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At least 1,531 records · Page 85Linked to original sources
PubMed2005

Development of a fully automated macromolecular crystallization/observation robotic system, HTS-80.

A robotic system has been developed to be used for macromolecular crystallization and observation in typical university laboratories with a research focus on protein crystallography. The system consists of three major parts: a dispenser unit, a storage unit and an observation unit. This system is designed to automatically perform all of the processes involved in crystallization and observation without requiring any manual operations. The dispenser and observation units can carry out both sitting-drop vapor-diffusion procedures and microbatch procedures. With this system, the procedures are controlled by a personal computer running GUI-based software. After the dispensing of protein solution into the crystallization plates, they are automatically transferred to the storage units, followed by automatic observation according to a required schedule with arbitrary intervals. At each stage of crystallization, droplets in the crystallization plates are examined by original image-processing software in order to evaluate the appearance of the crystals.

Crystallization↗
PubMed2006

Integrated software for macromolecular crystallography synchrotron beamlines II: revision, robots and a database.

This manuscript chronicles the evolution of software used originally to control a diffractometer at a macromolecular crystallography beamline. The system has been augmented and rewritten. A modular and carefully organized suite of programs now handles the whole experimental environment from a single vantage point. It provides automatic logging of the experiment and communication with the user, all the way from an initial proposal to perform the work to the end of data collection. This has included construction of a relational database to organize all details of the experiment and incorporation of a robotic specimen changer to provide automation for high-throughput applications.

Crystallography↗
PubMed1998

Three-dimensional reconstruction of live embryos using robotic macroscope images.

To determine the three-dimensional (3-D) shape of a live embryo is a technically challenging task. We show that reconstructions of live embryos can be done by collecting images from different viewing angles using a robotic macroscope, establishing point correspondences between these views by block matching, and using a new 3-D reconstruction algorithm that accommodates camera positioning errors. The algorithm assumes that the images are orthographic projections of the object and that the camera scaling factors are known. Point positions and camera errors are found simultaneously. Reconstructions of test objects and embryos show that meaningful reconstructions are possible only when camera positioning and alignment errors are accommodated since these errors can be substantial. Reconstructions of early-stage axolotl embryos were made from sets of 33 images. In a typical reconstruction, 781 points, each visible in at least three different views, were used to form 1511 triangles to represent the embryo surface. The resulting reconstruction had a mean radius of error of 0.27 pixels (1.1 microns). Mathematical properties of the reconstruction algorithm are identified and discussed.

Algorithms↗
PubMed1998

The NavBelt--a computerized travel aid for the blind based on mobile robotics technology.

This paper presents a new concept for a travel aid for the blind. A prototype device, called the NavBelt, was developed to test this concept. The device can be used as a primary or secondary aid, and consists of a portable computer, ultrasonic sensors, and stereophonic headphones. The computer applies navigation and obstacle avoidance technologies that were developed originally for mobile robots. The computer then uses a stereophonic imaging technique to process the signals from the ultrasonic sensors and relays their information to the user via stereophonic headphones. The user can interpret the information as an acoustic "picture" of the surroundings, or, depending on the operational mode, as the recommended travel direction. The acoustic signals are transmitted as discrete beeps or continuous sounds. Experimental results with the NavBelt simulator and a portable prototype show that users can travel safely in an unfamiliar and cluttered environment at speeds of up to 0.8 m/s.

Acoustics↗
PubMed2002

Classification of finger activation for use in a robotic prosthesis arm.

Hand amputees would highly benefit from a robotic prosthesis, which would allow the movement of a number of fingers. In this paper we propose using the electromyographic signals recorded by two pairs of electrodes placed over the arm for operating such prosthesis. Multiple features from these signals are extracted whence the most relevant features are selected by a genetic algorithm as inputs for a simple classifier. This method results in a probability of error of less than 2%.

