Design And Motion Analysis Of Variable Tracked Mobile Robot

In recent years, the deterioration of the natural environment and a great of geologicaldisaste make the mobile robot to be important for search and rescue in the ruins. In order toadapt to the complicated environment, too many structure and movement modes of the robothas been developed from the single to the composite structures. The obstacle crossing abilityand stability of composite variable robot with multi-movement modes are importanttheoretical and practical key in complex unstructured environments.According to the disaster environment, a variable parallelogram tracked mobilerobot(VPTMR) is proposed and developed, which applys double legs’s alternative motion ofprinciple and roller skating. The VPTMR robot consists of two variable parallelogramstructures, which are composed of one main tracked arm, two lower tracked arms and a chasis.The variable parallelogram structure is actuated by a DC motor. And another DC motoractuates the track rotation, which enables VPTMR robot to move in wheeled, tracked andlegged mode that makes the robot to adapt to different environments.On actuation design of the VPTMR, internal and external shafts are designed to drive theswing arm and the main crawler. The dead point of parallelogram mechanism is eliminated byusing the synchronous driving of double-crank. The center gravity trajectory of robot duringtransfiguration is analyzed. The stability of the robot is analyzed in the conversion ofmovement pattern by optimizing the length of the main track and the swing arm track.The statics of VPTMR robot is built in both wheeled mode and main tracked mode. Theoptimal movement posture is presented in a straight line and uniform velocity. Simulations ofthe typical movement modes of this robot are built by ADAMS software. These simulationalresults show that the motor torque changes in the movement.Some experiments are done for testing motion performance of typical movement and thesituation of variable mechanism during conversion movement pattern. The results of theseexperiments verified the design of variable mechanism, its transmisssion system, synchronousdrive mechanism and geometrical optimization of the main track and the swing arm track are reasonable. All the above design and analysis prove that the design of VPTMR robot isreasonable and practical.