Motor switching device and method for a motion stage

Abstract

The application discloses a motor switching device and method of a motion table, and the device comprises the motion table, a first motor, a second motor, a switching module, a driver and a main controller. The output end of the first motor is connected with the motion table, and the first motor is used for controlling the motion of the motion table at a first precision. The output end of the second motor is connected with the motion table, and the second motor is used for controlling the motion of the motion table at a second precision. The first precision is smaller than the second precision. The output end of the switching module is connected with the input end of the first motor and the input end of the second motor respectively. The output end of the driver is connected with the input end of the switching module. The input end of the driver and the control end of the switching module are connected with the main controller respectively, and the main controller is used for controlling the switching module to switch on the first motor and the second motor. Thus, only one driver and two motors are arranged, and the motion control of the motion table at different precisions can be realized.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor testing technology, and in particular to a motor switching device and method for a motion table. Background Technology

[0002] With the continuous development of IC products, the processing of workpieces in the semiconductor industry has become particularly important. A common requirement for workpiece processing is to bring the upper surface of the workpiece into a certain depth of focus and maintain the upper surface within that depth of focus during processing. As the semiconductor industry has developed, the precision of depth of focus control has decreased from the hundreds of micrometers level to the micrometer level, and even to the nanometer level. Simultaneously, the requirements for the speed, acceleration, and positional accuracy of the workpiece during processing are becoming increasingly stringent. Furthermore, the higher the precision requirements of the processed object, the higher the precision requirements for trajectory tracking during processing. Additionally, the size of the workpiece itself is also increasing, leading to higher demands on the motor output during the acceleration phase.

[0003] Currently, control typically employs two sets of motors and two sets of power amplifiers (PAs). One set consists of a high-output, long-stroke coarse motor and PA to meet the high acceleration requirements of the workpiece machining table during formation and movement. The other set consists of a low-output, short-stroke fine motor and PA to meet the tracking accuracy requirements during uniform motion. The drawback of this method is that as market demands decrease in depth of focus, increase in control precision, and process larger workpieces, the motion control system becomes increasingly complex, ultimately making it difficult to implement a synchronous motion control system. Furthermore, the repeated use of multiple sets of motors and PAs also increases costs. Summary of the Invention

[0004] This invention provides a motor switching device and method for a motion table. By using a driver and two motors, the first motor and the second motor can be switched stably, avoiding motion table fluctuations and improving the control accuracy of the motion table.

[0005] To achieve the above objectives, one embodiment of the present invention provides a motor switching device for a motion table, comprising:

[0006] Sports table;

[0007] A first motor, the output end of which is connected to the motion table, is used to control the motion table to move at a first precision.

[0008] A second motor, the output of which is connected to the motion table, is used to control the motion table to move at a second precision; wherein the first precision is less than the second precision.

[0009] A switching module, the output of which is connected to the input of the first motor and the input of the second motor, respectively;

[0010] A driver, the output of which is connected to the input of the switching module;

[0011] The main controller is connected to the input terminal of the driver and the control terminal of the switching module. The main controller is used to control the switching module to switch between the first motor and the second motor.

[0012] According to one embodiment of the present invention, the main controller is further configured to control the output voltage of the driver and send a switching command to the switching module, wherein the switching module is configured to switch the first motor and the second motor on according to the output voltage of the driver and the switching command.

[0013] According to one embodiment of the present invention, the switching module includes: an energy storage unit and a switching switch, wherein the input terminal of the energy storage unit is connected to the driver, one end of the switching switch is connected to the output terminal of the energy storage unit, and the other end of the switching switch is connected to the first motor or the second motor;

[0014] The energy storage unit includes an energy storage circuit and a first switch.

[0015] According to one embodiment of the present invention, the energy storage circuit is further connected to the main controller, which calculates the torque of one of the first motor and the second motor based on the current of the energy storage circuit, estimates the torque of the other motor based on the voltage of the energy storage circuit, and controls the switching switch to operate based on the torque of the first motor and the torque of the second motor.

[0016] According to one embodiment of the present invention, the device further includes: a measurement unit connected to the main controller, for measuring the displacement information of the motion table and sending a displacement measurement signal to the main controller, wherein the main controller is used to send a switching command to the switching module based on the displacement measurement signal and control the output voltage of the driver.

[0017] According to one embodiment of the present invention, the measuring unit includes a plurality of laser rulers, each of which is arranged around the motion table.

[0018] To achieve the above objectives, another embodiment of the present invention provides a motor switching method for a motion table, implemented based on the motor switching device for the motion table as described above. The method includes the following steps:

[0019] The main controller sends voltage control commands to the driver and switching commands to the switching module;

[0020] The driver adjusts its output voltage according to the voltage control command;

[0021] When the switching module receives the switching command, it switches between the first motor and the second motor according to the output voltage of the driver.

