Electric Lawn Mower Control System for Battery and Stall Management
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Solution Overview
Problem
Existing lawn mowers face challenges in extending the mowing time per battery charge, preventing blade motor stalling due to grass clogging, and maintaining consistent rotational speed and vehicle behavior.
Innovation Solution
An electric riding lawn mower equipped with a control system that includes first and second control units to manage the rotation of the working member (blades) and movement of the vehicle based on target state amounts, which can be instructed by passengers, operators, managers, or determined by the vehicle or control device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blade motor operates at high power to maintain consistent rotational speed, then the cutting performance is improved, but the battery charge depletes faster reducing mowing time
Solution Approach 1:
The blade motor rotational speed is made dynamically adjustable through multiple speed stages (first, second, third speeds) rather than operating at a fixed high speed. The control unit switches between different rotational speeds based on operating conditions, allowing the system to maintain reliability when needed while conserving energy during normal operation to extend mowing time.
2Productivity
If the blade motor operates continuously at high speed to prevent grass clogging, then the cutting efficiency is improved, but the motor is more prone to stalling
Solution Approach 1:
The system uses dynamic rotational speed adjustment with multiple predefined speeds. The control unit selects appropriate speed stages based on load conditions and operational requirements, preventing the motor from operating continuously at maximum speed which would increase stalling risk, while still maintaining high cutting efficiency when conditions permit.
3Adaptability or versatility
If the working member rotation and vehicle movement are controlled independently, then the control flexibility is improved, but the overall system coordination deteriorates
Solution Approach 1:
The control unit merges the control of the working member rotation and vehicle movement into a single integrated control system. By coordinating both functions through one control unit that receives inputs from multiple operators, the system maintains control flexibility while ensuring proper coordination between blade operation and vehicle motion, preventing conflicts and improving overall system stability.
Data Source
AI summary
A work vehicle, which includes drive wheels and blades serving as a working member, is equipped with a blade motor driver that controls rotation of the working member based on a target working member rotation state amount, and a drive wheel motor driver that controls movement of the work vehicle based on a target vehicle movement state amount, wherein the target working member rotation state amount and the target vehicle movement state amount are determined by a passenger or the like of the work vehicle, or alternatively, by a control device provided so as to be capable of communicating with the work vehicle.