Remote Pressure Sensor Payload Estimation with Temperature Compensation
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Solution Overview
Problem
Existing payload measurement systems in loaders face inaccuracies and sensor damage due to the exposure of pressure sensors near hydraulic lift cylinders, which can be vulnerable to debris and water, leading to unreliable weight estimates.
Innovation Solution
A system that includes a pivotable lift linkage and a lift cylinder assembly connected to a remotely arranged pressure sensor, which monitors pressure data, temperature, and extension velocity, using a mathematical model to adjust for pressure drops and estimate payload weight accurately, even when sensors are not directly at the lift cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are arranged at the hydraulic lift cylinders to obtain accurate pressure data, then measurement precision is improved, but reliability deteriorates due to sensor exposure to debris and water
Solution Approach 1:
The system separates the pressure sensing function from the hydraulic cylinder location by placing pressure sensors remotely in protected positions. The pressure measurement function is segmented from the exposed hydraulic cylinder environment, allowing accurate pressure data collection while protecting sensors from debris and water damage.
Solution Approach 2:
The patent introduces an intermediary mathematical model that compensates for pressure drops between the remote pressure sensor location and the hydraulic cylinder. This model acts as a mediator, using temperature data, extension velocity data, and empirical relationships to calculate and compensate for pressure losses, thereby maintaining measurement precision despite the remote sensor placement.
2Reliability
If pressure sensors are located away from hydraulic lift cylinders to protect them from damage, then reliability is improved, but measurement precision deteriorates due to inaccurate pressure readings
Solution Approach 1:
The mathematical model serves as an intermediary that bridges the gap between remote pressure sensor readings and the actual pressure at the hydraulic cylinder. By incorporating temperature compensation and velocity-based pressure drop calculations, the model accurately reconstructs the cylinder pressure from remote sensor data, maintaining measurement precision while allowing sensor placement in protected locations.
Solution Approach 2:
The system changes the parameters used for pressure calculation by incorporating temperature data and extension velocity data into the pressure estimation process. Instead of relying solely on direct pressure readings, the system uses multiple parameters (temperature, velocity, and remote pressure) to compensate for pressure drops and maintain accurate payload weight estimates.
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 allows for accurate payload weight estimation while protecting sensors from environmental hazards, ensuring reliable and precise measurements by compensating for pressure drops based on temperature and velocity data.
Implementation Method 1
The payload measurement system is configured to estimate a weight of the payload in the bucket based on the pressure data as adjust by an estimate of a pressure drop between the lift cylinder assembly and the pressure sensor. The payload measurement system is configured to determine the estimate of the pressure drop based on the temperature data, the extension velocity data and a mathematical model that has been fitted to empirical data relating to pressure loss between the lift cylinder assembly and the pressure sensor at different hydraulic fluid temperatures and lift cylinder assembly extension velocities.
Data Source
AI summary
A system for estimating the weight of a payload in a bucket of a machine is provided. The system includes a lift linkage supporting the bucket and a hydraulic lift cylinder assembly connected to the lift linkage. A pressure sensor is arranged remotely from the lift cylinder assembly. A payload measurement system is configured to monitor pressure data from the pressure sensor, hydraulic fluid temperature data and cylinder extension velocity data. The payload measurement system estimates a weight of the payload in the bucket based on the pressure data as adjusted by an estimate of a pressure drop between the lift cylinder assembly and the pressure sensor, the estimate of the pressure drop being determined based on a mathematical model that has been fitted to empirical data.