Kinematic Functionality Research Articles

Digital workflow for a direct restorative procedure using a 4D virtual articulator

The purpose of this case report was to describe a procedure for 4D virtual mounting and how to develope static and dynamic occlusion through diagnostic waxing. A 16-years-old male patient with a recent history of anterior dental trauma presented with the complaint of esthetic and function restoration. The anterior guidance within the occlusal scheme in all anterior restoration should be considered as a relevant aspect as well as esthetics. A fully digital protocol was presented using a virtual articulator through the incorporation of data from 4D optical technology. The restorative therapy was carried out in the following phases: direct digital data collection acquisition, diagnostic waxing on a virtual model, and definitive restoration. The first step was the intraoral scan of both arches before treatment. The static interocclusal record was made in maximal intercuspal position by an Intraoral scanner and the dynamic one by new measuring system “Jaw Motion Analyser Optic System” (JmA (optic System/JMA; Zebris medical, Isny Germany), which aims at a complete digital workflow for the analysis of the occlusal scheme of mutually protected articulation. The 4D concept added a missing link, brought the digital workflow, and introduced patient-specific movements with kinematic digital facebow functionality. Esthetic and function digital waxing was made (Exocad GmbH) and a waxing cast was fabricated by 3D printing in addition a silicone index was produced from it. The direct composite restoration was made intraorally. This study seems to encourage furthermore clinical trials to validate the use of this methodology.

Design and analysis of novel kinematically redundant reconfigurable generalized parallel manipulators

A conventional parallel manipulator (PM) generally employs independent serial kinematic chains to support one rigid moving platform. Compared with PMs, generalized parallel manipulators (GPMs) with configurable platforms can improve the kinematic performance and functionality. This paper highlights the idea of designing and analyzing novel GPMs with configurable platforms. Firstly, the type synthesis of GPMs is performed. Then a novel class of reconfigurable GPMs with remotely operated grippers is constructed. Secondly, the motion-screw system and the reconfiguration property of the manipulator are analyzed based on screw theory. Moreover, the position analysis of the GPM is carried out to evaluate the workspace and reveal the motion characteristics. Furthermore, the numerical examples and simulation results are obtained to demonstrate the presented methodology. The feasible arrangement of the actuated joints is studied and the potential application of the GPM is discussed. Finally, a prototype is manufactured to illustrate the advocated design philosophy and the functionality of the GPM.

Beach Topography Surveying Using Unmanned Aerial Vehicle Photogrammetry Technology

The mechanisms of in situ topography changes must be identified for spatial planning in coastal areas. In this study, the authors used in situ direct measurement methods and indirect remote-sensing technologies to develop a method for beach topography surveillance. Unmanned aerial vehicles (UAVs) have advantages of high portability and mobility and low operating altitude. Therefore, a UAV was equipped with a lightweight camera and a positioning system that comprised a global positioning system and an inertial measurement unit. Aerial photogrammetry and aerial triangu-lation methods were adopted for matching image feature points to obtain the corresponding topographic points in the sand. A virtual base station with real-time kinematic positioning functionality was used to measure the coordinates of the ground control points for correcting the actual coordinates to obtain actual topographic points of the beach sand. The results obtained using image-matching point clouds and direct measurements were compared. The ground sample distance of a UAV at the operational altitude of 70 m was 3.26 cm. Moreover, the average elevation error was 3.20 cm, and the root mean square error was 0.169 m. The measurement error was ±25 cm, which was within the acceptance criteria of±50 cm set by Water Resources Agency, Ministry of Economic Affairs, Taiwan. UAV imaging technology can increase the efficiency of conventional manual sampling and reduce the cost of indirect observations, thus minimizing the measurement errors and field measurement costs.

Multibody Dynamics on Differentiable Manifolds

Abstract Topological and vector space attributes of Euclidean space are consolidated from the mathematical literature and employed to create a differentiable manifold structure for holonomic multibody kinematics and dynamics. Using vector space properties of Euclidean space and multivariable calculus, a local kinematic parameterization is presented that establishes the regular configuration space of a multibody system as a differentiable manifold. Topological properties of Euclidean space show that this manifold is naturally partitioned into disjoint, maximal, path connected, singularity free domains of kinematic and dynamic functionality. Using the manifold parameterization, the d'Alembert variational equations of multibody dynamics yield well-posed ordinary differential equations of motion on these domains, without introducing Lagrange multipliers. Solutions of the differential equations satisfy configuration, velocity, and acceleration constraint equations and the variational equations of dynamics, i.e., multibody kinematics and dynamics are embedded in these ordinary differential equations. Two examples, one planar and one spatial, are treated using the formulation presented. Solutions obtained are shown to satisfy all three forms of kinematic constraint to within specified error tolerances, using fourth-order Runge–Kutta numerical integration methods.

