The primary issue in bilateral teleportation setups is the existence of communication delays, which can destabilize the system. We are addressing this challenge in the case of a bilateral leader–follower surgical setup, where the surgeon uses a haptic device as the leader robot to manipulate the surgical instrument held by a general-purpose manipulator, the follower robot. The follower robot is equipped with an elongated tool that through a small incision passes inside the patient's body, where sensitive structures may exist. These structures may include organs, arteries, or veins that require protection during surgery. To address this challenge, we propose a bilateral control framework that is proven to maintain passivity, ensure bounded tracking errors between the leader and follower robots, and impose remote center of motion and spatial constraints related with the sensitive structures, all in the presence of constant and variable communication delays. Experimental results in a virtual intraoperative environment, using a point cloud of a kidney and its surrounding vessels, demonstrate the effectiveness of our control scheme under various communication delay scenarios.

In robotic assisted surgeries, surgical tools are inserted into the human body via an incision point in the abdominal wall, which is imposed as a remote center of motion (RCM). The selection of the incision's point location in the human body is critical for the success of the surgical procedure. In this paper, we propose a simulation tool for finding the optimal incision point location, which can be utilized by the surgeon during the preoperative stage. The surgeon can plan the path/region of intervention as well as sensitive regions which should be protected from unintentional damage by the surgical tool on the preoperative images of internal organs. A target admittance model that enforces a candidate incision as a RCM is utilized in the simulation enhanced by a term for following the planned path. We propose a cost evaluation function taking into account metrics involving the distance of the tool from sensitive areas, the tool links maximum pressure on tumors and the robot's dexterity measure. The example of a tumor resection task is used with the simulation tool to demonstrate its use in finding the incision points that ensures minimal intraoperative risks and accurate task execution.

We consider the problem of controlling a bilateral leader-follower robotic surgical set-up to allow kinesthetic haptic feedback to the user when the instrument approaches a forbidden area like sensitive organs arteries or veins that should be protected from injuries during surgery. The leader is a haptic device while the follower is a general purpose manipulator holding an elongated tool with an articulated instrument that should be manipulated through an entry port. We propose a control framework that is proved passive, incorporating a target admittance model for the follower that is designed in a way to impose a remote center of motion (RCM) while being subject to repulsive forces generated by properly designed artificial potentials associated with forbidden areas. Simulation and experimental results utilizing a virtual intraoperative environment provided as a point cloud of a kidney and its surrounding vessels characterized as forbidden areas, validate and demonstrate the performance of the proposed control scheme.

In this work, the problem of cooperative human-robot manipulation of an object with large inertia is addressed, considering the availability of a kinematically controlled industrial robot. In particular, a variable admittance control scheme is proposed, where the damping is adjusted based on the power transmitted from the human to the robot, with the aim of minimizing the energy injected by the human while also allowing her/him to have control over the task. The proposed approach is evaluated via a human-in-the-loop setup and compared to a generic variable damping state-of-the-art method. The proposed approach is shown to achieve significant reduction of the human’s effort and minimization of unintended overshoots and oscillations, which may deteriorate the user’s feeling of control over the task.

In this article, a passive physical human-robot interaction (pHRI) controller is proposed to enhance pHRI performance in terms of precision, cognitive load, and user effort, in cases partial knowledge of the task is available. Partial knowledge refers to a subspace of SE(3) determined by the desired task, generally mixing both position and orientation variables, and is mathematically approximated by parametric expressions. The proposed scheme, which utilizes the notion of virtual constraints and the prescribed performance control methodology, is proved to be passive with respect to the interaction force, while guaranteeing constraint satisfaction in all cases. The control scheme is experimentally validated and compared with a dissipative control scheme utilizing a KUKA LWR4+ robot in a master-slave task; experiments also include an application to a robotic assembly case.

In this work, a passive physical human-robot interaction (pHRI) controller is proposed to intraoperatively ensure that sensitive tissues will not be damaged by the robot's tool. The proposed scheme uses the point cloud of the restricted region's surface as constraint definition and Artificial Potential fields for constraint enforcement. The controller is proven to be passive with respect to the interaction force and to guarantee constraint satisfaction in all cases. The proposed methodology is experimentally validated by the kinesthetic guidance of a KUKA LWR4+ robot's end-effector driving a virtual slave KUKA in the vicinity of a 3D point-cloud of a kidney and its adjacent vessels.