[0022] According to one embodiment of the present invention, the switching module includes: an energy storage unit and a switching switch, wherein the input terminal of the energy storage unit is connected to the driver, one end of the switching switch is connected to the output terminal of the energy storage unit, and the other end of the switching switch is connected to the first motor or the second motor; the energy storage unit includes an energy storage circuit and a first switch;

[0023] When the switching module receives the switching command, it switches the first motor and the second motor on according to the output voltage of the driver, including:

[0024] When the switching module receives the switching command, it controls the energy storage circuit to store energy, and disconnects the first switch when the energy storage value of the energy storage circuit reaches the target energy storage value.

[0025] Control the operation of the switching switch;

[0026] When the output voltage of the driver reaches the target output voltage, the first switch is closed.

[0027] According to one embodiment of the present invention, the energy storage circuit is connected to the main controller;

[0028] Before controlling the operation of the switching switch, the following is also included:

[0029] The main controller calculates the torque of one of the first motors and the second motor based on the current of the energy storage circuit, and estimates the torque of the other motor based on the voltage of the energy storage circuit. When the difference between the torque of the first motor and the torque of the second motor is within a first preset range, the controller controls the switching switch to operate.

[0030] According to one embodiment of the present invention, the motor switching device of the motion table further includes: a measurement unit connected to the main controller, used to measure the displacement information of the motion table and send a displacement measurement signal to the main controller;

[0031] Before the main controller sends voltage control commands to the driver and switching commands to the switching module, the process includes:

[0032] The main controller receives the displacement measurement signal;

[0033] When the displacement measurement signal is within the second preset value range, the main controller sends a voltage control command to the driver and a switching command to the switching module.

[0034] According to an embodiment of the present invention, a motor switching device and method for a motion table are provided. The motor switching device includes: a motion table; a first motor, a second motor, a switching module, a driver, and a main controller. The output terminal of the first motor is connected to the motion table, and the first motor controls the motion table to move at a first precision. The output terminal of the second motor is connected to the motion table, and the second motor controls the motion table to move at a second precision. The first precision is less than the second precision. The output terminal of the switching module is connected to the input terminals of the first motor and the second motor, respectively. The output terminal of the driver is connected to the input terminal of the switching module. The main controller is connected to the input terminal of the driver and the control terminal of the switching module, respectively, and the main controller controls the switching module to switch between the first motor and the second motor. Therefore, by using this motor switching device for the motion table, only one driver and two motors are needed to achieve motion control of the motion table at different precisions. This not only ensures the precision of the motion control but also reduces product cost and integration difficulty, thereby enhancing product competitiveness. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the motor switching device for the motion table proposed in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the switching module in the motor switching device of the motion table proposed in an embodiment of the present invention;

[0037] Figure 3 This is a flowchart of the motor switching method for the motion table proposed in an embodiment of the present invention;

[0038] Figure 4 This is a flowchart of a motor switching method for a motion table according to an embodiment of the present invention;

[0039] Figure 5 This is a flowchart of a motor switching method for a motion table according to another embodiment of the present invention;

[0040] Figure 6 This is a flowchart of a motor switching method for a motion table according to another embodiment of the present invention;

[0041] Figure 7 This is a flowchart of a motor switching method for a motion table proposed in another embodiment of the present invention. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0043] Traditional motion control systems currently employ two sets of motors and a power amplifier (PA), resulting in a complex structure and increased costs due to the reuse of two sets of motors. Therefore, this invention provides a motor switching device and method for a motion table. This method ensures precise motion control, meets market demands, and enables switching between coarse and fine motion at different motion stages. This reduces costs, simplifies overall system integration, significantly enhances product competitiveness, and helps win customer favor in the market.

[0044] To facilitate understanding of this embodiment, a motor switching device for a motion table disclosed in this embodiment of the invention will first be described in detail.

[0045] This invention provides a motor switching device for a motion table, which is mainly applied in the field of workpiece processing, especially in the technical field where high-precision motion control is required during processing. Figure 1 This is a schematic diagram of the motor switching device for the motion table proposed in an embodiment of the present invention. Figure 1 As shown, the motor switching device 100 of the motion table includes: motion table 101, first motor 102, second motor 103, switching module 104, driver 105, and main controller 106.

