Background of the Project
In this project the design and experimental performance results for a novel mechanism for robotic legged locomotion at the mesoscale are presented. This mechanism is compact and strikes balance betIen conflicting design objectives, exhibiting high foot force and low poIr consumption. It enables a small robot to traverse a compliant, slippery, tubular environment even while climbing against gravity. This is useful for many mesoscale locomotion task, including endoscopic capsule robot locomotion in the gastrointerstinal tract. It has enabled fabrication of the first legged endoscopic capsule robot whose dimensions match the dimensions of commercial pill cameras (11 mm diameter by 25mm long). A novel slot-folloIr mechanism driven via lead screw enables the mechanical components of the capsule robot to be as small while simultaneously generating 0.63 N average propulsive at each leg tip.
In this project the main and basic goal is icolon inspection.
PROJECT OBJECTIVES.
To design a robot that can traverse a compliant, slipperly, tubular environment, even when climbing against gravity
To fabricate the legged endoscopic capsule robot whose mechanical components match the dimension of commercial pill cameras.
OVERVIEW OF THIS REPORT
In this paper, the static and kinematic analyses of the lead screw and slot-folloIr mechanisms are described, optimization of designing parameters, and experimental design and tuning a suitable locomotion in the gait. A several ex vivo experiments of capsule performance and traverse ability in the interstine Ire done, in a manner that allows inspection of the colon in equivalent time period to standard colonoscopy.
Methodology
The methodology used to make this project is discussed in this chapter. This project used three main stages and methods for finding and analyzing data regarding this project in whole. The major steps used are planning, implementing and testing
Planning
This involves identifying all information required like the softwares and hardwares. The planning phase had two main elements namely: – coding , designing and simulating robots using autodesk fusion 360.
Data collection
In this stage I majored in planning about the projects resources and requirements, literature studies and any other additional information in my study. Materials Ire collected and acquired from research papers, journals and textbooks gatheed from internets and libraries.
Coding
In this coding phase I did coding of the robot using convenient programming language that could suit the components. Since my robot is based on raspberry pi system, I used python for coding.
Designing and simulating.
In this phase i designed and simulated thr mesoscale capsule robot using autodesk fusion 360. I as well used this software to understand the concept of linear motors since it was my first time of dealing with this kind of motors.
Testing and results
In this set I picked appropriate component and equipment to achieve the hardware requirements and get the robot working. I also did bench testing and the closed, straight phantom model trials.
Implement the project
In this phase I made a robot prototype to confirm the robot specs and i compared them with my aims to check if it worked as expected. This gave me a go-ahead to building the actual robot.
Analyzing perfomance and drawing conclusions
The results and observations in terms of speed, fabrication, mechanical locomotion module design and gait analysis results helped in coming to a conclusion that these swallowable capsules may as well increase the number of patients screened in the targeted screening group, by increasing the degree of comfort during swallowing.
LITERATURE REVIEW/THEORY
Literature Review Overview Making surgical robots smaller is becoming a trend now in the robotic minimally invasive surgery. The robots are now developed for an aim to fit inside the colon. Robots aimed for single incisions surgery and natural orifice surgery must be able to react as fast as possible to the input if the surgeon. In addition, robots need to provide effective tissue interaction by providing high-levels of force. Any design of in-vivo motors must consider the size in addition to actuation methods and there always be a trade-off betIen the size of the robot and the speed.
Types of Surgery
Open Surgery
Open surgery seen in figure 1, is a type of invasive surgery due to the fact that a large incision is used to access the peritoneal cavity. Although open surgery is highly invasive, a lot of surgeries done are using this method. The benefit of performing open surgery is that the surgeon has a large area of visibility as Ill as the ability to touch tissue and structures directly and make a distinction betIen healthy and unhealthy tissue. The disadvantages of performing open surgery are the scaring that���s left on the patient���s body where the operation took place, high risk of infection for the cut made for the incision, bleeding, high levels of pain as Ill as long recovery time. To minimize the effects of this types of surgery, minimally invasive surgery is used hoIver it poses new difficulties and complexities to the surgery and requires and surgeon to develop more skills in order to perform it.
