System Implementation

Sensors Laboratory

At the beginning of the semester the team focused on testing the different sensors that could potentially be used throughout the semester. Here we worked with ultrasonic sensors, infrared sensors, potentiometer, and limit switches. Through this lab, we determined that using ultrasonic sensors for our robot's localization would be the best method, given their high level of accuracy and how relatively easy they are to implement.

DC Motor, Stepper Motor, Servo Motor Laboratory

The motor lab our team was exposed to several different types of motors. Through this lab we became aware of each motor type's limitations and abilities, as well as how to control their physical outputs such as rotational speed and applied torque. This lab also required sensor control of motors, so here we began initial practice interfacing sensors with motor systems, something we would use heavily in our final design.

Cardboard Model of First Mock Up

For our first demonstration a cardboard model mock up was built in order to showcase the idea that our team had. This first physical mock up was a great way for our team to start planning how our proposed systems would interact.

First System Integration (1D)

The first iteration of our robot included one linear actuator. This design simply proved the idea of stepping with a linear actuator. In the design review this first system integration was made for we demonstrated on a horizontal surface how our robot would inch-worm, switching suction from cup system to cup system and back again.

Second System Integration CAD

This second iteration of the 3D Model represent the first complete idea of having two linear actuators connected together. This would allow for stepping in the horizontal and vertical directions. This CAD model also shows our first iteration of our stepping system that would raise and lower our vacuum cup systems. Also modeled here is our rough plan for our first cleaning system that used both a microfiber sponge and a squeegee tethered together.

Pneumatic System to Generate Vacuum Pressure

The next step was to make our system work, and for this we needed a pneumatic system. This first pneumatic system utilized two two-way solenoid valves per cup system to both expose its cups to a vacuum and release those cups from the window with applied atmospheric pressure. This first system was controlled with two motor drivers and an Arduino unit.

1-DOF Walking on Vertical Surface Prototype

Once we created our first iteration of a pneumatic circuit, we were able to attach vacuum lines to our 1D prototype and demonstrate a horizontal walking motion on a vertical surface. This first fully integrated system was a huge step for us, because it proved our idea of switching vacuum between cup systems and strategically driving a linear actuator could locomote us across a vertical surface.

Rack and Pinion Stepping System Prototype First Iteration

The first iteration of the rack and pinion system shown on the left. Using the CAD models we created earlier we prototypes this first stepping system with just vacuum cups. Using this first prototype we were able to start planning the motor driving logic that would allow us to create a smooth and well planned step.

Integrated Cleaning System First Iteration

The cleaning system first iteration consists of adding a long rectangular piece of cloth that will be pressed against the window. The pressure will be given by the springs as seen on the figure on the right. We also fixed a squeegee to the back of the cleaning pad to rid the board of any excess moisture left behind by the cleaning pad. With this first cleaning system prototype we were also able to test the best cleaning solution mixture to clean the window.

2-DOF Walking on Horizontal Surface Prototype

This system is the first one that include the two linear actuator together as seen on the earlier 3D model prototypes. With this second linear actuator we were able to begin planning and testing our 2D walking motion that would move us both across and up and down the window.

Rack and Pinion Stepping System Second Iteration

Our second iteration of the stepping system consisted of two opposing rack systems that would tie the motion of the cleaning system and vacuum cups together, so that when the vacuum cups were being raised, the cleaning pad would be lowered to the window surface, and when the pads were raised off the window, the cups would lower to it. This new dual motion allowed our robot to stick to the window with the cups without interference from the cleaning pads, while also cleaning without interference of the vacuum cups.

Cleaning System- Second Iteration: Irrigation System

For the second iteration of the cleaning system, a passive spritzer system was designed and prototyped. The picture shown on the left shows the prototyped system that has a large cleaning solution reservoir at the base and small distribution holes along the extrusion that allow cleaning solution to re-moisten the cleaning pads during a cleaning pass of the window.

2-DOF Walking on Vertical Surface Prototype

To the left is the full 2D walking and barrier stepping prototype. With fully integrated vacuum lines and stepping systems this prototype was able to move across the window's surface and over the barrier, a great step for our team. While walking and stepping is fully integrated here, the cleaning systems are still absent, as well as the PCB. This system preformed fairly well at its particular design review, only needing new pneumatic lines and simplified logic controls to function perfectly.

Final System Design

This is the final system presented for the two final system demos. With fully integrated cleaning systems and associated bracing this system cleaned the window well. Other notable features about this final design are the four ultrasonic sensors that provide the necessary values to localize the robot, the motor driver and PCB that are mounted on the robot's frame, and the more robust stepping system that functions more effectively with less system failures.

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