Adult↗
PubMed2005

Robot-enhanced motor learning: accelerating internal model formation during locomotion by transient dynamic amplification.

When adapting to novel dynamic environments the nervous system learns to anticipate the imposed forces by forming an internal model of the environmental dynamics in a process driven by movement error reduction. Here, we tested the hypothesis that motor learning could be accelerated by transiently amplifying the environmental dynamics. A novel dynamic environment was created during treadmill stepping by applying a perpendicular viscous force field to the leg through a robotic device. The environmental dynamics were amplified by an amount determined by a computational learning model fit on a per-subject basis. On average, subjects significantly reduced the time required to predict the applied force field by approximately 26% when the field was transiently amplified. However, this reduction was not as great as that predicted by the model, likely due to nonstationarities in the learning parameters. We conclude that motor learning of a novel dynamic environment can be accelerated by exploiting the error-based learning mechanism of internal model formation, but that nonlinearities in adaptive response may limit the feasible acceleration. These results support an approach to movement training devices that amplify rather than reduce movement errors, and provide a computational framework for both implementing the approach and understanding its limitations.

Adaptation, Physiological↗
PubMed2005

Experimental results using force-feedback cueing in robot-assisted stroke therapy.

Stroke is the leading cause of disability among adults in the United States. Behaviors such as learned nonuse hinder hemiplegic stroke survivors from the full use of both arms in activities of daily living. Active force-feedback cues, designed to restrain the use of the less-affected arm, were embedded into a meaningful driving simulation environment to create robot-assisted therapy device, driver's simulation environment for arm therapy (SEAT). The study hypothesized that force-feedback control mode could "motivate" stroke survivors to increase the productive use of their impaired arm throughout a bilateral steering task, by providing motivating feedback and reinforcement cues to reduce the overuse of the less-affected arm. Experimental results demonstrate that the force cues counteracted the tendency of hemiplegic subjects to produce counter-productive torques only during bilateral steering tasks (p < 0.05) that required the movement of their impaired arm in steering directions up and against gravity. Impaired arm activity was quantified in terms of torques due to the measured tangential forces on the split-steering wheel of driver's SEAT during bilateral steering. Results were verified using surface electromyograms recorded from key muscles in the impaired arm.

Aged↗
PubMed2006

Robotic personal aids for mobility and monitoring for the elderly.

Two rehabilitation devices, or personal aids for mobility and monitoring (PAMM), for use by the elderly are presented. The devices are intended to delay the transition from eldercare (assisted living) facilities to nursing homes. The robotic PAMMs provide support, guidance, and health monitoring. Two experimental systems are described: a cane and a walker. Issues of mobility, sensing, and control, as well as experimental data from trials in an assisted living facility using both systems are presented.

Aged↗
PubMed2004

Nonlinear visual mapping model for 3-D visual tracking with uncalibrated eye-in-hand robotic system.

A new control scheme for uncalibrated robotic visual tracking problem is proposed that compromises the computational expenses of overall system with offline modeling and online control. A nonlinear visual mapping model for the uncalibrated hand-eye coordination is first proposed with an artificial neural network implementation. An online visual tracking controller is then developed together with a real-time motion planner. To improve the system performance, the control scheme is also integrated with a feedforward controller to compensate unknown object motions. Extensive simulations and experiments demonstrate the effectiveness of the proposed control scheme.

Algorithms↗
PubMed2005

A primal-dual neural network for online resolving constrained kinematic redundancy in robot motion control.

This paper proposes a primal-dual neural network with a one-layer structure for online resolution of constrained kinematic redundancy in robot motion control. Unlike the Lagrangian network, the proposed neural network can handle physical constraints, such as joint limits and joint velocity limits. Compared with the existing primal-dual neural network, the proposed neural network has a low complexity for implementation. Compared with the existing dual neural network, the proposed neural network has no computation of matrix inversion. More importantly, the proposed neural network is theoretically proved to have not only a finite time convergence, but also an exponential convergence rate without any additional assumption. Simulation results show that the proposed neural network has a faster convergence rate than the dual neural network in effectively tracking for the motion control of kinematically redundant manipulators.

