Powertrain Torque Control at Deceleration End Under Network Delay
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Solution Overview
Problem
The instability in control stability at the end of deceleration control due to communication delays in in-vehicle networks affects the braking and driving forces, leading to potential control hunting and delayed convergence of the degeneration process in driving assist systems.
Innovation Solution
A control device that acquires ending information from a driving assist system and stabilizes the driving and braking forces by setting a lower limit torque, ensuring the powertrain does not generate forces beyond this limit, thereby enhancing control stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback control based on acquired lower limit torque value is performed, then degeneration control can be executed, but communication delay causes the lower limit value to not be followed and control stability deteriorates
Solution Approach 1:
The control device performs preliminary actions by detecting the degeneration control state and proactively suppressing output torque above the lower limit torque before communication delays can cause instability. This advance intervention ensures that the powertrain output remains stable during the degeneration process without waiting for delayed feedback information.
Solution Approach 2:
The control device acts as an intermediary between the driving assist system and the powertrain control, mediating the torque output by suppressing excessive torque generation. This intermediary control function ensures that even when communication delays occur, the powertrain output remains within acceptable limits and follows the intended degeneration trajectory.
2Measurement precision
If degeneration control is delayed due to communication delay, then the lower limit value cannot be followed, but maintaining strict adherence to lower limit torque may cause unnecessary torque suppression
Solution Approach 1:
The control device dynamically adjusts torque suppression based on the detected degeneration control state. By monitoring whether the driving assist system is in degeneration mode, the control device applies torque suppression only when necessary (during degeneration), rather than continuously. This dynamic approach maintains precise torque control during critical phases while avoiding unnecessary energy loss during normal operation.
Data Source
AI summary
A control device includes: an acquisition unit configured to acquire, from a driving assist system, a requested acceleration and ending information indicating an end of a deceleration control; and a control unit configured to control a powertrain and a brake based on the requested acceleration, and perform a prescribed process of stabilizing a driving force and a braking force that are generated in an ending process of the deceleration control based on the requested acceleration when the acquisition unit acquires the ending information.