Excerpt
Contents
ABSTRACT
INTRODUCTION
LITERATURE REVIEW
2.1 TELE-ROBOTIC SURGERY
2.2 HAPTICS IN SURGICAL INSTRUMENTS
2.2.1 FORCE FEEDBACK DEVICES
2.2.2 TACTILE DEVICES
2.2.3 SOFIE (SURGICAL ROBOT)
2.3 MODULES OF SURGICAL SYSTEM
2.3.1 MASTER-SLAVE ROBOTIC SURGERY
2.3.3 MASTER UNIT
2.3.4 MECHANICAL WORK
2.3.5 ELECTRICAL WORK
FUNCTIONALITY AND DESIGN
3.1 MECHANICAL STRUCTURE & EQUATION DERIVATION
3.1.1 PRO E DESIGN
3.1.2 ROBOTIC ARM COMPONENTS DESCRIPTION
3.1.3 FORWARD AND BACKWARD MOTION (‘R’)
3.1.4 VERTICAL MOTION (Z-AXIS)
3.1.5 MOVEMENT IN XY PLANE
3.2 ELECTRICAL COMPONENTS
3.2.1 MAXON DC MOTOR WITH ENCODER & GEARBOX
3.2.2 FORCE SENSOR
3.2.3 TRANSDUCER
3.2.5 ROBOTIC ARM GRIPPER
3.2.6 H-BRIDGE DESIGN:
3.3 SOFTWARE COMPONENTS
3.3.1 PROJECT TOP MODEL PSOC CREATOR
3.3.2 MICROSOFT VISUAL C#
3.3.3 .NET FRAMEWORK PLATFORM ARCHITECTURE
3.3.4 PROJECT REQUIREMENTS FOR GUI
3.3.5 COMMUNICATION METHODOLOGY
3.3.6 COMMUNICATION PROTOCOL
3.3.7 PROJECT INTERFACE
3.3.8 VISUAL STUDIO C# CODE
3.3.9 PSOC CODE EXPLANATION
IMPLEMENTATION AND RESULT DISCUSSION
4.1 METHODS AND ALGORITHM USED FOR FEEDBACK
4.1.1 CURRENT SENSING
4.1.2 POSITION ESTIMATION (DIGITAL ENCODERS)
4.1.3 OBJECT DETECTION USING FSR AT GRIPPER
4.2 EXPERIMENT RESULTS AND THEIR ANALYSIS
4.2.1 HARD OBJECTS (ANIMAL BONE):
4.2.2 SOFT OBJECTS:
4.2.3 SEMI HARD OBJECTS (ANIMAL FLESH):
FUTURE RECOMMENDATIONS AND CONCLUSION
REFERENCES
FIGURE 1: GENERAL SURGICAL PROCEDURE
FIGURE 2: MINIMALLY INVASIVE SURGERY
FIGURE 3: MASTER UNIT OF DA VINCI
FIGURE 4: SLAVE UNIT OF DA VINCI ROBOT
FIGURE 5: SIMQUEST’S BURR HOLE DRILLING SIMULATION HARDWARE
FIGURE 6: COMMERCIAL FORCE FEEDBACK HARDWARE MANUFACTURES AND DEVICES
FIGURE 7: SLAVE AND MASTER UNIT OF SOFIE ROBOT
FIGURE 8: MASTER-SLAVE SETUP
FIGURE 9: FLEXI FORCE SENSOR
FIGURE 10: TRANSIENT RESPONSE OF A FORCE SENSOR
FIGURE 11: TEXAN FLEXI FORCE SENSOR TRANSFER CHARACTERISTICS
FIGURE 12: STRUCTURE TOP VIEW
FIGURE 13: STRUCTURE SIDE VIEW
FIGURE 14: MODELING DESIGN
FIGURE 15:RESOLVED COMPONENTS FOR FORWARD AND BACKWARD MOTION
FIGURE 16: RESOLVED COMPONENTS FOR VERTICLE MOTION
FIGURE 17: RESOLVED COMPONENTS FOR MOVEMENT IN Y PLANE
FIGURE 18: RESOLVED COMPONENTS FOR MOVEMENT IN X PLANE
FIGURE 19: ACTUATORS
FIGURE 20: FSR
FIGURE 21: PSOC KIT
FIGURE 22: GRIPPER FRONT AND SIDE VIEW
FIGURE 23: H-BRIDGE
FIGURE 24: TOP MODULE FOR DRIVING 2 MOTORS
FIGURE 25: .NET FRAMEWORK ARCHITECTURE
FIGURE 26: TOOLBOX OF VISUAL STUDIO
FIGURE 27: GUI
FIGURE 28: VOLTAGE ACROSS CURRENT SENSING RESISTOR FLOWING THROUGH SERVO (A) WHEN LESS CURRENT IS FLOWING (B) WHEN MORE CURRENT IS FLOWING
FIGURE 29: ANALOG TO DIGITAL CONVERTOR AND PWM BLOCKS IN PROGRAMMABLE SYSTEM ON CHIP
FIGURE 30: PSOC PWM CONFIGURING MODULE
FIGURE 31: CURVE DIVISION ALONG Y-AXIS (FSR VALUES) INTO DIFFERENT PARTS FOR OBJECT DETECTION
FIGURE 32: CURVE DIVISION ALONG X-AXIS INTO DIFFERENT PARTS FOR OBJECT DETECTION
FIGURE 33: COLOR INTENSITY BLOCK AND SIZE TRACK BAR
FIGURE 34: GRAPHS OF FSR AND RESULT AT GUI USING ANIMAL BONE
FIGURE 35: GRAPHS OF FSR AND RESULT AT GUI USING HARD PLASTIC
FIGURE 36: GRAPHS OF FSR AND RESULT AT GUI USING SOFT FOAM
FIGURE 37: GRAPHS OF FSR AND RESULT AT GUI USING ANIMAL FLESH
FIGURE 38: GRAPHS OF FSR AND RESULT AT GUI USING SQUEEZABLE RUBBER
ABSTRACT
Haptic Feedback systems are used to sense the vibrations, touch and force in many real world problems for example gaming, virtual reality, mobiles, automotive industry and robotic surgery. Our work involves the design and development of a robotic arm at slave end which includes force and current sensors that allows the operator to get force feedback at the master end. Three methods of feedback are generally used i.e. Force Sensitive Resistors for object detection, Current Sensing for force feedback and Position estimation to replicate motion. The three mentioned methods are analyzed using graphs developed on the PC.
