Error correction method for an eccentric disc shaft angle encoder

Abstract

The application discloses an error correction method of an eccentric disc shaft angle encoder. The core part of the encoder comprises a light emitting tube control board and a receiving tube control board which are coaxially installed in sequence. The light emitting tube control board and the receiving tube control board are uniformly provided with light emitting tubes / receiving tubes, thermocouples and temperature sensors along the circumference to form temperature control nodes and sensor arrays. A control algorithm is adopted to obtain a uniform temperature field in the working space of the light emitting tubes and the receiving tubes. The control method comprises the following steps: collecting temperature parameters of each point to form a temperature area parameter list; comparing the preset temperature to calculate the temperature difference of each area control node and selecting a heating / cooling mode according to the temperature difference; and outputting a driving current to the thermocouple of the corresponding area according to the size of the temperature difference. The application can output four standard amplitude and phase sinusoidal signals through the optimization and tuning of the constant temperature control, signal zero adjustment, amplitude adjustment and phase adjustment and other related functional modules, eliminates errors and does not need to invest a large amount of computing power for software error correction.

Description

Technical Field

[0001] This invention relates to the field of encoder technology, specifically to an error correction method for an eccentric disc shaft angle encoder. Background Technology

[0002] With the technological development of the automotive industry, the digitalization and intelligence of vehicles have been rapidly promoted, and shaft angle encoders, which are widely used in vehicle AEBS and ESC functions, have also been promoted.

[0003] However, the harsh working environment of vehicles poses a significant challenge for encoders. Temperature fluctuations due to altitude changes during driving, as well as extreme cold and heat, can cause substantial shifts in the operating state of photoelectric components. Ensuring accurate readings becomes a critical issue. Operating temperature greatly affects the stability of electronic devices, especially photoelectric components. Because LEDs have lower light-gathering efficiency and accumulate more heat than other electronic devices, photoelectric components exhibit significant temperature drift. Therefore, the operating temperature of the encoder greatly impacts system accuracy. Temperature changes during vehicle operation cause substantial variations in the encoder's operating temperature, leading to shifts in the operating state of the LEDs, receivers, and their delicate electronic systems, resulting in significant deviations in encoder readings. Summary of the Invention

[0004] The purpose of this invention is to provide an eccentric disc shaft angle encoder to solve the problem that in the prior art, the processing and assembly errors of the eccentric disc shaft angle encoder have a great impact on the accuracy, and the error cannot be compensated by the method of correction coefficient.

[0005] The present invention solves the above problems through the following technical solution:

[0006] An error correction method for an eccentric disk shaft angle encoder, the encoder comprising a rear cover, an encoder core, and a mounting panel coaxially mounted sequentially. The encoder core includes a light-emitting diode (LED) control board, an LED lamp holder, an eccentric disk, a receiver lamp holder, and a receiver control board coaxially mounted sequentially. LEDs and LED control board temperature differential plates are evenly distributed along the circumference of the LED control board; receiver tubes and receiver control board temperature differential plates are evenly distributed along the circumference of the receiver control board. One end of the LED control board temperature differential plate is attached to the LED lamp holder, and the other end is attached to the rear cover. One end of the receiver control board temperature differential plate is attached to the receiver lamp holder, and the other end is attached to the mounting panel. Temperature sensors are arranged in the areas where the LED and receiver control board temperature differential plates are located, forming a sensor array. The temperature differential plates form temperature control nodes. By employing a control algorithm, a uniform temperature field can be obtained in the working space of the LEDs and receiver tubes. The method includes:

[0007] Step S110: Collect temperature parameters at each point using a temperature sensor;

[0008] Step S120: Using the temperature difference sheet of the LED control board and the temperature difference sheet of the receiver control board as regional control nodes, the acquisition area is divided into multiple sub-temperature zones to form a temperature zone parameter list.

[0009] Step S130: According to the sub-temperature parameter list, compare the corresponding area preset temperature and calculate the temperature difference of each area control node.

[0010] Step S140: Select the heating / cooling mode according to the positive / negative temperature difference, and select the preset control algorithm to output the control voltage according to the temperature difference of the area control node (e.g., select the corresponding preset level control mode and output the preset level control voltage).

[0011] Step S150: Based on the input branch, control voltage, and polarity, output a drive current of the corresponding polarity to the thermocouple in the corresponding area.

[0012] Furthermore, it also includes a constant current control method for the LED, specifically:

[0013] The reference voltage module on the LED control board outputs a reference voltage to the comparator. The comparator compares the reference voltage with the sampling voltage fed back by the sampling resistor and then provides an adjusted output voltage to the power transistor. The output current of the power transistor is adjusted according to the change of the input voltage. This current flows through the power transistor, the LED, and the sampling resistor, generating a new sampling voltage on the sampling resistor, which is then fed back to the comparator to form constant current control of the LED.

