Research On Controllability And Motion Planning Of Modular Self-reconfigurable Robots

Modular self-reconfigurable robots is connected robot systems which consist of aseries of functional autonomous modules with same structure but independent of eachother, and the modules have certain sensing, computation, movement, autonomousconnection and separation ability. The robots can autonomously change their logic orphysical structures to implement a certain degree of functional tasks by sensing theenvironment and their own state according to the target requirements. Such robots areprovided with robustness, versatility and adaptability and suitable to work properly inunknown and non-structural environment, such as ocean exploration, militaryreconnaissance, nuclear power plant maintenance and ruins rescue. The research onself-reconfigurable modular robot can not only extend the application field of robotics,but also have important significance for improving the level of scientific research in thisfield.As for self-reconfigurable robot system, the movement of system depends on thedynamics of each module and the interaction between modules. According to thedynamic characteristic of self-reconfigurable robots, we provide dynamic cellularautomaton model, based on which we then point out the relationship between thereversibility of state transition rule matrix and cellular neighborhood. Furthermore, wediscuss the theory of group self-reconfigurable robots.Through reference on the environment-based modeling method of group systems t,the dynamics of robot modules can be simplified as higher-order linear time-invariantsystems. In consideration of mutual independence of modules, we analyze the dynamiccharacteristic of modular self-reconfigurable robots as discrete linear time-invariantsystems, and describe the state equations of system, which shows the uniformity ofkinetic equation and cellular automaton-based dynamic equation in terms of form.Furthermore, we point out that controllability of modular self-reconfigurable robotsdepend on the interaction between modules and the topological structure of systemdiagram; two factors are mutually independent and unrelated, but they must be metsimultaneously.Due to different emphasis made by domestic and foreign self-reconfigurable robots,there is still no universal simulation tool at present. This paper devotes to designing anddeveloping a simple and practical simulation environment for self-reconfigurable robot for the purpose of truly reflecting the movement of self-reconfigurable modular robotand reducing the constraints caused due to different hardware design of modules asmuch as possible. We take Microsoft Robotics Developer Studio as a development toolto abstract the robot modules into a cube, and add physical attributes such as quality,color, and friction coefficient on the cube. The virtual environment can truly reflect theoverturn and translation movement of robot under actual situation, which lays afoundation for future development.Currently, the existing distributed-type modular self-reconfigurable robots has alow-efficiency serial algorithm. In the research process of this project, we assign IDnumber for each robot number, describe the overall configuration of robots, and thenformulate the constraints of movement according to the action constraints of modulesunder real environment. Finally, according to the parallel characteristic of cellularautomaton, we propose parallel reconfiguration algorithm of modular self-reconfigurablerobots and carry out MATLAB simulation in consideration of collision avoidance in themovement process of modules on the basis of ensuring connectivity of system.