Project :: ECE 445 - Senior Design Laboratory

Project

#	Title	Team Members	TA	Documents	Sponsor
39	Robotic T-shirt Launcher Mark III	Jiakai Zheng Mingchen Li Shenao Wang Xiao Luo		design_document1.pdf proposal1.pdf proposal2.pdf	Timothy Lee
	## Team Members Li Mingchen (ml110), Zheng Jiakai (jiakaiz4), Wang Shenao (shenaow2), Luo Xiao (xiaoluo5) ## Project Title Robotic T-shirt Launcher Mark III ## Problem 1.The previous version of MARK II is excessively bulky for convenient portability and usage. It is imperative to reduce the dimensions and weight of the T-shirt launcher. 2.The shirt launcher is equipped with insufficient spare ammunition. It is necessary to ensure a minimum of three shots or enhance its firing rate. 3.To address system uncertainties, a comprehensive risk assessment should be conducted during the design phase to identify potential sources of uncertainty and their potential impacts. Mitigation strategies, such as redundant safety mechanisms, backup systems, and robust testing procedures, can be incorporated to minimize the effects of uncertainty on the system's performance and reliability. ## Solution Overview While preserving the achievements of ROBOTIC's T-SHIRT LAUNCHER MARK II, our team will address critical flaws. For example, the MARK II was too large and heavy for its function, and the MARK II fired too slowly. In addition, in terms of automation of the system, we will also try to achieve the unfinished goals of the MARK II and ensure safety by optimizing the launch trajectory. ## Solution Components Launcher system: The launcher system consists of an air chamber made up of gas cylinders, gas cylinders used to inflate the air chamber, an inlet valve, an exhaust valve, an exhaust trigger, and a barometer (for detecting the air pressure in the air chamber). These components are used to rapidly inflate and launch the T shirt through differential air pressure. Two Degree of Freedom Targeting Gimbal: This targeting gimbal consists of a stepper motor, reduction gear sets and aluminum frame structures. It consists of two degrees of freedom of motion, which enables precise control of the pitch and horizontal rotation angles in a stable manner while achieving light weight. The purpose is to adjust the position of the launcher in 3D space after receiving electrical signals from the control system so that the T-Shirt can be successfully launched to the desired place. Control System: The Control System plays a crucial role in efficiently managing the components of the system. It encompasses a gimbal controller, actuator controllers, electromagnetic valves, and a microcontroller like Arduino. They work together to ensure smooth and accurate operations, control the release of compressed air and keep the pressure in safe operating limits. Automation System: For the case of use on the gimbal, we want the launcher to be able to fire automatically. Therefore, the system should have a suitable function to automatically adjust the direction and force of the launch according to the situation. In addition, for safety reasons, the system will include a computer vision module to conduct spectator behaviour recognition to avoid potential accidents, such as stampedes. ## Criterion for Success Functionality of Launcher: The launcher should be able to fire T-shirts. The force of the launch can be changed by controlling the air pressure inside the launcher at the time of launch. The system should be able to simplify the operation by pre-loading the T-shirt in a certain amount. The operator can easily operate the transmitter with the trigger. Firing Rate: The launcher should have a relatively fast firing rate, which is determined by three key factors: the rate at which the gas chamber inflates to reach the desired pressure, the rate at which the controller controls the closing and opening of the valves, and the rate at which the T-Shirt bullet is loaded. The desired pressure of the chamber will determine the force of the shot, which can be controlled by adjusting the valve closing time, and the chamber will be equipped with a barometer to allow the operator to accurately control the force of the shot and make adjustments. Smaller Size and Weight: Reducing size and weight was one of the main objectives of this MARK III design, and for this reason we abandoned the rotary round change design of the MARK II and adopted a loaded round change design to reduce redundant size. Secondly, the weight of the gas chamber will be reduced. Two large gas cylinders are used in the MARK II, and in fact, the small volume of a single cylinder provides gas that is perfectly adequate for firing at least 40 rounds of ammunition. Then there is the reduction of overall size and weight, which is achieved by simplifying the frame design of the transport vehicle, and the overall size of the launcher. Safety: Since the launcher uses a pressure vessel, security considerations are very important to the system. The key parts of the launcher must have components to detect safety metrics, such as barometric values. In addition, for accidents that may occur during use, we should take into account and design safety mechanisms. ## Distribution of Work Li Mingchen: Automation System Zheng Jiakai: Launcher system Wang Shenao: Targeting Gimbal System Luo Xiao: Control System

