Articulated Arm Stabilizer for Vibration Reduction
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Solution Overview
Problem
Computer-assisted medical devices with articulated arms face challenges in stabilization and vibration reduction, especially in minimally invasive procedures where the body wall provides insufficient support, leading to precision and accuracy issues due to oscillations and vibrations.
Innovation Solution
An arm stabilizer system comprising a spine with vibration-absorbing mounts and clamps that connect and stabilize two articulated arms, forming a closed kinematic chain to reduce vibrations and improve precision by grounding the masses of the arms and supporting the remote center of motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the articulated arm is made longer to reach distant targets, then the working range is improved, but the vibrations and oscillations increase
Solution Approach 1:
A counterweight is introduced as an intermediary mass between the articulated arm and the base. This counterweight acts as a mediator that generates opposing forces to balance the arm's motion, thereby reducing vibrations and oscillations at the distal end while maintaining the arm's extended length for reaching distant targets.
Solution Approach 2:
The system changes the mass distribution parameter by adding a counterweight with specific mass and position. This parameter change creates a balancing effect that reduces the harmful vibrations and oscillations caused by the long articulated arm's motion, allowing the arm to maintain its extended length without excessive vibration.
2Force
If the mass of the end effector is increased to improve gripping force, then the holding capability is improved, but the vibrations and oscillations of the articulated arm increase
Solution Approach 1:
A counterweight is positioned on the articulated arm structure to create a balancing effect against the heavy end effector. This counterweight generates opposing forces that compensate for the inertia and gravitational effects of the massive end effector, thereby reducing vibrations and oscillations while maintaining the high gripping force capability.
3Power
If the actuator size is increased to provide more force and torque, then the force capability is improved, but the device complexity and space requirements increase
Solution Approach 1:
The counterweight balances the loads on the articulated arm, reducing the net force and torque requirements of the actuators. This allows the use of smaller, less complex actuators while still achieving the necessary force and torque capabilities for precise medical procedures.
4Adaptability or versatility
If the articulated arm operates without body wall constraints to access difficult anatomical regions, then the adaptability is improved, but the stability and precision decrease
Solution Approach 1:
The counterweight acts as an intermediary that provides stabilizing forces to the articulated arm system. This mediator enables the arm to maintain stability and precision even when operating in difficult anatomical regions without the stabilizing effect of body wall constraints.
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 arm stabilizer system effectively reduces vibrations and enhances precision and accuracy of the articulated arms, allowing for more reliable port placements and motion control, even in procedures without body wall constraints, by stabilizing the remote center of motion and minimizing friction.
Implementation Method 1
a first vibration absorbing mount attached to the spine, a second vibration absorbing mount attached to the spine
Data Source
AI summary
A computer-assisted medical device includes a first articulated arm, a second articulated arm, an arm stabilizer, and a control system. The arm stabilizer includes first and second clamps and one or more sensors. The first and second clamps are configured to couple the arm stabilizer to the first and second articulated arms. At least one of a distance or a relative orientation between the first and second clamps is adjustable and the one or more sensors are configured to determine the distance or relative orientation. The control system is configured to implement a following mode in which the control system drives movement of the second articulated arm in response to movements of the first articulated arm and the arm stabilizer.