Ergonomic Laparoscopic Tool Handle Design

Development of a micro manipulator for minimally invasive neurosurgery

K. Harada , ... K. Takakura , in Human Friendly Mechatronics, 2001

Surgical robots are useful for minimally invasive surgery, since it enables precise manipulation of surgical instruments beyond human ability in a small operation space. In this approach, we are developing a micro manipulator for minimally invasive neurosurgery. The micro manipulator consists of two micro grasping manipulators, a rigid neuroendoscope, a suction tube, and a perfusion tube. This paper reports on the micro grasping manipulator. It has two D.O.F for bending and one D.O.F for grasping. This prototype is 3.1 mm in diameter and can bend 30 degrees in any direction. Stainless steel wire was used to actuate the manipulator.

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Robotic Surgery

Pinar Boyraz , ... Marko B. Popovic , in Biomechatronics, 2019

15.1.1 Introduction: Traditional Robotic Surgery

Surgical robots assist during surgical procedures. They have been used since the mid-1980s. Today, the majority of prostatectomies in the United States are robot-aided procedures as chances for successful operation are higher with robotic aid than without.

Robotic surgeries are typically minimally invasive. This feature has been around long before the introduction of robots. It is a broad concept that encompasses many common procedures, such as a laparoscopic cholecystectomy, or gall bladder excisions. The procedure refers to a method that avoids long cuts by operating on the body through small (usually 1 cm) entry incisions. Surgeons use long-handled instruments to operate on tissue within the body. Such operations are guided by viewing equipment called endoscopes. These are thin tubes with a camera attached to the end of it that allows the surgeon to view highly magnified real-time three-dimensional images of the operation site on a monitor.

The current benefits of robotic surgery include better accuracy, precision, dexterity, tremor corrections, scaled motion, and more recently haptic corrective feedback. These benefits result in more successful surgeries and smaller necessary incision cuts. Overall, the robotic systems have better accuracy and precision than unaided surgeons. Surgical robots are able to position the surgical tools closer to the "right spot" and deviate less from the "right trajectory." The robot's end-effectors can be much smaller and more dexterous than a human hand. They can record and filter out a surgeon's natural hand tremor and rescale movement to increase precision and reduce the chance for error. Lastly, the robot could restrain the surgeon's movement into undesired directions through haptic feedback.

Researchers are formulating new ways to address motion and tissue resistance. For example, the surgical robot could synchronically move with a beating heart such that their relative speed is close to zero. Another possible improvement is the ability for the robot to automatically adapt to the dynamical tissue resistance over time as the sensitivity scale of these processes goes beyond human capabilities.

Typically, robotic surgery can be classified as either (i) supervisory-controlled, (ii) tele-surgical, or (iii) shared-controlled.

The supervisory-controlled approach is the most automated of the three methods. The RoboDoc from Integrated Surgical Systems Inc. is an example of a supervisory-controlled system used in orthopedic surgeries. After the surgeon positions the RoboDoc's bone-milling tool at the correct position inside the patient, the robot automatically cuts the bone to just the right size for the orthopedic implant.

Prior to the surgical procedure, the surgeon needs to prepare the operation through the planning and registration phase. In the planning phase, images of the patient's body are used to determine the right surgical approach. Common imaging methods include computer tomography (CT) scans, magnetic resonance imaging (MRI) scans, ultrasonography, fluoroscopy, and X-ray scans. Next, in the registration phase, the surgeon must locate the points on the patient's body that correspond to the images created during the planning phase. These points are matched to a 3D model, which can be updated by images seen through cameras or other real-time imaging techniques during surgery. After the robot finds the best fit between the model and reality, the surgical procedure is performed.

The tele-surgical approach allows the surgical robot to be tele-operated, that is, operated from a distance by a human surgeon. In practice, the robot and the surgeon are only a couple of meters apart. Tele-operation is also possible across larger distances. However, problems such as time delays (i.e., tele-surgical latencies) and the available bandwidth (i.e., the amount of information that can be transferred per unit time) need to be considered.

The tele-surgical approach is used by the da Vinci Surgical System, which was invented by Philip S. Green and developed by Intuitive Surgical Inc. This system currently dominates the surgical robot market. Initially dubbed Mona (after Leonardo's Mona Lisa), the system was rechristened the da Vinci Surgical Robot in 1999; according to Mr. Green "…in honour of the man who had invented the first robot." Although da Vinci never invented or built a real robot (credit for that goes to Tesla), he made many drawings of various mechanisms.

