Design of tunnel steel arch looping manipulator with multiple actuators in limited space

In order to overcome the low efficiency, high labor intensity and high risk of steel arch support operations in tunnel boring machines, a steel arch looping manipulator with multiple actuators was designed. Firstly, in order to simplify the complex design requirements of the manipulator, an exponential product model was established to analyze the influence of each single joint on the end output, and the manipulator was decomposed into different modules. The design is carried out separately, layer by layer, in the order of actuator—trunk module—branch module. Then, the optimal manipulator is obtained considering the limited space, equivalent flexibility, and joint control accuracy requirements. Finally, a prototype of the steel arch looping manipulator was manufactured and the feasibility of the manipulator was verified by experiments. The design method can provide a reference for the design of multi-actuator manipulator configuration in limited space.