Project

# Title Team Members TA Documents Sponsor
13 Sun Tracking Umbrella
 Dora Stavenger
Megan Cubiss
Sarah Wilson
 Wesley Pang design_document1.pdf
final_paper3.pdf
photo1.png
presentation1.pdf
proposal1.pdf
video
Team Members
- Dora Stavenger (doraas2)
- Sarah Wilson (sarahw7)
- Megan Cubiss (mcubiss2)

Problem

When sitting outside in urban third spaces, it is often too hot or bright to stay there for a while. Even at low temperatures, exposure in direct sun gets uncomfortable and/or unhealthy quick. Many outdoor spaces do have stationary umbrellas but, once set, they only help for a period of time which can lead to discomfort from excessive heat/brightness. This can be avoided by adjusting the umbrella throughout the day but they are often quite heavy and hard to maneuver.

Solution Overview

To solve this problem, we suggest an umbrella that tracks the position of the sun using solar panels in addition to other sensors and adjusts the tilt of the umbrella to provide UV protection for the user and ensure comfort. To prove out this concept we are proposing to make a smaller model of an umbrella, using resources from the machine shop as well as doing some design ourselves. We will also do the math to prove that our design could be scaled up and withstand the extra load from the heavier weight of a real umbrella.

Solution Subsystems

##Subsystem 1: Model Umbrella

This subsystem is the mechanical basis for the project:
The canopy would be scaled to about that of a personal rain umbrella.
The rain umbrella would attach to an elbow joint allowing for tilting motion.
The base would attach to a stable plate and a bearing allowing for circular motion.

##Subsystem 2: Solar Cells / Brightness Sensors

This subsystem would be responsible for powering the umbrella as well as provide data on light intensity.
A ring of solar cells towards the widest portion of the umbrella as well as solar cells towards the top.
Solar cells power moving mechanisms as well as provide backup power through battery storage.
Light intensity is measured using these solar cells to determine optimal positioning.

##Subsystem 3: Motor for Solar Angle Tracking

This subsystem would be responsible for tilting the canopy of the umbrella:
A stepper motor would be used due to low speed, high torque application.
Physical stop built in for added safety so the canopy does not fall.
Motor control done using H-bridge.

##Subsystem 4: Motor for Solar Position Tracking

This subsystem would be responsible for rotating the entire umbrella:
A stepper motor would be used in order to keep design consistent.
Motor control done using separate H-bridge from Subsystem 3.

##Subsystem 5: wifi/bluetooth/communication

This subsystem is responsible for the communication between the physical device on the umbrella and a user’s phone/application. Using a ESP32, a web server can be established which can be connected to a laptop/display via the existing wifi abilities. This would allow two way data communication where data could be viewed in a simple web browser with some sort of user interface to allow commands to be pushed back to the microcontroller. This would also allow users on the same network to access the page and interact with the device.

Criterion for Success

Outcomes :
A scaled version of the working product with the proof that it is scalable to a full sized version. The umbrella tilts based on differences in intensity detected by the solar cells. The umbrella is structurally sound and does not fall over during any motion. Data from the solar cell is displayed and user input is possible.

Hardware :
The device does not get in the way of user experience.
Solar cells send accurate data to software components.
Motors respond accordingly to change umbrella positioning.

Software :
Data from solar cells are accurately received and processed by software.
Software to determine how umbrella positioning is to move for optimal coverage.
Accurately disperses information for motor movement.

WHEELED-LEGGED BALANCING ROBOT

Gabriel Gao, Jerry Wang, Zehao Yuan

WHEELED-LEGGED BALANCING ROBOT

Featured Project

# WHEELED-LEGGED BALANCING ROBOT

## Team Members:

- Gabriel Gao (ngao4)

- Zehao Yuan (zehaoy2)

- Jerry Wang (runxuan6)

# Problem

The motivation for this project arises from the limitations inherent in conventional wheeled delivery robots, which predominantly feature a four-wheel chassis. This design restricts their ability to navigate terrains with obstacles, bumps, and stairs—common features in urban environments. A wheel-legged balancing robot, on the other hand, can effortlessly overcome such challenges, making it a particularly promising solution for delivery services.

