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PURPOSE Research on surgical robotics demands systems for evaluating scientific approaches. Such systems can be divided into dedicated and versatile systems. Dedicated systems are designed for a single surgical task or technique, whereas versatile systems are designed to be expandable and useful in multiple surgical applications. Versatile systems are often(More)
The paper presents a new torque-controlled lightweight robot for medical procedures developed at the Institute of Robotics and Mechatronics of the German Aerospace Center. Based on the experiences in lightweight robotics and anthropomorphic robotic hands, a small robot arm with 7 axis and torque-controlled joints tailored to surgical procedures has been(More)
This paper presents a novel system for accurate placement of pedicle screws. The system consists of a new light-weight (<10 kg), kinematically redundant, and fully torque controlled robot. Additionally, the pose of the robot tool-center point is tracked by an optical navigation system, serving as an external reference source. Therefore, it is possible to(More)
In this paper we introduce a friction observer for robots with joint torque sensing (in particular for the DLR medical robot) in order to increase the positioning accuracy and the performance of torque control. The observer output corresponds to the low-pass filtered friction torque. It is used for friction compensation in conjunction with a MIMO controller(More)
The paper describes the modeling and control of a robot with flexible joints (the DLR medical robot), which has strong mechanical couplings between pairs of joints realized with a differential gear-box. Because of this coupling, controllers developed before for the DLR light-weight robots cannot be directly applied. The previous control approach is extended(More)
In this paper we introduce an adaptive control scheme for robots with elastic joints (in particular for the DLR medical robot) in order to increase the positioning accuracy and the performance of control with respect to uncertainties of the parameters of the robot dynamics. In order to design control and analyze system stability a static friction model is(More)
— In this paper a control scheme is addressed to improve the tracking accuracy of flexible joint robots without replacing the structure of a MIMO state feedback controller which is used effectually with the DLR medical robots. By using the desired position, the new desired link torque, as well as their derivatives the effects of nonlinear dynamics are(More)