Zero Turn Radius Vehicle Asymmetric Wheel Steering Control

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Solution Overview

Problem

Existing zero turn radius vehicles face challenges in efficiently controlling steering, speed, and direction, particularly when navigating sloped or uneven terrain, due to limitations in power transfer mechanisms and wheel configurations.

Innovation Solution

A utility vehicle design featuring a pair of driven rear wheels, a steerable front wheel, and a non-steerable caster wheel, with a controller and electric actuators that coordinate the power transfer mechanisms and wheel orientations based on operator input, enhancing control and stability across varying terrains.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional two-wheel steering configuration is used, then the vehicle structure is simple, but the vehicle cannot achieve zero turn radius and has poor maneuverability on sloped terrain

Engineering Contradiction:

ImprovemaneuverabilityVSAvoidwheel configuration

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by configuring one front wheel as steerable and the other as a non-steerable caster wheel, rather than using symmetric two-wheel steering. This asymmetric configuration enables zero turn radius capability while maintaining structural simplicity, resolving the contradiction between maneuverability and device complexity.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent implements dynamic control through independent actuation of the steerable wheel and differential speed control of the rear wheels. The controller dynamically adjusts wheel orientations and speeds based on operator input, enabling seamless transitions between forward and reverse travel on sloped terrain, thereby improving ease of operation.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If electric actuators are used for wheel steering, then steering precision and control are improved, but energy consumption increases

Engineering Contradiction:

Improvesteering controlVSAvoidenergy consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent replaces traditional mechanical steering linkages with electric actuators that receive signals from the controller. This substitution provides more precise steering control and enables coordinated operation with the differential drive system, improving ease of operation despite increased energy consumption from the electric motors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If differential speed control of rear wheels is implemented, then the vehicle can navigate sloped terrain effectively, but the power transfer mechanism complexity increases

Engineering Contradiction:

Improveterrain adaptabilityVSAvoidpower transfer mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the power transfer system by providing independent speed control for each rear wheel through separate electric motors. This segmentation enables differential speed control that adapts to sloped terrain, with each wheel independently adjusted to maintain traction and prevent slipping, thereby improving terrain adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The controller implements feedback control by monitoring wheel position, speed, and terrain conditions, then dynamically adjusting the speed of each rear wheel accordingly. This feedback mechanism enables effective navigation of sloped terrain while managing the complexity of the power transfer system through intelligent control algorithms.

Inventive Principle:

Principle #23Feedback

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

The vehicle achieves improved control and stability by coordinating the speed and direction of rear wheels with the steering of the front wheel, reducing scuffing and stress on the frame, and allowing seamless transitions between forward and reverse travel on sloped or uneven surfaces.

Implementation Method 1

an electric actuator connected to the controller and providing a steering force for steering the first steerable wheel

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

a second non-steerable caster wheel located adjacent the front of the vehicle frame, on a second side of the vehicle frame opposite the first side

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS10829150B1Zero turn radius vehicle with single steered wheel

Publication Date: 2020.11.10 HYDRO GEAR LP

AI summary

A zero turn radius vehicle with a single steered wheel may include a pair of power transfer mechanisms driving a pair of wheels, an operator control mechanism for controlling the steering, speed and direction of the vehicle and a controller in communication with the control mechanism. A steerable wheel is located adjacent the front of the vehicle frame, on a first side of the vehicle frame and an electric actuator is connected to the controller for steering the front steerable wheel. A second, non-steerable front caster wheel is located on a second side of the vehicle frame. A damper is connected to the non-steered wheel to dampen rotation of the non-steered wheel about a non-steered wheel pivot axis The controller controls the pair of power transfer mechanisms and the electric actuator based on operator input.