Hitch Angle Correction Using Kinematic Model and Ultrasonic Sensors

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Solution Overview

Problem

Existing vehicle control systems that determine hitch angle for trailers using vision-based methods are costly, require significant processing power, and have performance limitations due to light conditions, making them unreliable for accurate hitch angle measurement.

Innovation Solution

A system that uses a combination of a kinematic model and inputs from ultrasonic sensors to estimate and correct the hitch angle, employing a Kalman filter to minimize errors and provide reliable hitch angle data for driver assistance and vehicle control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If vision-based methods are used to determine hitch angle, then measurement capability is provided, but cost and processing power requirements increase significantly

Engineering Contradiction:

Improvehitch angle measurementVSAvoidsystem cost and processing power

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces vision-based optical measurement systems with a mechanical/kinematic model-based approach. Instead of using cameras and image processing to determine hitch angle, the system uses a kinematic model that calculates hitch angle from measurements of other parameters (steering angle, vehicle speed, trailer speed) through mathematical relationships, thereby eliminating the need for expensive vision-based ranging hardware and significant processing power.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a kinematic model as an intermediary computational layer between physical sensor measurements and the final hitch angle determination. The model acts as a mediator that transforms easily measurable parameters (steering angle, velocities) into the desired hitch angle information through mathematical relationships, avoiding direct measurement complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If vision-based methods are used to determine hitch angle, then measurement capability is provided, but performance is limited by light conditions

Engineering Contradiction:

Improvehitch angle measurementVSAvoidperformance under various light conditions

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces light-dependent vision-based measurement systems with a kinematic model that relies on mechanical parameters (steering angle, vehicle speed, trailer speed) and mathematical relationships. This substitution eliminates dependence on light conditions entirely, as the calculation is based on inertial and kinematic properties that are independent of illumination, thereby improving reliability across all environmental conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameters from optical quantities (which are light-dependent) to mechanical/kinematic parameters (steering angle, velocities) that are inherently independent of light conditions. By measuring and calculating based on these alternative parameters through the kinematic model, the system achieves reliable hitch angle determination regardless of lighting environment.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If only measured hitch angle from sensor is used, then direct measurement is obtained, but errors and inaccuracies increase

Engineering Contradiction:

Improvedirect sensor measurementVSAvoidhitch angle accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the kinematic model continuously calculates an estimated hitch angle based on measured parameters (steering angle, vehicle speed, trailer speed), and this estimate is fed back to correct or supplement the direct sensor measurements. The system uses the model's calculation as feedback to compensate for sensor errors, improving overall measurement accuracy through iterative correction.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary calculation of the hitch angle through the kinematic model using easily measurable parameters before relying on or correcting with direct sensor measurements. By pre-calculating the expected hitch angle from steering angle and velocity measurements, the system has a reference value ready to correct sensor errors, improving accuracy proactively rather than reactively.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10173722B2System and method for determining a hitch angle based on an input from a sensor and a kinematic model of a vehicle and a trailer, and for controlling the vehicle based on the hitch angle

Publication Date: 2019.01.08 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A system according to the present disclosure includes an estimated hitch angle module, a measured hitch angle module, a corrected hitch angle module, and at least one of a driver assist module and an actuator control module. The estimated hitch angle module estimates a hitch angle, which is an angle between a longitudinal axis of a vehicle and a longitudinal axis of a trailer that is attached to the vehicle. The measured hitch angle module determines a measured hitch angle based on an input from a sensor. The corrected hitch angle module determines a corrected hitch angle based on the estimated and measured hitch angles. The driver assist module controls a user interface device to assist a driver of the vehicle based on the corrected hitch angle. The actuator control module controls an actuator of at least one of the vehicle and the trailer based on the corrected hitch angle.