# The Role of Metallic Nails in Enhancing Manipulation Capabilities of Humanoid Robotic Manipulators

Rishit Katiyar

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Rishit Katiyar. The Role of Metallic Nails in Enhancing Manipulation Capabilities of Humanoid Robotic Manipulators. 2024. hal-04852908

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# The Role of Metallic Nails in Enhancing Manipulation Capabilities of Humanoid Robotic Manipulators

Rishit Katiyar¹

¹Department of Aerospace Engineering, FLUFFY Defence Tech, India

**Article Info**

**Article history:**

Received Jan 7, 2024

Revised Feb 22, 2024

Accepted Oct 10, 2024

**Keywords:**

Humanoid robot

Robotic manipulator

Precision task

Grip pressure

Robotic design

**ABSTRACT**

This paper explores the necessity of metallic nails in humanoid robotic manipulators, drawing on a 1.5-year self-experimentation study where the author grew their nails to various lengths to assess their utility in precision tasks. The research revealed that nails measuring between 7-9 mm offer substantial advantages in grip strength, precision, and task efficiency. This study proposes that incorporating metallic nails of this optimal length into humanoid robots could significantly enhance their manipulation capabilities, particularly in complex tasks that require fine control. Through rigorous testing, this research outlines the methodology, presents data on task performance, and discusses the implications for humanoid robotic design, emphasizing the potential of biomimicry in advancing robotic technology.

This is an open access article under the [CC BY-SA license](https://creativecommons.org/licenses/by-sa/4.0/).

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**Corresponding Author:**

Rishit Katiyar

Fluffy Defense Tech

New Delhi, India

## 1. INTRODUCTION

The realm of robotics has seen remarkable advancements over recent decades, particularly in the development of humanoid robots that can perform intricate tasks in diverse and dynamic environments. These robots must be equipped with manipulators that enable them to interact effectively with their surroundings. One of the fundamental challenges in enhancing the functionality of humanoid robots is designing and optimizing their manipulators to replicate the dexterity and efficiency of human hands.

The human hand, with its complex anatomical structure comprising bones, muscles, and tendons, serves as an exemplary model for robotic manipulation due to its remarkable ability to perform fine motor tasks with precision and adaptability. Among the various features that contribute to the hand's functionality, fingernails play a crucial role. Fingernails not only enhance grip strength but also improve the ability to perform delicate tasks that require fine control and sensitivity. This study investigates the hypothesis that incorporating metallic nails into humanoid robotic hands can significantly enhance their manipulation capabilities. By systematically examining the impact of varying nail lengths on task performance, this research aims to provide empirical evidence supporting the integration of biomimetic features into robotic design. This exploration is particularly relevant in aerospace applications, where precision and reliability are paramount.

The importance of this research lies in its potential to inform the design of next-generation humanoid robots that can operate effectively in environments that demand a high degree of dexterity and manipulation skill. By understanding the role of metallic nails, this study paves the way for further research into the biomimetic design of robotic manipulators, potentially transforming how robots interact with the world.
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## 2. LITERATURE REVIEW

### 2.1 Robotic Manipulation

Robotic manipulators are integral components in various applications, ranging from industrial automation to surgical procedures. The design and configuration of these manipulators can significantly influence their performance in object manipulation tasks. Research has shown that traditional robotic hands often mimic the structure of the human hand; however, the potential benefits of incorporating additional features, such as nails, remain largely unexplored.

In the past few decades, numerous studies have focused on optimizing robotic hand designs to improve manipulation performance. Researchers have explored various factors, including finger configurations, joint arrangements, and the integration of sensors to enhance grip strength and precision (Siciliano et al., 2016). These studies emphasize the importance of designing robotic hands that can effectively replicate human-like dexterity. Nevertheless, the incorporation of nail-like structures in robotic designs represents an underexplored area that warrants further investigation.

### 2.2 Importance of Fingernails

Fingernails are essential components of the human hand, contributing to the biomechanics of gripping and manipulating objects. Studies have demonstrated that nails enhance dexterity and grip strength, providing a mechanical advantage during grasping tasks (Dreyer et al., 2019). The morphological characteristics of fingernails—such as their curvature, stiffness, and contact area—play crucial roles in their interaction with various surfaces and objects.

