Interference torque estimation and compensation method for an elevator system

Abstract

A method for estimating and compensating interference torque in a lifting system is applied to the motor driving the lifting system. The estimation and compensation method includes: First, controlling the car's movement up and down between the top and bottom of the shaft from its initial position, continuously integrating the motor speed. If the integral value obtained from the speed calculation is negative, the integral value is set to zero to obtain the maximum travel position of the car within the shaft. When the motor is running at a constant speed, the cable load constant is estimated based on the initial position and the maximum travel position, and the cable load torque is calculated based on the maximum travel position, the cable load constant, and the current position of the motor. When the motor is running at zero speed, the load torque of the car and counterweight is estimated based on the weight of the car and the counterweight. Based on the cable load torque and the load torque of the car and counterweight, the interference torque is estimated, and feedforward compensation is performed on the motor based on the interference torque.

Description

Technical Field

[0001] This invention relates to a method for estimating and compensating interference torque in a lifting system, and more particularly to a method for estimating and compensating interference torque in a lifting system based on the load torque of the steel cable and the load torque of the carriage and counterweight, and for feeding forward compensation of the motor based on the interference torque. Background Technology

[0002] Electric motors (such as motors) paired with frequency converters are widely used in lifting systems such as elevators, overhead cranes, and warehouses. To improve the performance of the drive system, a speed controller is typically designed using the system's relevant mechanical parameters to meet operational performance requirements.

[0003] Taking an elevator system as an example, the length of the steel cable varies depending on the floor the elevator car is on. This change in cable length during elevator movement generates varying disturbance torque for the controller, affecting control performance and ride comfort.

[0004] Therefore, how to design a method for estimating and compensating the interference torque of a lifting system, especially a method for estimating the interference torque based on the load torque of the steel cable and the load torque of the carriage and counterweight, and for feeding forward compensation of the motor based on the interference torque, is an important research topic for the inventors of this case, in order to solve the problems and technical bottlenecks existing in the prior art. Summary of the Invention

[0005] One objective of this invention is to provide a method for estimating and compensating for interference torque in a lifting system, thereby solving the problems of the prior art.

[0006] To achieve the aforementioned objectives, the proposed method for estimating and compensating the disturbance torque of a lifting system is applied to the motor driving the lifting system. The motor drives a traction sheave, causing it to rotate. Steel cables connect both ends of the traction sheave to move the car body up and down within the shaft. The estimation and compensation method includes: First, controlling the car body's movement up and down between the top and bottom of the shaft from its initial position, continuously integrating the motor speed. If the integral value obtained from the speed calculation is negative, the integral value is set to zero to obtain the maximum travel position of the car body within the shaft. Then, when the motor is running at a constant speed, the cable load constant is estimated based on the initial position and the maximum travel position. The cable load torque relative to the motor is calculated based on the maximum travel position, the cable load constant, and the current position of the motor. Finally, when the motor is running at zero speed, the load torque of the car body and the counterweight relative to the motor's load torque is estimated. Finally, based on the load torque of the steel cable and the load torque of the carriage and counterweight, the relative disturbance torque of the motor is estimated, and the motor is fed forward compensated based on the disturbance torque.

[0007] In one embodiment, the step of obtaining the maximum travel position of the shaft includes: continuously calculating the integral value as the car moves from the starting position to the top; if the integral value obtained by calculating the speed is negative, then specifying the integral value as zero; after the car moves to the top, then controlling the car to move in the opposite direction to the bottom while continuously calculating the integral value, and when the car moves to the bottom, the integral value obtained by calculating the speed has a maximum value, which is the maximum travel position.

[0008] In one embodiment, the step of obtaining the maximum travel position of the shaft includes: continuously calculating and updating the integral value of the speed as the car moves from the starting position to the bottom; after the car moves to the bottom, then controlling the car to move in the opposite direction to the top, continuously calculating the integral value; if the integral value of the calculated speed is negative, then specifying the integral value as zero; after the car moves to the top, then controlling the car to move in the opposite direction to the bottom, and when the car moves to the bottom, the integral value of the calculated speed has a maximum value, which is the maximum travel position.

[0009] In one embodiment, the step of feedforward compensation of the motor based on the disturbance torque includes: estimating the disturbance torque based on the load torque of the steel cable and the load torque of the carriage and counterweight; calculating the compensation torque for feedforward compensation of the motor based on the disturbance torque; and completing the feedforward compensation within a time interval under zero-speed control based on the compensation torque.

[0010] In one embodiment, the time interval is the difference between the current time and the release time of the lifting system. The step of completing the feedforward compensation within the time interval includes: calculating the slope of the compensation current based on the compensation torque and the time interval, and completing the feedforward compensation of the compensation torque within the time interval based on the slope of the compensation current.

[0011] In one embodiment, the disturbance torque is estimated when the carriage is empty.

[0012] In one embodiment, the carriage also includes a weight sensor to sense the passenger load torque generated by the passenger's weight, and to estimate the relative disturbance torque of the motor based on the cable load torque, the carriage and counterweight load torque and the passenger load torque.

