Cable-Driven 6-DOF Soft Robot for Ultrasound Probe Control
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Solution Overview
Problem
Existing soft robots for ultrasound imaging have limited degrees of freedom (DOF) and cannot effectively control both the position and orientation of the ultrasound probe, leading to limited maneuverability and safety concerns during clinical procedures.
Innovation Solution
A 6 DOF soft robot with flexible links and soft actuators, inspired by the Stewart mechanism, is designed to provide precise positioning and orientation control of the ultrasound probe, using a joystick controller and electromagnetic tracking for safe and intuitive operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single soft arm structure is used, then the robot is soft and compliant for patient safety, but the positioning accuracy and output force are limited
Solution Approach 1:
The robot is divided into multiple independent soft arms (typically three) instead of a single soft arm. Each arm can be independently actuated and controlled, allowing the system to achieve higher positioning accuracy and output force through coordinated motion while maintaining soft compliance for patient safety
Solution Approach 2:
Multiple soft arms are merged into a parallel configuration where they work together to control the ultrasound probe. The combined effect of multiple arms provides enhanced positioning accuracy and force output while the soft material composition maintains patient safety
2Measurement precision
If a parallel structure is used, then the blocking force and positioning accuracy are improved, but the system only has 3 DOF and suffers from limited maneuverability
Solution Approach 1:
The robot transitions from a static 3-DOF parallel structure to a dynamic 6-DOF system by adding active articulation at the end effector. The end effector can dynamically adjust its orientation independently of the arm positions, providing full maneuverability for ultrasound imaging while maintaining the positioning accuracy benefits of the parallel structure
3Device complexity
If existing soft robots with limited DOF are used, then the structure is simple and soft, but they cannot control both position and orientation of the ultrasound probe
Solution Approach 1:
The control system is segmented into two independent parts: the parallel arm mechanism for position control and the articulated end effector for orientation control. This segmentation allows the system to achieve full 6-DOF control capability while maintaining relatively simple individual components that can be manufactured with soft materials
Data Source
AI summary
An apparatus is described for robotic control of an ultrasound imaging device. The apparatus comprises a fixed base and a movable platform with an end-effector. A plurality of passive soft links connects the platform to the base. A series of cables connect the platform to a set of motors adjacent the base. When the platform is at rest, the tension in the cables counter-balances the passive soft links pushing the platform away from the base plate. Control electronics move the motors so as to control the location and the orientation of the platform. By increasing or decreasing tension in the cables, the motors smoothly control the location and the orientation of the platform and thus the end effector. Such a robotic apparatus can be used to provide expert handling of an ultrasound imaging device remotely.