[0046] The output of the first motor 102 is connected to the motion table 101, and the first motor 102 is used to control the motion table 101 to move at a first precision. The output of the second motor 103 is connected to the motion table 101, and the second motor 103 is used to control the motion table 101 to move at a second precision. The first precision is less than the second precision. The output of the switching module 104 is connected to the input of the first motor 102 and the input of the second motor 103. The output of the driver 105 is connected to the input of the switching module 104. The main controller 106 is connected to the input of the driver 105 and the control terminal of the switching module 104, and the main controller 106 is used to control the switching module 104 to switch the first motor 102 and the second motor 103 on and off.

[0047] It should be noted that the first motor 102 can be referred to as the coarse motor, and the second motor 103 can be referred to as the fine motor. The operating voltage of the first motor 102 is greater than that of the second motor 103. Specifically, the first motor 102 operates in a high-torque, low-precision state, such as when the motion table 101 is unstable at startup. In this case, the control precision requirement is relatively low, and the driver 105 can drive the first motor 102 to control the motion table 101. Conversely, the second motor 103 operates in a low-torque, high-precision state, such as when the motion table 101 moves at a constant speed, where the control precision requirement is higher. In this case, the driver 105 can drive the second motor 103 to control the motion table 101.

[0048] The first motor 102 and the second motor 103 drive the motion table 101, respectively. The motion table 101 moves along a predetermined trajectory. Optionally, both the first motor 102 and the second motor 103 can be servo motors. The main controller 106 can determine the current driving force using a corresponding control algorithm and control the output voltage of the driver 105. The driver 105 can drive either the first motor 102 or the second motor 103 according to different output voltages to drive the motion table 101.

[0049] According to one embodiment of the present invention, the main controller 106 is further configured to control the output voltage of the driver 105 and send a switching command to the switching module 104. The switching module 104 is configured to switch between connecting the first motor 102 and the second motor 103 based on the output voltage of the driver 105 and the switching command. That is, the switching module 106 determines whether the switching module 104 connects to the first motor 102 or the second motor 103 based on the magnitude of the output voltage of the driver 105 and the switching signal sent by the main controller 106.

[0050] Understandably, the main controller 106 can control the output voltage of the driver 105 by adjusting the duty cycle of SVPWM (Space Vector Pulse Width Modulation); the switching command can be a digital signal, for example, 0 indicates switching from the first motor 102 to the second motor 103, and 1 indicates switching from the second motor 103 to the second motor 102.

[0051] Based on this, the motor switching device for the motion table proposed in this embodiment of the invention only requires one driver and two motors to achieve motion control of the motion table at different precision levels. This not only ensures the precision of motion control of the motion table, but also reduces product cost and integration difficulty, thereby enhancing product competitiveness.

[0052] According to one embodiment of the present invention, such as Figure 2As shown, the switching module 104 includes: an energy storage unit 1041 and a switching switch 1042. The input terminal of the energy storage unit 1041 is connected to the driver 105. One end of the switching switch 1042 is connected to the output terminal of the energy storage unit 1041. The other end of the switching switch 1042 is connected to the first motor 102 or to the second motor 103.

[0053] The energy storage unit 1041 includes an energy storage circuit 10411 and a first switch 10412. The energy storage circuit 10411 can be an energy storage capacitor, and the switching switch 1042 can be a solenoid valve. The energy storage circuit 10411 and the first switch 10412 are connected in parallel, and the first switch 10412 can be an electronic switch. The motor switching device of this motion table uses three-phase AC power.

[0054] For example, when the switching module 104 is connected to the first motor 102, the first switch 10412 is closed, and the switching switch 1042 is connected to the first motor 102. When the motion table 101 requires control of the second motor 103 with higher precision (e.g., in workpiece inspection), the main controller 106 sends a switching command to the switching module 104. After receiving the switching command, the switching module 104 controls the energy storage circuit 10411 to store energy, and when the energy storage value of the energy storage circuit 10411 reaches the target energy storage value, it controls the first switch 10412 to open. At the same time, the main controller 106 sends a voltage control command to the driver 105 to change the output voltage of the driver 105 from matching the first motor 102 to matching the second motor 103. When the output voltage of the driver 105 matches the second motor 103, the switching switch 1042 is disconnected from the first motor 102 and connected to the second motor 103. Simultaneously, the first switch 10412 is closed. The switching module 104 is switched from being connected to the first motor 102 to being connected to the second motor 103, so as to achieve seamless switching between the first motor 102 and the second motor 103.

