Hydraulic Actuator Regeneration Control for Speed and Position Accuracy
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Solution Overview
Problem
Existing hydraulic excavators face a trade-off between position control accuracy and operation speed when using hydraulic fluid regeneration, where restricting the regeneration function to ensure accuracy results in reduced operation speed, leading to decreased work efficiency.
Innovation Solution
A work machine with a flow rate control valve and a regeneration valve system, controlled by a controller, that calculates and adjusts flow rates to balance the total hydraulic fluid supply with regeneration flow, ensuring both position control accuracy and increased operation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hydraulic fluid regeneration is performed to increase actuator operation speed, then the operation speed of the actuator is improved, but the position control accuracy deteriorates because the flow rate supplied to the actuator becomes higher than the target flow rate
Solution Approach 1:
The hydraulic system is segmented into two separate flow paths: a pump-side flow passage for supplying hydraulic fluid from the pump, and a tank-side flow passage for returning hydraulic fluid to the tank. The regeneration valve selectively merges these two paths, allowing regeneration flow to be added to the pump supply flow. This segmentation enables independent control of each flow path and their combination, resolving the contradiction by providing a mechanism to increase actuator speed through regeneration while maintaining control over the total flow rate supplied to the actuator.
Solution Approach 2:
The system dynamically changes the flow rate parameters by controlling the regeneration valve opening degree. The controller calculates the regeneration flow rate based on the difference between the target actuator flow rate and the pump supply flow rate, then adjusts the regeneration valve to achieve the desired total flow rate. This parameter adjustment allows the system to maintain position control accuracy while enabling speed enhancement through regeneration when conditions permit.
2Speed
If the flow rate of hydraulic fluid supplied from the pump to the actuator is increased to improve operation speed, then the operation speed is improved, but the position control accuracy deteriorates
Solution Approach 1:
The system merges the pump-side flow passage and tank-side flow passage through the regeneration valve to combine hydraulic fluid flows. By merging the return flow from the tank side with the supply flow from the pump side, the system increases the total flow rate to the actuator, thereby improving operation speed while maintaining position control accuracy through proper flow rate management.
Solution Approach 2:
The controller continuously monitors the target actuator flow rate and pump supply flow rate, calculates the required regeneration flow rate, and adjusts the regeneration valve accordingly. This feedback control mechanism ensures that the total flow rate supplied to the actuator matches the target flow rate, maintaining position control accuracy while enabling speed enhancement through regeneration.
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
The system allows for enhanced operation speed of actuators while maintaining precise position control, thereby improving work efficiency.
Implementation Method 1
a hydraulic pump that sucks a hydraulic working fluid from the hydraulic working fluid tank and supplies the hydraulic working fluid to the actuator
Implementation Method 2
a regeneration valve that allows a hydraulic working fluid to flow from the meter-out side to the meter-in side of the flow rate control valve
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Provided is a work machine which can increase the operation speed of an actuator by a regeneration function while securing the position control accuracy of the actuator. A controller is configured to calculate a regeneration flow rate on the basis of an input amount of an operation lever and a target actuator flow rate, subtract the regeneration flow rate from the target actuator flow rate to calculate a target actuator supply flow rate, calculate a target flow rate control valve opening amount on the basis of the target actuator supply flow rate, calculate a target pump flow rate that is equal to or higher than a total target actuator supply flow rate, control a selector valve on the basis of the input amount of the operation lever, control a flow rate control valve according to the target flow rate control valve opening amount, and control a hydraulic pump according to the target pump flow rate.