Extendable Prismatic Links for Compact Surgical Robotic Arms
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Solution Overview
Problem
Existing robotic arms for surgical applications are hardware-constrained, requiring long, fixed-length links that occupy large spatial volumes, inhibit access, and necessitate bulky motors, are expensive, and cannot be stowed under the surgical table.
Innovation Solution
A software-controlled robotic arm with extendable prismatic links and independently actuated joints, allowing for variable lengths and orientations, which can be compacted for stowage and expanded for operation, maintaining a remote center of motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hardware-constrained robotic arms with fixed-length links are used, then a predetermined motion and remote center of motion are achieved, but large spatial volumes are occupied and access to the patient is inhibited
Solution Approach 1:
The patent applies dynamics by transitioning from hardware-constrained fixed-length links to software-controlled variable-length links. The robotic arm uses actively driven joints with motors that can adjust link lengths in real-time, allowing the system to dynamically change its configuration. This enables the arm to maintain the remote center of motion constraint through software control while occupying smaller spatial volumes when not in use.
2Adaptability or versatility
If long, fixed-length links are used, then desired range of motion is achieved, but inertial loads increase requiring bulky and expensive motors
Solution Approach 1:
The system uses dynamically adjustable link lengths to optimize performance. When full range of motion is needed, the links extend to provide the necessary reach. When repositioning or in standby mode, the links retract to minimize inertial loads. This dynamic adjustment allows the use of smaller, less expensive motors while maintaining the required range of motion capability.
Solution Approach 2:
The patent changes the parameter of link length from fixed to variable. By actively controlling the length of each link through motor-driven joints, the system can adjust its physical parameters in real-time. This allows optimization of inertial properties during different phases of operation, reducing the power requirements and enabling the use of more compact motors.
3Adaptability or versatility
If long, fixed-length links are used, then range of motion is maintained, but the robotic arm cannot be stowed under the surgical table
Solution Approach 1:
The robotic arm employs dynamically variable link lengths that can be adjusted between extended and retracted states. During surgical operations, the links extend to provide the necessary range of motion for tool manipulation. When not in use, the links retract to allow the entire arm to be stowed underneath the surgical table, optimizing operating room space utilization.
4Reliability
If hardware-constrained linkages are used, then predetermined motion is imposed, but large spatial envelopes are swept during surgery
Solution Approach 1:
The system replaces hardware constraints with software control to dynamically adjust link lengths. This allows the robotic arm to sweep out smaller spatial volumes during repositioning and stowage operations while maintaining the ability to impose predetermined motions during surgical tasks through coordinated control of the actively driven joints.
Data Source
AI summary
Robotic arms and surgical robotic systems incorporating such arms are described. A robotic arm includes a roll joint connected to a prismatic link by a pitch joint and a tool drive connected to the prismatic link by another pitch joint. The prismatic link includes several prismatic sublinks that are connected by a prismatic joint. A surgical tool supported by the tool drive can insert into a patient along an insertion axis through a remote center of motion of the robotic arm. Movement of the robotic arm can be controlled to telescopically move the prismatic sublinks relative to each other by the prismatic joint while maintaining the remote center of motion fixed. Other embodiments are also described and claimed.