[0013] Another objective of this invention is to provide a method for estimating and compensating for interference torque in a lifting system, thereby addressing the problems of the prior art.

[0014] To achieve the aforementioned objectives, the proposed method for estimating and compensating the disturbance torque of a lifting system is applied to the motor driving the lifting system. The motor drives a traction sheave, causing it to rotate. Steel cables connect both ends of the traction sheave to move the car body up and down within the shaft. The estimation and compensation method includes: First, while controlling the car body's movement up and down between the top and bottom of the shaft from its initial position, the motor speed is continuously integrated. If the integral value obtained from the speed calculation is negative, the absolute value of the integral value is calculated to obtain the maximum travel position of the car body within the shaft. Then, when the motor is running at a constant speed, the cable load constant is estimated based on the initial position and the maximum travel position. The cable load torque relative to the motor is calculated based on the maximum travel position, the cable load constant, and the current position of the motor. Finally, when the motor is running at zero speed, the load torque of the car body and the counterweight relative to the motor is estimated. Finally, based on the load torque of the steel cable and the load torque of the carriage and counterweight, the relative disturbance torque of the motor is estimated, and the motor is fed forward compensated based on the disturbance torque.

[0015] In one embodiment, the step of obtaining the maximum travel position of the hoistway includes: continuously calculating the integral value as the car moves from the starting position to the top; if the integral value obtained by calculating the speed is negative, then performing an absolute value operation on the integral value; when the car moves to the top, the integral value is recorded as the upward position; then controlling the car to move in the opposite direction; when the car moves past the starting position again, continuously calculating and updating the integral value obtained by the speed until the car moves to the bottom, then recording the integral value as the downward position; and calculating the maximum travel position by summing the upward and downward positions.

[0016] In one embodiment, the step of obtaining the maximum travel position of the shaft includes: continuously calculating and updating the integral value of the speed as the car moves from the starting position to the bottom; when the car reaches the bottom, the integral value is recorded as the downward position; then controlling the car to move in the opposite direction; when the car moves past the starting position again, continuously calculating and updating the integral value of the speed; if the integral value of the calculated speed is negative, the integral value is calculated as an absolute value until the car reaches the top, at which point the integral value is recorded as the upward position; and calculating the maximum travel position by summing the upward and downward positions.

[0017] Based on the proposed method for estimating and compensating the disturbance torque of the lifting system, different load torque estimators are designed, including: (a) car floor estimation, (b) cable load constant estimation for estimating the unbalanced load torque on both sides of the cable traction, and (c) car and counterweight weight imbalance load torque estimation. Torque estimation can be performed before the car brakes are released and during the movement of the cable, where the rope length on both sides of the traction changes with the car height. Therefore, torque feedforward compensation can be directly performed during the movement through cable load estimation to reduce the impact of disturbance torque on the speed controller. Furthermore, feedforward torque compensation before brake release can effectively reduce the noise caused by the instantaneous change in current after brake release, effectively improving the ride comfort.

[0018] To gain a deeper understanding of the techniques, means, and effects employed by this invention to achieve its intended purpose, please refer to the following detailed description and accompanying drawings. It is believed that the purpose, features, and characteristics of this invention can be understood in a thorough and specific manner from these drawings. However, the drawings are provided for reference and illustration only and are not intended to limit the scope of this invention. Attached Figure Description

[0019] Figure 1A : This is a schematic diagram of the lifting system of the present invention;

[0020] Figure 1B This is a schematic diagram illustrating how the interference torque of the lifting system of the present invention changes with the position of the carriage.

[0021] Figure 2 : This is a block diagram of the first-order closed-loop speed control architecture of the present invention;

[0022] Figure 3A : This is a flowchart of the first embodiment of the interference torque estimation and compensation method for the lifting system of the present invention;

[0023] Figure 3B : This is a flowchart of the second embodiment of the interference torque estimation and compensation method for the lifting system of the present invention;

[0024] Figure 3C : This is a schematic diagram of the feedforward compensation method of the lifting system of the present invention;

[0025] Figure 4 : This is a block diagram of the first embodiment of the maximum travel position calculation of the present invention;

[0026] Figure 5 : A waveform diagram of the first embodiment of the first embodiment of the present invention for obtaining the maximum travel position;

[0027] Figure 6 : A waveform diagram illustrating a second embodiment of the first embodiment of the present invention for obtaining the maximum travel position;

[0028] Figure 7 : This is a block diagram of the second embodiment of the maximum travel position calculation of the present invention;

[0029] Figure 8 : This is a waveform diagram of the first embodiment of the second embodiment of the present invention for obtaining the maximum travel position;

[0030] Figure 9 : A waveform diagram illustrating a second embodiment of the second embodiment of the present invention for obtaining the maximum travel position;

[0031] Figure 10 : This is a block diagram of the motor drive system of the present invention.