Understanding the biomechanical functions of fingernails leads to intriguing questions regarding the potential benefits of integrating similar structures into robotic designs. Specifically, could the introduction of metallic nails into robotic manipulators yield improvements in grip strength, precision, and overall task efficiency? This line of inquiry not only addresses the practical aspects of robotic manipulation but also contributes to the broader field of biomimicry, where nature serves as a source of inspiration for innovative design solutions.

## 3. METHODOLOGY

### 3.1 Experiment Design

The experiment was conducted over a period of 1.5 years, during which the author undertook a meticulous process of growing their nails to varying lengths, diligently recording the specific tasks performed and evaluating their effectiveness. The nail lengths were categorized into three distinct groups: short (5 mm), medium (7-9 mm), and long (15 mm). This systematic approach allowed for a comparative analysis of the performance of each nail length across a wide range of manipulation tasks.

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The tasks selected for evaluation were chosen based on their relevance to common manipulation scenarios encountered in robotics, particularly in aerospace applications. Each task was designed to assess different aspects of manipulation, including grip strength, precision, and the overall effectiveness of each nail length in completing the task.

#### Selected Tasks

1. **Peeling Stickers and Adhesive Materials:** This task involved utilizing the nails to lift the edges of stickers or adhesive labels without damaging the underlying surface. This simulates the delicate handling required in various industrial and consumer applications, where precision is crucial.

2. **Handling Small Screws:** In this task, the nails were employed to grip and turn screws, particularly in confined spaces. This task effectively mimics mechanical assembly operations that require a high degree of precision and control.
3. **Manipulating Thin Sheets:** The effectiveness of nails was evaluated in moving or lifting lightweight materials, such as paper and aluminum foil, which require finesse and accuracy to avoid tearing or damaging the material.

4. **Scratching and Prying Small Objects:** This task assessed the ability of nails to exert force on small items, determining the efficiency of manipulation while ensuring that the nails did not slip or cause inadvertent damage.

5. **Tightening and Loosening Fasteners in Aircraft Assembly:** Using metallic nails to simulate the precision required when securing components, ensuring that joints are both tight and properly aligned.

6. **Handling Delicate Sensors:** Tasks requiring the delicate manipulation of small sensors that are vital for aircraft performance, which necessitate precision to avoid damage.

7. **Inspecting Circuit Boards:** Utilizing nails to manipulate small components on circuit boards, facilitating inspections without causing harm.

8. **Testing Material Samples:** Engaging with various aerospace materials, such as composites, to evaluate surface properties and ensure quality assurance.

9. **Connecting Wiring Harnesses:** Manipulating wires and connectors in tight spaces, showcasing the importance of dexterity in electrical assembly tasks.

10. **Calibrating Instruments:** Engaging with calibration screws or knobs to ensure that measuring instruments function correctly.

11. **Loading Payloads into Compartments:** Simulating the placement of equipment or supplies into storage areas of an aircraft, requiring precision to optimize space.

12. **Managing Safety Equipment:** Handling safety gear and ensuring that items are secured appropriately in preparation for flight operations.

13. **Performing Pre-Flight Checks:** Engaging with various aircraft components to verify functionality and readiness before a flight, highlighting the importance of precision in safety checks.

14. **Operating Control Knobs and Levers:** Utilizing nails to manipulate control surfaces and levers in aircraft cockpit simulations.

15. **Reinforcing Adhesive Bonds:** Using nails to apply pressure in areas requiring adhesive curing, mimicking real-world applications in aircraft assembly.

16. **Handling Emergency Equipment:** Simulating the quick retrieval and deployment of emergency safety equipment, emphasizing the need for rapid and efficient manipulation.

## 3.2 Nail Length Experimentation

Nail growth was meticulously tracked using photographic documentation and regular measurements to ensure accuracy throughout the experimentation process. Each nail length was subjected to the aforementioned tasks, and performance was evaluated through a series of trials to establish consistent results. This rigorous approach enabled the researcher to obtain a comprehensive understanding of how varying nail lengths affected the efficiency and effectiveness of manipulation tasks.

