Active Mass Damper for C-arm Vibration Suppression
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Solution Overview
Problem
C-arm imaging devices experience unintended residual motions such as vibrations and oscillations after commanded movements have stopped, which can negatively affect image quality by moving the image column with respect to the patient frame of reference.
Innovation Solution
An active mass damper system is integrated into the C-arm imaging device, comprising sensors to detect motion, a mass damper assembly with a linear motor and mass, and a controller that processes motion data to control the motor, moving the mass in a linear reciprocating path to provide a force that dampens unwanted motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a C-arm positioner is designed to move and articulate in various axes of motion, then the imaging device achieves positional flexibility and adaptability, but unintentional residual motions such as oscillations and vibrations occur after motions have been commanded to stop
Solution Approach 1:
The patent implements a dynamic damping system that adapts to the C-arm's motion state. The controller monitors position and velocity data, and dynamically adjusts the damper's characteristics (mass, stiffness, damping coefficient) based on the current operating conditions. This allows the system to provide optimal damping at different phases of motion, effectively suppressing residual oscillations while maintaining positional flexibility during intentional movements.
Solution Approach 2:
The patent changes the physical parameters of the damping system (mass value, spring stiffness, damping coefficient) based on the C-arm's operational state. The controller modifies these parameters in real-time to match the current motion characteristics, enabling the damper to effectively counteract residual vibrations at different frequencies and amplitudes while allowing intentional positional adjustments.
2Adaptability or versatility
If the C-arm position changes the center of gravity and loads the structure, then the resonant frequency of the C-arm changes, but this causes unpredictable oscillation frequencies
Solution Approach 1:
The patent employs a feedback control system where the controller continuously monitors the C-arm's position and velocity, and uses this information to adjust the damping parameters. The feedback loop detects changes in oscillation frequency caused by position changes and automatically adapts the damper characteristics to maintain effective vibration suppression across varying operational conditions.
Solution Approach 2:
The damping system is designed to be dynamic rather than static, with parameters that change in response to the C-arm's operational state. This dynamic adaptation allows the system to handle the varying resonant frequencies caused by different positions and load configurations, maintaining reliable vibration control throughout the range of motion.
3Stability of the object's composition
If an active mass damper system is added to dampen vibrations, then residual motions are reduced, but the device complexity increases
Solution Approach 1:
The patent designs the active mass damper system to serve multiple functions: it provides vibration damping, maintains positional stability, and adapts to varying operational conditions. By integrating the damping mechanism with the existing C-arm structure and control system, the patent reduces the need for separate dedicated damping components, thereby limiting the increase in overall system complexity.
Solution Approach 2:
The damping system is designed to be self-regulating, with the controller automatically adjusting parameters based on real-time position and velocity data. This self-service capability eliminates the need for external manual intervention or complex external control systems, reducing overall device complexity while maintaining effective vibration suppression.
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 active mass damper system effectively reduces undesired vibrations and oscillations, improving image quality by stabilizing the C-arm during and after movements, thus enhancing the overall performance of the imaging device.
Implementation Method 1
a mass damper assembly that includes a linear motor and a mass coupled to the linear motor
Implementation Method 2
control the linear motor, based on the filtered motion data and motor control tuning parameters, to move the mass in a linear reciprocating path to provide a force having a magnitude and a phase configured to dampen at least a portion of the motion of the C-arm
Data Source
AI summary
An active mass damper system includes one or more sensors configured to detect motion of a C-arm and output corresponding motion data representative of the motion of the C-arm. A mass damper assembly within the C-arm includes a linear motor, and a mass coupled to the linear motor. The active mass damper system further includes a controller configured to receive the motion data, process the motion data by applying one or more filters to the motion data to create filtered motion data, and control the linear motor, based on the filtered motion data and motor control tuning parameters, to move the mass in a linear reciprocating path to provide a force having a magnitude and a phase configured to dampen at least a portion of the movement of the C-arm.