A high-precision equal-step control device

Abstract

The present invention discloses a high-precision equal-step control device, which relates to the field of position control technology. The device comprises a clock unit, an angle measuring unit, a control unit, and a drive unit. The clock unit is electrically connected to the angle measuring unit and the control unit. The clock unit generates a clock pulse and synchronously sends the clock pulse to the angle measuring unit and the control unit. The angle measuring unit is electrically connected to the control unit. The angle measuring unit sends the calculated angle code to the control unit. The control unit calculates the control deviation. The control unit is electrically connected to the drive unit. The control unit generates a drive pulse and sends it to the drive unit. The drive unit synchronously receives the control deviation to complete drive control. The present invention has the advantage that using equal-step pulses as interrupt control pulses for the speed loop and the position loop can effectively eliminate acquisition errors and transmission errors in shaft angle data, thereby improving the control accuracy of the speed loop and the position loop.

Description

Technical Field

[0001] The present invention relates to the technical field of position control, and in particular to a high-precision equal-step control device. Background Art

[0002] As a kind of high-precision test equipment, turntables and rocking tables have extremely high requirements for rate accuracy and position accuracy. Traditional turntables and rocking tables use separate angle measurement systems, drive systems, computers and interface units to complete the control of turntables and rocking tables. It is inevitable that there will be reading errors, transmission errors and control errors in the axis angle data. Summary of the Invention

[0003] In order to solve the above technical problems, a high-precision equal-step control device is provided. This technical solution solves the problem that the turntable and rocking table proposed in the above background technology are high-precision test equipment, which have extremely high requirements for rate accuracy and position accuracy. Traditional turntables and rocking tables use separate angle measurement systems, drive systems, computers and interface units to complete the control of the turntables and rocking tables, and inevitably there are problems of reading errors, transmission errors and control errors in the axis angle data.

[0004] In order to achieve the above objects, the technical solution adopted by the present invention is:

[0005] A high-precision equal-step control device includes a clock unit, an angle measuring unit, a control unit, and a drive unit. The clock unit is electrically connected to the angle measuring unit and the control unit. The clock unit generates clock pulses and synchronously sends the clock pulses to the angle measuring unit and the control unit. The angle measuring unit is electrically connected to the control unit. The angle measuring unit sends a calculated angle code to the control unit. The control unit calculates a control deviation. The control unit is electrically connected to the drive unit. The control unit generates a drive pulse and sends it to the drive unit. The drive unit synchronously receives the control deviation to complete drive control.

[0006] Preferably, the angle measuring unit includes an outer ring angle measuring unit, a middle ring angle measuring unit and an inner ring angle measuring unit; the clock unit is electrically connected to the outer ring angle measuring unit via inverters U2A and U2B; the clock unit is electrically connected to the middle ring angle measuring unit via inverters U2C and U2D; the clock unit is electrically connected to the inner ring angle measuring unit via inverters U2E and U2F; the outer ring angle measuring unit, the middle ring angle measuring unit and the inner ring angle measuring unit respectively generate outer ring shaft angle data, middle ring shaft angle data and inner ring shaft angle data, and send them to the control unit.

[0007] Preferably, the inverter U2A, the inverter U2B, the inverter U2C, the inverter U2D, the inverter U2E and the inverter U2F are all of model SN74LS04D.

[0008] Preferably, the drive unit includes an outer ring drive unit, a middle ring drive unit and an inner ring drive unit, and the control unit is electrically connected to the outer ring drive unit, the middle ring drive unit and the inner ring drive unit through independent signal ports. The control unit calculates the outer ring control deviation, the middle ring control deviation and the inner ring control deviation according to the outer ring shaft angle data, the middle ring shaft angle data and the inner ring shaft angle data, and generates an outer ring servo control pulse, a middle ring servo control pulse and an inner ring servo control pulse. The inner ring servo control pulse is used to synchronize the inner ring drive unit, and the inner ring drive unit receives the inner ring control deviation EZ output by the control unit to complete the control of the inner ring shaft. The middle ring servo control pulse is used to synchronize the middle ring drive unit, and the middle ring drive unit receives the middle ring control deviation output by the control unit to complete the control of the middle ring shaft. The outer ring servo control pulse is used to synchronize the outer ring drive unit, and the outer ring driver receives the outer ring control deviation output by the control unit to complete the control of the outer ring shaft.

