Longitudinal Rotation Research Articles

Visualization Of Nanoparticle Orientation Structures Inside Complex Fluids Using Polarized Light Imaging Technique

The present paper reports on the effect of 3D-oriented particles on birefringence using the concept of 'rheooptics', a technique for identifying changes in the internal structure or flow dynamics of complex fluids from changes in optical anisotropy (birefringence). We used the photoelastic method, as a kind of polarized light imaging technique, to visualize the internal orientation structure induced by applying shear stress to cellulose nanocrystal (CNC) suspensions under shear flow. Two different rheometers (concentric cylinder and parallel plate-type) that can easily combine a birefringence measurement system were introduced to Transverse rotation Longitudinal rotation perform the shear flow induction, and the birefringence was measured and compared from vertical and horizontal directions for shear. The birefringence measurements from different directions provide an opportunity to investigate the effect of 3D-oriented CNCs on birefringence, which is a novelty of the present study. The measured birefringence was fitted with the empirical equation proposed in the previous study and followed the power law of applied shear rate with the same exponent, independent of the shear direction at the time of measurement This result suggests that there is a common physical background that gives birefringence a power law. This exponent was different from the values given in previous studies and is explained by differences in the particle interaction behaviour based on the concentration of suspensions and CNC length. Note that the proportionality coefficients differ by a factor of 10, clearly indicating differences due to the direction of birefringence measurement. These results indicate that birefringence due to transverse rotation of the CNC is more sensitive to shear stress than to longitudinal rotation.

Region-specific Effects of Transcranial Direct Current Stimulation Over Posterior Parietal Cortex and Cerebellum on Standing Postural Displacement After Prism Adaptation

Prism adaptation (PA) induces the after-effects of adapted tasks and transfers after-effects of non-adapted tasks, in which PA with pointing movements transfers to postural displacement during eyes-closed standing. However, the neural mechanisms underlying the transfer of PA after-effects on standing postural displacement remain unclear. The present study investigated the region-specific effects of transcranial direct current stimulation (tDCS) over the posterior parietal cortex (PPC) and cerebellum during prism exposure (PE) on standing postural displacement in healthy adults. Forty-two healthy young adults were grouped into pointing during PE with cathodal tDCS over the right PPC, anodal tDCS over the right cerebellum, and sham tDCS groups. They received 20 min of tDCS, during which they pointed to the visual targets while wearing prism lenses with a leftward visual shift (30 diopters) for 15 min. During the early PE, the pointing errors in the cerebellum group were significantly displaced more accurately toward the targets than those in the PPC group. However, after leftward PE, all groups had similar rightward displacements of the straight-ahead pointing with eyes closed. The PPC group only exhibited significant rightward center-of-pressure displacement during eyes-closed standing with feet-closed after leftward PE. The perception of longitudinal body axis rotation, as an indicator of the subjective body vertical axis, did not differ significantly between the pre- and post-evaluations in all groups. These results show that the PPC during PE could make an important neural contribution to inducing transfer of PA after-effect on standing postural displacement.

Inferring the Interstellar Magnetic Field Direction from Energetic Neutral Atom Observations of the Heliotail

Determining the magnitude and direction of the interstellar magnetic field (B ISM) is a long-standing problem. To date, some methods to infer the direction and magnitude have utilized best-fit models to the positions of the termination shock and heliopause measured by Voyager 1 and 2. Other models use the circularity of the Interstellar Boundary Explorer (IBEX) ribbon assuming a secondary energetic neutral atom (ENA) mechanism. Previous studies have revealed that the B ISM organizes the orientation of the heliotail with respect to the solar meridian. Here we propose a new way to infer the direction of the B ISM based on ENA observations of the heliotail. IBEX observations of the heliotail have revealed high-latitude lobes of enhanced ENA flux at energies >2 keV. Analyses showed that the high-latitude lobes are nearly aligned with the solar meridian, while also exhibiting a rotation with solar cycle. We show, using steady-state solar wind conditions, that the inclination of the lobes reproduced with commonly used values for the angle (α BV ) between B ISM and the interstellar flow in the hydrogen deflection plane (40° < α BV < 60°) is inconsistent with the IBEX ENA observations. We report that 0° < α BV < 20° best replicates the heliotail lobe inclinations observed by IBEX. Additionally, our model results indicate that the variation of the solar magnetic field magnitude with solar cycle causes the longitudinal rotation of the lobes observed by IBEX by affecting the inclination of the lobes.