[0032] Explanation of icon numbers:

[0033] 100: Carriage

[0034] 102: Traction Wheel

[0035] 104: Counterweight wheel

[0036] 106: Counterweight

[0037] 200: Shaft

[0038] T Mech Mechanical interference amount

[0039] S11~S14: Steps

[0040] S21~S24: Steps Detailed Implementation

[0041] The technical content and detailed description of the present invention are explained below with reference to the accompanying drawings.

[0042] Please see Figure 1A and Figure 1BThe figures shown are schematic diagrams of the lifting system of the present invention and schematic diagrams of the interference torque of the lifting system of the present invention changing with the position of the car. In this invention, an elevator system is used as an example of the lifting system, but this is not intended to limit the invention; a crane system could also be used. The elevator system mainly includes a car 100, a traction wheel 102, a counterweight wheel 104, and a counterweight 106, all installed in the hoistway 200. The traction wheel 102 is driven by a motor to rotate, causing the car 100 to move up and down within the hoistway 200 by a steel cable (or steel wire) suspended from the traction wheel 102. The two ends of the steel cable are mechanically connected to the car 100 and the counterweight 106, respectively. As the carriage 100 moves up and down at different floor levels, the lengths of the steel cables on both sides of the motor traction differ, resulting in different cable weights on both sides. This creates interference torque relative to the motor's operation. For example, when the carriage 100 is on a lower floor, the steel cable on the carriage 100 side is longer, meaning the load on that side is heavier; conversely, when the carriage 100 is on a higher floor, the steel cable on the counterweight 106 side is longer, thus the load on that side is heavier. Figure 1A As shown, for the motor driving the traction sheave 102, the car 100 is on the left and the counterweight 106 is on the right. The load on the motor from both remains constant over time. Only when the position of the car 100 within the hoistway 200 changes over time does the length of the steel cables on both sides of the traction sheave 102 change due to the change in height. This change in the weight of the steel cables on both sides of the traction sheave 102 and the resulting weight difference causes a change in the interference torque relative to the motor. For details, please refer to... Figure 1B From top to bottom, the figures show the counterweight load relative to the motor and the position θ of the carriage. a The relationship between the load on the carriage and the position θ of the carriage, and the relationship between the load on the steel cable and the position θ of the carriage. a The relationship between the total (interference) load and the car position θ a Therefore, the purpose of this invention is to determine the cable length relative to the estimated cable load torque of the motor based on the different floor positions of the carriage 100, and to estimate the load torque of the carriage and counterweight relative to the motor based on the weight difference between the carriage 100 and the counterweight 106. This allows for the estimation of the magnitude of the interference torque of the lifting system relative to the motor, and the provision of feedforward compensation to the motor based on the interference torque, i.e., compensation provided before the motor starts operating, so that the motor can start and operate more smoothly.

[0043] Please see Figure 2The diagram shown is a block diagram of the first-order closed-loop speed control architecture of the present invention. The closed-loop speed control architecture includes a speed controller to output a control quantity to control a controlled entity. In this embodiment, the controlled entity can be a motor, as illustrated by a first-order closed-loop control system. The torque output by the motor needs to overcome the mechanical disturbance T. Mech Then, the system control operation can be carried out. Therefore, if the mechanical disturbance T can be addressed first... Mech After estimation and compensation, the remaining load change represents the weight of passengers entering and exiting the elevator. In other words, the generalized mechanical disturbance T... Mech It may include the unbalanced torque of the steel cable, the load torque of the car 100, the load torque of the counterweight 106, and the disturbance torque relative to the motor caused by the weight of the passengers in the elevator. However, since the weight of the passengers in the car 100 is a variable that is either impossible or difficult to estimate, the disturbance torque caused by the fixed mechanical parts such as the steel cable, car 100, and counterweight 106 after the elevator system is built can be estimated and pre-compensated in advance to simplify subsequent control.

[0044] Please see Figure 3A This is a flowchart of the first embodiment of the interference torque estimation and compensation method for the lifting system of the present invention. The interference torque estimation and compensation method is applied to the motor driving the lifting system. The estimation and compensation method includes the following steps.

[0045] First, control the initial position θ of the car 100 within the shaft 200. a0 During the up-and-down movement between the top and bottom of the shaft 200, the speed ω fed back to the motor is... m Continue integrating, if the calculated speed ω m If the obtained integral value is negative, then the integral value is set to zero, in order to obtain the maximum travel position θ of the carriage 100 moving up and down within the hoistway 200. Max (S11). In other words, step (S11) is mainly used to obtain the maximum travel position θ of the shaft 200. Max The information. The first embodiment of the present invention proposes two specific implementation methods to obtain the maximum travel position θ. Max The information will be explained one by one later. Then, when controlling the motor to run at a constant speed, it is based on the initial position θ. a0 With maximum travel position θ Max The load constant of the steel cable is estimated, and based on the position of maximum stroke θ Max The cable load constant and the current position θ of the motor aCalculate the cable load torque relative to the motor (S12). Then, when controlling the motor to run at zero speed, estimate the load torque of the car body 100 and the counterweight 106 relative to the motor based on the weight of the car body 100 and the counterweight 106 (S13). Finally, estimate the disturbance torque relative to the motor based on the cable load torque and the load torque of the car body and counterweight, and perform feedforward compensation on the motor based on the disturbance torque (S14). Steps (S11) to (S14) will be explained in detail below with reference to the accompanying drawings.