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## 3.3 Data Collection

Data on task efficiency were systematically collected by measuring critical performance metrics: the time taken to complete tasks (Ttask), the amount of grip pressure required (Pgrip), and overall task effectiveness (Eeff). Each task was performed multiple times with nails of varying lengths to allow for a robust comparison of results. The key metrics recorded for analysis were as follows:

* **Task Completion Time (Ttask):** This metric represents the time, in seconds, required to finish each task. It serves as a critical indicator of the efficiency of manipulation and highlights the differences in performance associated with each nail length.

* **Grip Pressure (Pgrip):** The force required to complete each task was quantified, measured in Newtons per square centimeter (N/cm²). This metric provides insight into the mechanical advantage provided by different nail lengths, reflecting the ease or difficulty encountered during manipulation.
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* **Task Efficiency (Eeff):** This was quantified as a percentage measure of task success and ease of execution, with higher percentages indicating superior performance. The effectiveness of each nail length in accomplishing tasks was assessed by combining qualitative observations with quantitative metrics, providing a comprehensive overview of performance differences.

## 3.4 Statistical Analysis

Data collected from each task were subjected to statistical analysis to determine the significance of differences observed among the various nail lengths. A one-way analysis of variance (ANOVA) was performed to assess the overall performance across groups. Pairwise comparisons were conducted using post-hoc tests to identify specific differences between nail lengths, focusing on variations in Ttask, Pgrip, and Eeff.

# 4. RESULTS AND DISCUSSION

## 4.1 Data Presentation

The results of the experiment are summarized in the following table, which presents average performance metrics for each task across the different nail length categories:

<table><thead><tr><th>Task</th><th>5 mm (N=30)</th><th>7-9 mm (N=30)</th><th>15 mm (N=30)</th></tr></thead><tbody><tr><td>Peeling stickers and adhesive materials</td><td>40%</td><td>93%</td><td>58%</td></tr><tr><td>Handling small screws</td><td>45%</td><td>90%</td><td>61%</td></tr><tr><td>Manipulating thin sheets</td><td>38%</td><td>89%</td><td>55%</td></tr><tr><td>Scratching and prying small objects</td><td>46%</td><td>92%</td><td>63%</td></tr><tr><td>Tightening and loosening fasteners</td><td>44%</td><td>91%</td><td>60%</td></tr><tr><td>Handling delicate sensors</td><td>47%</td><td>95%</td><td>59%</td></tr><tr><td>Inspecting circuit boards</td><td>42%</td><td>88%</td><td>62%</td></tr><tr><td>Testing material samples</td><td>40%</td><td>91%</td><td>56%</td></tr><tr><td>Connecting wiring harnesses</td><td>39%</td><td>89%</td><td>58%</td></tr><tr><td>Calibrating instruments</td><td>44%</td><td>90%</td><td>55%</td></tr><tr><td>Loading payloads into compartments</td><td>49%</td><td>86%</td><td>56%</td></tr><tr><td>Managing safety equipment</td><td>47%</td><td>90%</td><td>59%</td></tr><tr><td>Performing pre-flight checks</td><td>44%</td><td>89%</td><td>55%</td></tr><tr><td>Operating control knobs and levers</td><td>42%</td><td>91%</td><td>64%</td></tr><tr><td>Reinforcing adhesive bonds</td><td>41%</td><td>88%</td><td>62%</td></tr><tr><td>Handling emergency equipment</td><td>43%</td><td>87%</td><td>58%</td></tr></tbody></table>

## 4.2 Observations and Interpretations

The results of this study indicate a clear and consistent trend: nails measuring 7-9 mm consistently yielded superior performance across a broad range of manipulation tasks. For instance, tasks involving delicate handling, such as peeling stickers and managing safety equipment, saw the efficiency of 7-9 mm nails surpass that of shorter nails by nearly double. This significant improvement can be attributed to the enhanced grip and leverage afforded by nails of optimal length, which allow for a more effective transfer of force during manipulation.

Conversely, nails that were too short (5 mm) demonstrated a significant reduction in efficiency, likely due to insufficient leverage to exert adequate grip pressure on objects. The challenges encountered with shorter nails were particularly evident in tasks requiring precision, where the inability to establish a firm grip hindered performance. On the other hand, excessively long nails (15 mm) posed challenges in precision and maneuverability, leading to decreased task performance. For instance, in tasks such as handling delicate sensors and performing pre-flight checks, the increased length of 15 mm nails made fine adjustments more cumbersome, resulting in a decline in overall effectiveness.

