Vehicle Control Device Uphill Backward Movement Suppression

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Solution Overview

Problem

Existing vehicle control systems fail to reliably prevent backward movement on uphill roads, leading to discomfort for occupants due to potential slipping or rolling, as they often rely solely on increasing braking force, which can result in excessive deceleration or insufficient acceleration.

Innovation Solution

A vehicle control device that adjusts both driving and braking forces to ensure their sum exceeds the gravitational force acting on the vehicle, thereby preventing backward movement by balancing forces and minimizing response delays in actuators, while also transitioning smoothly between deceleration and acceleration states to maintain fuel efficiency and followability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If only braking force is increased to prevent backward movement, then the vehicle can be restrained from slipping backward, but excessive deceleration force is applied to the vehicle causing discomfort to occupants

Engineering Contradiction:
Improvebackward movement suppressionVSAvoidexcessive deceleration force
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the total force requirement into two distinct components: driving force (Fd) and braking force (B). Instead of relying solely on braking force, the control unit calculates and applies both forces separately. The driving force is increased to counteract gravity's component along the slope, while the braking force is adjusted to prevent backward movement. This segmentation allows the system to achieve reliable backward movement suppression while distributing the force application to avoid excessive deceleration that would cause occupant discomfort.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent dynamically changes the parameters of both driving force and braking force based on real-time vehicle conditions. The control unit continuously monitors vehicle speed, acceleration, and slope angle, then adjusts Fd and B accordingly. By changing these parameters adaptively rather than relying on fixed braking-only control, the system achieves reliable backward movement prevention while optimizing the force distribution to minimize uncomfortable deceleration effects on occupants.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If braking force is increased to suppress backward movement, then the vehicle can be held stationary, but the deceleration may become insufficient or excessive affecting control precision

Engineering Contradiction:
Improvebackward movement suppressionVSAvoiddeceleration control precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback control mechanism where the control unit continuously monitors actual vehicle acceleration and speed, compares them with target values, and adjusts the driving force (Fd) and braking force (B) accordingly. This feedback loop ensures that the combined force application achieves the desired deceleration precision. By using feedback to coordinate both driving and braking forces, the system achieves reliable backward movement suppression while maintaining precise control over the deceleration process, avoiding both insufficient and excessive deceleration.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control unit dynamically adjusts the parameters of driving force and braking force based on real-time feedback from vehicle sensors. By changing these parameters adaptively according to actual vehicle conditions, the system achieves both reliable backward movement suppression and precise deceleration control, resolving the contradiction between force magnitude and control precision.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the vehicle stops on an uphill road without force correction, then the stopping is simple, but the vehicle may move backward after stopping due to gravity

Engineering Contradiction:
Improvestopping operationVSAvoidpost-stop stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by increasing the driving force (Fd) before the vehicle comes to a complete stop. The control unit detects deceleration and proactively adjusts Fd and B to counteract the component of gravity acting along the slope. This preliminary force adjustment ensures that when the vehicle stops, the forces are already balanced to prevent backward movement. The preliminary action maintains simple stopping operation while ensuring post-stop stability on uphill roads.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If response delay of braking actuator is considered, then the control is more accurate, but the vehicle may already have started moving backward by the time braking force is applied

Engineering Contradiction:
Improvebackward movement preventionVSAvoidactuator response time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent addresses actuator response delay by implementing preliminary action - increasing the driving force (Fd) in advance before the vehicle actually stops. The control unit detects deceleration and proactively adjusts both Fd and B to counteract gravity's component along the slope. This preliminary force adjustment ensures that when the braking actuator finally responds, the vehicle is already in a force-balanced state, preventing backward movement. This approach compensates for response time loss while maintaining reliable backward movement prevention.

Inventive Principle:
Principle #10Preliminary action

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

Effectively suppresses vehicle backward movement on uphill roads by balancing driving and braking forces, ensuring stable stopping and smooth transitions, thus enhancing occupant comfort and reducing fuel consumption.

Implementation Method 1

the processor corrects the required driving force and the required braking force so as to increase the required driving force and the required braking force such that a sum of a magnitude of the required driving force and a magnitude of the required braking force is equal to or larger than a magnitude of a component of the gravity acting on the vehicle in the movement direction of the vehicle

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3686070B1Vehicle control device
Publication Date: 2023.06.14 TOYOTA JIDOSHA KK
  • EP3686070B1 patent drawingFigure 1~2
  • EP3686070B1 patent drawingFigure 3~4
  • EP3686070B1 patent drawingFigure 5~6

AI summary

A vehicle control device is mounted on a vehicle including a driving actuator configured to apply a driving force and a braking actuator configured to apply a braking force. The vehicle control device includes a processor (21). The processor (21) is configured to correct, when a predetermined condition including at least that the vehicle is decelerating is satisfied, the required driving force and the required braking force so as to increase the required driving force and the required braking force such that a sum of a magnitude of the required driving force and a magnitude of the required braking force is equal to or larger than a magnitude of the component of the gravity acting on the vehicle in the movement direction of the vehicle.