The da Vinci System consists of three primary components: (1) a viewing and control console that is used by surgeon, (2) a vision cart that holds the endoscopes and provides visual feedback and (3) a surgical robot's manipulator arm unit that includes three or four arms, depending on the model. The instruments that are attached to the arms are highly specialized. Functions for them include clamping, cutting, suturing, tissue manipulation, cauterizing, etc.

It takes some time for surgeons to get accustomed to the da Vinci System. According to a study, even with initial training program, provided by the Intuitive Surgical, it takes about 12–18 operations before surgeons feel comfortable performing the procedure. Often, during this period, surgeons complain on lack of tactile force feedback or ability to "feel" the tissue.

The shared-controlled approach refers to the method by which the robot is not just motion tele-operated as it can decide to resist the surgeons' intended movement if it deems that it would not be beneficial. Typically, the work space is split into several segments and the system behaves differently based on different localization according to safe, close, boundary, or forbidden classification. For example, if surgeon moves a cutting tool in the direction of tissue that should not be damaged, the robot will apply the force haptic feedback that will grow stronger as the cutting tool comes closer to the fragile tissue. In other words, here, surgeon again "feels" the virtual representation of tissue that may have preprogrammed specifications different from the real tissue as well as somewhat different localization in space.

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Robin Heart surgical robot: Description and future challenges

Zbigniew Nawrat , in Control Systems Design of Bio-Robotics and Bio-mechatronics with Advanced Applications, 2020

5.4 Software ergonomics

A surgical robot is now more a mechatronic tool than an IT (information technology) tool. However, the challenges of appropriate decision-making flexibility and precision (especially in the absence of professional staff in the conditions of demographic problems) indicate that the direction of development toward autonomous (partly or fully) medical robots is the most up-to-date. The idea of spaceflight and establishing bases in distant objects from Earth and the need to secure medical service has also returned.

The principles of ergonomics should be applied when creating software—ensuring the effectiveness, efficiency, and satisfaction of the employee. These three properties make up the software utility. Let us mention a few principles (called heuristics) of software ergonomics: feedback (for each activity there should be a reaction or system information); availability (providing tools and information according to the user's needs); simple and natural dialogue; application of the user's language (language of symbols from the user's environment); reducing the load on short-term memory (no need to memorize a lot of information); confirmation of activities (information on the effect of activities); and elimination of errors. The software created as part of the Robin Heart project meets these principles.

The issues discussed are the key to building the proper telemanipulator control system and software. Man, the operator of a surgical robot, can be treated as an element of the control system (we take into account both the processing of information in the brain and its dependent motor coordination of precise control—motion control, position, speed, and strength—through the robot interfaces) connected by the system IT and operation of the robot electromechanical system with an executive tool. In terms of artificial organs—and so you can treat the robot (as a prosthesis, prolonging the surgeon's hand)—it is a hybrid organ (because it is necessary for proper operation to use cells, natural organs, simply human-operator) (Nawrat, 2011).

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Robotic interventions

Sang-Eun Song , in Handbook of Medical Image Computing and Computer Assisted Intervention, 2020

34.3 Master–slave system

Teleoperated surgical robots provide superior instrumentation and versatile motion through small incisions controlled by the physician. Typically, the physician manipulates an ergonomic master input device in a visualization environment (physician console) and these inputs are translated into motion by a 3D vision system (endoscope) and wristed laparoscopic surgical instruments. The major advantage over the traditional (hand operated) surgical method is that it can compensate for human hand tremors and can also minimize the hand motion for surgical tasks, thereby reducing procedure time.

da Vinci [14,15] is used in multiple fields of surgery such as head and neck, thoracic, colorectal, gynecology, and urology in the form of laparoscopic surgery. The robot is equipped with 3 or 4 robotic arms. Incisions will be made for each instrument. One of the arms will be equipped with a 3D endoscope that displays on the visual system. In order to reduce trauma, the arms move around a fixed pivot point. Different instruments are designed with a specific purpose. Recent advancements include a single port system shown in Fig. 34.2.

