Devices fabricated using soft materials have been a major research focus of late, capturing the a... more Devices fabricated using soft materials have been a major research focus of late, capturing the attention of scientists and laypersons alike in a wide range of fields, from microfluidics to robotics. The functionality of such devices relies on their structural and material properties; thus, the fabrication method is of utmost importance. Here, multilayer soft lithography, precision laser micromachining, and folding to establish a new paradigm are combined for creating 3D soft microstructures and devices. Phase‐changing materials are exploited to transform actuators into structural elements, allowing 2D laminates to evolve into a third spatial dimension. To illustrate the capabilities of this new fabrication paradigm, the first “microfluidic origami for reconfigurable pneumatic/hydraulic” device is designed and manufactured: a 12‐layer soft robotic peacock spider with embedded microfluidic circuitry and actuatable features.
Soft pneumatic actuators are promising candidates for micro-manipulation and delicate gripping du... more Soft pneumatic actuators are promising candidates for micro-manipulation and delicate gripping due to their wide range of motion and ease of fabrication. While existing elastomer-based devices have attracted attention due to their compliant structures, there is a need for materials that combine flexibility, controllable actuation, and robustness. This paper bridges this capability gap by introducing a novel fabrication strategy for nanofiber-reinforced soft micro-actuators. The design and manufacturing of composite PDMS/nanofiber actuators using soft lithography and rotary jet spinning is described. We examine the impact of lamina design and fiber orientation on actuator curvature, mechanical properties, and pressurization range. Composite actuators displayed a 25.8% higher maximum pressure than pure PDMS devices. Further, the best nanofiber-reinforced laminates tested were 2.3 times tougher than the control PDMS material while maintaining comparable elongation. Finally, bending and bending-twisting are demonstrated using pristine and laser-patterned nanofiber sheets, respectively.
Flexible endoscopes are still the gold standard in most natural orifice translumenal endoscopic s... more Flexible endoscopes are still the gold standard in most natural orifice translumenal endoscopic surgery (NOTES) procedures; however their flexibility (necessary for navigating through the GI tract) limits their capabilities in terms of distal manipulation and stability. We propose a deployable endoscopic add-on aimed at locally counteract-ing forces applied at the tip of an endoscope. We analyze different designs: a fully soft version and two hybrid soft-folded versions. The hybrid designs exploit either an inextensible structure pressurized by a soft actuator or the stiffness provided by the unfolded " magic cube " origami structure. We focus on the fabrication and experimental characterization of the proposed structures and present some preliminary designs and integration strategies to mount them on top of current flexible endoscopes.
This paper presents the concept design of a modular soft manipulator for minimally invasive surge... more This paper presents the concept design of a modular soft manipulator for minimally invasive surgery. Unlike traditional surgical manipulators based on metallic steerable needles, tendon-driven mechanisms, or articulated motorized links, we combine flexible fluidic actuators to obtain multidirectional bending and elongation with a variable stiffness mechanism based on granular jamming. The idea is to develop a manipulator based on a series of modules, each consisting of a silicone matrix with pneumatic chambers for 3-D motion, and one central channel for the integration of granular-jamming-based stiffening mechanism. A bellows-shaped braided structure is used to contain the lateral expansion of the flexible fluidic actuator and to increase its motion range. In this paper, the design and experimental characterization of a single module composed of such a manipulator is presented. Possible applications of the manipulator in the surgical field are discussed.
This paper introduces a novel, bioinspired manipulator for minimally invasive surgery (MIS). The ... more This paper introduces a novel, bioinspired manipulator for minimally invasive surgery (MIS). The manipulator is entirely composed of soft materials, and it has been designed to provide similar motion capabilities as the octopus's arm in order to reach the surgical target while exploiting its whole length to actively interact with the biological structures. The manipulator is composed of two identical modules (each of them can be controlled independently) with multi-directional bending and stiffening capabilities, like an octopus arm. In the authors' previous works, the design of the single module has been addressed. Here a two-module manipulator is presented, with the final aim of demonstrating the enhanced capabilities that such a structure can have in comparison with rigid surgical tools currently employed in MIS. The performances in terms of workspace, stiffening capabilities, and generated forces are characterized through experimental tests. The combination of stiffening capabilities and manipulation tasks is also addressed to confirm the manipulator potential employment in a real surgical scenario.
