> For the complete documentation index, see [llms.txt](https://2025.istvs.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://2025.istvs.org/submissions/papers/7559.md). # 7559 - DYNAMIC CONTACT PATCH ESTIMATION FROM 3D CONTACT PATCH MEASUREMENTS INSIDE A MOVING TYRE UNDER COMBINED SLIP CONDITIONS {% hint style="info" %} Paper presented at ISTVS 2025 | 55th Conference of the International Society for Terrain-Vehicle Systems {% endhint %} **Authors:** *Amal Patel, Schalk Els* **Keywords:** Digital Image Correlation; Tyre Contact Patch; Slip Angle; Pressure Distribution; Dynamic Rolling Radius; Terrain Deformation; Contact Patch Velocity; Intelligent Tyres **Abstract:** Vehicle stability is inherently related to tyre-terrain interaction. Slip conditions arising from tyre forces generated due to the terrain and vehicles state is a valuable indication of a vehicle’s stability. Measurement and analysis of the tyre contact patch is complex, yet abundant information can be derived from contact patch measurements. Literature indicates that analysis of the contact patch is difficult, and indirect methods are used to determine tyre states under ideal conditions of paved roads. Few researchers attempt to directly analyse the contact patch and extract key tyre states: slip angle, pressure distribution, terrain deformation, contact patch velocity and dynamic rolling radius. This study uses the T2Cam apparatus, a mechanism that fits into a tyre and provides the capability to attach cameras inside the wheel that remain stationary despite the tyre rotating. The use of T2Cam and an RGBD camera provides the capability of a non-contact method using DIC (Digital Image Correlation) to measure tyre contact patch deformation and relate that to key tyre states. The purpose of this study is to develop algorithms to extract key states from contact patch deformation of the inside of the tyre carcass under varying tyre conditions. Preliminary findings show tyre deformation of the contact patch is measurable and accurate to be used as an input in an algorithm to calculate slip angle, contact patch velocity and dynamic rolling radius. Overall, determining these factors will enhance the understanding and visualisation of the dynamic contact patch and prediction of vehicle stability on many types of terrain. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://2025.istvs.org/submissions/papers/7559.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.