Virtual environment in control and programming system for reconfigurable machining robot

Robotski obradni sustavi imaju značajnu ulogu u modernoj proizvodnji. Radom se predlaže primjena virtualnih robota za off-line programiranje. Prikazan je rekonfigurabilni robot za obradu, programiran u G-kôdu, koji se može izravno koristiti od strane programera i operatora CNC alatnih strojeva. Predmet istraživanja su petoosni i šestoosni roboti vertikalne zglobne konfiguracije koji mogu biti konfigurirani tako da emuliraju alatne strojeve s petoosnim vertikalnim i horizontalnim gibanjem glavnog vretena. Razmatrani obradni sustavi su podržani ekvivalentnim virtualnim robotima u CAD/CAM okruženju i sustavu upravljanja. U cilju demonstracije učinkovitosti predložene arhitekture, obrađeno je nekoliko probnih izradaka.Robotic machining systems play an important role in modern manufacturing. The paper proposes the application of virtual robots for off-line programming. The reconfigurable machining robot, programmed in G-code, which can be directly used by CNC machine tool programmers and operators, is presented. The subject of study are 5- and 6-DOF vertical articulated robots that can be configured to emulate vertical and horizontal 5-axis spindle tilting machine tools. The considered machining systems are supported by equivalent virtual robots in the CAD/CAM environment and control system. Several test workpieces were machined to demonstrate the effectiveness of the proposed architecture

Dynamics and control of a spatial disorientation trainer

Abstract Modern combat aircraft can fly at unusual orientations. The spatial disorientation trainer (SDT) examines a pilot's ability to recognise these orientations, to adapt to unusual positions and to persuade the pilot to believe in the aircraft instruments for orientation and not in his own senses. The SDT is designed as a four-degree-of-freedom (4DoF) manipulator with rotational axes. Through rotations about these axes, different orientations can be achieved; different acceleration forces acting on the pilot can also be simulated. In this paper, a control algorithm of an SDT that improves the quality and safety of the SDT motion while improving position accuracy and reducing servo errors is proposed. This control algorithm uses approximate inverse dynamics based on the recursive Newton–Euler algorithm, which accounts for the motors present in the system; it calculates motor torques, as well as the forces and moments acting on the SDT links based on the achievable velocities and accelerations of the robot links. This algorithm enables accurate dimensioning of the axes bearings and links as well. The maximum possible accelerations of the SDT links are calculated in each interpolation period based on the total moments of inertia for the axes of rotation of these links, mutual influences of the link accelerations on each other, and motor capabilities. The forces, moments and torques that act on the SDT links obtained with the suggested algorithm have lower magnitude and smoother profile. In this study, the forces and angular velocities that act on the simulator pilot in the SDT are calculated along with the roll and pitch angles of the gondola for these forces

Patient-provider discordance between global assessments of disease activity in rheumatoid arthritis: a comprehensive clinical evaluation

Abstract Background Discordance between patients with rheumatoid arthritis (RA) and their rheumatology health care providers is a common and important problem. The objective of this study was to perform a comprehensive clinical evaluation of patient-provider discordance in RA. Methods A cross-sectional observational study was conducted of consecutive RA patients in a regional practice with an absolute difference of ≥ 25 points between patient and provider global assessments (possible points, 0–100). Data were collected for disease activity measures, clinical characteristics, comorbidities, and medications. In a prospective substudy, participants completed patient-reported outcome measures and underwent ultrasonographic assessment of synovial inflammation. Differences between the discordant and concordant groups were tested using χ2 and rank sum tests. Multivariable logistic regression was used to develop a clinical model of discordance. Results Patient-provider discordance affected 114 (32.5%) of 350 consecutive patients. Of the total population, 103 patients (29.5%) rated disease activity higher than their providers (i.e., ‘positive’ discordance); only 11 (3.1%) rated disease activity lower than their providers and were excluded from further analysis. Positive discordance correlated with negative rheumatoid factor and anticyclic citrullinated peptide antibodies, lack of joint erosions, presence of comorbid fibromyalgia or depression, and use of opioids, antidepressants, or anxiolytics, or fibromyalgia medications. In the prospective study, the group with positive discordance was distinguished by higher pain intensity, neuropathic type pain, chronic widespread pain and associated polysymptomatic distress, and limited functional health status. Depression was found to be an important mediator of positive discordance in low disease activity whereas the widespread pain index was an important mediator of positive discordance in moderate-to-high disease activity states. Ultrasonography scores did not reveal significant differences in synovial inflammation between discordant and concordant groups. Conclusions The findings provide a deeper understanding of patient-provider discordance than previously known. New insights from this study include the evidence that positive discordance is not associated with unrecognized joint inflammation by ultrasonography and that depression and fibromyalgia appear to play distinct roles in determining positive discordance. Further work is necessary to develop a comprehensive framework for patient-centered evaluation and management of RA and associated comorbidities in patients in the scenario of patient-provider discordance