Development of Arduino based Omni Wheel Plotter

This project demonstrates and tests the feasibility of an omni wheel plotter, where plotters are used to obtain the vector and line drawings of engineering models. The plotters developed before were having rigid frame, bulky and. many of the plotters developed for academic purpose are for research purpose having less flexibility or constrained to a large extent. In this project, a plotter is developed which does not contain any rigid frame. Instead it uses a movable frame with omni wheels attached to it for mobility. The use of omni wheels makes the design of chassis or frame easy. To further simplify the design, a pivot joint suspension is built into it. The electronics part of the plotter consists of an Arduino Uno microcontroller board, ULN2003 stepper motor driver and a PCB to provide the power for running the motor drivers. The ‘G’ and ‘M’ codes are used to plot the required figure by the plotter. All connections were first designed and tested on a software called Fritzing. For programming the ‘Uno’ microcontroller, software provided by Arduino is used. The codes are communicated to the plotter with the help of HC-05 Bluetooth module. For sending these commands, a software called Coolterm is used. All software’s used for design, fabrication and coding of the electronics is based on open source license, while the chassis has been designed using SolidWorks software. These plotters can be used for plotting 2D figures and PCB circuits, they can also be used for cutting 2D shapes and removal of excess material by replacing the pen with suitable cutting tool or laser cutters

METHODS DEVELOPMENT OF STRENGTH AND RELIABILITY ANALYSIS OF ROLLING-STOCK BEARING STRUCTURE USING MATHEMATICAL MODELING METHODS

The purpose of the work is a procedure formation for the analysis of strength and reliability of rolling-stock bearing structure using methods of mathematical modeling. Its appraisal is shown by the example of improvements in a universal gondola car bearing structure. The procedure offered is formed by a mathematical modeling of bearing structure dynamic loading in the rolling-stock operation including shunting movement encounters. At the first stage of the procedure the dynamic computer simulations of a rail crew movement on way roughness are under development. As a result of modeling there are defined dynamic loads influencing a bearing structure in operation. The analysis of the stress-strain state of the bearing structure is carried out on the basis of detailed shell finite element models. The computation is carried out in a dynamic position through the method of the direct integration of nodal-relocation equations. The estimate of bearing structures fatigue life in a pivot area was carried out on the basis of the linear hypothesis of fatigue damages summation, the power approximation of a material fatigue curve and scheming dynamic stresses affecting the structure through the method of complete cycles. Within the limits of the procedure the history of loading was presented as a step function. On the basis of the results of a stress-strain state in the bearing structure of a gondola car body in a static and dynamic location there is carried out the analysis of fatigue life in a pivot area of the gondola car and the conclusions were drawn regarding crack-like defect occurrence in a center plate arrangement of a frame. There are offered three versions for updating the pivot joint of a gondola car with the purpose of its fatigue life increase. For each version of updating there are developed corresponding detailed finite element models of the pivot area and on their basis the analysis of strength and fatigue life is performed. On the basis of computation results and taking into account the manufacturability of center plate arrangement production an efficient version is recommended for updating a pivot joint of a gondola car. The pivot joint modernization according to the version offered allowed decreasing maximum acting stresses in the pivot joint by 27% and increasing service life of the welded joint elements up to 29 years.

Functional morphology of a highly specialised pivot joint in the cranio-cervical complex of the minute lizard Ablepharus kitaibelii in relation to feeding ecology and behaviour

The snake-eyed skink Ablepharus kitaibelii is one of the smallest European lizards, but despite its minute size it is able to feed on comparatively large prey. Here we investigate the diet of A. kitaibelii and the mechanisms that allow the skink to overpower relatively large and even noxious prey. High-speed cinematography showed that A. kitaibelii uses a series of shaking and battering movements to immobilise and kill prey prior to swallowing. During this process, the skinks rises up on the hind limbs and then whacks the prey sidewise on the substrate by twisting the trunk, neck and head laterally. Our analysis showed that the shaking kinematics is very uniform among the investigated specimens. The morphological investigation of the cranio-cervical system revealed that A. kitaibelii possesses a well-developed synovial joint between the odontoid process of the axis, the atlas, and the basioccipital. The odontoid process is cylindrical and slim and together with the atlas and the basioccipital it forms a highly specialised pivot joint for lateral head rotation. We propose that the occipito-atlanto-axial complex of A. kitaibelii represents a functional adaptation for additional stabilisation of the cranio-cervical complex during prey shaking. Digital data from morphological databases showed that specialised joints of this type are very rare, but do also occur in other squamate groups. Thus we hypothesise that specialised cranio-cervical joints have evolved parallel as functional adaptations to different feeding and locomotion patterns. Future studies that link feeding kinematics and locomotion to cranio-cervical morphology might elucidate the function of various specialised occipito-atlanto-axial systems of squamates.