The ground-based Primordial Gravitational Wave Telescope is designed to detect radiation in the microwave band, but physical noise sources fluctuations can interfere with the detection of gravitational waves, leading to reduced transient sensitivity and data collection gaps. This type of observation requires highly accurate and stable equipment to capture and interpret weak signals. Traditional telescopes often rely on dome structures for protection. For the Ali Primordial Gravitational Wave project in China, a unique environmental protection cover was proposed to protect the telescope. One major difference between this telescope and traditional optical telescopes is the movement range of its altitude axis (Fig.1). To accommodate the motion range of the Ali telescope, this paper focuses on the design of the altitude axis system and its control strategy.The study first designs the motion and structural scheme for the altitude axis of the protection cover based on the telescope's unique motion pattern (Fig.2). A contact model and a friction model were established, followed by dynamic simulations. Based on the simulation results (Fig.6), a torque compensation dual-motor control strategy targeting specific positions was developed for the environmental protection cover. Additionally, for the non-linear complexity of the altitude axis system, a control strategy using SAPSO-BP-PID was designed for the active motor to enhance system robustness (Fig.9). The designed system uses a retractable roller-shutter structure instead of a traditional dome, ensuring protection while maintaining the telescope’s observation range. Dynamic simulations show that when only one motor drives the system, three main stages occur roller convergence and clearance compensation, normal operation, and eventual stall or loss of control (Fig.6). Simulation results indicate that, with a 1 (°)/s step signal as the reference input and an external load applied at a certain point to simulate disturbances, the SAPSO-BP strategy achieves a smaller overshoot and shorter settling time during the initial startup phase compared to other strategies with similar response times. Under disturbance conditions, the SAPSO-BP strategy demonstrates superior peak error suppression, resulting in lower mean error and integral of squared error (ISE) (Fig.11). Despite error fluctuations caused by system delays and model simplifications, the proposed dual-motor control strategy, combined with the SAPSO-BP-PID controller for the active motor, ensures effective tracking performance. The integral of speed tracking error under various reference speed curves consistently meets the design requirements (Fig.12-Fig.19).The environmental protection cover system for the altitude axis proposed in this paper meets the requirements for large-range motion of the altitude axis of the Ali Primordial Gravitational Wave Telescope. The system adopts a dual-roller shutter structure, allowing the observation window to rotate freely within the altitude angle range of 45° to 135°. To achieve precise control, a torque compensation dual-motor control strategy based on target position was designed, and an SAPSO-BP-PID controller was developed by leveraging the global search capability of SA and the fast convergence ability of PSO. Simulation results show that under the same reference input and disturbance conditions, the SAPSO-BP strategy exhibits higher control accuracy compared to the PSO-BP strategy, maintaining smaller overall error during dynamic system changes. Therefore, the SAPSO-BP strategy outperforms the PSO-BP strategy in terms of dynamic response, error control, and disturbance rejection. Across various reference speed curves, the dual-motor control strategy, combined with the SAPSO-BP-PID controller for the active motor, effectively achieves coordinated allocation and stable operation of the master and slave motors. Despite error fluctuations caused by system delays and model simplifications, the strategy demonstrates excellent tracking performance in terms of response speed and overshoot. The integral of speed tracking error consistently meets the design requirements. The system design satisfies the performance needs for high-precision and large-range motion of the telescope, demonstrating its effectiveness and robustness.