The motion controller based on PCI bus is widely used in telescope and robot control. In this paper, a multi-axis PCI bus motion controller is used to control the folding and unfolding model of large-caliber space telescope. The hardware system design and software system development are carried out separately. The actual control results show that the whole motion control system can satisfy the control requirements of the folding and unfolding model of the space telescope very well. This method is simple to implement and easy to debug. The practical application of folding and deployment of Space Telescope has laid a good foundation in the future. In order to reduce the size of large-aperture space telescope when launching, and realize the precise positioning and locking of the sub-mirror unit after the primary mirror is deployed in the air, release its deployment power and the power source of each link locking, this system designs a conceptual design of foldable deployable primary mirror for large-aperture space telescope.
The whole telescope model is folded and unfolded by seven stepper motors, and the locking state is satisfied after the power source is removed. The motion controller based on PCI bus is a PCI bus based on PC. It has an open architecture combined with PC to control the position, speed and acceleration of servo or stepper motor. Motion controller usually uses special motion chip or tells DSP to complete trajectory planning, curve interpolation, servo control and standardized communication interface control functions. Users can call the library function of the motion controller to develop the corresponding application program according to their needs.
It is convenient to realize various motion control functions. The control object is monitored in real time on the designed human-machine interface. The motion control card is easy to use. Therefore, it has important applications in the fields of telescope control, robots and so on. In order to realize the automatic control of folding and unfolding control system of large-caliber space telescope, the control system uses industrial computer, PCI multi-axis controller, stepper motor driver and stepper motor to construct the whole control system.
The computer controlled motion controller sends a pulse signal to the stepper motor driver. The driver drives the stepper motor to rotate at a certain angle.
The output shaft of the stepper motor drives the drive mechanism to move. The precise positioning and control of the stepper motor are realized by pulse mode. Multi-axis stepper motor motion controller adopts GTS-800-PG-PCI series motion controller produced by Gu Hi-tech Co., Ltd., which can realize high-speed point motion. Its core is composed of DSP and FPGA, which can realize high performance control calculation.
It is suitable for a wide range of applications, including robots, CNC machine tools, woodworking machinery, printing machinery, assembly line, electronic processing equipment, laser processing equipment and PCB drilling and milling equipment. GTS-800-PG-PCI series motion controllers are based on industrial control computers and provide standard PCI bus products.
Motion controller provides matching motion debugging software, C language function library and Windows dynamic link library, which can realize complex control functions.
These control functions can be integrated with application modules such as data processing, interface display, user interface and so on, which are needed by the control system itself. The control system that meets the specific application requirements can be built to meet the requirements of various application fields. Motion controller provides two different control signals: positive/negative pulse and pulse direction. When controlling stepper motor, the control mode is open-loop control. The stepper motor adopts 60STH101-3004A stepper motor and 2H606M series stepper motor driver of Weitong Electrical and Mechanical Manufacturing Co., Ltd. The parameters of motor and driver are shown in Table 1.
85,86,110 series of two-phase hybrid stepping motors; working environment: -10-55 degrees C, 15-85% RH; subdivision: 200-60 000 steps/turn, a total of 28 micro-step subdivision; signal interface and timing: common anode, common cathode and differential signal three connection methods, the system uses differential signal connection method as shown in Figure 1.
GTS-800-PG-PCI series motion controllers provide users with corresponding debugging software MCT2008, which is also convenient for secondary development. Under Windows system, users can use any development tools that can support dynamic link library to develop applications, support Visual C , Visual Basic and Delphi applications.
In this system, thermostatic element we use Microsoft Visual Studio 2010 for secondary development. Before using motion controllers for various operations, we need to configure motion controllers so that the state and working mode of motion controllers can meet the requirements. Using the configuration component of Motion Controller ToolKit 2008, the corresponding configuration file *. CFG is generated. When programming, the configuration information is transferred to the motion controller by calling relevant instructions, and the configuration of the whole motion device can be completed. The basic configuration of the stepping control mode of the system is shown in Figure 2. The planned position of Profile output enters axis. After equivalent transformation in axis, it outputs to step, which generates control pulses and drives the motor. Axis needs to drive some digital output signals such as alarm, positive limit signal, negative limit signal, smooth stop signal and emergency stop signal to manage the motion. At the same time, axis needs to output servo signal to digital output to enable the motor to function. The interface of motion control management software is shown in Figure 3.
GTS motion controller can work independently in point position, Jog, PT, PVT, electronic gear or Follow motion mode (electronic cam). Under this control system, we adopt point position control mode. The control system interface is shown in Figure 4. The experimental results show that the whole motion control system can satisfy the control requirements of the folding and unfolding model of the space telescope well by selecting the motion controller based on PCI bus and using Visual C to redevelop the motion controller. Moreover, it is easy to debug and lays a good foundation for the practical application in the future.