Hydraulic Actuator Control Using Virtual Throttle Feedback
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Solution Overview
Problem
Existing hydraulic control systems for excavators waste energy due to continuous hydraulic fluid leakage through throttle apertures, and struggle to efficiently drive high-capacity actuators connected to multiple manifolds, lacking optimal energy efficiency and feedback response to operator commands.
Innovation Solution
A hydraulic apparatus and method that independently vary the flow rate to or from multiple manifolds by controlling the net displacement of working chambers and actuator valves, simulating the presence of leakage without actual throttled outlets, allowing for energy-efficient operation and operator feedback similar to traditional systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional Negacon control process with throttled aperture is used, then operator feedback and actuator response are maintained, but energy is wasted due to continuous hydraulic fluid leakage
Solution Approach 1:
The patent creates a virtual copy of the throttled outlet aperture through software simulation. The control system calculates what the manifold pressure would be if a physical throttle aperture existed, based on pump displacement, actuator demands, and system characteristics. This virtual model replicates the pressure-regulating function of the physical aperture without causing actual fluid leakage, thereby eliminating energy waste while preserving operator feedback.
Solution Approach 2:
The patent replaces the mechanical throttle aperture with an electronic control system. Instead of using a physical restricted opening to regulate pressure and provide feedback, the system uses sensors, processors, and actuators to calculate and control pump displacement electronically. This substitution eliminates the continuous fluid flow through the aperture while maintaining the control characteristics operators are familiar with.
2Productivity
If standard hydraulic arrangement with separate manifolds is used, then multiple actuators are controlled, but high capacity actuators cannot be optimally driven
Solution Approach 1:
The patent makes the hydraulic system more versatile by enabling a single manifold to serve multiple functions. The system can dynamically allocate pump capacity to different actuators based on demand, and the virtual aperture control allows high-capacity actuators to receive optimized flow rates without requiring separate dedicated manifolds. This multi-functional approach eliminates the need for complex multi-manifold configurations while maintaining the ability to drive high-capacity actuators efficiently.
Solution Approach 2:
The patent introduces dynamic control to the hydraulic system. Instead of fixed manifold configurations, the system continuously adjusts pump displacement based on real-time actuator demands. The virtual aperture pressure calculations are dynamically updated, allowing the system to optimize performance for high-capacity actuators on demand rather than requiring permanent complex infrastructure.
3Reliability
If throttled aperture is used for pressure control, then negative control is achieved, but continuous fluid flow causes energy loss
Solution Approach 1:
The patent creates a virtual replica of the throttled aperture's pressure control function. The control system calculates the pressure that would exist at a virtual restricted opening based on pump output, actuator flow demands, and system resistance characteristics. This calculated virtual pressure is then used for negative feedback control of pump displacement, achieving reliable pressure control without the energy-wasting continuous fluid flow through a physical aperture.
Solution Approach 2:
The patent implements an enhanced feedback control system. Sensors monitor actual manifold pressure, actuator positions, and pump displacement. The processor compares measured pressure with calculated virtual aperture pressure and adjusts pump displacement accordingly. This feedback loop achieves reliable pressure control while eliminating the continuous fluid leakage inherent in traditional throttled aperture systems.
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 approach enhances energy efficiency by eliminating unnecessary fluid leakage and provides a responsive actuator control system that mimics traditional hydraulic circuits, offering improved control and feedback without the energy wastage associated with throttle apertures, while effectively managing high-capacity actuators.
Implementation Method 1
a hydraulic pump delivers working fluid to a first and second hydraulic circuit manifold
Implementation Method 2
The hydraulic machine comprises a plurality of working chambers having a volume which varies with rotation of a rotatable shaft
Data Source
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AI summary
A hydraulic apparatus comprises first and second manifolds each of which is connected to a plurality of actuators via corresponding actuator valves connected in parallel and operated responsive to inputs to regulate the flow of fluid to the actuators. A plurality of working chambers are connectable to either the first or second manifold and have a net flow which is controlled responsive to a negative feedback signal. The negative feedback signal is determined in response to a calculated pressure or flow rate in virtual fluid flow paths extending from the first and second manifolds.