How spotting technique affects dizziness and postural stability after full-body rotations in dancers

Consecutive longitudinal axis rotations are very common in dance, ranging from head spins in break dance to pirouettes in ballet. They pose a rather formidable perceptuomotor challenge – and hence form an interesting window into human motor behaviour – yet they have been scarcely studied. In the present study, we investigated dancers' dizziness and postural stability after consecutive rotations. Rotations were performed actively or undergone passively, either with or without the use of a spotting technique in such an order that all 24 ordering options were offered at least once and not more than twice.Thirty-four dancers trained in ballet and/or contemporary dance (aged 27.2 ± 5.1 years) with a mean dance experience of 14.2 ± 7.1 years actively performed 14 revolutions in passé or coupé positions with a short gesture leg “foot down” after each revolution. In addition, they were passively turned through 14 revolutions on a motor-driven rotating chair. Participants' centre-of-pressure (COP) displacement was measured on a force-plate before and after the rotations. Moreover, the dancers indicated their subjective feeling of dizziness on a scale from 0 to 20 directly after the rotations. Both the active and passive conditions were completed with and without the dancers spotting.As expected, dizziness was worse after rotations without the adoption of the spotting technique, both in active and passive rotations. However, the pre-post difference in COP area after active rotations was unaffected by spotting, whereas in the passive condition, spotting diminished this difference. Our results thus suggest that adopting the spotting technique is a useful tool for dizziness reduction in dancers who have to perform multiple rotations. Moreover, spotting appears most beneficial for postural stability when it involves less postural control challenges, such as when seated on a chair and occurs in situations with limited somatosensory feedback (e.g., from the cutaneous receptors in the feet). However, the unexpected finding that spotting did not help postural stability after active rotations needs to be investigated further in future studies, for example with a detailed analysis of whole-body kinematics and eye-tracking.

Motion planning and control of planar serial chain articulating locomotion system

This paper addresses two important problems in motion planning and control of serial chain planar articulating locomotion systems moving on a flat surface. Locomotion systems generally use closed curve cyclic gaits to perform maneuvers in the environment. The geometric mechanics tools are used to identify the cyclic gaits. Firstly, a motion control approach is presented using a single cyclic gait parametrized with variable gait parameters. The parameterized gait is used to drive the system along a continuous trajectory with varying curvature. On the other hand, the proposed approach presents how the gait parameters can be controlled to smoothly track a continuous trajectory. Secondly, this paper presents a joint coordination approach to generalize the height function based approach to design cyclic gaits for the system having joint space with more than two degrees of freedom. Using joint coordination approach, cyclic gaits can be designed for different motion behaviors such as longitudinal motion, sideways motion and rotation in place. The joint coordination approach also helps generalizing the proposed motion control approach to planar serial chain articulating robots with any even number of joints.

Discrete element simulation of vibration compaction of slag subgrade

In this study, to improve the compaction quality and parameters of slag, discrete element models of irregular rock particles (10–60 mm) and circular soil particles (5 mm) were established based on on-site slag screening results. The motion of the vibratory roller was captured by coupling the roadbed model with the roller model in a simulation in which the roller vibrated and compacted the slag subgrade. The results indicated that (1) the best compaction was achieved when the small particle content was 40%, the medium particle content was 20%, and the large particle content was 40%. (2) When the slag was dominated by small rock particles, the optimum compaction frequency was 28 Hz, and when large rock particles dominated, the optimum compaction frequency was 33 Hz. (3) Rock particles were the primary particles that experienced stress in the vibration compaction, and the compressive force and displacement depended on the particle size. (4) The longitudinal and vertical displacements and rotation angles of the soil and rock particles were examined. The results of this study are conducive for advancing the understanding of slag compaction and improving the working efficiency and compaction quality of rollers.

Cardiac Mechanics and Valvular and Vascular Abnormalities in Hypereosinophilic Syndrome.

