to gradually increase blade speed before encountering heavy vegetation. This prevents sudden high-speed operation and associated noise spikes, while still ensuring the blade has sufficient speed to effectively cut through the vegetation when reached.
Solution Approach 2:
The system applies high blade speed periodically only when vegetation density requires it, rather than maintaining high speed continuously. The control unit modulates the blade speed based on the periodic detection of vegetation zones, reducing overall noise exposure while maintaining cutting effectiveness during necessary high-speed intervals.
4Loss of information
If the optical sensor is positioned upstream of the cutting blade, then predictive detection of grass parameters is enabled, but the device complexity increases
Solution Approach 1:
The optical sensor serves multiple functions: it detects grass height, determines vegetation density, and provides predictive information for control adjustments. This multi-functionality justifies the added component, as a single sensor replaces what would otherwise require multiple separate detection systems or manual assessment methods.
Solution Approach 2:
The optical sensor acts as an intermediary between the vegetation and the control system. It converts physical vegetation characteristics into electrical signals that the control unit can process, enabling automatic speed adjustment without requiring direct mechanical interaction between the blade and vegetation detection mechanisms.
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
The solution enables consistent mowing at a constant speed, improving performance and comfort, extending battery life, and reducing noise by dynamically adjusting the blade's rotation speed according to the vegetation density and height, thus optimizing energy use and reducing acoustic nuisance.
Implementation Method 1
at least one optical sensor placed upstream of the cutting blade... configured to deliver, during the forward movement of the mower, at least one usable predictive signal to determine, upon processing, at least either a height of plants to cut, or a density of plants to cut
Data Source
AI summary
An electric mower of the battery-operated type has at least one cutting blade, an electric motor for driving the cutting blade, and an electronic piloting unit for the electric motor. At least one optical sensor is deposited upstream of the cutting blade. The optical sensor is configured to deliver; as the mower advances, at least one predictive signal of a quantity of plants to be cut. The electronic piloting unit is configured to establish an optimum rotation speed of the drive motor of the cutting blade, of said predictive signal of the optical sensor, and of a speed of advance of the mower. The method and apparatus are applicable at least to walk-behind mowers.