Soil tillage is a very energy-intensive operation. A general expectation is to reduce energy consumption and reduce soil compaction with as few turns and interventions as possible. Thus, more and more attention is being paid to the use of active tillage machines. The aim of the present work is to test a new approach to optimize PTO-driven tilling machine operations regarding energy consumption. A real, active tillage machine, the MSS-140 type spading machine, was investigated in the Matlab® Simscape™ environment. The solid model of the spading machine was built using actual dimensions. The work done by a single spade is broken down into elementary processes. The acting forces on the implement, in each elementary process for different advancing speeds, were modelled and calculated. The model is suitable for illustrating the dynamics of loads and for calculating the mechanical work. The model was also tested in comparison with real fuel consumption. The consumed fuel quantity was measured and the energy requirement for the model calculated at three advancing speeds. A comparison between the measured and calculated energy consumption values was made: the calculated results are similar to the measured values; the mean difference is 9.91%, with a standard deviation 3.3%.
The paper introduces the use of a novel drive module with one translational and one rotational degree of freedom. The mechanism of the presented system has a timing belt setup, which enables a parallel drive of two DOF. Based on this mechanism the possibilities to build a low (2, 3 and 4) DOF manipulator are systematic presented, followed by the mathematical models for the geometry and kinematics. The advantages of the new mechanisms are underlined by presenting numerical results
The number of applications of parallel topology robots in industry is growing, and the interest of academics in finding new solutions and applications to implement such mechanisms is present all over the world. Industrywide, the most commonly used motion types need four- and six-degrees-of-freedom (DoF) robots. While there are commercial variants from different robot vendors, this study offers new alternatives to these. Based on Lie algebra synthesis, symmetrical parallel structures are identified, according to certain rules. Implementing 2-DoF actuation modules, the number of robot limbs is reduced compared to existing commercial robot structures. In terms of the applicability of a parallel mechanism (also concerning the control algorithm), it is important to determine singular configurations. Therefore, in addition to the kinematic schematics of the newly proposed mechanisms, their singular configurations are also discussed. Based on some dimensional simplifications (without a loss of generality), the conditions for the singular configurations are enumerated for the presented parallel topology robots with symmetrical kinematic chains. Finally, a comparison of the proposed mechanism is presented, considering its singular configurations.
The Mixed CAD Generating Method, developed by the first author and presented in previous papers, is able to generate gear teeth gaps from a special points cloud. The generation method requires only a few specific points from the cutting edges of the generating tools. These points can be obtained in a first approach through a simple drawing of the cutting edges. The drawings can use either mathematical equations, or simply the construction and design principles of the cutting tools. In the case of multi-edge cutting tools of a higher level of complexity, or in case of the absence of the edge equations, there exists a simpler approach. It consists in building a solid model, or obtaining the solid model of the tools from the tool’s designer or manufacturer. In these cases, the generating points are downloaded from the solid model. This paper presents two possibilities of obtaining these points with usual CAD methods.
1 December 2021 in Acta Universitatis Sapientiae, Electrical and Mechanical Engineering
The actual energy situation and the significant energy demand of agricultural production require the exploration and analysis of the general laws of the main processes in the field of energy, which is part of the borderline between the technical sciences and the agricultural sciences. Tillage machines change the physical properties of the soil, but at the same time the mechanical properties of the soil react to the implement. One of the basic works of seedbed preparation is harrowing. In this work we study the kinematics and dynamics of the active rotary harrow implements, taking into account the cutting resistance of the soil. The results obtained with the developed modeling methods, give reliable approximations to the experienced tilling processes.
Planetary gears consisting of simple external gear wheels and an internal ring gear are widely used in industry in various fields. This type of drive is most commonly found in robots, and it is also frequently used in the automotive industry, such as in wheel hub drives, in addition to general engineering. This study investigates the design of simple planetary gears manufactured with involute gearing. In simple internal gear planetary gears, the orbiting motion of the planetary gear is transferred to the output shaft by a radial balancing clutch and converted into rotary motion through the planetary gear’s guiding holes and the output element’s pins. The guiding holes reduce the planetary gear teeth strength, and the rim thickness “h” has a fundamental influence on the resulting tooth root stress. The main objective of this research is to design external gears with relief for simple planetary gears with a rim thickness “h” that does not decrease the load-carrying capacity. The dimensioning of involute gearing is well known, but the tooth root weakening effect of the clearance holes in such planetary gears is not known. Therefore, this paper focuses on analyzing how the size and position of the guiding holes influence tooth root stress, using finite element method (FEM) calculations performed in SolidWorks 2023. This study aimed to determine the rim thickness “h” required for the design of such a gear in order not to weaken the load-carrying capacity of the gear teeth. As a result of the research, the design of the guiding holes and the wheel relief holes can be performed with an accurate knowledge of their influence on tooth stress. The research results also make it possible to design this type of planetary gear using simple analytical calculation algorithms. Our goal was to define a simple design limit that could be used specifically in the preliminary design phase. This allows designers to determine the positions and dimensions of the guiding holes in the preliminary design phase without affecting the tooth stress.