基于触觉感知的家禽净膛机械手及其控制系统的设计.

Aiming at the problem of poultry entrails easy to be damaged in the poultry eviscerated processing, we designed the manipulator and its control system based on tactile perception in this paper. According to the size and depth of abdominal part of broiler with the general size, the maximum distance from the mechanical gripper when it is opened and the length range of the mechanical finger are respectively determined. Through the analysis of the poultry entrails, the bending degree of the mechanical fingers is determined, and then the envelope space when the mechanical gripper is closed is determined. The three-dimensional model of the mechanical gripper is established by SolidWorks software. The size of mechanical gripper is determined by the movement analysis and the assembly of mechanical gripper. The mechanical gripper is driven by a screw, the rotary motion of the stepper motor is converted into a linear motion of the slider by means of a screw, and then through the connecting rod the movement of mechanical fingers is achieved. STM32 single chip microcomputer is used to generate PWM (pulse width modulation) signal to control the move of mechanical arm in X, Y, Z axis direction, and at the same time to control the positive direction rotation of stepping motor of manipulator, achieving the closing of mechanical paw. The piezoresistive film sensor is used as the tactile sensing part of the mechanical gripper. When the pressure on the sensor becomes larger, the resistance value becomes smaller. On the other hand, when the pressure becomes smaller, the resistance value becomes larger. Single chip microcomputer can collect the voltage signal, but can not directly collect the resistance signal, so the resistance-voltage conversion module is used to make the changes of resistance value of the sensor that is caused by the changeable pressure on the sensor, which becomes the corresponding voltage signal. In this way, the ADC (analog-to-digital converter) module of single chip microcomputer is used to collected the pressure of piezoresistive type film sensor in real time installed in the inside of finger. We make the 4 broilers as a group and conduct the visceral pressure threshold test of broiler with a total of 3 groups of broilers and the pressure threshold of the mechanical gripper is determined. We compare the collected pressure with pressure threshold value that is 7.7 N, and control reverse rotation of stepping motor of manipulator, so as to control the force of manipulator paw to ensure that entrails would not endure too much force to be damaged, or would not fall off due to closing not enough. Qt Creator is used to draw the user graphical interface of poultry eviscerated manipulator, and the interface is mainly composed of serial port, display box, automatic mode, manual mode and operation control, and includes manual and automatic control modes. In automatic mode, you can enter the running distance of the 3 axes to determine the movement state of the manipulator, and at the same time, in manual mode, you can click the manual button to control the action of the robot. The PC (personal computer) and STM32 single chip microcomputer are connected by the serial data cable, and then the system is initialized. In this way, you can operate the control interface. In addition, when the manipulator gets trouble in the working process, you can click the stop button to make all the stepper motors disabled, to ensure the safety of equipment. The results of test showed that mechanical paw with the tactile system could significantly reduce the damage of entrails,the average score of visceral damage decreased from 4.75 to 4, and the evisceration rate was 87.4%. The manipulator has the advantages of stable performance, less damage to entrails, high degree of automation, friendly human-computer interface and easy control, and has high practical value. [ABSTRACT FROM AUTHOR]