Algorithms↗
PubMed2005

Mixed H2/H infinity design for a decentralized discrete variable structure control with application to mobile robots.

In this paper, a decentralized discrete variable structure control via mixed H2/H infinity design was developed. In the beginning, the H2-norm of output error and weighted control input was minimized to obtain a control such that smaller energy consumption with bounded tracking error was assured. In addition, a suitable selection of this weighted function (connected with frequency) could reduce the effect of disturbance on the control input. However, an output disturbance caused by the interactions among subsystems, modeling error, and external load deteriorated system performance or even brought about instability. In this situation, the H infinity-norm of weighted sensitivity between output disturbance and output error was minimized to attenuate the effect of output disturbance. Moreover, an appropriate selection of this weighted function (related to frequency) could reject the corresponding output disturbance. No solution of Diophantine equation was required; the computational advantage was especially dominated for low-order system. For further improving system performance, a switching control for every subsystem was designed. The proposed control (mixed H2/H infinity DDVSC) was a three-step design method. The stability of the overall system was verified by Lyapunov stability criterion. The simulations and experiments of mobile robot were carried out to evaluate the usefulness of the proposed method.

Algorithms↗
PubMed2002

A visual equalization strategy for locomotor control: of honeybees, robots, and humans.

Honeybees fly down the center of a corridor by equating the speed of optic flow in the lateral field of the two eyes. This flow-equalization strategy has been successfully implemented in mobile robots to guide behavior in cluttered environments. We investigated whether humans use a similar strategy to steer down a corridor and determined the relative contributions of equating the speed of flow (.27), the splay angles of base lines (.62), and the visual angles of texture on the left and right walls (.03) to steering behavior. A generalized equalization strategy based on the weighted linear combination of these variables closely models human behavior, providing robust visual control.

Animals↗
PubMed1988

Considerations in the use of laboratory robots: aspects of safety and accuracy.

A general-purpose laboratory robot was configured to prepare blood samples for the HBsAg and anti-HIV tests. Several issues were studied in order to eliminate problems and optimize the system. These included pipetting accuracy, intersample carryover, reagent interference, splashing and aerosol generation and user-related issues. A number of general guidelines were developed to assist others in developing and implementing systems for this and similar applications.

Evaluation Studies as Topic↗
PubMed2005

Robot-assisted vs pure laparoscopic radical prostatectomy: are there any differences?

OBJECTIVE: To compare our experience of pure laparoscopic radical prostatectomy (LRP) with robot-assisted radical prostatectomy (RAP). PATIENTS AND METHODS: The two techniques were compared retrospectively in 100 patients with localized prostate cancer who had LRP or RAP (50 each). Both groups were similar in age, serum prostate-specific antigen level, Gleason score and clinical stage. Their charts were reviewed, collating intraoperative data and early functional outcome. RESULTS: The mean surgical time for LRP and RAP was 235 and 202 min (P > 0.05) and mean (95% confidence interval) blood loss 299 (40) and 206 (63) mL (P = 0.014), with no transfusions in either group. The positive margin rate did not differ significantly (14% LRP and 12% RAP) and there was no biochemical recurrence in either group. Early functional outcomes were similar. CONCLUSIONS: Both LRP and RAP are technically demanding, but feasible, with the patient clearly benefiting. There were no major surgical differences between the techniques, but RAP is more costly.

Erectile Dysfunction↗
PubMed2006

Positive influence of robotically assisted laparoscopic prostatectomy on the collaborative-care pathway for open radical prostatectomy.