This paper introduces a pose-sensing system for soft robot arms integrating a set of macrobend st... more This paper introduces a pose-sensing system for soft robot arms integrating a set of macrobend stretch sensors. The macrobend sensory design in this study consists of optical fibres and is based on the notion that bending an optical fibre modulates the intensity of the light transmitted through the fibre. This sensing method is capable of measuring bending, elongation and compression in soft continuum robots and is also applicable to wearable sensing technologies, e.g. pose sensing in the wrist joint of a human hand. In our arrangement, applied to a cylindrical soft robot arm, the optical fibres for macrobend sensing originate from the base, extend to the tip of the arm, and then loop back to the base. The connectors that link the fibres to the necessary opto-electronics are all placed at the base of the arm, resulting in a simplified overall design. The ability of this custom macrobend stretch sensor to flexibly adapt its configuration allows preserving the inherent softness and compliance of the robot which it is installed on. The macrobend sensing system is immune to electrical noise and magnetic fields, is safe (because no electricity is needed at the sensing site), and is suitable for modular implementation in multi-link soft continuum robotic arms. The measurable light outputs of the proposed stretch sensor vary due to bend-induced light attenuation (macrobend loss), which is a function of the fibre bend radius as well as the number of repeated turns. The experimental study conducted as part of this research revealed that the chosen bend radius has a far greater impact on the measured light intensity values than the number of turns (if greater than five). Taking into account that the bend radius is the only significantly influencing design parameter, the macrobend stretch sensors were developed to create a practical solution to the pose sensing in soft continuum robot arms. Henceforward, the proposed sensing design was benchmarked against an electromagnetic tracking system (NDI Aurora) for validation.
This article introduces a soft and stretchable sensor composed of silicone rubber integrating a c... more This article introduces a soft and stretchable sensor composed of silicone rubber integrating a conductive liquid-filled channel with a biocompatible sodium chloride (NaCl) solution and novel stretchable gold sputtered electrodes to facilitate the biocompatibility of the sensor. By stretching the sensor, the cross section of the channel deforms, thus leading to a change in electrical resistance. The functionalities of the sensor have been validated experimentally: changes in electrical resistance are measured as a function of the applied strain. The experimentally measured values match theoretical predictions, showing relatively low hysteresis. A preliminary assessment on the proposed sensor prototype shows good results with a maximum tested strain of 64%. The design optimization of the saline solution, the electrodes, and the algebraic approximations derived for integrating the sensors in a flexible manipulator for surgery has been discussed. The contribution of this article is the introduction of the biocompatible and stretchable gold sputtered electrodes integrated with the NaCl-filled channel rubber as a fully biocompatible solution for measuring deformations in soft and stretchable medical instruments.
ABSTRACT This paper presents the design of a single module composing a modular soft variable stif... more ABSTRACT This paper presents the design of a single module composing a modular soft variable stiffness manipulator for minimal access surgery. The module exploits flexible fluidic actuation for obtaining multi directional bending and elongation capabilities. A novel flexible crimped braided sheath is introduced in order to increase the performances of the flexible actuator. Granular jamming based stiffening mechanism is used to tune the stiffness of the module. The fabrication of the module is described and the performances in terms of bending, elongation and stiffening are reported.
This paper describes the design and
development of a modular soft manipulator for
minimally invas... more This paper describes the design and development of a modular soft manipulator for minimally invasive surgery, which equals the high dexterity of classic hyper redundant continuum, but rigid, robots resulting in safer potential interaction with internal organs. The manipulator relies on the use of a soft flexible fluidic actuator in each of its modules, which can be wireless controlled by means of an embedded fluidic control unit. This actuation unit is equipped with three miniaturized latching valves, a wireless microcontroller board, and a specifically designed fluidic distributor integrated into the elastomeric material that the module is made of. FEM simulations and experimental tests verified the reliability of the distributor in acting as a piping system inside each module. The mobility of the fully integrated soft module was evaluated in terms of static performances and covered workspace. The module’s dynamic model during one-chamber motion was estimated from the parameter estimation analysis. The characterization of the single module behaviour is intended as first step to ease the future high level control of the multi-modular architecture.
This paper describes a multi-fingered haptic palpation method using stiffness feedback actuators ... more This paper describes a multi-fingered haptic palpation method using stiffness feedback actuators for simulating tissue palpation procedures in traditional and robot-assisted minimally invasive surgery. Soft tissue stiffness is simulated by changing the stiffness property of the actuator during palpation. For the first time, granular jamming and pneumatic air actuation are combined together to realize stiffness modulation. The stiffness feedback actuator is validated by stiffness measurements in indentation tests and through stiffness discrimination based on a user study. According to the indentation test results, the introduction of a pneumatic chamber to granular jamming can amplify the stiffness variation range and reduce hysteresis of the actuator. The advantage of multi-fingered palpation using the proposed actuators is proven by the comparison of the results of the stiffness discrimination performance using two-fingered (sensitivity: 82.2%, specificity: 88.9%, positive predicative value: 80.0%, accuracy: 85.4%, time: 4.84 s) and single-fingered (sensitivity: 76.4%, specificity: 85.7%, positive predicative value: 75.3%, accuracy: 81.8%, time: 7.48 s) stiffness feedback.
3rd Joint Workshop on New Technologies for Computer/Robot Assisted Surgery 11-12-13 September 2013, Verona, Italy, Sep 13, 2013
This paper presents the design of a single module composing a modular soft variable stiffness man... more This paper presents the design of a single module composing a modular soft variable stiffness manipulator for minimal access surgery. The module exploits flexible fluidic actuation for obtaining multi directional bending and elongation capabilities. A novel flexible crimped braided sheath is introduced in order to increase the performances of the flexible actuator. Granular jamming based stiffening mechanism is used to tune the stiffness of the module. The fabrication of the module is described and the performances in terms of bending, elongation and stiffening are reported.
Devices fabricated using soft materials have been a major research focus of late, capturing the a... more Devices fabricated using soft materials have been a major research focus of late, capturing the attention of scientists and laypersons alike in a wide range of fields, from microfluidics to robotics. The functionality of such devices relies on their structural and material properties; thus, the fabrication method is of utmost importance. Here, multilayer soft lithography, precision laser micromachining, and folding to establish a new paradigm are combined for creating 3D soft microstructures and devices. Phase‐changing materials are exploited to transform actuators into structural elements, allowing 2D laminates to evolve into a third spatial dimension. To illustrate the capabilities of this new fabrication paradigm, the first “microfluidic origami for reconfigurable pneumatic/hydraulic” device is designed and manufactured: a 12‐layer soft robotic peacock spider with embedded microfluidic circuitry and actuatable features.
Soft pneumatic actuators are promising candidates for micro-manipulation and delicate gripping du... more Soft pneumatic actuators are promising candidates for micro-manipulation and delicate gripping due to their wide range of motion and ease of fabrication. While existing elastomer-based devices have attracted attention due to their compliant structures, there is a need for materials that combine flexibility, controllable actuation, and robustness. This paper bridges this capability gap by introducing a novel fabrication strategy for nanofiber-reinforced soft micro-actuators. The design and manufacturing of composite PDMS/nanofiber actuators using soft lithography and rotary jet spinning is described. We examine the impact of lamina design and fiber orientation on actuator curvature, mechanical properties, and pressurization range. Composite actuators displayed a 25.8% higher maximum pressure than pure PDMS devices. Further, the best nanofiber-reinforced laminates tested were 2.3 times tougher than the control PDMS material while maintaining comparable elongation. Finally, bending and bending-twisting are demonstrated using pristine and laser-patterned nanofiber sheets, respectively.
Flexible endoscopes are still the gold standard in most natural orifice translumenal endoscopic s... more Flexible endoscopes are still the gold standard in most natural orifice translumenal endoscopic surgery (NOTES) procedures; however their flexibility (necessary for navigating through the GI tract) limits their capabilities in terms of distal manipulation and stability. We propose a deployable endoscopic add-on aimed at locally counteract-ing forces applied at the tip of an endoscope. We analyze different designs: a fully soft version and two hybrid soft-folded versions. The hybrid designs exploit either an inextensible structure pressurized by a soft actuator or the stiffness provided by the unfolded " magic cube " origami structure. We focus on the fabrication and experimental characterization of the proposed structures and present some preliminary designs and integration strategies to mount them on top of current flexible endoscopes.
This paper presents the concept design of a modular soft manipulator for minimally invasive surge... more This paper presents the concept design of a modular soft manipulator for minimally invasive surgery. Unlike traditional surgical manipulators based on metallic steerable needles, tendon-driven mechanisms, or articulated motorized links, we combine flexible fluidic actuators to obtain multidirectional bending and elongation with a variable stiffness mechanism based on granular jamming. The idea is to develop a manipulator based on a series of modules, each consisting of a silicone matrix with pneumatic chambers for 3-D motion, and one central channel for the integration of granular-jamming-based stiffening mechanism. A bellows-shaped braided structure is used to contain the lateral expansion of the flexible fluidic actuator and to increase its motion range. In this paper, the design and experimental characterization of a single module composed of such a manipulator is presented. Possible applications of the manipulator in the surgical field are discussed.
This paper introduces a novel, bioinspired manipulator for minimally invasive surgery (MIS). The ... more This paper introduces a novel, bioinspired manipulator for minimally invasive surgery (MIS). The manipulator is entirely composed of soft materials, and it has been designed to provide similar motion capabilities as the octopus's arm in order to reach the surgical target while exploiting its whole length to actively interact with the biological structures. The manipulator is composed of two identical modules (each of them can be controlled independently) with multi-directional bending and stiffening capabilities, like an octopus arm. In the authors' previous works, the design of the single module has been addressed. Here a two-module manipulator is presented, with the final aim of demonstrating the enhanced capabilities that such a structure can have in comparison with rigid surgical tools currently employed in MIS. The performances in terms of workspace, stiffening capabilities, and generated forces are characterized through experimental tests. The combination of stiffening capabilities and manipulation tasks is also addressed to confirm the manipulator potential employment in a real surgical scenario.
This paper introduces a pose-sensing system for soft robot arms integrating a set of macrobend st... more This paper introduces a pose-sensing system for soft robot arms integrating a set of macrobend stretch sensors. The macrobend sensory design in this study consists of optical fibres and is based on the notion that bending an optical fibre modulates the intensity of the light transmitted through the fibre. This sensing method is capable of measuring bending, elongation and compression in soft continuum robots and is also applicable to wearable sensing technologies, e.g. pose sensing in the wrist joint of a human hand. In our arrangement, applied to a cylindrical soft robot arm, the optical fibres for macrobend sensing originate from the base, extend to the tip of the arm, and then loop back to the base. The connectors that link the fibres to the necessary opto-electronics are all placed at the base of the arm, resulting in a simplified overall design. The ability of this custom macrobend stretch sensor to flexibly adapt its configuration allows preserving the inherent softness and compliance of the robot which it is installed on. The macrobend sensing system is immune to electrical noise and magnetic fields, is safe (because no electricity is needed at the sensing site), and is suitable for modular implementation in multi-link soft continuum robotic arms. The measurable light outputs of the proposed stretch sensor vary due to bend-induced light attenuation (macrobend loss), which is a function of the fibre bend radius as well as the number of repeated turns. The experimental study conducted as part of this research revealed that the chosen bend radius has a far greater impact on the measured light intensity values than the number of turns (if greater than five). Taking into account that the bend radius is the only significantly influencing design parameter, the macrobend stretch sensors were developed to create a practical solution to the pose sensing in soft continuum robot arms. Henceforward, the proposed sensing design was benchmarked against an electromagnetic tracking system (NDI Aurora) for validation.
This article introduces a soft and stretchable sensor composed of silicone rubber integrating a c... more This article introduces a soft and stretchable sensor composed of silicone rubber integrating a conductive liquid-filled channel with a biocompatible sodium chloride (NaCl) solution and novel stretchable gold sputtered electrodes to facilitate the biocompatibility of the sensor. By stretching the sensor, the cross section of the channel deforms, thus leading to a change in electrical resistance. The functionalities of the sensor have been validated experimentally: changes in electrical resistance are measured as a function of the applied strain. The experimentally measured values match theoretical predictions, showing relatively low hysteresis. A preliminary assessment on the proposed sensor prototype shows good results with a maximum tested strain of 64%. The design optimization of the saline solution, the electrodes, and the algebraic approximations derived for integrating the sensors in a flexible manipulator for surgery has been discussed. The contribution of this article is the introduction of the biocompatible and stretchable gold sputtered electrodes integrated with the NaCl-filled channel rubber as a fully biocompatible solution for measuring deformations in soft and stretchable medical instruments.
ABSTRACT This paper presents the design of a single module composing a modular soft variable stif... more ABSTRACT This paper presents the design of a single module composing a modular soft variable stiffness manipulator for minimal access surgery. The module exploits flexible fluidic actuation for obtaining multi directional bending and elongation capabilities. A novel flexible crimped braided sheath is introduced in order to increase the performances of the flexible actuator. Granular jamming based stiffening mechanism is used to tune the stiffness of the module. The fabrication of the module is described and the performances in terms of bending, elongation and stiffening are reported.
This paper describes the design and
development of a modular soft manipulator for
minimally invas... more This paper describes the design and development of a modular soft manipulator for minimally invasive surgery, which equals the high dexterity of classic hyper redundant continuum, but rigid, robots resulting in safer potential interaction with internal organs. The manipulator relies on the use of a soft flexible fluidic actuator in each of its modules, which can be wireless controlled by means of an embedded fluidic control unit. This actuation unit is equipped with three miniaturized latching valves, a wireless microcontroller board, and a specifically designed fluidic distributor integrated into the elastomeric material that the module is made of. FEM simulations and experimental tests verified the reliability of the distributor in acting as a piping system inside each module. The mobility of the fully integrated soft module was evaluated in terms of static performances and covered workspace. The module’s dynamic model during one-chamber motion was estimated from the parameter estimation analysis. The characterization of the single module behaviour is intended as first step to ease the future high level control of the multi-modular architecture.
This paper describes a multi-fingered haptic palpation method using stiffness feedback actuators ... more This paper describes a multi-fingered haptic palpation method using stiffness feedback actuators for simulating tissue palpation procedures in traditional and robot-assisted minimally invasive surgery. Soft tissue stiffness is simulated by changing the stiffness property of the actuator during palpation. For the first time, granular jamming and pneumatic air actuation are combined together to realize stiffness modulation. The stiffness feedback actuator is validated by stiffness measurements in indentation tests and through stiffness discrimination based on a user study. According to the indentation test results, the introduction of a pneumatic chamber to granular jamming can amplify the stiffness variation range and reduce hysteresis of the actuator. The advantage of multi-fingered palpation using the proposed actuators is proven by the comparison of the results of the stiffness discrimination performance using two-fingered (sensitivity: 82.2%, specificity: 88.9%, positive predicative value: 80.0%, accuracy: 85.4%, time: 4.84 s) and single-fingered (sensitivity: 76.4%, specificity: 85.7%, positive predicative value: 75.3%, accuracy: 81.8%, time: 7.48 s) stiffness feedback.
3rd Joint Workshop on New Technologies for Computer/Robot Assisted Surgery 11-12-13 September 2013, Verona, Italy, Sep 13, 2013
This paper presents the design of a single module composing a modular soft variable stiffness man... more This paper presents the design of a single module composing a modular soft variable stiffness manipulator for minimal access surgery. The module exploits flexible fluidic actuation for obtaining multi directional bending and elongation capabilities. A novel flexible crimped braided sheath is introduced in order to increase the performances of the flexible actuator. Granular jamming based stiffening mechanism is used to tune the stiffness of the module. The fabrication of the module is described and the performances in terms of bending, elongation and stiffening are reported.
This paper introduces a manufacturing technique which enables the integration of soft materials a... more This paper introduces a manufacturing technique which enables the integration of soft materials and soft fluidic micro-actuators in the Pop-up book MEMS paradigm. Such a technique represents a promising approach to the design and fabrication of low cost and scalable articulated mechanisms provided with sensing capabilities and on-board actuation with potential applications in the field of minimally invasive surgery. Design and integration of soft components in the rigid-flex laminates is described along with the resulting soft pop-up mechanisms realized at different scales. Prototype characterization is presented, demonstrating forces and dexterity in a range suitable for surgical applications, as well as the possibility to integrate sensing capabilities. Based on these results, a multi-articulated robotic arm is fabricated and mounted on top of an endoscope model to provide a proof of concept of simple robotic mechanisms that could be useful in a surgical scenario.
This paper presents a new design of worm robot whose body is constructed using a novel crimped el... more This paper presents a new design of worm robot whose body is constructed using a novel crimped elastic mesh braid inspired by the earthworm. The proposed worm robot is intended for inspection within the human body via natural orifices. The design and fabrication procedure of the worm robot are given in the paper. The imitation of peristalsis, used by natural worms, is used to control the worm robot for the purpose of producing motion while causing minimal trauma to biological tissue. The forward locomotive function of the worm robot has been tested on both a flat surface and in a rubber tube. It is shown that the worm robot is capable of propagating forwards for both test conditions in a form similar to the earthworm. The test results indicate the proposed worm robot design has promising application for natural tube inspection, like the colon and the esophagus.
In this paper a simple but effective measuring system for endoluminal procedures is presented. Th... more In this paper a simple but effective measuring system for endoluminal procedures is presented. The device allows measuring forces during the endoluminal manipulation of tissues with a standard surgical instrument for laparoscopic procedures. The force measurement is performed by recording both the forces applied directly by the surgeon at the instrument handle and the reaction forces on the access port. The measuring system was used to measure the forces necessary for appropriate surgical manipulation of tissues during transanal endoscopic microsurgery (TEM). Ex-vivo and in-vivo measurements were performed, reported and discussed. The obtained data can be used for developing and appropriately dimensioning novel dedicated instrumentation for TEM procedures.
Modern surgery is currently developing NOTES
(Natural Orifice Translumenal Endoscopic Surgery) r... more Modern surgery is currently developing NOTES
(Natural Orifice Translumenal Endoscopic Surgery) robotic
approaches to enable scarless surgical procedures. Despite of
the variegated devices proposed, they still have several
limitations. In this work, we propose a surgical platform
composed of specialized modules, in order to provide the
overall system with adequate stability, dexterity and force
generation. The concept behind the platform, the main modules
and their performance are described to highlight the system
potential to outperform current NOTES procedures.
2013 IEEE/RSJ International Conference on Intelligent Robots and Systems; 11/2013
Magnetic driven wireless capsule endoscopy (WCE) represents one of the last achievements in the ... more Magnetic driven wireless capsule endoscopy (WCE) represents one of the last achievements in the research of minimally invasive tools for gastrointestinal tract (GI) diagnosis. Recently, capsule localization methodologies have been employed to enable system autonomy maintaining a magnetic link with the device and managing interaction forces with GI tissues. To achieve these objectives, the locomotion platforms exploit automatic motion in some degrees of freedom and unsupervised contact with the external patient abdomen can occur. In this paper safety issues are faced; in particular a safety system, able to monitor pressure with patient abdomen, has been designed, characterized, and integrated with a magnetic driven WCE locomotion platform. New technologies, such as smart textiles, have been employed as sensible element.
