Working Hydraulics Overload Detection via Motor Power
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Solution Overview
Problem
Working machines like wheel loaders can experience dangerous overload situations due to bucket or fork overloading, leading to loss of control or tipping over, and existing solutions require additional sensors for weight measurement.
Innovation Solution
A method that estimates load on working hydraulics using actual motor power consumption of an independent motor drive, compares it with a critical threshold, and provides a warning signal or control command to prevent overload, without the need for additional pressure sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional pressure sensors are used to measure load on working hydraulics, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The independent motor drive serves dual purposes: powering the hydraulic pump and simultaneously providing load measurement data through its existing power consumption sensors. The motor controller already measures current and voltage for power management, which are directly used to calculate hydraulic load, eliminating the need for separate measurement systems.
Solution Approach 2:
The patent replaces mechanical pressure sensors with an electrical measurement approach. By measuring the electrical power consumption of the hydraulic motor and relating it to the hydraulic load through the motor controller, the system substitutes direct mechanical pressure measurement with indirect electrical measurement, reducing sensor requirements.
2Reliability
If additional pressure sensors are installed for weight measurement, then safety is improved, but manufacturing cost increases
Solution Approach 1:
The motor drive system provides its own safety monitoring function by utilizing its existing power consumption measurement capabilities. The motor controller continuously monitors electrical parameters to detect overload conditions, making the system self-monitoring without requiring additional safety sensors or systems.
Solution Approach 2:
The motor controller performs multiple functions: power management of the hydraulic motor, efficiency optimization, and safety monitoring through load estimation. This multi-functionality consolidates what would traditionally require separate systems into a single integrated controller, reducing overall system cost.
3Device complexity
If load estimation uses motor power consumption data, then device complexity is reduced, but measurement precision may be affected
Solution Approach 1:
The motor controller continuously monitors electrical parameters (current, voltage, power) and uses this feedback to dynamically estimate the hydraulic load. This real-time feedback mechanism allows the system to track load changes accurately despite using indirect measurement, compensating for variations in operating conditions.
Solution Approach 2:
The system changes the measurement parameter from direct mechanical pressure to electrical power consumption. By measuring electrical parameters that are directly related to the motor's mechanical output, the system achieves accurate load estimation through a different physical domain, maintaining precision while reducing complexity.
Data Source
Figure 1~2
AI summary
The invention relates to a method for operating a working machine with working hydraulics comprising a pump, the working machine further comprising an independent motor drive for powering the working hydraulics comprising the steps estimating a load on the working hydraulics based on a load estimation model using an actual motor power consumption of the independent motor drive, comparing the estimated load with a critical threshold, if the estimated load is above the critical threshold providing a warning signal or a control command stopping an actual movement.