Riding Lawn Mower Motor Control for Fast Torque Response
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Solution Overview
Problem
Riding lawn mowers experience slow torque response speed in their motors, leading to poor user experience and safety risks due to hysteresis and misjudgment by operators, especially during climbing processes where the mower may slip backward.
Innovation Solution
The implementation of a control system that includes a rack, seat, wheel set, running motor, battery packs, operating assembly, driver circuit, detection devices, and a control module to dynamically adjust currents applied to the motor windings based on real-time rotational speed and rotor position, ensuring the motor reaches the target torque within a preset time, typically less than 100 ms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional motor control method is used, then device complexity is reduced, but torque response speed becomes slow
Solution Approach 1:
The patent implements a closed-loop control system that continuously detects actual motor speed and position, compares them with target values, and adjusts control signals accordingly. This feedback mechanism enables the motor to rapidly respond to speed changes while maintaining control precision, resolving the contradiction between fast response and controlled complexity.
Solution Approach 2:
The control system dynamically adjusts control parameters based on real-time motor state and operating conditions. By making the control system adaptive and variable rather than fixed, the motor can achieve rapid torque response across different operating points without requiring excessive system complexity.
2Productivity
If motor torque response speed is increased, then productivity is improved, but reliability may deteriorate due to potential instability
Solution Approach 1:
The closed-loop control continuously monitors actual motor performance and makes real-time corrections, ensuring that rapid torque response does not compromise stability. This feedback mechanism maintains reliability by preventing overshoot and oscillation even during fast response transitions.
Solution Approach 2:
The control system performs preliminary calculations and preparations for upcoming speed changes, smoothing transitions and preventing abrupt torque changes that could cause instability. This proactive approach maintains system reliability while achieving fast response times.
3Measurement precision
If data refresh rate is increased, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The data refresh rate is dynamically adjusted based on operating conditions. During high-speed changes or critical operations, the refresh rate increases to improve measurement precision. During steady-state operation, the refresh rate decreases to conserve energy, thus resolving the contradiction between precision and energy consumption.
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 significantly improves the motor's response speed, enhancing user experience and safety by allowing the riding lawn mower to reach target rotational and torque settings quickly and stably, reducing the risk of slipping during climbs.
Implementation Method 1
The running motor is configured to drive the at least two driving wheels to rotate and includes a stator and a rotor
Implementation Method 2
The driver circuit is electrically connected to the running motor and configured to distribute electric power of the plurality of battery packs to multiphase windings on the stator in a preset logical relationship so that the driver motor is capable of generating continuous torque
Data Source
AI summary
A riding lawn mower includes a running assembly, a power output assembly, a power supply device, a driver circuit, an operating device, and a control module. The running assembly includes running wheels and a first motor for driving the running wheels. The operating device is configured to set at least one of target torque or a target rotational speed of the first motor. The control module is configured to output a control signal to the driver circuit to make an input current or an input voltage of the first motor vary with a rotor position of the first motor and make an actual torque of the first motor reach or basically reach the target torque within a preset time.