3.1 Project Proposal

Introduction

Hand-pulling noodles is a form of art that has been around for a long time but has never been modernized or industrialized. Because of this, hand-pulling remains a technique that is fairly inaccessible to non-professionals, as results can easily be inconsistent and difficult to achieve (ex: Gordon Ramsey having difficulty achieving it in the linked video below). Hand-pulling can also cause health problems that arise from constant repetitive motion. Our goal is to help alleviate some of this strain without changing the art.

Noodle Pulling | Gordon Ramsay

Problem Statement

We aim to create a mechanism that can hand-pull noodles. Currently, no such machine exists — the closest are sugar-pulling machines. We believe that having this mechanism could provide efficiency, accessibility, and consistency, and thereby allow people to enjoy fresh noodles in their homes.

Mechanism

Since hand-pulled noodles are made using a combination of complex motions, we are considering a handful of mechanisms that either solve the full motion or parts of it.

Slider Crank

The first concept is a slider crank mechanism along with a servo motor to create the motion necessary to replicate hand-pulling noodles. We will be splitting up the motion into three parts: an up-and-down motion, a twisting motion, and a forward and backward motion. One of the hooks will stay stationary while the other will perform the pulling movements. The moving hook will utilize a slider crank mechanism to advance forward and backward towards the standing hook, and a servo motor to twist back and forth to grab, twist, and drop the noodles. Between the hooks, there will be a noodle stand that will move up and down to push the noodles into the hooks which will also use a slider crank mechanism.

Accordion

Our second idea for the noodle-pulling mechanism was a system of crossed levers, termed “Lazy Tongs.” This mechanism is shown below in Figure 1. While this mechanism does not imitate the traditional method, it would still achieve something close to the desired effect while being efficient and accessible. This design was researched over others because the horizontal movement also resulted in a change in the vertical height. This is a feature that would help pull the noodles as a concern with mechanizing noodle-pulling is that an inconsistent pull of the dough could result in a tear. For our purposes, there would only be one side moving, with a stationary hook on the other side to hold the noodle in place to be pulled.

Figure 1: “Lazy Tongs” from https://507movements.com/mm_114.html 

Circular to intermittent

Our third proposed mechanism is depicted below in Figure 2. This mechanism has the potential to be the closest to the technique used to pull noodles; however, it will not be able to twist and pull the increasing number of strands of noodles without human assistance. In general, the twisting of the noodles would have to be done with out-of-plane motion. This mechanism stays planar and the intermittent aspect allows for the easy initial pull and the quick pull around. The movement we can get from this mechanism is unique and the path can be manipulated to mimic the human movement.

Figure 2: “Continuous circular motion into an intermittent circular” from https://507movements.com/mm_398.html

Tchebicheff's Four-Bar Linkage

This modified 4-bar mechanism has the intended movement that we saw in a lot of noodle-pulling videos. Mapping out the movement from an instruction video we can see a partially circular and partially horizontal movement, in figure 3 below.

Figure 3. Tracked hand movement from How to Pull Off Thin Hand-Pulled Lamian Noodles | Serious Eats

When mapping the movement of a point on the smallest linkage in a Tchebicheff four-bar mechanism, we can see a very similar shape. This movement can be seen in the video clip below. The main motivation for using this mechanism is its movement being the closest to the traditional method, which is the ultimate goal of the project.

Chebyshev Lambda Linkage

Similar to the previous mechanism, this mechanism was researched due to its movement mimicking the traditional method. The movement of the end of the large linkage makes the shape of a half-circle, the horizontal pulling the noodle and the half-circle bringing the noodles back to the stationary hand. The video attached below shows the movement. 

Proposed Scope

During the semester, our team plans on tackling the noodle-pulling robot by splitting it into three main tasks: pulling, folding the noodles, and preparing the noodles for the next set of pulling. Our aim for the final project is to complete the portion of the noodle-pulling technique that is most difficult to master: the pulling portion. 

Analysis that will be needed before fabrication includes position analysis on how the hook will be moving and how this will lead to the necessary movement to pull the noodles, mimicking the traditional technique. Because we are pulling noodles with the chance that the noodles will rip with too much force, we will need to analyze the motor control for any mechanism to make sure we are not pulling the noodles to rip. Overall, the scope of this project is heavily focused on taking a mechanism and creating more intricate and detail-focused movements that can mimic traditional noodle-pulling while maintaining the integrity of the craft and the noodle.

Preliminary Design

Moving forward, we will be exploring the Chebyshev Lambda Linkage as it seems to appear closest to what we are looking for. The desired position profile is at the end of a link so we will not have to worry about any links needing to cross over the hook/bar attachment which would occur in Tchebicheff's four bar linkage. Additionally, the velocity profile aligns with our desired profile because the speed of the point is similar to the input speed at the lower part which will represent the pulling motion, and the speed is faster at the higher part which will represent the throwing motion. Because the speed is faster at the throwing part, the force on the noodles with be smaller than the input force which is desired as the noodles will be more delicate during the throw part. The noodles need the most force when they are being pulled, which will be approximately equal to the force being input into the mechanism because the speed of the point is very close to the speed of the input linkage. 

Kinematic Diagram

Figure 4. The kinematic diagram on the left and the kinematic diagram with additional design elements to hold the noodles. 

Gruebler's Equation for Calculating Degrees of Freedom of the Mechanism

F = 3(n-1)-2L-H

F = number of degrees of freedom
n = total number of links in the mechanism
L = total number of lower pairs (1 DOF such as pins and sliding joints)
H = total number of higher pairs (2 DOF such as cam and gear joints)

For our proposed design we have:

n = 4

L = 4

H = 0

This gives us 1 degree of freedom. 

Grashof's Law

Figure 5. Relationship between link lengths and the path of the mechanism from https://www.designofmachinery.com/DOM/Chap_03_3ed_p134.pdf

For a Chebyshev Lambda Linkage, the linkage lengths have the following relationship to optimize for a constant velocity (Calculated from https://www.designofmachinery.com/DOM/Chap_03_3ed_p134.pdf)

Link Ratios based on the Maximum delta Vx%

delta X/L2 = 3.456

L3/L2 = 1.863

L1/L2 = 1.575

Our Values:

Delta X = 12in (this value is based on a rough estimate from watching traditional hand-pulling videos)

L1 = 5.47in

L2 = 3.47in

L3 = 6.47in * 2 = 12.94in (the full length)

L4 = 6.47in 

Grashof's 

3.47 + 6.47 < 6.47 + 5.47

Therefore, the shortest link can fully rotate concerning the neighboring link, which we saw in the video, but the law further proves it.

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