Adaptive Target Speed Control for Vehicle Braking on Slopes

Solution Overview

Problem

When driving on a dirt road with successive downhill and climbing slopes, the vehicle body speed significantly decreases upon transitioning from a downhill slope to a climbing road due to applied braking force, leading to excessive deceleration despite the driver's accelerator operation.

Innovation Solution

A driving assistance device with a braking control unit and a target speed determination unit that adjusts braking force by setting a lower-limit speed based on wheel speeds and road surface gradients, ensuring the target speed remains above a minimum threshold even during accelerator operations, thereby preventing excessive vehicle body speed reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the target speed is determined depending on the vehicle body speed on a downhill slope, then the braking force can be effectively controlled during downhill driving, but when transitioning to a climbing road the target speed becomes too low causing excessive deceleration

Engineering Contradiction:

Improvebraking force controlVSAvoidvehicle body speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent applies dynamics by making the target speed adaptive rather than fixed. The target speed determination unit dynamically adjusts the target speed based on the detected road surface gradient. When a climbing road is detected, the system increases the target speed above the current vehicle body speed, allowing the braking force to be reduced appropriately and preventing excessive deceleration during the transition from downhill to climbing terrain.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of target speed based on road gradient conditions. Instead of using a fixed target speed or solely relying on current vehicle speed, the system modifies the target speed parameter according to the detected road surface gradient. This parameter change ensures that when transitioning to a climbing road, the target speed is sufficiently high to maintain adequate vehicle body speed and reduce braking force appropriately.

Inventive Principle:

Principle #35Parameter changes

2Speed

If braking force is applied to maintain target speed on downhill, then speed control is achieved, but transitioning to climbing road causes considerable decrease in vehicle body speed even with accelerator operation

Engineering Contradiction:

Improvevehicle body speedVSAvoidaccelerator operation response

Core Design Contradiction:

SpeedVSEase of operation

Solution Approach 1:

The patent implements feedback by continuously monitoring the road surface gradient and using this information to adjust the target speed. The gradient detection unit provides feedback about the road condition, and the target speed determination unit uses this feedback to appropriately set the target speed. This feedback mechanism ensures that when the vehicle transitions to a climbing road, the system recognizes the change in gradient and adjusts the target speed accordingly, allowing the accelerator operation to have the intended effect of increasing vehicle body speed.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If the target speed is set low based on current vehicle speed, then braking control is precise on downhill, but the vehicle cannot maintain adequate speed when entering a climbing road

Engineering Contradiction:

Improvespeed control precisionVSAvoidvehicle body speed

Core Design Contradiction:

Manufacturing precisionVSSpeed

Solution Approach 1:

The patent applies dynamics by making the target speed adaptive rather than fixed. The target speed determination unit dynamically adjusts the target speed based on the detected road surface gradient. When a climbing road is detected, the system increases the target speed above the current vehicle body speed, allowing the braking force to be reduced appropriately and preventing excessive deceleration during the transition from downhill to climbing terrain.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of target speed based on road gradient conditions. Instead of using a fixed target speed or solely relying on current vehicle speed, the system modifies the target speed parameter according to the detected road surface gradient. This parameter change ensures that when transitioning to a climbing road, the target speed is sufficiently high to maintain adequate vehicle body speed and reduce braking force appropriately.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10286887B2Driving assistance device for vehicle

Publication Date: 2019.05.14 ADVICS CO LTD

AI summary

This driving assistance device includes a braking control unit and a target speed determination unit. The braking control unit executes driving assistance control for adjusting the braking force to be applied to a vehicle by actuating a brake actuator such that the vehicle body speed does not exceed a target speed. In cases where the accelerator pedal is being operated in a state where the braking control unit is executing the driving assistance control, the target speed determination unit determines the target speed depending on the larger value of either: the vehicle body speed that is correlated with at least one of the wheel speeds of the plurality of wheels provided to the vehicle; or the lower speed limit value that has been set.