"AKIRA" Desktop Serial Robotic Arm:
"AKIRA" Desktop Serial Robotic Arm:
CAD software used: Autodesk Inventor 2018.
Download Scope: 3D CAD model (Autodesk Inventor files), STEP.
"AKIRA" is a designed model for a desktop robotic arm. It is a serial robot with an open kinematic chain that has four and a half degrees of freedom, all of which are rational. This robot is classified as one of the pick and place robots. Regarding the mechanical aspect, the robot excels in its simple design. In its motion, it depends on a group of motors connected either directly or indirectly to the motion axes relevant to each link of the arm. Besides, five small-sized servo motors are used, and they rotate an incomplete rotation. There are three motors that have an angle of rotation equal to 200 degrees, and there are two motors that have an angle of rotation equal to 180 degrees. One servo motor is assembled to each axis of the motion axes (for each degree of freedom, we need one actuator). The last motor is used to achieve the operation of opening and closing for the actuator head, which is a mechanical gripper.
"AKIRA" robot consists of a rotational base that represents the first axis of the robot, and it can rotate 180 degrees. The first link connected to the base represents the second axis of the robot, and it can rotate a maximum of 130 degrees. The second link, which is connected to the first one, represents the third axis of the robot, and it can rotate to a maximum of 130 degrees as well. Regarding the actuator head of the robot, it represents the fourth axis and can rotate around its vertical axis 180 degrees. Thus, the actuator head acquires an additional degree of freedom besides those resulting from the previous three axes. Consequently, the robot has four degrees of freedom (DOF). Regarding the rest half degree of freedom, it is a metaphorical expression that describes the ability of the actuator head holder part of the robot to rotate in a way that guarantees the vertical position between the actuator head axis and the work plane. This can be achieved through the three linked parallelism mechanisms found on the left side of the robot.
The robot has five servo motors, as said beforehand. Three of them can rotate 60 degrees in 0.18 seconds when run at 6 volts. They can rotate the same angle but in 0.23 seconds when run at 4.8 volts. The motor's torque according to these feeding voltages is (4.4-5.5) kg.cm. The other two motors can rotate 60 degrees in 0.1 seconds when run at 5 volts, and the torque of each of them is equal to 1.8 kg.cm. Each rotation axis has one motor. The fifth motor is used to move the gripper's jaws in opening and closing operations. The mechanical mechanism of the gripper is based on a pair of assembled mated spur gears. One of them is the leader gear, which is connected to the motor's axis by a mechanical mechanism of two links to ensure the gripper's mission of opening and closing as a result of conveying the rotational motion from the motor to the leader gear through this mechanism. The maximum angle that the gripper can open is 40 degrees. The servo motors are connected to a microcontroller system consisting of a servo motor controller from the type of Maestro Micro 6, manufactured by Pololu Robotics & Electronics. This controller can control up to six servo motors, and just five ports have been used in this robot. The servo motors controller is connected to an UNO type Aurduino controller.
"AKIRA" robot can be controlled and programmed directly by a computer after connecting it to the servo motors controller and the Arduino controller through their inlets. The workspace of the robot is shown as a schematic form with the attached photos.