MR-Compatible Ergometer Pneumatic Piston Air Cushion
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Solution Overview
Problem
Current ergometers suitable for use in magnetic resonance (MR) apparatus lack feedback control systems to maintain consistent resistance and are affected by frictional errors, leading to unreliable measurement results.
Innovation Solution
An ergometer with a pneumatic piston/cylinder system using compressed air and an air cushion to minimize friction, coupled with a computer-controlled pressure regulation system and external control module to maintain precise resistance and measurement accuracy, ensuring non-ferromagnetic components and minimal metal abrasion for MR compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional friction-based resistance mechanisms are used in ergometers, then resistance can be provided, but frictional losses cause non-linear measuring errors that falsify measurement results
Solution Approach 1:
The patent replaces traditional friction-based mechanical resistance with a pneumatic piston-cylinder system. Compressed air provides the resistance force through pressure differential across the piston, eliminating direct mechanical contact and associated friction. This pneumatic approach allows for linear, calculable resistance forces without the non-linear measuring errors caused by friction in conventional systems.
Solution Approach 2:
The invention substitutes a mechanical friction-based resistance mechanism with a pneumatic system. Instead of using friction between contacting surfaces to provide resistance, the system uses compressed air pressure acting on a piston to generate the resistance force. This substitution eliminates the harmful frictional effects while maintaining the ability to provide controllable resistance.
2Reliability
If feedback control systems are added to maintain consistent resistance, then measurement reliability improves, but device complexity increases
Solution Approach 1:
The pneumatic resistance system is designed to be inherently stable and self-regulating. The compressed air pressure naturally maintains consistent resistance without requiring active feedback control. The system's physical properties (gas pressure, piston area) provide automatic stability, eliminating the need for complex electronic feedback control systems while maintaining measurement reliability.
3Adaptability or versatility
If non-ferromagnetic materials are used for MR compatibility, then the ergometer can be operated in magnetic resonance apparatus, but manufacturing options are limited
Solution Approach 1:
The patent changes the material parameter from ferromagnetic to non-ferromagnetic materials to enable MR compatibility. This parameter change allows the ergometer to function in magnetic resonance environments without interference. The design accepts this material constraint and optimizes the pneumatic system and structural components accordingly, turning a limitation into a defining characteristic of the MR-compatible device.
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
The solution provides a reliable and precise measurement of work output by minimizing frictional losses and allowing for adjustable resistance, enhancing the accuracy of muscle function assessments in MR environments.
Implementation Method 1
friction loss has been minimized to a negligible value. Friction losses can essentially be avoided by providing a cushion, preferably an air cushion, in the piston/cylinder array between the piston and the cylinder at least during relative motion
Data Source
AI summary
The present invention relates to an ergometer which is particularly suitable for examining a test person or patient in a magnetic resonance apparatus. It comprises at least one drive means which is provided essentially movably and at least one pneumatic piston/cylinder array. The drive means is provided at the piston or the cylinder and pneumatically applied pressure between the piston and the cylinder constitutes a resistance or force to be overcome by the test person or patient by operating the drive means. The resistance or the force necessary to set the drive means in motion, particularly during operation, can be controlled and/or regulated and the piston and the cylinder are sized such that an air cushion is formed between them at least during operation or when they move relative to each other. The resistance or the force necessary to operate the drive means is regulated and/or controlled automatically or electronically based on measured signals from a feedback loop during the examination of the test person or patient.