Efi Psomopoulou | University of Bristol (original) (raw)

Papers by Efi Psomopoulou

The thesis deals with the problem of grasping by robotic hands as well as the human-robot haptic ... more The thesis deals with the problem of grasping by robotic hands as well as the human-robot haptic interaction during object load transfer. A passivity-based stable grasping control law for unknown object weight is exploited and extended in order to be used in the design of two strategies for the safe and natural human-robot object load transfer which takes place in the direction of the gravity field. The controller is extended with respect to the desired grasping force and the object's mass that is allocated to the respective hand. The extension is based on human studies on the grasping and load forces that are developed by the giver and receiver. The first object load transfer strategy is initiated by the giver who linearly decreases its load and grip forces until the full release of the object’s load. It is assumed that the receiver estimates the load transfer successfully and adapts its grip forces accordingly to achieve an efficient object transfer, ie. the receiver is either...

Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ). Σχολή Πολυτεχνική. Τμήμα Ηλεκτρολόγων Μηχανικών και Μηχανικών Υπολογιστών. Τομέας Ηλεκτρονικής και Υπολογιστών. Εργαστήριο Αυτοματοποίησης και Ρομποτικής, 2017

IFMBE Proceedings, 2019

A desktop haptic device is used to teleoperate an industrial redundant and compliant robotic arm ... more A desktop haptic device is used to teleoperate an industrial redundant and compliant robotic arm with a surgical instrument mounted on its end-effector. The master and slave devices are coupled in a bilateral position-position architecture. Force feedback is provided by the master haptic device to the user, from the position of the slave's wrist. A surgical task (palpation) that involves force feedback is presented and tested in a user study with surgeons and non-medical participants. Results show that users easily discern between three different materials during palpation given minimal familiarisation time. Active constraint enforcement is also integrated with the system as a sensitive area around the palpation samples which the slave instrument is prohibited to enter.

IFMBE Proceedings, 2019

A novel master controller for robot-assisted minimally invasive surgery (RAMIS) is introduced and... more A novel master controller for robot-assisted minimally invasive surgery (RAMIS) is introduced and used to control a da Vinci En-doWrist instrument. The geometric model of the master mechanism and its mapping to the geometry of the EndoWrist tool are derived. Experimental results are conducted to open and close the jaws of an EndoWrist tool, and show that the developed mapping algorithm is accurate with a root mean square error of 0.7463 mm.

INTRODUCTION Robot-assisted minimally invasive surgery (RAMIS) has gained popularity in recent de... more INTRODUCTION Robot-assisted minimally invasive surgery (RAMIS) has gained popularity in recent decades through use of the da Vinci master-slave surgical system offering improved vision, precision and patient recovery time compared to traditional MIS [1]. However, certain shortcomings prevent RAMIS from fulfilling its maximum potential, including the lack of haptic feedback provided to the surgeon [2]. Attempts have been made to develop sensorised surgical instruments as a means to detect interaction forces during RAMIS and provide surgeons with haptic feedback. However, the size of force sensors and incision ports, the sterilisation of tools at high temperature as well as the disposable nature of surgical tools have so far prevented integration of endeffector/tissue force sensing in RAMIS [3, 4]. Force estimation algorithms that do not require sensing hardware at the operating site include visual estimation of the shaft deformation [5], modelling of surgical tooltissue interaction [...

IFMBE Proceedings, 2019

Robot Assisted Surgery is attracting increasing amount of attention as it offers numerous benefit... more Robot Assisted Surgery is attracting increasing amount of attention as it offers numerous benefits to patients as well as surgeons. Heart surgery requires a high level of precision and dexterity, in contrast to other surgical specialties. Robot assisted heart surgery is not as widely performed due to numerous reasons including a lack of appropriate and intuitive surgical interfaces to control minimally invasive surgical tools. In this paper, finger motion of the surgeon is analyzed during cardiac surgery tasks on an ex-vivo animal model with the purpose of designing a more intuitive master console. First, a custom finger tracking system is developed using IMU sensors, which is lightweight and comfortable enough to allow free movement of the surgeon’s fingers/hands while using instruments. The proposed system tracks finger joint angles and fingertip positions for three involved fingers (thumb, index, middle). Accuracy of the IMU sensors has been evaluated using an optical tracking sy...