Graphs are obtained by experiments on the gripper by using different objects. Master-Slave topology is used to attain some benefits over conventional control systems in term of ergonomics, accuracy and timing etc. There is an interactive GUI at master end to show us forces, size and motions at each joint of the slave unit. Along with the interactive GUI at master side, yaw and pitch motion of slave is also replicated at master end using master controller.
Chapter 1
INTRODUCTION
Today’s era is the era of robots and machines. People want machines to operate their task efficiently. With all other domains of Robotics, Robotics Surgery also gains popularity in last few years. Many surgical robots have been developed in which da Vinci is a famous one. In Robotic Surgery different robotics system used to aid surgical procedures. Robot-assisted surgery is a minimally invasive surgical technique in which a slave robot is utilized to manipulate surgical tools. By manipulating a master controller, the surgeon dictates the robot’s movements and indirectly the surgical tool’s movements. Robot-assisted surgery offers an alternative to conventional laparoscopic procedures where the surgeon directly controls surgical instruments.
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Figure 1: General Surgical Procedure
Robot-assisted surgery has greatly influenced modern surgery by decreasing invasiveness in body and by minimizing patient trauma, recovery time, and cost. Visual inspection, palpation, and characterization of the trauma site and the surrounding area play a crucial role in diagnosis and treatment as experienced surgeons have relied on these faculties to make intraoperative decisions and improve diagnostic capability for which there is need of haptic feedback. One of the most significant shortcomings of robotic-assisted surgery is the absence of haptic feedback, or the surgeon’s sensation of tool-interaction forces. Haptic feedback is inherently present in both conventional laparoscopic and traditional open surgery as the surgeon directly manipulates the surgical tools and forces are more easily transmitted through the physical connection. To assist surgeon efficiently there is need to integrate haptic with these surgical robotics systems. Haptic signals can be either kinesthetic, vector forces applied at points or on Joints, or tactile, textures and distribution of forces.
Haptic is an important component of surgery and can enable a surgeon to differentiate tissue, perceive the amount of force applied to tissue, and generally determine the contour and compliance of tissue Haptic feedback has the potential to provide superior performance and reliability to RMIS systems. There are two major type of haptic feedback.
1-Force feedback
2-Tactile Feedback
Force feedback is very popular these days in RMIS. But many researchers agree that the addition of tactile sensation under proper conditions would be a valuable feature in master-slave robot-assisted surgery. Difficult part in tactile feedback is that it typically requires an array of sensors whereas kinesthetic or forced feedback may require the careful placement of very few sensors. Basic purpose of haptic feedback is to realize surgeon a tool-tissue interaction forces. But there is no such modules developed which are cost effective and commercially liable and provide all feature to RMIS discussed earlier. The goal of our design project is to design a device to provide kinesthetic haptic feedback during robot-assisted surgery. Ultimately, the team seeks to develop a force sensing module which is low cost and commercially acceptable. And that design should fulfill maximum shortcomings which surgeons face during RMIS.
