Vehicle Motion Control via Virtual External Force Feedback
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Solution Overview
Problem
Existing vehicle motion control systems face performance degradation when the estimation accuracy of the vehicle's actual slip angle is reduced, leading to unnatural driving experiences due to decreased motion control precision.
Innovation Solution
A vehicle motion control apparatus that includes sensors for detecting operated and motion states, calculates reference and actual attitude-state quantities, and uses a virtual external force to correct and feedback control signals, allowing the actuator to determine control targets based on slip angle velocity or actual attitude-state quantities depending on accuracy, with a priority system to stabilize vehicle motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vehicle motion control is performed based on estimated vehicle body slip angle, then motion control function is achieved, but motion control performance deteriorates when estimation accuracy is reduced
Solution Approach 1:
The patent introduces a virtual external force as an intermediary element that mediates between the estimated slip angle and the motion control output. By calculating the virtual external force based on the difference between actual and estimated motion state quantities, the system compensates for estimation errors and maintains reliable motion control performance even when slip angle estimation accuracy is reduced
Solution Approach 2:
The patent implements feedback control by continuously calculating the difference between actual and estimated motion state quantities, then using this difference to adjust the virtual external force. This feedback mechanism allows the system to correct for estimation errors in real-time, maintaining motion control performance despite reduced estimation accuracy
2Manufacturing precision
If feedback control is performed to make the difference between reference and actual attitude-state quantities zero, then control precision is improved, but the system becomes sensitive to estimation errors
Solution Approach 1:
The patent applies beforehand cushioning by introducing a virtual external force that anticipates and compensates for estimation errors before they significantly impact control performance. The virtual external force calculation includes terms that cushion against potential estimation inaccuracies, preventing them from causing excessive control reactions or instability
Data Source
AI summary
The vehicle motion control apparatus includes a control unit 37A and sensors 2, 3, 4, 30, 31, 32, 33, etc. The actual state quantity obtaining unit 52 calculates a vehicle body actual slip angle βz_act, etc. The reference dynamic-characteristic model calculating unit 54 calculates a reference vehicle body slip angle βz_d, etc. by using a dynamic characteristic model. The vehicle motion control apparatus also includes a first anti-spin target yaw moment FB unit 68 which calculates a first anti-spin•target yaw moment Mc1_asp based on the vehicle body actual slip angle βz_act and a second anti-spin target yaw moment FB unit 82 which calculates a second anti-spin•target yaw moment Mc2_asp based on a lateral acceleration Gs, a vehicle speed Vact and an actual yaw rate γact.