Automated Vehicle Stopping Control via Segmented Deceleration
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Solution Overview
Problem
Conventional automated driving methods for motor vehicles face challenges in achieving accurate and safe stopping, particularly in narrow spaces, due to inaccuracies in the braking system and varying initial conditions, leading to premature stopping and reduced stopping accuracy.
Innovation Solution
The method involves accelerating the vehicle to a predefined target velocity, then reducing it to a rolling velocity before reaching a first distance from the target, and further decelerating to a stop at the target location, ensuring a consistent rolling phase that allows for smoother navigation over obstacles and improved accuracy by maintaining a comfortable deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the motor vehicle is decelerated directly from setpoint velocity to target position, then the deceleration duration is extended to maintain comfort, but stopping accuracy deteriorates due to error accumulation from braking system inaccuracies and varying initial conditions
Solution Approach 1:
The deceleration process is divided into two distinct phases: a first deceleration phase from setpoint velocity to rolling velocity, and a second deceleration phase from rolling velocity to standstill. This segmentation allows each phase to be optimized independently - the first phase maintains comfort while the second phase ensures precise stopping, thereby resolving the contradiction between comfort and accuracy.
Solution Approach 2:
The motor vehicle is decelerated to a rolling velocity before reaching the target position, creating a buffer state that allows for subsequent precise positioning. This preliminary deceleration action prepares the system for accurate stopping by reducing velocity to a controllable level before the final positioning maneuver, preventing both premature and late stopping.
2Reliability
If the motor vehicle maintains high velocity close to the target position, then the risk of premature stopping is reduced, but the energy consumption increases and comfort decreases due to extended high-velocity operation
Solution Approach 1:
The system performs preliminary deceleration to a rolling velocity before the vehicle reaches the target position, ensuring that the vehicle is moving at a controlled, low velocity during the critical final approach. This preliminary action prevents premature stopping while avoiding the need to maintain high velocity, thereby optimizing energy consumption.
3Device complexity
If the motor vehicle uses a single deceleration phase to target position, then the control system is simpler, but stopping accuracy deteriorates due to inability to compensate for braking system inaccuracies
Solution Approach 1:
The control system is segmented into two distinct control phases: first, controlling deceleration from setpoint velocity to rolling velocity; second, controlling deceleration from rolling velocity to standstill at the target position. This segmentation increases control precision for stopping accuracy while keeping each individual phase relatively simple, managing overall complexity effectively.
Data Source
AI summary
A method for operating a motor vehicle, the motor vehicle being automatically accelerated and decelerated as a function of an instantaneous position and a predefinable target location, so that it comes to a standstill at the target location, including the following steps: a) accelerating the motor vehicle, in particular from a standstill, to a predefined setpoint velocity; b) up to a predefined first distance of the motor vehicle to the target location, decelerating the motor vehicle to a predefined rolling velocity; c) starting at a predefined second distance of the motor vehicle to the target location, decelerating the motor vehicle to a standstill, the second distance to the target location being smaller than the first distance.