Design And Implementation Of A Desktop Robotic Arm With Four Degrees Of Freedom Based On Arduino

Robotic is a programmable actuator with a certain degree of autonomy,which can move in its environment to perform the expected tasks.The robotic arm is the action execution device of a robotic to grasp and move objects.With the further development of all walks of life in our country,the demand for robotic arm is becoming more and more strong.Small enterprises and small factories also have the demand for deploying robotic arms to reduce human labor.There is a real demand for a kind of small and lightweight robotic arms in the market.This requires a small,low-cost,rapidly deployable desktop robotic arm on the market to solve the cost and complex process sensitive problems of small enterprises.In this paper,the D-H parameter method is used to analyze the forward kinematics of the robotic arm with four degrees of freedom(DOF),and the forward kinematics equation is obtained.The geometric method is used to analyze the inverse kinematics of the robotic arm with 4-DOF,and the solution of each joint angle of the inverse kinematics is obtained.After that,based on the selection of the driving motor,the mechanical structure and the functional requirements of the robotic arm,the hardware circuit design of the main control board of the robotic arm is analyzed and determined.The hardware circuit of the main control board includes power module,main control module,USB module and stepper motor drive module.The main control board uses 12V-DC input,12 V is the power supply to the stepper motor drive module,and 12 V is transferred into 5V to supply power to the chips.The AVR MCU ATmega2560-16 AU is choosed as the main control MCU,and the AVR MCU ATmega16U2-MU is choosed as the USB control chip.In order to make full use of the space,the expansion port board is designed.The external expansion port and the driving circuit of air valve and pump are concentrated on the expansion port board.In addition,the fourth joint with suction head(end effector)is designed to complete the action of sucking and releasing objects.Use PADS 9.5 development tool to draw schematic and PCB layout,and fully consider the problems may accur in the actual assembly process.Secondly,the Arduino integrated development environment which matches the hardware of AVR MCU is selected for the software part.In the part of software programming,the communication module,encoder module and inverse kinematics module are designed.And the open source embedded G code compiler and motion controller Grbl is transplanted.The upper computer sends Gcode through the serial port assistant to control the robotic arm to execute the corresponding action.Finally,by downloading the bootloader in advance,the fast-firmware-download function of the main control board is improved.And a special fast download fixture is designed and manufactured,which can quickly download firmware with a single USB cable.The basic function of the 4-DOF desktop robotic arm is tested.The power supply of the main control board is normal and it can communicate with the upper computer.Repeat positioning accuracy meets the usage requirements.The fourth joint can suck and release light objects.