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The engineering of the body!

Third & Final Design

The third design of the project was created following new instructions, the main objective was shifted towards creating a pan & tilt devices. Also trying to resolve the issue that was found in prototype two; the M1 from schematics 2-1 of the second design. It will either be set in front of M0, which would required a worm gear set to change the direction of motion, or the M1 will have to be placed in one of the sides, disproportioning the device’s arm, see image below.

Prototype II 180º

Mechanical design III

This design is trying to solve the issues encountered in the last two designs and trying to develop the device that would be used for pan & tilt movement. It could still be used for testing devices if required by implementing the algorithm in the microcontroller. The device will have the same number of actuators as it can be appreciated in schematics 2-2. M1 and M2 have changed their position to reduce the distance of the arm L1 and facilitate the two axes movement. M0 will rotate the base creating 360º of movement (pan) and M1 will rotate the gripper 180º (tilt). For the project, 3mm thick black Perspex will be used and will be cut in the laser cutter.

P&T Devices1P&T Devices2P&T Devices3

P&T Devices CADP&T Devices1 cad2

The prototype from design I and design II were created using thin cardboard and the models required some adjustments since was less than 3mm thick. Image above shows the final prototype. In the top right image, it can be appreciated the attachment added to the gripper to hold a small webcam.

 

Base of Prototype III

The base of the device will hold the circuit for control and power supply; ideally, it will have a single PCB containing all the necessary components. Two levels containing different parts of the circuit were used instead, as seen in image on the left.

  • Level one; contains the microcontroller PCB for testing.
  • Level two; contains the power supplier and two stepper motor drivers.

Second Design

The device has been designed using cad software, Solidworks. The different parts, which will be cut in the laser cutter, are restricted to be two-dimensional.

Below, it is the first sketch of the robot-arm. This first sketch was designed to use two motors, one to control the vertical movement 180º and another of 360º to create a circular rotation for the gripper and had the possibility to have another motor in the base of 360º. The main objective was only to test two of the three axes of the accelerometer. This was the reason for deciding to use only two DOF.

robot1

 

 

The second design was created for trying to solve some previous issues. This design is taking in consideration the proximity of the gripper L1 and L2 and also its weight W1 and W2. The second design had the gripper closer to the base; this has multiple connections to attach equipment to it,  like small PCB or the accelerometer see below.


Robot-Art II           |mechanical design II

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The M0 motor is attached to the side of the base and it creates the 360º movement. The base needs a metal platform to support all the weight of the arm and M1 motor. This motor will have 180º of movement.