On February 20th, the team met to complete the third car build. Here, we were able to finish the novel steering design and finalize the design for the seat frame. The final steering wheel is compressible against two foam blocks to account for limited muscle tone in the arm and bracketed by two U-Brackets to allow for control of steering. The seat frame is coupled to a seat adjuster allowing for forwards and backward motion and a five-point harness is connected directly to the frame to increase safety and adjustability. Below are images of the design schematic and the final products in the car.

An image of a toy car modified to be used by small children with physical and mobile limitations to aid in early cognitive development. This design depicts A)a five-point harness, B)a novel steering and acceleration mechanism and C)a fully adjustable seat frame. All modifications not shown.

From this point moving forward, our team will be aiming to complete the car the week after Spring Break by doing a final car build. Here, we plan to implement the speed controller, insert kickboards with later support foam into the seat frame, and finish the wiring for the button. In addition, we want to move the battery port to the outside of the car so it’s easier to access for the parent. For the seat design, we would ultimately like to implement a mechanism for tilt, although we have not decided on a final design. So far, the leading idea is to have cutouts in the attached kickboard to allow for PVC pipe inserts on either the front end or the back end which would provide tilt and height adjustability. These design ideas can be finalized at the next build.

Our contact from Belmont has informed us that the IRB approval for the Susan Gray School is still in progress and we aim to have the car in the school around the third week of March.

This week for senior design, our group finalized a number of design concepts for our car design. Major additions we plan on adding to our car include a 5-point harness, an adjustable seat, and a forearm tray. These additions will make significant improvement towards increasing the vehicle’s adjustability, support, and safety. The implementation method for these designs have been planned out as well in preparation for an initial build session. An amazon order was placed for initial prototype materials, which should be delivered in time for a planned prototype construction meeting this upcoming Saturday.

A number of materials have been ordered and obtained for the prototype build. This includes PVC piping, a start button, a seat adjuster, the 5-point harness, and a speed controller. The PVC piping will serve as a easily manipulatable material to allow for a wide range of customization for our seat. It is currently planned to remove the current seat within the vehicle, and build a new, adjustable seat out of the PVC piping. A fabric material will be attached to the PVC to allow for a hammock-like seat. The seat adjuster will be placed below the seat, and allow adjustability frontwards and backwards within the car. The current prototype will have the seat adjuster attached with velcro. After confirmation that the front and back adjustability work ideally for the car, more work will be done in the upcoming weeks to allow for adjustability in the vertical direction. The speed controller and start button will serve as functional electric modifications to the car. The addition of the speed controller will allow the caretaker to adjust the maximum speed of the vehicle to a condition deemed safe for the child. Furthermore, the start button will replace the pedal as the mechanism for the child to start the vehicle, allowing children without lower body control to use the car. 

After the work is done this upcoming weekend, more work will be done to continue to refine and develop design ideas. It is believed that hands on construction will allow availability to design and implementation insights likely overlooked within the planning phase. Our group will go over both the failed and successful aspects of our prototype, and make adjustments from there to further optimize our upcoming designs. By the end of the month, our group plans to have a fully completed model that can be used by graduate students at the Susan Gray school to begin testing with children.

Before winter break, our group visited the Belmont School of Occupational Therapy to assist in a car-build in order to better contextualize the current equipment and gain some experience in working with the cars. Our main task was working with a Lightning McQueen model car and attaching a controller to the internal circuitry allowing the user to change the speed settings. From a design perspective, this component is critical for implementation in the school and home settings as the initial speeds of the cars are too fast to be used safely.

In order to implement the device, the seat was removed from the Lightning McQueen car and the battery was detached from the motor. Each lead was cut and stripped and the new component was connected between the devices allowing for multiple settings. By working directly with the car and assembling the different components, we found a clearer understanding of the design constraints and the different aspects we would need to consider.

Our project involves the implementation of “lean tools” and “contextualized adaptations” which are terms describing the simplification of existing technologies and the diversion of existing techniques for new purposes, respectively. In the context of our design, we are optimizing mobility devices that already exist in order to be more cost-effective and readily available as well as repurposing existing technologies, motorized toy-cars, to be used in the clinical setting. With these concepts in mind, our group decided to focus primarily on three main aspects to be determined by clearly defining the needs of the patient and the components we deem important. By comparing these two ideas, we can narrow down the three most important design criteria to focus our efforts and create a quality design.

On Thursday, November 8th, our group visited the Susan Gray School at Vanderbilt to learn more about the patients our mobility devices would be deployed to and understand their needs. Heather Winters, an occupational therapist at the school, was able to take some time to walk us through the school and talk to use about the patient needs. We began by looking at the devices that were already in use, and an old GoBabyGo car to understand why it wasn’t being used.

