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PubMed2005

Using sensor habituation in mobile robots to reduce oscillatory movements in narrow corridors.

Habituation is a form of nonassociative learning observed in a variety of species of animals. Arguably, it is the simplest form of learning. Nonetheless, the ability to habituate to certain stimuli implies plastic neural systems and adaptive behaviors. This paper describes how computational models of habituation can be applied to real robots. In particular, we discuss the problem of the oscillatory movements observed when a Khepera robot navigates through narrow hallways using a biologically inspired neurocontroller. Results show that habituation to the proximity of the walls can lead to smoother navigation. Habituation to sensory stimulation to the sides of the robot does not interfere with the robot's ability to turn at dead ends and to avoid obstacles outside the hallway. This paper shows that simple biological mechanisms of learning can be adapted to achieve better performance in real mobile robots.

Algorithms↗

PubMed2002

Development of a robotic device for facilitating learning by children who have severe disabilities.

This paper presents technical aspects of a robot manipulator developed to facilitate learning by young children who are generally unable to grasp objects or speak. The severity of these physical disabilities also limits assessment of their cognitive and language skills and abilities. The CRS robot manipulator was adapted for use by children who have disabilities. Our emphasis is on the technical control aspects of the development of an interface and communication environment between the child and the robot arm. The system is designed so that each child has user control and control procedures that are individually adapted. Control interfaces include large push buttons, keyboards, laser pointer, and head-controlled switches. Preliminary results have shown that young children who have severe disabilities can use the robotic arm system to complete functional play-related tasks. Developed software allows the child to accomplish a series of multistep tasks by activating one or more single switches. Through a single switch press the child can replay a series of preprogrammed movements that have a development sequence. Children using this system engaged in three-step sequential activities and were highly responsive to the robotic tasks. This was in marked contrast to other interventions using toys and computer games.

Activities of Daily Living↗

PubMed2004

A new mobile robot control approach via fusion of control signals.

This paper proposes an alternative approach to address the problem of coordinating behaviors in mobile robot navigation: fusion of control signals. Such approach is based on a set of two decentralized information filters, which accomplish the data fusion involved. Besides these two fusion engines, control architectures designed according to this approach also embed a set of different controllers that generate reference signals for the robot linear and angular speeds. Such signals are delivered to the two decentralized information filters, which estimate suitable overall reference signals for the robot linear and angular speeds, respectively. Thus, the background for designing such control architectures is provided by the nonlinear systems theory, which makes this approach different from any other yet proposed. This background also allows checking control architectures designed according to the proposed approach for stability. Such analysis is carried out in the paper, and shows that the robot always reaches its final destination, in spite of either obstacles along its path or the environment layout. As an example, a control architecture is designed to guide a mobile robot in an experiment, whose results allows checking the good performance of the control architecture and validating the design approach proposed as well.

Algorithms↗

PubMed2004

Mental imagery for a conversational robot.

To build robots that engage in fluid face-to-face spoken conversations with people, robots must have ways to connect what they say to what they see. A critical aspect of how language connects to vision is that language encodes points of view. The meaning of my left and your left differs due to an implied shift of visual perspective. The connection of language to vision also relies on object permanence. We can talk about things that are not in view. For a robot to participate in situated spoken dialog, it must have the capacity to imagine shifts of perspective, and it must maintain object permanence. We present a set of representations and procedures that enable a robotic manipulator to maintain a "mental model" of its physical environment by coupling active vision to physical simulation. Within this model, "imagined" views can be generated from arbitrary perspectives, providing the basis for situated language comprehension and production. An initial application of mental imagery for spatial language understanding for an interactive robot is described.

Algorithms↗

PubMed2004

Development of a biomimetic robotic fish and its control algorithm.

This paper is concerned with the design of a robotic fish and its motion control algorithms. A radio-controlled, four-link biomimetic robotic fish is developed using a flexible posterior body and an oscillating foil as a propeller. The swimming speed of the robotic fish is adjusted by modulating joint's oscillating frequency, and its orientation is tuned by different joint's deflections. Since the motion control of a robotic fish involves both hydrodynamics of the fluid environment and dynamics of the robot, it is very difficult to establish a precise mathematical model employing purely analytical methods. Therefore, the fish's motion control task is decomposed into two control systems. The online speed control implements a hybrid control strategy and a proportional-integral-derivative (PID) control algorithm. The orientation control system is based on a fuzzy logic controller. In our experiments, a point-to-point (PTP) control algorithm is implemented and an overhead vision system is adopted to provide real-time visual feedback. The experimental results confirm the effectiveness of the proposed algorithms.

Algorithms↗

PubMed2004

A subsumptive, hierarchical, and distributed vision-based architecture for smart robotics.