[0055] Similarly, when the switching module 104 is connected to the second motor 103, the first switch 10412 is closed, and the switching switch 1042 is connected to the second motor 103. When the motion table 101 requires control of the second motor 102 with lower precision (e.g., after workpiece inspection), the main controller 106 sends a switching command to the switching module 104. Upon receiving the switching command, the switching module 104 controls the energy storage circuit 10411 to store energy, and when the energy storage value of the energy storage circuit 10411 reaches the target energy storage value, it controls the first switch 10412 to open. Simultaneously, the main controller 106 sends a voltage control command to the driver 105, causing the output voltage of the driver 105 to switch from matching the second motor 103 to matching the first motor 102. When the output voltage of the driver 105 matches the first motor 102, the switching switch 1042 is disconnected from the second motor 103, and the switching switch 1042 is connected to the first motor 102. At the same time, the first switch 10412 is closed. The switching module 104 is switched from being connected to the second motor 103 to being connected to the first motor 102. This allows for seamless switching between the first motor 102 and the second motor 103.

[0056] It should be noted that the switching switch 1042 in the switching module 104 can be activated at any time between opening and closing the first switch 10412.

[0057] Taking the switching from the first motor 102 to the second motor 103 as an example, during the energy storage process of the energy storage circuit 10411, the output voltage of the driver 105 is already changing from the working voltage of the first motor 102 to the working voltage of the second motor 103, that is, from high voltage to low voltage. This process can slow down the speed of the first motor 102. When the energy storage value of the energy storage circuit 10411 reaches the target energy storage value, the first switch 10412 is opened, and the switching switch 1042 can be controlled to operate at the same time. The energy storage circuit 10411 can pre-start the second motor 103. When the output voltage of the driver 105 reaches the working voltage of the second motor 103, the first switch 10412 is closed, and the second motor 103 works normally.

[0058] Taking the switching from the second motor 103 to the first motor 102 as an example, during the energy storage process of the energy storage circuit 10411, the output voltage of the driver 105 is already changing from the operating voltage of the second motor 103 to the operating voltage of the second motor 102, that is, from low voltage to high voltage. This process causes the speed of the second motor 102 to increase. When the energy storage value of the energy storage circuit 10411 reaches the target energy storage value, the first switch 10412 is immediately disconnected. After a period of time (during which the energy storage circuit 10411 can cause the second motor 103 to slowly stop), the switching switch 1042 is then controlled to operate. The energy storage circuit 10411 can first pre-start the first motor 102. When the output voltage of the driver 105 reaches the operating voltage of the first motor 102, the first switch 10412 is closed, and the first motor 102 operates normally. The target energy storage value needs to meet the energy consumption of the first motor 102 and the second motor 103 during the switching process.

[0059] This allows for seamless switching between the first motor 102 and the second motor 103, preventing the motion table 101 from shaking during the switching process.

[0060] The following details when the switch 1042 will take action.

[0061] According to one embodiment of the present invention, the energy storage circuit 10411 is also connected to the main controller 106. The main controller 106 calculates the torque of one of the first motor 102 and the second motor 103 based on the current of the energy storage circuit 10411, estimates the torque of the other motor based on the voltage of the energy storage circuit 10411, and controls the switching switch 1042 to operate based on the magnitude of the torque of the first motor 102 and the torque of the second motor 103.

[0062] The torque difference between the two motors can be calculated using the current in the energy storage circuit 10411. When the switching module 104 is connected to the first motor 102, the torque of the first motor 102 is calculated using the current in the energy storage circuit 10411, and the torque of the second motor 103 is estimated using the voltage in the energy storage circuit 10411. When the switching module 104 is connected to the second motor 103, the torque of the second motor 103 is calculated using the current in the energy storage circuit 10411, and the torque of the first motor 102 is estimated using the voltage in the energy storage circuit 10411. Taking the switching from the first motor 102 to the second motor 103 as an example, specifically, given the three-phase AC voltages Ua, Ub, and Uc, this three-phase voltage is converted into a two-phase AC voltage U α U β The formula is:

[0063]

[0064] The two-phase AC voltage is converted into a two-phase DC voltage (Ud U is the voltage across the direct shaft of the motor. q The formula for the voltage across the q-axis of the motor (i.e., the voltage perpendicular to the rotor magnetic field direction) is:

[0065]

[0066] The above is based on the first constant R of the motor. d (The motor's d-axis resistance, i.e., the motor's direct axis resistance, is in the direction of the motor's rotor magnetic field.) The motor's d-axis current can then be calculated.

[0067] I d =U d / R d ,

[0068] Given the formula for the output power of the motor, and using the motor's second constant K... T (Motor torque coefficient) can be used to calculate the torque F:

[0069] F = K T *I d ,

[0070] Since the first and second constants are different for each motor, the difference in torque between the two motors can be calculated:

[0071] Δf=F1-F2

[0072] Because the switching time is shorter than the sampling period T S Generally, switching within 10 steps can be considered seamless. Therefore, the position error caused by torque fluctuation during the switching process can be obtained by dividing the torque fluctuation of the motion table 101 by the mass of the motion table 101 and performing a double integral over the theoretical maximum switching period.

