关键词: 竹片分选, 运动特征分析, 二次回归正交旋转组合, 优化试验

Abstract:

Objective: Aiming at the problems of low efficiency of directional sorting before rough milling, poor sorting effect and high degree of manual dependence, we designed and developed a continuous directional feeding system for rough milling of bamboo slices to realize the mechanization, automation and continuity. Method: Taking the bamboo slices after breaking the bamboo and removing the bamboo joints as the research objects, the technical scheme of the continuous directional feeding system for rough milling of the bamboo slices was proposed, the inclined vibration lifting chain, step separation system, recognition and turnover system of bamboo green and yellow surface and mechanical structure such as automatic feeding system were designed. By analyzing the movement characteristics of the bamboo slices in the vibration sorting process and the throwing process, the mathematical model of the bamboo slice movement trajectory in the vibration sorting process was established, the trajectory of the bamboo slice parabolic movement was described, and the main influencing factors of the bamboo slice selection process were determined. Selecting the lift chain speed, the inclination angle and the length of the bamboo slices as the inspection factors, the optimization experiment of the three-factor five-level quadratic regression orthogonal rotation combination was designed. The equipment, using the bamboo slice sorting rate and the bamboo green and yellow surface recognition rate as the evaluation index, was tested and set up at the Jian'ou Pilot Test Base in Fujian. Result: The single factor test showed that the bamboo slice sorting rate increased first and then decreased with the increasing speed of the lifting chain. When the speed of the lifting chain increased from 1.5 m·s^-1 to 2.7 m·s^-1, the separation rate of bamboo slices showed a trend of increasing first and then decreasing. The inclination angle of the lifting chain increased from 25° to 45°, and the separation rate of bamboo slices improved significantly. As the length of bamboo slices increased, the rate of separation of bamboo slices increased first and then decreased. However, compared with the influences of the speed of the lifting chain and the inclination angle of the lifting chain on the adhesion and separation rate, the length of the bamboo slice had a smaller influence on the adhesion and separation of the bamboo slice. The recognition rate of the bamboo green and yellow surface was mainly affected by the speed of the lifting chain. When the speed of the lifting chain was slow, the recognition system could obtain a clearer image of the bamboo green and yellow surface, and the recognition rate of the bamboo green and yellow surface was higher. The quadratic regression orthogonal rotation combination test showed that the order of the three test factors on the bamboo slices sorting effect was: ascending chain inclination angle > lifting chain speed > bamboo length. The speed range of the lifting chain was 1.6-2.0 m·s^-1, the inclination angle of the lifting chain was 35°-42°, and the length of the bamboo slice was 1 750-1 850 mm, the bamboo slice separation and conveying effect was the best, and the bamboo slice separation rate reached 96.5%-96.8%. Conclusion: 1) Based on the analysis of the actual operation situation of bamboo slices sorting, a continuous directional feeding system for rough milling of bamboo slices based on vibration and step separation design was designed. 2) In the application test of the continuous directional feeding system for rough milling of bamboo slices, the rotating speed of the elevator chain was 1.6-2.0 m·s^-1, the inclination angle of the elevator chain was 35°-42°, the length of bamboo slices was 1 750-1 850 mm, the sheet separation and conveying effect was the best, and the separation rate was 96.5%~96.8%. In actual production, the rotating speed and the inclination angle of the elevator chain could be selected to be 2.0 m·s^-1 and 40°, respectively. Under the conditions with the above parameters, the separation effect of bamboo slices with a length of 1 800 mm was the best, and the separation rate reached 96.7%, the recognition rate of bamboo green and yellow surface was 97.6%. At this time, the separation of bamboo slices and the identification of green and yellow surfaces of bamboo were better, which could meet the needs of on-site applications.

Key words: separation of bamboo slices, motion characteristic analysis, quadratic regression orthogonal rotation combination, optimization test