Direct-Drive Vitreoretinal Robot With Dual-Tripod Stabilization
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Solution Overview
Problem
Current robotic surgical systems for ophthalmic microsurgery, particularly vitreoretinal surgery, face challenges such as limited dexterity, accuracy, and inability to handle patient eye and head movements, leading to complications like retinal breaks and visual impairment.
Innovation Solution
A direct drive robotic system with a dual tripod structure and parallel kinematic links, mounted to a patient's head, providing 6-7 degrees of freedom and force feedback, along with a counterbalancing mechanism to stabilize the system against patient movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current robotic systems with 4 degrees-of-freedom are used, then device complexity is reduced, but the system cannot detect and correct for sudden head and eye movements or rotate the eye to visualize around corneal or lens opacities
Solution Approach 1:
The robotic system transitions from a static 4-DOF configuration to a dynamic 6-DOF parallel kinematic structure that can adapt in real-time to patient head and eye movements. The parallel architecture with multiple actuated links enables dynamic reconfiguration of the surgical tool's position and orientation, allowing the system to track and compensate for involuntary movements while maintaining surgical precision.
Solution Approach 2:
The system adds two additional degrees of freedom to the traditional 4-DOF robotic configuration, transitioning from planar to spatial manipulation. This dimensional expansion enables the surgical tool to access and visualize the peripheral retina, rotate around corneal or lens opacities, and respond to three-dimensional head and eye movements of the patient.
2Ease of manufacture
If serial articulated robotic arms are used, then ease of manufacture is improved, but cumulative joint error, kinematic singularities, decreased precision, and decreased speed occur
Solution Approach 1:
The system employs a parallel kinematic architecture that replicates the functional capabilities of serial robotic arms while eliminating their inherent disadvantages. By using multiple independent actuated links that converge at the surgical tool, the system achieves high precision without cumulative joint errors, as each link is directly actuated and controlled independently rather than through a chain of serial joints.
Solution Approach 2:
The patent replaces the traditional serial mechanical linkage system with a parallel kinematic mechanism directly actuated by voice coil motors. This substitution eliminates mechanical joints and their associated backlash, friction, and cumulative errors, achieving micron-scale positioning accuracy through direct electromagnetic actuation of the surgical tool.
3Reliability
If digital eye tracking is used to minimize risk from patient movement, then reliability is improved, but sudden head and eye movements caused by sleep apnea or startled response cannot be detected and corrected
Solution Approach 1:
The robotic system is pre-configured with a parallel kinematic structure and multiple sensors that enable immediate detection and response to patient movements. The system maintains readiness to adjust the surgical tool's position and orientation instantaneously, eliminating the delay associated with traditional eye tracking systems that process and react to movements sequentially rather than in parallel.
Solution Approach 2:
The system implements real-time feedback through multiple sensors including eye trackers, head position sensors, and force sensors that continuously monitor patient movements and surgical tool position. This multi-channel feedback system provides redundant information streams that enable the control system to detect and correct sudden head and eye movements immediately, enhancing both reliability and response speed.
4Device complexity
If current robotic systems only provide scaling without force control or force feedback, then device complexity is reduced, but sensory and motor limitations of surgeons are not effectively addressed
Solution Approach 1:
The robotic system incorporates force feedback mechanisms that provide counterbalancing forces to the surgeon's inputs, compensating for the surgeon's sensory and motor limitations. The force sensors detect tissue forces and provide proportional feedback through the master controller, creating a counterbalancing effect that enhances the surgeon's perception of tissue properties and enables more precise force application during micron-scale maneuvers.
Data Source
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AI summary
The present disclosure relates to high dexterity robotic manipulation systems for ophthalmic microsurgical procedures. In certain embodiments, a robotic surgical system includes a master apparatus controllably coupled to a slave apparatus. The slave apparatus mounts to a patient's head and includes a dual tripod structure having two pluralities of linear actuator links pivotally supporting a surgical tool. The motions of the actuator links are controlled by direct drive actuators to provide at least 6-DOF for the surgical tool. A passive articulating arm having a SCARA mechanism and four-bar parallelogram mechanism attaches to the slave apparatus and counterbalances the weight thereof when mounted on a patient. The surgical system also includes sensors communicatively coupled to the slave apparatus and master apparatus to enable force feedback and force control. Accordingly, the robotic surgical system enhances the dexterity of an operator and enables performance of medical procedures more easily than by hand.