8.1 Project Proposal
Introduction
Our team is proposing a mechanism that will capture the complex motion required from a person bowling a ball to score a strike. Though it seems unnecessary at first, any person who has been bowling most likely knows the satisfying feeling of a strike. We want to capture this feeling through our mechanism with a perpetual visual demonstration of this motion being achieved and, as a result, the ball successfully gliding through all 10 pins. This mechanism will require us to consider using position, velocity, and force analysis as it is necessary in assuring the ball glides and spins properly over the surface in order to achieve that strike.
Problem Statement
When trying to recreate the position, velocity, and force profiles of a human bowling, the problem becomes significantly more complex than a simple bowling mechanism. The position of the ball starts close to the chest and gets further out as you release the ball and at the release some sort of spin on the ball has to be incorporated. The velocity of the ball increases as you get closer to releasing the ball. The force of the ball must also reach a certain sweet spot to knock down all the pins. A simple joint mechanism lacks the capability of varying these factors together and isn’t capable of adding spin on the ball at the release as well without a multi-link mechanism capable of nonlinear motion.
Mechanism
Our proposed mechanism consists of four links, with one link grounded. Two links extend from this grounded link, one acting as a coupler and another one acting as a crank, both This mechanism would consist of a grounded frame, a rotating input link (crank), a coupler link that follows a controlled path, and an output link that holds/interacts with the bowling ball.
The mechanism would function by converting rotary motion from a motor or manual input into a smooth, repeatable throwing motion. By adjusting link lengths and pivot positions, the launch angle, velocity, and force can be fine-tuned for optimal performance. Additionally, a spring-loaded or cam-assisted release mechanism could help ensure a consistent and accurate ball delivery, mimicking the controlled arm swing of a bowler.
Proposed Scope
This project aims to create a bowling arm that generates a realistic amount of spin and force to accurately bowl a marble. During the semester, the focus will be on:
Design and Simulation: First designing and assembling the mechanism in MotionGen until getting the desired path of motion. Next, creating a CAD model of the mechanism and performing position and velocity analysis.
Prototype Development: Constructing a functional prototype using 3D printed and/or laser-cut parts. Adding an actuator to the mechanism to consistently replicate the motion. Considering creating an attachment to hold the marble that provides spin out-of-plane. This will include an additional link attached to the slider that twists the marble as it releases.
Testing and Evaluation: Measuring launch consistency and fine-tuning force application. If necessary constructing new parts to improve the launching consistency and flow of motion.
Final Demonstration: Showcasing the completed mechanism with fairly accurate and repeatable launches.
Preliminary Design
Kinematic Diagram
Position Analysis
Potential formulas needed:
Velocity Analysis
Potential formulas needed: