Two-dimensional direct drive control system and control method

Abstract

The application discloses a two-dimensional direct drive control system and a control method, which comprises a controller, a motor driver, a direct drive motor, a rotary transformer and the like; a multipole rotary transformer is adopted as a position detection sensor, and the fine pole signal of the existing multipole rotary transformer is used to provide the motor driver for high-precision speed detection, so that a new speed sensor is not arranged. The application divides position control into a conventional control mode and a low-speed mode, fully utilizes the advantages of the two controls, and makes the mode two only run in the control at low speed. Since the speed sensor has long change time and large speed disturbance in low-speed measurement, the system response is slow and difficult to stabilize, so that the position control is reasonably selected under the mode two, the system control no longer comprises a speed loop, and the low-speed performance of the system can be effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of turntable drive control technology, specifically relating to a high-precision direct drive turntable control system and control method. Background Technology

[0002] Direct drive technology simplifies mechanical transmission devices such as gearboxes and lead screws, eliminates backlash in the transmission chain, and improves the rigidity of the transmission chain, providing more possibilities for improving control performance. At the same time, direct drive technology improves efficiency and reduces noise. With the increase in the output torque of direct drive motors, the use of direct drive technology to realize high-precision turntables has extremely significant application value.

[0003] Because direct drive systems lack a speed reduction device, conventional control methods struggle to balance high-speed and low-speed control performance when a wide speed range is required. This is especially true at low speeds, where the long speed feedback detection time significantly impacts the system's low-speed performance. Existing speed sensors not only exhibit long change times and large speed disturbances in low-speed measurements, resulting in slow system response and instability, but also contribute to the problem of instability. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a two-dimensional direct-drive control system and method. It utilizes a rotary transformer at the same position to provide signals to both the controller and the motor driver. The precise signal from the rotary transformer is provided to the motor driver, improving speed measurement accuracy. Simultaneously, it divides position control into different modes, thereby improving position control performance.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A two-dimensional direct drive control system, characterized in that it comprises: a controller, a motor driver 1, a direct drive motor 1, a rotary transformer 1, a motor driver 2, a direct drive motor 2, and a rotary transformer 2. The controller is used to implement position control of direct drive motor one and direct drive motor two; The motor driver is used to control the current and speed of the direct drive motor, which drives the shaft of the two-dimensional direct drive system. A rotary transformer is installed on the direct drive motor for position detection. The second motor driver is used to control the current and speed of the second direct drive motor, which drives the second shaft of the two-dimensional direct drive system. A second rotary transformer is installed on the second direct drive motor for position detection.

[0007] To optimize the above technical solution, the specific measures also include: Furthermore, both the first and second rotary transformers are multi-pole rotary transformers, and the output signal of the multi-pole rotary transformer includes a fine pole signal and a coarse pole signal; The fine and coarse pole signals output by the rotary transformer are sent to the controller for position detection of the direct drive motor; at the same time, the fine pole signal output by the rotary transformer is also sent to the motor driver for speed detection of the direct drive motor. The fine and coarse pole signals output by the rotary transformer 2 are sent to the controller for position detection of the direct drive motor 2; at the same time, the fine pole signal output by the rotary transformer 2 is also sent to the motor driver 2 for speed detection of the direct drive motor 2 by the motor driver 2.

[0008] Furthermore, the roughing-to-finishing ratio of the multi-pole rotary transformer is 1:16.

[0009] Furthermore, the controller includes a position controller, a mode control module, a calculation circuit, a position controller, a mode control module, and a calculation circuit. The mode control module one is used to change the control mode of the direct drive motor one, which includes two modes: speed control and current control. The calculation circuit two is used to calculate the fine pole signal and coarse pole signal of the rotary transformer one, generate the actual position digital signal of the direct drive motor one, and provide it as a position feedback value to the position controller one. The position controller one receives the position setpoint and the position feedback value of the calculation circuit two, and outputs the speed setpoint to the direct drive motor one in speed control mode and outputs the current setpoint to the direct drive motor one in current control mode. The mode control module 2 is used to change the control mode of the direct drive motor 2, which includes two modes: speed control and current control. The calculation circuit 4 is used to calculate the fine pole signal and coarse pole signal of the rotary transformer 2, generate the actual position digital signal of the direct drive motor 2, and provide it as a position feedback value to the position controller 2. The position controller 2 receives the position setpoint and the position feedback value from the calculation circuit 4, and outputs the speed setpoint to the direct drive motor 2 in speed control mode and outputs the current setpoint to the direct drive motor 2 in current control mode.

