Hydraulic Actuator Startup Control for Shock and Flow Limiting
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Solution Overview
Problem
Existing working machine lifting devices face challenges in reducing shock during hydraulic actuator startup and balancing efficiency, as they struggle to effectively manage the drive speed and flow rate of hydraulic fluid to optimize both shock reduction and operational efficiency.
Innovation Solution
A working machine equipped with a controller that adjusts the drive speed and maximum flow rate of the hydraulic actuator based on a limit value, employing first and second control methods to optimize drive start conditions, using graphs to regulate current and flow rate adjustments for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drive speed of the hydraulic actuator is increased to improve work efficiency, then productivity increases, but shock occurs during drive startup
Solution Approach 1:
The controller performs preliminary action by gradually increasing the drive speed of the hydraulic actuator during the drive start period before reaching the target drive speed. This gradual acceleration prevents sudden shock while maintaining efficient operation once the target speed is achieved. The control method adjusts drive speed in advance during startup to eliminate harmful shock effects.
2Productivity
If the maximum flow rate of hydraulic fluid is increased to improve operational efficiency, then productivity increases, but shock and instability occur during drive startup
Solution Approach 1:
The controller dynamically adjusts the maximum flow rate of hydraulic fluid based on the drive start period conditions. During startup, the controller limits the maximum flow rate to prevent shock and instability, then increases it to achieve target operational efficiency. This dynamic control adapts the flow rate to current operating conditions, ensuring both stability and efficiency.
Solution Approach 2:
The controller performs preliminary control by adjusting the maximum flow rate before the hydraulic actuator reaches full operational capacity. During the drive start period, the controller preemptively limits flow rate increases to maintain stability, then allows full flow rate once stable operation is achieved, preventing shock while maintaining efficiency.
3Object-affected harmful factors
If the drive speed is limited to reduce shock, then shock reduction is achieved, but work efficiency decreases
Solution Approach 1:
The controller applies periodic action by implementing time-based control where drive speed and maximum flow rate are gradually increased during the drive start period. The control transitions from limited speed (for shock reduction) to target speed (for efficiency) over a predetermined time period, achieving both shock reduction and maintained efficiency through phased acceleration.
4Stability of the object's composition
If the maximum flow rate is limited to maintain stability, then drive stability is maintained, but operational efficiency decreases
Solution Approach 1:
The controller dynamically adjusts the maximum flow rate based on operational phase. During the drive start period, the controller maintains lower flow rates for stability, then transitions to higher flow rates for optimal efficiency once stability is established. This dynamic adaptation ensures both stability during transitions and efficiency during operation.
Solution Approach 2:
The controller implements periodic control by maintaining limited maximum flow rate during the drive start period for stability, then transitioning to unrestricted flow rate after the start period expires. This time-based phased approach ensures stability during critical startup phases while achieving full operational efficiency thereafter.
Data Source
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AI summary
A working machine (1) includes a drive device (8) including a hydraulic actuator (26) to be actuated by hydraulic fluid, and a controller (11) configured or programmed to change a drive speed of the drive device (8) in a drive start period. The controller (11) is configured or programmed to, if a limit value (V) based on which operation of the drive device (8) is limited is equal to or more than a threshold, perform a first control in which the controller (11) changes the drive speed of the drive device (8) in the drive start period based on the limit value (V), and if the limit value (V) is less than the threshold, perform a second control in addition to the first control, the second control being a control in which the controller (11) changes a maximum flow rate (MF) of hydraulic fluid to actuate the hydraulic actuator (26) based on the limit value (V).