Industrial Vehicle Drive Control for Temporary Driver Unseating

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Solution Overview

Problem

Existing industrial vehicle control systems interrupt driving force transmission when a driver becomes temporarily unseated, leading to reduced driving comfort and operational feeling changes.

Innovation Solution

The system introduces operation modes such as the limit mode and interruption mode to manage driving force transmission based on the duration of the unseated state, ensuring smooth transitions back to normal operation when the driver reseats.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the controller stops energizing the solenoid valve after a predetermined delay time when the driver is unseated, then safety is improved by preventing unintended vehicle movement, but driving comfort deteriorates due to interruption of driving force transmission

Engineering Contradiction:
ImprovesafetyVSAvoiddriving comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies dynamics by making the control system adaptable to different driver states. The controller dynamically adjusts the solenoid valve energizing state based on real-time detection of driver seating status and operation lever position, transitioning between different control modes (normal mode, unseated state mode, neutral state mode) to optimize both safety and driving comfort under varying conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the control parameter (solenoid valve energizing state) based on detected driver state and operation lever position. When the driver is unseated and the operation lever is in neutral, the controller maintains solenoid valve energizing to preserve driving force transmission, whereas in other unseated conditions it stops energizing to ensure safety.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the transmission of driving force is interrupted when the driver is unseated for a prolonged period, then safety is improved by preventing unintended vehicle movement, but operational feeling changes and driving comfort is reduced

Engineering Contradiction:
ImprovesafetyVSAvoidchange in operational feeling
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The controller dynamically determines the energizing state of the solenoid valve based on the driver's unseated state and the position of the operation lever. When the operation lever is in the neutral state, the controller maintains energizing to prevent operational feeling changes, while in other positions it stops energizing to ensure safety.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control parameter (solenoid valve energizing state) is changed based on the combination of driver state and operation lever position. This selective parameter change ensures that driving force transmission is maintained only when safe (neutral position), thereby preventing unwanted vehicle movement while avoiding operational feeling changes during legitimate neutral operations.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the controller maintains energizing of the solenoid valve during temporary unseating, then driving comfort is improved by maintaining smooth driving force transmission, but safety risk increases due to potential unintended vehicle movement

Engineering Contradiction:
Improvedriving comfortVSAvoidsafety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The controller dynamically adjusts the solenoid valve energizing state based on real-time detection of driver seating status and operation lever position. This dynamic control maintains energizing during temporary unseating only when the operation lever is in neutral, thereby improving driving comfort while preventing unintended vehicle movement in other positions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control parameter (solenoid valve energizing state) is selectively maintained or changed based on the operation lever position during unseated states. When the lever is in neutral, the parameter remains unchanged to maintain driving comfort; in other positions, the parameter changes to stop energizing and ensure safety.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4201774B1Industrial vehicle and method for controlling industrial vehicle
Publication Date: 2025.06.18 TOYOTA INDUSTRIES CORP
  • EP4201774B1 patent drawingFigure 1
  • EP4201774B1 patent drawingFigure 2
  • EP4201774B1 patent drawingFigure 3~5

AI summary

An industrial vehicle includes an engine, a driven wheel, a driver's seat, on which a driver is seated, a driver detecting unit, and a controller. The controller sets an operation mode of operation modes. The operation modes include a normal mode, a limit mode that limits a driving force of the engine, and an interruption mode that interrupts a transmission of the driving force to the driven wheel by a driving force transmitting mechanism (60). The controller performs a process that sets the operation mode to the limit mode when an unseated state duration is determined to be shorter than or equal to an unseated state determination time. The controller also performs a process that sets the operation mode to the interruption mode when the unseated state duration is determined to be longer than the unseated state determination time.