Redundant Actuator Decoupling to Block Compensation Currents
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Solution Overview
Problem
In autonomous driving systems, compensation currents between redundant control units can cause damage and loss of redundancy due to voltage and ground offsets, leading to unintended current flows and faulty electronic control unit operations.
Innovation Solution
The implementation of semiconductor switching modules or diodes in the positive and ground paths to prevent compensation currents, ensuring safe operation even without galvanic isolation, and maintaining redundancy by blocking unwanted current flows between control units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two independently voltage-supplied control units share common solenoid valves without galvanic isolation, then system complexity is reduced and ease of operation is improved, but compensation currents occur due to voltage and ground offsets causing damage and loss of redundancy
Solution Approach 1:
The patent introduces an intermediary device (isolation barrier or DC-DC converter) between the two control units that shares the solenoid valves. This intermediary blocks compensation currents while allowing controlled current flow to the solenoid valves, thus maintaining redundancy without requiring full galvanic isolation of all components.
Solution Approach 2:
The patent segments the electrical paths by introducing separate controlled current paths for each control unit to the shared solenoid valves. This segmentation prevents direct current circulation between the two voltage supplies while allowing independent control, thus eliminating compensation currents while maintaining system functionality.
2Reliability
If galvanic isolation is implemented between redundant control units to prevent compensation currents, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
Instead of full galvanic isolation, the patent segments the isolation requirement to only the critical path between the two control units' voltage supplies. The solenoid valve control paths remain shared but are protected by the segmentation of voltage reference paths, reducing complexity while maintaining protection.
Solution Approach 2:
The patent uses an intermediary isolation barrier or DC-DC converter specifically positioned to block compensation currents between the two independent voltage supplies, while allowing the solenoid valves to remain shared. This targeted intermediary approach provides necessary isolation without the complexity of complete galvanic isolation of all components.
3Object-affected harmful factors
If current blocking devices are added to prevent compensation currents, then protection is improved, but ease of operation and system simplicity deteriorate
Solution Approach 1:
The patent introduces current blocking devices as intermediaries in the voltage supply paths between the two control units. These devices automatically block compensation currents while transparently allowing normal operation during fault conditions, thus providing protection without requiring changes to operational procedures or increasing operational complexity.
Data Source
AI summary
A device for decoupling and/or protecting against compensation currents when at least one electric actuator is used jointly by a plurality of independently voltage-supplied control unit devices in redundant systems for autonomous driving. The electric actuator has, in each case, a common connection, via which the electric actuator can be coupled and switched to a common connection of other electrical actuators, and has at least one dedicated connection via which the at least one electric actuator can be individually supplied with current. A number of switching devices corresponding to the common connection and the number of dedicated connections of all the electric actuators is arranged to apply or not apply a switched current in the at least one electric actuator. Provided is at least one current flow blocking device configured to prevent an unwanted current flow to a non-active electronic control unit of the first and second control unit devices.