Mechanical design of a low-cost ABS hand prosthesis using the finite element method

Many hand accidents are reported around the world resulting in a necessity to perform a procedure of amputation of the hand. For this consideration, a large number of hand prostheses have been designed. However, the mechanical design of these prostheses present challenges such as kinematic functionality, strength, and cost. The present article analyses the mechanical design of a low-cost practical hand prosthesis using the finite element method with the help of Abaqus commercial software. Functional and technical requirements were considered to consider the biomechanics of the human hand. The hand prosthesis was conferred with 14-degrees-of-freedom (DOF), which gives it the capacity for grips associated with security, stability, dexterity, and sensibility. Additionally, due to practicality and low-cost manufacturing techniques, fused deposition modelling with acrylonitrile butadiene styrene (ABS) is proposed. The evaluation of the hand prosthesis was carried out by tensile, flexural, and torsional load conditions. Finally, the mechanical effectiveness of the designed prosthesis was demonstrated since maximum stresses close to 13 MPa were computed, which are less than the yield stress of ABS.

Pre-disaster mapping with drones: an urban case study in Victoria, British Columbia, Canada

Abstract. We report a case study using drone-based imagery to develop a pre-disaster 3-D map of downtown Victoria, British Columbia, Canada. This represents the first drone mapping mission over an urban area approved by Canada's aviation authority. The goal was to assess the quality of the pre-disaster 3-D data in the context of geospatial accuracy and building representation. The images were acquired with a senseFly eBee Plus fixed-wing drone with real-time kinematic/post-processed kinematic functionality. Results indicate that the spatial accuracies achieved with this drone would allow for sub-meter building collapse detection, but the non-gimbaled camera was insufficient for capturing building facades.

A Low-Cost Soft Robotic Hand Exoskeleton for Use in Therapy of Limited Hand–Motor Function

We present the design and validation of a low-cost, customizable and 3D-printed anthropomorphic soft robotic hand exoskeleton for rehabilitation of hand injuries using remotely administered physical therapy regimens. The design builds upon previous work done on cable actuated exoskeleton designs by implementing the same kinematic functionality, but with the focus shifted to ease of assembly and cost effectiveness as to allow patients and physicians to manufacture and assemble the hardware necessary to implement treatment. The exoskeleton was constructed solely from 3D-printed and widely available off-the-shelf components. Control of the actuators was realized using an Arduino microcontroller, with a custom-designed shield to facilitate ease of wiring. Tests were conducted to verify that the range of motion of the digits and the forces exerted at the fingertip coincided with those of a healthy human hand.

Архитектура тренажерной системы подготовки операторов радиационно стойких манипуляторов

Nowadays Industrial robots of different kinematic structures and functionality are widely used nowadays in different areas of industry and most of them function autonomously with preprogrammed set of actions or typical trajectories. Some special purposes mobile and stationary robots are human-controlled and in most cases require qualified operator skills. For example, in nuclear industry the mechanical and electro-mechanical “master arm – slave arm” manipulators are widely used. Modern approaches of control systems and human machine interfaces designs allow to eliminate direct copy of kinematic configuration of manipulator arms, add semi-automatic and automated control modes. Key feature of such manipulator systems is a presence of human in control loop, by reason of variety and complexity of manipulations and, in some cases, non-deterministic environment. Due to these factors, it is very desirable to form operator sustainable skills to control such manipulators, including learning process using training systems. This article describes general approaches and practical aspects of the operator training and qualification system for arm-based special purpose manipulators. The set of training system functions include: general manipulator control (basic motion) and grasping actions, manipulator operations in restricted working areas, operator actions using virtual reality helms and multi-monitor visualization, etc. The hardware and software architecture of training system should allow effective training process and teamwork of trainee and instructor to reach good results. The paper proposes ROS-based software part of training system with description of inter-process communication messages, data formats, integration with database and following analysis of trainee action.

Robot Manipulator Capability in MATLAB: A Tutorial on Using the Robotics System Toolbox [Tutorial

i»?The Robotics System Toolbox for MATLAB provides a wide and growing set of functionalities for creating robotic systems: Robot Operating System (ROS) integration, mobile robotics, and robot manipulator arms. This capability increases with each release and is targeted at industrial developers as well as academic teaching and research. This tutorial is concerned with the robot manipulator kinematic functionality that has been available since MATLAB release 2016b.