[0046] In addition, such as Figure 3B The diagram shown is a flowchart of the second embodiment of the interference torque estimation and compensation method for the lifting system of the present invention. Compared to the first embodiment of the present invention (see...), Figure 3A The second embodiment differs from step S11 only in step S21; the remaining steps are the same. Specifically, step S21 in the second embodiment involves controlling the initial position θ of the carriage 100 within the shaft 200. a0 During the up-and-down movement between the top and bottom of the shaft 200, the speed ω fed back to the motor is... m Continue integrating, if the calculated speed ω m If the integral value is negative, the absolute value of the integral value is calculated to obtain the maximum travel position θ of the car 100 moving up and down within the shaft 200. Max (S21)

[0047] like Figure 3C The diagram illustrates the feedforward compensation method of the lifting system of this invention. Without feedforward compensation, a large current needs to be output instantaneously after the brake is released, resulting in a large current slope and generating electromagnetic noise. Conversely, if the compensation time is too late, such as after the brake is released, there will not be enough time to compensate for sufficient torque, causing the car to slip. Therefore, the feedforward compensation method of this invention is as follows: The interference torque is estimated based on the load torque of the steel cable and the load torque of the car and counterweight; then, the compensation torque for feedforward compensation of the motor is calculated based on the interference torque (approximately completed between time t1 and t2); and the feedforward compensation is completed within the time interval under zero-speed control based on the compensation torque (approximately completed between time t2 and t3). Specifically, the compensation current slope is calculated based on the compensation torque and the time interval, and the current is compensated within the time interval based on the compensation current slope to complete the feedforward compensation of the compensation torque. The time interval is the difference between the current time and the brake release time of the lifting system. The above method ensures that the torque feedforward compensation is not completed instantaneously before the brake release or too late after the brake release, and the application of the compensation current is planned to be gradual, which can reduce noise and prevent runaway.

[0048] As mentioned above, since this invention uses a frequency converter for motor control, but the frequency converter cannot obtain information about the floor where the carriage 100 is located, it can only estimate the maximum travel position θ of the carriage 100 through information such as the length (distance) of the shaft 200 and the motor speed. Max Furthermore, because the load torque generated by the difference in length on both sides of the steel cable is related to the position of the carriage, the inverter of a general control method cannot know the actual position of the carriage. Therefore, before estimating and compensating for the load torque of the steel cable, the position of the carriage 100 must be estimated first.

[0049] Without considering cable slippage, the distance the carriage 100 moves is the same as the angle of rotation of the motor traction. Therefore, by integrating the motor speed, the estimated position of the carriage 100 can be obtained, expressed as equation (1):

[0050] ∫ω m dt=θ a +θ a0 Equation (1)

[0051] Where, θ a The current position of carriage 100, θ a0 The initial position (or starting position) of the carriage is 100, ω m The current speed of the motor is given. Therefore, by integrating the motor speed using equation (1), the estimated position of the carriage 100 can be obtained. Thus, it is not necessary to know the parameter values ​​of the mechanical equipment (such as the diameter of the traction sheave 102, the diameter of the counterweight sheave 104, etc.), and the calculation of the conversion from circular motion to linear motion can be omitted.

[0052] The following section addresses step (S11), which involves obtaining the maximum travel position θ of the carriage 100 within the shaft 200. Max Different embodiments are described below.

[0053] First embodiment of the first embodiment

[0054] See also Figure 4 and Figure 5 These are, respectively, a block diagram of the first embodiment of the maximum travel position calculation of the present invention and a waveform diagram of the first implementation of the first embodiment of obtaining the maximum travel position, and please refer to... Figure 3A Step (S11) may include the following detailed steps: when the carriage 100 moves from the starting position θ a0 During the movement to the top of shaft 200, if the motor speed ω is calculated in real time... m If the obtained integral value is negative, then the integral value is set to zero, and the integral value is continuously calculated based on the motor speed during the movement of the carriage 100.

[0055] Then, after the carriage 100 moves to the top, it is controlled to move in the opposite direction to the bottom of the shaft 200, and the motor speed ω is calculated when the carriage 100 moves to the bottom. m The obtained integral value has a maximum value, which is the maximum travel position θ of the carriage 100 moving up and down in the shaft 200. Max .

[0056] Therefore, since the maximum travel distance of the car 100 within the shaft 200 is fixed, the integral of the motor speed for one round trip between the top and bottom floors must be zero. Utilizing this characteristic, when the calculated integral value is less than zero, that integral value is cleared (i.e., the integral value is specified as zero). In this way, by simply making one round trip between the top and bottom floors, the distance between the car 100's location and the top of the shaft 200 can be eliminated, and the actual starting position θ of the car 100 can be obtained. a0 and the maximum travel position θ Max .

