Golf Haptic Interface

Project team member(s): Risa Xiang, Anna Yu, Ariel Wang, Harbour Li

Give a one-paragraph description/summary of the project, which includes information like the motivation for the project, the goals of the project, and the resulting implementation and success of the project.

Introduction

For this project, we have chosen a specialized handheld desktop device with 2 revolute joints to match the pivot and the swing of a golf simulator, as well as a vibration motor and virtual environment to give users both kinematic and cutaneous feedback for an interactive gaming experience. This implementation was chosen due to its broad coverage of this course topic, from manipulator kinematics to interactive virtual environments, as well as practicality as a project.

Background

1. Nakamura, T., & Koike, H. (2020). Golf Club-Type Device with Force Feedback for Modifying Club Posture. In CHI EA ’20: Extended Abstracts of the 2020 CHI Conference on Human Factors in Computing Systems. ACM. https://doi.org/10.1145/3334480.3383024

Nakamura and Koike (2020) present a golf club–type haptic training device designed to improve golf swing learning through real-time force feedback. The paper addresses a major limitation in traditional golf training: beginners often rely on verbal coaching, video analysis, or post-swing sensor feedback, all of which provide delayed correction and may reinforce incorrect movement patterns. To solve this issue, the authors propose a handheld device that physically guides the user’s club posture during the swing, enabling immediate motor correction and more efficient motor learning (Nakamura & Koike, 2020, pp. 1–2). The key innovation of the system is its ungrounded force feedback mechanism based on the gyroscopic effect. Unlike grounded robotic training systems that restrict movement, the device generates torque using a spinning mass and controlled rotational actuation, allowing the user to swing naturally while receiving directional haptic guidance. The prototype consists of a golf-club-like grip, gyroscope module, motors, a control board, and a motion capture system integrated with a Unity simulation environment. This setup tracks the club’s position and orientation in real time and applies corrective torque when deviations occur (Nakamura & Koike, 2020, p. 3). To evaluate the device, the authors measured both output torque and system response time. Results showed that the prototype generated sufficient torque to physically influence the user’s wrist and hand posture, with a response time as low as 0.1 seconds, making it suitable for slower golf motions such as putting. Although measured torque was lower than the theoretical prediction due to friction and acceleration limitations, it remained practical for motion guidance (Nakamura & Koike, 2020, pp. 4–5). As a practical demonstration, the authors developed a putting application where corrective torque was applied whenever the club face angle deviated by more than one degree from the ideal trajectory. The study concludes that real-time force feedback can serve as an effective and intuitive training tool for motor skill learning, with strong potential for sports training and rehabilitation (Nakamura & Koike, 2020, pp. 5–6).

2. Basdogan, Cagatay & Srinivasan, Ayam. (2001). Haptic Rendering in Virtual Environments. https://www.researchgate.net/publication/2380464_Haptic_Rendering_in_Virtual_Environments

Computer haptics is the science of developing algorithms that synthesize forces, allowing users to perceive and manipulate virtual objects through a haptic interface. This process, known as haptic rendering, relies on a high-speed haptic loop to ensure system stability and ensure virtual surfaces feel rigid. The core algorithm consists of collision detection to identify contact and collision response to compute the resulting forces and torques conveyed back to the user. Interaction is modeled through several paradigms: point-based, where a single Haptic Interaction Point interacts with objects; ray-based, which models tools as line segments to enable torque; and complex 3D object-object contact between polyhedra. To enhance surface realism, force-shading interpolates surface normals to smooth polygonal edges. Friction and texture are simulated by adjusting reaction force vectors based on local gradients. Texturing techniques include image-based methods using 2D height data and procedural methods using mathematical functions like fractals or noise. For more complex environments, deformable objects are rendered using geometry-based techniques, such as vertex or spline manipulation, or physics-based models like particle systems and the Finite Element Method. Modeling dynamic objects requires solving rigid body motion equations in real-time to update positions and rotations. Beyond individual interactions, advanced capabilities include recording and playing back haptic stimuli for training and neuro-rehabilitation, as well as shared haptics, which enables networked users to collaborate in a single virtual space. Future advancements aim to integrate tactile displays that simulate direct skin contact and temperature patterns, alongside improvements in hardware resolution and specialized processing.

