Vehicle Trajectory Suitability Checks Under Friction and Power Limits
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Solution Overview
Problem
Existing technologies lack an efficient method to determine the drivability of target trajectories for autonomous vehicles, particularly in assessing the suitability of trajectories based on road surface conditions and vehicle capabilities.
Innovation Solution
A method that detects and estimates slope, transverse incline, and friction value of the road surface along a target trajectory using sensors and map data. It calculates target traction, tractive power, steering power, and tire forces using model equations, and assesses the trajectory's suitability by comparing these values against predetermined curves and limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trajectory planning for autonomous vehicles is performed without a systematic drivability assessment method, then the vehicle can operate autonomously, but the trajectory may be unsuitable for the actual road conditions and vehicle capabilities, leading to control failures
Solution Approach 1:
The patent applies preliminary action by assessing trajectory suitability before the vehicle executes the trajectory. The system detects road parameters (slope, transverse incline, friction) and calculates required traction, tractive power, and steering power in advance, comparing these against predetermined curves and limits to determine if the trajectory is drivable before commitment to execution.
Solution Approach 2:
The patent uses an intermediary assessment mechanism that acts as a mediator between trajectory planning and vehicle execution. The suitability assessment system serves as an intermediary layer that translates road conditions and vehicle capabilities into drivability criteria, enabling the control system to select appropriate trajectories without directly managing the complexity of physical vehicle-dynamics calculations.
2Reliability
If the vehicle operates on trajectories without assessing road friction and slope conditions, then the control system remains simple, but the vehicle may attempt impossible maneuvers on unsuitable road surfaces
Solution Approach 1:
The patent applies universality by using a multi-functional assessment system that evaluates multiple trajectory parameters (traction, tractive power, steering power) against multiple road conditions (slope, transverse incline, friction) using a unified set of predetermined curves and limits. This universal approach enables comprehensive drivability assessment without requiring separate specialized systems for each parameter.
Solution Approach 2:
The patent applies parameter changes by transforming road surface parameters (slope, transverse incline, friction) and trajectory parameters (traction, power) into comparable forms against predetermined characteristic curves. The system changes the representation of these parameters to enable systematic comparison and suitability determination.
3Measurement precision
If the system calculates detailed target traction and steering power for every trajectory, then accurate drivability assessment is achieved, but the computational load increases significantly
Solution Approach 1:
The patent applies partial action by calculating only the essential trajectory parameters (target traction, target tractive power, target steering power) needed for drivability assessment rather than performing complete vehicle dynamics simulations. This partial calculation approach provides sufficient accuracy for suitability determination while reducing computational requirements.
Data Source
AI summary
A method for checking the suitability of a target trajectory for trajectory control of a vehicle. The target trajectory contains route information about the path of a route to be driven and momentum information about the momentum with which the route should be driven. The target trajectory is assessed as suitable for the trajectory control if the target traction and target tractive power are below a predetermined characteristic traction curve or characteristic tractive power curve, the target steering power is below a predetermined power limit of the steering, and the horizontal target tire forces on each wheel are within the friction value limits determined by the friction value. Otherwise, the target trajectory is assessed to be unsuitable.