Vehicle Curve Speed Control Using Lateral Acceleration Feedback
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Solution Overview
Problem
Existing automated speed control systems for vehicles, such as ACC, rely heavily on navigation system data for curve handling, which can be uncertain, leading to potential dangers due to estimation errors.
Innovation Solution
A method that measures real-time lateral acceleration and adjusts the longitudinal speed setpoint based on this measurement, independent of navigation system data, using existing vehicle sensors, to maintain acceptable lateral acceleration and avoid unnecessary braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If navigation system data is used to construct trajectory and speed profile for curve handling, then curve anticipation is enabled, but estimation errors occur due to information uncertainties
Solution Approach 1:
The patent implements a feedback mechanism by measuring actual lateral acceleration experienced by the vehicle and using this measurement to adjust the longitudinal speed setpoint in real-time. This closed-loop feedback replaces reliance on uncertain navigation system predictions with direct sensory feedback from the vehicle's actual motion state, thereby resolving the contradiction between curve handling capability and speed control accuracy.
Solution Approach 2:
The patent substitutes the navigation system's computational trajectory planning with a physics-based approach using lateral acceleration measurements. Instead of relying on GPS and map data to calculate required speed adjustments, the system directly measures the lateral forces acting on the vehicle and derives speed control commands from these physical measurements, improving reliability by replacing uncertain informational systems with direct physical sensing.
2Reliability
If real-time lateral acceleration measurement is used to adjust speed setpoint, then navigation system uncertainty impact is reduced, but control system complexity increases
Solution Approach 1:
The patent leverages the existing multi-functional sensor suite already present in modern vehicles (inertial sensors for lateral acceleration, steering angle sensors, and navigation systems). By making these existing sensors serve the additional function of real-time curve speed control, the system achieves improved reliability without adding dedicated new hardware, thereby minimizing the increase in overall system complexity.
Solution Approach 2:
The control system uses the vehicle's own existing sensors and computational resources to perform the curve speed control function. The inertial measurement unit, steering angle sensor, and processor that already serve other vehicle functions are repurposed to provide lateral acceleration-based speed adjustment, allowing the system to be self-sufficient and avoiding the need for additional specialized components.
3Object-affected harmful factors
If vehicle speed is adjusted based on lateral acceleration to maintain comfort, then passenger comfort is improved, but vehicle productivity decreases due to speed reduction
Solution Approach 1:
The patent implements dynamic speed adjustment that adapts in real-time to the actual lateral acceleration conditions. Rather than applying fixed speed limits in curves, the system continuously modifies the speed setpoint based on measured lateral acceleration, allowing the vehicle to maintain higher speeds when conditions permit and reduce speed only when necessary to maintain comfort, thereby optimizing the trade-off between comfort and productivity.
Solution Approach 2:
The system dynamically changes the longitudinal speed setpoint parameter based on real-time lateral acceleration measurements. By continuously adjusting this critical parameter according to actual vehicle dynamics rather than relying on pre-defined navigation profiles, the system maintains passenger comfort through appropriate speed reduction while minimizing the impact on overall vehicle productivity and travel time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the impact of navigation system uncertainties by dynamically controlling vehicle speed to ensure safe and comfortable handling of curves without additional costs or sensors, applicable to both equipped and non-equipped vehicles.
Implementation Method 1
a) measuring, with an inertial sensor (17), a lateral acceleration of the vehicle (10)
Data Source
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Figure 3
Figure 4~6
AI summary
The invention relates to a method for controlling a motor vehicle (10), comprising: - a verification step during which a computer (11) installed in the motor vehicle checks whether the vehicle is at the entrance to a curve (21; 22) or in a curve, and, if so, - a determination step during which the computer determines a longitudinal speed setpoint, and - a control step during which the vehicle is controlled according to the longitudinal speed setpoint. According to the invention, the method includes, before the determination step, a step for acquiring a lateral acceleration experienced by the motor vehicle, and the longitudinal speed setpoint is determined as a function of the lateral acceleration thus acquired.