[0014] Furthermore, it also includes a signal zeroing and amplitude modulation control method for the receiving tube, specifically including: inputting the input signal received by the receiving tube and the zeroing control level together into a subtraction operational amplifier; adjusting the zeroing control level to pull the trough level of the input signal down to 0; the zeroed signal is input into the operational amplifier and output; the adjustable feedback network adjusts the amplifier's amplification factor according to the input amplitude modulation control signal and the output feedback of the operational amplifier, thereby pulling the peak level of the input signal up to a preset peak value.

[0015] Furthermore, the light-emitting diodes are eight infrared light-emitting diodes distributed along the circumference of the light-emitting diode control board, and the receiving diodes are eight infrared receiving diodes distributed along the circumference of the receiving diode control board. By setting eight sets of reading heads and using data from adjacent 45° reading heads to correct the phase of the reading head, eight sinusoidal signals with a standard phase difference of 45° or four sinusoidal signals with a standard phase difference of 90° can be formed, specifically including:

[0016] Step S310: Compress the peak values ​​of the input n-45° head, n° head, and n+45° head sine signals;

[0017] Step S320: Connect the reference encoder via coaxial or high-precision gear, and use a feasible error acquisition method to check the phase error of S0. If there is no phase difference, proceed to step S330; if the phase is lagging, proceed to step S340; if the phase is leading, proceed to step S350.

[0018] Step S330: Turn off the analog switches at the back end of the input amplifiers of the n-45° head and the n+45° head, so that the 0° head signal is directly sent to the adder operational amplifier, and then the amplitude modulation and zeroing circuit is used to restore its peak value.

[0019] Step S340 includes:

[0020] 1) Enable the analog switch at the back end of the n-45° head input amplifier so that the output signal of this channel participates in phase subdivision together with the 0° head signal, obtaining ((θ n-45 +θ n ) / 2)+θ n The initial phase signal is 1 / 2, and then the signal amplitude is compressed.

[0021] 2) Select a single or multiple initial phase signals based on the difference in phase lag;

[0022] 3) Integrate the selected single or multiple initial phase signals with the 0° head signal, and then output them after amplitude modulation and zeroing;

[0023] Step S350 includes:

[0024] 1) Enable the analog switch at the back end of the n+45° head input amplifier so that the output signal of this channel participates in phase subdivision together with the 0° head signal, obtaining ((θ n+45 +θ n ) / 2)+θ n The initial phase signal is 1 / 2, and then the signal amplitude is compressed.

[0025] 2) Select a single or multiple initial phase signals based on the difference in phase lag;

[0026] 3) Integrate the selected single or multiple initial phase signals with the 0° head signal, and then output them after amplitude modulation and zeroing.

[0027] Furthermore, the rear cover is provided with a bottom housing bearing collar, and a bottom housing bearing is installed inside the bottom housing bearing collar. The outer shaft surface of the bottom housing bearing is tightly fitted with the bottom housing bearing collar, and the inner shaft surface of the bottom housing bearing is tightly fitted with the main shaft of the encoder core part. The rear cover is provided with a first threaded hole. The encoder core part includes, in sequence, a light-emitting tube control board, a light-emitting tube holder, an eccentric disk, a receiver tube holder, and a receiver tube control board. A light-emitting tube is provided on the light-emitting tube control board. The light-emitting tube is coaxially assembled with the light-emitting tube holder light-transmitting hole provided on the light-emitting tube holder. The inner diameter of the light-transmitting hole of the light-emitting tube holder is adapted to the outer diameter of the light-emitting tube. The receiver tube control board... A receiving tube is provided, which is coaxially assembled with the light-transmitting hole of the receiving tube lamp holder. The inner diameter of the light-transmitting hole of the receiving tube lamp holder is adapted to the outer diameter of the receiving tube. The axial end face of the light-emitting tube lamp holder coincides with that of the receiving tube lamp holder and is coaxially assembled with the eccentric disk, and is located on both sides of the eccentric disk respectively. A panel bearing collar is provided in the mounting panel, and a panel bearing is coaxially assembled with the panel bearing collar. The panel bearing is coaxially installed with the bearing spindle of the eccentric disk. The bearing spindle of the eccentric disk passes through the core part of the encoder and is coaxially connected with the bottom shell bearing. The mounting panel is provided with a second threaded hole corresponding to the first threaded hole.

[0028] Furthermore, the diameter of the eccentric disk is the same as the diameter of the center of the eight light-transmitting holes of the light-emitting tube holder and the light-receiving tube holder. The eccentricity of the eccentric disk is slightly smaller than the radius of the light-transmitting holes on the light-emitting tube holder and the light-receiving tube holder. When the eccentric disk rotates, the area of ​​the corresponding light-transmitting hole blocked by the eccentric disk changes.