[0057] like Figure 5 As shown, in this embodiment, the first interval for calculation (i.e., floors 3 to 6 in the attached diagram) starts at position θ. a0 On the 3rd floor, not the actual top floor (6th floor) of shaft 200, the carriage 100 is moved from its starting position θ. a0 When moving upwards to the top floor (i.e., from floor 3 to floor 6 in the attached diagram), because carriage 100 continuously moves upwards, the integral value of the motor speed is always less than zero (negative). Therefore, the obtained integral value is continuously forcibly set (specified) to zero to update the actual zero point of the calculated travel distance. In the second interval of the calculation (i.e., from floor 6 to floor 1 in the attached diagram), it can be seen that when carriage 100 moves downwards from the top floor to the bottom floor, the integral value of the motor speed is always greater than zero, and the maximum travel position θ... Max As carriage 100 moves from the 6th floor to the 1st floor, its maximum value is continuously updated. Once the calculation for the second interval is completed, the relative angle of the motor and the maximum distance traveled by the motor during the movement of carriage 100 can be estimated. That is, when carriage 100 reaches the 1st floor, the maximum value of the updated integral of the motor speed is the maximum travel position θ. Max .

[0058] Second implementation of the first embodiment

[0059] See also Figure 4 and Figure 6 These are, respectively, a block diagram of the first embodiment of the maximum travel position calculation of the present invention and a waveform diagram of the second embodiment of the first embodiment of obtaining the maximum travel position, and please refer to... Figure 3B Step (S11) may include the following detailed steps: when the carriage 100 moves from the starting position θ a0During the movement towards the bottom of the shaft 200, the motor speed ω is continuously calculated and updated. m The obtained integral value.

[0060] Then, after the carriage 100 moves to the bottom, it is controlled to move in the opposite direction to the top of the shaft 200. The motor speed ω is calculated in real time. m If the obtained integral value is negative, then the integral value is set to zero, and the integral value is continuously calculated based on the motor speed during the movement of the carriage 100.

[0061] Then, after the carriage 100 moves to the top, it is controlled to move back to the bottom, and the motor speed ω is calculated when the carriage 100 moves to the bottom. m The obtained integral value has a maximum value, which is the maximum travel position θ. Max .

[0062] Therefore, since the maximum travel distance of car 100 within the shaft 200 is fixed, the speed integral for one round trip between the top and bottom floors must be zero. Utilizing this characteristic, when the integral value is less than zero, it is cleared (i.e., the integral value is set to zero). In this way, by simply making one round trip between the top and bottom floors, the distance between car 100 and the top of the shaft 200 can be eliminated, and the actual starting position θ of car 100 can be obtained. a0 and the maximum travel position θ Max .

[0063] like Figure 6 As shown, in this embodiment, the first interval for calculation (i.e., the process from the 4th floor to the 1st floor in the attached diagram) starts at position θ. a0 On the 4th floor, not the actual top floor of hoistway 200 (6th floor), when moving car 100 to the 1st floor, integrating the motor speed yields the estimated position for that travel segment, and simultaneously updates the maximum position value. In the second calculation interval (i.e., the process from the 1st to the 6th floor in the attached diagram), it can be seen that when the integral value of the motor speed is less than zero (negative), the integral value is forcibly set (specified) to zero to eliminate the distance θ between the current position of car 100 and the top of hoistway 200. a In the third interval of the calculation (i.e., the process from floor 6 to floor 1 in the attached diagram), the shaft travels from the actual top floor (floor 6) down to the bottom floor (floor 1) in shaft 200. During this process, the velocity integral is always greater than zero, and the maximum travel position θ... Max As carriage 100 moves from the 6th floor to the 1st floor and continuously updates its maximum value, the relative angle of the motor and the maximum distance traveled by carriage 100 during its movement can be estimated. That is, when carriage 100 reaches the 1st floor, the maximum value of the updated motor speed integral is the maximum travel position θ. Max .

[0064] The first embodiment of the second example

[0065] See also Figure 7 and Figure 8 These are, respectively, a block diagram of the second embodiment of the maximum travel position calculation of the present invention and a waveform diagram of the first embodiment of the second embodiment of obtaining the maximum travel position, and please refer to... Figure 3B Step (S21) may include the following detailed steps: when the carriage 100 moves from the starting position θ a0 During the movement to the top of shaft 200, if the motor speed ω is calculated... m If the obtained integral value is negative, the absolute value of the integral value is calculated and continuously updated. When carriage 100 moves to the top, the integral value corresponding to this journey is recorded as the upward position θ. MAX_u Incidentally, Figure 7 The block diagram shown also includes the calculations of specifying the integral value as zero and the maximum value as the maximum travel position in the first and second implementations of the first embodiment described above.

[0066] Next, control the carriage 100 to move in the opposite direction. When the carriage 100 moves and passes the starting position θ again... a0 At that time, the motor speed ω is continuously calculated and updated. m The obtained integral value is recorded as the integral value corresponding to the downward position θ after the carriage 100 moves to the bottom. MAX_d Then, based on the uplink position θ MAX_u With the downlink position θ MAX_d To obtain the maximum total travel position θ Max .