2013 IEEE/RSJ International Conference on Intelligent Robots and Systems; 11/2013
Magnetic driven wireless capsule endoscopy (WCE) represents one of the last achievements in the ... more Magnetic driven wireless capsule endoscopy (WCE) represents one of the last achievements in the research of minimally invasive tools for gastrointestinal tract (GI) diagnosis. Recently, capsule localization methodologies have been employed to enable system autonomy maintaining a magnetic link with the device and managing interaction forces with GI tissues. To achieve these objectives, the locomotion platforms exploit automatic motion in some degrees of freedom and unsupervised contact with the external patient abdomen can occur. In this paper safety issues are faced; in particular a safety system, able to monitor pressure with patient abdomen, has been designed, characterized, and integrated with a magnetic driven WCE locomotion platform. New technologies, such as smart textiles, have been employed as sensible element.
A Three-Axial Body Force Sensor for Flexible Manipulators
This paper introduces an optical based three axis
force sensor which can be integrated with the ... more This paper introduces an optical based three axis
force sensor which can be integrated with the robot arm of the
EU project STIFF-FLOP (STIFFness controllable Flexible and
Learnable Manipulator for Surgical Operations) in order to
measure applied external forces. The structure of the
STIFF-FLOP arm is free of metal components and electric
circuits and, hence, is inherently safe near patients during
surgical operations. In addition, this feature makes the
performance of this sensing system immune against strong
magnetic fields inside magnetic resonance (MR) imaging
scanners. The hollow structure of the sensor allows the
implementation of distributed actuation and sensing along the
body of the manipulator. In this paper, we describe the design
and calibration procedure of the proposed three axis
optics-based force sensor. The experimental results confirm the
effectiveness of our optical sensing approach and its
applicability to determine the force and momentum components
during the physical interaction of the robot arm with its
environment.
Self-reconfigurable modular robots have been studied worldwide mainly for autonomous exploration ... more Self-reconfigurable modular robots have been studied worldwide mainly for autonomous exploration in unstructured environments. In previous studies, robotic modules were designed to be functional only as a part of an assembled structure, and thus the exploration capability was limited. Symbiotic multi-robot organisms have been newly proposed to design robotic modules as large-scale swarms of robots that can physically dock with each other and symbiotically share energy and computational resources within a single “artificial-life-form”. In this paper, a novel robotic module named Scout Robot, which is one of the three robotic platforms designed for the multi-robot organisms, is presented. The Scout robot is an autonomous miniature robot and equipped with many onboard sensors and a locomotion capability. It can move autonomously on rough terrains to explore the surroundings and interact with the other robots. The Scout robot is also equipped with 2 DoFs of actuation and shares the same docking design with the other robotic platforms, and thus can be a part of an assembled organism. In the experiments, the image-guided locomotion of a Scout robot and the multimodal locomotion of assembled robots were demonstrated.
Homogeneity and heterogeneity represent a well-known trade-off in the design of modular robot sys... more Homogeneity and heterogeneity represent a well-known trade-off in the design of modular robot systems. This work addresses the heterogeneity concept, its rationales, design choices and performance evaluation. We introduce challenges for self-reconfigurable systems, show advances of mechatronic and software design of heterogeneous platforms and discuss experiments, which intend to demonstrate usability and performance of this system.
The design of a pneumatically actuated silicone module, resembling soft tissue, with three pneuma... more The design of a pneumatically actuated silicone module, resembling soft tissue, with three pneumatic chambers is considered and optimized in this study with the aim of using it in a soft robot arm for robotic surgery applications. Three types of silicone materials, Ecoflex 0030 and 0050 and Dragonskin 0030, have been investigated, and a constitutive model has been derived for each of them. Design optimization of the silicone module was based on finite element analysis (FEA) that was validated against experimental data of one-degree bending under one-channel actuation. This was followed by FEA parametric studies for module design opti-mization to minimize the ballooning effect in one-degree bending as well as reduce the actuation pressure. Modules made from Ecoflex 0030 and Ecoflex 0050 exhibited the same bending shape in FEA, but about three times higher actuation pressure was required for the harder Ecoflex 0050. Design parameters under investi-gation in the parametric FEA studies ...
Soft robotics for medical, endoscopic applications requires a dexterous and compliant mechanism t... more Soft robotics for medical, endoscopic applications requires a dexterous and compliant mechanism to increase accessibility and decrease patient injury. However, soft structures do not offer the level of image and platform stability provided by rigid structures. Thus, a variable stiffness mechanism is an ideal solution to reconcile the two requirements of compliance and stability; the mechanism explored here is granular jamming. Granular jamming is a phenomenon where particulate matter within a membrane can transition from a fluid-like to a solid-like state, based on the level of applied vacuum pressure. In the solid-like jammed state, the conventional assumption is made that granule-granule contacts dominantly contribute to the system's stiffness. Thus, many works have evaluated the effects of different granule types by experimentally varying the sizes, shapes, and material properties of the particles. However, the role of the membrane in determining the possible range of stiffn...
