Vehicle Control Device Velocity-Dependent Acceleration Patterns
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Solution Overview
Problem
Existing vehicle control systems struggle to accurately control vehicles to stop within permitted intervals of distance in the worst-case scenario, considering factors like stoppage delays, acceleration, braking, and track gradients, as per IEEE1474 standards.
Innovation Solution
A vehicle control device and method that calculates powering, coasting, and braking patterns using acceleration characteristics dependent on vehicle velocity, allowing for precise control by determining switching positions and velocities within these patterns to ensure safe stopping within predetermined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the vehicle control system uses fixed acceleration values for calculating braking patterns, then the calculation process is simple, but the accuracy of allowable velocity calculation deteriorates because acceleration characteristics actually depend on vehicle velocity
Solution Approach 1:
The patent applies dynamics by making the acceleration values dynamic rather than fixed. The acceleration characteristic values are selected based on the current vehicle velocity, so the calculation parameters adapt to the actual operating conditions. This resolves the contradiction by introducing velocity-dependent acceleration values that improve accuracy while maintaining a relatively simple calculation structure through predefined acceleration characteristics.
Solution Approach 2:
The patent changes the parameter of acceleration from a fixed value to a velocity-dependent value. By selecting acceleration characteristic values that correspond to different velocity ranges, the system achieves more accurate allowable velocity calculations. This parameter change approach improves measurement precision without significantly complicating the overall calculation process.
2Reliability
If the vehicle control system calculates detailed powering and coasting patterns with velocity-dependent acceleration, then the reliability of stop control in worst-case scenarios improves, but the computational load and processing time increase
Solution Approach 1:
The patent segments the braking delay period into distinct phases: powering interval, coasting interval, and braking interval. Each phase has its own velocity pattern (powering pattern, coasting pattern, braking pattern) with appropriate acceleration characteristics. This segmentation allows the system to calculate reliable stop control for worst-case scenarios by considering all possible velocity patterns, while managing computational load through structured phase-based calculation.
Solution Approach 2:
The patent performs preliminary calculation of multiple velocity patterns (powering pattern, coasting pattern, braking pattern) before actual braking is needed. By pre-calculating allowable velocities for different scenarios and selecting the most restrictive (worst-case) pattern, the system ensures reliable stop control while reducing real-time processing requirements during emergency situations.
3Measurement precision
If the vehicle control system considers multiple velocity patterns (powering, coasting, braking) with velocity-dependent acceleration characteristics, then the accuracy of determining switching positions and velocities improves, but the device complexity and computational requirements increase
Solution Approach 1:
The patent uses dynamic acceleration characteristics that vary with velocity to accurately determine switching positions and velocities between different intervals. By selecting acceleration values that match the current velocity range, the system achieves precise switching point calculation while maintaining a manageable control structure through velocity-based parameter selection.
Solution Approach 2:
The patent changes acceleration parameters based on velocity conditions to accurately determine switching positions. Different acceleration characteristic values are applied in different velocity ranges and intervals, enabling precise calculation of switching points and velocities. This parameter adaptation improves measurement precision without requiring overly complex control logic.
Data Source
AI summary
A powering pattern representing velocity of a vehicle at each position of a powering interval in a braking delay period between a timing at which the vehicle exceeds allowable velocity and a braking timing at which the vehicle starts to brake, and a coasting pattern representing velocity of the vehicle at each position of a coasting interval subsequent to the powering interval in the braking delay period are calculated after calculating a braking pattern representing velocity of the vehicle in a braking interval, which is a running interval subsequent to the coasting interval and which occurs between a position of the vehicle at the braking timing and a target position for controlling the vehicle to run at predetermined velocity or less, wherein an acceleration characteristic depending on velocity of the vehicle is used to calculate at least the powering pattern.