[0029] Furthermore, a positioning strip is provided on the outer side of the bottom bearing collar, and a positioning groove is provided on the outer side of the encoder core part to fit tightly with the positioning strip.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] (1) This invention, through optimization and tuning of relevant functional modules, can output four standard amplitude and phase sinusoidal signals. Firstly, information from adjacent ±45° phase signals is used during the tuning process to increase the entropy of the four signals. Secondly, the amplitude and phase of the tuned signals already meet the requirements, eliminating the need for subsequent error correction, thus improving data processing efficiency and significantly increasing the speed at which the encoder outputs accurate angle information, providing stronger support for high-speed and high-precision applications. Thirdly, through high-precision constant current and temperature control, the operating state of key encoder components will not deviate with changes in ambient temperature and operating time, ensuring high-precision readings in harsh and variable environments, making it more suitable for military vehicle and aerospace applications.

[0032] (2) The present invention reduces the processing and assembly error of the eccentric disk shaft angle encoder by coaxially mounting the back cover, light-emitting tube control board, light-emitting tube lamp holder, eccentric disk, receiver lamp holder and receiver control board and mounting panel, and coaxially mounting the light-emitting tube, receiver tube and light-transmitting hole.

[0033] (3) In this invention, the diameter of the eccentric disk is consistent with the circumference diameter of the uniformly distributed light-transmitting holes. To avoid the loss of peak and valley signals caused by processing and assembly errors, the eccentricity should be set to a parameter slightly smaller than the radius of the light-transmitting holes, depending on the actual situation. When the eccentric disk rotates, the area of ​​the corresponding light-transmitting holes blocked by the eccentric disk changes. Under the condition that the light power of the 8 sets of reading heads is constant, the current flowing through the receiving tube of the reading head will change accordingly. When the eccentric disk rotates one revolution, a sinusoidal current signal with a phase difference of 45° will be generated in the receiving tube of the 8 sets of reading heads. Attached Figure Description

[0034] Figure 1 This is a block diagram of the encoder function structure of the present invention;

[0035] Figure 2 This is a block diagram illustrating the principle of regional constant temperature control in this invention.

[0036] Figure 3 This is a flowchart of the constant temperature control process;

[0037] Figure 4 This is a block diagram of a high-precision constant current source for LEDs.

[0038] Figure 5 Schematic diagram of a high-precision constant current source for LEDs at the μA level;

[0039] Figure 6 This is a block diagram illustrating the principle of amplitude modulation and zero adjustment for signals.

[0040] Figure 7 This is a schematic diagram of the signal amplitude modulation and zeroing principle.

[0041] Figure 8 This is a schematic diagram of the phase calibration function structure of a single-group reading head;

[0042] Figure 9 Flowchart for single-group reading head phase calibration;

[0043] Figure 10 This is a schematic diagram of the overall structure of the encoder;

[0044] Figure 11 This is a schematic diagram of the assembly of the encoder core and the back cover.

[0045] Figure 12 This is an assembly diagram of the mounting panel and the bottom shell assembly;

[0046] Figure 13This is an assembly diagram of the encoder core component;

[0047] Figure 14 This is an exploded view of the encoder;

[0048] Figure 15 This is a schematic diagram showing the fit between the eccentric disk and the LED holder;

[0049] The components are as follows: 1-Rear cover; 2-Encoder core part; 3-Mounting panel; 11-Bottom housing bearing collar; 12-Positioning strip; 13-Bottom housing bearing; 14-Rear cover threaded hole; 21-Light-emitting tube control board; 22-Light-emitting tube lamp holder; 23-Eccentric disk; 24-Receiver tube lamp holder; 25-Receiver tube control board; 26-Positioning groove; 31-Panel bearing; 32-Mounting panel threaded hole; 33-Panel bearing collar; 211-Light-emitting tube; 212-Light-emitting tube control board temperature difference plate; 221-Light-emitting tube lamp holder light transmission hole; 231-Eccentric disk bearing spindle; 241-Receiver tube lamp holder light transmission hole; 251-Receiver tube; 252-Receiver tube control board temperature difference plate. Detailed Implementation

[0050] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0051] Example 1:

