The mechanical phased array antenna adopts spiral antenna as the radiation unit,and achieves a predetermined radiation phase through the mechanical rotation of the helical antenna unit to achieve directional radiation and beam control of microwaves.The drive equipment such as a motor is connected with the spiral antenna,and the displacement of the spiral antenna is realized by driving the motor to rotate,thereby realizing phase radiation control.As an important part of the mechanical phased array antenna,the performance of the motor control system directly affects the phase-shifting speed and positioning accuracy of the unit antenna,which in turn affects the overall performance of the mechanical phased array antenna.Stepper motor is an actuator that converts digital pulse sequences into angular displacement increments.It has the characteristics of low cost,rapid start and stop,and high positioning accuracy,so it is suitable for driving control of mechanical phased array antennas.The stepper motor is used as the antenna control drive unit.Aiming at the problem that the acceleration and deceleration curve start from zero-velocity(static)is difficult to fully exert control performance,a linear acceleration and deceleration curve of the stepper motor start from a certain velocity is proposed.The algorithm uses the self-start and stop rate of the stepper motor to control the motor to start or stop from a certain speed.The acceleration torque required during the acceleration process is smaller,and the chattering is smaller in the medium and high velocity.The acceleration and deceleration process is divided into four rotation modes,including uniform rotation mode,uniform acceleration rotation mode,uniform deceleration rotation mode and uniform deceleration zero-crossing rotation mode.The control pulse period of the four rotation modes is theoretically derived,and the four modes can be constructed arbitrary linear velocity profile,with strong flexibility of use.In order to realize control of stepper motor start and stop from a certain velocity,the IP core of stepper motor controller is designed in FPGA.Using Verilog hardware description language,the stepper motor controller IP core is designed,including curve algorithm,interface,pulse generation and position detection function modules.In order to realize the low power consumption of the IP core,the hardware logic model of the acceleration and deceleration curve algorithm is optimized in combination with the pipeline design idea,and the low-power IC design technology such as clock gating is adopted.The IP core is simulated by Modelsim software,and the simulation results show that the design is correct and the control precision is high.In order to research control performance of single-axis stepping motor,a two-phase hybrid stepping motor experimental platform was built.The control of four rotation modes start and stop from a certain velocity is tested,and any linear speed profile can be realized.The experimental results show that compared with the IP core of the stepper motor controller start from zero-velocity(static),this scheme can improve the control performance of the motor by 20%,optimize the circuit area by about 30%,and reduce the power consumption by 53%.In order to verify the multi-axis servo drive controller scheme,a 30-channel motor control system is constructed to realize the synchronous drive control of multi-axis motors.The embedded soft core Nios Ⅱ reads and writes the multi-channel motor IP core registers through the Avalon bus to achieve the purpose of real-time control of the multi-axis motor rotation.An experimental platform is built to realize high real-time and high precision driving of multi-axis motors.The experimental results show that the independent and synchronous drive control of 30-axis stepper motors can be realized,which verifies the feasibility and effectiveness of the scheme. |