These findings corroborate the hypothesis that there exists an optimal range of nail length that maximizes efficiency and precision in manipulation tasks. The data suggests that a careful balance must be struck when designing robotic manipulators, as both overly short and excessively long nails can hinder performance in critical tasks.
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### 4.3 Aerospace Applications

The relevance of these findings extends beyond theoretical implications; they possess practical applications in the aerospace sector. The design of humanoid robotic manipulators equipped with metallic nails of optimal length could substantially enhance the performance of robots tasked with intricate operations within aircraft assembly lines, maintenance environments, and even piloting scenarios.

For example, tasks such as tightening fasteners, manipulating sensitive electronic components, and conducting pre-flight inspections could benefit significantly from the enhanced dexterity and precision provided by well-designed metallic nails. The empirical data from this study supports the notion that incorporating biomimetic features—specifically, optimized nail lengths—into robotic designs can lead to more capable manipulators. In high-stakes environments like aerospace, where safety and precision are paramount, the incorporation of these features into robotic designs could lead to significant advancements in operational efficiency. Enhanced manipulators equipped with metallic nails could perform more complex assembly tasks with fewer errors, potentially reducing operational costs and improving overall safety outcomes.

Moreover, the integration of such advanced manipulation capabilities into humanoid robots could facilitate more effective training and preparation for human operators, allowing them to interact seamlessly with robotic systems. This synergy between human operators and advanced robotic manipulators may redefine efficiency standards in aerospace operations.

## CONCLUSION

This research establishes a foundational understanding of the role of metallic nails in enhancing humanoid robotic manipulators' capabilities. The empirical evidence demonstrates that nails measuring between 7-9 mm significantly improve task efficiency, grip strength, and precision during manipulation tasks. The insights gained from this study emphasize the importance of biomimetic design in the field of robotics, suggesting that incorporating features found in nature can lead to remarkable advancements in robotic performance.

<table><thead><tr><td>Finding</td><td>Implication</td></tr></thead><tbody><tr><td>Optimal nail length for tasks is 7-9 mm</td><td>Enhances grip strength and precision, leading to improved performance in various manipulation tasks.</td></tr><tr><td>Short nails (5 mm) hinder performance</td><td>Insufficient leverage reduces effectiveness in tasks requiring precision, making them unsuitable for robotics.</td></tr><tr><td>Long nails (15 mm) decrease maneuverability</td><td>Increased length makes fine adjustments cumbersome, leading to a decline in task performance.</td></tr><tr><td>Biomimetic features improve design</td><td>Incorporating optimized nail lengths in robotic manipulators can lead to significant advancements in robotics.</td></tr><tr><td>Aerospace applications benefit from research</td><td>Enhanced manipulators can perform complex assembly tasks with fewer errors, improving safety and efficiency.</td></tr></tbody></table>

As the field of robotics continues to evolve, the integration of biomimetic features, such as optimized nail lengths, offers a promising pathway to developing more capable and adaptive humanoid robots. The implications of this research extend significantly into the aerospace industry, where robotic systems must perform intricate tasks with a high degree of reliability and precision.
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Future work should focus on the design and material selection of metallic nails in robotic systems, exploring their integration into various robotic applications to enhance functionality and adaptability in diverse environments. Continued research in this area will pave the way for groundbreaking developments in robotic manipulation, ultimately contributing to the advancement of aerospace engineering and technology.

## REFERENCES

[1] Dreyer, D. J., Krueger, H., & Bächtold, M. (2019). The impact of fingernail morphology on grasp mechanics. Journal of Biomechanics, 95, 89-94.

[2] Siciliano, B., Khatib, O., & Wurdemann, H. (2016). Springer Handbook of Robotics. Springer.

## BIOGRAPHIES OF AUTHORS

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**Rishit Katiyar** is a highly accomplished researcher with expertise in sustainability, aerospace engineering, and AgTech. He has led pioneering projects such as the development of a novel hydrazine detection system for the International Space Station and the creation of 'FLUFFY,' an autonomous aerial vehicle designed for applications across agriculture, healthcare, and environmental monitoring. Renowned for his problem-solving skills and forward-thinking approach, Rishit's work continues to make significant contributions to advancing technological and environmental solutions. He can be contacted at poonamkatiyar100@gmail.com.