Juan Sandoval

A predictive control approach and interactive GUI to enhance distal environment rendering during robotized tele-echography: Interactive platform for robotized telechography

Performing a robotized telemedicine act via specific networks brings forth two issues. One is transparency in order to enable the operator, e.g. the medical ultrasound specialist, to safely and accurately perform bilateral tele-operation tasks despite the long time delays inherent to the communication link. To counter these effects, two strategies are combined to improve, at the operator site, the rendering of the interactions between the remote robotic systems with its environment (i.e. the patient), and the control of the robots orientation. The first approach is the development of a new control architecture based on an internal model providing an anticipated value of the distant environment stiffness; it is complemented with a graphic user interface (GUI) which provides the expert with the real-time relative position of the haptic probe with the robots end effector for a better tele-operated control. These combined strategies provide the expert with an improved interactive tool for a tele-diagnosis.

Safety Performance of a Variable Stiffness Actuator for Collaborative Robots

Integration of active compliant joints in a robotic system contributes to enhance safety in physical human-robot interactions. In this paper we study the behavior of a variable stiffness actuator -V2SOM-, proposed in the context of the SISCob project. We describe the working principle and design of the proposed system. Furthermore, the dynamic modeling, including its nonlinear stiffness law, is presented. A preliminary study is conducted to evaluate the safety performance of a collaborative robot using the proposed mechanism. Thus, a dynamic simulator has been developed to integrate the compliant behavior of V2SOM in two joints of a Kuka iiwa robot. In order to evaluate the safety performance of the system, some following-trajectory tasks are executed in a planar workspace whereas unexpected collisions are produced with an unknown environment. The results presented in this paper show the effectiveness of V2SOM, enhancing the safety performance of the robot.

Kinematic Design of a Lighting Robotic Arm for Operating Room

This paper deals on the design method applied to create a new useful robot for a lighting operating room. We present the specifications for this particular medical application, the proposed kinematic solutions as well as the topological and dimensional syntheses performed to choice the optimal solution. The work presented in this paper was conducted with a closely industrial collaboration, and a patent application of the chosen kinematic solution has been filed.

Improved dynamic formulation for decoupled cartesian admittance control and RCM constraint

In this paper, we present a dynamically consistent control approach for manipulators with Cartesian Admittance Control (CAC) while guaranteeing a Remote Center of Motion (RCM) constraint. The dynamically consistent extended formulation was used in order to achieve a dynamically decoupled redundancy resolution, while a null-motion feedback was implemented that improves the tracking of the null-motion. Minimally Invasive Surgery (MIS) procedures are proposed as applications of the control approach formulated in this paper. The effectiveness of the proposed control approach was verified in simulation by using the Kuka LBR 7 iiwa R800 robot arm.

An Anticipative Control Approach and Interactive GUI to Enhance the Rendering of the Distal Robot Interaction with its Environment during Robotized Tele-Echography: Interactive Platform for Robotized Tele-Echography

Performing a robotized telemedicine act via specific networks brings forth the issue of transparency in order to enable the operator, e.g. the medical ultrasound specialist, to safely and accurately perform bilateral tele-operation tasks despite the long time delays inherent to the communication link. To counter these effects, two strategies are combined to improve, at the operator site, the rendering of the interactions between the remote robotic systems with its environment i.e. the patient, and the control of the robots orientation at the operator site. The first approach is the development of a new control architecture based on an internal model providing an anticipated value of the distant environment stiffness; it is complemented with a graphic user interface GUI which provides the expert with the real-time relative position of the haptic probe with the robots end effector for better tele-operated control. These combined strategies provide the expert with an improved interactive tool for tele-diagnosis.

Towards a Safe Physical Human-Robot Interaction for Tele-Operated System: Application to Doppler Sonography

The use of variable stiffness actuators in robots allows to enhance the human safety criteria when both human and robot coexist in a shared workspace. We study the behavior of V2SOM, a joint variable stiffness mechanism developed by Pprime Institute, when the mechanism is adapted in the joints of a multi-DoF robot. We compare the impact forces produced by a rigid-body and the joint-flexible robot, through the dynamic model of a 7-DoF robot. We propose the robot-assisted Doppler echography as an example of application, where patient safety must be guaranteed by effectively limiting the force applied by the robot over the patient. For this purpose, we define a cartesian control approach allowing to control the displacements of the ultrasound probe carried by the robot’s end-effector. Simulation results showed the effectiveness of using the V2SOM in a multi-DoF robot, in terms of human safety.

Collaborative framework for robot-assisted minimally invasive surgery using a 7-DoF anthropomorphic robot

Abstract In this paper, we propose a control framework for robot-assisted minimally invasive general surgery (RA-MIS) for physical human–robot collaboration using a redundant 7-DoF serial robot. When a redundant manipulator is used in RA-MIS, the control system implemented must guarantee that the surgical tool always goes through the trocar, i.e. the medical instrument placed at the incision point on the patient’s body. In addition, the redundancy of the robot can be exploited to implement a physical human–robot collaborative strategy, allowing the medical staff and robot to work in a shared common workspace without affecting the performances of the surgical task, through a null-space compliance control strategy. However, classical null-space compliance laws are defined in joint coordinates, which have some limitations. First, an arbitrary desired joint configuration is rarely contained in the robot’s null-space, making the desired configuration unattainable. Moreover, the joint coordinates are not a direct representation of the robot’s null-space, which limits its exploitation. The control framework proposed in this paper is performed at the torque level. A manual motion mode is used to calibrate the trocar position before executing the task. Then, a cartesian compliance control strategy is activated during execution of the surgical task, enabling the robot to autonomously execute the surgical task while the tool orientation is calculated with respect to the trocar position. Furthermore, in order to preserve the surgical task when desired or undesired contacts occur, the null-space of the main task, i.e. surgical task, is used to implement a compliant motion in the robot’s body. The compliance control approach is defined in the swivel coordinates, which effectively represent the null-space of the robot, in order to easily restrict the swivel angle motion based on joint limitations or on any other physical constraint existing in the operating room. Finally, we evaluate our control framework using a robotic system including the KUKA LWR 4 + robot, demonstrating the feasibility of the null-space compliance control approach while preserving the accuracy of the surgical task.

Design Process of a New Lighting Robotic Arm for Operating Room

In this paper, we present the design process followed to conceive a lighting robotic arm dedicated to operating rooms. During a surgical procedure, the use of a high quality lighting system is essential to the successful completion of the surgical task. Indeed, the intensity and incidence of the light projection must be controlled according to the surgeon needs. However, surgeons cannot directly manipulate the lighting dome by hand because of aseptic reasons. First of all, we present the medical specifications used to define the technological and robotic needs, provided from real experiments and observations in operating room. Then, a complete topological synthesis has been applied to choose the most adequate kinematic solution. A kinematic simulator, as well as a prototype, have been developed to validate the effectiveness of the selected solution. Finally, we propose the use of a dynamic analysis, based on a Newton-Euler algorithm, to correctly choose the joint actuators.