[0009] Preferably, the control unit includes an FPGA processor and a DSP processor, and the FPGA processor and the DSP processor are electrically connected through an SRIO interface. The FPGA processor implements logic and interface functions as well as programmable fixed operation functions, and the DSP processor implements the control functions of the speed loop and position loop of the turntable. The FPGA processor generates synchronization pulses, control shaft angle data latch pulses, and synchronous recording shaft angle data latch pulses. The shaft angle data latched by the control shaft angle data latch pulses is used by the controller to read the shaft angle feedback data, and the control deviation is calculated according to the control quantity given by the human-machine interface or remote control instructions. The synchronous recording shaft angle data latch pulses are used to latch the shaft angle data.

[0010] Preferably, the control unit also includes a data output interface, a remote control interface and an external synchronization pulse input interface. The data output interface is an RS422 serial interface, which is used to send three-axis angle synchronization data latched by synchronization pulses to the user device. The remote control interface is used to receive remote control instructions sent by the user remotely to realize the remote control function of the turntable. The external synchronization pulse input interface is used to receive the synchronization signal sent by the user to the turntable controller.

[0011] Compared with the prior art, the advantages of the present invention are:

[0012] The present invention adopts a unified high-precision clock as the clock reference of the equal-step controller. The shaft angle data solution, data acquisition, data transmission, speed loop, position loop control step pulse, synchronous acquisition latch pulse, angular position reading latch pulse, and synchronization pulse for the user are all generated by dividing the reference clock. Therefore, the errors caused by the data acquisition and data transmission links can be eliminated, and the jump errors caused by the interference pulses can also be eliminated. The step pulses generated by the clock reference division are used to control the speed loops and position loops of the three axes, so that the control cycle is on the same edge as the angle solution cycle and the data acquisition cycle, ensuring that the update of the shaft angle data is synchronized with the control cycle, which can eliminate the errors in the control quantity calculated by the speed loop and the position loop, thereby improving the control accuracy of the speed loop and the position loop. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a principle block diagram of the present invention;

[0014] Figure 2 This is a schematic diagram of the control pulse generator of the present invention;

[0015] Figure 3 This is a timing diagram of the control pulse generator of the present invention;

[0016] Figure 4 is a circuit diagram of the angle measuring unit of the present invention;

[0017] Figure 5 is a circuit diagram of the driving unit of the present invention. DETAILED DESCRIPTION

[0018] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0019] Reference Figure 1-3 As shown, a high-precision equal-step control device includes a clock unit, an angle measuring unit, a control unit and a drive unit. The clock unit is electrically connected to the angle measuring unit and the control unit. The clock unit generates a clock pulse and synchronously sends the clock pulse to the angle measuring unit and the control unit. The angle measuring unit is electrically connected to the control unit. The angle measuring unit sends the calculated angle code to the control unit. The control unit calculates a control deviation. The control unit is electrically connected to the drive unit. The control unit generates a drive pulse and sends it to the drive unit. The drive unit synchronously receives the control deviation to complete drive control. The controller receives user instructions, collects shaft angle data of the angle measuring unit, calculates the control deviation according to the given quantity and feedback quantity according to the control model, and outputs it to the drive unit to complete closed-loop control of the speed loop or position loop.

[0020] The control unit includes an FPGA processor and a DSP processor. The FPGA processor and the DSP processor are electrically connected through the SRIO interface. The FPGA processor FPGA realizes logic and interface functions as well as programmable fixed operation functions. The DSP realizes the control functions of the speed loop and position loop of the turntable. The FPGA processor FPGA frequency division generates programmable 1Hz, 10Hz, 100Hz, 200Hz, 1KHz internal synchronization pulse TT, control shaft angle data latch pulse LCK1, synchronous recording shaft angle data latch pulse LCK2, inner loop servo control pulse PZ, middle loop servo control pulse PY, and outer loop servo control pulse PX. The internal synchronization pulse can be programmed to generate TTL level rising edge valid pulses of different frequencies such as 1Hz, 10Hz, 100Hz, 200Hz, 1KHz according to the input of the human-machine interface or the requirements of the remote control command. The shaft angle data latched by the control shaft angle data latch pulse LCK1 is used by the controller to read the shaft angle feedback data. According to the control amount given by the human-machine interface or remote control command, the control deviation is calculated and output to the inner ring drive unit M1, the middle ring drive unit M2, and the outer ring drive unit M3 respectively to complete the closed-loop control. The shaft angle data latch pulse LCK2 for synchronous recording is used to latch the shaft angle data and record it into the synchronous recording device.

