An assistive robotic arm for helping feed people with physical disabilities of the extremities is presented in this paper. In order to detect foods on a plate, HOG based food detectors were created and implemented in our robotic arm system. The system consists of a 6-axis robotic arm, Web camera, laptop computer, and microcontroller. Using the robotic arm system, we performed two experiments: (1) eating chicken nuggets task and (2) eating shao mais task. It was found from the experimental results that the proposed assistive robotic arm system could stably transfer chicken nuggets and shao mais to the user's mouth.