混合驱动五杆花卉盘栽机构的优化设计与试验

Optimal design and experiment of hybrid-driven five-bar flower potted-seedling transplanting mechanism

为实现盘栽机构的轻简化和运动设计的灵活性,该文以一种混合驱动五杆机构来实现花卉穴盘苗盘栽运动。根据工作要求拟定机构轨迹,以变速电机最小角速度波动为目标,基于遗传算法优化得到机构中机架位置为(0,-150)和(-267.20,61.87),五杆机构的杆长分别为152.80、324.55、336.56、100.40、302.60、341.00 mm。建立花卉盘栽机构三维模型,利用ADAMS进行了机构运动仿真,验证了机构优化设计结果的正确性。对混合驱动五杆花卉盘栽机构控制系统进行了设计,试制样机并开展了花卉盘栽试验。通过进行花卉移栽试验,测试得到花卉移栽轨迹高度为265 mm,取苗倾角为140°,取苗时入钵摆角为6.92°、出钵摆角为6.27°,取苗环扣宽度小于3 mm,植苗倾角为90°,植苗时入盘摆角为13.19°、出盘摆角为4.19°,植苗段垂直轨迹大于40 mm。花卉移栽的平均成功率为87.16%,表明混合驱动五杆花卉盘栽机构可以实现花卉盘栽工作。研究拓展了混合驱动的应用领域,可为全自动花卉盘栽装备的研发提供参考。

Flower potted-seedling transplanter is usually a complex system of cylinder, hydraulic rod and electromagnetic valve, and its high price brings impediment for its promotion. Utilizing a single mechanism to achieve the kinematics requirement of seedling transplanting can be very difficult. Hybrid-driven mechanism can not only have the high transmission efficiency and carrying capacity as the single degree-of-freedom mechanism, but can also have the high flexible degree as the multi degree-of-freedom mechanism. Aiming at simplifying the potted-seedling transplanting mechanism and adding the flexibility of kinematic design, a hybrid-driven five-bar mechanism was proposed to realize the flower potted-seedling transplanting. The trajectory of the mechanism was proposed according to the work requirements and a mathematical model of hybrid-driven five-bar flower potted-seedling transplanting mechanism was built. Aiming at the minimum angular velocity fluctuation of the variable speed motor, the parameters of the mechanism were optimized through genetic algorithm toolbox of MATLAB. The rack location of mechanism was set as（0,-150） and（-267.20, 61.87） based on the optimization results of genetic algorithm. The bar lengths of five-bar mechanism were 152.80, 324.55, 336.56, 100.40, 302.60 and 341.00 mm. A three-dimensional model of flower potted-seedling transplanting mechanism was built, the kinematic simulation of mechanism was carried out by ADAMS software, and the correctness of the mechanism＇s optimization results was verified through kinematic simulation. A control system of the hybrid-driven five-bar flower potted-seedling transplanting mechanism was designed and the position mode of servo motor was adopted in order to achieve the precise position control required by the mechanism. Meanwhile, the design of the control system realized the requirements of synchronous control and real-time match control in flower potted-seedling transplanting mechanism. The structures of the five-bar mechanism and transplanting arm mechanism were designed and the parts of these mechanisms were machined, and then a prototype was assembled to carry out the experiment research of flower potted-seedling transplanting. Through the experiment, the height of flower transplanting trajectory was measured as 265 mm. When the transplanting claw was picking up the potted-seedling, the azimuth angle was 140°, the swinging angle was 6.92° in the process of claw entering the potted-seedling, the swinging angle was 6.27° in the process of claw leaving the potted-seedling, and the width of buckle was less than 3 mm. When the transplanting claw was planting the potted-seedling, the azimuth angle was 90°, the swinging angle was 13.19° in the process of claw entering the potted-seedling, the swinging angle was 4.19° in the process of claw leaving the potted-seedling, and the vertical trajectory height was longer than 40 mm. The average successful rate of 5 transplanting experiments was 87.16% which indicated that hybrid-driven five-bar flower potted-seedling transplanting mechanism can realize the flower potted-seedling transplanting work. Meanwhile, the upright degree and success rate of picking up and planting the flower potted-seedling were ensured in the process of transplanting work. The application field of hybrid drive is extended in this article and a new choice for the design of automatic flower potted-seedling transplanting equipment is provided as well.