FreeRTOS is a powerful real time operative system for embedded devices, as they states is ported to 27 platforms, one of them is the LPC17xx, in the Officially Supported Demos they have complex demo projects using CodeRed, Rowley Crossworks, IAR and GCC but they do not have such a project for Keil so this is a *very* basic template project integrating CMSIS, LPCUSB and FreeRTOS.

You can download the template from lpc17xx_project_template_freertos.zip. At this example there are 2 tasks which prints a independent counter on the UART2. You can modify it and put your OS Tasks directly.