Surgical Robot Arm Structure With Gravity-Balanced Vertical Motion
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Solution Overview
Problem
Conventional robotic arms used in minimally invasive surgical robots are bulky, complex, and heavy due to nested rotary joints, which hinder precise motion control and increase weight, and often rely on manual operation to avoid motor failure risks, complicating vertical movement adjustments.
Innovation Solution
A robotic arm design featuring a vertical movement joint, a rotary joint, and a horizontal movement joint, with a gravity-balancing mechanism using a constant-force spring and pulley system to reduce weight and complexity, allowing for precise and efficient movement in three-dimensional space without increasing the weight of the surgical robot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a surgical robot system is designed to be highly integrated and automated, then surgical precision and automation level are improved, but system complexity and cost increase
Solution Approach 1:
The surgical robot system is divided into multiple independent modules including a control console, a robotic arm assembly, an imaging system, and a surgical tool module. Each module can be independently controlled and maintained, reducing overall system complexity while preserving surgical precision through coordinated operation of these segmented components.
Solution Approach 2:
The robotic arm assembly is designed with universal joints and interchangeable tool interfaces that allow a single base structure to perform multiple surgical functions. This multi-functionality reduces the need for multiple specialized devices, lowering system complexity while maintaining high precision across different surgical tasks.
2Reliability
If more safety mechanisms and sensors are added to the surgical robot, then patient safety is improved, but device complexity and response time may worsen
Solution Approach 1:
Safety sensors and monitoring systems are pre-positioned and pre-calibrated before surgical procedures begin. Emergency stop mechanisms are pre-activated and hardwired into the control system, ensuring that safety responses can be executed immediately without requiring complex real-time processing or decision-making, thus maintaining both high safety and fast response time.
3Stability of the object's composition
If the robotic arm structure is made more rigid and stable, then surgical operation stability is improved, but adaptability to different surgical scenarios decreases
Solution Approach 1:
The robotic arm employs dynamically adjustable stiffness through active control of joint actuators and flexible coupling mechanisms. During stable phases of surgery, the arm maintains rigid positioning for precision, while during transitions between different surgical tasks, the arm can become more compliant to adapt to new configurations, thus achieving both stability and adaptability.
Solution Approach 2:
The robotic system allows real-time modification of operational parameters such as arm stiffness, speed, and positioning precision based on the specific surgical scenario. This parameter adaptability enables the same rigid-stable robotic arm structure to perform optimally across diverse surgical procedures by adjusting its mechanical and control characteristics.
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 simplifies the structure, reduces weight, enhances motion control precision, and facilitates easier manipulation by eliminating unnecessary joint displacements and gravity balancing issues, ensuring compactness and reliability in surgical procedures.
Implementation Method 1
configured to balance the gravity of the vertical movement joint
Implementation Method 2
a gravity-balancing mechanism disposed within the connecting lever and comprising a constant-force spring
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A surgical robot and a robotic arm thereof are provided. The robotic arm includes: a vertical movement joint (5) configured to move vertically; a rotary joint (2, 4) sleeved over a rotational shaft (6, 7) and configured to rotate thereabout to drive the vertical movement joint (5) to rotate; and a horizontal movement joint (1) configured to drive the rotational shaft (6, 7) to move horizontally. Only one horizontal movement joint (1) is used in lieu of the conventional plurality of inter-nested rotary joints to enable horizontal movement of the robotic arm. This reduction in the number of the used joints simplifies the structure of the robotic arm, minimizes its dimensions and reduces its overall weight. In addition to the structural simplification, the motion control precision is also increased without irrelevant displacements, making simpler operation possible.