Vehicle Controller Time-Slot Scheduling for Task Dependency Handling
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Solution Overview
Problem
In distributed execution systems, particularly in motor vehicle controllers, managing interdependencies between task programs across multiple execution units is complex, leading to potential disruptions in real-time capabilities and resource utilization due to the transit time of physical signals and the need for reliable transmission of status variables.
Innovation Solution
A method where task programs are executed in specific time patterns with status variables transmitted in designated time slots, using a hierarchical FID blocking matrix to manage dependencies, ensuring that results and status variables are transmitted efficiently and consistently, allowing for automated generation of the computer program.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If calculation is distributed across multiple execution units to optimize resource utilization, then productivity is improved, but device complexity increases due to managing interdependencies between task programs across execution units
Solution Approach 1:
The system segments task programs into different time patterns and assigns them to specific execution units with dedicated status variables and memory areas. This segmentation isolates the management of interdependencies, allowing each execution unit to operate independently according to its assigned time pattern while maintaining overall system coordination.
Solution Approach 2:
The patent establishes time patterns and assigns task programs to specific execution units before runtime. Status variables are pre-configured with blocking relationships defined in advance through the FID blocking matrix, eliminating the need for complex runtime decision-making and simplifying the management of interdependencies during actual execution.
2Speed
If status variables are transmitted immediately upon ascertainment to ensure real-time capability, then speed is improved, but reliability deteriorates due to potential disruptions in fixed time patterns
Solution Approach 1:
The system transmits status variables periodically at fixed time intervals defined by time patterns, rather than immediately upon ascertainment. Each execution unit operates according to its assigned time pattern, ensuring that transmissions occur at predictable, predetermined moments. This periodic approach maintains real-time capability by guaranteeing fixed transmission timing while ensuring reliable execution of task programs.
3Reliability
If blocking execution of a task program is implemented to ensure reliable transmission of status variables, then reliability is improved, but loss of time increases due to disruption of fixed time pattern execution
Solution Approach 1:
The patent segments the transmission process by assigning dedicated memory areas and status variables to specific execution units and time patterns. Instead of blocking the entire task program execution, only the specific status variable transmission is organized according to the time pattern. This segmentation allows the task program to continue executing while status variables are transmitted at the appropriate predetermined time, eliminating execution delays.
Solution Approach 2:
The system uses dedicated memory areas that serve as copies or buffers for status variables. When a status variable needs to be transmitted, it is copied to the predetermined memory area associated with the receiving execution unit's time pattern. This copying mechanism ensures reliable transmission without blocking the original task program execution, as the transmission operates on a copy rather than the live data stream.
Data Source
AI summary
A method for operating a controller, including: executing a first task-program in a first time pattern of first time-slots, performing a second task-program in a second time pattern of second time-slots, ascertaining a status variable, indicating whether a result of the first task-program is released, ascertaining the result of the first task-program in an instantaneous first time-slot and transmitted in this slot to a memory area assigned to the second task-program, the second task-program ascertains a second result as a function of the status variable value and the result of the first task-program, the status variable value is transmitted in the instantaneous time-slot to a status memory area assigned to the second task-program, the result of the first task-program and the status variables values are ascertained and transmitted after the beginning of execution of the first task-program and before another execution of the first task-program.