Aiming at the problem of singular area in the working space when designing the parallel casting mechanism of the pouring robot, and the sensitivity of the pouring liquid to acceleration of the ladle, we propose a gene...
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Aiming at the problem of singular area in the working space when designing the parallel casting mechanism of the pouring robot, and the sensitivity of the pouring liquid to acceleration of the ladle, we propose a genetic fusion algorithm of particle swarm optimization with angle and distance observers to find the optimal control point. Numerical analysis shows that it is feasible to change the tilting angle of the ladle to make it traverse the singular regions safely. According to the simplified method of single pendulum, the sloshing model of pouring liquid is established, and the segmented acceleration planning method considering the sloshing of pouring liquid is proposed in combination with the characteristics of high-speed cam motion. Numerical and experimental studies show that the segmented acceleration planning method can make the parallel pouring mechanism reach the set position in the shortest time while moving along the planned trajectory, and ensure that the sloshing of pouring liquid is within the safe range.
Currently, workers in sand casting face harsh environments and the operation safety is poor. Existing pouring robots have insufficient stability and load-bearing capacity and cannot perform intelligent pouring accordi...
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Currently, workers in sand casting face harsh environments and the operation safety is poor. Existing pouring robots have insufficient stability and load-bearing capacity and cannot perform intelligent pouring according to the demand of pouring process. In this paper, a hybrid pouring robot is proposed to solve these limitations, and a vision-based hardware-in-the-loop (HIL) control technology is designed to achieve the real-time control problems of simulated pouring and pouring process. Firstly, based on the pouring mechanism and the motion demand of ladle, a hybrid pouring robot with a 2UPR-2RPU parallel mechanism as the main body is designed. And the equivalent hybrid kinematic model was established by using Eulerian method and differential motion. Subsequently, a motion control strategy based on HIL simulation technique was designed and presented. The working space of the robot was obtained through simulation experiments to meet the usage requirements. And the stability of the robot was tested through the key motion parameters of the robot joints. Based on the analysis of pouring quality and trajectory, optimal dynamic parameters for the experimental prototype are obtained through water simulation experiments, the pouring liquid height area is 35-40 cm, the average flow rate of pouring liquid is 112 cm3/s, and the ladle tilting speed is 0.0182 rad/s. Experimental results validate the reasonableness of the designed pouring robot structure. Its control system realizes the coordinated movement of each branch chain to complete the pouring tasks with different variable parameters. Consequently, the designed pouring robot will significantly enhance the automation level of the casting industry.
This paper describes the advanced control technology for the tilting-ladle-type pouring robots in the casting industry. In the pouring process in which the molten metal is poured into the pouring basin of the mold by ...
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ISBN:
(纸本)9789897583803
This paper describes the advanced control technology for the tilting-ladle-type pouring robots in the casting industry. In the pouring process in which the molten metal is poured into the pouring basin of the mold by tilting the ladle, it is difficult to pour the molten metal as desired pouring flow rate by the operator. Because the pouring flow rate is manipulated indirectly by manipulating the ladle's angle. In order to solve this problem, in previous studies, we developed the direct manipulation system of the pouring flow rate in the pouring robots. However, the error between the desired and the actual pouring flow rate can be caused by the disturbances in the pouring condition. Therefore, in this study, we develop the pouring flow rate feedback control for improving the tracking performance. In this approach, the pouring flow rate can be estimated by using the extended Kalman filter, and the feedback controller can be constructed by the gain-scheduled PID control based on the estimated flow rate. The developed system is applied to the laboratory-type pouring robot. According to the experiments, the operator can manipulate the pouring flow rate as desired, even in the pouring condition with the disturbance.
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