Monarch platform [16,17] by Auris is intended for diagnostic and therapeutic bronchoscopic procedures. The teleoperated endolumenal robot can navigate inside the body, image, and treat conditions without making incisions. Monarch Platform is a neither a haptic feedback nor monitoring tool, as the robot only transmits visual information to the physician. It is not autonomous. Monarch Platform uses a custom controller to allow the physician to directly control the endoscope as the physician navigates the lungs. Visual feedback is given from the endoscope as well as an image display for navigation. The robot is mounted on a stationary platform that controls the feed rate of the endoscope. The feed rate and navigation are all controlled by the physician at the visual platform in a master–slave relationship.

Virtual Incision's miniaturized robot [18] is used for gastrointestinal operations. The Virtual Incision robot is inserted into the abdominal cavity after an incision is made at the belly button. The two-arm manipulator robot, equipped with an HD camera, performs the operation within the abdomen. It is mounted onto the side of the operating table with an adjustable positioning arm. Virtual Incision provides neither haptic feedback nor monitoring. Data is received through a monitor system for arm positioning. Video footage shows physicians controlling the robot with two Geomagic Touch devices and a custom master device. The slave device is a telemanipulator using a wireless connection between the master–slave system. Video is streamed from the HD camera for an endoscope image-based navigation.

Revo-I [19,20] is a laparoscopic surgical robot. Revo-I has been marketed in South Korea to be more cost effective than the da Vinci of Intuitive Surgical. Like da Vinci, Revo-I is a 4-arm robotic platform with one arm equipped with a 3D camera. Different end effector attachments allow customization of the operating procedure. It is currently designed with tactile feedback, which results in decreased grasping strength but improved performance. Haptic feedback will be implemented in future revisions after development of kinesthetic feedback is added. A periscopic control station is used by the physician for the custom master device in the master–slave system with visual imaging used for navigation.

Avatera [21] is based on a 4-arm robot platform design with interchangeable tools. Avatera is still in early development so little is known as to whether haptic feedback or monitoring systems will be used. Imagery shows a control unit with an HD monitor for open display as well as a periscopic side periphery.

ARTAS [22] is a hair restoration robot developed by Restoration Robotics Inc. It restores hair to a patient's head through the transplantation of hair follicles. A dissecting punch removes sections of healthy hair follicles and grafts the hair by inserting the plugs at the transplant location. A robot arm and guidance system determine the angle and location of the operating tool while following the doctor's operative plan. ARTAS operates via a monitoring mode system with a standard master device that allows control through a keyboard or touch interface. The robot arm acts as a telemanipulator and operates semiautonomously.

Canady Hybrid Plasma Scalpel [23] is also a laparoscopic surgical robot. Canady Robotic Surgical System's primary tools are the Canady Flex Lapo Wrist and Canady Hybrid Plasma Scalpel. The Lapo Wrist is a 7 DOF, directly operated surgical instrument with a grasping tool at the end. The Plasma Scalpel delivers a beam that simultaneously cuts and coagulates the operating tissue. Canady Robotic Surgical System is neither haptic nor monitoring, as the physician receives optical feedback from an endoscope. The Canady is a true hands-on system with the physician directly manipulating the instruments.

Overall, master and slave type surgical robots are found in large numbers due to the fact that they combine the performance and precision of a robot while allowing the surgeon, who is skillful in performing that particular surgical activity, to maintain overall control.

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Haptics in Surgical Robots

Peter Culmer , ... David Jayne , in Handbook of Robotic and Image-Guided Surgery, 2020

15.2.2.1 General surgery: Senhance

Senhance is a surgical robot platform developed for laparoscopy, originally conceived and developed by the Joint Research Centre of the European Commission in collaboration with SOFAR SpA (Italy) as the Telelap Alf-x and subsequently rebranded as Senhance surgical robot system when the technology was acquired by TransEnterix (Morrisville, North Carolina, United States). The system was approved for general surgical procedures in Europe in 2012 and obtained FDA approval for the United States in 2017 [55,57].

