Position control for sliding roof systems to reduce vibration

This paper presents a time-based instantaneous position control scheme for a sliding roof system driven by a permanent magnet synchronous motor (PMSM) to reduce the mechanical vibrations of the structure. The proposed algorithm consists of two reference generators. The first generator is used to determine the roof movement pattern and the maximum speed of the motor, which become the inputs of the second generator. The second generator takes these values and gives out an instantaneous rotating speed reference to the motor and an instantaneous roof position reference. The acceleration/deceleration patterns made by the first generator follow the shape of a cosine function to minimize vibration. Furthermore, the instantaneous roof position reference is compared to the actual value obtained with a motor encoder to calculate the position error, which becomes an input for the speed controller of the PMSM. First, a detailed analysis of a sliding roof system and the proposed control method are presented. Then, a PMSM was installed to an actual sliding roof system and experiments were done to verify the proposed method. Both simulation and experiment results show that the sliding roof moves smoothly with less vibration and that the proposed position control produces a more precise result when compared to that of the conventional method.