Getting Parts for Your Project :: ECE 445 - Senior Design Laboratory

Getting Parts for Your Project

Student groups have a budget of $50 per student as of fall 2023. This money can be accessed through your TAs CFOP number. The ways parts can be sources are listed below in order of desirability.

1. Lab Kit

Each group is issued a locker and lab kit. A lab kit should include banana plugs and a breadboard.

2. ECEB 2070 Lab

There are many parts available for free in the ECEB 2070 lab such as THT passive components, MOSFETs, and line operated DC power supplies.

3. ECE 445 Inventory

Your TA can check out parts ECE 445 stores in white cabinets at the back of the lab: link. This inventory spreadsheet has not been updated in some time. There are items on this list that may not be in the cabinets and there are items in the cabinets that may not be on this list. Use this form for checkout: link

4. Electronics Services Shop (A.K.A. ECE Services Shop)

The Electronics Services Shop is located on the first floor of ECEB near the cargo elevator in ECEB 1041. They have a large stock of THT ICs (such as op-amps), potentiometers, motors, resistors, connectors, etc. Visit them when they are open to pick up parts.

Self-Service Inventory

Recently, they have started stocking 0805 surface mount passive components, crystal oscillators, microcontrollers, and linear regulators. The microcontroller portion of your board can probably be built entirely with parts from the Electronics Services Shop.  You do not need to pay for parts you obtain from the Electronics Services Shop.

SMD Component Inventory

To obtain parts from the e-shop, please contact your TA with a list. Your TA must email the e-shop and they will collect the parts. Your TA will get an email when the parts are ready. Your TA must pick up the parts from the e-shop . The e-shop will not release the parts to you.

SMD Parts Request Form

 

5. ECE Supply Center (A.K.A. ECE Store)

The ECE Supply Center is located on the first floor of ECEB in room 1031 near the loading dock. You must pay for parts out of pocket or with your TA's CFOP number. They stock breadboards, project boxes, jumper wires, THT LSI logic ICs, THT analog ICs, and more. This is a fantastic resource for building prototypes. You can search their catalog here: https://my.ece.illinois.edu/storeroom/catalog.asp.

6. Free Samples from Companies

It should be mentioned that companies many times are willing to provide small quantities of their products to students engaged in design projects. You might consider approaching the manufacturer directly, particularly regarding their newer products which they are interested in promoting. Don't count on success with this, but it has often been very useful.

7. MY.ECE Ordering (last resort)

You can order parts from amazon, digikey, mouser, etc. using the money provided to you by the course with your TA's CFOP number. Orders placed through this avenue must be approved by your TA through myECE. If you order multiple parts through digikey or mouser, please provide a shopping cart link. This method of ordering is best for parts that cannot be found in any of the sources listed above. This includes SMD MOSFETs, high performance ADCs/DACs, power converter ICs, SMD op amps, modem ICs, etc. Please refer to this tutorial for more instructions: http://courses.engr.illinois.edu/ece445/lab/resources/ece_purchasing_app_tutorial.pdf

Personal Purchases

It is always possible and encouraged to purchase your own parts from a local store (Radio Shack, Best Buy, etc.) or order them from online vendors. Personal purchases will not be reimbursed by the department.

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

Business Office

If none of these methods work, you can go through the business office with the help of your TA.