Research On Servo System With Multiple Position Interfaces Based On TMS320F28377S

With the gradual improvement of the modern industries,more and more requirements are put forward for the servo system.In this paper,a servo control system with high performance and multiple position interfaces is designed based on TMS320F28377S,through the research of various position detection and related problems.Firstly,based on high-performance chip TMS320F2837S,a dual position solving system is designed,including position solving system of the absolute photoelectric encoder and the resolver.The system use SCI module to communicate with encoder,receive and decode the high speed serial data stream returned by the encoder,and obtain position;With ADC module,the output signal of the resolver is 160 times over sampled and phase-sensitive rectified to improve the position decoding precision of the resolver,and relevant data are processed by CLA,which is used to coordinate the high frequency of ADC samples and low frequency CPU's data-fetch.The system uses only one high-speed DSP to accomplish the position-solving of the two position sensor,with no need of special decoding chip neither FPGA,the experimental results show that the two kinds of position solving system have good performance index,in which the position decoding precision of the resolver reaches ±0.1°.Secondly,the above position solving system is applied to the multi-level transmission system with higher transmission ratio,absolute photoelectric encoder and resolver are installed on the first and end of the transmission system respectively.How to monitor and repair the position of the photoelectric encoder according to the position of the resolver is analyzed,to improving the decoding security,the overload monitoring and the overall precision.At last,the no position sensor control method of brushless DC motor is studied,and an improved back EMF zero-crossing method is proposed.In the middle and low speed,the classical back EMF zero-crossing method is used,the motor can commutate correctly for its low phase delay.In the high speed,the correlative state of the ePWM module's comparator is used as the trigger signal of the terminal voltage sampling,without the filter or comparison circuit.The experiments show that the method can achieve BEMF zero-crossing detection accurately and can be used in high-speed and high-frequency occasions.