Exercise Equipment Design and Manufacture Project

For this project, I worked with a team of 4 to research, develop and partially manufacture a new exercising equipment with the important requirement being that the user had to perform a cranking motion in order to exercise. We went through a typical product development and design process with these phases: MRD, PRD, Project Planning, Conceptualization, Concept Level CAD Design, Engineering Simulation, Material Choices, Detailed CAD Design with Engineering Drawings, BOM, Building the Functional Prototype, and Testing.

MRD, PRD, Project Planning

We first performed market research on the exercising industry and existing products that involves cranking and their general pricing. We also interviewed 33 individuals with 27 being possible consumers and 6 sport medicine and human physiology experts on what they believe are lacking in current exercising products and how cranking may be beneficial to the human body. Through the data we gathered from this process, we decided that our target user should be people of all gym levels looking to combine strength training surrounding the larger shoulder muscles with cardiovascular workouts and our target customer will be gym owners.

For the PRD, we wrote a definitive document that clearly illustrates the necessary constraints that the product needs to follow in areas such as safety, functionality, reliability, accuracy and precision, maintenance and repair, cost target, compliance, packaging and distribution and so on, with clear references made to each of our assumptions.

With these documents done, we moved on to project planning where I set up a Gantt chart and a planning document with clear milestones, metrics, constraints and individual tasks listed and updated on a weekly basis.

Conceptualization, Concept Level CAD Design, Engineering Simulation, Material Choices

We brainstormed and sketched out numerous methods of exercising with cranking involved and also different ways to provide resistance to the cranking motion such as friction, magnetism, water resistance, etc. After weighing our options carefully using tools such as Pugh charts, we decided to move forward with a Sheffield handcar cranking mechanism with pneumatic air resistance. To simply explain the system, the user first kneels on a pneumatic cylinder connected surface, and when they exert force on the handle bar moving each side up and down, the motion turns a wheel which in turn drives a smaller pneumatic cylinder to compress and pump pressurized air to the bigger cylinder underneath the kneeling pad that elevates the user though a vertical path. The weight of the user serves to be the resistance needed to crank the handlebar since the user needs to use force to compress the air enough to reach the pressure needed to raise themselves. 

Finalizing on our idea generation, we used Solidworks to CAD the conceptual design of the entire equipment, ran simulations and calculations to make sure our system is viable to the average user and help us make decisions on what materials to purchase that can support the weight of the product and the user with a safety factor of 1.5.

Detailed CAD Design with Engineering Drawings, BOM, Building the Functional Prototype, Testing

After our design concept was approved, we moved on to the next stage of preparing to build the resistance mechanism. We weren't required to build the entire product due to time and monetary constraints. First, we 3D modeled and produced engineering drawings for all the parts that weren't OTS. We machined the metal components with processes such as drilling, milling, welding, cutting, and also 3D printed a lot of components that were difficult to manufacture. We assembled all the parts, wrapped it with vinyl for a cleaner, sleeker look and I also added on a logo which really brought the aesthetics of the product together. We kept track of all the parts and costs though a BOM and was able to stay under our cost target even including labor, shipping, warranty and other costs. 

After finishing the prototype, we tested our device with a range of different weights and found that the device does require a similar level of force and cycles, which is correlated with the user's weight, as calculated to operate.

Overall, I learned a lot through this project and gained experience in most areas of the product development cycle, especially in documentation and rapid prototyping.