Hypereosinophilic syndrome (HES) is considered to be a rare myeloproliferative disease that is characterized by persistent eosinophilia with associated multiple-organ damage. The heart is often involved in HES, representing a major cause of morbidity and mortality. HES is a heterogeneous group of disorders; the majority of the cases are idiopathic. Summarizing the findings regarding myocardial, valvular, and vascular abnormalities in a series of patients with HES, most studies found normal left ventricular (LV) volumes with reduced LV global longitudinal strain and LV apical rotation and twist in HES cases, accompanied by increased left atrial (LA) volumes and stroke volumes, reduced peak LA circumferential strain (representing systolic abnormalities), and mitral annular dilation and functional deterioration. Regarding the right heart, preserved right ventricular volumes and functional properties, increased right atrial volumes, mild RA functional abnormalities, and dilated tricuspid annular dimensions without functional impairment could be seen in these studies. Aortic and pulmonary valves showed no specific disease-related alterations. Vascular abnormalities included increased aortic stiffness without dilation of the aorta and pulmonary hypertension in some cases. These results suggest disease-specific but relatively mild myocardial, valvular, and vascular abnormalities in HES. The present review aimed to summarize the available clinical data about cardiac mechanics and valvular and vascular abnormalities in a series of patients with HES.

An Atypical Presentation of Hip Dislocation In A Pregnant Patient: A Case Report and Review of the Literature

Managing an injured patient who is pregnant can be difficult in the management and investigation of the case especially when the patient presents atypically. We encountered a 25-year-old female patient who sustained a posterior dislocation of the right hip and was pregnant at 12 weeks gestation following a road traffic accident. The patient presented to OPD with an atypical attitude of limb i.e., both hip and knee in flexion without any internal rotation and adduction of the limb following which MRI was done which showed right hip posterior dislocation. Through an interdepartmental, skilful team approach the patient, after taking the obstetrician’s opinion and the patient under short GA, Closed reduction by Rochester method (longitudinal traction and rotation control) was done for the right hip joint without any complication. As pregnant females possess more risk and complication and more challenges are expected in management, Orthopaedic surgeons are well equipped to treat such patients to reduce patient morbidity and mortality resulting in better outcomes. Keywords Posterior dislocation of hip, Pregnant female, Atypical presentation, Closed reduction

Exploring the impact of longitudinal modulation on the twisting angle in Pancharatnam-Berry phase-based waveguides.

A circularly polarized (CP) beam propagating in a rotated anisotropic material acquires an additional phase delay proportional to the local rotation angle. This phase delay is a particular kind of geometric phase, the Pancharatnam-Berry phase (PBP), stemming from the path of the beam polarization on the Poincaré sphere. A transverse gradient in the geometric phase can thus be imparted by inhomogeneous rotation of the material, with no transverse gradient in the dynamic phase. A waveguide based upon this principle can be induced when the gradient accumulates in propagation, the latter requiring a longitudinal rotation in the optic axis synchronized with the natural rotation of the light polarization. Here, we evaluate numerically and theoretically the robustness of PBP-based waveguides, in the presence of a mismatch between the birefringence length and the external modulation. We find that the mismatch affects mainly the polarization of the quasi-mode, while the confinement is only slightly perturbed.

Numerical simulation on seismic pounding damage in a simply-supported steel bridge

Steel bridges are generally considered to perform well during seismic activity. Nevertheless, they still suffered much unexpected seismic damage in the Kumamoto earthquake, especially seismic pounding damage. Previous studies on bridge pounding damage have generally focused on reinforced concrete bridges. However, steel bridges' dynamic characteristics are more complex, the stiffness of each component varies significantly, and relevant research remains limited. Therefore, the numerical simulation method is adopted in this paper to study the pounding damage of simple-supported steel bridges under seismic events in detail. The multiscale, fine three-dimensional finite element model was built using the general finite element calculation platform Abaqus, and dynamic implicit analysis was performed. Numerical results show that large and near-fault seismic activity results in obvious pounding damage to steel beams. Specifically, longitudinal pounding causes damage to the steel beam's ends; however, the damage is typically localized and mild. Lateral pounding further causes direct damage to the steel beams, resulting in extensive and serious damage. Horizontal pounding which combines longitudinal and lateral causes rotation of the bridge deck and aggravates the lateral damage to steel beams. In addition, a pounding identification method based only on displacement data is proposed, and a feasible preventive measure for lateral pounding damage is suggested.

The Value of the Pediatric Urgent Care in Pediatric Resident Education.