There is little detailed technical information on the Senhance system, but the capabilities of the system can be inferred from a series of publications evaluating its clinical efficacy (see Section 15.2.3). The system was designed to be both cost-effective and to minimize disruption to existing operating theater environments and workflows. Instruments are held by a series of up to four robot arms, each situated on individual mobile carts to allow a flexible configuration around the patient. Senhance promotes that its instruments are similar to those used in manual laparoscopy, designed to promote familiarity with the surgeon they also lack the additional "wristed" degrees of freedom (DoFs) found in competing systems like da Vinci [58]. The surgeon sits at a console providing three-dimensional (3D) visualization, eye-tracking control of the endoscope, and haptic feedback via two force feedback manipulators which resemble laparoscopic instruments [55,57]. The manipulators transmit grasp force, enabling tissue consistency, or object manipulation, to be felt by the surgeon [57]. It is reported that the capabilities are instructive during thread and needle manipulation when suturing [58].

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Robotics for minimally invasive surgery (MIS) and natural orifice transluminal endoscopic surgery (NOTES)

J. Reynoso , ... D. Oleynikov , in Medical Robotics, 2012

9.3 Natural orifice transluminal endoscopic surgery (NOTES)

Natural orifice transluminal endoscopic surgery (NOTES) utilizes natural orifices to access the peritoneal cavity. The feasibility of the NOTES technique was demonstrated in animal studies utilizing peroral gastrotomy, transurethral cystotomy, transvaginal and transcolonic approaches. several procedures including organ resection, gastrojejunostomy, gastrojejunal anastomosis, oopherectomy, salpingectomy, cholecystectomy and appendectomy have been performed in animal studies. NOTES cholecystectomy, appendectomy and nephrectomy have since been performed in humans (santos and Hungness, 2011).

Initially, a standard flexible endoscope was introduced through a NOTES incision, to visualize the intraperitoneal cavity. This approach has several inherent limitations when compared with open or laparoscopic surgery. Triangulation is lost when the standard endoscopic channels are used, as the instruments passed though these ports are in line with the videoimaging. In this configuration, forces must be applied off-axis in order to combat this limitation. one is also limited by the available instruments that may pass through the endoscope. Dexterity is significantly decreased owing to the constraints of this platform. To overcome these constraints, prototypes such as the EndoSAMURAI (Olympus Corp., Tokyo, Japan) have been developed. This endoscopic platform has two independent end effectors with five degrees-of-freedom, as well as a standard endoscopic channel. The operator interface includes controllers which are very similar in design to standard laparoscopic handles. An overtube has been used with this device to increase stability. The EndoSAMURAI has been used in NOTES porcine cholecystectomy via the transgastric approach and has been demonstrated in benchtop experiments to be able to perform surgical tasks such as suturing and knot-tying (Spaun et al., 2009). The TransPort multichannel access device (USGI Medical, san Clemente, CA, USA) is an endoscope with four ports (6, 6, 4 and 4 mm) available for passing flexible instruments. This device has been used in clinical studies to perform transgastric appendectomy, transumbilical appendectomy and endoluminal pouch and stoma reduction (Horgan et al., 2011). The Anubiscope (Karl-storz, Tuttlingen, Germany) is a flexible endoscopic platform for NOTES that has a light and video source. The articulating head contains two opposing movable arms, capable of triangulation, that contain two 4.2 mm working channels. The distal head has jaws that open to reveal the functioning arms but when closed serve as a blunt tipped trocar during insertion (Dallemagne and Marescaux, 2010). The Direct-Drive Endoscopic System (Boston Scientific, Natick, MA, USA) has three lumens through which interchangeable 4 mm flexible instruments can be inserted. Available flexible instruments include graspers, scissors, needle drivers and cautery. This flexible laparoscopic multitasking platform is capable of seven degrees of freedom. This device is controlled by rail-guided drive handles and has a sheath that can lock into position (Shaikh and Thompson, 2010).

The master and slave translumenal endoscopic robot (MASTER) developed by Phee et al. (2010) at the National University of Singapore represents another novel solution to the decreased dexterity inherently found in the endoscopic NOTES platform. It is similar to the EndoSAMURAI in that it has two robotic arms which cap the end of an endoscope. However, with the MASTER, any standard upper endoscope may be outfitted with these robotic arms that are capable of tissue manipulation, triangulation, off-axis forces and monopolar cautery. Mechanical forces are applied to the end effectors through a tendon-sheath power transmission mechanism which allows for nine degrees of freedom. The surgical interface is a 'passive, steerable, motion-sensing exoskeleton with two articulating arms'. The surgeon's hand and wrist movements are directly mirrored by the robotic grasper and cautery end effectors. In a porcine animal study, this system was able to perform a transgastric hepatic wedge resection with minimal bleeding. All imaging and lighting was provided by a standard upper endoscope. A sterile endotube was placed through the esophagus. The gastrotomy was created using the monopolar cautery of the robotic arm. The standard upper endoscope was retroflexed in the peritoneal cavity to provide the surgical robot access to the liver. Tissue retraction provided access for the robotic cautery arm to excise a suitable liver sample. The specimen was then extracted though the mouth. The gastrotomy was not closed in this non-survivable animal study ( Phee et al., 2010).