[0073]

[0074] The mass m of the motion table 101 is 33 kg, and the sampling period T is... S Given a step size of 200µs, and a step size of 10, t is calculated to be 2000µs. The error window for entering uniform motion on the motion stage 101 is s, which, according to the specifications, is 100nm. Therefore, we can obtain...

[0075]

[0076] Furthermore, when the first switch 10412 is turned off, and when the torque difference between the first motor 102 and the second motor 103 is within 1.65N, the switching switch 1042 can be controlled to operate. At this time, the vibration of the first motor 102 and the second motor 103 on the motion table 101 will not exceed the difference between the actual motion trajectory of the motion table 101 and the preset motion trajectory. Thus, the vibration of the motion table 101 is within the error range and will not affect the workpiece measurement.

[0077] According to one embodiment of the present invention, such as Figure 1 As shown, the device 100 also includes: a measurement unit (161, 162) connected to the main controller 106, used to measure the displacement information of the motion table 101 and send the displacement measurement signal to the main controller 106. The main controller 106 is used to send a switching command to the switching module 104 based on the displacement measurement signal and control the output voltage of the driver 105.

[0078] It should be noted that the main controller 106 determines the current motion state of the motion table 101 based on the displacement measurement signal sent by the measurement unit, and decides whether the switching module 104 switches between the first motor 102 and the second motor 103. For example, when the motion table 101 carrying the workpiece moves from the start-up stage to the uniform motion stage of the trajectory planning, the main controller 106 issues a switching command based on the data returned by the measurement unit (i.e., the displacement information carried by the displacement measurement signal), and when the actual motion trajectory of the uniform motion stage differs from the preset motion trajectory within a preset range (less than 100nm), switching the first motor 102 driving the motion table 101 to the second motor 103 driving the motion table 101. Alternatively, when the motion table 101 carrying the workpiece finishes the uniform motion and enters the smooth stop stage, the main controller 106 issues a switching command based on the data returned by the measurement unit, switching the second motor 103 driving the motion table 101 to the first motor 102 driving the motion table 101. This embodiment of the invention mainly addresses the switching from the start-up stage to the uniform motion stage of the trajectory planning. This facilitates seamless switching between the first motor 102 and the second motor 103.

[0079] According to one embodiment of the present invention, the measuring unit includes a plurality of laser scales, each laser scale being arranged around the motion table 101. Figure 1 As shown, a first laser ruler 161 and a second laser ruler 162 are arranged around the motion table 101. Both the first laser ruler 161 and the second laser ruler 162 will feed the displacement measurement signal back to the main controller 106 in real time.

[0080] Figure 3 This is a flowchart of the motor switching method for a motion table according to an embodiment of the present invention. This method is implemented based on the aforementioned motor switching device for the motion table, as follows... Figure 3As shown, the method includes the following steps:

[0081] S101, the main controller 106 sends a voltage control command to the driver 105 and a switching command to the switching module 104;

[0082] According to one embodiment of the present invention, the motor switching device of the motion table further includes: a measurement unit connected to the main controller 106, used to measure the displacement information of the motion table 101 and send a displacement measurement signal to the main controller 106;

[0083] Before the S101 main controller 106 sends voltage control commands to the driver 105 and switching commands to the switching module 104, such as Figure 4 As shown, it includes:

[0084] S001, the main controller 106 receives the displacement measurement signal;

[0085] S002, when the displacement measurement signal is within the second preset value range, the main controller 106 sends a voltage control command to the driver 105 and a switching command to the switching module 104.

[0086] It is understandable that the displacement measurement signal being within the second preset value range means that when the motion table 101, carrying the workpiece, moves from the start-up stage to the uniform motion stage of the trajectory planning, the main controller 106 can determine whether the acceleration of the motion table 101 is 0±0.5 based on the displacement information. If it is within this range, it indicates that the motion table 101 is currently in uniform motion. Furthermore, when the difference between the actual motion trajectory and the preset motion trajectory is less than 100nm, the main controller 106 sends a voltage control command to the driver 105 and a switching command to the switching module 104. The above refers to the switching from the first motor 102 to the second motor 103. When switching from the second motor 103 to the first motor 102, it can be determined whether the acceleration and jerk of the motion table have reached the preset range. When they reach the preset range, it can be determined that the motion table has entered the deceleration stage from the uniform motion stage, and a switching command can be issued.

[0087] S102, the driver 105 adjusts the output voltage of the driver 105 according to the voltage control command;

[0088] S103, when the switching module 104 receives the switching command, it switches the first motor 102 and the second motor 103 to be connected according to the output voltage of the driver 105.