[0021] The angle measuring unit includes an outer ring angle measuring unit, a middle ring angle measuring unit and an inner ring angle measuring unit. The clock unit is electrically connected to the outer ring angle measuring unit through inverters U2A and U2B. The clock unit is electrically connected to the middle ring angle measuring unit through inverters U2C and U2D. The clock unit is electrically connected to the inner ring angle measuring unit through inverters U2E and U2F. The outer ring angle measuring unit, the middle ring angle measuring unit and the inner ring angle measuring unit generate outer ring shaft angle data, middle ring shaft angle data and inner ring shaft angle data respectively, and send them to the control unit. The models of inverters U2A, U2B, U2C, U2D, U2E and U2F are all SN74LS04D. The controller receives user instructions and collects the data of the inner ring angle measuring unit F1, the middle ring angle measuring unit F2 and the inner ring angle measuring unit F3. Unit F2 and the outer-loop angle measurement unit F3 use the given and feedback values ​​to calculate control deviations (outer-loop control deviation EX, middle-loop control deviation EY, and inner-loop control deviation EZ) according to the control model. Clock pulses are shaped by inverters U2A and U2B, U2C and U2D, and U2E and U2F before being sent to the outer, middle, and inner-loop angle measurement units, respectively. These serve as the reference clock for angle calculation. Because they use the same clock, the angle codes calculated by the outer, middle, and inner-loop angle measurement units are edge-aligned with the control readout latch pulse LCK1, the synchronous readout latch pulse LCK2, and the inner, middle, and outer-loop servo control pulses PZ, PY, and PX, thus avoiding acquisition and transmission errors. At the same time, the angle feedback value of each control cycle corresponds to the step pulse, avoiding calculation errors caused by the forward, backward or lost feedback angle reading. In other words, the calculation errors of the inner loop control deviation EZ, the middle loop control deviation EY, and the outer loop control deviation EX are eliminated, thereby improving the control accuracy and stability of the turntable speed loop and position loop;

[0022] See also Figure 4 As shown, the angle measurement unit controller uses the EPM7064AELC44-4 CPLD. A unified clock enters the chip through pin 43. In the figure, A0-A9 are address lines for addressing and reading angle measurement data, while D0-D7 are data lines for reading data. IOR is the read signal, IOW is the write signal, and AEN is the bus enable signal. Because the same 20MHz clock is used, the angle calculation data edges and the reading latch edges for each axis are the same as the master clock edges.

[0023] The drive unit includes an outer ring drive unit, a middle ring drive unit, and an inner ring drive unit. The control unit is electrically connected to the outer ring drive unit, the middle ring drive unit, and the inner ring drive unit through independent signal ports. The inner ring servo control pulse PZ is used to synchronize the inner ring drive unit. The inner ring drive unit receives the inner ring control deviation EZ output by the controller to complete the control of the inner ring shaft. The middle ring servo control pulse PY is used to synchronize the middle ring drive unit. The middle ring drive unit receives the middle ring control deviation EY output by the controller to complete the control of the middle ring shaft. The outer ring servo control pulse PX is used to synchronize the outer ring drive unit. The outer ring drive unit receives the outer ring control deviation EX output by the controller to complete the control of the outer ring shaft.

[0024] See also Figure 5 As shown, the drive unit uses a TI TMS320F2812 DSP. This controller uses a unified clock signal, input via pin 77, XCLKIN. This device also features an SPWM interface, making it convenient for controlling synchronous motors. PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 in the figure represent the PWM signals for motor control, while the remaining terminals are data and address lines. Because of the unified clock, the motor controller's read and write signals, as well as the data input and output signals, share the same edge as the digital signals from the main controller and the angle measurement unit, ensuring the same control cycle as the main controller. This enables equal-step, edge-matched control.

