Excavator Boom Control Lever Vibration Suppression
Solution Overview
Problem
Hydraulic excavators experience minute vibrations in the control lever during boom-lowering operations due to abrupt fluctuations in pilot pressure outputted by the pilot pressure control valve, causing discomfort to the operator.
Innovation Solution
The implementation of a hydraulic excavator system with a controller that adjusts the opening degree of boom-raising and boom-lowering proportional solenoid valves to minimize fluctuations in hydraulic oil pressure, ensuring the boom is raised or lowered smoothly, thereby reducing vibrations in the control lever.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the pilot pressure control valve operates with abrupt pressure fluctuations to enable responsive boom-lowering control, then the responsiveness of boom control is improved, but minute vibrations occur in the control lever causing operator discomfort
Solution Approach 1:
The controller predicts future pilot pressure based on past and present pressure values using proportional integration differentiation (PID) control, and outputs a predicted current value to the proportional solenoid valve in advance. This preliminary action prevents abrupt pressure fluctuations before they occur, thereby suppressing control lever vibrations while maintaining responsive boom control.
Solution Approach 2:
The system implements feedback control by continuously monitoring pilot pressure through the pressure sensor, comparing it with target values, and adjusting the proportional solenoid valve current accordingly. The PID controller uses feedback from past and present pressure readings to predict future pressure states and make corrective adjustments, eliminating vibrations while preserving control responsiveness.
2Speed
If the proportional solenoid valve opens rapidly to enable quick boom-lowering operation, then the operation speed is improved, but pressure fluctuations increase causing control lever vibrations
Solution Approach 1:
The PID controller calculates predicted current values for the proportional solenoid valve based on anticipated pressure requirements, enabling smooth valve opening without abrupt pressure changes. This preliminary calculation ensures the valve opens at an optimized rate that maintains both speed and pressure stability.
Solution Approach 2:
The system dynamically adjusts the proportional solenoid valve current based on real-time pressure conditions and predicted future states. The PID control continuously modifies the current output to maintain optimal valve opening speed while preventing pressure fluctuations, adapting to changing operational conditions.
3Productivity
If the controller uses aggressive current increase to the proportional solenoid valve for rapid boom response, then the productivity is improved, but control lever vibrations increase reducing operator comfort
Solution Approach 1:
The PID controller predicts future current requirements based on pressure trends, allowing the system to prepare optimal current values in advance. This enables rapid boom response for high productivity while avoiding abrupt current changes that cause vibrations and reduce operator comfort.
Solution Approach 2:
The system uses feedback from pressure sensors to continuously adjust proportional solenoid valve current, comparing actual pressure with target pressure and making real-time current adjustments. This feedback mechanism maintains high operational efficiency while suppressing vibrations to ensure operator comfort.
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 effectively suppresses minute vibrations in the control lever, enhancing operator comfort and improving the efficiency and quality of land leveling work by maintaining precise control over the boom's movement.
Implementation Method 1
a boom-raising proportional solenoid valve; a boom-lowering proportional solenoid valve
Implementation Method 2
The pressure sensor detects a pressure generated in the boom-lowering pilot conduit
Implementation Method 3
controls operation of the boom... controls an opening degree of the boom-lowering proportional solenoid valve based on the pressure detected by the pressure sensor
Data Source
AI summary
There is provided a hydraulic excavator in which occurrence of minute vibrations in a control lever can be suppressed. A boom-raising proportional solenoid valve is provided in a boom-raising pilot conduit. A boom-lowering proportional solenoid valve is provided in a boom-lowering pilot conduit. A controller controls an opening degree of the boom-lowering proportional solenoid valve based on a pressure generated in the boom-lowering pilot conduit between the control lever and the boom-lowering proportional solenoid valve, and controls an opening degree of the boom-raising proportional solenoid valve. An amount of increase in current per unit time when the controller outputs, to the boom-lowering proportional solenoid valve, an instruction signal for instructing an increase in opening degree is smaller than an amount of increase in current per unit time when the controller outputs, to the boom-raising proportional solenoid valve, an instruction signal for instructing an increase in opening degree.