2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2015

A human-inspired hand-over control strategy is proposed for the haptic interaction of two dual-fi... more A human-inspired hand-over control strategy is proposed for the haptic interaction of two dual-fingered hands for the planar case. It is based on a grasp controller for an unknown object which achieves, via fingertip rolling, a stable grasp and a real object mass estimation. Object load transfer is receiver initiated, follows human evidence and involves awareness of the other hand's state based solely on local proprioceptive measurements. Simulation results illustrate the proposed approach.

22nd Mediterranean Conference on Control and Automation, 2014

ABSTRACT A robot hand-over control scheme is proposed achieving human-like haptic interaction dur... more ABSTRACT A robot hand-over control scheme is proposed achieving human-like haptic interaction during object load transfer from a giver to a receiver hand for the planar case. It is assumed that the object has parallel surfaces and unknown mass. The giver initiates the hand-over process while the receiver estimates the transferred object mass adapting its grip force accordingly in a three stage process. The control laws are based on a dynamically stable grasp controller which is modified for the hand-over task. A stable load transfer is securely achieved as shown by the theoretical analysis and illustrated by the simulation results.

2012 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2012

ABSTRACT In this paper a simple tracking controller for a variable stiffness joint is proposed. S... more ABSTRACT In this paper a simple tracking controller for a variable stiffness joint is proposed. System dynamics is considered unknown. The controller guarantees link and stiffness motor position performance specifications that have been apriori set, utilizing full state feedback. Simulation results on the previously published CompAct-VSA joint validate the efficiency of the proposed control approach.

2014 IEEE International Conference on Robotics and Automation (ICRA), 2014

ABSTRACT This paper proposes a controller for the stable grasp of an arbitrary-shaped object on t... more ABSTRACT This paper proposes a controller for the stable grasp of an arbitrary-shaped object on the horizontal plane by two robotic fingers with rigid hemispherical fingertips. The controller stabilizes the grasp with optimal force angles and desired finger shaping determined through the choice of a control constant without requiring the utilization of any contact information regarding contact locations and contact angles or any estimates of them. Simulation results demonstrate the performance of the proposed controller and show its clear advantages with respect to other known control schemes.

IEEE Robotics and Automation Letters

Robot-assisted minimally invasive surgical procedures are long and complex involving large expert... more Robot-assisted minimally invasive surgical procedures are long and complex involving large expert teams that perform a plethora of tasks required for the successful completion of surgery. Since the mid-80s, robotic assistance involved a surgeon to teleoperate surgical tools providing no automation or autonomy in its performance. Enabling surgical robots for automation could provide more precision and speed while obviating the need for long surgical training to carry out unwieldy tasks. This paper considers one aspect of using robotic instruments to autonomously perform precision motion in robot-assisted laparoscopic surgery where robotic instruments go through trocars inserted through the patient’s skin. The experience shows that the elasticity of the skin causes displacements of the incision ports which can result in localization and motion errors, thus, creating inaccuracy in robot performance by moving the instrument in undesirable directions. The offline calibration that calcula...

IEEE Robotics and Automation Letters

Frontiers in Robotics and AI

A new algorithm is proposed to estimate the tool-tissue force interaction in robot-assisted minim... more A new algorithm is proposed to estimate the tool-tissue force interaction in robot-assisted minimally invasive surgery which does not require the use of external force sensing. The proposed method utilizes the current of the motors of the surgical instrument and neural network methods to estimate the force interaction. Offline and online testing is conducted to assess the feasibility of the developed algorithm. Results showed that the developed method has promise in allowing online estimation of tool-tissue force and could thus enable haptic feedback in robotic surgery to be provided.

