Load Cell Zero Reference Adjustment for Drift Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electric motor actuator systems, particularly in aircraft and large vehicle brake systems, the zero force value drifts over time due to external factors like shock and vibration, leading to inaccurate force feedback signals and potential safety issues.
Innovation Solution
A method and system that adjust the zero reference value of a load cell by retracting the actuator ram to a position where zero force is applied, measuring the force, calculating any offset, and using this offset to correct the zero reference value, thereby maintaining accurate force feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the load cell is used to sense force over time, then force feedback is provided, but the zero force value drifts leading to measurement inaccuracies
Solution Approach 1:
The system performs a preliminary action by retracting the ram to a known zero-force position and measuring the load cell output at this position. This preliminary measurement establishes a baseline zero reference that compensates for drift, allowing subsequent force measurements to be accurately referenced against this calibrated zero point rather than assuming the original zero remains valid.
Solution Approach 2:
The system implements feedback by continuously monitoring the load cell output and comparing it against the stored zero reference value. When drift is detected (difference between current zero measurement and stored reference), the system automatically adjusts subsequent force calculations by applying an offset compensation, ensuring accurate force feedback despite drift over time.
2Measurement precision
If the zero reference is adjusted frequently to maintain accuracy, then measurement precision improves, but system complexity and operation time increase
Solution Approach 1:
The system performs self-service by automatically executing the zero reference adjustment procedure without requiring external intervention. The controller autonomously retracts the ram to the zero position, measures the load cell output, calculates the offset, and applies compensation to subsequent measurements. This automation eliminates the need for manual calibration procedures while maintaining measurement precision.
Solution Approach 2:
The system implements periodic action by performing zero reference adjustments at predetermined intervals or under specific conditions (e.g., after power-up, after certain operating hours, or when drift thresholds are exceeded). This periodic recalibration maintains measurement accuracy without requiring continuous adjustment, balancing precision with operational efficiency.
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 stabilizes force feedback signals, improves system performance, simplifies force control algorithms, and enhances reliability by compensating for drift caused by external factors, reducing errors and uncommanded braking events.
Implementation Method 1
This actuation force loading may be sensed as strain measurement (e.g., indirectly) by a load cell
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system and method of adjusting a zero reference may comprise retracting ram (34) of an actuator (28) coupled to a load cell from a first position to a second position. The system and method may comprise reporting a measurement by a load cell, in response to the actuator (28) being in a second position. The system and method may comprise calculating a force being measured by the load cell. The system and method may comprise creating a zero reference offset value based on the calculation, in response to the force calculation resulting in a non-zero force calculation. The system and method may comprise adjusting a zero reference value of the load cell by the zero reference offset value.