Monitoring and Experimental Study on Dynamic Characteristics of Truss Robot

This paper proposes an integrated research method that integrates rigid flexible coupling dynamic modeling, finite element analysis, and dynamic monitoring experiments to address the problems of dynamic performance degradation and insufficient motion accuracy caused by structural flexibility of truss robots under high-speed and heavy load conditions. Firstly, the rigid flexible coupling model is constructed through the cooperation of the multi-body dynamics software RecurDyn and the finite element software ANSYS: the beam is reduced by using the modal flexible body (RFlex), and the sliding platform is retained by using the finite element flexible body (FFlex) to retain local deformation details, which solves the problem of balancing the accuracy and efficiency of the traditional single model. Simulation shows that the flexibility effect leads to a maximum displacement deviation of 0.45 mm in the X/Z direction at the end. Further reveal the weak links in the structure through statics and modal analysis: the X/Z static stiffness of the crossbeam and column (7.91-9.08 MPa) is significantly lower than that in the Y direction (6.46 MPa), and there is a risk of resonance between the low order natural frequency (15.92-52.63 Hz) and the servo motor excitation frequency band. The dynamic monitoring experiment based on three-axis acceleration sensor and frequency domain integration algorithm shows that when the speed is increased to 0.3 m/s, the X/Z directional vibration displacement increases by 68% and 52% respectively compared to the 0.1 m/s working condition, while the load increase to 7 kg only significantly affects the X directional vibration during the horizontal motion stage.