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PubMed1997

Automatic head positioning system using PSD-equipped camera-based photostereometry and a 5-degree-of-freedom robotized chair: calibration and accuracy verification.

In measurements of jaw movements employing an X-ray television, the orientation of the patient's head must be normalized relative to the measuring device. To avoid interferring with natural jaw movements caused by using a positioning jig, we have developed an automatic head positioning system consisting of a head position sensor and a robotized chair. The position and orientation of the head is monitored by detecting the three-dimensional positions of four non-coplanar LED markers mounted on the head, by means of a set of two photoelectronic cameras. If they are incorrect, the head is moved into the required position, using a 5-degree-of-freedom robotized chair. To accomplish this accurately, the positional relations of system components must be determined precisely. This paper proposes a least-square technique of calibrating the relationship between the position sensor and the chair. Consequently, accurate positioning is achieved. Accuracy verification studies revealed that overall positioning errors lay within 2.42 mm and 1.28 degrees with respect to the position and orientation, respectively, if the markers are secured to the head support of the chair.

Biomechanical Phenomena↗

PubMed1997

Positional reproducibility of the patient's head normalized by a robotized chair-based automatic head-positioning system, Racs-N.

With a view to normalization of the head orientation without the use of a fixation jig for the measurement of jaw movement employing an X-ray television, we have been developing an automatic head-positioning system, Racs-N, consisting of a head-position sensor and a robotized chair. The head position is monitored in 6 degrees of freedom (d.o.f.) by using a position-sensitive detector (PSD) camera-based photostereometry. If they are incorrect, the robotized chair rectifies them automatically by adjusting the position and orientation of the head support in 5 d.o.f. (except the vertical position). The rectified position, however, has a certain margin of error, due to the mobility of the head relative to the head support. To improve this, we employed an iterative correction in that the positioning is repeated until the determined position converges. In experiments employing several subjects, this particular correction was verified to converge by more than six iterations and to be effective for the reduction of head-position errors.

Adult↗

PubMed1998

Robot-aided functional imaging: application to a motor learning study.

The purpose of this study was to examine the neural activity underlying an implicit motor learning task. In particular, our goals were to determine whether initial phases of procedural learning of a motor task involve areas of the brain distinct from those involved in later phases of learning the task, and what changes in neural activity coincide with performance improvement. We describe a novel integration of robotic technology with functional brain imaging and its use in this study of implicit motor learning. A portable robotic device was used to generate forces that disturbed the subjects' arm movements, thereby generating a "virtual mechanical environment" that the subjects learned to manipulate. Positron emission tomography (PET) was used to measure indices of neural activity underlying learning of the motor task. Eight health, right-handed male subjects participated in the study. Results support the hypothesis that different stages of implicit learning (early and late implicit learning) occur in an orderly fashion, and that distinct neural structures may be involved in these different stages. In particular, neuroimaging results indicate that the cortico-striatal loop may play a significant role during early learning, and that the cortico-cerebellar loop may play a significant role during late learning.

Adult↗

PubMed1998

Computer assisted orthopaedic surgery. Image guided and robotic assistive technologies.

Technologies are emerging that will influence the way in which orthopaedic surgery is planned, simulated, and performed. Recent advances in the fields of medical imaging, computer vision, and robotics have provided the enabling technologies to permit computer aided surgery to become an established area which can address clinical needs. Although these technologies have been applied in industry for more than 20 years, the field of computer assisted orthopaedic surgery is still in its infancy. Image guided and surgical navigation systems, robotic assistive devices, and surgical simulators have begun to emerge from the laboratory and hold the potential to improve current surgical practice and patients' outcomes. The goals of these new clinically focused technologies are to develop interactive, patient specific preoperative planners to optimize the performance of surgery and the postoperative biologic response, and develop more precise and less invasive interactive smart tools and sensors to assist in the accurate and precise performance of surgery. The medical community is beginning to see the benefit of these enabling technologies which can be realized only through the collaboration and combined expertise of engineers, roboticists, computer scientists, and surgeons.

Biomedical Engineering↗

PubMed2003

[Dislocated fracture of the lesser trochanter with malrotation of the stem after robot assisted implantation of a cementless hip prosthesis: a casuistic report].