[0010] Furthermore, both position controller one and position controller two are equipped with saturation characteristic modules at their output terminals to limit the extreme values ​​of the output.

[0011] Furthermore, the motor driver includes a speed controller, a current control module, a calculation circuit, and a speed calculation module. In speed control mode, the calculation circuit calculates the precise pole signal of the rotary transformer to obtain the precise pole position signal of the direct drive motor. The precise pole position signal is then calculated by the speed calculation module to obtain the actual speed of the direct drive motor. The speed controller simultaneously receives the speed setpoint from the position controller and the actual speed from the speed calculation module. After completing the speed correction of the direct drive motor, the speed is transmitted to the current control module for control of the direct drive motor. In current control mode, the current control module receives the current setpoint from the position controller and controls the direct drive motor. The motor driver 2 includes a speed controller 2, a current control module 2, a calculation circuit 3, and a speed calculation module 2. In speed control mode, the calculation circuit 3 calculates the precise pole signal of the rotary transformer 2 to obtain the precise pole position signal of the direct drive motor 2. The precise pole position signal is then calculated by the speed calculation module 2 to obtain the actual speed of the direct drive motor 2. The speed controller 2 simultaneously receives the speed setpoint from the position controller 2 and the actual speed from the speed calculation module 2. After completing the speed correction of the direct drive motor 2, the speed is transmitted to the current control module 2 to control the direct drive motor 2. In current control mode, the current control module 2 receives the current setpoint from the position controller 2 to control the direct drive motor 2.

[0012] Furthermore, both the input terminals of the current control module one and the current control module two are equipped with selection switches.

[0013] Furthermore, both the speed controller one and the speed controller two are equipped with a saturation characteristic module at their output terminals to limit the extreme values ​​of the output.

[0014] This invention also proposes a control method for the aforementioned two-dimensional direct drive control system, characterized in that: when selecting the speed control mode, the control process for shaft one and shaft two is as follows: Step 1: Set the operating mode of motor driver 1 to speed control mode in mode control module 1; set the operating mode of motor driver 2 to speed control mode in mode control module 2. Step 2: Position controller 1 receives the position setpoint and the position feedback value from calculation circuit 2, calculates the difference and performs position correction, using proportional-integral control; Position controller 2 receives the position setpoint and the position feedback value from calculation circuit 4, calculates the difference and performs position correction, using proportional-integral control. Step 3: The output of position controller one passes through the saturation characteristic module and is then transmitted as the speed setpoint to the speed controller one of motor driver one via the fieldbus, completing the control of direct drive motor one; the output of position controller two passes through the saturation characteristic module and is then transmitted as the speed setpoint to the speed controller two of motor driver two via the fieldbus, completing the control of direct drive motor two.

[0015] This invention also proposes a control method for the aforementioned two-dimensional direct drive control system, characterized in that: when selecting the current control mode, the control processes for shaft one and shaft two are as follows: Step 1: Set the operating mode of motor driver 1 to current control mode in mode control module 1; set the operating mode of motor driver 2 to current control mode in mode control module 2. Step 2: Position controller 1 receives the position setpoint and the position feedback value from the calculation circuit 2, calculates the difference and performs position correction, using lead-lag control; Position controller 2 receives the position setpoint and the position feedback value from the calculation circuit 4, calculates the difference and performs position correction, using lead-lag control. Step 3: The output of position controller one passes through the saturation characteristic module and is then transmitted as the current setpoint to the current control module one of motor driver one via the fieldbus to complete the control of the direct drive motor one; the output of position controller two passes through the saturation characteristic module and is then transmitted as the current setpoint to the current control module two of motor driver two via the fieldbus to complete the control of the direct drive motor two.

