Micro-motion controller

Micro-motions in surgical applications are small motions in the range of a few millimeters and are common in ophthalmic surgery, neurosurgery, and other surgeries which require precise manipulation over short distances. Robotic surgery is replacing traditional open surgery at a rapid pace due to the obvious health benefits, however, most of the robotic surgical tools use robotic motion controllers that are designed to work over a large portion of the human body, thus involving motion of the entire human arm at shoulder joint. This requirement to move a large inertial mass results in undesirable, unwanted, and imprecise motion. This senior design project has created a 2-axis micro-motion “capable” platform, where the device studies the most common linear, 2-D surgical micro-motion of pinched human fingers in a damped and un-damped state. Through a system of printed and modeled parts in combination with motors and encoders a microsurgical controller was developed which can provide location-based output on a screen. Mechanical damping was introduced to research potential stability of micro-motion in any surgeon’s otherwise unsteady hand. The device is to also serve as a starter set for future biomedical device research projects in Santa Clara University’s bioengineering department. Further developments in the microsurgical controller such as further scaling, addition of a third axis, haptic feedback through the microcontroller, and component encasing to allow productization for use on an industrial robotic surgical device for clinical applications

Multi-objective optimization of end-to-end sutured anastomosis for robot-assisted surgery

Background Due to differences in surgical operations between free-hand and robot-assisted vessel anastomosis, there exist new challenges in applying the manipulation criteria of free-hand surgery to robot-assisted surgery in order to guarantee successful completion of the surgical procedure. Methods A mathematical model is established to optimize the process variables in vessel anastomosis. The distance between entry point and cross-section, suture tension and the number of individual sutures are selected as design variables. The allowable range of suture tension and the difference between longitudinal stresses of vessel tissue on transverse sections are used as the objective functions. Simulation experiments are carried out to obtain the allowable range of suture tension and tissue stress distribution, based on numerical analysis. Results For a vessel in anastomosis with 4 mm diameter, a larger distance between the entry point and the cross-section and/or more sutures can result in less tissue deformation and a tighter joint between the two vessel ends. The allowable range of suture tension is a function of the number of individual sutures and increases with the decrease of the distance between entry point and cross-section. The optimal designs providing the suture configuration of distance between entry point and cross-section and the number of individual sutures are presented in the case that the performance of robot-assisted anastomosis can be guaranteed without strong control of suture tension. Conclusions The work provides meaningful results for the optimal design of the suturing procedure in robot-assisted vascular anastomosis when the robotic system does not allow tactile feedback. Copyright © 2010 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78069/1/347_ftp.pd

Scalability study for robotic hand platform

The goal of this thesis project was to determine the lower limit of scale for the RIT robotic grasping hand. This was accomplished using a combination of computer simulation and experimental studies. A force analysis was conducted to determine the size of air muscles required to achieve appropriate contact forces at a smaller scale. Input variables, such as the actuation force and tendon return force, were determined experimentally. A dynamic computer model of the hand system was then created using Recurdyn. This was used to predict the contact (grasping) force of the fingers at full-scale, half-scale, and quarter-scale. Correlation between the computer model and physical testing was achieved for both a life-size and half-scale finger assembly. To further demonstrate the scalability of the hand design, both half and quarter-scale robotic hand rapid prototype assemblies were built using 3D printing techniques. This thesis work identified the point where further miniaturization would require a change in the manufacturing process to micro-fabrication. Several techniques were compared as potential methods for making a production intent quarter-scale robotic hand. Investment casting, Swiss machining, and Selective Laser Sintering were the manufacturing techniques considered. A quarter-scale robotic hand tested the limits of each technology. Below this scale, micro-machining would be required. The break point for the current actuation method, air muscles, was also explored. Below the quarter-scale, an alternative actuation method would also be required. Electroactive Polymers were discussed as an option for the micro-scale. In summary, a dynamic model of the RIT robotic grasping hand was created and validated as scalable at full and half-scales. The model was then used to predict finger contact forces at the quarter-scale. The quarter-scale was identified as the break point in terms of the current RIT robotic grasping hand based on both manufacturing and actuation. A novel, prototype quarter-scale robotic hand assembly was successfully built by an additive manufacturing process, a high resolution 3D printer. However, further miniaturization would require alternate manufacturing techniques and actuation mechanisms

Automatic Microassembly System for tissue engineering- Assisted with top-view and force control

Master'sMASTER OF ENGINEERIN