Hydraulic Pump Torque Distribution for Multi-Joystick Excavator Control

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Solution Overview

Problem

Construction machines like excavators face challenges in distributing available torque effectively among hydraulic pumps to meet varying operational demands, leading to inefficient performance during complex operations where the sum of required torque exceeds available torque.

Innovation Solution

A construction machine with a control unit that adjusts the torque distribution ratio between multiple pumps based on the operation amounts of joysticks, increasing the distribution ratio to the pump supplying the actuator with the greater operation amount, and selecting an operation mode to ensure available torque does not exceed the engine's maximum output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the available torque is distributed to multiple hydraulic pumps using a fixed distribution ratio, then the system structure is simple and easy to control, but the torque distribution cannot meet varying operational demands leading to inefficient performance

Engineering Contradiction:
Improvetorque distribution adaptabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic torque distribution by continuously monitoring joystick operation amounts and automatically adjusting the torque distribution ratio between hydraulic pumps. The control unit calculates required torque based on real-time operation amounts and redistributes available torque dynamically, transforming the fixed distribution system into an adaptive one that responds to varying operational demands without requiring complex manual intervention

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms by detecting joystick operation amounts and using this information to adjust torque distribution. The control unit receives feedback from operation amount detection units, processes this information to determine required torque for each pump, and continuously optimizes the distribution ratio accordingly, enabling the system to adapt to changing operational conditions automatically

Inventive Principle:
Principle #23Feedback

2Productivity

If the torque distribution ratio is adjusted dynamically based on joystick operation amounts, then the operational efficiency is improved, but the control system becomes more complex

Engineering Contradiction:
Improveoperational efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The control system performs self-service by automatically detecting operation amounts, calculating required torque, and adjusting the distribution ratio without external intervention. The system monitors its own operational state through joystick position detection and autonomously optimizes torque allocation to maintain high productivity, reducing the need for complex external control mechanisms

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the torque distribution parameter dynamically based on detected operation amounts. The control unit adjusts the distribution ratio as a variable parameter rather than maintaining a fixed value, allowing the system to optimize operational efficiency by adapting the torque allocation parameter to match real-time operational demands

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the sum of required torque exceeds available torque during complex operations, then all operations can be performed simultaneously, but the torque deficiency causes slow or failed operations

Engineering Contradiction:
Improveoperation capabilityVSAvoidoperation reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system applies partial action by allocating torque prioritarily to operations with larger joystick operation amounts during torque-deficient conditions. Rather than distributing torque equally or limiting all operations, the control unit directs available torque to the most critical operations first, allowing essential functions to proceed reliably while less critical operations receive reduced torque

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The torque distribution system dynamically adjusts the distribution ratio based on real-time operation amounts to maintain operation reliability. When the sum of required torque exceeds available torque, the system continuously recalculates and redistributes torque according to current operational priorities, ensuring that critical operations maintain sufficient torque while adapting to changing conditions

Inventive Principle:
Principle #15Dynamics

4Ease of operation

If the torque is not appropriately distributed to hydraulic pumps, then the system structure remains simple, but the operations are performed slowly or cannot be performed

Engineering Contradiction:
Improveoperation smoothnessVSAvoidoperation speed
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The control system performs preliminary action by pre-calculating the required torque for each hydraulic pump based on detected joystick operation amounts before torque distribution. This advance calculation allows the system to prepare appropriate torque allocation strategies, ensuring smooth and timely torque delivery to meet operation speed requirements without causing delays

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3323946B1Construction machinery and method of controlling construction machinery
Publication Date: 2021.04.28 HD HYUNDAI INFRACORE CO LTD
  • EP3323946B1 patent drawingFigure 1(a)~1(c)
  • EP3323946B1 patent drawingFigure 2
  • EP3323946B1 patent drawingFigure 3

AI summary

Disclosed are a construction machine and a method of controlling a construction machine. The construction machine includes: a first pump and a second pump; an engine which provides available torque to the first pump and the second pump; a first joystick and a second joystick which control actuators operated by a working fluid discharged from the first pump and the second pump; a joystick operation amount acquiring unit which acquires operation amounts of the first joystick and the second joystick; and a control unit which adjusts a torque distribution ratio with respect to the first pump and the second pump in accordance with the operation amounts of the first joystick and the second joystick when a sum of required torque of the first pump and required torque of the second pump is higher than the available torque.