Swing Hydraulic Circuit Control for Pressure and Coasting Speed
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Solution Overview
Problem
Current hydraulic control systems for swing mechanisms in hydraulic excavators lack velocity-based control and require additional hardware for pressure control, leading to increased costs and complex maintenance.
Innovation Solution
A software-based intelligent mode manager is implemented to switch between control modes, allowing for velocity-based control and pressure control without the need for additional hardware, by modeling the functionality of a balance valve in software.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional hardware (balance valve) is added for pressure control, then pressure control capability is improved, but device complexity and maintenance requirements increase
Solution Approach 1:
The patent replaces the mechanical balance valve with a software-based virtual balance valve implemented in the electronic control unit. The control unit models the balance valve functionality through software algorithms that calculate and regulate pilot pressure based on sensor inputs, eliminating the need for physical balance valve hardware while maintaining pressure control capability.
Solution Approach 2:
The patent creates a virtual copy of the balance valve functionality through software modeling in the control unit. This virtual balance valve replicates the pressure regulation function of the physical balance valve by using electronic sensors and control algorithms to simulate the mechanical valve's behavior, thereby maintaining the required pressure control without additional hardware.
2Measurement precision
If velocity-based control is implemented, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent implements velocity-based control through a feedback mechanism where the electronic control unit continuously receives input from sensors monitoring the actual swing mechanism velocity, compares it with the desired velocity, and adjusts the pilot pressure to the variable displacement pump accordingly. This closed-loop feedback system enables precise velocity control without requiring additional hardware beyond the existing sensors and control unit.
Solution Approach 2:
The patent achieves velocity-based control by dynamically changing the displacement parameter of the variable displacement pump based on velocity feedback. The control unit adjusts the pump displacement parameter in real-time to maintain the desired swing mechanism velocity, enabling precise control through parameter modulation rather than additional mechanical components.
3Loss of energy
If breaking energy recuperation is implemented, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The patent converts the harmful effect of breaking energy (energy waste during swing mechanism deceleration) into a beneficial resource by implementing energy recuperation. The system captures kinetic energy during swing mechanism deceleration through the hydraulic system and stores it in the hydraulic accumulator, converting what would be wasted energy into stored potential energy that can be reused for subsequent swing operations.
Solution Approach 2:
The patent implements energy recovery by capturing and storing breaking energy that would otherwise be discarded. During swing mechanism deceleration, the system recovers kinetic energy through the hydraulic circuit and stores it in the accumulator, allowing this energy to be recovered and reused for future swing operations rather than being lost.
4Device complexity
If software-based control is used instead of additional hardware, then device complexity is reduced, but control precision may be compromised
Solution Approach 1:
The patent replaces physical balance valve hardware with a software-based virtual balance valve in the electronic control unit. This substitution maintains control precision through sophisticated algorithms that calculate pilot pressure based on sensor feedback, while simultaneously reducing device complexity by eliminating the need for additional mechanical components.
Solution Approach 2:
The electronic control unit is designed to perform multiple functions: it serves as both the main control unit for pump displacement control and as a virtual balance valve for pressure control. This multi-functionality allows the system to maintain precision pressure control capabilities while reducing overall device complexity, as the same control unit handles both control tasks without requiring separate dedicated hardware.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces costs and maintenance by eliminating the need for additional hardware, while achieving velocity-based control and pressure control, including breaking energy recuperation, thereby improving the efficiency and reliability of the hydraulic control system.
Implementation Method 1
a hydraulic pump configured to supply the hydraulic motor with pressurized hydraulic fluid
Implementation Method 2
at least one variable displacement pump configured to supply the at least one hydraulic motor with pressurized hydraulic fluid
Data Source
AI summary
A closed-loop hydraulic circuit associated with a swing mechanism of a machine is controlled to obtain both a pressure control during acceleration and deceleration of the swing mechanism and a velocity control during coasting. In this manner, a system pressure in closed-loop hydraulic circuit is maintained below a maximum allowable pressure during acceleration and deceleration, and the swing mechanism can be rotated at a desired constant speed during coasting. This is achieved by controlling a hydraulic actuator adjusting the displacement of a variable displacement pump in different control modes, depending on a comparison between a desired displacement of the pump and an actual displacement of the same.