A method for the assessment and compensation of positioning errors in industrial robots

Industrial Robots (IR) are currently employed in several production areas as they enable flexible automation and high productivity on a wide range of operations. The IR low positioning performance, however, has limited their use in high precision applications, namely where positioning errors assume importance for the process and directly affect the quality of the final products. Common approaches to increase the IR accuracy rely on empirical relations which are valid for a single IR model. Also, existing works show no uniformity regarding the experimental procedures followed during the IR performance assessment and identification phases. With the aim to overcome these restrictions and further extend the IR usability, this paper presents a general method for the evaluation of IR pose and path accuracy, primarily focusing on instrumentation and testing procedures. After a detailed description of the experimental campaign carried out on a KUKA KR210 R2700 Prime robot under different operating conditions (speed, payload and temperature state), a novel online compensation approach is presented and validated. The position corrections are processed with an industrial PC by means of a purposely developed application which receives as input the position feedback from a laser tracker. Experiments conducted on straight paths confirmed the validity of the proposed approach, which allows remarkable reductions (in the order of 90%) of the orthogonal deviations and in-line errors during the robot movements

Virtual Prototyping of a Flexure-based RCC Device for Automated Assembly

The actual use of Industrial Robots (IR) for assembly systems requires the exertion of suitable strategies allowing to overcome shortcomings about IR poor precision and repeatability. In this paper, the practical issues that emerge during common \ue2\u80\u9cpeg-in-hole\ue2\u80\u9d assembly procedures are discussed. In particular, the use of passive Remote Center of Compliance (RCC) devices, capable of compensating the IR non-optimal performance in terms of repeatability, is investigated. The focus of the paper is the design and simulation of a flexure-based RCC that allows the prevention of jamming, due to possible positioning inaccuracies during peg insertion. The proposed RCC architecture comprises a set of flexural hinges, whose behavior is simulated via a CAE tool that provides built-in functions for modelling the motion of compliant members. For given friction coefficients of the contact surfaces, these numerical simulations allow to determine the maximum lateral and angular misalignments effectively manageable by the RCC device

Ectonucleoside triphosphate diphosphohydrolase-1/CD39 affects the response to ADP of female rat platelets

There is evidence that an imbalance of extracellular purine levels may be associated with increased cardiovascular risk. Platelets play a pivotal role in vascular homeostasis and thrombosis and are important source of purine nucleotides and nucleosides. Hydrolysis of nucleotides ATP and ADP is regulated by two ectonucleotidases, triphosphate diphosphohydrolase-1 (NTPDase-1/CD39) and ecto-5’-nucleotidase (ecto-5’-NT/CD73). CD39 enzyme is expressed on the endothelium, circulating blood cells, and smooth muscle cells; there is evidence that changes in CD39 expression and activity affects the potential thrombogenic of a tissue. Gender difference in the cardiovascular risk has been extensively observed; however, while the age-dependent difference in the prevalence of cardiovascular events between men and women has been attributed to the loss of the protective effect of estrogens in the postmenopausal period, the physiological mechanism behind gender disparity is still unclear. Here, we evaluated comparatively male and female rat platelet reactivity and considered the possible role of CD39 at the basis of difference observed. We found a reduced in vitro response to ADP (1–30 µM) of female compared to male platelets, associated to increased platelet CD39 expression and activity. Platelet response to ADP was strongly increased by incubation (10 min) with the CD39 inhibitor, ARL67156 (100 µM), while male platelet response was unaffected. Rat treatment with clopidogrel (30 mg/kg, per os) inhibited ex vivo platelet aggregation. Bleeding time was prolonged in female compared to male. Taken together, our results suggest that platelet ATPase and ADPase activity might be a reliable predictor of platelet reactivity

Exploring the Adoption of UX-Driven Approaches to Design Industrial PLC User Interfaces

Modern automated production systems (e.g., automatic machines, assembly lines, robotic cells) are typically governed by dedicated industrial controllers, such as Programmable Logic Controllers (PLCs), which supervise and coordinate the process by exchanging I/O data, sequencing tasks or triggering actions with the involved automation modules. Different solutions have been developed to offer an intuitive Human-Machine Interface (HMI) programming to the user, based on PLC HMI editors, according to vendor-specific programming languages. However, in the current industrial practice, user interfaces (UIs) are usually generated by software specialists and far from adopting any user-centered approach. As a result, the generated UIs are poorly usable and hard to understand for end users (e.g., operators), diverging from Industry 5.0 ideas that put humans at the center of the modern factory design. In this context, the present paper aims at exploring how the adoption of User eXperience (UX) driven approaches can benefit the design of industrial PLC UIs, reflecting on advantages and limits, and transdisciplinary perspectives. A case study utilizing Beckhoff TwinCAT as PLC environment and Adobe XD as UX design tool is examined and discussed

A review of geometry representation and processing methods for cartesian and multiaxial robot-based additive manufacturing

Nowadays, robot-based additive manufacturing (RBAM) is emerging as a potential solution to increase manufacturing flexibility. Such technology allows to change the orientation of the material deposition unit during printing, making it possible to fabricate complex parts with optimized material distribution. In this context, the representation of parts geometries and their subsequent processing become aspects of primary importance. In particular, part orientation, multiaxial deposition, slicing, and infill strategies must be properly evaluated so as to obtain satisfactory outputs and avoid printing failures. Some advanced features can be found in commercial slicing software (e.g., adaptive slicing, advanced path strategies, and non-planar slicing), although the procedure may result excessively constrained due to the limited number of available options. Several approaches and algorithms have been proposed for each phase and their combination must be determined accurately to achieve the best results. This paper reviews the state-of-the-art works addressing the primary methods for the representation of geometries and the subsequent geometry processing for RBAM. For each category, tools and software found in the literature and commercially available are discussed. Comparison tables are then reported to assist in the selection of the most appropriate approaches. The presented review can be helpful for designers, researchers and practitioners to identify possible future directions and open issues

