Feed-forward Torque Compensation for Brake-to-Steer Longitudinal Disturbance
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Solution Overview
Problem
Brake-to-steer functionality in vehicles often causes undesirable slowing, which is not aligned with driver intent, as it affects the vehicle's longitudinal acceleration and speed.
Innovation Solution
Implementing a feed-forward gain on vehicle propulsion torque to manage longitudinal acceleration and speed disturbances during brake-to-steer scenarios, by using powertrain torque requests to compensate for braking and replicate the behavior of a normally functioning vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If brake-to-steer functionality is used to steer the vehicle, then steering capability is improved, but longitudinal acceleration and vehicle speed deteriorate due to undesirable slowing
Solution Approach 1:
The controller applies preliminary anti-action by detecting brake-to-steer activation and calculating compensatory propulsion torque requests before the speed loss occurs. The propulsion system pre-compensates for the expected deceleration by applying additional torque, thereby counteracting the harmful speed reduction effect before it fully manifests, maintaining vehicle speed while preserving brake-to-steer functionality
Solution Approach 2:
The controller dynamically changes the propulsion torque parameter in response to brake-to-steer activation. By adjusting the propulsion torque request based on the relationship between brake torque and vehicle speed, the system modifies the propulsion parameter to compensate for the speed loss caused by braking, thereby maintaining desired vehicle speed while allowing brake-to-steer operation
2Ease of operation
If brake-to-steer functionality is used to steer the vehicle, then steering capability is improved, but longitudinal acceleration deteriorates due to deceleration
Solution Approach 1:
The controller applies preliminary anti-action by detecting brake-to-steer activation and calculating compensatory propulsion torque requests before the acceleration loss occurs. The propulsion system pre-compensates for the expected deceleration by applying additional torque, thereby counteracting the harmful acceleration reduction effect before it fully manifests, maintaining longitudinal acceleration while preserving brake-to-steer functionality
Solution Approach 2:
The controller dynamically changes the propulsion torque parameter in response to brake-to-steer activation. By adjusting the propulsion torque request based on the relationship between brake torque and vehicle speed, the system modifies the propulsion parameter to compensate for the acceleration loss caused by braking, thereby maintaining desired longitudinal acceleration while allowing brake-to-steer operation
Data Source
AI summary
A number of illustrative variations may include a system and method of controlling vehicle slowing while implementing brake-to-steer functionality that may include providing a feed-forward gain on vehicle propulsion torque to achieve or maintain target longitudinal acceleration and replicate the behavior of a vehicle not using brake-to-steer. The system may manipulate propulsion of the vehicle to manage longitudinal acceleration disturbance and speed disturbance during brake-to-steer.