An explicit modelling method of joint-space inertia matrix for tree-chain dynamic system

The joint-space inertia matrix (JSIM) plays an important role in the dynamic simulation and control of robot mechanisms. In this paper, a novel explicit modelling method of JSIM for tree-chain dynamic system is proposed. By this method, each element of the inertia matrix has an explicit expression with respect to input parameters. Thus, the modelling process only includes the process of coordinate system establishment and parameter determination without the intermediate process of complex analysis and derivation. Moreover, the matrix elements are decoupled, which is beneficial to further study of the properties of JSIM on the one hand. On the other hand, multiple matrix elements can be computed simultaneously to reduce the computation time. Compared with the existing explicit method, this method has higher modelling and computational efficiency. Finally, a planar manipulator with three degrees of freedom (DOFs) is used to verify the proposed method in serial-chain application and show its modelling convenience. A lunar rover example is used to verify the proposed method in tree-chain application, and the modelling results are applied to the traction control in the simulation software of lunar rover. •This paper proposes a novel explicit modelling method of JSIM for tree-chain dynamic system.•The expression of JSIM element is explicit and decoupled.•The symmetry property of JSIM is proved mathematically.•The parallel computing of JSIM elements is easily implemented.•This method has higher modelling and computational efficiency than the existing explicit methods.