Study On Tracked Mobile Robot With Manipulator In Complex Terrain

With the gradual improvement in the robot technology, application field of the mobile robot become from the indoor structured environment to the outdoor unstructured environment. They are employed in mine disaster and city ruin rescue, engineering exploration, anti-terrorism, batter field and aerospace exploration. In these fields, some special design and analysis method should be used to improve trafficability. So in this paper, the interaction of track-terrain, vibration dynamic model of mobile manipulator, accurate and highly efficient algorithms for mobile manipulator non-stationary random responses, motion planning and stability analysis of climbing up an obstacle are introduced.The mobile robot system is designed by the module partition method which makes the robot serialization and standardized. Some special designs are used for the unstructured environment, such as suspension system, anti-explosive and radiation protection and waterproof. And then the kinematics model of mobile manipulator is built. Using this model, the geometry parameters identified method and trajectory planning method of mobile manipulator are obtained.The effect of the terrain physical parameter on the trafficability in the soft terrain is presented. The interaction model of robot track and terrain are built based on terramechanics. At first the track system is divided into three partitions, namely front road wheel, middle track and the rear road wheel. In the different partition, the terrain state under the track is in the different process of loading, unloading and reloading. So the models in the different partitions are different. And then the three parts are connected on the common point by the force balance, and the whole model of the track system is obtained. Using this model the effect of the track parameters on the trafficability is analyzed, and the maximum drawpull which the terrain can afford is obtained. At last the experiments plat is introduced, and some experiments are design to validate the vibration dynamic model and the analysis results. These results are valuable for the design of the all terrain mobile robot.The random vibration due to road roughness has some effect on mobile manipulator. The reliability and the stability are reduced. First vibration dynamic model of the mobile plat is built by the Lagrange model, and the dynamic model of the manipulator is built with finite element method (FEA). And then the two models are rebuilt into whole model of the mobile manipulator by the force balance on the common point. Using the accurate and highly efficient pseudo-excitation method (PEM), precise time-integration and the vibration dynamic model, the transient power spectral density (PSD) of vehicle in nonstationary random vibration exicitation is obtained. For different parameters of the suspension and different posture of manipulator, the performance of the vibration absorbing is analyzed. These results can guide design the suspension of the mobile manipulator.Because the center of gravity (CG) plays an important role in the process of climbing up an obstacle, the CG kinematics model is built. Especially the effect of the manipulator postures is included. Using this model, the CG change situation is obtained in the process of climbing an obstacle, and the maximum height of the obstacle which can be climbed up is obtained, and the stability angle margin is obtained too. At last the relationship between the posture of the manipulator and the height of the obstacle which can be climbed is obtained.The dynamic performance of the mobile manipulator affects the obstacle-climbing performance. So the dynamic model of the mobile manipulator is built by the Newton-Euler method. Using the dynamic model and zero moment point (ZMP), dynamic effect of the mobile manipulator on the robot stepping over a ditch and climbing up an obstacle are presented. The optimal accelerations of the mobile manipulator and the robot are obtained by the dynamic model. At last the compare of obstacle performance of the robot in the case of no any motion planning, kinematics motion planning and dynamic motion planning is obtained.Finally, several experiments are designed for the trafficability analysis of the mobile manipulator. The grasping test of mobile manipulator, the vibration test in the rough terrain and the autonomous motion planning of climbing up an obstacle are designed. These test results validate the analysis results.