Robotica

SUMMARY There is a large gap between reality and grasp models that are currently available becaus... more SUMMARY There is a large gap between reality and grasp models that are currently available because of the static analysis that characterizes these approaches. This work attempts to fill this need by proposing a control law that, starting from an initial contact state which does not necessarily correspond to an equilibrium, achieves dynamically a stable grasp and a relative finger orientation in the case of pinching an object with arbitrary shape via rolling soft fingertips. Controlling relative finger orientation may improve grasping force manipulability and allow the appropriate shaping of the composite object consisted of the distal links and the object, for facilitating subsequent tasks. The proposed controller utilizes only finger proprioceptive measurements and is not based on the system model. Simulation and experimental results demonstrate the performance of the proposed controller with objects of different shapes.

IEEE Transactions on Control Systems Technology, 2015

ABSTRACT This paper is concerned with the design of a state feedback control scheme for variable ... more ABSTRACT This paper is concerned with the design of a state feedback control scheme for variable stiffness actuated (VSA) robots, which guarantees prescribed performance of the tracking errors despite the low range of mechanical stiffness. The controller does not assume knowledge of the actual system dynamics nor does it utilize approximating structures (e.g., neural networks and fuzzy systems) to acquire such knowledge, leading to a low complexity design. Simulation studies, incorporating a model validated on data from an actual variable stiffness actuator (VSA) at a multi-degrees-of-freedom robot, are performed. Comparison with a gain scheduling solution reveals the superiority of the proposed scheme with respect to performance and robustness.

Robotica, 2017

There is a large gap between reality and grasp models that are currently available because of the... more There is a large gap between reality and grasp models that are currently available because of the static analysis that characterizes these approaches. This work attempts to fill this need by proposing a control law that, starting from an initial contact state which does not necessarily correspond to an equilibrium, achieves dynamically a stable grasp and a relative finger orientation in the case of pinching an object with arbitrary shape via rolling soft fingertips. Controlling relative finger orientation may improve grasping force manipulability and allow the appropriate shaping of the composite object consisted of the distal links and the object, for facilitating subsequent tasks. The proposed controller utilizes only finger proprioceptive measurements and is not based on the system model. Simulation and experimental results demonstrate the performance of the proposed controller with objects of different shapes.

IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

A human-inspired hand-over control strategy is proposed for the haptic interaction of two dual-fi... more A human-inspired hand-over control strategy is proposed for the haptic interaction of two dual-fingered hands for the planar case. It is based on a grasp controller for an unknown object which achieves, via fingertip rolling, a stable grasp and a real object mass estimation. Object load transfer is receiver initiated, follows human evidence and involves awareness of the other hand’s state based solely on local proprioceptive measurements. Simulation results illustrate the proposed approach.

This paper is concerned with the design of a state feedback control scheme for variable stiffness... more This paper is concerned with the design of a state feedback control scheme for variable stiffness actuated (VSA) robots, which guarantees prescribed performance of the tracking errors despite the low range of mechanical stiffness. The controller does not assume knowledge of the actual system dynamics nor does it utilize approximating structures (e.g., neural networks and fuzzy systems) to acquire such knowledge, leading to a low complexity design. Simulation studies, incorporating a model validated on data from an actual variable stiffness actuator (VSA) at a multi-degrees-of-freedom robot, are performed. Comparison with a gain scheduling solution reveals the superiority of the proposed scheme with respect to performance and robustness.

IFMBE Proceedings, 2019

2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2015

22nd Mediterranean Conference on Control and Automation, 2014

2012 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2012

2014 IEEE International Conference on Robotics and Automation (ICRA), 2014

IEEE Robotics and Automation Letters

Frontiers in Robotics and AI

Robotica

IEEE Transactions on Control Systems Technology, 2015

Robotica, 2017

IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

A human-inspired hand-over control strategy is proposed for the haptic interaction of two dual-fi... more A human-inspired hand-over control strategy is proposed for the haptic interaction of two dual-fingered hands for the planar case. It is based on a grasp controller for an unknown object which achieves, via fingertip rolling, a stable grasp and a real object mass estimation. Object load transfer is receiver initiated, follows human evidence and involves awareness of the other hand’s state based solely on local proprioceptive measurements. Simulation results illustrate the proposed approach.