Work Vehicle Steering Gain Adaptation for Payload Variations

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Solution Overview

Problem

Existing automatic steering systems for agricultural vehicles do not effectively account for the variable payload, leading to inadequate steering performance and stability due to the sensitivity of steering reactions to the vehicle's mass, which can result in insufficient path following and stability issues.

Innovation Solution

An automatic steering system that adjusts its feedback gain based on the sensed payload of the vehicle, using a control unit to calculate and apply a payload-dependent steering signal to the steering actuator, ensuring a more responsive and stable steering reaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the feedback gain is kept constant in automatic steering systems, then the system structure remains simple, but the steering performance becomes insufficient when payload varies

Engineering Contradiction:
Improvesteering performanceVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The feedback gain is made dynamic by adjusting it according to the sensed payload of the vehicle. The control unit receives payload information from a payload sensor and modifies the feedback gain accordingly, allowing the steering system to adapt to varying mass conditions and maintain optimal steering performance throughout the vehicle's operational range.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the feedback gain parameter based on the detected payload. By monitoring the vehicle's mass through payload sensors and adjusting the feedback gain as a corresponding parameter, the system optimizes steering response without requiring a complete redesign of the control architecture.

Inventive Principle:
Principle #35Parameter changes

2Force

If the feedback gain is increased for vehicles with large payload, then the steering reaction becomes sufficient, but the steering reaction becomes too large for vehicles with small payload

Engineering Contradiction:
Improvesteering reactionVSAvoidsteering responsiveness
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The feedback gain parameter is dynamically adjusted based on the sensed payload. For vehicles with large payload, the feedback gain is increased to provide sufficient steering reaction force. For vehicles with small payload, the feedback gain is decreased to prevent excessive steering reaction, ensuring optimal ease of operation across all loading conditions.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the feedback gain is decreased for vehicles with high speed, then the steering stability is improved, but the steering reaction becomes insufficient for vehicles with low speed

Engineering Contradiction:
Improvesteering stabilityVSAvoidsteering reaction
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The feedback gain is dynamically adjusted based on both payload and speed conditions. The control unit modifies the feedback gain parameter to decrease it at high speeds for improved stability, while increasing it at low speeds to ensure sufficient steering reaction, creating a speed-dependent gain schedule that optimizes both stability and responsiveness.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1987710B1Automatic steering system and method for a work vehicle with feedback gain dependent on a sensed payload
Publication Date: 2018.06.13 DEERE & CO
  • EP1987710B1 patent drawingFigure 1
  • EP1987710B1 patent drawingFigure 2
  • EP1987710B1 patent drawingFigure 3

AI summary

An automatic steering system for a work vehicle (10) comprises a position sensor (38) for detecting a position of the vehicle (10), a memory (44) for storing information about a nominal path of the vehicle (10) and a control unit (40) coupled to the position sensor (38), to the memory (44) and to a steering actuator (42) for steering the vehicle (10). The control (40) submits control signals to the steering actuator (42) that depend upon a feedback gain and a lateral offset between the actual position and the nominal path. The feedback gain depends upon a sensed payload of the vehicle.