We present a distributed vision-based architecture for smart robotics that is composed of multiple control loops, each with a specialized level of competence. Our architecture is subsumptive and hierarchical, in the sense that each control loop can add to the competence level of the loops below, and in the sense that the loops can present a coarse-to-fine gradation with respect to vision sensing. At the coarsest level, the processing of sensory information enables a robot to become aware of the approximate location of an object in its field of view. On the other hand, at the finest end, the processing of stereo information enables a robot to determine more precisely the position and orientation of an object in the coordinate frame of the robot. The processing in each module of the control loops is completely independent and it can be performed at its own rate. A control Arbitrator ranks the results of each loop according to certain confidence indices, which are derived solely from the sensory information. This architecture has clear advantages regarding overall performance of the system, which is not affected by the "slowest link," and regarding fault tolerance, since faults in one module does not affect the other modules. At this time we are able to demonstrate the utility of the architecture for stereoscopic visual servoing. The architecture has also been applied to mobile robot navigation and can easily be extended to tasks such as "assembly-on-the-fly."

Algorithms↗

PubMed2006

The balance between initial training and lifelong adaptation in evolving robot controllers.

A central aim of robotics research is to design robots that can perform in the real world; a real world that is often highly changeable in nature. An important challenge for researchers is therefore to produce robots that can improve their performance when the environment is stable, and adapt when the environment changes. This paper reports on experiments which show how evolutionary methods can provide lifelong adaptation for robots, and how this evolutionary process was embodied on the robot itself. A unique combination of training and lifelong adaptation are used, and this paper highlights the importance of training to this approach.

Adaptation, Physiological↗

PubMed2006

Dynamic coordination between robots: self-organized timing selection in a juggling-like ball-passing task.

This paper describes the hierarchical architecture for a rhythmic coordination between robots, which suits juggling-like tasks involving sensory-motor coordination. The authors' approach, which is interpreted as a "bidirectional weak coupling" to the environment, does not require either the environmental model or continuously monitoring the environment but can adapt the robots to a change in the environment, owing to the interaction between the robots and the environment at the ball contact. The proposed architecture contains two passive-control mechanisms, the "open-loop stable mechanism" and the "entrainment mechanism," that lead to the emergence of self-organized temporal structure for rhythmic movement. This dynamic pattern in the whole system realizes the stable coordinated motion between robots. The authors demonstrate two motion patterns between two robots passing two balls, and confirm the effectiveness of the approach.

Algorithms↗

PubMed2006

Robotic assisted thoracic surgery for resection of an esophageal cyst.

Many centers around the world are now developing robotic surgical programs. The benefit of robotics, particularly in those centers where there is already expertise with minimally invasive surgical techniques, is unclear. We present the case of a 58-year-old man presenting with an esophageal cyst. This was removed using a robotic assisted, VATS (video assisted thoracic surgery) approach. The technical details of the procedure are described. Additionally, a discussion of the relative merits of using a robotic rather than a standard minimally invasive approach is discussed. In a procedure such as the case described, the critical parts of the procedure are focused within a small operative field. We believe that the articulating instrumentation and the 3-dimensional magnified view provided by the robot offers significant advantages over a standard VATS approach.

Esophageal Cyst↗

PubMed2006

The proximal neurovascular plate and the tri-zonal neural architecture around the prostate gland: importance in the athermal robotic technique of nerve-sparing prostatectomy.

OBJECTIVE: To review the neural architecture around the prostate gland, as it is relevant for nerve-sparing robotic prostatectomy, including in particular the anatomy of the proximal neurovascular tissue, the neurovascular bundle (NVB), and accessory neural pathways (ANPs). MATERIALS AND METHODS: The aims of this study were achieved in collaboration between the Cornell Institute of Robotic Surgery, New York, NY, USA and the Institute of Urology at the University of Innsbruck, Austria. The broad steps were: (i) anatomical studies of 10 fresh and two fixed male cadavers; and (ii) collection of videotape and still image data from 200 men undergoing radical prostatectomy by the athermal robotic technique at the Cornell Institute. RESULTS: From a surgical standpoint there was a tri-zonal neural architecture including the proximal neurovascular plate (PNP), the predominant NVB (PNB) and ANPs. The PNP was a mean (range) of 5 (3-10) mm lateral to the seminal vesicles, was 3 (2-7) mm thick, 7 (5-25) mm wide and 9 (4-30) mm long. It was within 6 (4-15) mm of the bladder neck, 5 (2-7) mm of the endopelvic fascia and overlapped 5 (0-7) mm of the proximal prostate. The PNB varied in shape and size from the proximal to distal end, was thickest at the base and most variable near the apex. In eight of 12 cases, there was a medial extension behind the prostate, which converged medially at the apex in four cases. ANPs were noted within the layers of levator fascia and/or lateral pelvic fascia on the anterolateral aspect in five cases and in three on the posterior aspect of the prostate. In nine cadavers, the proximal third of the prostate was covered by the PNP where these ANPs were most prominent. The ANPs formed a plexus on the posterolateral aspect of the apex in four cases. CONCLUSION: We have created an anatomical map of neurovascular tissue relevant to robotic prostatectomy. A tri-zonal neural architecture is described which has helped in standardizing the steps of robotic prostatectomy.

