| Multi-robot transportation refers to the use of multiple mobile robots to transport the same object cooperatively.It has potential application prospects in large-scale object handling,logistics industry,industrial production,natural disaster rescue and other fields.The core is to plan a collision-free path to transport the object smoothly from the starting point to the target point.Aiming at the problem that the existing algorithms rarely consider the state of the transported object,this paper studies the multi-robot distributed cooperative transportation problem by introducing the interaction force between the robot and the transported object.The main contents are as follows :(1)By considering the contact force between the robot and the transported object,a multi-robot cooperative transportation control algorithm based on adaptive decentralized controller is given,and the condition that the load of each robot is relatively balanced during transportation is obtained.In this paper,the contact force between the robot and the object is used as the communication condition,and the contact force between the robot and the object is modeled as the gradient of the nonlinear potential describing the deformation of the object.Then the robot can adaptively estimate the speed of the whole team without giving the desired speed by constantly adjusting the contact force,so that the robot and the object can reach the desired speed and converge to the same.Secondly,a mass estimator is designed to estimate the mass of the unknown object,so that the sum of the mass estimation of each robot is also close to the real mass of the object.The stability of the system is proved by Lyapunov theory.Finally,the speed changes of the robot and the object in three different directions are analyzed by simulation,and the estimation of the quality of the object by the robot is analyzed.The results show that the proposed algorithm can achieve the expected goal,which is more in line with the needs of the actual environment and has good transportation performance.(2)On the basis of the above work,considering the multi-robot cooperative transportation problem with obstacles in the environment,a multi-robot formation transportation algorithm based on consistency theory is proposed.The object is placed on the top of the robot and transported.The robot adjusts the position between each other through the distance,so that the object is evenly distributed at the top of the robot.The robot forms a formation according to the shape of the object,then the center of the object coincides with the robot formation frame,so that the top of the robot is evenly stressed.After the object is loaded,in order to keep the force between the robot and the object relatively stable,a distance-based controller is proposed to make the robot form a formation while maintaining a good formation.When encountering obstacles during transportation,the robot takes into account the information of the neighbor robot and increases the detection range,so that the robot can predict the obstacle information in advance,predict and avoid obstacles in advance,and maintain a good formation.Finally,a virtual navigation angle is introduced to form an angle difference with the target point of transportation,so as to obtain the navigation angle of the real robot transportation team.Finally,the robot can accurately navigate to the desired target point.Stable and efficient completion of transportation tasks.Finally,the simulation results show that the proposed algorithm is effective.At the same time,compared with other algorithms,the algorithm has the advantage that the robot quickly forms a formation shape according to the shape of the object,and maintains a good formation during the obstacle avoidance process.Finally,the robot team can accurately reach the desired target point,making the multi-robot more stable.Transport objects,so it is more in line with the needs of the actual environment and has good transportation effects. |