Title

Team Members

Documents

Sponsor

Robotic T-shirt Launcher Mark III

Jiakai Zheng
Mingchen Li
Shenao Wang
Xiao Luo

design_document1.pdf
proposal1.pdf
proposal2.pdf

Timothy Lee

## Team Members
Li Mingchen (ml110),
Zheng Jiakai (jiakaiz4),
Wang Shenao (shenaow2),
Luo Xiao (xiaoluo5)

## Project Title
**Robotic T-shirt Launcher Mark III**

## Problem
1.The previous version of MARK II is excessively bulky for convenient portability and usage. It is imperative to reduce the dimensions and weight of the T-shirt launcher.

2.The shirt launcher is equipped with insufficient spare ammunition. It is necessary to ensure a minimum of three shots or enhance its firing rate.

3.To address system uncertainties, a comprehensive risk assessment should be conducted during the design phase to identify potential sources of uncertainty and their potential impacts. Mitigation strategies, such as redundant safety mechanisms, backup systems, and robust testing procedures, can be incorporated to minimize the effects of uncertainty on the system's performance and reliability.

## Solution Overview
While preserving the achievements of ROBOTIC's T-SHIRT LAUNCHER MARK II, our team will address critical flaws. For example, the MARK II was too large and heavy for its function, and the MARK II fired too slowly. In addition, in terms of automation of the system, we will also try to achieve the unfinished goals of the MARK II and ensure safety by optimizing the launch trajectory.

## Solution Components
Launcher system: The launcher system consists of an air chamber made up of gas cylinders, gas cylinders used to inflate the air chamber, an inlet valve, an exhaust valve, an exhaust trigger, and a barometer (for detecting the air pressure in the air chamber). These components are used to rapidly inflate and launch the T shirt through differential air pressure.

Two Degree of Freedom Targeting Gimbal: This targeting gimbal consists of a stepper motor, reduction gear sets and aluminum frame structures. It consists of two degrees of freedom of motion, which enables precise control of the pitch and horizontal rotation angles in a stable manner while achieving light weight. The purpose is to adjust the position of the launcher in 3D space after receiving electrical signals from the control system so that the T-Shirt can be successfully launched to the desired place.

Control System: The Control System plays a crucial role in efficiently managing the components of the system. It encompasses a gimbal controller, actuator controllers, electromagnetic valves, and a microcontroller like Arduino. They work together to ensure smooth and accurate operations, control the release of compressed air and keep the pressure in safe operating limits.

Automation System: For the case of use on the gimbal, we want the launcher to be able to fire automatically. Therefore, the system should have a suitable function to automatically adjust the direction and force of the launch according to the situation. In addition, for safety reasons, the system will include a computer vision module to conduct spectator behaviour recognition to avoid potential accidents, such as stampedes.

## Criterion for Success
Functionality of Launcher: The launcher should be able to fire T-shirts. The force of the launch can be changed by controlling the air pressure inside the launcher at the time of launch. The system should be able to simplify the operation by pre-loading the T-shirt in a certain amount. The operator can easily operate the transmitter with the trigger.

Firing Rate: The launcher should have a relatively fast firing rate, which is determined by three key factors: the rate at which the gas chamber inflates to reach the desired pressure, the rate at which the controller controls the closing and opening of the valves, and the rate at which the T-Shirt bullet is loaded. The desired pressure of the chamber will determine the force of the shot, which can be controlled by adjusting the valve closing time, and the chamber will be equipped with a barometer to allow the operator to accurately control the force of the shot and make adjustments.

