Surgical Robot Joint Structure for Precise RCM Instrument Alignment
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Solution Overview
Problem
Existing surgical robots face challenges in maintaining precise control over the movement of surgical instruments to avoid non-surgical damage to the patient's incision during minimally invasive procedures, particularly due to the complexity of aligning the remote center of motion (RCM) with the instrument's longitudinal axis.
Innovation Solution
A robotic manipulator design featuring a base, first, second, and third links, with a transmission mechanism that includes pulley assemblies and flexible transmission assemblies, allowing for precise alignment of the surgical instrument's motion through a remote center of motion, ensuring the instrument's longitudinal axis consistently passes through this point, using adjustable flanged shafts and tensioning structures to maintain alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a robotic manipulator uses a complex transmission mechanism with multiple pulley assemblies and flexible transmission assemblies to achieve precise RCM alignment, then the manufacturing precision and movement control are improved, but the device complexity increases
Solution Approach 1:
The transmission mechanism is divided into multiple independent pulley assemblies (first pulley assembly at first joint, second pulley assembly at second joint) that can be independently adjusted. Each pulley assembly handles a specific degree of freedom, allowing modular adjustment and simplifying the overall system design while maintaining precise RCM alignment control
Solution Approach 2:
The flanged shafts are designed with rotational adjustability relative to their respective links. This dynamic adjustment capability allows the system to adapt the transmission paths in real-time to maintain precise RCM alignment during multi-DOF movements, resolving the contradiction between precision and complexity through adaptive geometry
2Reliability
If the robotic manipulator employs adjustable flanged shafts and tensioning structures to maintain precise alignment, then the reliability of RCM maintenance is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The tensioning structures are designed to automatically maintain appropriate tension in the flexible transmission assemblies during operation. This self-adjusting mechanism ensures reliable RCM alignment maintenance without requiring complex external tensioning systems or frequent manual adjustments, improving reliability while keeping manufacturing feasible
Solution Approach 2:
The flanged shafts are pre-configured with rotational adjustment capabilities that allow alignment to be set during assembly. This preliminary alignment setup ensures reliable RCM maintenance from the start, reducing the need for complex post-assembly calibration procedures
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 design ensures high-precision movement of surgical instruments, minimizing the risk of non-surgical damage by maintaining the instrument's axis through the RCM, enhancing the safety and efficacy of minimally invasive surgeries.
Implementation Method 1
Each of the pulley assemblies includes: a flanged shaft and a pulley
Implementation Method 2
flexible transmission assemblies connecting an actuator, the pulley assemblies, and the instrument holder
Data Source
AI summary
A robotic manipulator, a joint structure, and a surgical robot. The robotic manipulator comprises a base, a first link, a second link, a third link, an instrument holder, and a transmission mechanism. The first link is rotatable about a first axis relative to the base. The instrument holder can move a surgical instrument to translate along a second axis. The second axis is fixed relative to the instrument holder and intersects with the first axis at a remote center point. The transmission mechanism is used for driving the instrument holder to rotate about a third axis. The third axis passes through the remote center point.