Harvester Saw Control Unit Adaptive Pressure Regulation

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Solution Overview

Problem

Harvesters for logging often operate with suboptimal configurations due to static settings, leading to inefficiencies and potential overloading of hydraulic systems, especially when cutting trees with varying densities and weather conditions.

Innovation Solution

A control unit that monitors pump pressure in a hydraulic system and adjusts saw pressure accordingly, decreasing pressure when overloaded and increasing it when underloaded, to maintain maximum efficiency and prevent system overload.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the harvester is configured with fixed parameters for sawing, then the configuration is simple and easy to operate, but the efficiency decreases when environmental conditions change

Engineering Contradiction:
Improveconfiguration simplicityVSAvoidsawing efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent implements dynamic configuration by allowing the harvester parameters (saw chain speed, saw pressure, actuator pressure) to be automatically adjusted based on real-time sensor measurements of tree properties. The control unit continuously adapts the configuration during operation, transforming the static system into a dynamic one that responds to environmental changes, thereby maintaining high efficiency without complicating operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms through sensors that measure tree properties (density, diameter, height) and provide this information to the control unit. The control unit processes this feedback and automatically adjusts the sawing parameters accordingly. This closed-loop feedback system enables the harvester to adapt to varying conditions while keeping the operator interface simple.

Inventive Principle:
Principle #23Feedback

2Productivity

If the saw chain speed is increased to maximum to improve efficiency, then productivity increases, but the risk of system overload and safety issues increases

Engineering Contradiction:
Improvesawing speedVSAvoidsystem safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of saw chain speed based on real-time measurements of tree properties and hydraulic system capacity. The control unit continuously optimizes the chain speed within safe limits, allowing maximum speed when the hydraulic system can support it, and reducing speed when approaching overload conditions. This dynamic control enables high productivity while maintaining system safety and reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system dynamically changes multiple parameters (saw chain speed, saw pressure, actuator pressure) based on measured tree properties and system capacity. By adjusting these parameters in coordination, the system achieves maximum efficient operation without overloading the hydraulic system, thereby maintaining both productivity and reliability.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the harvester adapts to different tree types and conditions to improve efficiency, then productivity increases, but the device complexity increases

Engineering Contradiction:
Improvesawing efficiencyVSAvoidsystem configuration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent uses automated feedback-based control where sensors measure tree properties and the control unit automatically adjusts configuration parameters. This eliminates the need for manual reconfiguration by operators, hiding the complexity of multiple parameters behind an automated system. The complexity is managed through software control rather than requiring complex manual adjustment mechanisms.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The harvester performs self-configuration by automatically measuring tree properties and adjusting its own parameters without external intervention. The control unit autonomously optimizes saw chain speed, saw pressure, and actuator pressure based on sensor data, enabling the system to adapt to different tree types while keeping the operator interface simple and the overall system manageable.

Inventive Principle:
Principle #25Self-service

4Productivity

If the saw pressure is increased to handle harder wood to maintain efficiency, then productivity is maintained, but the hydraulic system may become overloaded

Engineering Contradiction:
Improvesawing efficiencyVSAvoidhydraulic system load
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The patent dynamically adjusts saw pressure based on measured tree properties (density, hardness) and real-time hydraulic system capacity. The control unit coordinates changes in saw pressure with adjustments in saw chain speed and actuator pressure, optimizing the power distribution within the hydraulic system. This enables maintaining efficient sawing of hard wood without overloading the hydraulic system by balancing multiple parameters simultaneously.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3576519B1Control unit for a saw
Publication Date: 2025.01.08 ECO LOG SWEDEN
  • EP3576519B1 patent drawingFigure 1
  • EP3576519B1 patent drawingFigure 2
  • EP3576519B1 patent drawingFigure 3

AI summary

A control unit for controlling a saw in a harvester is provided. The saw is driven by a first hydraulic system and the saw is adapted to apply a saw pressure on a sawing area during sawing. The control unit comprises a sensor for measuring a pump pressure of the first hydraulic system. The control unit is configured to, in response to the pump pressure being above a first predetermined value, decrease the saw pressure applied by the saw during sawing, or, in response to the pump pressure being below a second predetermined value, increase the saw pressure applied by the saw during sawing. Further, a method and a system is provided.