Smartphone-based Mobile Robot Remote Control System

The development of Network-based Robot has been greatly promoted from thetraditional military and industrial applications to telemedicine, education,entertainment, services, and other fields. This is benefit from the development ofInternet, which is inexpensive, flexible, and easy expansion. However, due to thelimited network bandwidth, randomly varying network load and networktransmission mechanisms, there are random network latency and packet lossproblems, which lead to poor performance of NCS (Network Control System), eveninstability.A number of methods have been developed to compensate the random networkdelay, such as delay shaping method, event control method, stochastic controlmethod and the predictive control law. For event control method, the description ofthe system is changed from the traditional time parametric to event, which ensuresthe stability and security, but has low efficiency. The other methods model thenetwork delay in different forms respectively. For delay shaping method, randomdelay is modeled into fixed delay, which is conservative. For stochastic controlmethod, the premise is to know the probability characteristics of the network delay.However, this is more difficult for the complex Internet network latency. Predictivecontrol method has achieved good results in network delay compensation, and thepresent study is relatively mature.The subject is focused on network delay compensation, and thereby to ensurethe stability, timeliness and accuracy of the system. In order to realize network delaycompensation, network predictive control method based on model-based predictivecontrol law is adopted. Sets of remote trajectory tracking experiments in differentnetwork environments have been conducted with mobile robot and smart phone. Theexperimental results show that network predictive compensation algorithm caneffectively compensates for network delay, and ensures good performance of thesystem. Delay compensation is necessary in non-LAN environment. At the sametime, tracking experiments with different trajectories have been designed. Theexperimental results show that the compensation algorithm can reduce the speedlimit of the mobile robot. In fact, the faster the robot runs, the more significanteffect of the delay has. Therefore, the algorithm has great significance on improvingthe efficiency of the robot control system.In addition, an innovation of the subject is the use of smart phone as the robotremote control terminal, which is portable. In fact, with the development oftechnology, the performance of smartphones is more powerful. In addition to traditional communication functions, it also has video processing, wifi, touch screen,speech recognition and other rich features. Besides, the processor speeds of thecurrent smart phone is up to1GHz or more basically, which enables most of theapplications running on the computer can also run smoothly on the phone.Therefore， the usage of smart phone as a remote monitoring device has practicalfeasibility, and it breaks the dedicated-bulky defects of traditional robot controller.