This paper presents the case of a 63 year old female with a severe coxarthrosis. She got a robot assited implantation of a cementless hip prosthesis (Osteolock, Stryker-Howmedica, Mühlheim). As operation robot the CASPAR-System (Orto-Maquet, Rastatt) was used. Initially, the clinical progress of the patient was fine. She was nearly painfree within 14 days and showed an acceptable range of motion in the operated joint (flexion/ extension 90 degrees /05 degrees /00 degrees ). She was mobilized with crutches and 15 kg weight bearing at the operated leg. 3 weeks postoperative the patient complaint about increasing pain without trauma or intensification of the weight bearing. X-rays showed not only a dislocated fracture of the lesser trochanter, but also a sinking combined with a malrotation of the stem. A revision operation was necessary,where we implanted a cemented stem. Now clinical progress was completely satisfying.

Arthroplasty, Replacement, Hip↗

PubMed1997

Self-organizing Internal Representation in Learning of Navigation: A Physical Experiment by the Mobile Robot YAMABICO.

This paper discusses a novel scheme for sensory-based navigation of a mobile robot. In our previous work ([Tani and Fukumura, 1994], Neural Networks, 7(3), 553-563), we formulated the problem of goal-directed navigation as an embedding problem of dynamical systems: desired trajectories in a task space should be embedded in an adequate sensory-based internal state space so that a unique mapping from the internal state space to the motor command could be established. In the current formulation a recurrent neural network is employed, which shows that an adequate internal state space can be self-organized, through supervised training with sensorimotor sequences. The experiment was conducted using a real mobile robot equipped with a laser range sensor, demonstrating the validity of the presented scheme by working in a noisy real-world environment. Copyright 1996 Elsevier Science Ltd.

Journal Article↗

PubMed1998

A tennis serve and upswing learning robot based on bi-directional theory.

We experimented on task-level robot learning based on bi-directional theory. The via-point representation was used for 'learning by watching'. In our previous work, we had a robot learn kendama (a Japanese game) in order to demonstrate a single simple task. Our approach can be applied to a wide variety of motor behavior. However, some difficulties still remain. In this paper, we address two problems: (1) how to attain a final goal of complex movement when it consists of a sequence of subgoals, and (2) how to adapt to changes in behavior and the environment. To examine how to solve these problems, we propose two methods: (1) selecting the proper via-points for a control variable for each subgoal, and (2) re-estimating the relation between the via-points and the task during learning without conducting extra trials. We adopted a tennis serve and a pendulum upswing for our complicated tasks.

Journal Article↗

PubMed1998

Robots, crickets and ants: models of neural control of chemotaxis and phonotaxis.

Neural control in animals can be investigated using robot models. Two simple behaviours are focused on: pheromone trail following in ants and sound source localization in crickets. Our models address the real sensorimotor constraints and physiological underpinnings of these behaviours. Using alcohol gas sensors on a robot it is shown that a simple neural architecture can reproduce a range of trail-following behaviours that qualitatively resemble the results reported for ants. Building a more detailed auditory sensor based on the cricket ear it is shown that preference for song frequency and pattern does not require a recognition mechanism, using real cricket song as stimuli. Finally the spiking neuron models that enable us to examine exactly how these robust forms of motor control can emerge from small networks of neurons are introduced.

Journal Article↗

PubMed2001

Robotic stabilisation assisting cardiac surgery on beating hearts.

Minimally invasive direct coronary artery bypass (MIDCAB) requires precise work on beating hearts and demands of surgeons' manual dexterity and mental concentration. We propose a surgical robot system that compensates for motions of organs during operations. The motion-cancelling robot system consists of three technologies: visual synchronisation, motion synchronisation and master-slave control. In this paper, we verify the effectiveness of the prototype system by an in vivo experiment.

Journal Article↗

PubMed1996

Totally automated analysis by robotized PrepStation and liquid chromatography: direct-sample analysis of felbamate.

A totally automated analysis of felbamate was developed by using a robotized PrepStation for extraction, followed by automated liquid chromatographic (LC) analysis and data reduction. This is one of the newer direct-sample analysis approaches by LC. Felbamate was a previously approved antiepileptic agent used to treat partial seizures with and without generalization and to treat Lennox-Gastaut syndrome in pediatric patients. However, due to the reported incidences of aplastic anemia, its clinical application was recently restricted to the treatment of the latter syndrome. The automated assay using Bench Supervisor, PrepStation, and LC, based on a previously developed manual method, used 200 microliters of serum standards, quality control, or patients' plasma. These were mixed with 600 microliters of internal standard (IS) W509 dissolved in acetonitrile for protein precipitation. After axial centrifugation and standing, aliquots of the clear supernatant were transferred and washed with hexane. Aliquots of the supernatant were transferred and injected into a high-performance liquid chromatograph (HPLC). HPLC parameters included an mu Bondapak C-18 column, phosphate/acetonitrile (8:2) as mobile phase, and detection at 214 nm. Retention times were 2.9 and 4.2 min for felbamate and IS, respectively. Calibration was linear for concentrations from 10 to 200 mg/L with r > 0.994. Precision studies showed coefficients of variation ranging from 2.7% to 8.8%. Correlation with the manual method showed that r = 0.934, slope = 1.048, intercept = -2.642, and n = 21. Phenobarbital coeluted with the IS. This study demonstrated the feasibility of using a robotized, automated method for monitoring felbamate, readily extended to monitoring other antiepileptic drugs with minimal modification.

