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<\/a>Figure 1.<\/strong> The various components of the pick-and-place robot.<\/p><\/div>\n As shown in Figure 1<\/strong>, the robot consists of two sections:<\/p>\n The omnidirectional platform The wooden plate is 8-mm thick and 500 mm in diameter. The three dc gear motors are of 12V and 300 rpm. They’re fixed at the bottom side of wooden plate using clamps at a specific angle as shown. All three motors are fixed at an angle of 120o<\/sup> from one another.<\/p>\n The omnidirectional wheels are attached to the dc motor shaft directly, using the given screw in the motor shaft.<\/p>\n The robotic arm<\/strong><\/p>\n Block diagram 1. Remote control section:<\/strong> used to remotely control all of the robot’s movements<\/p>\n 2. Robot control section:<\/strong> used to actuate the three dc motors and six servo motors. It also controls the robot’s motion basd on the commands from the remote control.<\/p>\n The remote control section<\/strong><\/p>\n Figure 2.<\/strong> The block diagram of the omnidirectional PnP robot, using Arduino NANO and the HC12 module.<\/p><\/div>\n The primary building blocks of the remote control include Arduino NANO board, the joystick, pushbuttons, the HC12 RF trans-receiver module, and an LED.<\/span><\/p>\n Arduino NANO:<\/span><\/strong>\u00a0The remote control\u2019s MCU responsible for the complete operation of this section.\u00a0<\/span><\/p>\n Joystick:<\/span><\/strong>\u00a0The two-axis joystick has two potentiometers internally and is moved in either direction (up-down and left-right).\u00a0<\/span><\/p>\n Note: the resistance value varies. This will generate variable analog output voltages, Vx and Vy. These two voltages are given as input to Arduino NANO\u2019s internal ADC. The joystick controls the motion of the omnidirectional base (platform), which moves in all directions as per the joystick.\u00a0<\/span><\/p>\n Pushbuttons:<\/span><\/strong>\u00a0These give digital input (logic 0) to Arduino, control the robotic arm\u2019s movement, and control the six servo motors. Two buttons are required for each servo motor, for a total of 12 buttons.\u00a0<\/span><\/p>\n HC12 module:<\/span><\/strong>\u00a0This is an RF trans-receiver module that works on the 434 MHz frequency. It receives code (data) serially from Arduino and transmits it.<\/span><\/p>\n LED:<\/span><\/strong>\u00a0This light blinks every time that code is transmitted.<\/span><\/p>\n The robot control section<\/strong><\/p>\n Figure 3.<\/strong> This bock diagram shows the main parts of the robot’s control section.<\/p><\/div>\n \u00a0<\/span>The main building blocks of the robot\u2019s control section include Arduino, Bluetooth, the HC12 module, the motor driver, and the dc and servo motors.<\/span><\/p>\n Arduino NANO:<\/strong>\u00a0Similar to the remote-control section, Arduino is also used as an MCU in this control section and is responsible for its full operation.\u00a0<\/span><\/p>\n Bluetooth module:<\/strong>\u00a0It receives transmitted code from a smartphone\u2019s Bluetooth and sends it to Arduino for further action.<\/p>\n HC12 module:<\/strong>\u00a0It receives transmitted code from the remote control\u2019s HC12 module and sends it to Arduino.<\/p>\n Motor driver module:<\/strong>\u00a0It provides the dc motors with the required voltage and current. The motor drive receives input from Arduino and drives the three dc motors based on the robot\u2019s desired movements.<\/p>\n Dc motors:<\/strong>\u00a0The three dc motors provide omnidirectional movement to the robot (via the wheels).<\/p>\n Servo motors:<\/strong>\u00a0The six dc servo motors provide the robotic arm with six different movement options (6 DoF), allowing it to \u201cpick-and-place\u201d objects.<\/p>\n Circuit diagram for the remote control Figure 4. The remote control’s circuit diagram for the omnidirectional pick-and-place robot.<\/p><\/div>\n There are 12 pushbuttons connected to Arduino’s digital pins D0 \u2013 D11. Each button’s other terminal is connected to the ground.<\/span><\/p>\n The robot’s control circuit:<\/strong><\/p>\n Figure 5.<\/strong> The control circuit diagram for the omnidirectional pick-and-place robot.<\/p><\/div>\n <\/p>\n The remote control’s circuit operation Next, Arduino sends this code serially to the HC12 module, which transmits it using the 434 MHz carrier frequency.<\/span><\/p>\n When the joystick moves from left to right, its one-pot resistance value varies. The change in resistance varies the Vx voltage of the joystick from 0 to 5 V. Arduino reads this analog voltage on pin A0 and converts it into a digital value between 0 to 1023. When this value is above 700 or below 300, it will transmit the code.<\/span><\/p>\n Similarly, when the joystick is moved up and down, its pot resistance value varies, which varies the joystick’s Vy voltage from 0 to 5 V. Arduino reads this analog voltage on pin A1 and converts it into a digital value between 0 to 1023. When this value is above 700 or below 300, it will transmit the code.<\/span><\/p>\n For any omnidirectional movement, the joystick is moved diagonally, “left-right-up-n-down.” Arduino will transmit four more codes for each of the four directional movements below.<\/p>\n The remote control transmits 12 + 8 = 20 different codes, including 12 codes for the robotic arm\u2019s movement and eight codes for the omnidirectional platform movement.<\/p>\n The robot’s control circuit operation<\/strong> The three dc motors move the robot forward and backward in eight different directions. The angles of the six servo motors are increased or decreased to achieve the full 6 DoF.<\/p>\n The HC12 module receives transmitted code from the remote control and sends it serially to Arduino. The code can be transmitted from a smartphone via Bluetooth, controlled through an Android app. The code is received by the HC05 module and sent serially to Arduino. The transmitted code is the same, regardless of whether it is sent from the remote control or a smartphone.<\/p>\n Arduino receives up to 20 different codes, such as W, A, D, X, Q, E, Z, C, P, O, I, U (provided in the above tables). When it receives the codes W, A, D, X, Q, E, Z, and C, (from the joystick), it moves the omnidirectional platform. When it receives the codes P, O, I, etc. (from the pushbuttons), it moves the robotic arm.<\/p>\n When code from the joystick is received to move the platform, Arduino will rotate the three dc motors forward and backward, according to the code from the omnidirectional platform.<\/p>\n\n
\n<\/strong>The robot is built using one circular wooden plate, three dc gear motors, and three omnidirectional wheels.<\/p>\n<\/a><\/p>\n\n
\n<\/strong>The robot system is made of two sections:<\/p>\n<\/a>\n
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\n<\/strong>The remote control circuit consists of Arduino NANO, the HC12 module, a joystick, pushbuttons, an LED, and a battery.<\/span><\/p>\n<\/a>\n
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<\/a>The circuit’s operation<\/strong><\/p>\n
\n<\/strong>The only function of the remote control is to transmit a specific code when any of the 12 buttons is pressed or the joystick is moved. When a button is pressed, the Arduino pin connects to the ground. The pin receives logic ‘0’ as an input, so Arduino detects that the button was pressed. Arduino then transmits one particular character as the code for each button pressed (see the table below).<\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n
\nThis circuit receives the code from the remote control or a smartphone via Bluetooth. It controls the movement of the omnidirectional platform and the robotic arm. It also controls the direction of the three dc motors and the angle of the six servo motors, based on the desired movement for the robot.<\/p>\n