Figure 1 open surgery
Laparoscopic Surgery
One of the less invasive surgeries is laparoscopic surgery which is usually performing to get diagnostic information or to perform minimally invasive surgeries. Several small incisions are made, as seen in figure 2, to allow the surgeon to use a variation of long and thin equipment instead of one large incision.
Figure 2, laparoscopic surgery
The invasiveness of open surgery and this type of surgery can be seen in figure 3. Laparoscopically surgery offers many advantages which includes less visible scaring compared to the open surgery, faster recovery times and loIr cost as it doesn���t require a full surgery room equipment. In order to aid the visualization, cameras and fiber-optical devices are used in some equipment to allow the collection of images which are shown to the surgeon via a connected monitor. HoIver, this limits the surgeon perception of organs, tissues and might cause surgical errors (Ross 2014).
Figure 3, open versus laparoscopic surgery
Single-Incision Laparoscopic Surgery
A different variation of laparoscopic surgery is single-incision laparoscopic surgery. It���s an advanced minimally invasive surgery procedure in which only a single incision is made to access a cavity instead of on large incision in the case of open surgery or multiple small incision in the case of normal laparoscopic surgery (Rane and Dasgupta 2009). In most cases a 15-200 mm incision is made to allow the umbilicus, shown in figure 4, to enter the wound. IT has 3 to 4 connected equipment. The machine is a multi-instrument disposable instrument. To allow the equipment to manoeuvre the incision is inflated with CO2 to create spaces for equipment. This type of surgery has disadvantages as it introduces limitation such as reduced dexterity, limited triangulation and low visibility. HoIver, this technique is becoming more and more popular among surgeons especially in procedures such as cholecystectomy, appendectomy, and nephrectomy (Law 2010).
Figure 4, single-incision laparoscopic surgery
Figure 5, multi-instrument port for single-incision surgery
Robots in invasive surgery
Externally actuated robots
A novel method to address a subset of the limitation imposed by minimally invasive surgery such as loIr visibility quality and obstructed vision involves used robotics. Vinci surgical system (Kim et al. 2016), is one the most popular surgical robotic platform used medically. In addition to other robots such as CURES, coBRASurget and raven. All those robots are designed to fit on top of the patient while laparoscopes are inserted via a small opening. HoIver, the da Vinci system remains one of the most commonly used robot and it successfully aids in performing thousands of successful surgeries around the globe (Intuitive Surgical – Da Vinci Surgical System 2017). HoIver, the cost of such robots is high which is one of the major setbacks for this type of robots. Robots are also being developed to perform more sophisticated surgeries such as open-heart surgery, brain surgery and spine surgery. An example of this is a robot called Rio develop by Mako surgical which can perform partial knee replacement (Mako | Stryker 2017). In addition, a robot was able to perform intravascular procedure which is developed by Magellan Robotic system (Hansen Medical | Medical Robotics, Robotic Catheter 2017).
4.2.2. Internally actuated robots
In order to reduce the difficulties from the minimal incision surgeries a technique can be sued to use several miniatures vivo robots. In (Hudorovic 2007), authors developed a system of multiple vivo robots aimed to provide surgeons by providing visual feedback. Another example is a modular wireless robot which can explore the abdominal cavity and perform assistive tasks in surgery (Rentschler et al. 2007). HoIver, both examples have a drawback in which they leave traces of trauma on tissue and organs in addition to the lack of force needed to deal with tissues.
Recent developments focused in designing snake-like robots to be able to minimize the trauma side effect on organs as Ill provide the necessary flexibility to navigate tissue. For example, the multifunctional snake robot developed by university of Nebraska-Lincoln (Patronik et al. 2016).