| China’s modern poultry industry is developing towards digital and intelligent direction,automation equipment has been widely used in large-scale farms to replace human labor,but there is a lack of corresponding automation equipment in the identification and treatment of dead chickens.Dead chicken collecting robot is a best way to solve the above problem,it is not affected by complex henhouse environment,can automatically detect and collect dead chickens,to avoid the direct contact with dead chickens workers,reduce the disease spread through the flock and the risk of human infection,also can reduce labor costs on chicken farms,improve the economic benefit.This paper focuses on the picking up function of the dead chicken picking up robot and takes the end-effector as the research object,the aim is to solve the problem that the caged broiler aged 3-7 weeks is difficult to grasp due to the large size change and the complex environment,based on the underactuated theory,the design and simulation of the end-effector of the dead chicken pickup robot with underactuated link were studied.The main research work of this paper is as follows:1)Based on the underactuation theory,the overall scheme design of the end-actuator is carried out,and the software and hardware design of the manipulator control system based on STM32 processor,stepping motor and various sensors is completed.The functions of clamping force detection and control of the manipulator,body surface temperature detection of chicken to prevent the live chicken from mistakenly grasping are realized.2)The basic data and mechanical and physical properties of broiler chickens were collected.The body size,body weight and normal temperature range of broiler chickens aged 3-7 weeks were collected and analyzed.Through the compression test,the stress threshold of each week age broiler was obtained,and the upper limit of the manipulator’s holding force was determined to be 80N.Through the body surface friction coefficient measurement test,the friction coefficient between each week age broiler and rubber material was obtained,and combined with the standard weight of each week age broiler,the lower limit of manipulator’s holding force was calculated as 70N.3)The statics analysis of mechanical finger mechanism and the design of mechanical finger structure are carried out.In order to obtain the basic conditions of stable grasping,the influence of four grasping configurations on the grasping stability was analyzed,and the parametric model of mechanical finger was established by using ADAMS software.After the objective function,design variable and constraint conditions of mechanical finger optimization were clarified,the optimal design of mechanical finger was carried out,and the optimization results showed that the objective function increased by 28.6%.According to ADMAS optimization results,finger mechanism,transmission mechanism and frame of manipulator are designed in UG software,and Y type connecting rod and triangle connecting block are analyzed by finite element method.The results show that the maximum stress of y-shaped connecting rod is 37.89mpa,which is far less than the yield strength of no.45 steel,which is 836Mpa.The maximum stress of triangular connecting block is 7.62mpa,far less than the yield strength of 6061 aluminum alloy,which is 110Mpa.The structural design of key connecting parts is reasonable.4)The motion simulation analysis and actual grasping test of manipulator are carried out.The assembly and model inspection of the manipulator were carried out.The UG test report showed that the manipulator model passed the test without interference or damage;Taking the breast width of broilers as the diameter,the geometric model of the dry part of broilers of each week age was established and the grasping range was simulated.The results show that the mechanical finger has a large grasping range and has a good grasping effect on each week age broiler model;The motion simulation analysis of the manipulator was carried out under the conditions of empty grasping,grasping 3-week old broilers and 7-week old broilers,and the results showed that the manipulator’s transmission was stable,the motion of each knuckle and the contact force of each knuckle met the design expectation;The grasping experiment of broiler chickens aged 3 weeks and 5 weeks was carried out with manipulator prototype,and the results showed that the average success rate of robots grabbing 5-week-old broilers was 88.3%,and the average success rate of 3-week-old broilers was 76%,with high efficiency,and the design goal was achieved. |
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