The active fault-tolerant control approach relies heavily on the occurred faults. Higher performances and more rigorous security requirements have invoked an ever increasing demand to develop real time fault detection and isolation system. The problem of fault diagnosis using analytical redundancy (model-based) methods has received increasing attention during recent years due to the rapid growth in available computer power. The main objective is to design and maintenance a fault-tolerant control system which guarantees a high overall system reliability and dependability both in nominal operation and in the presence of faults. Such an objective is achieved by a control performance index, which is proposed based on system reliability analysis. The methods involve generation and evaluation of signals that are accentuated by faults that have actually occurred. The procedures for generating such signals, called residuals, are based on two main distinct approaches. Direct approach consists in the elimination of all the unknown variable , keeping input-output relations involving only observable variables. Indirect approach estimates states, outputs or parameters in order to generate discrepancy signals obtained by the difference between the actual variables and their estimates.
Mechanization in Agriculture
Vol. 61 (2015), Issue 7
Table of Contents
The survey forms that were prepared have been filled by 122 farmers who were tractor owners and have been analyzed. The farms were evaluated in two groups; the means are determined for Group I farms (1-259da), Group II farms (260da&greater). The most preferred usage model of multi-farm use of machinery was collectivization with neighbors. The busiest months for tractor using were April, October and September. According to different modellings, it was found that 1 tractor could be used in common by 4 farms in April in which the tractors was being used more intensely in Group I farms. It was determined that, according to the general opinions of the local farmers, “Machine Rings” was appropriate for the circumstances of Eskisehir. As it was determined that 1 tractor could not be used in common by even 2 farms in April, it was considered that it might be suitable to have tractors belong themselves when the land size was taken into account in Group II farms. When compared ownership with rental in terms of costs, having a tractor generally seems advantageous.
Harvesting rain-fed chickpeas (Cicer arietinum L.) from fallow fields in developing countries is currently a manual process performed by laborers in a tedious manner at a low level of efficiency. A tractor-pulled harvester was built in which a chain conveyor transfer harvested material. A tractor-mounted harvester was then redesigned, which incorporated a modified stripper header to detach pods from the anchored plants together with a pneumatic conveyor mechanism. The resulting machine benefitted from being light-weight and having good maneuverability. Reduction of total losses from over 50% to close to 25% over a seven-year period confirms the potential of the prototype for commercialization.
This work is dedicated to the problem of ecological agriculture. The analysis of existent technologies of minimum till of soil is conducted. The more similar examples to ecological agriculture are separated on the example of such system implanted in PE "Agroecology". We offer a system of concepts of till of soil for maintaining its fertility and growing ecologically clean products of crop production. We light up the problem of insufficient maintenance of moisture and ways of destruction of non-arable sole by mechanical and biological character. We offer an example of technological operations of till of soil that is implanted for ecological and biologically restorative agriculture.
PLANTERS FOR RESOURCE-SAVING GRAIN CROPS CULTIVATION TECHNOLOGIES IN THE CONDITIONS OF NORTHERN KAZAKHSTANpg(s) 17-18
The paper presents the development of pneumatic grain drills adapted to the local conditions of Northern Kazakhstan. They have simple structure, low cost and high flexibility, high productivity, low power consumption and can be aggregated to a wide class of tractors from 1.4 ton to 8.0 tons.
ENHANCING COMPETITIVENESS AND SUSTAINABILITY OF AGRI-FOOD SECTOR THROUGH MARKET-ORIENTED TECHNOLOGY DEVELOPMENT IN AGRICULTURAL KNOWLEDGE AND INNOVATION SYSTEM IN BULGARIApg(s) 19-22
The paper considers priority goals of future sustainable development and assurance of food quality and safety in agricultural and food sector and underlines the necessity of establishment of Agricultural Knowledge and Innovation System (AKIS) in Bulgaria based on a production model with market-focused technology development system. Knowledge-based economy, and particularly the searched increase in competitiveness in agriculture and food industry, could be reached by creation and distribution of knowledge and innovations among stakeholders and networking. The establishment of such a technology development system would incorporate three main elements: measurement of inputs, market-focused technology development and information systems. It would foster rural development through knowledge exchange between stakeholders in support of production, marketing and processing of agricultural and food products, as well as natural resources management. AKIS is a framework embracing all the actors and their interactions in creation and transfer of knowledge in new and effective ways.
One of the most important characteristics of the high performance operation of a state-of-the-art sugar beet harvester is the provision of the conditions that make impossible the damaging of sugar beet roots immediately during their digging out of the ground as well as their loss in the form of broken off tails, which either remain in the ground or get left on the field surface. It is quite obvious that the highest probability of damaging sugar beet roots exists at the instant of their impact interaction with the digging tools, because then the bodies of the roots are tight in the ground. This is to the greatest extent applicable to vibrating digging tools, which can be found on the majority of up-to-date sugar beet harvesters manufactured worldwide, when they operate under the conditions of dryer and harder soil.
Therefore, we have carried out theoretical research into the process of impact interaction between the body of a sugar beet root fixed tight in the ground and the vibrating digging tool, the results of which provide sufficient grounds for determining the optimal kinematic and design parameters of the vibrating digging tool stipulated by the requirement to eliminate the damage of roots during their digging out of the ground. At first, we developed an equivalent schematic model of the force interaction between a sugar beet root fixed tight in the ground, which was approximated by a regular cone, and two shares of the vibrating digging tool simultaneously oscillating in the vertical longitudinal plane at the preset amplitude and frequency and moving onward. Under these conditions, the body of the sugar beet root made contact at one point with only one share of the digging tool, i.e. they came in asymmetric contact and their impact interaction took place. We introduced the axes of a three-dimensional Cartesian coordinate system and found the analytical expressions for all forces applied to the sugar beet root at the specified point and also for the force of its bond with the soil. Also, we took into account that an impact momentum was applied at the point of contact at the moment of impact, its value was found analytically, and further we found its projections on the coordinate axes. Then we applied the theorem of variation of the momentum during impact and, following the substitution into it of all found values and transformations, we obtained a new system of equations that characterised the impact interaction process under consideration.
The obtained system of equations was solved using Cramer’s rule on a PC with the software programme developed for this purpose. As a result, we found the digging share vibration frequency and soil running depth ranges, within which the requirement to eliminate the damage of tail parts of root bodies fixed rather tight in the ground was met. Applying the devised theory it becomes possible to determine the kinematic and design parameters of the vibrating digging tool that ensure observance of the requirement to eliminate the breakage of root bodies during their lifting from the ground, within a wide range of the soil’s mechanical and physical characteristics.