Electric Work Vehicle Turn Response Enhancement

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Solution Overview

Problem

Existing electric work vehicles face challenges in achieving both steering stability during straight traveling and agile turning ability, with current control methods resulting in sluggish turning operations and potential vehicle deviation during straight travel.

Innovation Solution

The electric work vehicle incorporates a turn response enhancement unit that provides additional control to the traveling motor control unit, allowing for differentiated speed or torque characteristics during turning by calculating and applying necessary current or torque adjustments based on steering signals, angular speed, and angular acceleration, enhancing turning response and sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If control sensitivity is raised to improve turning response, then turning ability is improved, but vehicle body deviation occurs during straight traveling

Engineering Contradiction:
Improveturning response speedVSAvoidvehicle body stability during straight traveling
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The control system dynamically adjusts control parameters based on the vehicle's operating state. During turning, the system increases control sensitivity to improve turning response, while during straight traveling, it reduces control sensitivity to maintain vehicle body stability. This dynamic adaptation resolves the contradiction by making the control characteristics variable rather than fixed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes control parameters (such as gain values in the PID controller) based on the detected vehicle state. When turning is detected, parameters are adjusted to enhance turning response; when straight traveling is detected, parameters are adjusted to prevent vehicle body deviation. This parameter adaptation allows the system to optimize performance for different operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional PID control is used for motor speed control, then basic traveling control is achieved, but turning operations feel sluggish

Engineering Contradiction:
Improveturning operation responsivenessVSAvoidturning execution time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system performs preliminary detection of turning intent through the steering sensor before the actual turning action begins. By detecting the steering input early, the control system can prepare and apply enhanced control parameters in advance, reducing the perceived sluggishness and加快 the turning response without causing instability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention introduces an intermediate control layer between the steering input and the motor control. This intermediate layer includes a state detection unit and a parameter adjustment unit that process the steering signal and adjust control parameters before they reach the PID controllers. This intermediary structure enables enhanced turning response while maintaining basic PID control functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3498573B1Electric work vehicle
Publication Date: 2021.04.28 KUBOTA CORP
  • EP3498573B1 patent drawingFigure 1
  • EP3498573B1 patent drawingFigure 2
  • EP3498573B1 patent drawingFigure 3

AI summary

An electric work vehicle of the present invention includes a left drive wheel (2a) and a right drive wheel (2b) that are supported by a vehicle body, a left motor (81) that drives the left drive wheel (2a) and a right motor (82) that drives the right drive wheel (2b), a traveling motor control unit that controls the left motor (81) and the right motor (82) independently based on steering signals from a steering unit (15), and a turn response enhancement unit. The turn response enhancement unit gives, to the traveling motor control unit, additional control amounts for the left motor (81) and the right motor (82) so as to improve turning response during turning of the vehicle body.