The motor rotor and the gear shaft 1, the gear shaft 8 and the sun gear of the first stage planetary gear train, the planetary carrier of the second stage planetary gear train and the roller are connected through the elastic torque shaft. The elastic torque shaft only transmits torque and can be regarded as a linear elastic connection in the degree of freedom. Taking linear elastic connections with stiffness attributes K1 and K2 added to the first and third degrees of freedom, the second and fifth degrees of freedom as examples (assuming that the number of degrees of freedom of the system is 5), the matrix operation is described.
In the formula, the first and third degrees of freedom connected by K1, the second and fifth degrees of freedom connected by K2, and the number of degrees of freedom refer to the number after adding the rigid connection. It should be noted that due to the deletion of repeated degrees of freedom after adding rigid connection, the total number of degrees of freedom of cutting transmission system will be reduced, and the global number of corresponding node degrees of freedom of each substructure will be reduced in turn. Since the calculation process of updating the global number of degrees of freedom is not complicated, it is omitted here. The calculation method of cliis similar to equation (2.51), so it will not be repeated.