Major issues with the current GoBabyGo car included that the charger was missing, the user had a difficult time putting a child into the car and that it was bulky and heavy. It was used for a child who exhibited self-injurious behaviour and was only used once in a therapy session.

Next, we went to observe the specific children that our cars would be used by and asked about their particularly limitations and what they would require. We were able to observe two students directly with the following limitations.

• Student 1: 3 year old with fluctuating athetoid cerebral palsy. Specific mobility restrictions includes little muscle tone in arms, and lack of fine motor control, limited communication and lack of fluid movement. Currently uses a Riftch Activity Chair, a weight bearing stander and a gait trainer. Need to address problems with communication, social interactions and muscle control.
• Student 2: 3 year old with spina bifida. Strong upper arm movement and head control with no control below the waist. Limited vision. Currently uses a wheelchair and a stander.

Heather noted that there are two other students that would potentially be able to use our devices but they were not available for us to observe at that time.

On the tour we were also able to see the specific areas that the cars would be used in. Primarily the cars would be used by children on either of two playgrounds at the school. Some important considerations for the playgrounds is that they do include water play areas, have stairs and metal equipment and are not completely covered. The cars would primarily be used on the playground floor and not near the stairs or the metal structure.

Further, some use would be in the gym which included tile floors and blue raised mats. In this area the students would interact with other students and be encouraged to socialize and design considerations should be made for this type of social environment.

Finally, Heather talked to us about some final design aspects that she would want to ideally see. Her suggestions included the following:

• A component of the car that allowed the children to make simple choices to help with communication
• A door that opened
• Secure harnesses
• Increases in resistance as the muscle develops
• Multiple speed levels
• Removable floor for children with some use of their legs
• Removable handle for a parent
• Velcro on pedals if applicable
• A design that is lightweight

During our research, we found a few sources particularly helpful. Our design is largely based on work done previously by the Go Baby Go foundation operated out of the University of Delaware, and there are specific projects on the mobility devices as they relate to Cerebral Palsy, as found below.

• https://sites.udel.edu/gobabygo/
• http://yourcpf.org/cpproduct/go-baby-go-the-ultimate-toy-hack/

Further, on Thursday we were able to visit the Susan Gray school and directly observe the patients that our devices would be helping. Understanding the purpose of the Susan Gray School and its efforts was vital in our research.

• https://peabody.vanderbilt.edu/admin-offices/sgs/index.php
• https://news.vanderbilt.edu/2014/07/10/susan-gray-school/

Finally, understanding the clinical relevance of our project was important to address the cognitive developmental impairments in children. We referenced the literature to characterize these problems and aid in our design development.

• https://www.tandfonline.com/doi/full/10.1080/10400435.2017.1415575
• https://journals.sagepub.com/doi/abs/10.1177/0956797613479974
• https://www.frontiersin.org/articles/10.3389/frobt.2017.00007/full

This week for our design project, we spoke on the phone with one of the pediatric occupational therapists at the Susan Gray School, Heather Winters. On this call, we spoke about some of the current equipment available at the school. Heather went into depth about which pieces of equipment seemed especially useful for the children, as well as what pieces of equipment they felt could potentially be improved. As for the toy cars, there were many design aspects Heather mentioned that she felt would be useful for both the development of individual children and the range of children for each individual car could be used. Talking to an occupational therapist was extremely helpful, since some of Heather’s design insights were ideas that one without her specific knowledge likely wouldn’t come up with. Some of these examples include a 5-point harness and the ability to tilt the car seat at various angles.

In addition to this, we talked to Dr. Teresa Plummer from the Belmont School of Occupational Therapy about next steps moving forward with the Susan Gray School. She solidified the ideas that we came up with after speaking with Heather and mentioned that moving forward in the Susan Gray school may require some extensive protocols for approval. Luckily, Dr. Plummer has a new graduate student starting at the Susan Gray School in January of next year and if we are able to get a prototype working before then we would be able to work alongside her graduate student in studying the development of children with mobility issues. The paperwork would be accounted for and we would be able to test our design in a controlled environment.

Moving forward, we have established a timeline for some key stage gates moving forward. First we will be visiting the Susan Gray School this upcoming Thursday in order to talk to Heather Winters about the needs of the children as well as seem what kinds of design aspects we feel are most important. Working with the children and observing them in the setting which they would use the mobility devices will help us understand all of the needs of the design. We are then meeting as a group at the Wond’ry to be trained and learn about the manufacturing equipment that we have at our disposal. With the manufacturing capabilities in mind, our designs will be more streamlined and cost effective. Next, we will gather all the information from our conference calls, and visit to the Susan Gray school to develop an extremely well defined set of design requirements. We have set a meeting with our advisor to discuss our progress of these milestones, and set out a productive path moving forward.