RC Vehicle Steering Stabilizer Using Dynamic Yaw Control

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Solution Overview

Problem

Current electronic steering stability systems for RC model vehicles disconnect the driver's input from the vehicle's response, particularly when counter-steering is activated, leading to an unnatural feel and instability, especially during turns and when driving on grades.

Innovation Solution

An Electronic Steering Stability (ESS) system utilizing 6-axis MEMS devices, optionally with a speed sensor, employs a feedback control system with PID error feedback to maintain the driver's intended yaw rate, incorporating a leaky integrator scheduler and anti-windup mechanisms to ensure smooth and responsive steering, even without a speed sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a driver assist strategy is used to hold heading constant by integrating yaw error rate, then heading stability is improved, but the system disconnects the driver's input from the vehicle response causing unnatural feel

Engineering Contradiction:
Improveheading stabilityVSAvoiddriver-vehicle connection feel
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The system dynamically switches between two control modes based on driving conditions: using integrated yaw error rate correction when steering input is near zero to maintain heading stability, and switching to direct yaw rate control when steering input exceeds a threshold to maintain natural driver-vehicle connection. This dynamic adaptation resolves the contradiction by applying the appropriate control strategy for each operating condition.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the control parameter from integrated yaw error rate to direct yaw rate based on the magnitude of steering input. When steering input is small, the system uses integrated correction to stabilize heading; when steering input is large, it switches to direct yaw rate control to preserve natural feel. This parameter change allows the system to optimize performance for different operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If counter-steering is applied to drive yaw rate to zero, then heading control is improved, but the system creates disconnect during turns reducing steering responsiveness

Engineering Contradiction:
Improveheading controlVSAvoidsteering responsiveness
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The system dynamically adjusts the control strategy based on steering input magnitude. For small steering inputs near zero, it applies integrated yaw error rate correction to maintain heading. For larger steering inputs during turns, it switches to direct yaw rate control that responds immediately to driver input, preserving steering responsiveness and natural feel during dynamic maneuvers.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control parameter changes from integrated correction to direct yaw rate control based on steering threshold. This parameter switch ensures that during turns when steering input is significant, the system prioritizes responsive driver input transmission over aggressive heading correction, maintaining natural steering feel and responsiveness.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If gain scheduling is used to minimize counter-steer, then driver connection is improved, but the system becomes complex with multiple control strategies

Engineering Contradiction:
Improvedriver connection feelVSAvoidcontrol system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The control system is segmented into two distinct modes based on steering input threshold: a low-input mode using integrated yaw error rate correction for heading stability, and a high-input mode using direct yaw rate control for natural feel. This segmentation simplifies the control logic compared to continuous gain scheduling by using clear threshold-based mode switching with distinct control strategies for each segment.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3283186B1Steering stabilizing apparatus for a model vehicle
Publication Date: 2019.05.22 TRAXXAS
  • EP3283186B1 patent drawingFigure 1~3
  • EP3283186B1 patent drawingFigure 4
  • EP3283186B1 patent drawingFigure 5

AI summary

An electronic system for stabilizing steering of a model vehicle may provide a curvature steering control of an RC vehicle. The approximate curvature control of the RC vehicle determined using error integration to achieve full steering. Application of a leaky integrator may be used to minimize steering memory. The leak factor may be based off gain scheduling of the steering input.