[0067] like Figure 8 As shown, in this embodiment, the first interval calculated (i.e., the process from the 3rd to the 6th floor in the attached diagram) has a starting position θ for carriage 100. a0 On the 3rd floor, which is not the actual top floor of shaft 200 (6th floor), when moving car 100 to the top floor, because the integral value of the motor speed is always less than zero (negative value), the starting position θ is forcibly set (specified). a0 If the integral is zero, record the values ​​less than zero and process them to obtain the distance θ between the location of car 100 and the top of shaft 200. a The maximum travel position θ can be corrected immediately. Max In the second interval of the calculation (i.e., the process from the 6th floor to the 1st floor in the attached diagram), it can be seen that when carriage 100 moves downwards from the top floor, the integral of the motor speed is always greater than zero, and the maximum travel position θ... Max As carriage 100 moves from the 6th floor to the 1st floor and continuously updates its maximum value, the relative angle of the motor and the maximum distance traveled by carriage 100 during movement can be estimated. It should be noted that the calculation method in this embodiment starts at position θ. a0Position greater than the maximum travel θ Max At that time, correct the maximum travel position θ Max .

[0068] The second embodiment of the second implementation

[0069] See also Figure 7 and Figure 9 These are, respectively, a block diagram of the second embodiment of the maximum travel position calculation of the present invention and a waveform diagram of the second implementation of the second embodiment of the present invention for obtaining the maximum travel position, and please refer to... Figure 3B Step (S21) may include the following detailed steps: when the carriage 100 moves from the starting position θ a0 During the movement towards the bottom of the shaft 200, the motor speed ω is continuously calculated and updated. m The obtained integral value is recorded as the integral value corresponding to the downward position θ after the carriage 100 moves to the bottom. MAX_d .

[0070] Next, control the carriage 100 to move in the opposite direction. When the carriage 100 moves and passes the starting position θ again... a0 At that time, the motor speed ω is continuously calculated and updated. m The obtained integral value, and if the motor speed ω is calculated... m If the obtained integral value is negative, the absolute value of the integral value is calculated and the integral value is continuously updated until the carriage 100 moves to the top. At this point, the integral value corresponding to this journey is recorded as the upward position θ. MAX_u Then, based on the uplink position θ MAX_u With the downlink position θ MAX_d To obtain the maximum total travel position θ Max .

[0071] like Figure 9 As shown, in this embodiment, the first interval for calculation (i.e., the process from the 4th floor to the 1st floor in the attached diagram) starts at position θ. a0 On the 4th floor, which is not the actual top floor of shaft 200 (6th floor), when moving car 100 to the 1st floor, the estimated starting position θ can be obtained by integrating the motor speed. a0 Simultaneously update the maximum travel position θ. Max In the second interval of the calculation (i.e., the process from floor 1 to floor 6 in the attached diagram), it can be seen that when the velocity integral value is less than zero (negative), the initial position θ is forcibly set (specified). a0 By setting the integral to zero and recording and processing the values ​​less than zero, the distance θ between the location of car 100 and the top of shaft 200 can be calculated. a It can instantly correct the maximum travel position θ Max That is, when carriage 100 reaches the 6th floor, the updated maximum value is the maximum travel position θ.Max .

[0072] Furthermore, for step (S12) or step (S22), that is, when controlling the motor to run at a constant speed, based on the initial position θ a0 With maximum travel position θ max The specific explanation for estimating the load constant of the steel cable is as follows.

[0073] The equation of motion for a motor considering the change in cable length can be expressed as equation (2):

[0074]

[0075] Among them, J m For rotational inertia, T e For motor output torque, T p The load torque generated for passengers, T c The load torque generated by the carriage body, T rc and T rw These represent the load torque and T generated by the changes in the steel cables on the car side and the counterweight side, respectively. w The load torque generated by the counterweight, B m It is the coefficient of viscous friction.

[0076] The load on the steel cable is related to the position of the carriage, as expressed by equations (3a) and (3b):

[0077] T rc =K r θ a Equation (3a)

[0078] T rw =K r (θ Max -θ a Equation (3b)

[0079] Where Kr is the cable load constant.

[0080] Substituting equations (3a) and (3b) into equation (2), we get:

[0081]

[0082] After simplification, we get:

[0083]

[0084] Since step (S12) or step (S22) involves estimating the interference torque of the steel cable relative to both sides of the motor traction when the motor is running at a constant speed, equation (5) can be rewritten as:

[0085] 0 = T e +Tp +T c +K r (2θ a -θ Max )-T w -B m ω m Equation (6)

[0086] After rearranging and simplifying, the motor output torque can be obtained as follows:

[0087] T e =-T p -T c -K r (2θ a -θ Max )+T w +B m ω m Equation (7)

[0088] Next, differentiating the output torque with respect to the angle, we get:

[0089]

[0090] After rearranging the above formula, the cable load constant can be obtained as:

[0091]

[0092] Furthermore, for step (S13) or step (S23), i.e., when controlling the motor to run at zero speed, the load torque of the car body and counterweight relative to the motor's car body and counterweight is estimated based on the weight of the car body and the weight of the counterweight; and for step (S14) or step (S24), i.e., based on the maximum stroke position θ... max The following is a detailed explanation of the interference torque relative to the motor, which is estimated by the cable load constant and the load torque of the carriage and counterweight, and the feedforward compensation of the motor based on the interference torque.

