Braking Device with Dual Control Circuits for Autonomous Vehicle Redundancy

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Solution Overview

Problem

Existing electronic brake systems with priority electro-pneumatic circuits and subordinate purely pneumatic restraint circuits are not suitable for vehicles in autonomous driving mode, as they lack the capability for full anti-lock braking function (ABS), driving dynamics control, and traction control, and require costly modifications to existing components for redundancy.

Innovation Solution

A fluid-actuated and at least partially electronic braking device with two electrically controllable pressure control valves in each brake circuit, where a secondary control device takes over in case of failure to provide ABS, ESP, and traction control functionality, using conventional pressure control modules and maintaining pneumatic backup systems for redundancy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If priority electro-pneumatic brake circuits with subordinate purely pneumatic restraint circuits are used, then brake control functionality is provided, but full ABS, ESP, and traction control functionality is lost and costly component modifications are required

Engineering Contradiction:
Improvebrake control functionalityVSAvoidABS and ESP functionality
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The brake control system is segmented into two independent control circuits: a primary electro-pneumatic control circuit for normal operation and a secondary purely pneumatic control circuit for backup. Each circuit has its own control unit and can operate independently, allowing the system to maintain ABS and ESP functionality even when one circuit fails.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the control mode parameter from electro-pneumatic to purely pneumatic when switching between primary and secondary circuits. The secondary control unit uses pneumatic signals instead of electrical signals to control the brake cylinders, enabling full ABS and ESP functionality without requiring electrical components.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional pressure control modules are used without modifications, then cost is reduced, but full ABS and ESP functionality for autonomous vehicles is not achieved

Engineering Contradiction:
ImprovecostVSAvoidautonomous driving compatibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The control system is divided into primary electro-pneumatic control and secondary purely pneumatic control. The secondary control unit uses standard pneumatic components that are already present in conventional brake systems, avoiding the need for expensive modifications while enabling autonomous driving compatibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The secondary control unit utilizes existing pneumatic components and pressure control modules already present in the brake system, making them serve a dual purpose: normal brake control and autonomous driving backup control, thereby eliminating the need for additional expensive components.

Inventive Principle:
Principle #25Self-service

3Reliability

If a secondary purely pneumatic control circuit is added for redundancy, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesystem redundancyVSAvoidcontrol circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The secondary purely pneumatic control circuit is designed to perform multiple functions: it serves as a backup control circuit for reliability, provides full ABS and ESP functionality, and can operate independently without requiring additional complex components. The pneumatic control unit integrates multiple control functions into a single device.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses pneumatic pressure control instead of electrical control for the secondary circuit. By utilizing pneumatic signals and pressure control, the system achieves redundancy without requiring complex electrical wiring, sensors, and electronic control units, thereby reducing overall system complexity.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

Enables full ABS and ESP functionality in autonomous vehicles without the need for expensive component modifications, ensuring reliable brake control and compatibility with autonomous driving modes using standard components.

Implementation Method 1

two electrically controllable pressure control valves in each brake circuit

Methodology Applied
Scientific EffectPneumatic pressure control: Pressure Gradient

Implementation Method 2

Braking device activated by compressing a medium

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

output signals from wheel speed sensors

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3421309B1Braking device activated by compressing a medium and at least partially electronic
Publication Date: 2021.11.03 MAN TRUCK & BUS SE
  • EP3421309B1 patent drawingFigure 1
  • EP3421309B1 patent drawingFigure 2A~2D

AI summary

The invention relates to a pressure-medium-actuated and at least partially electronic braking device for a vehicle with at least two axles, in particular for a commercial vehicle. The braking device comprises a first brake circuit (10) with at least one first pressure control module (11) for controlling the brake pressures in the wheel brakes of the first axle (2) and a second brake circuit (20) with at least one second pressure control module (21) for controlling the brake pressures in the wheel brakes of a second axle (3). The braking device further comprises a brake pressure sensor (6) for generating an electrical control signal and a first control unit (100) configured to generate brake pressure specifications for the first and the second pressure control modules (11, 21) depending on the control signal generated by the brake pressure sensor (6) and on output signals from wheel speed sensors (13, 23).In this system, two pressure control valves (12, 22) are arranged in each of the first and/or second brake circuits, each assigned to a wheel of an axle and electrically controllable. Furthermore, the brake system includes a second control unit (200) configured to actuate the two pressure control valves (12) only in the event of a failure of the first control unit (100), based on output signals from the wheel speed sensors (13), to implement an anti-lock braking system (ABS), electronic stability program (ESP), and/or traction control. With this approach, known brake systems of this type can be extended, simply by adding known, standard components, to provide an electrical backup system to safeguard against failures of the first control unit, thereby ensuring a fully functional anti-lock braking system (ABS), ESP, and/or traction control.