This paper presents the design of a single module composing a modular soft variable stiffness man... more This paper presents the design of a single module composing a modular soft variable stiffness manipulator for minimal access surgery. The module exploits flexible fluidic actuation for obtaining multi directional bending and elongation capabilities. A novel flexible crimped braided sheath is introduced in order to increase the performances of the flexible actuator. Granular jamming based stiffening mechanism is used to tune the stiffness of the module. The fabrication of the module is described and the performances in terms of bending, elongation and stiffening are reported. Keywords— Surgical manipulator; soft manipulator; variable stiffness; minimally invasive surgery; flexible fluidic actuator; granular jamming; crimped braided structure
Soft robots provide significant advantages over their rigid counterparts. These compliant, dexter... more Soft robots provide significant advantages over their rigid counterparts. These compliant, dexterous devices can navigate delicate environments with ease without damage to themselves or their surroundings. With many degrees of freedom, a single soft robotic actuator can achieve configurations that would be very challenging to obtain when using a rigid linkage. Because of these qualities, soft robots are well suited for human interaction. While there are many types of soft robot actuation, the most common type is fluidic actuation, where a pressurized fluid is used to inflate the device, causing bending or some other deformation. This affords advantages with regards to size, ease of manufacturing, and power delivery, but can pose issues when it comes to controlling the robot. Any device capable of complex tasks such as navigation requires multiple actuators working together. Traditionally, these have each required their own mechanism outside of the robot to control the pressure withi...
The STIFF-FLOP robotic arm is a cylindrical structure made from soft silicone rubber materials en... more The STIFF-FLOP robotic arm is a cylindrical structure made from soft silicone rubber materials encasing pneumatic actuation chambers. Its material properties and structure allows for the shape, and therefore the pose of the arm, to be dictated by the actuation system as well as by the surfaces with which it is interacting. Although this softness and flexibility makes it inherently safe for many medical and industrial applications, such as keyhole surgery, it comes at the expense of complicating sensing and position control. This chapter presents the main challenges for the development of a pose sensor for soft robotic arms and the STIFF-FLOP approach to tackle them.
INTRODUCTION Robotic surgery is nowadays common in clinical practice, thanks to the spread of the... more INTRODUCTION Robotic surgery is nowadays common in clinical practice, thanks to the spread of the Intuitive Surgical’s Da Vinci platform [1]. The next generation of surgical robots should still guarantee the same dexterity and performances, while reducing access trauma. A promising approach in this direction is represented by robotic platforms specifically developed for laparoendoscopic single site (LESS) surgery [2-4]. Actuation for the several degrees of freedom (DoFs) may be external, by means of cables [2], internal, using on-board motors [3], or hybrid [4]. In any case, the mechanical continuity of the kinematic chain constraints the workspace to the insertion point proximities. Having the single components of the platform, i.e. at least 2 manipulators and one camera, magnetically linked across the abdominal wall as in [5] would greatly enhance both freedom of operation and triangulation. On the other hand, relying just on on-board motor actuation, as in [6], results in limited...
Millimeter-sized electrostatic film actuators, inspired by the efficient spatial arrangement of i... more Millimeter-sized electrostatic film actuators, inspired by the efficient spatial arrangement of insect muscles, achieve a muscle-like power density (61 W kg−1) and enable robotic applications in which agility is needed in confined spaces. Like biological muscles, these actuators incorporate a hierarchical structure, in this case building from electrodes to arrays to laminates, and are composed primarily of flexible materials. So comprised, these actuators can be designed for a wide range of manipulation and locomotion tasks, similar to natural muscle, while being robust and compact. A typical actuator can achieve 85 mN of force with a 15 mm stroke, with a size of [Formula: see text] mm3 and mass of 92 mg. Two millimeter-sized robots, an ultra-thin earthworm-inspired robot and an intestinal-muscle-inspired endoscopic tool for tissue resection, demonstrate the utility of these actuators. The earthworm robot undertakes inspection tasks: the navigation of a 5 mm channel and a 19 mm squa...
Recent advances in medical robotics have initiated a transition from rigid serial manipulators to... more Recent advances in medical robotics have initiated a transition from rigid serial manipulators to flexible or continuum robots capable of navigating to confined anatomy within the body. A desire for further procedure minimization is a key accelerator for the development of these flexible systems where the end goal is to provide access to the previously inaccessible anatomical workspaces and enable new minimally invasive surgical (MIS) procedures. While sophisticated navigation and control capabilities have been demonstrated for such systems, existing manufacturing approaches have limited the capabilities of millimeter-scale end-effectors for these flexible systems to date and, to achieve next generation highly functional end-effectors for surgical robots, advanced manufacturing approaches are required. We address this challenge by utilizing a disruptive 2D layer-by-layer precision fabrication process (inspired by printed circuit board manufacturing) that can create functional 3D mec...
