The strength of a haptic display may be assessed from its range of stable impedances. This paper presents a novel passive haptic display (PARM) capable of simulating a broad range of impedances. It comprises a passive constraint that can simulate both uninhibited motion through free-space and collision into a rigid obstacle. In free-space, the user feels the natural impedance of the end-effector without the added inertia and friction from a transmission or actuator. In a collision with a rigid object, haptic stiffness can be much greater than a traditional impedance haptic display. An experimental study with a 2 DoF planar manipulator illustrates the minimum and maximum impedances that are attainable for this haptic display. The inertial mass and friction in free-space are less than 0.2 kg and 12.3 Ns/m, and the stiffness against a haptic boundary is 465 N/mm. In addition, collision with a haptic object produces a more authentic experience, since there are naturally-occurring high frequency oscillations that result from the physical collision between two objects. This novel haptic display has both the minimum impedance benefits of impedance haptic displays and the maximum impedance benefits of admittance haptic displays.

Remote systems are essential for reducing risk to human workers from hazardous radiation and difficult work environments, while improving productivity and reducing costs. The major drawback of currently available remote manipulator systems is that teleoperation is slow and imprecise. The presented work focuses on enhancing remote operation of tools for D&D tasks by introducing teleautonomy and telecollaboration. In teleautonomy, the robot performs a given task autonomously, while the human operator intervenes in the process as a supervisor. In telecollaboration, the human operator is passively constrained by a virtual fixture, but is responsible for the motion. This work, sponsored by the US Department of Energy (DOE) Environmental Management Science Program (EMSP), builds on a reactive, agent-based control architecture and robot control technology.

There have been many innovations introduced in securing tissues, but suturing with secure knots remains the most popular and cost effective method. However, knot tying demands higher level of skill on the surgeon, especially in the minimally invasive context. This paper presents the analytical and experimental results of automatic knot tying using an inhouse surgical robot with emphasis on the placement of the knot and tension regulation. The problem is decomposed to two parts: knot placement and knot tension control. The knot sliding condition is first obtained based on a simplified model of half knotted suture, and motion trajectories for the robots are proposed to minimize tearing trauma of the tissue while properly place the knot. The second half the paper considers the automatic tension regulation in the knot, which is usually difficult for the surgeon to achieve accurately. By using a cost effective means for tension measurement and applying the explicit force control algorithm with active damping, we are able to achieve stable and robust tension regulation. Experimental results are presented to demonstrate efficacy of the proposed algorithm.

This paper presents a new surgical robotic system called EndoBot for assisting surgeons in performing minimally invasive surgery (MIS). The EndoBot is designed for collaborative operation between the surgeon and the robot. The demand on the surgeon is higher during suturing task which is the primary tissue approximation method and has been known as one of the most difficult tasks in MIS. Our work is the first effort in autonomous robotic suturing for MIS. In this paper, we show the motion controller design for autonomous and shared control mode and discuss autonomous robotic-suturing algorithms.