Brake Actuator ECU Redundancy Using One Voltage Supply Level
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Solution Overview
Problem
Existing brake-by-wire systems in commercial vehicles lack adequate redundancy in electrical and communication interfaces, leading to potential loss of brake performance and stability in case of failures, and are hindered by the presence of pneumatic systems that occupy installation space.
Innovation Solution
An electronic control unit (ECU) with two electrical supply interfaces and two communication interfaces, operating on the same voltage level, ensures redundancy by splitting power demands across main and secondary supply lines and maintaining redundant CAN communication, using power and safety switches to manage failures and protect against voltage fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant electrical supply interfaces are implemented at different voltage levels, then brake actuator reliability is improved, but the number of electrical connectors increases and installation space is insufficient
Solution Approach 1:
The patent applies universality by making both the main and secondary supply interfaces operate at the same voltage level (e.g., 24V), allowing them to be physically identical and interchangeable. This multi-functional design enables either interface to serve as the primary power source, reducing the need for different types of connectors and simplifying the electrical connection system while maintaining redundancy for reliable brake actuator operation
2Reliability
If pneumatic systems are retained for backup braking, then brake system safety is improved, but installation space in the cabin is occupied
Solution Approach 1:
The patent applies mechanics substitution by replacing the traditional pneumatic backup system with an electrical redundancy system. Instead of using compressed air and pneumatic components for backup braking, the system uses a second electrical supply interface at the same voltage level that can independently power the brake actuator, thereby eliminating the need for pneumatic tanks, compressors, and associated mechanical infrastructure in the cabin
3Reliability
If redundant communication interfaces are implemented, then vehicle stability and communication reliability are improved, but the complexity of the control system increases
Solution Approach 1:
The patent applies homogeneity by implementing both communication interfaces using the same CAN bus protocol and voltage level. This uniform approach allows the redundant communication paths to be physically and functionally identical, simplifying the control system architecture while ensuring that either communication path can maintain vehicle stability and brake actuator control without requiring complex protocol conversion or interface management
Data Source
Figure 1
AI summary
An electronic control unit (ECU) for an actuator of an electro-mechanical brake for a commercial or transport vehicle comprises two electrical supply interfaces which comprise a main supply interface which operates on a first voltage level U1, wherein the main supply interface is in electrical communication with a main supply line (MSL, 10), wherein the main supply line (MSL, 10) is configured to operate the brake actuator. The two electrical supply interfaces further comprise a secondary supply interface which operates on the first voltage level U1, wherein the secondary supply interface is in electrical communication with a secondary supply line (SSL). The main supply interface and supply line (MSL) have a first power capability P1, and the secondary supply interface and supply line (SSL) have a second power capability P2, wherein the sum of the two power capabilities P1, P2 is equal to or higher than the maximum power demand P0 required by the brake actuator. A power switch (PS1) connects the main supply line (MSL) with the secondary supply line (SSL) to ensure a power demand Pm required by the electric motor driving the brake actuator, wherein the power demand Pm is split between the main supply line (MSL) and the secondary supply line (SSL). The ECU further comprises two data communication interfaces which respectively are in data communication with two communication lines (CL1, CL2) which are configured to operate a CAN communication between the brake actuator and the vehicle. The two communication lines (CL1, CL2) are respectively connected to two CAN RX/TX circuits (CC1, CC2).