Modeling Of Blueberry Plants Vibration In Multi Degree Of Freedom System And The Simulation Study

Blueberry has been widely respected because of its superior health and medicinal value, whose nutritional value is higher than apples, grapes, oranges and other fruits, known as ’the king of the fruits’ by Food and Agriculture Organization (FAO) of the United Nations. It is also identified as human health food in twenty-first century. Cultivated blueberries have significant economic benefits, and the expanding the planting area is an inevitable trend. However, blueberry planting scale and planting area are also limited because of several reasons:a) our country totally dependents on artificial picking, and b) picking maturity period is short, and c) high labor intensity and low efficiency, etc. The development of mechanical picking blueberries has been viewed as the urgent demand and inevitable trend of blueberry industry in china.For the development of blueberry picking machine, calculations of the exciting force of picking, and study of picking device for picking the exciting force and picking device under the action of the plant vibration law, and theoretical exploration of the blueberry picking vibration should be done from the theory and experiment. Firstly, one studied the growth, structure, regularity and pruning of blueberry plants. One established the physical model on the basis of former theory, and also established mathematical model of the blueberry plant in the absolute coordinate system and each branch coordinates.The solution of multiple degree of freedom vibration models of blueberry plants is based on the mathematical model of blueberry plants. And it adopts linear multiple degree of freedom vibration theory to establish multiple degree of freedom vibration model of blueberry plants. At the same time, it seeks suited eigenfunction to calculate the main modes of vibration models of multiple degree of freedom system for the natural frequencies. In addition, it makes use of Duhamel integral to get the corresponding regular integral modal response of blueberry plants multiple degrees of freedom model of the natural frequencies of vibration, under the functions of the point action step excitation force and point action non-periodic excitation force, by the orthogonal transformation and canonical transformationIt lays the foundation for solving the blueberry fruit picking vibration,which includes speciation analysis of blueberry plant vibration effect of different types of excitation, the vibration shape classification and constructed response vibration equation, integral solving vibration equation using the blueberry plant vibration normal modes, and getting the blueberry plant branches at all levels vibration output response.According to point role transient excitation force and point role transient excitation force acting on vibration modes of blueberry fruits when planting blueberries, making use of each branch of the coordinate transformation matrix and blueberry plants branching vibration response at all levels is to find the result of vibration output response relative to the ground in the end of long sticks with blueberry fruits. Making use of Lagrange equation to establish blueberry fruits vibration equation is for the purpose of getting the solution of the end of branches vibration output response of blueberry fruits, and then to get the the vibration output response of blueberry fruits with respect to the ground. By the stress analysis of the blueberry fruits, point role of transient excitation force and periodic excitation force acting on the picking vibration force of blueberry plants can be solved.Analyzing picking device working principle, making use of "given travel velocity ratio method" and "graph method" to optimizing the design of picking device transmission mechanism, and the kinematic analysis of transmission mechanism should be done. In addition, we analyze the actuators at the end of picking device by dynamics, optimize the design and select picking device driving elements, and calculate picking centrifugal force size of picking device output when picking machine works. By analyzing picking device and the blueberry plant interactions and picking device and the blueberry plant coordinate transform matrix, obtained the picking excited force from each brand point of blueberry plants when they interact each other, according to the blueberry fruits’ picking vibration force when the picking device acts on blueberry plants through picking excited force.By using orthogonal test method, one designs the parameter combination of picking device, and does the orthogonal test of picking machine working parameters, and analyses the effect of picking machine working parameters on the quality and efficiency of picking blueberry fruit in order to heighten the picking quality and picking efficiency of blueberry fruit. Best work parameters of the blueberry picking test has been established to support the experiment of blueberry picking, and to give the statistical analysis of picking quality and efficiency of blueberry fruit, and to evaluate the picking quality of the best device parameters.