The standard NOTES flexible endoscope platform is unstable, and forces applied to the target organ are transmitted to the endoscope. This results in a need to continually reposition the endoscope. To overcome the instability produced by flexible endoscopes passed through a hollow lumen, fixation and stiffening of the endoscope has been employed. A flexible robotics platform aims to drive a stiffened endoscope through a 3D space with computer assistance. At the Stanford University School of Medicine, a prototype has been demonstrated by Eisenberg et al. (2010) to be feasible in cadaver studies in which a multichannel flexible robotic endoscope was navigated using a joystick interface. Transgastric intraperitoneal access was achieved, and the platform was able to tolerate forces generated by tissue manipulation and endoclipping. Imaging was provided by the endoscope for this study. Additionally, the endoscope was repositioned without difficulty for access to different target organs.

The dVSS has been used to perform a robot-assisted NOTES nephrectomy in a porcine model, although an additional transabdominal port was placed for laparoscopic visualization. Intraperitoneal access was achieved via transvaginal and transcolonic placement of the robotic arms. The renal artery and vein were dissected using the robot and then transected using standard vascular endoscopic staplers through the vaginal port. The kidney was removed through the vagina. The NOTES technique with the dVSS was also utilized for a porcine pyeloplasty.

Use of the dVSS for NOTES has been confined to animal study and has not been used to date in humans. Although the surgical system provides several advantages, such as multiple degrees of freedom, increased dexterity and stereovision, its size has precluded a widespread application of the dVSS for NOTES. Additionally, the robotic arms are prone to collide and do not conform to the geometry of the intraperitoneal space. For this reason, novel prototypes, as described below, have been created to further develop a robotic platform for NOTES.

9.3.1 Miniature surgical robots for NOTES

Miniature in vivo surgical robots offer an alternative solution to the inherent limitations of NOTES. As previously mentioned, the flexible endoscopic and flexible robotics platform for NOTES are constrained by the distribution of instruments through a hollow visceral lumen into the abdominal cavity while still coupled to external control. Multiple miniature robots may be serially deployed through a single transvisceral access, allowing for a virtually unlimited number of surgical instruments. in this paradigm each miniature robot can serve a separate function, a distinct advantage over any single instrument that must provide all functionality. separate robots may provide imaging, lighting, tissue manipulation, and mobility. A family of these robots can cooperate to perform a NOTES procedure, and have done so in experimental models ( Tiwari et al., 2010). standard upper endoscopes have been used to place an esophageal overtube through which these miniature robots have been sequentially placed in the stomach and then into the abdominal cavity. The gastrotomy is created with a standard endoscopic needle knife.

Initial prototypes of in vivo miniature robots for NOTES included a fixed-base imaging robot meaning, once placed, it was unable to self navigate to an alternative intraperitoneal position. The creation and use of the pan and tilt camera has resolved this navigational barrier. This 15 mm metallic cylinder has three retractable legs, which provide stability when this device is placed on its end. Two independent motors afforded 360° panning and 45° tilting capability. However, the motor originally used for the panning mechanism was later employed for image focusing. visual feedback from this instrument was used in a porcine cholecystectomy.

Advancing this technology further are self navigating, mobile robots powered by two helical-profiled wheels. Each wheel moves independently, allowing for forward, reverse and turning motions. initial prototypes included a cylindrical robot that measured 15 mm in diameter and 75 mm in length (Fig. 9.3). The small diameter allows this mobile imaging robot to be easily deployed through a transgastric incision or a small abdominal incision. The safety and feasibility of this design was demonstrated in animal studies. The next prototype of this design included a camera, and the diameter was increased to 20 mm. The mobile adjustable-focus robotic camera (MARC) was able to transverse the deformable intraperitoneal cavity utilizing the dual helical-profiled wheel design. During a porcine cholecystectomy, this miniature imaging robot supplied the sole video required to complete the procedure.

