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Endoscopic surgery has recently been adopted in various surgical operations. Forceps stuck through trocars into the abdominal or chest cavity, dissects and grasps internal organs. Due to their fixed shapes, the current forceps limit the skill of surgeons. We have worked on the development of active forceps adoping shape-memory-alloy pipes and coaxicially assembling them. In this paper, we show several...
This paper describes experiments using a new concept in robot surgery; that of a robot with a force control handle moved by the Surgeon. The surgeon back-drives the robot under servo assistance, whilst feeling the force from a rotating cutter during surgery, for example, in total knee replacement. Thus, when machining the knee bones to take a prosthetic metal replacement, the surgeon can use his inherent...
In this paper, two different control technics for SMA actuators are proposed: a position control and a temperature one. The position controller is based on a two stage (P and PI) structure. The temperature controller uses a PID with a lag compensator in the feedback loop. Both of these simple technics have been designed for integration in micro-actuators. They have been experimented and have shown...
This paper presents the design of an optimal nonlinear position tracking controller for an experimental two-link flexible joint robot manipulator. The controller is designed based on the concept of exact feedback linearization and LQG/LTR control design techniques. The proposed control approach reduces the number of required measurement sensors and takes into account the effects of measurement noises...
This paper deals with the joint position control of a robotic finger designed to test the force feedback performance of an hand controller. The robotic finger is actuated with 3 DC motors located on the base link, which drive the joints by means of bidirectional cable transmissions. The focus of the work is on the analisys of the influence of the elastic cable transmission on the robot dynamics and...
Modelling and experimental identification of a hydraulic servoactuator system is presented. The development of the model is important for further understanding the system and for developing a robust force controller. System parameters are identified using the elbow joint of the SARCOS slave experimental hydraulic manipulator. Experimental work is central to achieving the modelling objectives. Physical...
This paper propose an adaptive visual servoing method consisting of an on-line estimator of the robot/image Jacobian matrix and a feedback/feedforward controller for uncalibrated camera-manipulator systems. The estimator does not need a priori knowledge on the kinematic structure nor on parameters of the camera-manipulator system. The controller consists of feedforward and feedback terms to make the...
Access to restricted spaces underwater requires a small unencumbered camera. A low cost solution has been envisaged. It consists of an hermetic capsule enclosing the camera and lights, joined to the host by an umbilical. Along the umbilical go six water carrying ducts. Three of them end at backwards pointing nozzles located at the capsule body. The jets of water flowing from the nozzles are controlled...
The stabilization to a desired pose of a nonholonomic mobile robot carrying a manipulator arm, based on sensory data provided by a camera mounted on the end-effector of the arm, is considered. Instances of this problem occur in practice during docking or parallel parking maneuvers of such vehicles. The visual data obtained as the camera tracks a target of known geometry are used to implement a continuous...
Robotic applications are real-time dynamical systems which intimately combine different components ranging from high-level decision making and discrete-event controllers to low-level feedback loops. Tightly coupling the two last components and considering them in a formal framework permitted, in a centralized approach, both crucial properties to be proved and efficient implementation. We examine this...
This paper describes a set of tools developed at our laboratory that provide a reliable set-up for conducting bio-inspired experiments with real robots. We focus on the hardware tools needed to monitor team performances as well as those to achieve collective adaptive behaviours. We propose concrete solutions to some of the main problems in collective robotics. The four main results we derive are:...
This paper describes experiments in cooperation using autonomous mobile robots to perform a cleaning task. The robots have heterogeneous capabilities and the task is designed so that cooperation is required. Each experiment increases the sophistication of the cooperation scheme to assess the effect on task performance. The experiments range from using emergent cooperation with no communication to...
Self-reconfigurable robots consist of a set of one or more identical autonomous modules that can adapt their shape and function to tasks. We describe a module that can function as a climbing robot, a manipulator, or a leg in a multi-legged walker. This module can make autonomous transitions between these states. We present the control algorithms that enable our robot to be a versatile navigator and...
A system to allow control of multiple mobile robot systems by a single human operator is proposed. The main feature of the system is that the unit of control is, not the individual robot, but the group of robots. This control paradigm is tested by creating a system that allows a human user to control 4 robots by means of a joystick. Experiments show that this kind of control is feasible and useful.
In this paper we are concerned with the problem of navigating an autonomous mobile robot, on an unknown indoor environment, without any external support or human intervention, from an initial location to a specified goal region. The parti-game self-learning approach is used, for simultaneous learning of a multiresolution world model, and learning a motion trajectory to the goal. The presented approach...
This paper investigates the problem of artificial perception related to manipulation tasks in robotics. The proposed approach is based on biological models of perception and sensory-motor co-ordination in humans and aims at devising anthropomorphic solutions to the problems of perception, learning and control in robotics. In particular, our approach involves the integration of different sensory...
We describe an integrated system for programming part-mating and contact tasks using simulation. A principle goal of this work is to make robotic programming easy and intuitive for non-trained users. Using simulation, an operator can specify part placement and contact motions by simply “putting things where they belong’, without resorting to textual descriptions. We describe the simulation system,...
This paper describes a general approach to learning and planning robot manipulation strategies. Here, the strategies are represented using a discrete-event dynamical systems model where each node corresponds to a state in the robot task environment that triggers certain action schemata and each arc corresponds to a plausible action that brings the task environment into a new state. With such a representation,...
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