Pediatric urgent care (UC) is a growing field and may provide unique learning opportunities for pediatric residents. We aimed to assess whether a UC rotation could be feasible and meaningful and help fill educational gaps. Within our current X+Y rotational model, we used Kern's 6-step approach for curriculum development to create a longitudinal UC educational experience for postgraduate year 2 (PGY2) pediatric residents. We assessed progress towardachieving our aim by using a mixed-methods approach matched to Kirkpatrick's levels of learning, including program annual evaluations, self-assessed UC competencies, and 360 milestone evaluations. A total of 14 PGY2s participated in our yearlong longitudinal rotation without duty hour violations or deviations from well childcare. Thematic analysis revealed concepts of autonomy, procedural access, and intentionality of education. Residents showed statistical improvement in 4/10 milestones and 26/27 self-assessed performance items. Of 14 residents, 6 scored ≥4 on all milestones by the end of the year. Our curriculum demonstrates a valuable role for the pediatric UC in the procedural and clinical education of pediatric residents. Practical implications and assessment tools of such a curriculum may be valuable for others interested in integrating this learning experience into their current educational model.

Relationship between Longitudinal Upper Body Rotation and Energy Cost of Running in Junior Elite Long-Distance Runners.

Running is a basic form of human locomotion and one of the most popular sports worldwide. While the leg biomechanics of running have been studied extensively, few studies have focused on upper-body movement. However, an effective arm swing and longitudinal rotation of the shoulders play an important role in running efficiency as they must compensate for the longitudinal torques generated by the legs. The aim of this study is to assess the upper-body rotation using wearable inertial sensors and to elucidate its relation to energy expenditure. Eighty-six junior elite middle- and long-distance runners (37 female, 49 male) performed an incremental treadmill test with sensors attached on both shoulders, tibiae and the sacrum. The mean and total horizontal shoulder and pelvis rotations per stride were derived while energy costs were determined using respiratory gas analysis and blood sampling. Results show that shoulder and pelvis rotations increase with running speed. While shoulder rotation is more pronounced in female than in male runners, there is no sex difference for pelvis rotation. The energy cost of running and upper trunk rotation prove to be slightly negatively correlated. In conclusion, upper body rotation appears to be an individual characteristic influenced by a sex-specific body mass distribution.

Research of features of oscillating process’ behavior in the nonlinear system of individual traction drive of an electrobus

BACKGROUND: When a vehicle is in motion, self-oscillations which properties are dependent on slip rate in a contact patch may occur in the area of tire interaction with ground surface. Oscillations frequency will vary in dependence with value of wheel slip relative to ground surface. Soft self-oscillations are excited by variable set of initial conditions at full slip in traction and driven wheel rolling modes as well as in mixed braking mode with partial slip. Hard mode of self-oscillations occurs at full wheel slip in braking mode. These processes have a negative impact on the processes in electric drive and mechanical drivetrain reducing their efficiency and may cause damage of components. Oscillations in the system are excited by interaction forces of an elastic tire with ground surface featuring vertical oscillations due to elastic behavior of its interaction with road unevenness. AIMS: Research of features of oscillating process behavior in the nonlinear system of individual traction drive of an electrobus. METHODS: Simulation of self-oscillation excitation processes in the area of contact interaction of a wheel and road was carried out in the MATLAB/Simulink software package. RESULTS: The article features the results of simulation and experimental studies of self-oscillation excitation processes of the KAMAZ 6282 electrobus moving on asphalt-concrete surface. It was found that vertical wheel displacement when moving through unevenness lead to oscillating behavior of vertical reaction forces in contact patches and, as a consequence, to oscillating behavior of longitudinal reaction forces, torque and rotation velocity of the shaft of the traction electric motor of the individual drive. It was defined that tire oscillation frequency is 67 Hz that coincides with electric motor shaft rotation oscillation frequency and this value is the same for both experiment and simulation. CONCLUSIONS: Practical value of the study lies in ability of using the study results at development of self-oscillation processes exclusion algorithms as a part of vehicle control system.

Genetics, patterns of hypertrophy and fibrosis on myocardial mechanics in hypertrophic cardiomyopathy