[0052] Combination Figure 1 and Figure 10 As shown, an error correction method for an eccentric disk shaft angle encoder is disclosed. The encoder includes a rear cover 1, an encoder core part 2, and a mounting panel 3, which are coaxially mounted sequentially. The encoder core part 2 includes a light-emitting diode control board 21, a light-emitting diode lamp holder 22, an eccentric disk 23, a receiver tube lamp holder 24, and a receiver tube control board 25, which are coaxially mounted sequentially. Light-emitting diodes 211 and light-emitting diode control board temperature difference plates 212 are evenly distributed along the circumference of the light-emitting diode control board 21. Receiver tubes 251 and receiver tube control board temperature difference plates 252 are evenly distributed along the circumference of the receiver tube control board 25. One end of the plate temperature difference plate 212 is attached to the light-emitting tube lamp holder 22, and the other end is attached to the back cover 1. One end of the receiving tube control plate temperature difference plate 252 is attached to the receiving tube lamp holder 24, and the other end is attached to the mounting panel 3. Temperature sensors are provided in the areas where the light-emitting tube control plate temperature difference plate 212 and the receiving tube control plate temperature difference plate 252 are located. This invention uses multiple sensors to form a temperature sensor array and multiple temperature difference plates to form control nodes. By using a reasonable control algorithm, a uniform temperature field can be obtained in the working space of the light-emitting tube and the receiving tube, so as to achieve a fine design of the regional constant temperature system.

[0053] Temperature control in the temperature difference zone, such as Figure 2 As shown:

[0054] Temperature sensor array: forms a regional coverage and collects temperature parameters at various points within the region.

[0055] Regional temperature parameter calculation decomposition: Using temperature difference plates as regional control nodes, the acquisition area is divided into multiple sub-temperature zones, forming a sub-temperature zone parameter list, and the temperature gradient within the region is calculated.

[0056] Regional temperature requirements: Based on the sub-temperature zone parameter list, compare the required temperature values ​​with the design values ​​and calculate the temperature difference of each control node.

[0057] Sub-region current graded control: The heating / cooling mode is selected based on the sign of the temperature difference. According to the magnitude of the temperature difference at this control node, the corresponding control algorithm, such as PD / PI / PID or other control methods, is selected, and the control voltage for that level is output.

[0058] Heating / cooling branch current control: Based on the input branch selection and control voltage, the corresponding polarity of the drive current is output. The polarity of the drive current can be selected through a bridge or other means.

[0059] Fault diagnosis module: Through special algorithms, it can identify abnormal situations such as temperature imbalance, sensor failure, and thermocouple drive failure, so as to avoid the user using incorrect data.

[0060] Thermostat constant temperature control process as follows Figure 3 As shown:

[0061] The first step is to acquire the temperature parameters of the temperature sensor array and form a parameter list.

[0062] The second step is to create a sub-temperature region parameter list: using the temperature difference plate as the region control node, the acquisition area is divided into multiple sub-temperature regions, and the temperature parameter list is divided into multiple sub-temperature region parameter lists. The parameter gradient within each region is calculated to prepare for subsequent determination of whether to use an overshoot adjustment-like overshoot method and threshold setting.

[0063] The third step is to compile a sub-temperature zone temperature difference list: based on the sub-temperature zone parameter list, compare the required design temperature values ​​and calculate the temperature difference for each control node.

[0064] The fourth step is to iterate through the list: query the temperature difference value of each sub-region and determine whether the adjustment control of the temperature difference plate needs to be output.

[0065] Fifth step, current polarity determination: Select the heating or cooling branch to enable based on the positive or negative value of the temperature difference.

[0066] Step 6, Dynamic Threshold Adjustment: Based on the overshoot feedback from the "Sub-temperature Zone Parameter List", dynamically set the control threshold for the sub-zone and execute appropriate overshoot control.

[0067] Step 7, Current control method: Select different control methods, such as PD, PID, or other effective control methods, based on the dynamically set threshold.

[0068] Step 8, Switching Regions: After the control adjustment of this sub-region is completed, return to Step 4 and check if there is another sub-region that needs output control. If there is, continue executing Steps 4 through 8. If not, jump to Step 1, re-acquire the temperature sensor array parameters after output control, and execute the judgment process of Steps 1 through 4.

[0069] Temperature sensors on the LED control board and receiver control board are generally evenly distributed according to the temperature acquisition area, or the key areas to be monitored according to design requirements.

[0070] This invention employs a method where one end of a thermocouple on a LED control board is attached to the LED lamp holder to maintain a constant lamp holder temperature. This ensures the LED and control board operate at a predetermined constant temperature, reducing the impact of temperature drift on system accuracy. The other end of the thermocouple is attached to the encoder back cover. Since the surface area of ​​the back cover is much larger than that of the lamp holder, the metal back cover allows for rapid heat dissipation. Similarly, one end of a thermocouple on a receiver control board is attached to the receiver lamp holder to maintain a constant lamp holder temperature, ensuring the receiver and control board operate at a predetermined constant temperature and preventing temperature drift from affecting the system. The other end of the thermocouple is attached to the encoder mounting panel. Again, the surface area of ​​the mounting panel is much larger than that of the lamp holder, allowing for rapid heat dissipation and ensuring the system operates at a constant temperature.

