Autonomous Vehicle Trajectory Planning with Segmented Control Durations

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Solution Overview

Problem

Autonomous vehicles experience sudden movements due to computational latencies introduced when updating trajectory plans during control computations, leading to an uneven ride experience for passengers.

Innovation Solution

A trajectory planning system that fixes steering parameters and speed parameters for different durations, allowing the vehicle to compute controls without parameter changes during computation, thereby reducing latency and ensuring smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the trajectory plan is updated during control computations, then the vehicle can adapt to changing operating conditions, but computational latencies are introduced causing sudden movements

Engineering Contradiction:

Improveadaptability to changing operating conditionsVSAvoidcontrol smoothness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The trajectory plan is divided into a fixed portion and a variable portion. The fixed portion contains parameters that remain constant during control computation, while the variable portion can be updated. This segmentation allows the system to adapt to changing conditions through the variable portion without introducing latencies that would affect the fixed portion, thereby maintaining control smoothness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fixed portion of the trajectory plan is determined in advance before control computations begin. By pre-establishing these fixed parameters, the system eliminates the need to recalculate them during control execution, preventing computational latencies from causing sudden movements while still allowing the variable portion to adapt to new conditions.

Inventive Principle:

Principle #10Preliminary action

2Speed

If the trajectory plan is updated frequently, then the vehicle responds quickly to changes, but computational latencies increase causing unexpected maneuvers

Engineering Contradiction:

Improveresponse speed to changesVSAvoidcontrol stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

By segmenting the trajectory plan into fixed and variable portions, the system can update the variable portion frequently to maintain fast response to changes, while the fixed portion remains stable during computation. This prevents the computational latencies that would otherwise cause unexpected maneuvers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts which portion of the trajectory plan is fixed and which is variable based on computational timing. When computation latency is detected or anticipated, the system can extend the fixed portion duration, creating a dynamic balance between response speed and control stability.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If steering and speed parameters are fixed for the same duration, then the control computation is simplified, but the vehicle cannot optimize for different parameter requirements

Engineering Contradiction:

Improvecontrol computation complexityVSAvoidparameter optimization capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The trajectory plan is segmented into different parameter types (steering and speed) with different fixed durations. Steering parameters can be fixed for a longer duration while speed parameters are fixed for a shorter duration, allowing each parameter type to be optimized independently without increasing overall computational complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the trajectory plan have different qualities in terms of fixed duration. Steering parameters receive longer fixed durations for stability, while speed parameters have shorter fixed durations for responsiveness. This local differentiation optimizes each parameter's performance characteristics.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10037037B1Systems and methods for trajectory planning in an autonomous vehicle using different fixed durations for steering and speed parameters

Publication Date: 2018.07.31 TOYOTA JIDOSHA KK

AI summary

System, methods, and other embodiments described herein relate to autonomously controlling a vehicle according to a trajectory plan. In one embodiment, a method includes updating, upon traveling over at least a portion of a current segment of a roadway, the trajectory plan for a subsequent segment of the roadway by setting a fixed portion of the trajectory plan to include: (i) a steering parameter to be fixed for a first duration of time and (ii) a speed parameter to be fixed for a second duration of time. The first duration of time and the second duration of time are of different lengths. The method includes computing input controls for autonomously controlling the vehicle according to the fixed portion of the trajectory plan. The method includes controlling the vehicle according to the input controls over the subsequent segment of the roadway.