Drive-By-Wire Mower Control for Straight Tracking and ZTR Maneuvers

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Solution Overview

Problem

Existing self-propelled vehicles, particularly zero-turn-radius (ZTR) lawnmowers, face challenges in maintaining a straight path of travel due to the complexity of mechanical linkage controls, which can be difficult for novice operators and lead to operator fatigue and inadvertent deviations from a straight path, especially on uneven terrain.

Innovation Solution

A drive-by-wire system that includes a controller to manage motor operations based on operator inputs, allowing for a first mode that mimics conventional mechanical linkage and a second mode that simplifies control for precise straight-line tracking and zero-turn-radius maneuvers, reducing operator effort and enhancing comfort and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If mechanical linkage controls are used in ZTR lawnmowers, then the vehicle can achieve zero-turn-radius maneuvers, but the control complexity increases and operator fatigue increases

Engineering Contradiction:

Improvezero-turn-radius maneuverabilityVSAvoidoperator control difficulty

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent replaces the traditional mechanical linkage control system with an electronic control system. The operator inputs (control levers) are no longer mechanically connected to the drive motors through linkages, but instead send electronic signals to a controller that manages motor operations. This substitution eliminates the complexity of mechanical linkages while maintaining the zero-turn-radius capability, directly resolving the contradiction between maneuverability and ease of operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If mechanical linkage controls are used, then direct control of each motor is possible, but operator fatigue and inadvertent deviations from straight path occur

Engineering Contradiction:

Improvedirect motor controlVSAvoidstraight path maintenance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent incorporates feedback mechanisms where the controller receives signals from operator inputs and continuously adjusts motor operations based on the desired path. The electronic control system can detect deviations and make corrections, providing feedback loops that maintain straight path travel more reliably than mechanical linkages alone. This feedback capability resolves the contradiction by maintaining direct control while improving path accuracy.

Inventive Principle:

Principle #23Feedback

3Device complexity

If conventional mechanical linkage is used, then simple control structure is maintained, but operator comfort and precision in straight-line tracking deteriorate

Engineering Contradiction:

Improvecontrol structure simplicityVSAvoidstraight-line tracking precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the simple but imprecise mechanical linkage structure with an electronic control system that provides superior straight-line tracking precision. The electronic sensors, controllers, and actuators enable more precise control of motor operations, allowing the lawnmower to maintain straight paths with greater accuracy despite the increased electronic system complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Speed

If mechanical linkage controls are used, then direct control response is achieved, but operator effort and fatigue increase

Engineering Contradiction:

Improvecontrol response speedVSAvoidoperator effort

Core Design Contradiction:

SpeedVSEase of operation

Solution Approach 1:

The patent replaces mechanical linkage control with an electronic control system that reduces operator effort while maintaining rapid response. The electronic sensors detect operator input instantly, and the controller processes signals and adjusts motor operations electronically, eliminating the physical effort required to manipulate mechanical linkages. This substitution maintains fast control response speed while significantly reducing operator fatigue.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12477975B2Drive-by-wire system for vehicle, zero-turn-radius lawnmower including same, and drive-by-wire system for lawnmower

Publication Date: 2025.11.25 HONDA MOTOR CO LTD

AI summary

A drive-by-wire system can include pair of inputs and a controller configured to process signals from the inputs in a first mode and process the same signals differently in a second mode. The controller can be configured to, in the first mode, drive a first motor at a speed and direction that corresponds to the position of the first input and drive a second motor at a speed and direction that corresponds to the position of the second input and, in the second mode, drive the first motor and the second motor in the same direction and at the same speed using the first drive signal when the controller receives a second neutral signal from the second input, and drive the first motor and the second motor at different speeds and/or directions when the controller receives the first drive signal and the second drive signal.