Abstract Funding Acknowledgements Type of funding sources: None. Background Asymmetrical hypertrophy, myocyte disarray and fibrosis due to genetic cause are underlying pathology of hypertrophic cardiomyopathy (HCM). However, their contribution to myocardial functional mechanics are not extensively evaluated yet. Purpose In this study, we sought to investigate effects of genetic mutation, patterns of ventricular hypertrophy and fibrosis on myocardial mechanics in HCM. Methods In 133 patients with HCM, chamber geometry, segmental late gadolinium enhancement (LGE), extracellular volume fraction (ECV) by cardiac magnetic resonance imaging (CMR), echo-derived diastolic function analyses and genetic test were performed. Left ventricular (LV) segmental and global longitudinal strain (LS), circumferential strain (CS), and rotation were measured by feature tracking analysis of CMR. Results Patients with sarcomere gene mutation (SM) had lower LV-CS (global and all three slices) along with higher prevalence of midwall type LGE, LGE amount and ECV. Despite global LS was not lower in SM, anteroseptal-LS was significantly impaired accompanying with higher septal wall thickness. To compensate impaired anteroseptal LS, basal endocardial rotation was paradoxically increased in SM. Augmented basal segmental was significantly related to obstructive HCM. In apical HCM, although apical segmental LS was significantly lower, higher apical rotation and preserved apical CS along with lower prevalence of SM. The E/e’ was significantly related to LV mass index, LGE extent but not with SM. Conclusion Circumferential myocardial function was significantly reduced in SM independent of fibrosis extent, suggesting primary phenotype. However, longitudinal fiber function was more related to hypertrophy regardless of SM. LV diastolic function was more related to LV mass, extent and degree of fibrosis including non-thickened myocardium regardless of SM.

Modulation instability in nonlinear flexible mechanical metamaterials.

In this paper, we study modulation instabilities (MI) in a one-dimensional chain configuration of a flexible mechanical metamaterial (flexMM). Using the lumped element approach, flexMMs can be modeled by a coupled system of discrete equationsfor the longitudinal displacements and rotations of the rigid mass units. In the long wavelength regime, and applying the multiple-scales method we derive an effective nonlinear Schrödinger equationfor slowly varying envelope rotational waves. We are then able to establish a map of the occurrence of MI to the parameters of the metamaterials and the wave numbers. We also highlight the key role of the rotation-displacement coupling between the two degrees of freedom in the manifestation of MI. All analytical findings are confirmed by numerical simulations of the full discrete and nonlinear lump problem. These results provide interesting design guidelines for nonlinear metamaterials offering either stability to high amplitude waves, or conversely being good candidates to observe instabilities.

Left Ventricular "Longitudinal Rotation" and Conduction Abnormalities-A New Outlook on Dyssynchrony.

The complete left bundle branch block (CLBBB) results in ventricular dyssynchrony and a reduction in systolic and diastolic efficiency. We noticed a distinct clockwise rotation of the left ventricle (LV) in patients with CLBBB ("longitudinal rotation"). The aim of this study was to quantify the "longitudinal rotation" of the LV in patients with CLBBB in comparison to patients with normal conduction or complete right bundle branch block (CRBBB). Sixty consecutive patients with normal QRS, CRBBB, or CLBBB were included. Stored raw data DICOM 2D apical-4 chambers view images cine clips were analyzed using EchoPac plugin version 203 (GE Vingmed Ultrasound AS, Horten, Norway). In EchoPac-Q-Analysis, 2D strain application was selected. Instead of apical view algorithms, the SAX-MV (short axis-mitral valve level) algorithm was selected for analysis. A closed loop endocardial contour was drawn to initiate the analysis. The "posterior" segment (representing the mitral valve) was excluded before finalizing the analysis. Longitudinal rotation direction, peak angle, and time-to-peak rotation were recorded. All patients with CLBBB (n = 21) had clockwise longitudinal rotation with mean four chamber peak rotation angle of -3.9 ± 2.4°. This rotation is significantly larger than in patients with normal QRS (-1.4 ± 3°, p = 0.005) and CRBBB (0.1 ± 2.2°, p = 0.00001). Clockwise rotation was found to be correlated to QRS duration in patients with the non-RBBB pattern. The angle of rotation was not associated with a lower ejection fraction or the presence of regional wall abnormalities. Significant clockwise longitudinal rotation was found in CLBBB patients compared to normal QRS or CRBBB patients using speckle-tracking echocardiography.

Learning pediatric emergency medicine over time: A realist evaluation of a longitudinal pediatric emergency medicine clinical experience.