[0016] The beneficial effects of this invention are: 1) A multi-pole rotary transformer is used as a position detection sensor. At the same time, the fine pole signal of the existing multi-pole rotary transformer is used to provide the motor driver with high-precision speed detection, and no new speed sensor is set up. 2) Two control modes were designed. Mode 1 adopts the conventional position control method, which includes a speed control loop. This method has the advantages of maximum speed of motor drive system and strong anti-disturbance capability. Mode 2 does not include speed control and is only used for control at low speed. By reasonably selecting position control, the system control no longer includes a speed loop, which can effectively improve the low-speed performance of the system. Attached Figure Description

[0017] Figure 1 This is a structural diagram of a two-dimensional direct drive control system according to the present invention.

[0018] Figure 2 This diagram illustrates the connection method of the rotary transformer in a two-dimensional direct drive control system according to the present invention.

[0019] Figure 3 This is a schematic diagram of the control method for the controller controlling axis one of the present invention.

[0020] Figure 4 This is a simplified system model diagram of the position control mode one of the present invention.

[0021] Figure 5 This is a simplified system model diagram of the second position control mode of the present invention. Detailed Implementation

[0022] The invention will now be described in further detail with reference to the accompanying drawings.

[0023] like Figure 1 As shown, a two-dimensional direct drive control system is characterized by comprising a controller, a first motor driver, a first direct drive motor, a first rotary transformer, a second motor driver, a second direct drive motor, and a second rotary transformer. The controller performs position control of the direct drive system and exchanges information with the first and second motor drivers via a fieldbus. The first motor driver performs current and speed control of the first direct drive motor, which drives axis one of the two-dimensional direct drive system. A first rotary transformer is installed on the first direct drive motor to detect its position information. The second motor driver performs current and speed control of the second direct drive motor. A second rotary transformer is installed on the second direct drive motor to detect its position information, and the second direct drive motor drives axis two of the two-dimensional direct drive system.

[0024] like Figure 2 As shown, rotary transformer one is a multi-pole rotary transformer. In this embodiment, the coarse-to-fine ratio is 1:16. The output signal of the multi-pole rotary transformer includes a fine pole signal and a coarse pole signal. The fine pole signal and coarse pole signal of rotary transformer one are connected to the controller for high-precision position detection of motor one directly. The fine pole signal of rotary transformer one is multiplexed, that is, it is simultaneously connected to motor driver one for speed detection of motor driver one directly driving motor one. Rotary transformer two is also a multi-pole rotary transformer, and the connection method is the same as that of rotary transformer one.

[0025] Figure 3 The control method for axis one is illustrated. The controller includes modules such as position controller one, mode control module one, saturation characteristic module one, saturation characteristic module two, and calculation circuit two. Calculation circuit two calculates the fine and coarse pole signals of the rotary transformer one, generating the actual digital signal of the direct drive motor one's position, which is provided to position controller one as a feedback signal. Mode control module one is used to change the control method of the direct drive motor one. The controller's control method for axis two is exactly the same as that for axis one; the specific control method will be explained below using the control of axis one as an example.

[0026] The mode control module one divides the direct drive motor one into two control modes: Mode 1 and Mode 2. The specific process of Mode 1 control is as follows: Step 1: Set the operating mode of motor driver 1 in mode control module 1 to speed control mode; Step 2: Position controller 1 receives the position setpoint and the position feedback value from calculation circuit 2, calculates the difference, and performs position correction using conventional proportional-integral control; Step 3: The output of position controller 1 is transmitted through saturation characteristic module 1 and fieldbus to speed controller 1 of motor driver 1 as speed setpoint to complete the position control of direct drive motor 1.

[0027] The specific process of mode 2 control is as follows: Step 1: Set the operating mode of motor driver 1 in mode control module 1 to current control mode; Step 2: Position controller 1 receives the position setpoint and the position feedback value from calculation circuit 2, calculates the difference, performs position correction, and adopts lead-lag control; Step 3: The output of position controller 1 is transmitted through saturation characteristic module 2 and fieldbus to current control module 1 of motor driver 1 as current setpoint to complete the control of direct drive motor 1.

[0028] Among them, saturation characteristic module one is used to limit the extreme value of the position controller output, that is, not exceeding the rated speed value of the motor; saturation characteristic module two is used to limit the extreme value of the position controller output, that is, not exceeding the rated current value of the motor.

