Lawn Mower Torque Control for Grass Protection
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Solution Overview
Problem
Lawn mowers often skid and bruise grass when encountering obstacles due to the drive wheels continuing to rotate despite collision detection failures, resulting in damage to the grass.
Innovation Solution
A lawn mower with a control apparatus that sets torque thresholds to prevent the drive wheels from rotating during collisions, using a first torque threshold for startup protection and a second torque threshold to manage resistance during normal operation, ensuring the drive wheels do not overcome obstacle resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drive motor maintains high torque output to ensure sufficient cutting power, then grass cutting efficiency is improved, but the drive wheels will skid and bruise grass when encountering obstacles
Solution Approach 1:
The control apparatus dynamically adjusts the torque output parameter of the drive motor based on real-time detection of wheel rotation status. When obstacle detection is triggered, the system changes the torque parameter from high (cutting mode) to limited (prevention mode), resolving the contradiction between cutting efficiency and grass protection
Solution Approach 2:
The system implements a feedback control loop where the control apparatus continuously monitors wheel rotation through sensors and adjusts motor torque accordingly. When obstacle detection indicates wheel skidding, the feedback signal triggers torque reduction to prevent grass bruising while maintaining cutting capability when wheels rotate normally
2Ease of operation
If the drive motor maintains high torque to overcome resistance during startup, then the lawn mower can start on uneven terrain, but the drive wheels will skid on obstacles during collision
Solution Approach 1:
The control apparatus implements dynamic torque management that adapts to different operational phases. During startup, high torque is permitted to overcome terrain resistance, but upon obstacle detection during operation, the system dynamically switches to torque limitation mode to prevent skidding, resolving the contradiction between startup capability and collision response reliability
Solution Approach 2:
The control apparatus is preset with torque threshold parameters that define safe operating limits. When obstacle detection is triggered, the preliminary configured torque limits are immediately applied to prevent skidding, ensuring reliable collision response while maintaining startup performance through proper parameter configuration
Data Source
AI summary
A lawn mower including a housing; a walking mechanism, supporting the housing and driving the housing to move, and including at least one drive wheel; at least one motor to drive the at least one drive wheel to rotate; and a control apparatus, preset with a first and a second torque threshold. And when the motor is switched from a stopped state to a running state, the control apparatus controls a difference between a maximum operating output torque of the motor and the first threshold to be within a predetermined range, when the motor is in the running state, the control apparatus controls an operating output torque of the at least one motor to at most increase to the second threshold, the first threshold is less than or equal to a maximum output torque of the motor, and the second threshold is less than the first threshold.