3D Map and IMU Grade Angle Estimation for Proactive Cruise Control
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Solution Overview
Problem
Existing adaptive cruise control systems rely on reactive estimates of roadway grade based on inertial measurement unit (IMU) measurements, which fail to proactively react to changes in grade, leading to inadequate control during transitions.
Innovation Solution
A grade angle estimation system that combines three-dimensional map data with IMU measurements, employing an arbitration strategy to determine a look-ahead grade angle and using a lagless filter to compensate for time lag, enabling preemptive control actions by vehicular systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If reactive grade estimation using IMU measurements is used, then the system structure is simple, but the system cannot proactively react to grade transitions
Solution Approach 1:
The system performs preliminary action by using three-dimensional map data to predict upcoming grade changes before the vehicle actually encounters them. The look-ahead grade angle from map data allows the adaptive cruise control system to prepare for grade transitions in advance, rather than reacting only after the IMU detects the change has already occurred.
Solution Approach 2:
The patent introduces an intermediary approach by combining map data with IMU measurements through a filter. The map data serves as a predictive intermediary that bridges the gap between current IMU measurements and future grade conditions, allowing the system to anticipate changes while maintaining structural simplicity.
2Adaptability or versatility
If map data is integrated with IMU measurements, then proactive control is enabled, but device complexity increases
Solution Approach 1:
The system achieves multi-functionality by using a single integrated controller that processes both map data and IMU measurements. The same controller that manages adaptive cruise control also performs grade angle estimation and filtering, eliminating the need for separate dedicated hardware modules and reducing overall system complexity despite the enhanced functionality.
Solution Approach 2:
The patent merges map data processing with IMU-based grade estimation into a unified system. The filter combines information from both sources to produce a single grade angle output, consolidating multiple functions into one integrated process rather than maintaining separate parallel systems.
3Reliability
If filtered grade data with time constant is used, then noise is reduced, but time lag is introduced
Solution Approach 1:
The system compensates for the time lag introduced by filtering by using look-ahead map data. The predictive nature of map-based grade angles provides advance information that counteracts the delay caused by the filter's time constant, ensuring that the control system receives timely grade information despite the smoothing effect of filtering.
Data Source
AI summary
A grade angle estimation system for estimating a grade angle of a roadway that a vehicle is driving along includes one or more controllers. The one or more controllers include one or more processors that execute instructions to receive three-dimensional map data of the roadway and measurements indicating a grade angle of the roadway collected by an inertial measurement unit (IMU). The one or more controllers determine an IMU-based grade angle based on the measurements received by the IMU and compare an absolute value of the IMU-based grade angle with a threshold grade value. In response to determining the absolute value of the IMU-based grade angle is greater than the threshold grade value, the one or more controllers set the grade angle equal to the IMU-based grade angle.