Chapter 2
LITERATURE REVIEW
2.1 Tele-Robotic Surgery
The surgery done with the help of a robot at a subject placed at some distance from the operator (surgeon). Robot is well equipped with surgical procedures. This kind of procedure is usually used in MIS (minimal invasive surgery). This kind of surgery is used so that the video feed and the operating instrument could be operated at the same time by the surgeon. Due to the usage of computer operated instrument the accuracy of the surgeon is increased. Ergonomics are improved. Healing time and smaller incisions are made. Surgeon hand tremors can be filtered which is one of the major advances. Recently a lot of advanced has been made in this field.
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Figure 2: Minimally Invasive Surgery
The first robotic instrument used for surgery occurred in 1985[1]. PUMA 560 robotic surgical Arm was used. This robotic instrument had greater precision in MIS due to flexible fiber optics. In 1990 the AESOP system designed by Computer Motion was the first surgical system approved by the Food and Drug Administration (FDA) for its endoscopic surgical method. In 2000 da Vinci surgical system was the first robotic system approved by FDA. Da Vinci allowed high resolution feed back to the operator. It had one centimeter surgical arm which gave an advantage compared to Puma 560. . This advancement led towards less contact between exposed interior tissue and the surgical system, which greatly reduces the risk of infection in body. The surgeon movement is replicated with the help of “Endo-wrist” feature thus improving accuracy and precision in small operating places.
Da Vinci is the most advance and sophisticated machine for Tele-Robotic surgery. Master and slave topology has been used in da Vinci. Master with the help of a controller controls the slave.
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Figure 3: Master Unit of da Vinci
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Figure 4: Slave unit of da Vinci robot
2.2 Haptics in Surgical Instruments
Haptics means “sense of touch”. Haptics in Tele-Surgical Robot plays a very important role especially in MIS, which leads us to next step of Tele-Robotics surgery. It gives us real sense of touch tactile feedback at slave part of surgical robot. It reduces the contact forces, energy consumption and task completion time and number of errors from surgeon side. Study shows that task completion time by 30% and error rate reduction by 60%. The sense of touch would be added to virtual environment was predicted by Sutherland in 1965. He predicted that the user would be able to feel the virtual environment.
2.2.1 Force feedback devices
Means the force that the slave arm feels is fed to the master end controller. Different types of actuators are used in Force feedback devices. Haptic feedback requires faster rate of “haptic image” update. This requires a lot of computational power.
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Figure 5: Simquest’s burr hole drilling simulation hardware
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Figure 6: Commercial Force Feedback Hardware Manufactures and Devices
2.2.2 Tactile devices
Tactile information is delivered by compressing, stretching or vibrating, and varying of the heat at the skin surface of human body. To copy and then to manipulate the human touch receptors is a hard task so not so much work has been done as compared to force feedback. It’s extremely costly and also size limitation is a problem.
2.2.3 Sofie (surgical robot)
Surgeon’s Operating Force-feedback Interface Eindhoven (Sofie)[5] is a surgical robot which incorporates Force Feedback. It’s the first robot to include force feedback. It is developed by dr. ir. Linda van den Bedem. It’s a master-slave topology design. The master controls the slave. Master is controlled by the operator. Master includes force feedback joystick and console which separates from slave. Slave has 3 independent manipulators which includes two surgical tools and a camera for visual feedback. It follows a pick and place robot functionality. You can feel exactly what force you applying using suture and pushing of tissue by using this machine. Small dimension is another advantage. Slave is mounted on the operating procedure. It is developed in Eindhoven University of Technology. It will take about 5 years for Sofie to be actually practical.
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Figure 7: Slave and Master Unit of Sofie Robot
2.3 Modules of Surgical System
2.3.1 Master-Slave robotic surgery
Master-Slave topology is used because the movement in master replicates to the slave and solves many problem encountered in conventional surgeries in the following ways i.e.
- Ergonomics
Surgeon feels less fatigue during operations. Study shows that 30% less time required by using surgical system.
- Manipulation
Precision at slave end can be increased by scaling down the motion at master end. Interaction between instrument and tissue can be reflected to master end using force feedback and tactile sensors at slave end.
- Unilateral control system
In Unilateral there is no force feedback from slave end but visually information is available to the operator and it is simple and less expensive to build.
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- Bilateral control system
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In bilateral scheme we also have a force feedback signal from slave end to master using sensors in actuator. It is more complex and expensive to build compared to unilateral topology.
- Functional Block Diagram
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