Industrial Internet of Things (IIoT) is one of the most important application scenarios of the fifth generation mobile communication. In IIoT applications, the propagation channel differs significantly from the propagation environment of the typical cell communication system. In this paper, two special propagation cases are considered. The sensors/actuators (together with the RF transceiver) sometimes are equipped on the swinging mechanical robot arms (MRAs) and on moving automated guided vehicles (AGVs), which have never been thoroughly investigated, and hence the wireless channel between the sensor/actuator and control center becomes time-varying when the MRA is working and vehicles are moving. A two-dimensional geometrical model for the MRA and a mathematical model of random Doppler offset for AGVs are provided to depict these Doppler frequency trajectories in the industrial propagation environment. By using the realistic measurement data, these Doppler frequency trajectories are verified and the simulated results show good agreements. The established models are informative to design wireless networks for industrial scenarios.