Offset Remote Center Manipulator Linkage for Surgical Robots
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Solution Overview
Problem
Current minimally invasive robotic surgical systems face limitations in range of motion, complexity, size, and physical weight, which hinder efficiency and ease of use during minimally invasive robotic surgery.
Innovation Solution
The development of an offset remote center manipulator with an articulate linkage assembly that includes a parallelogram linkage base and angularly offset links, allowing for greater motion along yaw and pitch axes while maintaining alignment through a center of rotation, thus enhancing the range of motion and reducing system complexity and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional parallelogram manipulator structure is used to constrain instrument movement, then the center of rotation can be aligned with the incision point, but the range of motion is limited and the system complexity, size, and weight increase
Solution Approach 1:
The manipulator is divided into multiple modular components: a parallelogram linkage mechanism for maintaining remote center constraints, a decoupled actuation system with separate motors for pitch and yaw control, and a segmented instrument holder assembly. This segmentation allows each component to be optimized independently, reducing overall system complexity while enabling enhanced range of motion through coordinated operation of the modules.
Solution Approach 2:
The invention introduces an additional degree of freedom by allowing the parallelogram linkage base to rotate about a first axis (yaw axis) in addition to the traditional pitch axis rotation. This dimensional extension enables the instrument to achieve motion in multiple directions while maintaining the remote center constraint, thereby increasing the range of motion without proportionally increasing system complexity.
2Adaptability or versatility
If the parallelogram linkage base is rotationally coupled to allow rotation about a first axis, then the range of motion along yaw and pitch axes is enhanced, but the physical weight of the manipulator increases
Solution Approach 1:
The manipulator employs dynamic actuation where motors are selectively engaged only when motion in specific directions is required. The decoupled actuation system allows independent control of pitch and yaw motors, enabling the system to minimize active mass during operation by keeping non-required actuators disengaged, thereby reducing effective weight during movement while maintaining enhanced range of motion capability.
Solution Approach 2:
Weight reduction is achieved by optimizing the mass distribution and material properties of specific components. The parallelogram linkage members and actuator housings utilize high-strength, low-density materials, and the motor mounting structure is locally reinforced only where structural integrity is critical, allowing weight reduction in non-critical areas while maintaining the enhanced rotational capability about the first axis.
3Adaptability or versatility
If an offset parallelogram linkage configuration is used, then the range of motion along pitch axis is improved, but the device complexity increases
Solution Approach 1:
The parallelogram linkage is configured with an asymmetric offset where the linkage members are positioned at different distances from the rotation axes. This asymmetric arrangement creates favorable mechanical leverage ratios that expand the effective range of motion along the pitch axis. The offset configuration is carefully designed to maintain geometric constraints that simplify the kinematic relationships, preventing excessive complexity while achieving enhanced motion capability.
Solution Approach 2:
The linkage geometry parameters, including the offset distances and member lengths, are optimized to achieve the desired range of motion while maintaining manageable complexity. By carefully selecting these parameters, the system achieves improved pitch axis motion through mathematical optimization of the linkage configuration, balancing the trade-off between motion range and structural complexity.
Data Source
AI summary
Medical, surgical, and/or robotic devices and systems often including offset remote center parallelogram manipulator linkage assemblies which constrains a position of a surgical instrument during minimally invasive robotic surgery are disclosed. The improved remote center manipulator linkage assembly advantageously enhances the range of instrument motion while at the same time reduces the overall complexity, size, and physical weight of the robotic surgical system.