Adaptive MPC Vehicle Route Planning

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Solution Overview

Problem

Existing model predictive control (MPC) systems for vehicle route planning face challenges in reducing computation time, particularly with long time horizons, which can lead to unacceptably long computation times and loss of model resolution and disturbance resolution.

Innovation Solution

The method involves estimating vehicle parameters online and compressing the number of parameters for future engine torque to minimize fuel consumption, allowing for faster convergence to the optimal result without sacrificing model resolution, and incorporating online torque converter modeling to handle discrete events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a long time horizon is used in MPC for optimal route planning, then the computed inputs approach the optimal solution, but the computation time becomes unacceptably long

Engineering Contradiction:
Improveoptimality of velocity profileVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the long time horizon into multiple shorter time horizons or segments. Instead of solving one large optimization problem over the entire route, the system solves a sequence of smaller MPC problems over shorter prediction horizons. This segmentation reduces the computational complexity of each individual optimization problem while collectively achieving coverage of the full time horizon, thus balancing optimality with computational feasibility.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the sampling frequency is increased to preserve model resolution and disturbance resolution, then the time horizon length increases, but the number of inputs to optimize increases leading to longer computation time

Engineering Contradiction:
Improvemodel resolution and disturbance resolutionVSAvoidoptimization speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts and removes redundant or less significant inputs from the optimization problem. By identifying and eliminating unnecessary control variables or states that do not significantly impact the optimal solution, the system reduces the dimensionality of the optimization problem. This allows for higher sampling frequencies and better resolution without proportionally increasing computational burden, as the number of active optimization variables is reduced.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If a short time horizon with low sampling frequency is used to reduce computation time, then the number of inputs to optimize decreases, but the model resolution and disturbance resolution are lost

Engineering Contradiction:
Improvecomputation speedVSAvoidmodel resolution and disturbance resolution
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements dynamic adjustment of the time horizon length and sampling frequency based on operating conditions, vehicle state, and route characteristics. Rather than using fixed parameters, the system adapts the prediction horizon and sampling rate in real-time. This allows the system to use shorter horizons and lower sampling frequencies when computational resources are constrained or conditions are stable, while switching to longer horizons and higher frequencies when precision is critical, thus dynamically balancing computation speed with resolution quality.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS10060370B2Adaptive model predictive control for vehicle route planning
Publication Date: 2018.08.28 FORD GLOBAL TECH LLC
  • US10060370B2 patent drawing
  • US10060370B2 patent drawing
  • US10060370B2 patent drawing

AI summary

Method and system are provided for vehicle route planning based on adaptive model predictive control. In one example, a method may include real-time online identification of the vehicle model base on the vehicle inputs and outputs; compression of the input space to increase the optimization efficiency; and optimization of the route planning based on the model parameter of the vehicle and the known road grade.