RTV 1120 EV

Background

Tracks and Wheels is a designer, manufacturer and distributor of heavy equipment for the mining and construction industries. Recent advances in technology have caused battery power to become a viable alternative to diesel engines for vehicles and Tracks and Wheels is eager to remain at the forefront of mobile mining vehicle technology. Therefore, the company converted a Kubota RTV-x1120 diesel vehicle to be battery operated. However, this project was abandoned at an incomplete state and needed to be pushed forward from an engineering perspective, as well as a product perspective.

Goals

The goal of the MineMaster RTV EV project, when introduced to me, was to improve the vehicle to the point of a finished prototype, which could be reproduced easily based on engineering drawings. The vehicle needed to be reconstructed and examined from the ground up in order to produce a product out of the prototype.

Tools and Technologies

• Sketch
• AutoCAD
• CODESYS

Solution and Process

I was aware of the project since its inception; however, my official introduction to the prototype was abrupt, I was told where the vehicle sat in the shop and I went to inspect the machine. The initial investigation was from an engineering perspective. Questions of component functionality, electrical connections, and vehicle performance all came to mind and were noted for further analysis.

Since this was a working prototype my first inclination was to test it! Driving the machine gave me a good feeling for how the vehicle should operate as a final product. This was important from a product design perspective since this was the first such drive for me and was a framework for how an electric vehicle should operate. After the test drive the first weeks of the project involved doing my homework, I read technical literature and began to understand how the system as a whole was supposed to function. Also during this time, I organized all project information into a centralized storage repository for easy access.

After I was comfortable with the basic operation of the system it became apparent that the electrical schematic provided was insufficient, and I reproduced a higher detail version on paper. Although the system worked I had some suspicions that it would need to change. The force of this change came from learning, in detail, the operation of the powertrain components; this process revealed multiple improvements in safety features as well as removing unnecessary components of the existing system. Most notably a Programmable Logic Controller (PLC) and Human Machine Interface (HMI) were added to complement the existing systems and expand functionality.

After modification I transposed the diagram into AutoCAD and presented it to the technician on the project, Dennis. As Dennis modified the wiring on the vehicle I refined configuration parameters on the vehicle subsystems such as the electric motor driver and battery management system, I also programmed the HMI and PLC devices. Throughout this phase of the project there was constant communication between Dennis and myself, we were both discovering that the original schematic would not work as planned. We leveraged the nature of the situation to create an interactive and iterative process, where improvements were made while the prototype was built. These changes were immediately tested, documented, and improved upon if necessary.

Another domain where iteration was used extensively was design of the HMI system. I witnessed firsthand the power of iteration during the previous Commander 5 project and was eager to apply it again. The interface and user experience were built in small chunks throughout the project. Each time a new feature was envisioned a prototype was created and tested, usually technicians or other a member of the engineering team would be asked for input on the proposed changes. In the case of the RTV-EV the end result was an interface with four screens, displaying relevant information to users and allowing tests to be performed automatically.

After we were satisfied with the operation of the core computer systems and electronics we moved onto the battery pack. Since this was still a low fidelity prototype the battery box was constructed out of recycled wooden shipping crates. The first step was to physically lay out the batteries in the boxes, after 20 minutes with a measuring tape and calculator I went to work connecting each cell together and to the battery management system. When the battery box was ready Dennis placed the crates onto the vehicle and it was ready to test drive!

Testing was the most insightful phase of the project, since marketing feasibility is based on run time and distance that can be covered by the vehicle on a single charge. The first test that was run was plagued by two loose bolts within the battery pack, causing the vehicle to unexpectedly stop on multiple occasions. After rectifying the issue, a second test was performed which showed promising results.

After testing my work term was coming to an end once again. Throughout the project I kept a detailed notebook, and so my final task was to transcribe all important information into digital format so that others could understand what decisions I had made and which tasks remained to be completed. This vehicle has not yet gone into production since it must first be proved as a viable option in an underground environment, and the second round of testing is currently being scheduled.

Reflections

The most important thing that I learned throughout the project was the importance of task delegation when managing a project. Task delegation was something that I could have improved in this project, I found myself spending lots of time in the shop fixing small issues and not considering bigger picture problems. As such I only had time to run one stage of basic testing and left some important tasks to be completed by the engineering department after my departure.

Another aspect that I could have improved on was constant reassessment of the state and direction of the project. Since I was primarily focused on solving technical problems I did not reassess timelines and tasks to be completed on a regular basis. Lack of focus on where the project was headed on a high level contributed to inefficiencies in work allocation. For example, I did not need to construct the battery box myself, this task could have been allocated to a technician.