Team Salem - ECE44x Project 19

The Original Electric Powered Wheelbarrow

Team Salem’s project is to design and build an electric powered wheelbarrow. The reason for creating a power assisted wheelbarrow is to hone our skills with power electronics, motor control, and user interfaces. The final product benefits landscaping companies, yard work enthusiasts, and people who are generally not very strong. The electric wheelbarrow features motor assistance to help the user push the load, automated load dumping, anti-slip control, a user interface, and a display. For this project, a regular wheelbarrow is used as a structural base. The electric motor is positioned as the hub by using an in-hub DC motor to drive the wheel. The battery resides under the bucket of the wheelbarrow, behind the motor, and is removable for easy changing. The wheelbarrow is modified for motor placement, battery placement, and the circuitry. The dumping interface tilts the bucket up by approximately 45 degrees from its resting position and thus assists the user in dumping the wheelbarrow. The wheelbarrow has an anti-slip system that detects wheel slippage during motor assistance and keeps the motor corrected. The interface will be positioned at the top of the handles and have a display for battery level and speed. Most of the circuitry for the wheelbarrow is located under the user interface. This includes the motor controller, the power electronics that deliver different voltage levels to the driving motor, the automated load dumping circuitry, the microcontroller, and the display controller. The goal for the charge time of the battery is less than six hours with a changeable battery lasting an hour of use per charge. This is a small scale project, but if the demand for this product gets fairly large, it could be a feasible product to carry in large stores such as Home Depot or Lowes.

After talking to some yard work enthusiasts and some of the Construction Engineering Management majors at OSU, this list of requirements was created:

• The motor must pull a significant load. The electric wheelbarrow must be functional. It is not useful if it cannot carry a significant load. It must be able to carry more of a load than a regular wheelbarrow.

• Motor assisted operation must be safe. No powered piece of machinery would be sold if it did not meet rigorous safety requirements, but more importantly, it needs to look like its safe to the customer. Redundancy interlocks are needed to protect the user from damaging him or herself and convince the user that they make the device completely safe.

• Operation must be easy. The electric wheelbarrow needs to look easier than a standard wheelbarrow to operate. It needs to function efficiently with motor assistance forward and without motor assistance in both forward and reverse directions. Extremely easy and intuitive controls will make transporting loads go from a chore to a privilege.

• The completed device must not be heavy. It is important that the product acts like a regular wheelbarrow with similar weight and agility so that it does not appear cumbersome. An unwieldy device is an unwanted device and that is to be avoided.

• Maintenance must be simple. No customer would buy a product that required extended or skilled work to upkeep when a simpler design would be satisfactory. It must not take an engineer to keep up and running; an adult should be able to maintain it.

• The battery must swap easily. It is never acceptable for powered tools to not have replaceable batteries. Nothing is less desirable than having to stop use of a tool to wait for it to recharge. The process for changing out the battery for a spare needs to be easy enough for a weak user to do quickly without causing damage to themselves or the wheelbarrow.

• The wheelbarrow must have a good battery life. Regardless of how easy it is to replace the battery, operation of the wheelbarrow must not be interrupted often by battery life restrictions. Customers need to be reassured that the device provides great benefits without causing work.

• The electronics must be robust. The electric wheelbarrow must endure wear and tear the same way a regular wheelbarrow does. No electronics can be exposed to environmental conditions; it must be waterproof. The electronics must be able to outlast the standard wheelbarrow components from extended use.

• The wheelbarrow must be visually appealing. An ingenious product goes unwanted if the customer does not like how it appears. The electric wheelbarrow must give off an appealing appearance that says, "I'm the Harley Davidson of wheelbarrows, without the cost."

We are an unsponsored team.

Team Salem

Left to Right:
Mike Nordhill - nordhilm@onid.orst.edu
David Fossholm - fosshold@onid.orst.edu
Joey Stoenner - stoennej@onid.orst.edu

Website Contents

1. Project Overview
   
2. Background Research
   
3. System Requirements and Desired Features
   
4. Design Solutions
   
5. Top Level Block Design
   
   1. Chassis
      
   2. Motor Assistance
      
   3. Load Dumping
      
   4. Display
      
   5. User Interface
      
   6. Control Code
      
   7. Regulator 48Vin 12Vout
      
   8. Regulator 12Vin 3.3Vout
      
   9. Microcontroller
      
   10. Battery Box
       
   11. Battery Charger
       
   12. Speed Sensor/Slip Detection
       
   13. Keyswitch
       
   14. Motor
       
   15. Worklight
       
6. Testing
   
7. Project Timeline
   
8. System Test Evidence
   
9. Expo Materials
   

Project Video

References

• Signed Contract.pdf