Construction Machine Hydraulic Calibration for High-Velocity Actuator Mapping
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Solution Overview
Problem
Existing construction machines, such as hydraulic excavators, face challenges in accurately deriving the operation characteristics of hydraulic actuators at high velocities due to the dominance of inertia and viscous resistance, making precise control difficult and requiring multiple calibration operations.
Innovation Solution
A construction machine with a controller that adjusts the differential pressure across the meter-in valve during calibration, allowing indirect mapping of spool position to actuator velocity without high-speed actuator movement, thereby mitigating the influence of inertia and viscous resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the actuators are moved at high velocities to acquire measurement data in a high-velocity area, then the measurement data coverage is improved, but the influence of inertia and viscous resistance becomes dominant, deteriorating measurement precision
Solution Approach 1:
The patent introduces a computer as an intermediary device that generates simulated measurement data based on a physical model of the hydraulic actuator system. This simulated data serves as a mediator between the control system and the actual high-velocity operation characteristics, allowing the controller to learn and compensate for inertia and viscous resistance effects without requiring the actuator to physically operate at high velocities during calibration.
2Measurement precision
If the spool is accelerated for a long time to gradually accelerate the actuator, then the influence of inertia is reduced, but the limit of the movable range of the actuator is exceeded
Solution Approach 1:
The patent creates a virtual copy of the measurement data acquisition process by using a physical model to generate simulated measurement data. Instead of physically moving the actuator through its full range to capture high-velocity characteristics, the system copies the essential dynamic behavior through mathematical modeling and simulation, thereby avoiding the mechanical constraints of the actuator's physical movable range.
3Device complexity
If direct mapping of spool positions to actuator velocities is performed, then the calibration process is simplified, but accurate mapping in high-velocity areas cannot be achieved due to inertia and viscous resistance
Solution Approach 1:
The patent introduces simulated measurement data generated from a physical model as an intermediary layer between the spool position and actuator velocity mapping processes. This intermediary simulated data allows the system to perform comprehensive mapping including high-velocity characteristics without requiring complex physical calibration procedures, thus resolving the contradiction between process simplicity and mapping accuracy.
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 approach enables precise derivation of operation characteristics in high-velocity areas with reduced calibration operations, improving precision and efficiency.
Implementation Method 1
a pressure sensor that senses a differential pressure across the meter-in valve
Implementation Method 2
a velocity sensor for sensing an operation velocity of the hydraulic actuator
Implementation Method 3
a hydraulic pump that is driven by the prime mover, and delivers, as a hydraulic fluid, the hydraulic operating fluid sucked in from the tank
Implementation Method 4
a meter-in valve that adjusts a flow rate of the hydraulic fluid supplied from the hydraulic pump to the hydraulic actuator
Data Source
AI summary
A construction machine that precisely enables derivation of the operation characteristics of hydraulic actuators in a high-velocity area with less calibration operation is provided. A controller (10) has a calibration mode in which the controller (10) derives operation characteristics (α(xs)) representing a relation among a spool position (xs) of a meter-in valve (8a1), an operation velocity (Va) of a hydraulic actuator (4a), and a differential pressure (ΔP) across the meter-in valve (8a1), and is configured to, in a case where the spool position (xs) of the meter-in valve (8a1) has changed in a direction to increase the opening area of the meter-in valve (8a1) in the calibration mode, output a command signal to increase the opening area of a bleed-off valve (8b1) to a bleed-off solenoid proportional pressure-reducing valve (8b2) as a command signal to reduce the differential pressure (ΔP).