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Aiming at the installation of prefabricated wall panels in today's assembly building, a new type of wall panel vertical machine is designed, which realizes the adjustment of the pitch position and position of the end grabbing device through the arm turnover mechanism, thus realizing the positioning and installation of prefabricated wall panels. The boom turnover mechanism belongs to the hydraulic linkage mechanism. Through the mechanical simulation analysis, it is found that the boom landing mechanism belongs to the main bearing mechanism and the driving cylinder has the largest load. Therefore, a scale optimization model is established for the boom landing mechanism to minimize the maximum load of the driving cylinder as the objective function. Based on the complex method, the optimal scale parameters of the boom turnover mechanism are obtained, and the maximum load of the driving cylinder before and after optimization is reduced by about 36%. Drive cylinder performance is significantly improved. The virtual prototype is built by Creo software and the rigid body dynamics simulation analysis is carried out. The mechanism scale optimization model is validated. Finally, the prototype development and the construction test are carried out, and the working performance of the boom turnover mechanism meets the design requirements.

Black soil region can serve as the main production area of commodity grain in Northeast China. There is the soil quality decline of cultivated land in recent years, such as the thinner and harder land. Among them, the efficient return of agricultural waste as a carbon source can be an important way to improve soil quality. However, it is still lacking in the regional, agricultural production system model using the regulation of the carbon cycle between plant and animal, in order to promote the return of carbon to the field for the recovery of black land fertility. This study aims to improve the soil organic matter content of black land for recovery. The research object was selected as Qiqihar City located in the hinterland of Songnen Plain in Heilongjiang Province of China. The soil carbon budget of each county was calculated to compare the difference between the soil carbon input and output of different crops. The agricultural carbon balance model was established for plant and animal husbandry using multi-objective linear programming. The least carbon emission and the highest economic benefit were taken as the main targets, while the efficient use of agricultural and waste resources was the secondary target. As such, the balance between soil carbon emission and carbon input was determined, according to the situation of each county. The results showed that the adjustment plan in each county was optimized to reduce the rice planting area, while increasing the cow farming scale and maize planting area with high biomass. There was no decrease in the soil carbon pool of farmland after the full utilization of the waste of cultivation and breeding industry. However, the scale of plant and animal husbandry at the county level should be adjusted, according to the local conditions. Taking Nehe City with a large soil carbon deficit as an example, the maize planting area increased by 46%, while the scale of beef breeding should be reduced by 63%, and the scale of cows, pigs, sheep and poultry breeding increased by 85%, 54%, 76%, and 71%, respectively, in order to balance the carbon input and agricultural economic benefits. Take Longjiang County with a small soil carbon deficit as an example, the rice planting area, and the beef and pigs breeding industry should be reduced, while the corn and soybean planting area increased, and the scale of cows, pigs, and poultry also increased. The organic materials returned to the field were replaced by 33%-49% of the fertilizer nitrogen input after the planting and breeding scale, particularly for the higher soil quality and the soil nitrogen carrying capacity. Moreover, the soil nitrogen-carrying capacity of the three main crops showed an increasing trend, except for the maize planting in Kedong and Keshan County. The agricultural “carbon balance” development model can be expected to serve as the scientific basis for the efficient utilization of agricultural waste resources. The finding can also provide a strong reference to realize the “double carbon” strategy in the black soil area. [ABSTRACT FROM AUTHOR]

Aiming at the problems that the coupling effect of multi-joint series mechanisms on the kinematic performance of the end-effector, the kinematic characteristics of series-parallel hybrid mechanisms were analyzed, and a multi-parameter plane model was proposed to realize visualized design. Based on screw theory, the kinematics transfer matrices of serial and parallel joints were established respectively, and the corresponding performance indexes were set up. According to the multiparameter plane model, the coupling relationship among parameter scale, orientation workspace, and performance indexes were further revealed through a three-dimensional visualization graphics. Finally, the values of parameters, the range of high-quality orientation workspace, and the distribution of indexes were confirmed. The results show that the global performance indexes of the shoulder and wrist joints are as 0.78 and 0.67, respectively, and the global condition number of the elbow joint is as 2.38. The hybrid configuration has functions similar to that of the human arm joints, and gives full play to the comprehensive advantages of series and parallel mechanisms. [ABSTRACT FROM AUTHOR]

A fully symmetric 4-URU parallel mechanism with 3T1R motion is studied. Based on the screw theory, the degree of freedom of the mechanism is verified, the mathematical model of the positive and negative solution of the mechanism position is established, and the singular configuration of the mechanism is obtained. The workspace of the mechanism is solved by the numerical search method. The key scale parameters of the mechanism are optimized by examining the influence of various scale parameters on the workspace. The results of numerical calculation and motion simulation show that the kinematics model and performance analysis are correct and reasonable, and the results can provide references for mechanism mechanics analysis, structure design.

By analyzing the physiological structure and motion characteristics of human ankle joint, a four degree of freedom generalized spherical parallel mechanism is proposed to meet the needs of ankle rehabilitation. Using the spiral theory to analyze the motion characteristics of the mechanism and based on the method of describing the position with spherical coordinates and the posture with Euler Angle, the inverse solution of the closed vector equation of mechanism position is established. The workspace of mechanism is analyzed according to the constraint conditions of inverse solution. The workspace of the moving spherical center of the mechanism is used to match the movement space of the tibiotalar joint, and the workspace of the dynamic platform is used to match the movement space of subtalar joint. Genetic algorithm is used to optimize the key scale parameters of the mechanism. The results show that the workspace of the generalized spherical parallel mechanism can satisfy the actual movement space of human ankle joint rehabilitation. The results of this paper can provide theoretical basis and experimental reference for the design of ankle joint rehabilitation robot with high matching degree.