Hydraulic Pump Control Using Virtual Bleed Flow Compensation
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Solution Overview
Problem
Existing hydraulic control systems face challenges in accurately controlling the operation of actuators due to variations in discharge volume of pressurized oil caused by pressure conditions and load states within the hydraulic circuit, leading to deviations in actuator operations.
Innovation Solution
A hydraulic control device and method that includes a virtual bleed information output unit, a required bleed information output unit, a target control value determination unit, and a pump control unit to manage the hydraulic pump based on virtual and required bleed information, ensuring accurate control of the hydraulic circuit flow rate regardless of load states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the flow rate supplied to the hydraulic circuit is controlled taking into account the virtual bleed flow rate in advance, then energy conservation is improved, but the discharge volume of pressurized oil varies depending on pressure conditions and load state, causing actuator operation deviation
Solution Approach 1:
The control device calculates the virtual bleed flow rate in advance based on operation amount and stored virtual bleed characteristics, then determines the required pump discharge flow rate by adding this calculated bleed flow rate to the target actuator flow rate. This preliminary calculation compensates for future bleed losses, ensuring accurate actuator operation while maintaining energy efficiency.
Solution Approach 2:
The system uses discharge pressure detection to dynamically adjust the virtual bleed flow rate calculation. When discharge pressure exceeds a threshold, the detected pressure is used to recalculate the bleed flow rate, which is then added to the target flow rate to determine the required pump discharge flow rate, compensating for pressure-induced variations.
2Productivity
If the discharge flow rate of hydraulic pump is reduced to account for virtual bleed flow rate, then flow rate supplied to hydraulic circuit is suppressed for energy conservation, but actual actuator operation deviates from commanded operation due to discharge volume variation
Solution Approach 1:
The control device calculates the virtual bleed flow rate in advance based on operation amount and stored virtual bleed characteristics, then determines the required pump discharge flow rate by adding this calculated bleed flow rate to the target actuator flow rate. This preliminary calculation compensates for future bleed losses, ensuring accurate actuator operation while maintaining energy efficiency.
Solution Approach 2:
The system dynamically adjusts the pump discharge flow rate parameter based on operation amount, discharge pressure, and virtual bleed characteristics. The control device modifies the required discharge flow rate by adding the calculated bleed flow rate, ensuring consistent actuator performance across varying load conditions while optimizing flow rate efficiency.
Data Source
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AI summary
A hydraulic control device includes: a virtual bleed information output unit that outputs virtual bleed information 75 indicating a state of hydraulic oil flowing through a virtual bleed circuit based on an operation amount of an operation tool 35, a discharge pressure of a hydraulic pump 22, and a preset virtual bleed characteristic that is a characteristic of the virtual bleed circuit to which a control valve and a hydraulic oil tank are assumed to be connected by a bypass line; a required bleed information output unit that outputs required bleed information 77 indicating the state of hydraulic oil flowing through the virtual bleed circuit that is required to cause the hydraulic actuator to perform a desired operation based on the operation amount; a target control value determination unit that determines a target control value for the hydraulic pump 22 based on a comparison result between the virtual bleed information 75 and the required bleed information 77; and a pump control unit that controls the hydraulic pump 22 based on the target control value.