Study On The Reciprocating Mechanism With Approximate Pause And Its Application In The Seedling Transplanting Machine

In industrial production and daily life, many parts of machine require a pause(approximate pause) in specific position during the process of reciprocating motion. For example,in the textile and light industry machinery, air jet loom requires the sley bar of playing weft insertion mechanism to have a pause in the right position of the spindle rotation angle of 80 degrees, so that we can improve technological properties of the loom. In agricultural machinery, two long approximate pauses in a reciprocating motion cycle is often necessary. For example, Ferrari FPC Transplanter requires the seedling parts of the seedling mechanism to have a similar pause in the two limit positions and the success rate of the seedling will be greatly improved. In packaging machinery, several approximate pauses in a reciprocating motion cycle is necessary to meet the processing technology.Based on the above requirements and many kinds of reciprocating motion mechanism with pause time at home and abroad, approximate a pause time relative longer reciprocating motion mechanism which is made conveniently and pause time can be parameterized. Through parameter optimization, a special case of the mechanism which has two long pauses in reciprocating motion cycle is applied to the test-bed of seedling transplanting mechanism. The experimental results showed that the improved mechanism has longer pause time in two limit positions and the success rate of seedling is significantly higher. The main contents of this paper are as follows:1) The development status of the existing reciprocating motion mechanism with pause time and seedling transportation mechanism are analyzed, and a new type of reciprocating motion mechanism—Reciprocating Motion Mechanism with Pause Time base on Planetary Gear Train is proposed.2) The working principle and structure characteristics of the mechanism are described, and the kinematic model of the mechanism is established. The computer aided analysis and optimization software is developed based on MATLAB, the influence of the parameters on the motion of the mechanism is analyzed.3) According to the short-time pause problem that seedling feeder of Ferrari FPC transplanter has in two limiting positions, parameters of reciprocating motion mechanism with pause time base on planetary gear train are optimized and the optimal parameters of the mechanism meet the requirements.4) According to the optimal structure parameters, the design of the improved mechanism is carried out. The 3D model of the improved mechanism is built and it is introduced to the ADAMS virtual simulation, the simulation results are in agreement with the theoretical results, which verifies the correctness of the theoretical model and the simulation model.5) According to the design of the improved mechanism, the test-bed of feeding seedling mechanism with pause time is designed and made Then it is tested and the experimental results are basically consistent with the theoretical analysis. The results show that the pausing time of seeding receiver in two limiting positions is about 2.65 times longer in the same sending seedling period. Therefore, the realization of the application of the mechanism is verified.