In-Vehicle VM Allocation Control for Buffer Time Shortfalls
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Solution Overview
Problem
Existing in-vehicle control devices with virtual machines face processing delays and failures due to insufficient buffer times, especially when communicating with external devices that experience temporary instability.
Innovation Solution
An in-vehicle control device with a management unit that dynamically adjusts the allocation times of virtual machines based on real-time processing times and buffer times, extending the allocation time of one virtual machine and shortening that of another when buffer times fall below predetermined values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the allocation time of a VM is extended to handle processing delays, then processing reliability is improved, but the productivity of other VMs deteriorates due to reduced allocation time
Solution Approach 1:
The patent implements dynamic allocation time adjustment where the management unit monitors buffer times and processing times in real-time, then extends or shortens allocation times of specific VMs based on current conditions. This dynamic adjustment allows the system to adapt to changing processing requirements while maintaining overall system productivity.
Solution Approach 2:
The patent changes the parameter of allocation time based on monitored buffer time and processing time conditions. When buffer time falls below a threshold or processing time exceeds allocation time, the system modifies the allocation time parameter to prevent processing failures, thereby improving reliability without permanently affecting other VMs' productivity.
2Reliability
If buffer time is increased to prevent processing failures, then reliability is improved, but the allocation time for other VMs is reduced, worsening their productivity
Solution Approach 1:
Instead of statically increasing buffer time for all VMs, the system dynamically adjusts allocation times based on real-time monitoring of buffer time and processing time. This allows buffer time to be increased only when and where needed, preventing processing failures without permanently reducing productivity of other VMs.
Solution Approach 2:
The management unit automatically monitors processing conditions and adjusts allocation times without external intervention. When processing delays are detected, the system self-corrects by extending allocation time to the affected VM, maintaining reliability without manual configuration or permanent buffer time increases that would impact overall productivity.
3Device complexity
If the allocation time is fixed, then system simplicity is maintained, but processing delays occur when external devices become unstable, worsening reliability
Solution Approach 1:
The patent implements a feedback mechanism where the management unit monitors processing time and buffer time of VMs, then uses this feedback to dynamically adjust allocation times. This feedback loop allows the system to respond to external device instability and processing delays without requiring complex predetermined configurations, maintaining relative simplicity while improving reliability.
4Reliability
If processing time monitoring is implemented dynamically, then reliability is improved by preventing processing failures, but the device complexity increases due to additional monitoring and adjustment mechanisms
Solution Approach 1:
The monitoring and adjustment mechanisms form an integrated feedback system within the management unit. By combining monitoring and dynamic adjustment in one centralized component, the patent achieves improved reliability without proportionally increasing device complexity, as the monitoring serves dual purposes of detection and control.
Data Source
AI summary
An in-vehicle control device includes a control unit, a storage unit, and a communication unit, and a management unit that generates a plurality of virtual machines by allocating the physical resources for each allocation time. A first virtual machine executes processing that cannot be carried over to the next cycle. A second virtual machine executes processing that can be carried over to the next cycle. The management unit executes a first change control for changing the allocation time of each of the first virtual machine and the second virtual machine. The first change control includes a control for acquiring a processing time of the first virtual machine in a first cycle, and a control for extending the allocation time of the first virtual machine and shortening the allocation time of the second virtual machine in a cycle, when a buffer time is lower than a first predetermined value.