[0025] The control unit also includes a data output interface TD, a remote control interface RC and an external synchronization pulse input interface TR. The data output interface TD is an RS422 serial interface used to send three-axis angle synchronization data latched by synchronization pulses to the user device. The remote control interface RC is used to receive remote control instructions sent by the user remotely to realize the remote control function of the turntable. The external synchronization pulse input interface TR is used to receive the synchronization signal sent by the user to the turntable controller.

[0026] In summary, the advantages of the present invention are: using pulses of equal step length as interrupt control pulses for the speed loop and position loop can effectively eliminate the acquisition error and transmission error of the shaft angle data and improve the control accuracy of the speed loop and position loop.

[0027] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-precision constant-step control device, comprising a clock unit, an angle measuring unit, a control unit and a drive unit, characterized in that: The clock unit is electrically connected to the angle measuring unit and the control unit. The clock unit generates a clock pulse and synchronously sends the clock pulse to the angle measuring unit and the control unit. The angle measuring unit is electrically connected to the control unit. The angle measuring unit sends the calculated angle code to the control unit. The control unit calculates the control deviation. The control unit is electrically connected to the drive unit. The control unit generates a drive pulse and sends it to the drive unit. The drive unit synchronously receives the control deviation to complete the drive control. The angle measuring unit includes an outer ring angle measuring unit, a middle ring angle measuring unit, and an inner ring angle measuring unit. The clock unit is electrically connected to the outer ring angle measuring unit via inverters U2A and U2B. The clock unit is electrically connected to the middle ring angle measuring unit via inverters U2C and U2D. The clock unit is electrically connected to the inner ring angle measuring unit via inverters U2E and U2F. The outer ring angle measuring unit, middle ring angle measuring unit, and inner ring angle measuring unit respectively generate outer ring shaft angle data, middle ring shaft angle data, and inner ring shaft angle data, and send them to the control unit. The drive unit includes an outer ring drive unit, a middle ring drive unit and an inner ring drive unit. The control unit is electrically connected to the outer ring drive unit, the middle ring drive unit and the inner ring drive unit through independent signal ports. The control unit calculates the outer ring control deviation, the middle ring control deviation and the inner ring control deviation according to the outer ring shaft angle data, the middle ring shaft angle data and the inner ring shaft angle data, and generates an outer ring servo control pulse, a middle ring servo control pulse and an inner ring servo control pulse. The inner ring servo control pulse is used to synchronize the inner ring drive unit. At the same time, the inner ring drive unit receives the inner ring control deviation EZ output by the control unit to complete the control of the inner ring shaft. The middle ring servo control pulse is used to synchronize the middle ring drive unit. At the same time, the middle ring drive unit receives the middle ring control deviation output by the control unit to complete the control of the middle ring shaft. The outer ring servo control pulse is used to synchronize the outer ring drive unit. At the same time, the outer ring driver receives the outer ring control deviation output by the control unit to complete the control of the outer ring shaft. The control unit includes an FPGA processor and a DSP processor, and the FPGA processor and the DSP processor are electrically connected via an SRIO interface. The FPGA processor implements logic and interface functions as well as programmable fixed computing functions, and the DSP processor implements the control functions of the speed loop and position loop of the turntable. The FPGA processor generates internal synchronization pulses, shaft angle data latch pulses for control, and shaft angle data latch pulses for synchronization recording; The control unit also includes a data output interface, a remote control interface and an external synchronization pulse input interface. The data output interface is an RS422 serial interface, which is used to send three-axis angle synchronization data latched by synchronization pulses to the user device. The remote control interface is used to receive remote control instructions sent by the user remotely to realize the remote control function of the turntable. The external synchronization pulse input interface is used to receive the synchronization signal sent by the user to the turntable controller.

2. A high-precision equal-step-size control device according to claim 1, characterized in that: The inverter U2A, inverter U2B, inverter U2C, inverter U2D, inverter U2E and inverter U2F are all SN74LS04D.

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