Steer-by-Wire Signal Correction Using Buffer Delay
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Solution Overview
Problem
The SBW system experiences signal non-linearity issues due to delays or peaks in signals transferred through the vehicle communication network, leading to destabilized steering.
Innovation Solution
A signal correction apparatus and method that includes a command signal receiving/transmitting unit, a buffer unit, and a control unit. The control unit corrects signal linearity by using the original signal and a delayed version of the signal, determined by checking count values of a count signal transmitted in synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If signals are transferred through the vehicle communication network (CAN communication), then the steering angle command can be transmitted from the steering wheel to the steering actuator, but the signal linearity is degraded due to delays or peaks occurring in the transmitted signal
Solution Approach 1:
The patent applies preliminary action by storing the original command signal in advance in a buffer unit before transmission through the communication network. This stored signal is then used for correction purposes to compensate for linearity degradation that occurs during transmission, effectively preparing a reference signal beforehand to fix the distortion issue.
Solution Approach 2:
The patent implements feedback by comparing the transmitted command signal with the originally stored signal and using the detected linearity degradation (delays or peaks) to correct the transmitted signal. The control unit continuously monitors signal linearity and adjusts the command signal based on this feedback to maintain accurate steering control despite communication network disturbances.
2Reliability
If a filter is used to correct signal linearity, then signal stability can be improved, but the system complexity increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a buffer unit that stores the original command signal as a reference. This stored signal acts as an intermediary reference against which the transmitted signal can be compared and corrected, avoiding the need for complex filter circuits while maintaining signal stability and linearity.
Solution Approach 2:
The patent applies copying by creating a duplicate copy of the original command signal and storing it in the buffer unit. This copied signal serves as a reference template for correcting the transmitted signal's linearity degradation, providing a simple yet effective method to restore signal accuracy without complex filtering hardware.
Data Source
AI summary
A signal correction apparatus of an SBW system may include: a command signal receiving/transmitting unit configured to receive a command signal transmitted through a vehicle communication network by an upper level apparatus, and transmit a command signal, obtained by correcting the linearity of the received command signal, to a lower level apparatus through the vehicle communication network; a buffer unit configured to store the command signal, received through the command signal transmitting/receiving unit, as an original signal; and a control unit configured to generate a command signal whose linearity is corrected, by correcting the linearity of the original signal by using the original signal stored as the command signal in the buffer unit and a command signal obtained by delaying the command signal, stored in the buffer unit, by designated one unit time.