[0029] The control methods described above, Mode 1 and Mode 2, are used for high-speed control and Mode 2 for low-speed control. The switching speed between high and low speeds is determined by the measurement accuracy of the speed sensor, or it can be determined by actual system debugging.

[0030] See also Figure 3 The motor driver includes a speed controller, a saturation characteristic module, a selector switch, a current control module, a calculation circuit, and a speed calculation module. Both speed and current control utilize conventional control methods for the direct drive motor. The calculation circuit calculates the precise pole signal of the rotary transformer to obtain the position signal detected by the precise pole. This precise pole position signal is then processed by the speed calculation module to obtain the actual speed of the direct drive motor. The speed controller receives the speed setpoint from the position controller via a fieldbus and simultaneously receives the actual speed calculated by the speed calculation module. After speed correction of the direct drive motor, the signal is transmitted through the saturation characteristic module to the current control module, completing the control of the direct drive motor.

[0031] Among them, saturation characteristic module three is used to limit the extreme values ​​of the speed controller output, and the method of value selection is the same as that of saturation characteristic module two. The structure and connection method of motor driver two are exactly the same as those of motor driver one.

[0032] Figure 4 This is a simplified structural diagram of the control system in Mode 1, which includes system model 1 and position regulator 1. Kv is the speed gain of the simplified system model, and Tv is the simplified speed time constant. Based on this model, this example selects a proportional-integral regulator as the position regulator.

[0033] Figure 5 This is a simplified structural diagram of the Mode 2 control system, which includes System Model 2 and Position Regulator 2. Kc is the current gain of the simplified system model, and Tc is the simplified current time constant. Based on this model, there are two integral elements, so proportional or proportional-integral regulation cannot be used, otherwise the system will be unstable. In this example, the position regulator is selected as a lead-lag regulator.

[0034] It should be noted that the terms such as "upper", "lower", "left", "right", "front", and "back" used in the invention are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0035] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A two-dimensional direct-drive control system, characterized in that, include: Controller, motor driver 1, direct drive motor 1, rotary transformer 1, motor driver 2, direct drive motor 2, and rotary transformer 2; The controller is used to implement position control of direct drive motor one and direct drive motor two; The motor driver is used to control the current and speed of the direct drive motor, which drives the shaft of the two-dimensional direct drive system. A rotary transformer is installed on the direct drive motor for position detection. The second motor driver is used to control the current and speed of the second direct drive motor, which drives the second shaft of the two-dimensional direct drive system. A second rotary transformer is installed on the second direct drive motor for position detection. Both rotary transformer one and rotary transformer two are multi-pole rotary transformers, and the output signal of the multi-pole rotary transformer includes fine pole signal and coarse pole signal; The fine and coarse pole signals output by the rotary transformer are sent to the controller for position detection of the direct drive motor; at the same time, the fine pole signal output by the rotary transformer is also sent to the motor driver for speed detection of the direct drive motor. The fine and coarse pole signals output by the rotary transformer 2 are sent to the controller for position detection of the direct drive motor 2; at the same time, the fine pole signal output by the rotary transformer 2 is also sent to the motor driver 2 for speed detection of the direct drive motor 2 by the motor driver 2. The controller includes a position controller, a mode control module, a calculation circuit, and a calculation circuit. The mode control module one is used to change the control mode of the direct drive motor one, which includes two modes: speed control and current control. The calculation circuit two is used to calculate the fine pole signal and coarse pole signal of the rotary transformer one, generate the actual position digital signal of the direct drive motor one, and provide it as a position feedback value to the position controller one. The position controller one receives the position setpoint and the position feedback value of the calculation circuit two, and outputs the speed setpoint to the direct drive motor one in speed control mode and outputs the current setpoint to the direct drive motor one in current control mode. The mode control module 2 is used to change the control mode of the direct drive motor 2, which includes two modes: speed control and current control. The calculation circuit 4 is used to calculate the fine pole signal and coarse pole signal of the rotary transformer 2, generate the actual position digital signal of the direct drive motor 2, and provide it as a position feedback value to the position controller 2. The position controller 2 receives the position setpoint and the position feedback value from the calculation circuit 4, and outputs the speed setpoint to the direct drive motor 2 in speed control mode and outputs the current setpoint to the direct drive motor 2 in current control mode.