# Solution

The primary objective of this phase of the project is to demonstrate that a single leg of the robot can successfully bear weight and function as an electronic suspension system. Achieving this will lay the foundation for the subsequent development of the full robot.

# Solution Components

## Subsystem 1. Hybrid Mobility Module:

Actuated Legs: Four actuator motors (DM-J4310-2EC) power the legged system, enabling the robot to navigate uneven surfaces, obstacles, and stairs. The legs also functions as an advanced electromagnetic suspension system, quickly adjusting damping and stiffness to ensure a stable and level platform.

Wheeled Drive: Two direct drive BLDC (M3508) motors propel the wheels, enabling efficient travel on flat terrains.

**Note: 4xDM4310s and 2xM3508 motor can be borrow from RSO: Illini Robomaster** - [Image of Motors on campus](https://github.com/ngao4/Wheel_Legged_Robot/blob/main/image/motors.jpg)

The DM4310 has a built in ESC with CAN bus and double absolute encoder, able to provide 4 nm continuous torque. This torque allows the robot or the leg system to act as suspension system and carry enough weight for further application. M3508 also has ESC available in the lab, it is an FOC ESC with CAN bus communication. So in this project we are not focusing on motor driver parts. The motors would communicate with STM32 through CAN bus with about 1 kHz rate.

## Subsystem 2. Central Control Unit and PCB:

An STM32F103 microcontroller acts as the brain of the robot, processing input from the IMU through SPI signal, directing the motors through CAN bus. The pcb includes STM32F103 chip, BMI088 imu, power supply parts and also sbus remote control signal inverter.

Might further upgrade to STM32F407 if needed.

Attitude Sensing: A 6-axis IMU (BMI088) continuously monitors the robot's orientation and motion, facilitating real-time adjustments to ensure stability and correct navigation. The BMI088 would be part of the PCB component.

## Subsystem 3. Testing Platform

The leg will be connected to a harness as shown in this [sketch](https://github.com/ngao4/Wheel_Legged_Robot/blob/main/image/sketch.jpg). The harness simplifies the model by restricting the robot’s motion in the Y-axis, while retaining the freedom for the robot to move on the X-axis and jump in the Z-axis. The harness also guarantees safety as it prevents the robot from moving outside its limit.

## Subsystem 4. Payload Compartment (3D-printed):

A designated section to securely hold and transport items, ensuring that they are protected from disturbances during transit. We will add weights to test the maximum payload of the robot.

## Subsystem 5. Remote Controller:

A 2.4 GHz RC sbus remote controller will be used to control the robot. This hand-held device provides real-time control, making it simple for us to operate the robot at various distances. Safety is ensured as we can set a switch as a kill switch to shutdown the robot in emergency conditions.

**Note: Remote controller model: DJI DT7, can be borrow from RSO: Illini Robomaster**

The remote controller set comes with a receiver, the output is sbus signal which is commonly used in RC control. We would add an inverter circuit on pcb allowing the sbus signal to be read by STM32.

Note: When only demoing the leg function, the RC controller may not be used.

## Subsystem 6. Power System

We are considering a 6s (24V) Lithium Battery to power the robot. An alternative solution is to power the robot through a power supply using a pair of long wires.

# Criterion For Success

**Stable Balancing:** The robot (leg) should maintain its balance in a variety of situations, both static (when stationary) and dynamic (when moving).

**Cargo Carriage:** The robot(leg) can be able to carry a specified weight (like 1lb) without compromising its balance or ability to move.

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**If we are able to test the leg and function normally before midterm, we would try to build the whole wheel legged balancing robot out. It would be able to complete the following :**

**Directional Movement:** Via remote control, the robot should move precisely in the desired direction(up and down), showcasing smooth accelerations, decelerations, and turns.

**Platform Leveling:** Even when navigating slopes or uneven terrains, the robot should consistently ensure that its platform remains flat, preserving the integrity of the cargo it carries. Any tilt should be minimized, ideally maintaining a platform angle variation within a range of 10 degrees or less from the horizontal.

**Position Retention:** In the event of disruptions like pushes or kicks, the robot should make efforts to return to its original location or at least resist being moved too far off its original position.

**Safety:** During its operations, the robot should not pose a danger to its surroundings, ensuring controlled movements, especially when correcting its balance or position. The robot should be able to shut down (safety mode) by remote control.

Project Videos