The goal of this project is to develop a an arduino based autonomous construction robot that builds structures according to the desired specifications given by the user through a human interface. Here we present a hardware system and high-level control scheme for autonomous construction of 3D structures. The hardware comprises a mobile robot and specialized passive blocks; the robot is able to manipulate blocks to build desired structures and can maneuver on these structures. We describe and evaluate the construction robot’s key capabilities of climbing, navigation, manipulation and demonstrate its ability to perform complex tasks that combine these capabilities.
Basic Introduction to Autonomous Construction Robot
The name tells you the story, Autonomous construction robot is a self-fabricated robot which functionally will construct a wall. The shape of the robot is designed that it will carry a single brick and carry it to the desired position, rest on it and follow a staircase algorithm. This reduces the load on the servo motor which make the gripper to work. The overall body is of aluminum to make sure the robot is light-weight and can maneuver freely.
Wheels of robot are whegs because the robot achieves its objectives by climbing over the bricks and placing over it.
Analysis and Design of Construction Robot
This section will give you thorough insight into modules of project. And proper functionality with the required bits of calculations.
Design of the body
After simulations on Solid Works the design of the body is semi-circle in shape. The body is of Aluminum to reduce its weight and achieve better results. The body has a raised arch in the middle so that it could clear any hindrance or collision. Another reason for the arch shape in the middle is to achieve stability while its weight is on the center of gravity. The brick is elevated with the help of a worm-gear motor which was attached to a claw. Servo motors is used to grasp the brick with a claw. Worm gear was a selection because of its conservation of energy.
Design of the wheels
As the robot is going to climb a brick so it cannot grip on the surface. Due to this reason we had to design a special wheels, which are termed as whegs, to accomplish this task. The idea of the Whegs are taken from “Termes” with a little modification. Whegs has three arms, each having a hook shaped edges on either side of the arm. Every arm is 120 degrees apart from the other one. The idea is to move robot smoothly and help it climb efficiently. The Whegs structure is designed with the help of Solid works.
Selection of Motors for Autonomous Construction Robot
The demand of project is high torque and precision. Stepper motors for their high precision were used but with distinguishing degree of rotation with each step.
NEMA 17 stepper motor having a rating of 1.8-degree rotation/step, 2.5V, and 1.8A was selected for the project. Four motors attached with a respective wheg allowing high torque traversing and to avoid stalling.
Design of Claw
Calculations for the right motor which can provide enough torque to lift a brick using the gripper are below:
Following equation shows the moment of a force:
Moment=force(N)*distance from pivot (cm or m) T=Force*length
With the help of these formulas we calculated the required of the motor to be 17kg-cm.
Selection of Brick
Bricks are ideally of polymer which are too light weight. However, in case of inaccessibility of the polymer injection a material Jumbo Lon is to be used.