Torque Limit Control for Medical Insertion Apparatus
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Solution Overview
Problem
Existing rotary self-propelled insertion apparatuses lack effective torque control mechanisms, leading to inefficient propulsion and potential damage during insertion and removal procedures in luminal environments.
Innovation Solution
Incorporating a motor control system with a torque limit determining section that uses a moving average of motor current to compare against a predetermined torque limit, allowing for controlled motor operation and preventing excessive torque, thereby aiding in safe and efficient self-travel within lumens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a motor is used to rotate the rotary cylinder for self-propulsion, then the insertion apparatus can autonomously travel through lumens, but excessive torque may damage luminal structures
Solution Approach 1:
The motor control section continuously monitors motor current as a proxy for torque and dynamically adjusts motor output based on real-time feedback. When the moving average of motor current exceeds the torque limit threshold, the system automatically reduces torque to prevent damage to luminal structures while maintaining propulsion capability during normal operation
Solution Approach 2:
The system dynamically changes the motor operating parameters by adjusting the motor current based on the calculated moving average. The motor control section modifies current supply in real-time to maintain torque within safe limits, transforming the motor operation from fixed-parameter to adaptive-parameter control
2Reliability
If torque control is implemented by monitoring instantaneous motor current, then rapid torque limits can be enforced, but the system may be overly sensitive to transient current spikes
Solution Approach 1:
The system performs preliminary smoothing of the motor current signal by calculating a moving average over a predetermined number of cycles before comparing it to the torque limit threshold. This preliminary action filters out transient spikes and noise, allowing the system to respond to sustained torque violations while ignoring momentary fluctuations
Solution Approach 2:
The torque monitoring operates periodically by sampling motor current at regular intervals and computing the moving average across multiple periods. This periodic sampling approach provides stable torque control by averaging over time, reducing the impact of transient variations while maintaining reliable detection of sustained torque violations
Data Source
AI summary
An insertion apparatus includes an inserting section, a rotary cylinder, a motor, motor control section, a moving average calculating section, and a torque limit determining section. The inserting section is formed along a longitudinal axis. The rotary cylinder is provided to be rotatable around a longitudinal axis of the inserting section. The motor rotates the rotary cylinder. The motor control section supplies a motor current to drive the motor. The moving average calculating section calculates an average of the motor current within a predetermined period, after the motor starts up. The torque limit determining section determines whether torque of the motor is in a limit state by comparing a calculating result by the moving average calculating section with a predetermined torque limit set value, at timing except startup of the motor.