Anticonvulsants↗

PubMed2004

Methods for haptic feedback in teleoperated robot-assisted surgery.

Teleoperated minimally invasive surgical robots can significantly enhance a surgeon's accuracy, dexterity and visualization. However, current commercially available systems do not include significant haptic (force and tactile) feedback to the operator. This paper describes experiments to characterize this problem, as well as several methods to provide haptic feedback in order to improve surgeon's performance. There exist a variety of sensing and control methods that enable haptic feedback, although a number of practical considerations, e.g. cost, complexity and biocompatibility, present significant challenges. The ability of teleoperated robot-assisted surgical systems to measure and display haptic information leads to a number of additional exciting clinical and scientific opportunities, such as active operator assistance through "virtual fixtures" and the automatic acquisition of tissue properties.

Journal Article↗

PubMed2004

Global asymptotic stability of a tracking sectorial fuzzy controller for robot manipulators.

This paper shows that fuzzy control systems satisfying sectorial properties are effective for motion tracking control of robot manipulators. We propose a controller whose structure is composed by a sectorial fuzzy controller plus a full nonlinear robot dynamics compensation, in such a way that this structure leads to a very simple closed-loop system represented by an autonomous nonlinear differential equation. We demonstrate via Lyapunov theory, that the closed-loop system is globally asymptotically stable. Experimental results show the feasibility of the proposed controller.

Journal Article↗

PubMed2004

Improve the robot calibration accuracy using a dynamic online fuzzy error mapping system.

Traditional robot calibration implements model and modeless methods. The compensation of position error in modeless method is to move the end-effector of robot to the target position in the workspace, and to find the position error of that target position by using a bilinear interpolation method based on the neighboring 4-point's errors around the target position. A camera or other measurement devices can be utilized to find or measure this position error, and compensate this error with the interpolation result. This paper provides a novel fuzzy interpolation method to improve the compensation accuracy obtained by using a bilinear interpolation method. A dynamic online fuzzy inference system is implemented to meet the needs of fast real-time control system and calibration environment. The simulated results show that the compensation accuracy can be greatly improved by using this fuzzy interpolation method compared with the bilinear interpolation method.

Journal Article↗

PubMed1984

Automation of chromogenic substrate Limulus amebocyte lysate assay method for endotoxin by robotic system.

The chromogenic substrate Limulus amebocyte lysate (LAL) assay method for the detection of endotoxin was automated by a Zymate robotic system. The software developed enables the robot to automatically dilute a stock reference endotoxin standard (20,000 endotoxin units per ml) for the construction of a five-point standard curve, make sample dilutions to the proper testing concentration, and perform chromogenic substrate LAL assays in duplicate. The linearity of the standard curve and the endotoxin concentration in each sample are calculated and results are printed automatically. In 48 min the automated system assays three samples and a reference standard in duplicate along with a water blank. Sensitivity of the assay is a function of incubation time. The assay is linear (r greater than 0.99) in the region of 0 to 1.0 endotoxin units per ml or 0 to 0.2 endotoxin units per ml with incubation times of 10 or 16 min, respectively. The method can be made very sensitive, detecting as low as 0.003 endotoxin units per ml with 30 min of incubation. The precision of the assay method, determined by assaying an endotoxin reference solution eight times, is ca. 6%. The LAL reagent designed for gel-clot assay was modified for the chromogenic substrate assay. We describe the optimum conditions for the performance of the chromogenic substrate LAL assay and stability of the LAL reagent.

Automation↗

PubMed2006

High-throughput screening of cellulase F mutants from multiplexed plasmid sets using an automated plate assay on a functional proteomic robotic workcell.

