Base position planning of mobile manipulators for assembly tasks in construction environments

With good mobility and flexibility,mobile manipulators have shown broad applications in construction scenarios.Base position(BP)planning,which refers to the robot autonomously determining its working station in the environment,is an important technique for mobile manipulators when performing the construction assembly task,especially in a large-scale construction environment.However,the BP planning process is tedious and time-consuming for a human worker to carry out.Thus,to improve the efficiency of construction assembly tasks,a novel BP planning method is proposed in this paper,which can lead to appropriate BPs and minimize the number of BPs at the same time.Firstly,the feasible BP regions are generated based on the grid division and the variable workspace of the mobile manipulator.Then,the positioning uncertainties of the mobile manipulator are considered in calculating the preferred BP areas using clustering.Lastly,a set coverage optimization model is established to obtain the minimum number of BPs using an optimization algorithm according to the greedy principle.The simulated experiment based on a 9-degree of free(DoF)mobile manipulator has been performed.The results illustrated that the time for BP planning was significantly reduced and the number of BPs was reduced by 63.41%compared to existing manual planning,which demonstrated the effectiveness of the proposed method.