Mechanical manipulator for surgical instruments

A novel mechanical system, based on a new cable driven mechanical transmission, able to provide sufficient dexterity, stiffness, speed, precision and payload capacity to actuate multi-DOF micro-manipulators. Besides the possibility of being used in several articulated surgical instruments and robotic systems for surgery or other applications involving remote manipulation, it enables the design of a novel fully mechanical surgical instrument, which offer the advantages of conventional laparoscopy (low cost, tactile feedback, high payload capacity) combined with the advantages of single port surgery (single incision, scarless surgery, navigation through several quadrants of the abdominal cavity) and robotic surgery (greater degrees of freedom, short learning curve, high stiffness, high precision, increased intuition). The unique design of the proposed system provides an intuitive user interface to achieve such enhanced manoeuvrability, allowing each joint of a teleoperated slave system to be driven by controlling the position of a mechanically connected master unit.

Design of Dexterous Mechanical Systems for Intuitive Telemanipulation in Minimally Invasive Surgery

Ricardo Daniel Rita Beira

Major progress in abdominal surgery has occurred over the last decades with the introduction of laparoscopic and minimally invasive techniques in the operating room. These innovative procedures attracted much attention due to several advantages: the need for smaller abdominal incisions resulting in faster recovery of the patient, improved cosmetics, shorter hospitalization and a significant reduction of costs. However, surgical instrumentation for this type of intervention still remains non-intuitive and much more difficult to use than tools for open surgical procedures. As a consequence, these minimally invasive techniques are limited to fairly simple procedures. Due to the landscape of medical reimbursement, there is a substantial push by insurance companies, health care organizations and hospitals to extend minimally invasive techniques to a wider range of surgical procedures in order to reduce hospital stays and therefore costs. In order to respond to these demands, a strong research effort has been made over the past years on the development of enabling minimally invasive technologies, mainly through the introduction and development of robotic systems. Surgical robots significantly contribute to the improvement of the surgical performance by increasing the dexterity and user-friendliness of surgical procedures through the use of robotic telemanipulation. However, despite years of research, the field of surgical robotics is still only at the beginning of a very promising large scale development. Although a large number of systems have been developed, several issues are not yet addressed, limiting the adoption of surgical robots by a broader range of hospitals. A major limitation is related to the lack of internal dexterity, caused by the mobility constraints imposed by the small entry port. On one hand, it is important to increase the dexterity of the end-effectors inside the body, overcoming the issues of limited manoeuvrability in the abdominal cavity. On the other hand, the system must be introduced through conventional trocars, which are small in diameter. The management of this trade-off is extremely challenging, making the development of dexterous micro-manipulators one of the most important issues in the field of robotic systems for surgery. Another limitation is that the current surgical robots are voluminous, competing for precious space within the operating room and significantly increasing the complexity of operating room logistics. Access to the patient is thus impaired, which raises safety concerns. Furthermore, due to the physical separation from the operating area and lack of force-feedback on the existing surgical systems, surgeons cannot feel the contact forces between instruments and tissue. This limitation may cause long operating times and unintentional damage of tissue and suturing material. Although bringing several technical advantages for surgeons, current robotic systems are extremely expensive in acquisition, maintenance, disposable tools and training, representing much higher direct costs compared with open surgery and laparoscopic instrumentation. For this reason, access to robotic surgery is limited to a minority of hospitals that can afford to purchase such systems and have enough patient volume to justify the acquisition. This tendency towards centralisation of complex minimally invasive surgeries draws patients from hospitals without surgical robots and places a significant burden on the healthcare system. This thesis investigates novel mechanical systems to be used in different surgical telemanipulators, solving the limitations of existing robotic and manual surgical equipment, in three main areas: patient safety, surgical dexterity and health care cost. This can be achieved by providing the surgeon with more compact systems comprising new multi-DOF micromanipulators, and new mechanical telemanipulators able to deliver dexterous manipulation through a more affordable technology. These objectives implied not only an investigation of technical aspects such as the performance requirements of surgical tools, but also the investigation of the different medical procedures and surgical tasks used by doctors during minimally invasive interventions. Although, the solutions studied in this thesis have been applied in the context of surgical systems for minimally invasive surgery, the outcome of this research can be extended to several other application fields. From a general perspective, the goal of this thesis is to propose a document which may be useful and inspiring for machine designers, developers, or scientists who wish to create efficient remotely controlled manipulators for several applications involving multi-DOF manipulation.

