Vehicle Weight Estimation via Dynamic Suspension Force Monitoring

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Solution Overview

Problem

Vehicles have limited ability to accurately estimate their weight and the location of their center of gravity, which affects stability and performance, especially when reconfigured or loaded, as existing methods are inaccurate due to static friction and weight transfer during stationary weight estimation.

Innovation Solution

A vehicle suspension system with gas springs and a controller that estimates weight and center of gravity by monitoring pressure and acceleration while the vehicle is moving, using sensors to calculate vertical forces and spring lengths, and disabling estimation if operational conditions are not met to reduce inaccuracies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If weight estimation is performed while the vehicle is stationary, then the measurement process is simple, but the accuracy is reduced due to static friction and weight transfer

Engineering Contradiction:

Improvesimplicity of weight estimation processVSAvoidaccuracy of weight estimation

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transitions the weight estimation process from a static state to a dynamic state by performing measurements while the vehicle is moving. This dynamic approach eliminates the harmful effects of static friction and weight transfer that occur during stationary measurements, thereby improving measurement accuracy while maintaining operational simplicity through automated sensor-based detection.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the vehicle is reconfigured between armored and unarmored configurations or loaded with material and equipment, then the vehicle's weight and center of gravity location change, but existing estimation methods become inaccurate

Engineering Contradiction:

Improveability to handle different configurations and loadsVSAvoidaccuracy of weight and center of gravity estimation

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where sensors continuously monitor the vehicle's operational state, including acceleration, speed, and suspension forces. This real-time feedback allows the system to dynamically adjust weight and center of gravity estimates based on actual vehicle conditions, maintaining accuracy across different configurations and load scenarios.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system accounts for changes in vehicle parameters by using multiple sensors to detect variations in weight distribution and center of gravity location. By monitoring parameters such as suspension spring forces, acceleration, and vehicle speed, the system adapts its calculations to reflect the current configuration state, whether armored, unarmored, or loaded with various materials and equipment.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If weight estimation is performed during vehicle operation, then the information is more useful for real-time control, but inaccuracies occur due to acceleration and terrain variations

Engineering Contradiction:

Improveusefulness of real-time weight informationVSAvoidaccuracy of weight estimation under dynamic conditions

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces multiple intermediary sensors (acceleration sensors, speed sensors, suspension force sensors) that act as mediators between the vehicle's dynamic state and the weight estimation process. These sensors capture intermediate measurements that are then processed to compensate for the effects of acceleration and terrain variations, enabling accurate real-time weight estimation despite dynamic operating conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method provides more accurate weight and center of gravity estimation, improving vehicle stability and performance by reducing static friction and weight transfer, and enabling better leveling and terrain adaptation.

Implementation Method 1

springs coupling the tractive elements to the sprung mass, each spring imparting an upward force on the sprung mass

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 2

load sensors each configured to provide a signal indicative of the force imparted by one of the springs

Methodology Applied

Scientific EffectForce sensing: Force

Data Source

PatentUS11524543B2Systems and methods for determining vehicle characteristics

Publication Date: 2022.12.13 OSHKOSH DEFENSE LLC

AI summary

A vehicle includes a sprung mass including a cabin coupled to a chassis, tractive assemblies each including at least one tractive element, springs coupling the tractive elements to the sprung mass, each spring imparting an upward force on the sprung mass, load sensors each configured to provide a signal indicative of the force imparted by one of the springs, and a controller operatively coupled to the load sensors. The controller is configured to determine a weight of the sprung mass using the signals from the load sensors and monitor at least one operational condition of the vehicle. The controller is configured to determine whether or not to disable determination of the weight based on the at least one operational condition.