2. The two-dimensional direct drive control system as described in claim 1, characterized in that: The roughing-to-finishing ratio of the multi-pole rotary transformer is 1:

16.

3. The two-dimensional direct drive control system as described in claim 1, characterized in that: Both position controller one and position controller two have a saturation characteristic module at their output terminals to limit the extreme values ​​of the output.

4. A two-dimensional direct drive control system as described in claim 1, characterized in that: The motor driver includes a speed controller, a current control module, a calculation circuit, and a speed calculation module. In speed control mode, the calculation circuit calculates the precise pole signal of the rotary transformer to obtain the precise pole position signal of the direct drive motor. The precise pole position signal is then calculated by the speed calculation module to obtain the actual speed of the direct drive motor. The speed controller simultaneously receives the speed setpoint from the position controller and the actual speed from the speed calculation module. After completing the speed correction of the direct drive motor, the speed is transmitted to the current control module for control of the direct drive motor. In current control mode, the current control module receives the current setpoint from the position controller and controls the direct drive motor. The motor driver 2 includes a speed controller 2, a current control module 2, a calculation circuit 3, and a speed calculation module 2. In speed control mode, the calculation circuit 3 calculates the precise pole signal of the rotary transformer 2 to obtain the precise pole position signal of the direct drive motor 2. The precise pole position signal is then calculated by the speed calculation module 2 to obtain the actual speed of the direct drive motor 2. The speed controller 2 simultaneously receives the speed setpoint from the position controller 2 and the actual speed from the speed calculation module 2. After completing the speed correction of the direct drive motor 2, the speed is transmitted to the current control module 2 to control the direct drive motor 2. In current control mode, the current control module 2 receives the current setpoint from the position controller 2 to control the direct drive motor 2.

5. A two-dimensional direct drive control system as described in claim 4, characterized in that: Both the input terminals of current control module one and current control module two are equipped with selection switches.

6. A two-dimensional direct drive control system as described in claim 4, characterized in that: Both speed controller one and speed controller two have a saturation characteristic module at their output terminals to limit the extreme values ​​of the output.

7. A control method for a two-dimensional direct drive control system as described in claim 4, characterized in that: When selecting the speed control mode, the control process for shaft one and shaft two is as follows: Step 1: Set the operating mode of motor driver 1 to speed control mode in mode control module 1; set the operating mode of motor driver 2 to speed control mode in mode control module 2. Step 2: Position controller 1 receives the position setpoint and the position feedback value from calculation circuit 2, calculates the difference and performs position correction, using proportional-integral control; Position controller 2 receives the position setpoint and the position feedback value from calculation circuit 4, calculates the difference and performs position correction, using proportional-integral control. Step 3: The output of position controller one passes through the saturation characteristic module and is then transmitted as the speed setpoint to the speed controller one of motor driver one via the fieldbus, completing the control of direct drive motor one; the output of position controller two passes through the saturation characteristic module and is then transmitted as the speed setpoint to the speed controller two of motor driver two via the fieldbus, completing the control of direct drive motor two.

8. A control method for a two-dimensional direct drive control system as described in claim 4, characterized in that: When selecting the current control mode, the control process for shaft one and shaft two is as follows: Step 1: Set the operating mode of motor driver 1 to current control mode in mode control module 1; set the operating mode of motor driver 2 to current control mode in mode control module 2. Step 2: Position controller 1 receives the position setpoint and the position feedback value from the calculation circuit 2, calculates the difference and performs position correction, using lead-lag control; Position controller 2 receives the position setpoint and the position feedback value from the calculation circuit 4, calculates the difference and performs position correction, using lead-lag control. Step 3: The output of position controller one passes through the saturation characteristic module and is then transmitted as the current setpoint to the current control module one of motor driver one via the fieldbus to complete the control of the direct drive motor one; the output of position controller two passes through the saturation characteristic module and is then transmitted as the current setpoint to the current control module two of motor driver two via the fieldbus to complete the control of the direct drive motor two.

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