[0089] According to one embodiment of the present invention, such as Figure 2As shown, the switching module 104 includes an energy storage unit 1041 and a switching switch 1042. The input terminal of the energy storage unit 1041 is connected to the driver 105. One end of the switching switch 1042 is connected to the output terminal of the energy storage unit 1041, and the other end of the switching switch 1042 is connected to the first motor 102 or the second motor 103. The energy storage unit 1041 includes an energy storage circuit 10411 and a first switch 10412.

[0090] like Figure 5 As shown, when the switching module 104 receives a switching command, it switches the first motor 102 and the second motor 103 to power on based on the output voltage of the driver 105, including:

[0091] S010, when the switching module 104 receives the switching command, it controls the energy storage circuit 10411 to store energy, and when the energy storage value of the energy storage circuit 10411 reaches the target energy storage value, it disconnects the first switch 10412.

[0092] S011, control the action of switch 1042;

[0093] S012, and when the output voltage of the driver 105 reaches the target output voltage, the first switch 10412 is closed.

[0094] It should be noted that the switching switch 1042 in the switching module 104 can be activated at any time between opening and closing the first switch 10412.

[0095] For example, when the switching module 104 is connected to the first motor 102, the first switch 10412 is closed, and the switching switch 1042 is connected to the first motor 102. When the motion table 101 requires control of the second motor 103 with higher precision (e.g., in workpiece inspection), the motion table 101 switches from the acceleration phase to the constant speed motion phase. The main controller 106 sends a switching command to the switching module 104. After receiving the switching command, the switching module 104 controls the energy storage circuit 10411 to store energy. When the energy storage value of the energy storage circuit 10411 reaches the target energy storage value, it controls the first switch 10412 to open. At the same time, the main controller 106 sends a voltage control command to the driver 105 to change the output voltage of the driver 105 from matching the first motor 102 to matching the second motor 103. When the output voltage of the driver 105 matches the second motor 103, the switching switch 1042 is disconnected from the first motor 102 and connected to the second motor 103. Simultaneously, the first switch 10412 is closed. The state in which the switching module 104 is connected to the first motor 102 is switched to the state in which the switching module 104 is connected to the second motor 103. This achieves seamless switching between the first motor 102 and the second motor 103.

[0096] Taking the switching from the first motor 102 to the second motor 103 as an example, during the energy storage process of the energy storage circuit 10411, the output voltage of the driver 105 is already changing from the working voltage of the first motor 102 to the working voltage of the second motor 103, that is, from high voltage to low voltage. This process can slow down the speed of the first motor 102. When the energy storage value of the energy storage circuit 10411 reaches the target energy storage value, the first switch 10412 is opened, and the switching switch 1042 can be controlled to operate at the same time. The energy storage circuit 10411 can pre-start the second motor 103. When the output voltage of the driver 105 reaches the working voltage of the second motor 103, the first switch 10412 is closed, and the second motor 103 works normally.

[0097] Similarly, when the switching module 104 is connected to the second motor 103, the first switch 10412 is closed, and the switching switch 1042 is connected to the second motor 103. When the motion table 101 requires control by the second motor 102 with lower precision (e.g., after workpiece inspection), the motion table 101 switches from a constant speed stage to an accelerated motion stage. The main controller 106 sends a switching command to the switching module 104. After receiving the switching command, the switching module 104 controls the energy storage circuit 10411 to store energy, and when the energy storage value of the energy storage circuit 10411 reaches the target energy storage value, it controls the first switch 10412 to open. At the same time, the main controller 106 sends a voltage control command to the driver 105 to change the output voltage of the driver 105 from matching the second motor 103 to matching the first motor 102. When the output voltage of the driver 105 matches the first motor 102, the switching switch 1042 is disconnected from the second motor 103, and the switching switch 1042 is connected to the first motor 102. Simultaneously, the first switch 10412 is closed. The state of the switching module 104 connected to the second motor 103 is switched to the state of the switching module 104 connected to the first motor 102. This achieves seamless switching between the first motor 102 and the second motor 103.

[0098] Taking the switching from the second motor 103 to the first motor 102 as an example, during the energy storage process of the energy storage circuit 10411, the output voltage of the driver 105 is already changing from the working voltage of the second motor 103 to the working voltage of the second motor 102, that is, from low voltage to high voltage. This process makes the speed of the second motor 102 faster. When the energy storage value of the energy storage circuit 10411 reaches the target energy storage value, the first switch 10412 is immediately disconnected. After a period of time (during which the energy storage circuit 10411 can make the second motor 103 stop slowly), the switching switch 1042 is controlled to operate. The energy storage circuit 10411 can first pre-start the first motor 102. When the output voltage of the driver 105 reaches the working voltage of the first motor 102, the first switch 10412 is closed, and the first motor 102 works normally.