In a subsequent prototype, the mobile in vivo surgical imaging robot was augmented with a 2.4 mm wide robotic grasper. All of the imaging and mobility capabilities inherent in previous designs were present in this design. The force generated from powered wheels was sufficient to procure a tissue biopsy. The camera on this miniature robot was used for visual feedback while selecting a porcine hepatic biopsy site. This robot was deployed in animal studies through the abdominal wall and demonstrated self navigation, imaging and tissue biopsy capability.

The mobile endoluminal robot was the first in vivo miniature surgical robot to be used in a NOTES procedure. In a porcine study, a standard upper endoscope was introduced per ora into the stomach, and a sterile esophageal overtube was placed with direct visualization. The 12 mm (diameter) and 75 mm (length) miniature robot explored the gastric cavity under endoscopic imaging. A gastrotomy was created with an endoscopic needle-knife and this robot was placed into the intraperitoneal space. Utilizing the same helical-profiled wheels design, the robot was able to self navigate over the liver and the deformable territory of the porcine intestines. Visualization was provided via the endoscope. After this robot was retracted back into the stomach, the gastrotomy was closed with two standard endoclips and one endoloop.

In vivo co-operative robots represent the next step in NOTES prototypes. In this concept, the functions of imaging, lighting and tissue manipulation are executed separately by a family of robots. As previously demonstrated, these miniature robots were deployed into the porcine intraperitoneal space through a sterile esophageal overtube. A standard upper endoscope was used to create a gastrotomy using a needle-knife. The lighting, imaging and retraction robots were serially placed into the abdominal cavity and held in place against the abdominal wall using magnets. Using this technique, the family of co-operative robots was able to manipulate tissue under their own lighted imaging. These initial prototypes were tethered by wires for both power source and control. Currently in development at the University of Nebraska are in vivo miniature robots, powered by on-board batteries and radio-controlled.

These initial NOTES porcine experiments included miniature robots with minimal ability to manipulate tissue. The in vivo dexterous robot was designed to improve dexterity. Six degrees of freedom were achieved with two arms attached to a central body. One arm was fitted with monopolar cautery and the other a grasper. Triangulation is made possible by stereovision cameras placed on the body of the robot between the two arms. A lower arm telescopes in and out of the upper arm, which is attached to the body via a rotational shoulder joint. Robotic arms were remotely controlled at a surgical console consisting of two analog joysticks and a foot pedal that controlled the monopolar cautery. The feasibility of NOTES cholecystectomy was demonstrated over several animal studies. Transabdominal and transgastric placement were both employed. Using the onboard imaging, the porcine gallbladder was dissected free from its hepatic attachments and the cystic duct was severed. Transabdominal magnets were used to maintain the robot's position. The ability to triangulate, apply off-axis forces, provide visualization and dexterously manipulate tissue was demonstrated in these in vivo dexterous robot animal studies.

As previously mentioned, in current prototypes of this multifunctional dexterous robot, the SILS technique has been employed. The proficiency of both the surgical robot and the surgical console has increased significantly, and complex tasks such as intracorporeal suturing are now possible. Continuing design of this robot includes decreasing size, increasing the capability of the surgical interface, and expanding the surgical applications to more complex procedures such as colectomy.

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S-Surge: A Portable Surgical Robot Based on a Novel Mechanism With Force-Sensing Capability for Robotic Surgery

Uikyum Kim , ... Hyouk Ryeol Choi , in Handbook of Robotic and Image-Guided Surgery, 2020

16.5 Implementation

16.5.1 Surgical manipulator

We implemented the surgical robot using the designs of the above robots and instruments. Fig. 16.9 shows an assembled RCM manipulator with three-DoF motion forming a cone with a vertex angle of 90 degrees.

The robot consists of three brushless DC (BLDC) motors and four DC motors for controlling the RCM robot and instrument, respectively, controlled in position control manner. Three 8-W BLDC motors are used as linear actuators (EC-max 16, Maxon Motor AG, Switzerland). BLDC motors were chosen because of their high power density, which provides 8 W of continuous power at a 16-mm diameter. For linear motion, we use a commercial ball-screw mechanism (Spindle drive GP 16, Maxon Motor AG, Switzerland), which includes a 5.4:1 planetary gear head. For angular and insertion movements, the ball screws have a pitch of 2 mm and a length of 200 mm. We use a three-channel 512-pulse/speed encoder for position measurement (MR, Maxon Motor AG, Switzerland). The linear motion has a resolution of 256 pulses/mm. For the position control of BLDC motors, we use a commercial motor controller (EPOS2, Maxon Motor AG, Switzerland).

