Force control of heavy lift manipulators for high precision insertion tasks

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, June 2005."May 2005." Leaf 81 blank.Includes bibliographical references (leaves 67-70).The inherent strength of robotic manipulators can be used to assist humans in performing heavy lifting tasks. These robots reduce manpower, reduce fatigue, and increase productivity. This thesis deals with the development of a control system for a robot being built for this purpose. The task for this robot is to lift heavy payloads while performing complex insertion tasks. This task must be completed on the deck of a naval vessel where possible disturbances include wind, rain, poor visibility, and dynamic loads induced by a swaying deck. The primary objective of the controller being designed here is to allow for insertion of the payload despite tight positioning tolerances and disturbances like surface friction, joint friction, and dynamic loads from ship motions. A control structure designed for intuitive interaction between the robot and operator is analyzed and shown to be stable using an established environment interaction model. The controller is shown to perform within established specifications via numerical simulation based on simple user inputs. An additional objective of this controller design is to prevent part jamming during the insertion task. With a large, powerful manipulator, the chances of a jam occurring is high. Without the use of bilateral force feedback, it will be difficult for the operator feel when these jams will occur and there will be no information about how to prevent them. This thesis analyzes the geometry and mechanics of the jamming problem and derives a control system to assist the user in preventing these jams. These methods can be extended to other insertion tasks simply by specifying the appropriate geometry.by Matthew A. DiCicco.S.M

In vitro synergism of fosfomycin and clarithromycin antimicrobials against methicillin-resistant Staphylococcus pseudintermedius

BACKGROUND: Bacterial biofilms are of tremendous concern for clinicians, as they can compromise the ability of the immune system and antimicrobial therapy to resolve chronic and recurrent infections. Novel antimicrobial therapies or combinations targeted against biofilm establishment and growth subsequently represent a promising new option for the treatment of chronic infectious diseases. In this study, we treated bacterial biofilms produced by methicillin-resistant Staphylococcus pseudintermedius (MRSP) with a combination of fosfomycin and clarithromycin. We selected these agents, because they prevent biofilm formation and induce antimicrobial synergism that may also target other staphylococci. RESULTS: We determined that the combination of fosfomycin and clarithromycin better impairs S. pseudintermedius biofilm formation compared to treatment with either therapy alone (P < 0.05). Morphological examination of these biofilms via scanning electron microscopy demonstrated that fosfomycin alone does impact biofilm formation on orthopaedic implants. However, this activity is enhanced in the presence of clarithromycin. We propose that the bacteriostatic activity of clarithromycin is accentuated when fosfoymcin is present, as it may allow better penetration into the biofilm matrix, allowing fosfomycin access to sessile bacteria near the surface of attachment. CONCLUSIONS: Here, we demonstrate that the combination of fosfomycin and clarithromycin may be a useful therapy that could improve the clinical outcomes of treating antimicrobial resistant MRSP biofilms

Mars Technology Rover with Arm-Mounted Percussive Coring Tool, Microimager, and Sample-Handling Encapsulation Containerization Subsystem

A report describes the PLuto (programmable logic) Mars Technology Rover, a mid-sized FIDO (field integrated design and operations) class rover with six fully drivable and steerable cleated wheels, a rocker-bogey suspension, a pan-tilt mast with panorama and navigation stereo camera pairs, forward and rear stereo hazcam pairs, internal avionics with motor drivers and CPU, and a 5-degrees-of-freedom robotic arm. The technology rover was integrated with an arm-mounted percussive coring tool, microimager, and sample handling encapsulation containerization subsystem (SHEC). The turret of the arm contains a percussive coring drill and microimager. The SHEC sample caching system mounted to the rover body contains coring bits, sample tubes, and sample plugs. The coring activities performed in the field provide valuable data on drilling conditions for NASA tasks developing and studying coring technology. Caching of samples using the SHEC system provide insight to NASA tasks investigating techniques to store core samples in the future

In vitro synergism of fosfomycin and clarithromycin antimicrobials against methicillin-resistant Staphylococcus pseudintermedius

Abstract Background: Bacterial biofilms are of tremendous concern for clinicians, as they can compromise the ability of the immune system and antimicrobial therapy to resolve chronic and recurrent infections. Novel antimicrobial therapies or combinations targeted against biofilm establishment and growth subsequently represent a promising new option for the treatment of chronic infectious diseases. In this study, we treated bacterial biofilms produced by methicillin-resistant Staphylococcus pseudintermedius (MRSP) with a combination of fosfomycin and clarithromycin. We selected these agents, because they prevent biofilm formation and induce antimicrobial synergism that may also target other staphylococci. Results: We determined that the combination of fosfomycin and clarithromycin better impairs S. pseudintermedius biofilm formation compared to treatment with either therapy alone (P &lt; 0.05). Morphological examination of these biofilms via scanning electron microscopy demonstrated that fosfomycin alone does impact biofilm formation on orthopaedic implants. However, this activity is enhanced in the presence of clarithromycin. We propose that the bacteriostatic activity of clarithromycin is accentuated when fosfoymcin is present, as it may allow better penetration into the biofilm matrix, allowing fosfomycin access to sessile bacteria near the surface of attachment. Conclusions: Here, we demonstrate that the combination of fosfomycin and clarithromycin may be a useful therapy that could improve the clinical outcomes of treating antimicrobial resistant MRSP biofilms

An Architecture for Online Affordance-based Perception and Whole-body Planning

The DARPA Robotics Challenge Trials held in December 2013 provided a landmark demonstration of dexterous mobile robots executing a variety of tasks aided by a remote human operator using only data from the robot's sensor suite transmitted over a constrained, field-realistic communications link. We describe the design considerations, architecture, implementation and performance of the software that Team MIT developed to command and control an Atlas humanoid robot. Our design emphasized human interaction with an efficient motion planner, where operators expressed desired robot actions in terms of affordances fit using perception and manipulated in a custom user interface. We highlight several important lessons we learned while developing our system on a highly compressed schedule