3. A. Tekriwal and S. Sharma, "GolfGuide : Smart Golf System with Haptic Feedback and Auditory Cues for Visually Impaired Individuals," 2025 7th International Conference on Intelligent Sustainable Systems (ICISS), India, 2025, pp. 907-916, doi: 10.1109/ICISS63372.2025.11076425. Smart Golf System with Haptic Feedback and Auditory Cues for Visually Impaired Individuals

GolfGuide is an innovative assistive technology designed to make golf more inclusive for visually impaired individuals by addressing fundamental challenges such as ball location and swing mechanics. The system's hardware includes a golf club integrated with an MPU6050 Inertial Measurement Unit (IMU) to track 3-axis motion, five Force Sensitive Resistors (FSRs) to monitor grip pressure, and a Hall Effect sensor that works with a magnet on the tee to detect ball proximity. Data is processed by an ESP32 microcontroller and transmitted wirelessly to a computer, where Long Short-Term Memory (LSTM) networks analyze temporal patterns to evaluate performance. Users receive multimodal feedback through haptic vibrations for mechanical corrections and auditory cues from a piezoelectric buzzer that increases in volume as the club head nears the ball. Experimental results demonstrate high efficacy, with the system achieving 93% accuracy for grip strength prediction and 86% for swing evaluation. Future research aims to refine these models by incorporating diverse environmental variables like wind and terrain, while also exploring advanced feedback methods such as AI-based voice coaching to further enhance user independence.

Methods

Provide a detailed description of your project, such that another student from the class could generally re-create your project/experiment from the report if necessary. (You don't need to document every screw, but the design should be clear.) Add images and videos as needed to support the description. You can refer to downloadable drawings and code in the "Files" section (later). You should divide this section into subsections, which can vary depending on your particular project. Here is an example set of subsections:

Hardware Design and Implementation

System Analysis and Control

Demonstration / Application

Results

Describe the results, which may include qualitative responses from users at the open house.

Future Work

Describe how your system could be tested (e.g., through experiments if you have not already done so), how it can be improved, and how it might be applied.

Acknowledgments

Here you can list any individuals or groups who helped you with your project. (e.g., another student in the class, a course assistant, or an especially helpful PRL TA). Optional, so delete this section if you aren't using it.

Files

Code and drawings should be linked here. You should be able to upload these using the Attach command. If you aren't willing to share these data on a public site, please discuss with the instructor. Also, in this section include a link to a file with a list of major components and their approximate costs.

References

List the referenced literature, websites, etc. here.

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Appendix: Project Checkpoints

Checkpoint 1

• Goal:

By this checkpoint, we aim to have the mechanical prototype about 80% completed through 3D printing, with the motor and required sensors selected. The design requirements and specifications should be finalized, including defining the intended gameplay objectives and the user experience we want to create (e.g., target sensations and interactions). The mechanical and electrical systems should be integrated and ready for initial code testing. On the software side, the game should have a functional basic version completed, including core game logic and essential in-game objects.

• Team Progress Update:

Figure #: Initial concept drawing

At this checkpoint, the project has made solid progress toward the planned goals, although several integration tasks are still in progress.

From the mechanical perspective, the device design is approximately 80% completed in CAD. The overall assembly architecture has been defined, including the three major mechanical subsystems:

• Base + chassis + Motor 1 + Capstan Drive 1
• Tower assembly + Motor 2 + Capstan Drive 2
• User handle + golf club + vibration motors + linkage mechanism

Currently, the base section of the device has been 3D printed and used for initial fit and structural evaluation. However, the complete mechanical assembly has not yet been fully fabricated or assembled through 3D printing.

On the hardware side, all major actuation and sensing components have been selected, including the DC motors, optical encoders, and vibration motors. The team has also continued refining the mechanical linkage and interaction design to support the intended golfing motion and haptic feedback experience.

From the software perspective, a basic graphics environment has been generated, and the initial code structure and signal mapping framework have been developed. These include preliminary templates for integrating device motion and gameplay interaction. However, the software modules and mappings have not yet undergone full team review or integrated testing.

Overall, the project has established the core mechanical architecture, selected the required hardware components, and initiated both software and system integration development. The next phase will focus on completing full mechanical fabrication and assembly, integrating the electrical and mechanical systems, validating sensor and motor functionality, and refining the gameplay and haptic interaction experience through testing and iteration.

https://docs.google.com/spreadsheets/d/1z032SW_FavX9c2kPuF-KOvd41SU4SF96tfZlnoqKBLc/edit?usp=sharing

Base + Chassis:

Figure #: Base and chassis CAD along with the Hapkit board, motor, and encoder Attach: Printed BaseChassis.png Δ Figure #: First iteration of the base and chassis printed and assembled

Tower + Sector Wheel:

Linkage mechanism:

Checkpoint 2

Here you will write a few paragraphs about what you accomplished in the project so far. Include the checkpoint goals and describe which goals were met (and how), which were not (what were the challenges?), and any change of plans for the project based on what you learned. Include images and/or drawings where appropriate.

Example Video: https://www.youtube.com/watch?v=i_aLBql4Ufo