Then, in the manipulator, we include the drive module for the actuation unit of the instrument. From Fig. 16.9, we use grooves to transmit power to the joints of the instrument. Fig. 16.9 shows how four DC motors (DC1724, Faulhaber Mini-Motor SA, Switzerland) are embedded in the drive module to start the instrument. The DC motor is also controlled by two position controllers embedded in the drive module. The DC motor is controlled by an embedded position controller in the instrument drive unit. Owing to the limited space of the instrument drive unit, we developed a new DC motor controller that can control dual DC motors in a single circuit. As a driver, we use the L6205, a DMOS dual full-bridge driver (ST Micro, United States); it can provide 2.8 A for each channel. For controller chips, we use an STM32F103 (ST Micro, United States) microcontroller, which has a Cortex M3 architecture and operates at 70 MHz. We perform the position control of the DC motors based on a traditional proportional-integral derivative control scheme. In order to drive four DC motors, two of the controller's drive units are stacked. In addition, three low-level controllers for linear actuators are connected to the host PC using universal serial bus (USB) communication (version 2.0). Two DC motor controllers use a control area network (CAN) for communication between high-level controllers.

For linear actuators, we connect three low-level controllers to the host PC using a USB link (version 2.0). Two DC motor controllers use CAN to communicate between the high-level controllers. Similarly, the force sensor controller shares the CAN bus to transmit the measured force information to the high-level controller.

16.5.2 Sensorized surgical instrument

Fig. 16.10 shows an assembled sensor surgical instrument for mounting a four-axis force-sensing system. To measure the force sensing, a three-axis force sensor and two torque sensors are integrated into the wrist and actuation unit, respectively. Four joints (rolling, wrist, and two gripping joints) are placed at the end of the instrument. Based on the tendon-driven actuation mechanism, the joints and pulleys in the actuation unit are connected by a drive cable. The range of motion and transmission of each joint are shown in Table 16.2. Furthermore, the information about the drive module of the instrument joint is explained above. The knobs shown in Fig. 16.10 are used to receive power from the drive module of the manipulator.

The capacitance generated in the sensor is measured by a single-chip configuration of a capacitance-to-digital converter (AD7147, Analog Devices Inc., MA). The sampling frequency and sensing range are 1.3 kHz and 16 pF, respectively. The chip is integrated in the sensor. Fig. 16.10 shows the implemented force sensor controller. In the controller, we use an STM32F103 controller chip as the controller chip. The controller contains two I ² C channels that detect the measured force from the three-axis force sensor and two torque sensors.

16.5.3 Entire surgical robot: S-surge

Fig. 16.11 shows an assembled surgical robot consisting of an RCM manipulator and instrument. The robot has seven-DoF motion and four-axis force sensing. It weighs 4.7 kg and measures 34×18×20 cm³. Table 16.3 lists the detailed specifications of the robot.

Table 16.3. Specifications of the developed surgical robot.

Quantity	Value
Weight	4.7 kg
Maximum workspace	90 degrees circular cone (radius of 15 cm)
Degrees of freedom	7
Force sensing	Four-axis force
Power consumption	34 W

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Robotic Retinal Surgery

Emmanuel Vander Poorten , ... Iulian Iordachita , in Handbook of Robotic and Image-Guided Surgery, 2020

36.5.7 General considerations with respect to safety and usability

Regardless of the surgical robot used, there is still a risk of human error, which may lead to iatrogenic trauma and blindness. For example, excessive tool pivoting around the entry incision may lead to astigmatism, wound leak, or hypotony. Accidental motions of the tool may still puncture the retina or cause bleeding, or even touch the intraocular lens and cause a cataract [180]. All of these risks are indeed present, since the previously described robotic systems do not demonstrate "intelligence," they merely replicate or scale-down the motions of the commanding surgeon. Thus, robots can improve surgical dexterity but not necessarily surgical performance. Functionalization of the tools with force or pressure sensors, as well as ophthalmic image processing, can improve the perception of the surgeon and enable him/her to link with artificial intelligence algorithms toward further improving the success rate of interventions.

