Real-time motion control on Android platform

Recently, it is increasingly important to provide good real-time performance with the Android platform, since it has been used in industrial devices. The Android platform, however, does not provide a tight real-time guarantee that is required by such industrial devices as robots. Until a real-time extension of the Android platform becomes publicly available, application developers need a lightweight application-centric approach to achieve good real-time performance on the existing platform. This paper proposes an application-centric approach requiring no real-time extensions of the Android platform, which centers around multi-core partitioning and partition-aware application design. Following the proposed approach, we present an implementation study of motion control applications where the real-time tasks of the target application run on dedicated processor cores as a native Linux process while the non-real-time tasks run on other cores as an Android process. In the paper, we prove that the proposed approach is enough effective to deal with motion control applications on the existing Android platform with no real-time extensions. Our experiments show that on a quad-core Android board we can achieve such a good real-time performance as 99 % task activation jitters less than 5 mu s for a motion control application with four real-time tasks and a period of 500 mu s.