Power Steering Torque Signal Pre-Judgment Circuit
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Solution Overview
Problem
The existing electric power steering device configuration increases the operation load of the CPU due to the need for it to process multiple signals, which becomes more pronounced with the addition of more sensors in multifunctional devices, requiring high-performance CPUs.
Innovation Solution
A second microprocessor is introduced between the steering state detection unit and the control device, which compares signals from the steering state detection unit and judges their normalcy, thereby reducing the CPU's operation load by performing normal and abnormality judgments beforehand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the CPU processes multiple signals directly without preliminary judgment, then the device can maintain a simpler structure, but the operation load of the CPU increases significantly
Solution Approach 1:
The patent divides the signal processing function into two segments: a first judgment circuit that performs preliminary normal/abnormal judgment of multiple signals, and a second judgment circuit in the control device that processes only the judged results. This segmentation reduces the CPU operation load while maintaining structural simplicity.
Solution Approach 2:
The first judgment circuit acts as an intermediary between the steering state detection unit and the control device. It preprocesses the signals by comparing them and determining normalcy before transmission, thereby reducing the processing burden on the CPU in the control device.
2Adaptability or versatility
If more sensors are mounted to achieve multifunctionality, then the device functionality is improved, but the operation load of the CPU increases
Solution Approach 1:
The first judgment circuit performs preliminary judgment of signal normalcy before the signals reach the control device. This preliminary action allows the system to handle multiple sensors and signals without overloading the CPU, as the heavy comparison work is done in advance.
3Device complexity
If the CPU performs all signal comparisons and abnormality judgments, then the control logic can be simpler, but the processing time and operation load increase
Solution Approach 1:
The first judgment circuit performs signal comparison and abnormality judgment in advance before the control device receives the signals. This preliminary action reduces the processing time at the CPU level, as the time-consuming comparison operations are completed beforehand.
Data Source
AI summary
A CPU 38 is connected to a first judgment circuit 36 accommodated in a sensor housing 15 through a first signal line 44A and a second signal line 45A. The first judgment circuit 36 is connected to first to fourth torque detection elements 32a, 33a, 34a and 35a of a quadruple torque sensor 16 through first to fourth torque signal lines 46, 47, 48 and 49. Normal and abnormality of torque signals from the torque detection elements 32a, 33a, 34a and 35a are judged are judged by a predetermined judgment manner in the first judgment circuit 36. Then, two normal torque signals, which have been judged to be normal, are transmitted to the CPU 38 through the first signal line 44A and the second signal line 45A.