[0099] This allows for seamless switching between the first motor 102 and the second motor 103, preventing the motion table 101 from shaking during the switching process.

[0100] According to one embodiment of the present invention, the energy storage circuit is connected to the main controller; such as Figure 6 As shown, before the S011 control switch operation, the following is also included:

[0101] S0111, the main controller 106 calculates the torque of one of the first motors 102 and the second motor 103 based on the current of the energy storage circuit 10411, and estimates the torque of the other motor based on the voltage of the energy storage circuit 10411. When the difference between the torque of the first motor 102 and the torque of the second motor 103 is within a first preset range, the controller controls the switching switch 1042 to operate.

[0102] The torque difference between the two motors can be calculated using the current in the energy storage circuit 10411. Given the three-phase AC voltages Ua, Ub, and Uc, this three-phase voltage is converted into a two-phase AC voltage U. α U β The formula is:

[0103]

[0104] The formula for converting the two-phase AC voltage to the two-phase DC voltage is:

[0105]

[0106] The above is based on the first constant R of the motor. d The d-axis current of the motor can then be calculated:

[0107] I d =U d / R d ,

[0108] Given the formula for the output power of the motor, and using the motor's second constant K... T The torque F can be calculated:

[0109] F = K T *I d ,

[0110] Since the first and second constants are different for each motor, the difference in torque between the two motors (F1 is the torque of the first motor, and F2 is the torque of the second motor) can be calculated:

[0111] Δf=F1-F2

[0112] Because the switching time is shorter than the sampling period, switching within 10 steps is generally considered seamless. Therefore, the position error caused by torque fluctuations during switching can be obtained by dividing the torque fluctuation of the motion table 101 by the mass of the motion table 101 and then performing a double integral over the theoretically maximum switching period.

[0113]

[0114] The mass m of the motion stage 101 is 33 kg, the sampling period is 200 μs, and the step size t is 2000 μs. The error window s for entering uniform motion on the motion stage 101 is 100 nm, which can be obtained from the specifications. Therefore, we can obtain...

[0115]

[0116] Furthermore, when the first switch 10412 is turned off, and when the torque difference between the first motor 102 and the second motor 103 is within 1.65N, the switching switch 1042 can be controlled to operate. At this time, the vibration of the first motor 102 and the second motor 103 on the motion table 101 will not exceed the difference between the actual motion trajectory of the motion table 101 and the preset motion trajectory. Thus, the vibration of the motion table 101 is within the error range and will not affect the workpiece measurement.

[0117] According to a specific embodiment of the present invention, in the case of switching from the first motor to the second motor, such as Figure 7 As shown, the method includes the following steps:

[0118] Start; S201, determine whether the motion table has entered uniform motion. If yes, proceed to step S202; otherwise, return to step S201.

[0119] S202, determine whether the error between the preset trajectory of the motion stage and the actual motion trajectory is less than 100nm. If yes, proceed to step S203; otherwise, return to step S202.

[0120] S203, the main controller sends a voltage control command to the driver and a switching command to the switching module at the same time;

[0121] S204, determine whether the energy storage value of the energy storage circuit has reached the target energy storage value. If yes, proceed to step S205; otherwise, return to step S204.

[0122] S205, disconnect the first switch;

[0123] S206, the main controller obtains the current of the energy storage circuit and calculates the torque of the first motor, and estimates the torque of the second motor based on the voltage of the energy storage circuit;

[0124] S207. Determine whether the difference between the torque of the first motor and the torque of the second motor is less than 1.65N. If yes, proceed to step S208; otherwise, return to step S206.

[0125] S208 controls the operation of the switching switch;

[0126] S209, determine whether the output voltage of the driver reaches the working voltage of the second motor. If yes, proceed to step S210; otherwise, return to step S209.

[0127] S210, close the first switch; end.

[0128] This completes the switch from the first motor to the second motor.

[0129] It should be noted that, in the above embodiments, after switching from the first motor to the second motor, to ensure safety, it is also necessary to check whether the first motor has been properly disconnected and stopped. If not, an emergency stop should be performed on the motion table. Additionally, it is also necessary to check whether the second motor switch is properly connected and whether the second motor has started normally.

[0130] Based on this, the method is effective and layout-friendly, reducing costs. On the other hand, by switching the output between the two motors, it can be ensured that the motors operate within their normal operating range at any time during switching, avoiding sudden increases or decreases in motor speed when switching drivers.