Emergency medicine (EM) practitioners must be proficient at caring for patients of all ages, including pediatric patients. Traditionally, EM trainees learn pediatric emergency medicine (PEM) through block rotations. This is problematic due to the seasonal nature of pediatric diseases and infrequent critical events. Spaced repetition learning theory suggests PEM would be better learned through longitudinal rotations. The transition to competency-based medical education (CBME) in Canada is accelerating the need to find novel ways to attain competencies in postgraduate training. At McMaster University, senior EM trainees can choose either traditional PEM blocks or longitudinal rotations. Our objective was to understand how learners experience these different rotations given the transition to CBME in Canada. Using a realist framework of program evaluation, we conducted semistructured interviews with key stakeholders (trainees, program directors, attending physicians) in EM. The realist framework was used to understand how context interacts with theoretical mechanisms to produce outcomes of interest. Data were analyzed using inductive, conventional content analysis. All investigators coded a subset of transcripts independently and in duplicate to achieve intercoder agreement. A total of 13 interviews were completed with trainees (n= 11) and staff physicians (n= 2). The learning experience exists within an educational and clinical context, which are logistically distinct but inseparable. The longitudinal learning experience appears to improve learning through spaced repetition, which prevents atrophy of skills and knowledge while also benefitting from the offsetting of seasonal variability associated with many pediatric diseases. Improved feedback and entrustment are facilitated through the building of coaching relationships over time. Barriers to the learning experience are related mainly to logistical difficulties associated with resolving longitudinal and blocked learning experiences. Improved relationships with the interprofessional team may provide distinct learning opportunities and improved team functioning. Block rotations were identified as more valuable to junior trainees learning fundamental concepts. Longitudinal learning provides numerous advantages to learning PEM, including increased case variety, spaced repetition of core concepts, and a perception of greater entrustment of the learner through formation of coaching relationships over time. Future projects looking to quantify the differences between longitudinal and block learning to objectively show a difference in skills and knowledge are needed.

Study on Top Hierarchy Control Strategy of AEBS over Regenerative Brake and Hydraulic Brake for Hub Motor Drive BEVs

A hub motor is an effective drive system for Battery Electric Vehicles (BEVs). However, due to limitations on packaging and cost, there are few applications in which hub motors are taken as the only actuators for a brake vehicle. Most applications involve a Regenerative Braking System (RBS) combined with a Hydraulic Braking System (HBS). In this paper, a top hierarchy Advanced Emergency Braking System (AEBS) controller is designed in Matlab/Simulink and State-flow, including functionalities of basic emergency braking, brake force distribution between front and rear wheels, anti-lock braking and coordination between RBS and HBS based on Model Predictive Control (MPC); a Seven Degrees of Freedom (DOF) BEV chassis model is constructed and rear-end crash test scenarios are created in Carsim with a high and low road adhesion coefficient. A series of comparison tests show that not only are the stopping distances between the ego vehicle and target vehicle shorter, but also the braking torques, longitudinal slip ratio and rotation speed of each wheel are well controlled without wheel locking. To sum up, in addition to meeting the AEBS requirements of avoiding a rear-end collision, the control strategy developed in this paper also levels up braking performance and enhances vehicle stability on both high-mu and low-mu roads for BEVs driven by a hub motor independently.

Generation of a sub-wavelength sized optical needle with arbitrary longitudinal rotation.

We show that under tight focusing conditions, arbitrarily rotating the longitudinally polarized optical needle in space is possible. Applying the Richards and Wolf vector diffraction methods, the explicit expressions underlying the simultaneous control depth of focus (DoF), intensity suppression of the sidelobes, as well as the orientation of the optical needle can be obtained, and then the strength vectors of the three-dimensional electromagnetic fields can be calculated. Calculations reveal that the sidelobe suppression ratio reaches 5.35% of the principal lobe, the optimal DoF is 5.1λ, and the maximum length is about 18.2λ. In addition, we specify the necessary conditions for rotating the sub-wavelength sized optical needle in the longitudinal field. Such an optical needle with controllable length, purity, and orientation can provide a flexible approach and additional degree of freedom for 3D precise fabrication and some other potential application areas.

Work space analysis of a new instrument for Natural Orifice Transluminal Endoscopic Surgery (NOTES)

Abstract Minimally invasive procedures such as Natural Orifice Transluminal Endoscopic Surgery (NOTES) require powerful, small, and flexible instruments. A cable-driven instrument was developed, which is able to retract tissue to create sufficient space for an actual operation (e.g. cholecystectomy). In this paper, the work space of a developed instrument is presented. The work space is calculated using direct kinematics equations and verified by measurement using an electromagnetic (EM) tracking system. The angular orientation of the instrument can be up to 85° with a length of the active section of 60 mm. However, a longitudinal rotation up to 17° becomes apparent. This is due to the characteristics of the steel cable used for actuation. Nevertheless, the instrument reaches the intended work space. Further measurements are necessary to evaluate the instrument’s behavior under payload and whether this affects the work space.