Basic science232. Certolizumab pegol prevents pro-inflammatory alterations in endothelial cell function

Background: Cardiovascular disease is a major comorbidity of rheumatoid arthritis (RA) and a leading cause of death. Chronic systemic inflammation involving tumour necrosis factor alpha (TNF) could contribute to endothelial activation and atherogenesis. A number of anti-TNF therapies are in current use for the treatment of RA, including certolizumab pegol (CZP), (Cimzia ®; UCB, Belgium). Anti-TNF therapy has been associated with reduced clinical cardiovascular disease risk and ameliorated vascular function in RA patients. However, the specific effects of TNF inhibitors on endothelial cell function are largely unknown. Our aim was to investigate the mechanisms underpinning CZP effects on TNF-activated human endothelial cells. Methods: Human aortic endothelial cells (HAoECs) were cultured in vitro and exposed to a) TNF alone, b) TNF plus CZP, or c) neither agent. Microarray analysis was used to examine the transcriptional profile of cells treated for 6 hrs and quantitative polymerase chain reaction (qPCR) analysed gene expression at 1, 3, 6 and 24 hrs. NF-κB localization and IκB degradation were investigated using immunocytochemistry, high content analysis and western blotting. Flow cytometry was conducted to detect microparticle release from HAoECs. Results: Transcriptional profiling revealed that while TNF alone had strong effects on endothelial gene expression, TNF and CZP in combination produced a global gene expression pattern similar to untreated control. The two most highly up-regulated genes in response to TNF treatment were adhesion molecules E-selectin and VCAM-1 (q 0.2 compared to control; p > 0.05 compared to TNF alone). The NF-κB pathway was confirmed as a downstream target of TNF-induced HAoEC activation, via nuclear translocation of NF-κB and degradation of IκB, effects which were abolished by treatment with CZP. In addition, flow cytometry detected an increased production of endothelial microparticles in TNF-activated HAoECs, which was prevented by treatment with CZP. Conclusions: We have found at a cellular level that a clinically available TNF inhibitor, CZP reduces the expression of adhesion molecule expression, and prevents TNF-induced activation of the NF-κB pathway. Furthermore, CZP prevents the production of microparticles by activated endothelial cells. This could be central to the prevention of inflammatory environments underlying these conditions and measurement of microparticles has potential as a novel prognostic marker for future cardiovascular events in this patient group. Disclosure statement: Y.A. received a research grant from UCB. I.B. received a research grant from UCB. S.H. received a research grant from UCB. All other authors have declared no conflicts of interes

Efficacy of clarithromycin on biofilm formation of methicillin-resistant Staphylococcus pseudintermedius

Background: Surgical site infections (SSIs) caused by biofilm-forming methicillin-resistant Staphylococcus pseudintermedius (MRSP) have emerged as the most common hospital-acquired infections in companion animals. No methods currently exist for the therapeutic remediation of SSIs caused by MRSP in biofilms. Clarithromycin (CLA) has been shown to prevent biofilm formation by Staphylococcus aureus. This study aims to assess the in vitro activity of CLA in eradicating MRSP biofilm formation on various materials.Results: Quantitative assay results (P = 0.5126) suggest that CLA does not eradicate MRSP biofilm formation on polystyrene after 4 - 24 h growth periods. Scanning electron micrographs confirmed that CLA did not eradicate MRSP biofilm formed on orthopaedic implants.Conclusions: By determining the in vitro characteristics and activities of MRSP isolates alone and against antibiotics, in vitro models of biofilm related infections can be made. In vitro data suggests that CLA does not effectively eradicate S. pseudintermedius biofilms in therapeutic doses

In vitro activity of antimicrobials alone and in combination therapy against methicillin-resistant Staphylococcus pseudintermedius biofilm formation

Biofilms are defined as complex, surface-attached communities of microorganisms, the formation of which allows bacteria to become recalcitrant to antibiotic therapy and host immune response. Surgical site infections (SSIs) caused by biofilm formation on medical devices have a tremendous impact on the management of patient health in veterinary medicine often leading to morbidity, prolonged hospitalization, and increased treatment costs. Currently, methicillin-resistant Staphylococcus pseudintermedius (MRSP) has emerged as the leading cause of SSIs in canines in veterinary hospitals across North America. Because of the importance of SSIs in companion animals and the increasing evidence that biofilms play a key role in hospital-acquired infections, ways to prevent or eliminate biofilm formation are needed. To test the efficacy of therapeutic eradication treatments of chosen antimicrobials, crystal violet assays had 20 MRSP isolates subcultured and inoculated into a broth dilution before addition to microtiter plates. Absorbance readings, OD570, were then taken after removal of planktonic bacteria followed by staining, heat fixing, and finally with elution of biofilm-embedded bacteria. Quantitative assay results (P = 0.512) suggest that the influence of clarithromycin in the remediation of MRSP biofilm formation was insignificant between 4 and 24 h time points, indicating that MRSP biofilms exhibit higher resistance to clarithromycin in therapeutic doses than other staphylococci. Adhesion was characterized through growth of MRSP isolates on stainless-steel orthopaedic screws exposed to antimicrobials at various time points using Scanning Electron microscopy (SEM). Qualitative analysis of SEM images revealed the ability of the MRSP isolate to form biofilm across the surface of the orthopaedic screws and in-between threads treated with Clarithromycin. Disk diffusion and microtiter plate assay studies along with Scanning Electron Imaging investigations reveals that Clartithromycin does not inhibit MRSP adherence and biofilm formation