EPFL2013

Control of Contact Tasks in Autonomous and Human-Robot Collaborative Scenarios: A Dynamical System Approach

Walid Amanhoud

Robotic systems are more and more present in our daily life. Robots became indeed more economical, easy to program, safe and collaborative in their interaction with humans, versatile in performing different tasks and adaptive towards changes in the environment. Despite the recent advances in robotics, developingfully autonomous robots to achieve complex industrial or daily-life tasks is still very challenging. The human, due to his superior perception, understanding and reasoning skills, especially in uncertain environment, needs to be in the loop. Therefore, the ability of robots to collaborate with humans is of great interest inthe robotics community. Human-Robot Collaboration usually implies robots that share the control of the tasks with humans, providing adjustable autonomy level and mutual adaptation. A field that can particularly benefits from such collaboration is assistive robotics surgery. The introduction of shared autonomyin surgical tasks has several advantages. In particular, it can provide higher accuracy, flexibility, control and efficiency during the operation, over longer time periods, relieve the surgeon during repetitive tasks and reduce his mental workload. However, it is not very clear how to best use shared control to assist asurgeon during the operation. As part of a research project (the "Surgical project"), in this thesis we would like to propose solutions to that problem by building a teleoperated shared control architecture for a laparoscopic surgery scenario. While laparoscopic surgery usually involves one surgeon and two humanassistants to perform the surgery, the project aims to replace the assistants by two partially teleoperated robotic systems. The target shared control architecture would explore various strategies to ensure safety for both the patient and the surgeon, provide accuracy and stability in motion and force control of the toolsattached to the robots, reduce the mental workload of the surgeon and adapt the level of assistance based on well-identified criteria.The first year was mainly devoted to the control of motion and force for contact tasks which is of great importance in the context of the project. Robot force control is traditionally achieved either explicitly through hybrid position/force control or implicitly using impedance control. We propose an approach leveraging theproperties of dynamical systems (DS) for immediate re-planning and robustness to real-time perturbations by exploiting local modulation of the DS. Dynamical systems has been widely used as a tool to represent and generate motion in robotics application. Here the idea is to propose a DS formulation to generatecontact force in addition to motion. First implementation and experiments to evaluate the effectiveness of the strategy were conducted in practice with a 7-DOF robotic arm (KUKA LWR IV+).So far we focused on contact tasks that were performed autonomously by one or two robots. Future work will improve and use the proposed DS approach to consider contact tasks in shared control scenarios where one human and one or two robots need to collaborate to successfully achieve the tasks. Because of the nature of the surgical project we will use teleoperation systems to introduce the human in the loop. The developed teleoperated shared control architecture will be evaluated on laparoscopic surgery related tasks.

EPFL2021

Active origami platforms for human-robot interactions

Frédéric Henri Vaskin Giraud

Robots are employed to assist humans in lengthy, challenging, and repetitive tasks. However, the fields of rehabilitation, haptics, and assistive robotics have shown a significant need to support and interact with people in their everyday life. To facilitate these further needs, robots must overcome constraints in compactness, degrees of freedom (DoF), and mechanical performance. However, developing a robot with these characteristics is challenging for conventional mechanics. First, creating a meso-scale device requires the assembly of small components, which is laborious and increases manufacturing cost, time, and complexity. In addition, devices with several DoF and functionalities also require more parts to create numerous links and joints, actuators, and thus space, affecting the compactness of systems. Finally, aiming for mechanical performance in terms of force, speed, and motion range requires transmissions or bulky actuators, which also influence the size of the system. This thesis attempts to overcome the limitations of conventional mechanics by using origami robots, an alternative design approach for creating meso-scale structures with numerous folding joints. It consists in stacking layers of functional material to achieve low-profile and scalable structures that fold into 3D. Using this method, we developed three hybrid robots combining the decades of experience of conventional mechanics with the advantages of origami robotics. First, to enhance the performances of robots at the meso-scale, the creation of compact low-profile compliant transmissions benefiting from origami's minimal assembly of functional layers was explored. The transmissions obtained can reproduce conventional kinematics or generate unconventional motions using materials properties. Second, the development of multi-DoF compact robots was studied using the aforementioned low-profile compliant transmissions to create a multi-functional structure. The resulting robot is a fingertip haptic device called Haptigami that can render vibrotactile and three-DoF force feedback without compromising bulkiness. Then, this study aimed at creating a meso-scale, multi-DoF, and mechanically efficient robot. We combined the previous device contributions and developed Flexure Variable Stiffness Actuators (F-VSA), a novel compliant actuator that uses the origami flexure hinges' inherent stiffness to avoid hindering mechanical simplicity. Finally, we developed a software architecture that enables high-level control of the human-robot hardware and is compatible with multiple simulation engines. We used this architecture to control our robots and provide feedback to the user, based on interactions in a virtual environment. These novel robots rely on non-conventional structures, actuators, and kinematics that require exploring and testing suitable control strategies. Hence, kinematic and stiffness models were developed and used to tune the position, force, and stiffness of the end-effector. Several characterization platforms and experimental protocols suitable for testing our unique robotic systems were also developed to assess their precision and efficiency. Consequently, the results of this study pave the way for the development of robots that adapt to multiple environments, interactions, and application scenarios, compatible with the human bandwidth without hindering the user's motion and comfort in everyday life.

EPFL2022