Adult↗

PubMed2006

Robotic replacement of the descending aorta in human cadaver.

Robot-assisted replacement of the thoracic aorta was performed in a human cadaver. Temporary shunt bypass was established by inserting a left axillary artery catheter and directing it through the aortic arch toward the right femoral artery through the abdominal aorta. The technique utilized the da Vinci surgical system inserted through the 4-cm supramammary working port and two additional thoracoscopic ports. The working port allowed the introduction of an endoscope, endoscopic instruments, and artificial graft and suture materials. The aorta was dissected using the robotic instruments and was clamped with two transthoracic clamps. After transaction of the aorta, a 20-mm polytetrafluoroethylene graft was cut and an end-to-end anastomosis was then performed with running 3-0 Prolene sutures with robotic instruments. The robotic system provides superior optics and allows for enhanced dexterity. Minimally invasive robotic replacement of the descending aorta is an effective procedure and may add benefits for both surgeon and patients.

Aorta, Thoracic↗

PubMedDate not supplied

Minimally invasive videoscopic mitral valve surgery: the current role of surgical robotics.

OBJECTIVE: Recently, the efficacy of video-assisted mitral valve surgery has been demonstrated. The evolution of this technology has been relatively rapid. In this article we review this development and predict the future of endoscopic and robotic-enabling technology for cardiac valve operations. METHODS: A new video-assisted mitral valve operation is described and results discussed. The majority of each valve operation was done through assisted vision and near endoscopically. Cardiopulmonary bypass was established via femoral cannulation, and blood cardioplegic arrest induced using a new percutaneous, transthoracic cross-clamp. A 5 to 6-cm minithoracotomy was used in each patient. Videoscopy was helpful for suture placement, chord reconstruction, leaflet resection, knot tying, and valve ring or prosthesis positioning. A voice-activated robotic arm was used to direct the camera in many instances. RESULTS: Thus far a total of 110 patients have undergone this operation successfully with a 0.9% operative mortality. Our early series (N = 31), published with cost data, is reviewed in detail. Cardiopulmonary perfusion and cross-clamp times for all 100 patients were longer than for conventional sternotomy patients at 158 +/- 3.9 and 110 +/- 3.6 minutes, respectively, versus 121 +/- 4.6 and 90 +/- 4.6 (N = 105); however, there have been less complications. Operative, perfusion, and arrest times have fallen progressively to 144 +/- 4.5 and 90 +/- 4.5, respectively (N = 55 Aesop 3000 cases). Complex repairs and replacements have become routine with anterior leaflet pathology addressed. Bleeding, ventilatory times, blood transfusions, and hospital stay have been reduced. One patient required reoperation for a technically failed repair and two renal patients had late endocarditis. We have used voice-activated, robotic (Aesop 3000) assistance for camera control in 51 of these patients. This addition has decreased camera motion artifact and lens cleaning, while providing direct "cerebral-eye" tracking of instruments for the surgeon. We were the first in the United States to apply the DaVinci articulated wrist robot to do a complete mitral repair and have done multiple repair with this articulated wrist device. CONCLUSIONS: From this and other work reviewed, we conclude that video-assisted and computer-assisted robotic techniques are safe and may be the pathway to truly endoscopic mitral valve operations. We are encouraged regarding the use of this new technology for mitral valve operations.

Cardiopulmonary Bypass↗

PubMed2005

Full-state tracking control of a mobile robot using neural networks.

In this paper a nonholonomic mobile robot with completely unknown dynamics is discussed. A mathematical model has been considered and an efficient neural network is developed, which ensures guaranteed tracking performance leading to stability of the system. The neural network assumes a single layer structure, by taking advantage of the robot regressor dynamics that expresses the highly nonlinear robot dynamics in a linear form in terms of the known and unknown robot dynamic parameters. No assumptions relating to the boundedness is placed on the unmodeled disturbances. It is capable of generating real-time smooth and continuous velocity control signals that drive the mobile robot to follow the desired trajectories. The proposed approach resolves speed jump problem existing in some previous tracking controllers. Further, this neural network does not require offline training procedures. Lyapunov theory has been used to prove system stability. The practicality and effectiveness of the proposed tracking controller are demonstrated by simulation and comparison results.

Artificial Intelligence↗

PubMed1996

Manipulator adaptive control by neural networks in an orange picking robot.