[0071] Example 2:

[0072] Based on Example 1, such as Figure 4 As shown, it also includes a constant current control method for the LED, specifically:

[0073] The reference voltage module on the LED control board outputs a reference voltage to the comparator. The comparator compares the reference voltage with the sampled voltage fed back from the sampling resistor and then provides an adjusted output voltage to the power transistor. The output current of the power transistor is adjusted according to the change in input voltage. This current flows through the power transistor, the LED, and the sampling resistor, generating a new sampled voltage across the sampling resistor, which is then fed back to the comparator, forming the constant current control of the LED. The accuracy of the constant current control is related to the resistance value of the sampling resistor and the design of the comparator, and should be adjusted specifically according to the operating point parameters of the LED. Figure 5 To achieve Figure 4 A specific circuit schematic for the function shows that, through actual testing, the circuit can achieve a constant current control accuracy of ±1uA.

[0074] Example 3:

[0075] Based on Example 1 or 2, combined with Figure 6 As shown, it also includes a signal zeroing and amplitude modulation control method for the receiving tube, specifically including:

[0076] Regarding the zero-adjustment function: The input signal received by the receiving tube and the zero-adjustment control level are input together to the subtraction operational amplifier. By adjusting the zero-adjustment control level, the trough level of the input signal is pulled down to 0.

[0077] Regarding amplitude modulation (AM) functionality: After zeroing, the signal is input to the operational amplifier. In principle, the operational amplifier's amplification factor is controlled by a feedback network, commonly a feedback resistor. Changing the value of the feedback resistor alters the operational amplifier's amplification factor, thus achieving the designed signal peak. The step precision of the amplification factor is related to the step precision of the feedback resistor. Figure 7 To achieve Figure 6 This invention provides a specific circuit schematic for a function, but is not limited thereto.

[0078] Example 4:

[0079] Based on Example 3, the light-emitting tube is 8 infrared light-emitting diodes distributed around the circumference of the light-emitting tube control board, and the receiving tube is 8 infrared receiving diodes distributed around the circumference of the receiving tube control board. By setting 8 sets of reading heads and using the data from adjacent 45° reading heads to correct the phase of the reading head, 8 sinusoidal signals with a standard phase difference of 45° or 4 sinusoidal signals with a standard phase difference of 90° can be formed, and the information content of the signal is greatly improved during the correction process.

[0080] Single-channel reading head phase calibration function architecture as follows Figure 8 As shown, it is divided into a signal input module, a phase subdivision module, and a phase integration module, wherein:

[0081] Signal input module: Taking 0° head calibration as an example, the signals from the 0° head and the front and rear 45° heads after amplitude modulation and zeroing are input to the input amplifier of the phase modulation circuit to compress the signal amplitude and avoid exceeding the amplitude limit after subsequent addition by operational amplifier.

[0082] Phase subdivision module: Taking the 0° head signal phase lag as an example, the analog switch at the back end of the -45° head input amplifier should be enabled, while the analog switch at the back end of the 45° head should be disabled. This sends the 0° head and -45° head signals into the first-stage adder operational amplifier, thus obtaining approximately half of the sum of their initial phases, i.e., approximately (θ... -45 +θ0) / 2. Then, this signal is fed into the second-stage adder operational amplifier to perform addition with the 0° head signal, thus obtaining ((θ0) / 2. -45The initial phase signal is obtained by subdividing the initial phase signal into +θ0) / 2)+θ0) / 2, while compressing the signal amplitude to prevent the amplitude of subsequent stages from exceeding the limit. Using this phase subdivision method, increasingly finer initial phase signals are obtained in later stages. Then, by enabling the analog switches at the back end of each stage's adder operational amplifier, a single or multiple initial phase signals of appropriate stages are selected for output to the back end for phase integration. In this stage, another 45° initial phase signal can be subdivided into each stage, which, along with the -45° initial phase signals, serves as a pool of alternative signals for subsequent stage phase integration.

[0083] Phase integration module: One or more appropriate initial phase signals and 0° head signals selected from the phase subdivision module are input together to the adder operational amplifier of the phase integration module, which outputs a standard initial phase sine wave signal of the 0° head that meets the design requirements. Then, the peak-to-peak value of the signal is corrected by the amplitude modulation and zeroing circuit to obtain the standard sine wave signal of the reading head.

[0084] Phase calibration flowchart, as follows Figure 9 As shown, the details are as follows:

[0085] The first step is to compress the signal amplitude: by adjusting the gain parameters of the high-precision operational amplifier, the peak values ​​of the input -45°, 0°, and 45° sinusoidal signals are compressed. The compression amplitude is adjusted according to the number of subdivision stages in the subsequent stage.

[0086] The second step is to collect signal phase error: connect the reference encoder via a coaxial or high-precision gear and use a feasible error collection method to check the S0 phase error.

