Work Machine Attachment Properties via Boom Cylinder Pressure
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Solution Overview
Problem
Existing work machines, such as hydraulic excavators, require complex configurations and additional sensors to accurately calculate the weight and gravity center position of distal end attachments, leading to increased costs and potential sensor damage.
Innovation Solution
A work machine configuration that includes a boom, arm, distal end attachment, boom cylinder, arm cylinder, distal end cylinder, attitude detector, holding pressure detector, and a controller with a property calculation section. This setup allows for the calculation of the horizontal distance between the boom and arm, the weight of the distal end attachment at a pressure release position, and its gravity center position at a displacement position, without the need for pressure sensors on the bucket cylinder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are installed on both boom cylinder and bucket cylinder to calculate magnet weight and center of gravity, then measurement precision is improved, but device complexity increases and cost increases
Solution Approach 1:
The patent extracts the pressure sensor from the bucket cylinder location and relocates it to the boom cylinder location. This allows the sensor to still capture necessary pressure data for calculating attachment weight and center of gravity, but eliminates the need for multiple sensors and reduces system complexity.
Solution Approach 2:
The boom cylinder pressure sensor serves multiple functions: it measures boom cylinder pressure for standard operation control and simultaneously provides data for calculating attachment weight and center of gravity through the established calculation methods, eliminating the need for separate sensors.
2Measurement precision
If pressure sensors are disposed in the vicinity of distal end attachment such as bucket or lifting magnet, then measurement precision is improved, but reliability deteriorates due to sensor damage risk
Solution Approach 1:
The pressure sensor is extracted from the high-risk vicinity of the distal end attachment (bucket or magnet) and relocated to the boom cylinder location, which is mechanically protected and less susceptible to damage from drops, impacts, or environmental hazards at the working end of the excavator.
Solution Approach 2:
The patent uses the boom cylinder pressure as an intermediary measurement point. Instead of directly measuring pressure near the vulnerable distal end attachment, the system measures boom cylinder pressure and uses calculation based on mechanical principles to derive attachment properties, indirectly achieving the measurement goal while avoiding sensor exposure to harsh conditions.
3Measurement precision
If multiple pressure sensors are installed to accurately detect attachment properties, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The single boom cylinder pressure sensor performs multiple measurement functions, providing data for both standard hydraulic control operations and for calculating attachment weight and center of gravity, thereby eliminating the need for additional sensors and reducing overall system cost.
Solution Approach 2:
Instead of directly measuring attachment properties through multiple sensors placed on the attachment itself, the system creates a computational model that copies the measurement function using boom cylinder pressure data and mathematical calculations, achieving the same information goal with fewer physical components.
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
Enables the specification of the weight and gravity center position of distal end attachments with a simpler configuration, reducing costs and minimizing the risk of sensor damage, while maintaining accurate calculations.
Implementation Method 1
an attitude detector that detects attitudes of the boom, the arm, and the distal end attachment
Implementation Method 2
a holding pressure detector that detects a holding pressure of the boom cylinder
Implementation Method 3
a boom cylinder which is a hydraulic cylinder that operates so as to raise and lower the boom with respect to the machine body; an arm cylinder which is a hydraulic cylinder that operates so as to rotate the arm with respect to the boom
Data Source
AI summary
A property calculation section of the controller calculates a horizontal distance between a boom proximal end portion and an arm distal end portion based on a detection signal input from an attitude detector, calculates a weight of the distal end attachment based on the horizontal distance and a detection signal input from a holding pressure detector in a state where a distal end attachment is disposed at a pressure release position, and calculates a gravity center position of the distal end attachment based on the weight of the distal end attachment, a detection signal input from the holding pressure detector, and a detection signal input from the attitude detector in a state where the distal end attachment is disposed at a displacement position that is a position different from the pressure release position.