[0131] In summary, the motor switching device and method for a motion table proposed in the embodiments of the present invention include: a motion table; a first motor, a second motor, a switching module, a driver, and a main controller. The output terminal of the first motor is connected to the motion table, and the first motor is used to control the motion table to move at a first precision. The output terminal of the second motor is connected to the motion table, and the second motor is used to control the motion table to move at a second precision. The first precision is greater than the second precision. The output terminal of the switching module is connected to the input terminals of the first motor and the second motor, respectively. The output terminal of the driver is connected to the input terminal of the switching module. The main controller is connected to the input terminal of the driver and the control terminal of the switching module, respectively, and the main controller is used to control the switching module to switch between the first motor and the second motor. Therefore, by using this motor switching device for the motion table, only one driver and two motors are needed to achieve motion control of the motion table at different precisions. This not only ensures the precision of the motion control but also reduces product cost and integration difficulty, thereby enhancing product competitiveness.

[0132] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A motor switching device for a motion table, characterized in that, include: Sports table; A first motor, the output end of which is connected to the motion table, is used to control the motion table to move at a first precision. A second motor, the output of which is connected to the motion table, is used to control the motion table to move at a second precision; wherein the first precision is less than the second precision. A switching module, the output of which is connected to the input of the first motor and the input of the second motor, respectively; A driver, the output of which is connected to the input of the switching module; The main controller is connected to the input terminal of the driver and the control terminal of the switching module. The main controller is used to control the switching module to switch between the first motor and the second motor. The switching module includes an energy storage unit and a switching switch. The input terminal of the energy storage unit is connected to the driver. One end of the switching switch is connected to the output terminal of the energy storage unit, and the other end of the switching switch is connected to the first motor or the second motor. The energy storage unit includes an energy storage circuit and a first switch.

2. The motor switching device for the motion table according to claim 1, characterized in that, The main controller is also used to control the output voltage of the driver and send a switching command to the switching module. The switching module is used to switch the first motor and the second motor on and off according to the output voltage of the driver and the switching command.

3. The motor switching device for the motion table according to claim 1, characterized in that, The energy storage circuit is also connected to the main controller. The main controller calculates the torque of one of the first motor and the second motor based on the current of the energy storage circuit, estimates the torque of the other motor based on the voltage of the energy storage circuit, and controls the switching switch to operate based on the torque of the first motor and the torque of the second motor.

4. The motor switching device for the motion table according to claim 1 or 2, characterized in that, Also includes: The measurement unit, connected to the main controller, is used to measure the displacement information of the motion table and send the displacement measurement signal to the main controller. The main controller is used to send a switching command to the switching module based on the displacement measurement signal and control the output voltage of the driver.

5. The motor switching device for the motion table according to claim 4, characterized in that, The measuring unit includes multiple laser rulers, each of which is arranged around the motion table.

6. A method for switching motors on a motion table, characterized in that, Based on the motor switching device of the motion table according to any one of claims 1-5, the method includes the following steps: The main controller sends voltage control commands to the driver and switching commands to the switching module; The driver adjusts its output voltage according to the voltage control command; When the switching module receives the switching command, it switches between the first motor and the second motor according to the output voltage of the driver.

7. The motor switching method for the motion table according to claim 6, characterized in that, The switching module includes an energy storage unit and a switching switch. The input terminal of the energy storage unit is connected to the driver. One end of the switching switch is connected to the output terminal of the energy storage unit, and the other end of the switching switch is connected to the first motor or the second motor. The energy storage unit includes an energy storage circuit and a first switch. When the switching module receives the switching command, it switches the first motor and the second motor on according to the output voltage of the driver, including: When the switching module receives the switching command, it controls the energy storage circuit to store energy, and disconnects the first switch when the energy storage value of the energy storage circuit reaches the target energy storage value. Control the operation of the switching switch; When the output voltage of the driver reaches the target output voltage, the first switch is closed.

8. The motor switching method for the motion table according to claim 7, characterized in that, The energy storage circuit is connected to the main controller; Before controlling the operation of the switching switch, the following is included: The main controller calculates the torque of one of the first motors and the second motor based on the current of the energy storage circuit, and estimates the torque of the other motor based on the voltage of the energy storage circuit. When the difference between the torque of the first motor and the torque of the second motor is within a first preset range, the controller controls the switching switch to operate.

9. The motor switching method for the motion table according to claim 6, characterized in that, The motor switching device of the motion table further includes: a measurement unit, connected to the main controller, used to measure the displacement information of the motion table and send a displacement measurement signal to the main controller; Before the main controller sends voltage control commands to the driver and switching commands to the switching module, the process includes: The main controller receives the displacement measurement signal; When the displacement measurement signal is within the second preset value range, the main controller sends a voltage control command to the driver and a switching command to the switching module.

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