Vehicle Steering Control Circuit Self-Inspection Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle control systems face challenges in performing self-inspection at appropriate timing, particularly when the ignition switch is turned off, as the rotation monitoring circuit is unable to obtain the number of rotations of the motor, and the self-inspection function interferes with the operational state of the control circuit.
Innovation Solution
A vehicle control apparatus comprising a first circuit continuously supplied with power for detecting state variables, a second circuit initiated upon vehicle power supply start for specific processes, and a third circuit performing inspections of the first circuit before the second circuit starts, allowing self-inspection without interfering with operational states and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotation monitoring circuit continuously monitors motor rotations even when the ignition switch is turned off, then the steered angle can be correctly obtained after power restoration, but the circuit cannot perform self-inspection when the second circuit is operating
Solution Approach 1:
The inspection circuit performs self-inspection of the rotation monitoring circuit before the second circuit (control circuit) is activated. This preliminary action ensures the monitoring circuit is functional before it begins its critical monitoring task, allowing the system to detect faults early while avoiding conflicts with the control circuit's operation.
Solution Approach 2:
The system dynamically adjusts the operational state of different circuits based on the ignition switch state. The first circuit (rotation monitoring circuit) remains active continuously, while the second circuit (control circuit) is activated only when needed. The inspection circuit operates in the time window before the second circuit starts, adapting to the dynamic power management requirements.
2Reliability
If the self-inspection function is performed in the rotation monitoring circuit, then functional safety requirements are met, but the monitoring function is stopped during inspection
Solution Approach 1:
The self-inspection is performed in advance, before the rotation monitoring circuit begins its monitoring function. By conducting the inspection preliminarily, the system ensures safety compliance while minimizing any interruption to the monitoring function, as the circuit is already operational and can resume monitoring immediately after inspection.
Solution Approach 2:
The inspection circuit operates periodically or at specific intervals rather than continuously interfering with the monitoring function. This periodic action allows the monitoring circuit to maintain its function while the inspection circuit performs its safety checks at appropriate moments, reducing the loss of monitoring time.
3Reliability
If power is supplied to the control circuit when the ignition switch is turned off, then the circuit can monitor steered angle and motor rotations, but power consumption increases
Solution Approach 1:
The power supply system is segmented into multiple circuits with different power requirements. The first circuit (rotation monitoring circuit) is supplied with power continuously at a lower power level to maintain basic monitoring functions. The second circuit (control circuit) is supplied with power only when the ignition switch is on, consuming more power but only when full functionality is needed. This segmentation optimizes overall power consumption while maintaining monitoring availability.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A vehicle control apparatus capable of performing a self-inspection at an appropriate timing is provided. An ECU of a vehicle controls a motor which is a source of a torque applied to a steering mechanism of the vehicle. The ECU includes a microcomputer (42) and a monitoring circuit (43). The monitoring circuit (43) includes a rotation detection circuit that detects the number of rotations of the motor at a preset sampling interval, a control circuit including a logic circuit that controls an operation of the rotation detection circuit, and an inspection circuit (77) that performs an inspection of the control circuit. The microcomputer (42) is started upon start of vehicle power supply and performs a specific process using the number of rotations of the motor detected by the rotation detection circuit. The inspection circuit (77) performs the inspection of the control circuit in the monitoring circuit (43) in a period (time t2 to time t3) in which the microcomputer (42) is kept in a reset state after the vehicle power supply is turned on and which is within a sampling interval (ΔTb) of the rotation detection circuit in the monitoring circuit (43).