BACKGROUND: The field of plasmid-based functional proteomics requires the rapid assay of proteins expressed from plasmid libraries. Automation is essential since large sets of mutant open reading frames are being cloned for evaluation. To date no integrated automated platform is available to carry out the entire process including production of plasmid libraries, expression of cloned genes, and functional testing of expressed proteins. RESULTS: We used a functional proteomic assay in a multiplexed setting on an integrated plasmid-based robotic workcell for high-throughput screening of mutants of cellulase F, an endoglucanase from the anaerobic fungus Orpinomyces PC-2. This allowed us to identify plasmids containing optimized clones expressing mutants with improved activity at lower pH. A plasmid library of mutagenized clones of the celF gene with targeted variations in the last four codons was constructed by site-directed PCR mutagenesis and transformed into Escherichia coli. A robotic picker integrated into the workcell was used to inoculate medium in a 96-well deep well plate, combining the transformants into a multiplexed set in each well, and the plate was incubated on the workcell. Plasmids were prepared from the multiplexed culture on the liquid handler component of the workcell and used for in vitro transcription/translation. The multiplexed expressed recombinant proteins were screened for improved activity and stability in an azo-carboxymethylcellulose plate assay. The multiplexed wells containing mutants with improved activity were identified and linked back to the corresponding multiplexed cultures stored in glycerol. Spread plates were prepared from the glycerol stocks and the workcell was used to pick single colonies from the spread plates, prepare plasmid, produce recombinant protein, and assay for activity. The screening assay and subsequent deconvolution of the multiplexed wells resulted in identification of improved CelF mutants and corresponding optimized clones in expression-ready plasmids. CONCLUSION: The multiplex method using an integrated automated platform for high-throughput screening in a functional proteomic assay allows rapid identification of plasmids containing optimized clones ready for use in subsequent applications including transformations to produce improved strains or cell lines.

Journal Article↗

PubMed1992

Robot system for preparing lymphocyte chromosome.

Towards the automatization of the scoring of chromosome aberrations in radiation dosimetry with the emphasis on the improvement of biological preparations, the conventional culture and harvesting method was modified. Based on this modified method, a culture and harvest robotic system (CHROSY) for system (CHROSY) for preparing lymphocyte chromosome was developed. The targeted points of the modification are as in the following. 1. Starting culture with purified lymphocytes in a fixed cell number. 2. Avoiding the loss of cells in changing the liquids following centrifugalization. 3. Keeping the quantity of the liquids to be applied to the treatments of cells fixed. 4. Building a system even a beginner can handle. System features are as follows. 1. Operation system: Handling robot having 5 degrees of freedom; a rotator incubator with an automatic sliding door; units for setting and removing pipette tips; a centrifuge equipped with a position adjuster and an automatic sliding door; two aluminum block baths; two nozzles as pipettes and aspirators connected to air pumps; a capping unit with a nozzle for CO2 gas; a compressor; and an air manipulated syringe. 2. Control system: NEC PC-9801RX21 with CRT; and program written in Basic and Assembly languages on MS-DOS. It took this system 2 hours and 25 minutes to harvest 2 cultures. A fairly good chromosome slide was made from the sample harvested by CHROSY automatically.

Chromosomes↗

PubMed2002

Robot-aided neurorehabilitation: from evidence-based to science-based rehabilitation.

There is no "magic bullet" in rehabilitation. In the absence of direct neural transplants, neurological rehabilitation is an arduous process. We have pioneered the clinical application of robotics in stroke rehabilitation and have shown evidence of the positive impact of targeted exercise on stroke recovery. In this article, we will review results obtained in the initial clinical trials with 96 stroke patients at the Burke Rehabilitation Hospital. We will provide evidence that robot-aided training enhances recovery, that this enhanced recovery is sustained in the long term, and that this recovery is not due to a general physiological improvement--in fact, it appears to be limb and muscle group specific. An evidence-based approach must now segue into a more scientific approach to stroke rehabilitation. Given the length of the required protocols and patients' variability and limited census, the practical limitations of the evidence-based approach are self-evident and extend trials for years. Each patient and lesion is unique in stroke rehabilitation, so there is no reason to believe that a "one-size-fits-all" optimal treatment exists. To optimize therapy for individual patients, we need science-based models. In this article, we will summarize the scientific tools and models that we are investigating and present some of the results to date.

Journal Article↗

PubMed2002

Robotic devices for movement therapy after stroke: current status and challenges to clinical acceptance.

Robotic devices for movement therapy are moving closer to becoming commercially available tools for aiding in stroke rehabilitation. Robotic technology offers a range of functions that will augment current clinical practice by leveraging therapists' time, cost effectively extending therapy programs, providing new measures of impairment, and offering new therapy protocols. In this article, we review work from several research laboratories that supports the clinical value of stroke therapy systems. A commercialization effort based on these results is described. We also discuss challenges to achieving clinical acceptance and practical implementation of these devices.

Journal Article↗