Medical Scale Calibration Using Stable Actuator Force Control
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Solution Overview
Problem
Calibration of medical scales is labor-intensive, time-consuming, and costly, and existing calibration devices suffer from force decay issues, limiting accuracy and efficiency.
Innovation Solution
A system and method using an actuator controlled by an electronic processor to apply and maintain a target force value for precise scale calibration, with hysteresis processes to stabilize the applied force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration reference weights are used, then measurement accuracy is improved, but labor intensity and time consumption increase significantly
Solution Approach 1:
The patent replaces the manual mechanical process of placing and removing reference weights with an automated actuator system. The actuator applies calibrated forces directly to the scale platform, eliminating the need for physical weight handling while maintaining measurement accuracy. This substitution of mechanical operations with an automated control system resolves the contradiction between precision and productivity.
Solution Approach 2:
The calibration system performs self-calibration by automatically applying known forces through the actuator and measuring the scale's response. The system uses its own actuator and control mechanisms to generate calibration signals without requiring external reference weights or manual intervention, thereby improving both accuracy and efficiency simultaneously.
2Measurement precision
If reference weights are transported to each location, then calibration accuracy is improved, but transportation cost and complexity increase
Solution Approach 1:
The patent extracts the calibration function from the physical reference weights and embeds it within the portable actuator device. Instead of transporting heavy reference weights to each calibration location, the actuator contains the calibration capability internally by generating precise forces through its motor and mechanism. This extraction eliminates transportation requirements while maintaining field calibration accuracy.
Solution Approach 2:
The actuator device serves multiple functions: it can apply calibration forces at various magnitudes, operate at different locations without reference weights, and calibrate multiple scale types. This multi-functionality replaces the need for location-specific reference weight sets, reducing overall system complexity while maintaining calibration precision across diverse field conditions.
3Measurement precision
If calibration force is applied for extended period to account for decay, then measurement accuracy is improved, but calibration time increases significantly
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the applied force through load cells and compares it against the target calibration force. When decay is detected, the control system automatically adjusts the actuator output to maintain the correct force level. This real-time feedback eliminates the need for extended waiting periods, as the system actively compensates for decay during the calibration process, maintaining accuracy while reducing calibration time.
Solution Approach 2:
The system applies a preliminary force greater than the target calibration force before the actual calibration measurement. This preliminary action pre-loads the mechanical components, reducing subsequent decay during the measurement phase. By performing this preparatory action beforehand, the system minimizes force drift during calibration without requiring extended waiting times, thus improving both accuracy and time efficiency.
4Adaptability or versatility
If higher calibration range is needed, then scale versatility is improved, but reference weight transportation difficulty increases
Solution Approach 1:
The patent employs a dynamic actuator system that can generate variable forces across a wide range, replacing static reference weights. The actuator's motor and control system allow it to adaptively produce any required calibration force within its capability, enabling calibration of scales across different ranges without changing physical components. This dynamic capability improves versatility while maintaining ease of operation, as the same device handles all calibration ranges through electronic control rather than manual weight selection.
Data Source
AI summary
Systems and methods for scale calibration. One example embodiment provides a system for calibrating a scale. The system may generally include an actuator for applying force to a platform of the medical scale, and an electronic processor communicatively coupled to the actuator. The electronic processor may be configured to control an actuator to apply, for a first interval, a first applied force having a first value greater than a target force value, and control the actuator to apply, for a second interval, a second applied force having a second value substantially equal to the target force value.