[0093] Using equation (5) to consider the change in cable length, the torque equation is as follows:

[0094]

[0095] Where T c With T w The sum is the load torque of the car body and counterweight, K r (2θ a -θ Max This refers to the load torque of the steel cable; while in an empty car (without passengers, i.e., T... p =0), when performing zero-speed motor control, it is no longer necessary to estimate the disturbance torque caused by the relative weight of the passengers to the motor. Equation (10) can be simplified and rewritten as:

[0096] 0 = T e +T c +K r (2θ a -θ Max )-T w Equation (11)

[0097] After rearranging and simplifying, the total load torque of the car body and counterweight can be obtained as follows:

[0098] T c -T w =-T e -K r (2θ a -θ Max Equation (12)

[0099] Therefore, the estimation of the carriage position using equation (1) can be expressed as:

[0100]

[0101] The load constant of the steel cable can be estimated using equation (9) as follows:

[0102]

[0103] The summation of the load torque of the car body and counterweight using equation (12) is expressed as follows:

[0104]

[0105] In one embodiment, the torque feedforward compensation before gate release is set as follows:

[0106]

[0107] The total torque command can be expressed as:

[0108]

[0109] For the calculation of the feedforward compensation amount, equation (17) can be found in the reference section. Figure 10 A partial block diagram in the upper left corner. Torque control is performed using the total torque command of equation (17) (i.e., setting T). e =T e * ), and calculate T e Substituting equation (2) into the system's equation of motion, we can express it as:

[0110]

[0111] When the estimated value is very close to the actual value, equation (18) can be simplified to:

[0112]

[0113] In another embodiment, if the carriage has a load cell, the weight of the passengers in the carriage 100 can be accurately estimated, and the passenger load torque generated by the passenger weight relative to the motor can be calculated. Then, equation (16) for torque feedforward compensation before brake release can be rewritten as:

[0114]

[0115] The total torque command can be expressed as:

[0116]

[0117] When the estimated value is very close to the actual value, the above formula can be simplified to:

[0118]

[0119] Please see Figure 10 The diagram shown is a block diagram of the motor drive system of the present invention, including the architecture of the hardware and firmware (or software) required for motor drive. The motor drive system includes outer loop control (i.e., speed control, used to control the motor's rotational speed) and inner loop control (i.e., current control, used to control the motor's torque value). In the outer loop control, the speed controller receives the speed command ω. m * This means that a command is received to control the speed (corresponding to the motor speed) of the carriage 100. Combined with position feedback information from the position sensor, the actual speed of the carriage 100 (i.e., the actual motor speed) is calculated by the speed calculator and fed back to the speed controller. Therefore, according to the speed command ω... m * With speed feedback, a current command, i.e. an equivalent torque command, can be obtained.

[0120] The current controller receives current commands and current feedback from the sensed current measured by the current sensor in the inner loop control circuit (the sensed current is converted into current feedback by a current converter, which can convert the three-phase stationary coordinates abc to the synchronous rotating coordinates dq), and generates a voltage command. The voltage command is modulated by a PWM modulator to generate a gate signal, which then controls the inverter (or frequency converter) to drive the motor.

[0121] Therefore, this invention provides different load torque estimators, including: (a) a car floor estimation, (b) a cable load constant estimation for estimating unbalanced load torque on both sides of the cable traction, and (c) a car and counterweight weight imbalance load torque estimation. Since the cable changes with height before the car brakes are released and during travel, torque feedforward compensation can be performed directly during travel via cable load estimation to reduce the impact of disturbance torque on the speed controller. Furthermore, feedforward torque compensation before brake release can effectively reduce noise caused by instantaneous current changes after brake release, effectively improving ride comfort.

[0122] The above description is merely a detailed description and accompanying drawings of preferred embodiments of the present invention. The features of the present invention are not limited thereto and are not intended to limit the present invention. The scope of the present invention should be determined by the following claims. All embodiments that conform to the spirit of the claims of the present invention and similar variations thereof should be included in the scope of the present invention. Any variations or modifications that can be easily conceived by those skilled in the art within the field of the present invention can be covered by the following patent scope.