A typical step in retinal surgery is a rotation of the eye in its orbit to visualize different regions of the retina. This is accomplished by applying forces at the scleral trocars with the instrument shafts. When done bimanually, surgeons have force feedback to ensure that their hands are working together to accomplish the rotation, without putting undue stress on the sclera. When using more than one robotic manipulator in retinal surgery, whether in a cooperative or teleoperated paradigm, the control system must ensure that the robots work in a coordinated fashion. This kinematically constrained problem is solved in Ref. [142].

Further, all teleoperation systems and especially systems using curved and shape-changing instruments or untethered agents require retraining of the surgical personnel to get accustomed to this remote-manipulation paradigm, which may disrupt surgical workflow. Many of the master interfaces have been designed to make this transition as intuitive as possible, and are based on either recreating the kinematic constraints of handheld and cooperative-control systems (i.e., with the surgeon's hand on the instrument handle outside of the eye) or on creating kinematics that effectively place the surgeon's hand at the end-effector of the instrument inside the eye (with the kinematic constraint of the trocar explicitly implemented in the interface). However, recent work suggests that placing the surgeon's hand at the end-effector of the instrument, but not explicitly presenting the kinematic constraints of the trocar to the user, may lead to improved performance, likely due to the improved ergonomics that it affords [181].

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Slender snake-like endoscopic robots in surgery

Shumei Yu , ... Hongliang Ren , in Flexible Robotics in Medicine, 2020

1.3.2 Statics and dynamics

A snake-like surgical robot's static modeling solves the relationship of the force, moment, and deformation. For tendon-driven snake-like surgical robots, statics is usually combined with kinematics when Cosserat Rod Theory is applied in the modeling. Based on Cosserat Rod Theory, Gao et al. [17] built a shape prediction model for a helical spring backboned snake robot, in which the deformation of the robot is related to the tendon force, friction force, and external forces. Lumped-parameter model is an alternative basis for static analysis, for example, Kato et al. [16] built the tension propagation model with friction between the wires and the robot body. The principle of virtual work was used to compute the actuation force on building a load transmission model in the work of Roy et al. [48]. Dong et al. [29] analyzed the cable tension and stiffness of a compliant joint backboned snake robot based on the Jacobian. A dynamic model to compensate for the uncertainty and asymmetry has been proposed by Haraguchi et al. [31] by defining the driving forces related to the bending angle, friction force, and elastic forces.

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Single-port multichannel multi-degree-of-freedom robot with variable stiffness for natural orifice transluminal endoscopic surgery

Changsheng Li , ... Hongliang Ren , in Flexible Robotics in Medicine, 2020

17.2.2 System overview

Fig. 17.1 presents a surgical robot with variable stiffness for NOTES. This robot is composed of two same manipulators attached to an endoscopic platform and a driver. The endoscopic platform has two channels with the diameters of 2.8 and 3.8 mm for surgical tools, respectively, a channel for the camera, and two channels for the air/water nozzle. The diameter of each manipulator is 3.6 mm, with 6 DOFs. The distribution of the manipulator DOFs in Fig. 17.2 includes three parts: a compliant arm, a flexible wrist joint, and a gripper. The stiffness of the compliant arm with 2 DOFs can be tuned in real-time during the operation to fulfill the accuracy and safety requirements of the surgery environment. The wrist joint is flexible with 1 DOF. The gripper can bend in a broad range with 2 DOFs. A screw motor–based driver drives the manipulators via Bowden cables. The main parameters of each manipulator are summarized in Table 17.1.

Table 17.1. Main parameters of the robotic system.

Parameters	Values	Units	References
Channels	3	–	A minimum of three endoscopic channels [15]
Length	40	mm	–
The diameter of the manipulator	3.6	mm	The size of the current robotics for NOTES mainly ranges from ∅5 to ∅14 [16]
Bending angle of the arm	30	Degrees	–
Bending angle of the wrist joint	±90 degrees	–	–
DOF	6 for each manipulator	–	DOFs should not be less than 4 [14]
Drive mode	Bowden cable	–	–
Material	45# steel	–	–
Features	Compliance; variable stiffness	–	–

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