Vehicle Trajectory Control with Fail-Safe Emergency Stop Paths

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Solution Overview

Problem

Existing vehicle control systems face safety risks when the target trajectory generation unit malfunctions, leading to the loss of appropriate control over vehicle travel.

Innovation Solution

The system generates and stores both a first target trajectory for normal driving and a second target trajectory for deceleration and stopping, allowing the vehicle to safely stop when the generation unit malfunctions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the system uses a single target trajectory generation unit for normal driving control, then the control system is simple and efficient, but the system reliability deteriorates when the unit malfunctions

Engineering Contradiction:
Improvevehicle traveling safetyVSAvoidcontrol system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system generates and stores a second target trajectory in advance that is specifically designed for emergency stopping scenarios. This preliminary preparation ensures that when a malfunction occurs, the control system can immediately switch to using the pre-computed emergency trajectory without needing to calculate a new one during the crisis, thus maintaining reliability while avoiding the complexity of real-time emergency computation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the parameters of the target trajectory based on the operational state. During normal operation, the first target trajectory parameters are used for smooth driving. When a malfunction is detected, the system switches to the second target trajectory parameters that are specifically configured for emergency stopping, allowing the same control system to handle both normal and emergency conditions effectively

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the system generates and stores multiple target trajectories (first for normal driving, second for emergency stopping), then the system reliability improves, but the device complexity increases

Engineering Contradiction:
Improvevehicle traveling safetyVSAvoidtrajectory management structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The target trajectory generation function is segmented into two distinct modes: normal driving mode with its dedicated first target trajectory, and emergency stopping mode with its dedicated second target trajectory. This segmentation allows each trajectory type to be optimized for its specific purpose while maintaining clear separation in the control logic, improving reliability without creating excessive complexity through functional modularity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The target trajectory generation unit is designed to perform multiple functions by generating different types of trajectories based on the operational state. The same unit that generates normal driving trajectories also generates emergency stopping trajectories, eliminating the need for separate dedicated systems and achieving multi-functionality that improves reliability without proportionally increasing device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the vehicle executes control based on the second target trajectory for emergency stopping, then the vehicle safety is secured during malfunction, but the normal driving efficiency is reduced due to the need to maintain emergency trajectory readiness

Engineering Contradiction:
Improvevehicle safety during malfunctionVSAvoiddriving efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The second target trajectory for emergency stopping is generated and stored in advance during normal operation, rather than being computed in real-time when needed. This preliminary action ensures that the emergency trajectory is ready immediately when a malfunction occurs, securing vehicle safety without imposing any computational burden during normal driving that would reduce efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous readiness for emergency stopping by having the second target trajectory generation capability active throughout normal operation. However, since the trajectory is pre-computed and stored, no additional computational resources are consumed during normal driving, allowing continuous useful action (normal driving) to proceed at full efficiency while emergency readiness is maintained in the background

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3819181B1Vehicle control system
Publication Date: 2025.08.20 TOYOTA JIDOSHA KK
  • EP3819181B1 patent drawingFigure 1
  • EP3819181B1 patent drawingFigure 2
  • EP3819181B1 patent drawingFigure 3~4

AI summary

A target trajectory generation device (100, 100-A, 100-B) generates and outputs target trajectories each including a target position and a target speed of a vehicle. A first target trajectory is intended to perform at least one of steering, acceleration, and deceleration of the vehicle. A second target trajectory is intended to decelerate and stop the vehicle. When a malfunctioning device (100F) does not exist, a vehicle traveling control device executes vehicle traveling control based on the first target trajectory. When the malfunctioning device (100F) exists, the vehicle traveling control device stops the vehicle by executing the vehicle traveling control based on the second target trajectory output before the malfunction occurs, or based on the second target trajectory output from the target trajectory generation device (100, 100-A, 100-B) other than the malfunctioning device (100F).