Smaller Size and Weight: Reducing size and weight was one of the main objectives of this MARK III design, and for this reason we abandoned the rotary round change design of the MARK II and adopted a loaded round change design to reduce redundant size. Secondly, the weight of the gas chamber will be reduced. Two large gas cylinders are used in the MARK II, and in fact, the small volume of a single cylinder provides gas that is perfectly adequate for firing at least 40 rounds of ammunition. Then there is the reduction of overall size and weight, which is achieved by simplifying the frame design of the transport vehicle, and the overall size of the launcher.

Safety: Since the launcher uses a pressure vessel, security considerations are very important to the system. The key parts of the launcher must have components to detect safety metrics, such as barometric values. In addition, for accidents that may occur during use, we should take into account and design safety mechanisms.

## Distribution of Work

Li Mingchen: Automation System

Zheng Jiakai: Launcher system

Wang Shenao: Targeting Gimbal System

Luo Xiao: Control System

Featured Project

# Wireless Charging Table Supporting Multiple Devices with Arbitrary Placement

# Problem

While more and more device manufacturers adopt wireless charging into their smartphones and headphones, most currently available wireless charging pads only support a single device and require strict alignment between the device and the coil. Misalignment can negatively influence both user experience and charging efficiency. In certain scenarios such as cafeterias, a table that can simultaneously charge multiple devices with arbitrary placement can be useful and COOL, allowing the users to sit wherever they like and to arbitrarily place their devices.

# Solution Overview

We intend to design and manufacture a table with multiple mobile coils placed in an intermediate layer below. Driven by step motors, a tool grabber attaches the coils using electromagnets and drop them in the right place. Computer vision will be used to recognize devices (phones, AirPods, etc.) and guide the chargers to corresponding locations. Once the coil is in place, it will first communicate with the device (Qi protocol) to verify whether the device can be charged wirelessly. If yes, the charging process will start. Otherwise, the coil will be moved back to its original location. The scheduling algorithm ensures the wires get separated and neat.

# Solution Components

* Mechanical subsystem. The main moving component of the system is a large-scale X-Y moving mechanism under the table. The coils will be placed between two panels above the moving mechanism and will be caught and dropped to the right place by the moving tool head. The tool head will be developed with electromagnets or magnets with Z-axis moving capability.

![sketch](https://courses.grainger.illinois.edu/ece445zjui/pace/getfile/18618)

* Vision detection subsystem. This includes a camera and a processing unit. It detects the locations of phones and other chargeable devices and send their positions to the control unit. In real-world settings, pre-installed surveillance cameras may be used as the video source so that no additional camera is required. Embedded GPU (NVIDIA Jetson Nano as a candidate) or cloud service can be used for image processing.

* Power supply control. It is used to control wireless chargers and supply power to devices if and only if the handshake between charger and device is successful. Status will be reported to the central control unit.

* Central control unit and embedded software. According to the output given by the vision detection system or the feedback from the power supply system, the central control unit should move the chargers with proper scheduling algorithm to pair chargers with devices and keep wires of coil separated and neat.

# Criterion for Success

* The vision detection system can localize chargeable device at an accuracy of over 80% and response within 2s.

* The power system can supply powers when a chargeable device is present, and not supply power when the misdetection happens. Correct feedback can be sent to the central control system.

* The mechanical system moves correctly according to the commands given by the central control system.

* The central control system can send correct commands to the mechanical system given the position information from the vision system and the feedback from the power supply system. It should be able to keep wires of charging coil separated.

# Evaluations on Alternative Solutions

The technology of wireless charging emerged some time ago, but its inclusion in commercial devices doesn’t take off until recent years. Intuitively, wireless charging doesn’t bring much additional convenience compared to the wired charging, but its adoption by major manufacturers has proven its value. Similarly, in certain settings such as the cafeteria, charging without alignment may significantly increase user experience, comparing to having only a few fixed charging locations.

An alternative solution to enable table-scale wireless charging is to deploy multiple coils covering the whole table. But it doesn’t solve the alignment problem unless the coils are heavily overlapped, which has been proven to be difficult by already canceled Apple AirPower.