[0087] The third step is signal phase correction:

[0088] No phase difference: Turn off the analog switches at the back end of the -45° head and 45° head input amplifiers, and turn off the analog switches of each stage of the phase subdivision module. Let the 0° head signal be directly sent to the adder operational amplifier of the phase integration module. At this time, the adder operational amplifier only has this signal input, so the output signal will also be in phase and amplitude. Then, the amplitude and zeroing circuit can be used to restore its peak-to-peak value.

[0089] Phase lag: If S0 phase lags:

[0090] 1) Enable the analog switch at the back end of the -45° head input amplifier, so that the signal output from this path is sent to the phase subdivision module to participate in phase subdivision together with the 0° head signal. This results in ((θ) -45 The initial phase signal is obtained by subtracting the initial phase signal from the phase subdivision signal (+θ0) / 2). The signal amplitude is then compressed to prevent the amplitude from exceeding limits in subsequent stages. Following this phase subdivision method, increasingly finer initial phase signals are obtained in later stages.

[0091] 2) Based on the difference in phase lag, select one or more appropriate initial phase signals by enabling the analog switches at the back end of each stage of the adder operational amplifier.

[0092] 3) The selected single or multiple corresponding initial phase signals are phase integrated with the 0° head signal by an adder operational amplifier, and then output after amplitude modulation and zeroing.

[0093] Phase Lead: If S0 phase leads

[0094] 1) Enable the analog switch at the back end of the +45° head input amplifier, so that the signal output from this path is sent to the phase subdivision module to participate in phase subdivision together with the 0° head signal. This results in ((θ) +45 The initial phase signal is obtained by subtracting the initial phase signal from the phase subdivision signal (+θ0) / 2). The signal amplitude is then compressed to prevent the amplitude from exceeding limits in subsequent stages. Following this phase subdivision method, increasingly finer initial phase signals are obtained in later stages.

[0095] 2) Based on the difference in phase lag, select one or more appropriate initial phase signals by enabling the analog switches at the back end of each stage of the adder operational amplifier.

[0096] 3) The selected single or multiple corresponding initial phase signals are phase integrated with the 0° head signal by an adder operational amplifier, and then output after amplitude modulation and zeroing.

[0097] Step 4, repeat verification: Continue with step 3, check the S0 phase until its phase meets the requirements, and the phase calibration process is complete.

[0098] Example 5:

[0099] Based on Example 1, combined with Appendix Figures 10-15 As shown, the rear cover 1 has a bottom shell bearing collar 11 inside, and a bottom shell bearing 13 is installed inside the bottom shell bearing collar 11. The outer shaft surface of the bottom shell bearing 13 is tightly fitted with the bottom shell bearing collar 11, and the inner shaft surface of the bottom shell bearing 13 is tightly fitted with the main shaft of the encoder core part 2. The rear cover 1 is provided with a first threaded hole.

[0100] The encoder core component 2 comprises, in sequence, a light-emitting diode control board 21, a light-emitting diode holder 22, an eccentric disk 23, a receiver diode holder 24, and a receiver diode control board 25. The light-emitting diode control board 21 is equipped with a light-emitting diode 211, which is coaxially assembled with a light-transmitting hole on the light-emitting diode holder 22. The inner diameter of the light-transmitting hole 221 on the light-emitting diode holder 22 is adapted to the outer diameter of the light-emitting diode 211. The receiver diode control board 25 is equipped with a receiver diode 251, which is coaxially assembled with a light-transmitting hole 241 on the receiver diode holder 24. The inner diameter of the light-transmitting hole 241 on the receiver diode holder 24 is adapted to the outer diameter of the light-transmitting diode 211. The outer diameter of tube 251 is compatible; the axial end faces of the light-emitting tube holder 22 and the receiving tube holder 24 coincide and are coaxially assembled with the eccentric disk 23, and are respectively located on both sides of the eccentric disk 23. Furthermore, the outer axial surfaces of the light-emitting tube holder 22 and the receiving tube holder 24 are provided with positioning grooves 26 that are tightly fitted with the bottom shell of the rear cover 1, ensuring the coaxiality of the eight sets of light gaps of the two lamp holders from a machining perspective; the light-emitting tubes on the light-emitting tube control board 21 are welded to the light-emitting tube control board 21, which is a hard connection. It is coaxially assembled with the light-transmitting hole of the light-emitting tube holder 22. The light-transmitting hole of the light-emitting tube holder 22 is consistent with the light-emitting tube, so it can be regarded as a hard connection, thereby making the light-emitting tube control board 21 stably installed on the light-emitting tube holder 22. The receiving tube control board 25 and the receiving tube lamp holder 24 are installed in the same way; the encoder core part 2 is provided with a positioning groove 26; the light-emitting tube control board 21 is provided with a light-emitting tube control board temperature difference plate 212, and the receiving tube control board 25 is provided with a receiving tube control board temperature difference plate 252, which are used to adjust the working temperature of the light-emitting tube control board 21 and the receiving tube control board 25.

