Wheel Loader Steering Feedback for Angular Velocity Limit Awareness

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Solution Overview

Problem

Operators of articulated work vehicles are not aware of the upper limit of the steering angular velocity, leading to unnecessary operation and muscle strain as they may attempt to operate the joystick beyond the restricted position.

Innovation Solution

A work vehicle system comprising a hydraulic actuator, pump, operation member, control valve, angular velocity sensing unit, and notification component, which notifies the operator when the steering angular velocity reaches a preset threshold value, preventing excessive operation and reducing muscle strain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the joystick lever is mechanically restricted to a specific angle range, then the pilot valve can adjust pilot pressure according to the deviation angle, but the operator cannot perceive when the steering angular velocity reaches its upper limit and may vainly operate the joystick beyond the restriction

Engineering Contradiction:
Improvejoystick operation rangeVSAvoidsteering angular velocity limit information
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent implements a feedback mechanism where a notification component (visual, auditory, or haptic) provides real-time information to the operator about the steering angular velocity status. When the detected steering angular velocity approaches or reaches the upper limit, the notification component activates to alert the operator, creating a closed-loop feedback system that resolves the information asymmetry between the mechanical restriction and the operator's perception

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The notification component acts as an intermediary between the steering system and the operator. It translates the mechanical state (steering angular velocity) into perceivable signals (visual, auditory, or haptic), bridging the gap between the physical restriction and the operator's awareness without requiring direct mechanical feedback to the joystick

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the operator continues to operate the joystick beyond the restricted position, then the operator maintains control input, but unnecessary muscle strain occurs due to vain operation

Engineering Contradiction:
Improvecontrol continuityVSAvoidoperator muscle strain
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The notification component provides continuous feedback about the steering angular velocity status, enabling the operator to adjust their control input accordingly. This feedback loop prevents the operator from applying unnecessary force to the joystick beyond the effective range, thereby reducing muscle strain while maintaining control continuity within the operational limits

Inventive Principle:
Principle #23Feedback

3Device complexity

If the steering angular velocity upper limit is not communicated to the operator, then the system maintains simple mechanical restriction, but the operator lacks awareness and continues unnecessary operation

Engineering Contradiction:
Improvemechanical restriction systemVSAvoidsteering velocity limit awareness
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The notification component serves as an intermediary that communicates the steering angular velocity limit information to the operator without fundamentally altering the simple mechanical restriction system. It adds an information layer that bridges the gap between the mechanical limit and operator awareness while maintaining the original mechanical system's simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces potential complex mechanical feedback mechanisms with an electronic/sensor-based detection system and notification system. Instead of using complex mechanical linkages to provide tactile feedback about velocity limits, the system uses sensors to detect steering angular velocity and electronic notification components to communicate the limit status to the operator

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system effectively informs operators of the steering angular velocity limit, reducing unnecessary operation and minimizing physical effort by providing timely notifications through vibrations, lights, or sounds.

Implementation Method 1

A hydraulic actuator changes a steering angle on the basis of supplied fluid, and a hydraulic pump supplies the fluid

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

the notification component notifies the operator that the corresponding value has reached a threshold value preset on the basis of the upper limit of the steering angular velocity

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3412538B1Work vehicle and control method for work vehicle
Publication Date: 2023.05.31 KOMATSU LTD
  • EP3412538B1 patent drawingFigure 1
  • EP3412538B1 patent drawingFigure 2
  • EP3412538B1 patent drawingFigure 3

AI summary

A wheel loader (1) comprises steering cylinders (21 and 22), a steering pump (31a), a joystick lever (24), a pilot valve (42), an angular velocity corresponding value sensing unit (27), a notification component (29), and a controller (28). The pilot valve (42) controls the flow of fluid supplied from the steering pump (31a) to the steering cylinders (21 and 22) on the basis of how much the joystick lever (24) is operated. The angular velocity corresponding value sensing unit (27) senses a corresponding value that corresponds to the steering angular velocity that is changed on the basis of the fluid flow rate. The notification component (29) notifies the operator that the corresponding value has reached a threshold value preset on the basis of the upper limit of the steering angular velocity. When the controller (28) senses that the corresponding value has reached the threshold value, the controller (28) makes the notification component (29) give a notification.