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Group 2: Adapted Tricycle/Stroller


The goal of this project is to design and create a mobility device that will help strengthen certain aspects of a young toddler with motor skill problems.

Team Members (clockwise) Tomas Attalla Jacob Burian Jonathan Seals John Michael Rampy

Problem Statement

The infant is currently around one year old and has a difficulty with his back and sitting up on his own. The immediate goal is to create a stroller or walker that will provide a high level of comfortability but will also provide assistance with strengthening his back for sitting up on his own. In terms of a long term goal, the family would also like for the stroller to convert into a device that can be powered and steered by the child when he is of age. Lastly, the family would like a fun design that the child would enjoy as he grows up.

Design Specifications

  • Comfortable straps positioned to help train the infant to sit up
  • Foot rest for the child
  • Storage for the parent
  • Converts into a tricycle
  • Side bars to ensure safety

Background Research

When looking for tech for design ideas we found a tricycle stroller that had some innovative ideas that could be incorporated into our final design. There were other examples that had long adjustable straps so as the infant grew, the device would still be able to hold him comfortably.

Concept Design 1

Concept one was the most practical of the three. It met all the criteria the family was asking for in terms of a stroller that would convert into a tricycle.

Concept Design 2

Concept two was designed to meet the needs of the family for a stroller with a fun design for the child.

Concept Design 3

The final concept was a simple design that would meet the needs of a stroller and do all the functions the family had requested.

Selected Concept Design

For our selected design, we decided to go with design 1. We chose a three-wheel based system for the functionality it would have as a stroller, but also for its ability to change into a tricycle when the infant is of age. The handle for the adult operating the stroller will have full control over the speed and direction. The design for this gives the infant comfortability while it is in the stroller stage, and will also give him that same safety and luxury when he uses it as a tricycle.
After collecting the information about each part needed for this design and creating our bill of materials, the total for fabricating our design would be expensive with buying each part individually. The solution for this was to buy a stroller/tricycle and make additional adjustments to improve upon the safety. The additional component for this tricycle were shoulder rests on the sides that would control the child’s movements in all directions and not just forwards and backwards.

Overview of Selected Design

One of the key details in the design include the removable pedals. The inside cylinders of the foot pedals will be threaded and can be screwed in and transferred from footrest to front wheel for the tricycle. Another detail is the steering mechanism for the adult’s control. It is a swivel system that will be implemented inside of the base. The handle that is connected to the shaft will turn the beginning of the two-bar system causing the front wheel to turn with the movement. One last detail is for the handlebar shaft for the adult. If transportation is needed for the stroller, the handlebar can be pushed down in the same way that crutches can change in length.

  • The design must be stable and secured. While the adult is in control, they should have no worries of a possible malfunction in the straps and the position of the infant.
  • The stroller must help with gaining strength and creating muscles for sitting up independently.
  • Comfortability. The child must be able to have some room to move but the stroller’s purpose is still to help with muscle growth.
  • Weight of the tricycle. Once the child is of age, the machine should be light enough that he is able to pedal himself.

Engineering Analysis 1

For the first analysis we simulated a load of the infant’s foot and leg on one of the pedals. We looked up the percentage mass of a foot and a leg and used the weight of a 1-year-old for this weight force. Simulink, with certain constraints, was able to produce these results with the factor of safety being 15.

Engineering Analysis 2

For the second analysis we simulated a load of the parents’ handle on one of the push bars of the stroller. We decided to use a force of 30 pounds split between two handles. This is because we assumed the kid weighs about 30 lbs. Simulink, with certain constraints, was able to produce these results with the factor of safety being 15.

Engineering Analysis 3

For the third analysis we simulated a load of the child on the stroller. We decided to use a force of 30 pounds. This is because we looked average weight of a 2 year old and it was around 30 lbs. Simulink, with certain constraints, was able to produce these results with the factor of safety being 15.

Bill of Materials

Document Fabrication Process

To begin adjustments of the new stroller we had to begin with a 3-D printer. We designed an enclosure for the child to improve the safety of the stroller and reduce swaying from side to side of the child. The shoulder rest would fit on each side of the seat firmly and were connected by straps. To attach the two shoulder rests together, the straps had to be hand sewed to each other so they could go around the entire seat and lock in together.

Testing Results

To ensure safety, the stroller was brought to Dr. Canfield and forces were applied to the shoulder rests to ensure that they were firm and would not move and break during use.

Completed Design Photos


2021 Spring