[0101] Mounting panel 3 is manufactured using an aluminum alloy die-casting and milling process. It contains a panel bearing collar 33. Mounting panel 3 is coaxially mounted with the outer shaft surface of panel bearing 31 via the panel bearing collar 33, and with the inner shaft surface of panel bearing 31 coaxially with the eccentric disc bearing main shaft 231. The eccentric disc bearing main shaft 231 passes through the encoder core part 2 and is coaxially and tightly fitted with the inner shaft surface of the bottom housing bearing 13. The bottom housing bearing 13 is also coaxially and tightly fitted with the bottom housing bearing collar 11. A positioning strip 12 is provided on the outer side of the bearing mounting collar 11, which is tightly fitted with the positioning groove 26 of the encoder core part 2. Pushing the encoder core part 2 to the bottom of mounting panel 3 forms the encoder bottom housing assembly. The outer diameter shaft surface of panel bearing 31 is axially assembled with panel bearing collar 33. The threaded hole 14 of the rear cover and the threaded hole 32 of the mounting panel are coaxially assembled, with their end faces overlapping (i.e., pushed to the bottom), thus forming the encoder assembly.

[0102] Furthermore, the light-emitting diodes are multiple infrared light-emitting diodes distributed along the circumference of the light-emitting diode control board 21, and the receiving diodes are multiple infrared receiving diodes distributed along the circumference of the receiving diode control board 25, with the same number as the infrared light-emitting diodes. Preferably, the number of both infrared light-emitting diodes and infrared receiving diodes is eight.

[0103] Furthermore, the diameter of the eccentric disk 23 is the same as the diameter of the light-emitting tube holder 22 and the light-receiving tube holder 24. The eccentricity of the eccentric disk 23 is slightly smaller than the radius of the light-transmitting holes on the light-emitting tube holder 22 and the light-receiving tube holder 24. When the eccentric disk 23 rotates, the area of ​​the corresponding light-transmitting hole blocked by the eccentric disk 23 changes.

[0104] This invention, through optimization and tuning of related functional modules such as constant temperature control, signal zeroing, amplitude modulation, and phase modulation, can output four standard amplitude and phase sinusoidal signals, eliminating errors and eliminating the need for subsequent software error correction with a large amount of computing power. It has great application value in the field of rapid and accurate reading.

[0105] Although the present invention has been described herein with reference to illustrative embodiments, the above embodiments are merely preferred embodiments of the present invention, and the implementation of the present invention is not limited to the above embodiments. It should be understood that those skilled in the art can devise many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. An error correction method for an eccentric disc shaft angle encoder, characterized in that, The encoder includes a rear cover, an encoder core, and a mounting panel, all coaxially mounted in sequence. The encoder core includes a LED control board, an LED holder, an eccentric disc, a receiver holder, and a receiver control board, all coaxially mounted in sequence. LEDs and LED control board temperature differential plates are evenly distributed along the circumference of the LED control board. Receiver tubes and receiver control board temperature differential plates are also evenly distributed along the circumference of the receiver control board. One end of each LED control board temperature differential plate is attached to the LED holder, and the other end is attached to the rear cover. One end of each receiver control board temperature differential plate is attached to the receiver holder, and the other end is attached to the mounting panel. Temperature sensors are installed in the areas where the LED control board temperature differential plates and receiver control board temperature differential plates are located. The method includes: Step S110: Collect temperature parameters at each point using a temperature sensor; Step S120: Using the temperature difference sheet of the LED control board and the temperature difference sheet of the receiver control board as regional control nodes, the acquisition area is divided into multiple sub-temperature zones to form a temperature zone parameter list. Step S130: According to the sub-temperature parameter list, compare the corresponding area preset temperature and calculate the temperature difference of each area control node. Step S140: Select the heating / cooling mode according to the positive / negative temperature difference, select the corresponding preset level control mode according to the size of the temperature difference of the area control node, and output the preset level control voltage. Step S150: Based on the input branch and control voltage, output a drive current of the corresponding polarity to the thermocouple in the corresponding area; It also includes a signal zeroing and amplitude modulation control method for the receiving tube, specifically including: inputting the input signal received by the receiving tube and the zeroing control level together into a subtraction operational amplifier; by adjusting the zeroing control level, pulling the trough level of the input signal down to 0; the zeroed signal is input into the operational amplifier and output; the adjustable feedback network adjusts the amplifier's amplification factor according to the input amplitude modulation control signal and the output feedback of the operational amplifier, pulling the peak level of the input signal up to a preset peak value; The light-emitting diodes are eight infrared light-emitting diodes distributed around the circumference of the light-emitting diode control board, and the receiving diodes are eight infrared receiving diodes distributed around the circumference of the receiving diode control board. By setting eight sets of reading heads and using data from adjacent 45° reading heads to correct the phase of the reading head, eight sinusoidal signals with a standard phase difference of 45° or four sinusoidal signals with a standard phase difference of 90° can be generated. Specifically, this includes: Step S310: Compress the peak values ​​of the input n-45° head, n° head, and n+45° head sine signals; Step S320: Connect the reference encoder via coaxial or high-precision gear, and use a feasible error acquisition method to check the phase error of S0. If there is no phase difference, proceed to step S330; if the phase is lagging, proceed to step S340; if the phase is leading, proceed to step S350. Step S330: Turn off the analog switches at the back end of the input amplifiers of the n-45° head and the n+45° head, so that the 0° head signal is directly sent to the adder operational amplifier, and then the amplitude modulation and zeroing circuit is used to restore its peak value. Step S340 includes: 1) Enable the analog switch at the back end of the n-45° head input amplifier so that the output signal of this channel participates in phase subdivision together with the 0° head signal, obtaining ((θ n-45 +θ n ) / 2)+θ n The initial phase signal is 1 / 2, and then the signal amplitude is compressed. 2) Select a single or multiple initial phase signals based on the difference in phase lag; 3) Integrate the selected single or multiple initial phase signals with the 0° head signal, and then output them after amplitude modulation and zeroing; Step S350 includes: 1) Enable the analog switch at the back end of the n+45° head input amplifier, so that the output signal of this channel participates in phase subdivision together with the 0° head signal, to obtain ((θ n+45 +θ n ) / 2)+θ n The initial phase signal is 1 / 2, and then the signal amplitude is compressed. 2) Select a single or multiple initial phase signals based on the difference in phase lag; 3) Integrate the selected single or multiple initial phase signals with the 0° head signal, and then output them after amplitude modulation and zeroing.