The paper focuses on the use of neural networks for process identification in an orange-picking robot adaptive control system. The results that will be shown in the paper refer to a study carried out under the European Community ESPRIT project "CONNY", dealing with the application of neural networks to robotics. The aim of the research is to verify the possibility of integrating a neural identification module in a traditional system to control the movement of the manipulators of the robot. The paper illustrates integration of neural identification in the existing orange-picking robot control system, highlighting the improvement of performance obtainable. Although the proposal refers to a specific robot, it can be applied to any system with the same dynamic features.

Adaptation, Psychological↗

PubMed2004

Robotics, motor learning, and neurologic recovery.

Robotic devices are helping shed light on human motor control in health and injury. By using robots to apply novel force fields to the arm, investigators are gaining insight into how the nervous system models its external dynamic environment. The nervous system builds internal models gradually by experience and uses them in combination with impedance and feedback control strategies. Internal models are robust to environmental and neural noise, generalized across space, implemented in multiple brain regions, and developed in childhood. Robots are also being used to assist in repetitive movement practice following neurologic injury, providing insight into movement recovery. Robots can haptically assess sensorimotor performance, administer training, quantify amount of training, and improve motor recovery. In addition to providing insight into motor control, robotic paradigms may eventually enhance motor learning and rehabilitation beyond the levels possible with conventional training techniques.

Algorithms↗

PubMed2004

Robot-assisted laparoscopic Heller cardiomyotomy: preliminary UK results.

BACKGROUND/AIM: Laparoscopic Heller cardiomyotomy is an established modality in the surgical treatment of patients having achalasia cardia. We present our initial experience in robot-assisted laparoscopic Heller cardiomyotomy without addition of an antireflux procedure and discuss the relative merits and disadvantages of the procedure. PATIENTS AND METHODS: Five patients underwent robot-assisted laparoscopic Heller cardiomyotomy between August 2001 and October 2002. The diagnosis had been confirmed by radiology and manometry in all patients prior to surgery. RESULTS: All procedures were completed successfully using the robotic system, without conversion to open procedure. Mucosal perforation occurred in 1 patient and was sutured robotically. The average operative time was 114.8 (range 65-160) min which is comparable to laparoscopic procedures. After a mean follow-up period of 9.4 (range 3-17) months, 4 patients remained completely asymptomatic, and 1 patient has benefited from symptomatic improvement. CONCLUSIONS: The enhanced dexterity and the high-quality three-dimensional vision available with robot-assisted surgery make the application of this technology highly suitable for Heller cardiomyotomy. The minimal lateral and posterior dissection due to the wristed instruments avoids the need for an antireflux procedure.

Adult↗

PubMed2000

Connecting brains to robots: an artificial body for studying the computational properties of neural tissues.

We have created a hybrid neuro-robotic system that establishes two-way communication between the brain of a lamprey and a small mobile robot. The purpose of this system is to offer a new paradigm for investigating the behavioral, computational, and neurobiological mechanisms of sensory-motor learning in a unified context. The mobile robot acts as an artificial body that delivers sensory information to the neural tissue and receives command signals from it. The sensory information encodes the intensity of light generated by a fixed source. The closed-loop interaction between brain and robot generates autonomous behaviors whose features are strictly related to the structure and operation of the neural preparation. We provide a detailed description of the hybrid system, and we present experimental findings on its performance. In particular, we found (a) that the hybrid system generates stable behaviors, (b) that different preparations display different but systematic responses to the presentation of an optical stimulus, and (c) that alteration of the sensory input leads to short- and long-term adaptive changes in the robot responses. The comparison of the behaviors generated by the lamprey's brain stem with the behaviors generated by network models of the same neural system provides us with a new tool for investigating the computational properties of synaptic plasticity.

Animals↗

PubMed2002

Genetic redundancy in evolving populations of simulated robots.

A number of authors have argued that redundancy in biological organisms contributes to their evolvability. We investigate this hypothesis via the experimental manipulation of genetic redundancy in evolving populations of simulated robots controlled by artificial neural networks. A genetic algorithm is used to simulate the evolution of robots with the ability to perform a previously studied task. Redundancy is measured using systematic lesioning. In our experiments, populations of robots with larger genotypes achieve systematically higher fitness than populations whose genotypes are smaller. It is shown that, in principle, robots with smaller genotypes have enough computational power to achieve optimal fitness. Populations with larger (redundant) genotypes appear, however, to be more evolvable and display significantly higher diversity. It is argued that this enhanced evolvability is a direct effect of genetic redundancy, which allows populations of redundant robots to explore neutral networks spanning large areas of genotype space. We conjecture that, where cost considerations allow, redundancy in functional or potentially functional components of the genome may make a valuable contribution to evolution in artificial and perhaps in biological systems. The methods described in the article provide a practical way of testing this hypothesis for the artificial case.

Models, Genetic↗