OBJECTIVE: To define changes in the clinical pathway for open radical retropubic prostatectomy (RRP) and to determine their impact on patient care under the indirect influence of minimally invasive prostatectomy after implementing robotically assisted laparoscopic prostatectomy (RALP) at our institution and modifying the collaborative-care pathway. PATIENTS AND METHODS: We retrospectively reviewed the Vanderbilt Prostate Database since the initiation of RALP in May 2003, evaluating those patients who had open RRP. Data were analysed in three consecutive 5-month blocks to determine incremental changes in protocol and outcomes, including complications and re-admissions. RESULTS: Between May 2003 and August 2004, 196 patients had RALP and 183 had RRP. After May 2003, there was a progressive reduction for open RRP in the length of stay from 1.6 to 1.3 days. Analysis also showed an elimination of patient-controlled analgesia, a rapid diet advancement, and drain removal at the surgeon's discretion. There were no major complications after surgery, and three minor complications (1.6%). The rate of re-admission after open RRP was low throughout the study period (seven patients, 3.8%), and did not increase progressively. CONCLUSIONS: The management after open RRP was modified substantially after implementing RALP, with the two clinical pathways now similar. Despite these modifications in the treatment of patients having open RRP there was no increase in morbidity or compromise in patient outcome. Indeed, this study shows the feasibility and safety of a 1-day length of stay for open RRP.

Feasibility Studies↗
PubMed2006

Identification of the retrotrigonal layer as a key anatomical landmark during robotically assisted radical prostatectomy.

OBJECTIVE: To define the gross and microscopic anatomy, and the surgical significance, of the newly described retrotrigonal layer of the bladder neck, as an aid during robotic radical prostatectomy (RRP). MATERIALS AND METHODS: The data for this study were obtained from five fresh cadaveric dissections and 100 consecutive RRPs. Five male cadavers with no previous pelvic or urethral surgery were dissected to expose the posterior bladder neck and identify the retrotrigonal layer. This same layer was reproducibly identified in all 100 RRPs. The gross appearance of this layer, and its relationship to neighbouring structures, was documented using still photographs and intraoperative video. The microscopic composition of this layer was assessed using routine haematoxylin and eosin stains, and special staining for smooth muscle (desmin), neural tissue (S-100), and elastin. RESULTS: Grossly, the retrotrigonal layer is a well-defined midline strip located posterior to the bladder neck, that extends from the trigone (superiorly) to the base of the prostate (inferiorly). Microscopically, this layer was predominantly composed of smooth muscle with intervening connective tissue. The retrotrigonal layer serves as a key anatomical landmark to facilitate posterior prostatic dissection, particularly in men with large prostates, prominent median lobes, or previous transurethral prostatic surgery. Further, in our practice, this layer marks the posterior limit of dissection in which electrocautery is still used. Finally, the retrotrigonal layer serves to buttress the posterior layer of the urethrovesical anastomosis. CONCLUSION: The retrotrigonal layer is a key landmark during the posterior bladder neck dissection in the antegrade technique of RRP.

Adult↗
PubMed2006

Anatomical foundations and surgical manoeuvres for precise identification of the prostatovesical junction during robotic radical prostatectomy.

OBJECTIVE: To develop a technique to identify the bladder neck during robotic radical prostatectomy (RRP) using anatomical and patient studies, and to evaluate its efficacy during and after surgery. PATIENTS AND METHODS: The data for this study were from 10 fresh cadaveric dissections and 50 consecutive athermal RRPs performed at our institution. We used a technique we term 'the bimanual bladder neck pinch'. RESULTS: The technique helped us to identify the prostatovesical junction and to decrease the time required to dissect the bladder neck, and the time for urethrovesical anastomosis. Urinary continence requiring 0-1 pads was 29% at 1 week , 62% at 6 weeks, 88% at 12 weeks, and 95% at 16 weeks. No patient in the series had a clinically significant leak or urinary retention. CONCLUSIONS: Our technique of the 'bimanual pinch' is easy to learn and has reduced the difficulty of bladder neck transection. It improved the outcome both during and after RRP in our series.

Adult↗