Design and parameter optimization of removing coconut fiber device by bionic steel wire roller brush based on characteristics of claw-toe

In order to solve the problems such as low processing efficiency and vulnerable to injury in the manual peeling of coconut fiber, a device for removing coconut by bionic steel wire roller brush based on the characteristics of claw-toe was designed. Bionics studies show that many animals in nature have very perfect soil excavation and nut peeling organs after a long period of evolution, and gradually form an optimized geometric structure and excellent mechanical properties, so that they can obtain large cutting force during the digging and feeding process without damaging themselves. For example, the claw-toe can plane the soil surface easily, and the outer edge of claw-toe is curved blade structure and has certain elastic toughness. Because of the similarity between the removal process of coconut fiber and the action of digging soil and gnawing nuts, a mechanical method of removing coconut fiber by using steel wire roller brush was designed with claw-toe as the bionic prototype in this study. On the one hand, the working performance of coconut fiber removal mechanism is affected by the mechanical structure parameters, on the other hand, it is influenced by the irregular shape of coconut. The study was based on the technological requirements of coconut fiber removal and the natural characteristics of coconut. In this paper, a scheme of removing coconut fiber by bionic steel wire roller brush was put forward, and a device for removing coconut fiber was developed. The device was mainly composed of a steel wire roller brush, a coconut clamping mechanism and a feeding mechanism, which can realize the removal, clamping, fixing and feeding of the coconut. In the work, it relied on the cutting edge of steel wire section to brush the coconut fiber, and combined the elastic toughness of the steel wire to achieve no damage to the coconut shell after removing the coconut fiber. According to the preliminary test and analysis of mechanical data in the process of coconut fiber removal in the reference project, there were many factors affecting the performance of coconut fiber removal, such as moisture content of coconut, material of the executive end of coconut fiber removal and outer diameter size, etc. In this study, clothes removal was carried out for coconut of the same quality within a certain range of moisture content, and the influence law of coconut fiber removal device on removal performance was emphatically analyzed. Three factors including the rotational speed of the roller brush, the diameter of the bristles and the spacing of the bristles were taken as the objects for experimental analysis and research. The synchronous coconut was selected as the experimental raw material, and the equatorial outer diameter range was controlled at 175 to 185 mm, and it was a matured coconut of non-coconut green. The parameter optimization experiment was carried out by using the bionic steel wire roller brush device to remove the coconut fiber, and the Design Expert software was used to carry out the test plan design and the result data analysis. The test results showed that the rotational speed of the roller brush had the greatest influence on the thickness of the coconut fiber, the influence of the spacing of the bristles was second, and the influence of the diameter of the bristles was the smallest. When the rotational speed of the roller brush was constant, the thickness of the coconut fiber increases first and then decreases with the increase of the spacing of the bristles. However, when the rotational speed of the roller brush increased, the variation of the thickness of the coconut fiber was not obvious. When the spacing of the bristles was fixed, the thickness of the coconut fiber removal would gradually increase with the increase of the rotational speed of the roller brush. The influence of the diameter of the bristles on the thickness of the coconut fiber is significant; when the diameter of the bristles was constant, the bristles were planted. The spacing had little effect on the thickness of the coconut fiber. The regression analysis results of the test data showed that the optimal combination parameters of the device were as follows: the rotational speed of the roller brush was 970 rad/min, the bristles diameter was 6 mm, the bristles planting distance was 10 mm, and the optimal combination parameters were predicted to be 31.24 mm. Repeated tests proved that the optimal combination parameters can reach the specified thickness of the undressing, and did not damage the inner coconut shell, which met the needs of deep processing of coconut.