Excavator Boom-Arm Hydraulic Speed Coordination on Sloped Surfaces
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Solution Overview
Problem
Construction equipment, such as excavators, face challenges in controlling the speed of booms and arms effectively, particularly when considering the angle of the arm relative to the work surface, the moment of inertia of the work machine, and engine output, leading to issues like the boom not keeping up with the arm's movement, especially on inclined surfaces and during high-load operations.
Innovation Solution
The implementation of an electronic control unit that adjusts the arm speed increase rate based on the speed required for driving the boom, moment of inertia, and engine output, using an electronic proportional pressure reducing valve and an information providing unit to calculate and output pilot pressure, ensuring the boom can be lifted or lowered in sync with the arm's movement by adjusting hydraulic oil flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the boom speed is increased to keep up with arm movement, then the productivity is improved, but the control precision deteriorates due to not considering moment of inertia and engine output constraints
Solution Approach 1:
The control system dynamically adjusts the arm speed increase rate based on real-time operating conditions including moment of inertia and engine output. The electronic control unit continuously monitors these parameters and modifies the speed control characteristics accordingly, transitioning from static to dynamic control to achieve both high productivity and precise speed control.
Solution Approach 2:
The system changes the arm speed increase rate parameter based on operating conditions. When the moment of inertia is within a predetermined range and engine output is sufficient, a higher arm speed increase rate is applied to boost productivity. When conditions are unfavorable, the rate is reduced to maintain control precision, thus dynamically optimizing the parameter.
2Productivity
If the arm speed increase rate is set high, then the productivity is improved, but the reliability deteriorates when moment of inertia is large or engine output is insufficient
Solution Approach 1:
The control system incorporates feedback mechanisms that continuously monitor the moment of inertia and engine output. Based on this feedback, the electronic control unit adjusts the arm speed increase rate to ensure reliable operation. When feedback indicates high moment of inertia or insufficient engine output, the system automatically reduces the speed increase rate to maintain control reliability.
Solution Approach 2:
The arm speed increase rate is not fixed but dynamically adjusted based on real-time system state. The control system adapts the parameter according to changing operating conditions, ensuring high productivity when conditions permit and maintaining reliability when conditions are challenging.
3Productivity
If the boom speed is increased without considering work surface angle, then the productivity is improved, but the operational safety deteriorates by invading or escaping the work surface
Solution Approach 1:
The control system performs preliminary calculations to determine the required boom speed based on the arm angle with respect to the work surface before executing the movement. By pre-calculating the appropriate speed parameters considering the work surface geometry, the system ensures both high productivity and operational safety, preventing the boom from invading or escaping the work surface.
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 improves the reliability of arm speed control by ensuring the boom can be lifted or lowered in accordance with the arm's movement in various situations, enhancing operational efficiency and preventing the boom from invading or escaping the work surface.
Implementation Method 1
an electronic proportional pressure reducing valve for controlling the spool of the control valve
Implementation Method 2
a work machine which comprises a boom, an arm, and a bucket operated by their respective hydraulic cylinder
Data Source
AI summary
A construction equipment includes a lower traveling body; an upper rotating body rotatably supported on the lower traveling body; a work machine which includes a boom, an arm, and a bucket operated by their respective hydraulic cylinder, wherein the work machine is supported by the upper rotating body; a control valve for controlling the hydraulic cylinder; an electronic proportional pressure reducing valve for controlling the spool of the control valve; an operation lever for outputting an operation signal corresponding to an operation amount of a driver; an information providing unit for providing information on the work machine and the work surface; and an electronic control unit for calculating and outputting a pilot pressure for the electronic proportional pressure reducing valve, wherein the electronic control unit controls the speed of the hydraulic cylinder by using the operation signal of the operation lever and the information provided by the information providing unit.