2. The error correction method for an eccentric disc shaft angle encoder according to claim 1, characterized in that, It also includes a constant current control method for LEDs, specifically: The reference voltage module on the LED control board outputs a reference voltage to the comparator. The comparator compares the reference voltage with the sampling voltage fed back by the sampling resistor and then provides an adjusted output voltage to the power transistor. The output current of the power transistor is adjusted according to the change of the input voltage. This current flows through the power transistor, the LED, and the sampling resistor, generating a new sampling voltage on the sampling resistor, which is then fed back to the comparator to form constant current control of the LED.

3. The error correction method for an eccentric disc shaft angle encoder according to claim 1, characterized in that, The rear cover contains a bottom housing bearing collar, within which a bottom housing bearing is installed. The outer shaft surface of the bottom housing bearing is tightly fitted to the bottom housing bearing collar, and the inner shaft surface of the bottom housing bearing is tightly fitted to the main shaft of the encoder core. The rear cover has a first threaded hole. The encoder core comprises, in sequence, a light-emitting diode control board, a light-emitting diode holder, an eccentric disk, a receiver diode holder, and a receiver diode control board. A light-emitting diode is mounted on the light-emitting diode control board, and the light-emitting diode is coaxially assembled with the light-emitting diode holder's light-transmitting hole. The inner diameter of the light-transmitting hole is adapted to the outer diameter of the light-emitting diode. The receiver diode control board is provided with... The device includes a receiving tube, which is coaxially assembled with the light-transmitting hole of the receiving tube lamp holder. The inner diameter of the light-transmitting hole of the receiving tube lamp holder is adapted to the outer diameter of the receiving tube. The axial end faces of the light-emitting tube lamp holder and the receiving tube lamp holder are coincident and coaxially assembled with the eccentric disk, and are respectively located on both sides of the eccentric disk. A panel bearing collar is provided inside the mounting panel, and a panel bearing is coaxially assembled with the panel bearing collar. The panel bearing is coaxially installed with the bearing spindle of the eccentric disk. The bearing spindle of the eccentric disk passes through the core part of the encoder and is coaxially connected with the bottom shell bearing. The mounting panel is provided with a second threaded hole corresponding to the first threaded hole.

4. The error correction method for an eccentric disc shaft angle encoder according to claim 3, characterized in that, The diameter of the eccentric disk is the same as the diameter of the center of the eight light-transmitting holes of the light-emitting tube holder and the light-receiving tube holder. The eccentric distance of the eccentric disk is slightly smaller than the radius of the light-transmitting holes on the light-emitting tube holder and the light-receiving tube holder. When the eccentric disk rotates, the area of ​​the corresponding light-transmitting hole blocked by the eccentric disk changes.

5. The error correction method for an eccentric disc shaft angle encoder according to claim 3, characterized in that, A positioning strip is provided on the outer side of the bearing collar of the bottom shell, and a positioning groove is provided on the outer side of the encoder core part to fit tightly with the positioning strip.

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