Volume 5A: 39th Mechanisms and Robotics Conference, 2015
Recently, there has been a growing interest in moving away from traditional rigid exoskeletons to... more Recently, there has been a growing interest in moving away from traditional rigid exoskeletons towards soft exosuits that can provide a variety of advantages including a reduction in both the weight carried by the wearer and the inertia experienced as the wearer flexes and extends their joints. These advantages are achieved by using structured functional textiles in combination with a flexible actuation scheme that enables assistive torques to be applied to the biological joints. Understanding the human-suit interface in these systems is important, as one of the key challenges with this approach is applying force to the human body in a manner that is safe, comfortable, and effective. This paper outlines a methodology for characterizing the structured functional textile of soft exosuits and then uses that methodology to evaluate several factors that lead to different suit-human series stiffnesses and pressure distributions over the body. These factors include the size of the force di...
Fluidic soft robots bring a high degree of dexterity and adaptability to robotics problems requir... more Fluidic soft robots bring a high degree of dexterity and adaptability to robotics problems requiring safe interactions with complex structures. While they are low cost and easy to manufacture, they are difficult to control due to their typical reliance on external pressure sources that become bulky as more degrees of freedom are introduced to the robot. Various techniques from microfluidics and fluid logic are used to introduce valves into soft robots to increase their autonomy, although this has frequently introduced unwanted rigidity. Herein, a magnetorheological (MR) fluid valve that uses magnetic fields to control the pressure within a continuous‐flow fluidic actuator is introduced. A predictive model for the pressure drop in such a flow is presented and validated experimentally. Guidelines for the design of single‐ and multiactuator systems with a single inlet and outlet are presented. The introduction of actuation methods that simplify fluidic control via the application of magnetic fields leads to robots capable of increased autonomy in a scalable and compliant format.
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Soft Robotics by Tommaso Ranzani
development of a modular soft manipulator for
minimally invasive surgery, which equals the high
dexterity of classic hyper redundant continuum, but
rigid, robots resulting in safer potential interaction
with internal organs. The manipulator relies on the use
of a soft flexible fluidic actuator in each of its modules,
which can be wireless controlled by means of an
embedded fluidic control unit. This actuation unit is
equipped with three miniaturized latching valves, a
wireless microcontroller board, and a specifically
designed fluidic distributor integrated into the elastomeric
material that the module is made of. FEM
simulations and experimental tests verified the reliability
of the distributor in acting as a piping system
inside each module. The mobility of the fully
integrated soft module was evaluated in terms of
static performances and covered workspace. The
module’s dynamic model during one-chamber motion
was estimated from the parameter estimation analysis.
The characterization of the single module behaviour is
intended as first step to ease the future high level
control of the multi-modular architecture.
development of a modular soft manipulator for
minimally invasive surgery, which equals the high
dexterity of classic hyper redundant continuum, but
rigid, robots resulting in safer potential interaction
with internal organs. The manipulator relies on the use
of a soft flexible fluidic actuator in each of its modules,
which can be wireless controlled by means of an
embedded fluidic control unit. This actuation unit is
equipped with three miniaturized latching valves, a
wireless microcontroller board, and a specifically
designed fluidic distributor integrated into the elastomeric
material that the module is made of. FEM
simulations and experimental tests verified the reliability
of the distributor in acting as a piping system
inside each module. The mobility of the fully
integrated soft module was evaluated in terms of
static performances and covered workspace. The
module’s dynamic model during one-chamber motion
was estimated from the parameter estimation analysis.
The characterization of the single module behaviour is
intended as first step to ease the future high level
control of the multi-modular architecture.
(Natural Orifice Translumenal Endoscopic Surgery) robotic
approaches to enable scarless surgical procedures. Despite of
the variegated devices proposed, they still have several
limitations. In this work, we propose a surgical platform
composed of specialized modules, in order to provide the
overall system with adequate stability, dexterity and force
generation. The concept behind the platform, the main modules
and their performance are described to highlight the system
potential to outperform current NOTES procedures.
force sensor which can be integrated with the robot arm of the
EU project STIFF-FLOP (STIFFness controllable Flexible and
Learnable Manipulator for Surgical Operations) in order to
measure applied external forces. The structure of the
STIFF-FLOP arm is free of metal components and electric
circuits and, hence, is inherently safe near patients during
surgical operations. In addition, this feature makes the
performance of this sensing system immune against strong
magnetic fields inside magnetic resonance (MR) imaging
scanners. The hollow structure of the sensor allows the
implementation of distributed actuation and sensing along the
body of the manipulator. In this paper, we describe the design
and calibration procedure of the proposed three axis
optics-based force sensor. The experimental results confirm the
effectiveness of our optical sensing approach and its
applicability to determine the force and momentum components
during the physical interaction of the robot arm with its
environment.