Wide field of view computed tomography and mid carpal instability: The value of the sagittal radius–lunate–capitate axis – Preliminary experience

PurposeDynamic four dimensional (4D) computed tomography (CT) has recently emerged as a practical method for evaluating complex functional abnormality of joints. We retrospectively analysed 4D CT studies undertaken as part of the clinical management of hand and wrist symptoms.We present our initial experience of 4D CT in the assessment of functional abnormalities of the wrist in a group of patients with mid carpal instability (MCI), specifically carpal instability non-dissociative. We aim to highlight unique features in assessment of the radius–lunate–capitate (RLC) axis which allows insight and understanding of abnormalities in function, not just morphology, which may be contributing to symptoms. Materials and methodsWide field of view multi-detector CT scanner (320 slices, 0.5mm detector thickness) was used to acquire bilateral continuous motion assessment in hand flexion and extension. A maximum z-axis coverage of 16cm was available for each acquisition, and a large field of view (FOV) was used. Due to the volume acquisition during motion, reconstructions at multiple time points were undertaken. Dynamic and anatomically targeted multi-planar-reconstructions (MPRs) were then used to establish the kinematic functionality of the joint. ResultsOur initial cohort of 20 patients was reviewed. Three findings were identified which were present either in isolation or in combination. These are vacuum phenomenon, triggering of the lunate and capitate subluxation. We provide 4D CT representations of each and highlight features considered of clinical importance and their significance. We also briefly discuss how the current classifications of dynamic wrist abnormalities may alter with the supplementary information provided by dynamic 4D CT MSK acquisitions. Conclusion4D CT has provided a unique insight into motion disorders. We highlight our early experience with the ability of 4D CT to investigate the RLC axis and three signs which have provided a unique assessment of MCI. This improved assessment of wrist motion disorders has highlighted sufficient differences in the dynamic CT classifications we have described and suggests that further research may result in refinement of the MCI classification system.

Investigating surface roughness of parts produced by SLS process

Selective laser sintering (SLS) has been recognized as one of the best rapid prototyping (RP) technique for producing solid models, directly from computer-aided design data by fussing together different layers with the help of laser light. Further, RP has traditionally been used for producing a solid model for visualization purpose and assessing kinematic functionality. So, the model is required to have superior mechanical integrity and surface quality for handling and model testing. This study investigates surface roughness (SR) of parts produced by SLS process. The empirical models have been purposed to predict the feasibility of different process parameters viz., laser power, scan spacing, bed temperature, hatch length, and scan count on SR. Further, these parameters have been optimized using face-centered central composite design with response surface methodology. The optimized parameters have been verified by conducting confirmation experiments.

On the kinematic functionality of a four-bar based mechanism for guiding wheels in climbing steps and obstacles

This paper describes a design of a mechanism that aims a wheel to climb obstacles, steps, or slopes with a suitable smooth path. The proposed four-bar linkage can be installed on each wheel of a vehicle, which therefore can be capable to climb stairs with suitable comfortable motion. An algorithm is formulated to design an optimum solution of the mechanism fulfilling those task requirements. A straight-line trajectory for the centre of a wheel is ensured through an easily controlled motion, and the compactness of the mechanism design makes it suitable for staircase climbing wheelchairs for aiding people with disability. Experimental tests have given satisfactory results and are shown for a practical application.

Method for the Optimization of Kinematic and Dynamic Properties of Parallel Kinematic Machines

The following paper introduces an approach, which allows the consideration of the kinematic as well as the dynamic properties of parallel kinematic machines. Based on the results of a preceding kinematic optimization, a FEM-model with arbitrary input parameters is designed. The full kinematic functionality of struts and joints used is ensured. By coupling the FEM-model to the GNU Octave numerical program system, a variety of movements including machining forces can be simulated. A Broyden-Fletcher-Goldfarb-Shanno optimization algorithm, using GNU Octave, was written and coupled to the FEM-system. Now, this algorithm is able to influence the model's arbitrary input parameters during the optimization process. Thus, the model is optimized automatically for a certain machining process and/or dynamic behavior. This procedure is demonstrated using the example of a delta robot structure originally designed by Raymond Clavel [7].

Container spaces and functional features for top-down 3D layout design

Although there have been many advances in computer-aided modelling techniques and representations of mechanical parts, there are areas where exact modelling is a handicap. One of these is 3D layout design. Here, simpler models are useful for initial design sketches to verify kinematic behaviour and organise product structure before the detailed component design phase begins. A commitment to exact, or close approximational geometry too early can imply a commitment to form before functionality has been finalised. This paper describes a system for top-down 3D layout design based on simple conceptual elements which can be used as a basis for visualisation, discussion, definition of product structure and kinematic functionality in the conceptual design phase before the embodiment or detailing begins. This tool forms a bridge between the abstract nature of the conceptual design phase and the geometric nature of the embodiment phase. The 3D layout module uses design spaces with simple geometry and kinematic connections to represent a product. The design spaces act as containers or envelopes within which the final component design is to be realised. The kinematic connections allow the behaviour of the product to be simulated to gain more information (such as overall component dimensions and areas of potential collisions) for the detailed design phase. In addition the paper describes the design process based on the proposed 3D layout design system and contrasts this with the traditional design process. An industrial case study is presented to illustrate the following advantages of the proposed approach: (i) the design process proceeds faster because unnecessary layout parameter and constraint modifications are avoided since kinematic functionality verification precedes the detail design, (ii) the design process can produce better designs since alternative solution principles can be explored early in the design process. Theoretical issues are discussed concerning kinematic constraint inheritance during design space decomposition and concerning computer support for non-rigid design spaces.