Riding Lawn Mower Motor Control for Stable Slope Steering
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Solution Overview
Problem
Riding lawn mowers face difficulties in maintaining stability and direction on sloping surfaces due to uneven gravitational forces and lack of traction, requiring users to manually compensate, which can be challenging and uncomfortable.
Innovation Solution
A control method for riding lawn mowers that includes a walking assembly with two second walking wheels and a walking motor control module, which calculates and adjusts target speeds to compensate for torque and maintain stability and flexibility in steering, using a target speed calculation unit, decoupling unit, and processing unit to generate target speeds for the walking motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high-flotation / low pressure tires are used to traverse steep slopes, then the ability to traverse slopes is improved, but the cost and size of the riding lawn mower increase
Solution Approach 1:
The patent changes the control parameters of the walking motors through electronic control. The control module adjusts the rotation speeds of left and right walking motors based on detected operating states, enabling the mower to adapt to sloping surfaces without physical modifications like special tires.
Solution Approach 2:
The patent replaces mechanical solutions (specialized tires) with an electronic control system. The walking motor control module uses sensors and control algorithms to adjust motor speeds electronically, substituting the need for mechanical adaptations like high-flotation tires.
2Ease of operation
If the caster wheel is forcibly steered by a steering power source on sloping surfaces, then the caster wheel orientation control is improved, but the driving complexity and required user skill increase
Solution Approach 1:
The system performs self-correction by automatically detecting its own operating state through sensors and adjusting the walking motor speeds accordingly. The control module compensates for slope effects without requiring user intervention or complex manual manipulation of operating members.
Solution Approach 2:
The patent implements a feedback control system where sensors detect the operating state (including slope conditions) and feed this information back to the walking motor control module, which then adjusts motor speeds to maintain proper orientation and traversal capability.
3Adaptability or versatility
If the caster wheel is rendered freely steerable by blocking power transmission, then the steering flexibility is improved, but the ability to prevent downward orientation on slopes worsens
Solution Approach 1:
The patent makes the steering system dynamic by allowing it to switch between free-steering and controlled modes. The walking motor control module can forcibly steer the caster wheel when needed (by unblocking power transmission) while maintaining the option for free steering during normal operation, adapting to different terrain conditions.
4Ease of operation
If roll angle correcting means is used to compensate for inclined downward force, then the correction for roll angle is improved, but the correction for other influencing factors such as frictional force deteriorates
Solution Approach 1:
The patent uses a comprehensive feedback control system that detects multiple parameters including roll angle, but also other operating conditions. The walking motor control module processes this feedback to adjust motor speeds in a way that compensates for various forces including friction, gravity, and terrain variations, not just roll angle.
Solution Approach 2:
The system changes multiple control parameters simultaneously, including motor speeds, torque, and rotation rates, based on detected operating conditions. This multi-parameter adjustment allows compensation for various influencing factors beyond just roll angle, such as frictional forces and slope variations.
Data Source
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AI summary
A riding lawn mower is provided including: a seat; a chassis; a walking assembly configured to drive the riding lawn mower to walk, the walking assembly includes at least one first walking wheel and two second walking wheels, a left walking motor and a right walking motor; a left operating member operable by the user to generate a left operational amount; a right operating member operable by the user to generate a right operational amount; a walking motor control module configured to receive at least one of the left operational amount or the right operational amount, and control at least one of the left walking motor or the right walking motor; wherein the walking motor control module includes a target speed calculation unit, the target speed calculation unit including: an input unit configured to generate a left reference speed and a right reference speed from at least one of the left operational amount or the right operational amount; a decoupling unit configured to generate a first velocity and a second velocity from the left reference speed and the right reference speed; a processing unit configured to independently obtain a first processed velocity from the first velocity and obtain a second processed velocity from the second velocity; and an output unit configured to generate a left target speed for the left walking motor or a right target speed for the right walking motor from the first processed velocity and the second processed velocity.