Path Approximation Strategies for Robot Manufacturing: A Preliminary Experimental Evaluation

Industrial Robots (IRs) are increasingly adopted for material subtraction or deposition functions owing to their advantages over machine tools, like cost-effectiveness and versatility. Unfortunately, the development of efficient robot manufacturing processes still faces unsolved issues related to the IRs poor positioning accuracy and to the tool path generation process. Novel engineering methods and tools are needed for CAD based programming of accurate paths and continuous robot motions to obtain the required manufacturing quality and tolerances. Within this context, to achieve smoothness along the tool path formed by linear G-code segments, the IR controllers’ approximation strategies, summarily reported in the manufacturer’s manuals, must be considered. The aim of this paper is to present the preliminary work carried out to identify the approximation algorithms of a Kuka IR when executing linear moves. An experimental study is conducted by varying the controller settings and the maximum translational velocity. The robot behavior has been acquired thanks to the controller tracing function and then processed to yield relations readily employable for the interpretation of G-Code commands and the subsequent generation of proper robot motion instructions. The obtained formulas allow to accurately predict the robot geometric path and kinematics within the corner transition between two linear segments

Ena/VASP Enabled is a highly processive actin polymerase tailored to self-assemble parallel-bundled F-actin networks with Fascin

Enabled/vasodilator-stimulated phosphoprotein (Ena/VASP) proteins are required for the formation and maintenance of filopodia, finger-like projections at the leading edge of migrating cells that are composed of parallel actin filaments bundled by Fascin. We imaged individual fluorescently labeled Drosophila Ena molecules on both single and Fascin-bundled actin filaments in vitro. Ena stimulates actin assembly by remaining continuously associated with the barbed end and increasing the elongation rate by approximately two- to threefold. Remarkably, the frequency and length of Ena’s processive runs are enhanced on filaments within a Fascin bundle, which drives a positive feedback cycle that allows the assembly of uniformly thick filopodia-like F-actin bundles composed of multiple filaments with aligned ends

A literature review on surgery for cervical vagal schwannomas

Cervical vagal schwannoma is a benign, slow-growing mass, often asymptomatic, with a very low lifetime risk of malignant transformation in general population, but diagnosis is still a challenge. Surgical resection is the treatment of choice even if its close relationship with nerve fibres, from which it arises, threats vagal nerve preservation. We present a case report and a systematic review of literature. All studies on surgical resection of cervical vagal schwannoma have been reviewed. Papers matching the inclusion criteria (topic on surgical removal of cervical vagal schwannoma, English language, full text available) were selected. Fifty-three patients with vagal neck schwannoma submitted to surgery were identified among 22 studies selected. Female/male ratio was 1.5 and median age 44 years. Median diameter was 5 cm (range 2 to 10). Most schwannoma were asymptomatic (68.2%) and received an intracapsular excision (64.9%). Postoperative symptoms were reported in 22.6% of patients. Cervical vagal schwannoma is a benign pathology requiring surgical excision, but frequently postoperative complications can affect patients lifelong, so, surgical indications should be based carefully on the balance between risks and benefits

Carboplatin plus paclitaxel in extensive small cell lung cancer: a multicentre phase 2 study

A multicentre phase 2 trial (single-stage design) was undertaken to test the efficacy and toxicity of carboplatin (AUC 6 according to Calvert) plus paclitaxel (175 mg/m23-h infusion) every 4 weeks in the first line treatment of patients affected by extensive small cell lung cancer. The primary end-point of the trial was the objective response rate. 31 objective responses among 50 patients were considered necessary to proceed to a phase 3 trial. 48 patients were enrolled (median age 59 years). Treatment was very well tolerated. 3 patients (6.2%) had a complete response and 23 (47.9%) a partial response, for an overall response rate of 54.2% (95% CI: 39.2–68.6) Median time to progression was 5.7 months (95% CI: 5.2–6.2). Median survival was 9.6 months (95% CI: 7.2–14.6), with a median follow-up time of alive patients of 12 months. At 1 year, the probability of being progression-free or alive was 0.16 and 0.43, respectively. In conclusion, carboplatin plus paclitaxel as given in the present study is very well tolerated but not sufficiently active to warrant phase 3 comparison with standard chemotherapy regimens. © 2001 Cancer Research Campaign http://www.bjcancer.co

Quality of life, compliance, safety and effectiveness in fit older metastatic colorectal patients with cancer treated in first-line with chemotherapy plus cetuximab: A restrospective analysis from the ObservEr study

Abstract Objectives The influence of age ( KRAS wild type (WT) metastatic colorectal cancer (mCRC). Methods 225 patients of the Observed study (PS 0-1) were retrieved based on age ( Results The two patient groups (141  p  = 0.002), which is likely due to higher proportions of metastatic resection (27.0% vs 8.3%; p  = 0.001) and utilization of second-line therapy in younger group (58.9% vs 42.9%; p  = 0.028). Conclusion The current data suggest that fit older patients with mCRC can be safely treated with a cetuximab-based therapy, as QoL and safety profile do not seem to be affected by age. In addition, age did not impact the choice of chemotherapy to be associated to cetuximab and treatment compliance