Vehicle Steering Brake Control Without Outside-Wheel ASR Braking
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Solution Overview
Problem
Existing vehicle control systems face challenges in maintaining a strong steering effect while navigating tight bends, as the traction control system (ASR) may inadvertently increase bend radius by braking the outside wheel, which reduces the steering effect and causes wear-promoting brake engagements.
Innovation Solution
A method for operating a vehicle control system that integrates a drive motor, differential gear mechanism, and brake device, where the traction control system reduces drive slip by adjusting the drive motor's power rather than activating the brake on the outside wheel during steering brake function, thereby preserving the steering effect and avoiding unnecessary brake wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the traction control system brakes the outside wheel to reduce drive slip, then the drive slip is controlled to permissible levels, but the steering effect is reduced and the bend radius increases
Solution Approach 1:
The patent segments the drive axle into inside wheel and outside wheel, applying different control strategies to each. The inside wheel receives normal traction control braking when needed, while the outside wheel is excluded from braking during steering brake function activation, preserving the steering effect while maintaining drive slip control on the inside wheel.
Solution Approach 2:
The system dynamically switches between different control modes based on the activation state of the steering brake function. When the steering brake function is active, the control system adapts by dispensing with brake engagement for the outside wheel, allowing the system to transition from static traction control to dynamic steering-assisted operation.
2Ease of operation
If the steering brake function is activated to achieve tight bend radii, then the steering effect is enhanced, but the drive slip on the outside wheel increases to inadmissible levels
Solution Approach 1:
The control system segments the wheel control by identifying which wheel is the inside wheel and which is the outside wheel during steering brake function activation. It applies selective braking only to the inside wheel through the differential gear mechanism, while leaving the outside wheel unbraked to maintain the steering effect and prevent excessive drive slip.
Solution Approach 2:
The patent applies local quality by providing different brake control characteristics to different wheels based on their position during steering. The inside wheel receives braking intervention to control drive slip, while the outside wheel receives no braking to preserve the steering effect, creating localized control quality that addresses both contradictions.
3Reliability
If the brake device is engaged to control drive slip, then the drive slip is reduced to permissible levels, but wear on the brake system increases
Solution Approach 1:
The patent extracts the brake engagement action from the outside wheel during steering brake function activation. By removing the braking intervention from the outside wheel while maintaining it on the inside wheel, the system reduces unnecessary brake wear on the outside wheel while preserving essential drive slip control functionality.
Data Source
AI summary
A method for operating a vehicle-control-system, including: a) controlling, by a drive-control-system (DCS), a drive motor (DM) driving at least one driven-axle (HA) having first/second drive-wheels (DW), b) driving, via the DM, a differential-gear, between first/second DWs, c) controlling, by a brake-control-system (BCS), a brake-device (BD) having first/second brake-actuators (BA) for first/second DWs, d) providing a steering-brake-function (SBF), with which steering is provided by selectively controlling the first/second BAs of the HA, e) guiding, via a traction-control-system (ASR), an inadmissible drive-slip (DS) at the first/second DWs of the HA to a permissible DS by engaging: e1) in the drive-control of the DM, wherein the DM's drive-power is reduced, and/or by e2) in the BCS of the BD, wherein a DW having inadmissibly great DS, is selectively braked by the first/second DWs; f) dispensing with engagement in the BCS of the ASR BD, when the SBF/ASR is active/activated at the HA.