Claims

1. A method for estimating and compensating for interference torque in a lifting system, applied to a motor driving a lifting system, wherein the motor drives a traction sheave to rotate, and steel cables are connected at both ends of the traction sheave to move a car body up and down within a shaft; the method for estimating and compensating for interference torque includes: Step (a): Controlling the car to move up and down between the top and bottom of the shaft from its starting position in the shaft, continuously integrating the speed of the motor. If the integral value of the calculated speed is negative, then specify the integral value as zero, so as to obtain the maximum travel position of the car moving up and down in the shaft. Step (b): When controlling the motor to run at a constant speed, the cable load constant of the steel cable is estimated based on the starting position and the maximum stroke position, and the cable load torque of the steel cable relative to the motor is calculated based on the maximum stroke position, the cable load constant and the current position of the motor. Step (c), when controlling the motor to run at zero speed, estimate the load torque of the motor relative to the weight of the carriage and the counterweight block, based on the weight of the carriage and the weight of the counterweight block; and Step (d): Based on the load torque of the steel cable and the load torque of the carriage and counterweight, estimate the interference torque relative to the motor, and perform feedforward compensation on the motor based on the interference torque.

2. The method for estimating and compensating interference torque according to claim 1, wherein step (a) comprises: Step (a1): As the carriage moves from the starting position to the top, the integral value is continuously calculated. If the integral value obtained from calculating the speed is negative, then the integral value is set to zero; and Step (a2): After the carriage moves to the top, the carriage is then controlled to move in the opposite direction to the bottom. During the movement, the integral value is continuously calculated, and the integral value obtained by calculating the speed when the carriage moves to the bottom has a maximum value. The maximum value is the maximum travel position.

3. The method for estimating and compensating interference torque according to claim 1, wherein step (a) comprises: Step (a1): As the carriage moves from the starting position to the bottom, the integral value obtained from the speed is continuously calculated and updated; Step (a2): After the carriage moves to the bottom, the carriage is then controlled to move in the opposite direction to the top. During the movement, the integral value is continuously calculated. If the integral value obtained from calculating the speed is negative, then the integral value is set to zero. Step (a3): After the carriage moves to the top, the carriage is then controlled to move in the opposite direction to the bottom. During the movement, the integral value is continuously calculated, and the integral value obtained by calculating the speed when the carriage moves to the bottom has a maximum value. The maximum value is the maximum travel position.

4. The method for estimating and compensating interference torque according to claim 1, wherein step (d) comprises: Step (d1): Estimate the disturbance torque based on the load torque of the steel cable and the load torque of the carriage and counterweight. Step (d2): Calculate the compensation torque for feedforward compensation of the motor based on the disturbance torque; and Step (d3): Based on the compensation torque under the zero-speed control, feedforward compensation is completed within the time interval.

5. The interference torque estimation and compensation method according to claim 4, wherein the time interval is the difference between the current time and the release time of the lifting system, and step (d3) calculates the compensation current slope based on the compensation torque and the time interval, and completes the feedforward compensation of the compensation torque in the time interval based on the compensation current slope.

6. The method for estimating and compensating interference torque according to claim 1, wherein step (d) is performed when the carriage is empty.

7. The interference torque estimation and compensation method according to claim 1, wherein the carriage further includes a weight sensor for sensing the passenger load torque generated by the passenger's weight, wherein step (d) estimates the interference torque relative to the motor based on the cable load torque, the carriage and counterweight load torque and the passenger load torque.

8. A method for estimating and compensating for interference torque in a lifting system, applied to a motor driving the lifting system, wherein the motor drives a traction sheave to rotate, and steel cables are connected at both ends of the traction sheave to move a car body up and down within a shaft; the method for estimating and compensating for interference torque includes: Step (a): Controlling the car to move up and down between the top and bottom of the shaft from its starting position in the shaft, continuously integrating the speed of the motor. If the integral value of the calculated speed is negative, then perform an absolute value operation on the integral value to obtain the maximum travel position of the car moving up and down in the shaft. Step (b): When controlling the motor to run at a constant speed, the cable load constant of the steel cable is estimated based on the starting position and the maximum stroke position, and the cable load torque of the steel cable relative to the motor is calculated based on the maximum stroke position, the cable load constant and the current position of the motor. Step (c), when controlling the motor to run at zero speed, estimate the load torque of the motor relative to the weight of the carriage and the counterweight block, based on the weight of the carriage and the weight of the counterweight block; and Step (d): Based on the load torque of the steel cable and the load torque of the carriage and counterweight, estimate the interference torque relative to the motor, and perform feedforward compensation on the motor based on the interference torque.

9. The method for estimating and compensating disturbance torque according to claim 8, wherein step (a) comprises: Step (a1): As the carriage moves from the starting position to the top, the integral value is continuously calculated and updated. If the integral value obtained by calculating the speed is negative, the absolute value of the integral value is calculated. After the carriage moves to the top, the integral value is recorded as the upward position. Step (a2): Next, control the carriage to move in the opposite direction. When the carriage passes the starting position again, start continuously calculating and updating the integral value obtained from the speed until the carriage moves to the bottom, then record the integral value as the downward position; and Step (a3): Calculate the maximum travel position by summing the up position and the down position.

10. The method for estimating and compensating disturbance torque according to claim 8, wherein step (a) comprises: Step (a1): As the carriage moves from the starting position to the bottom, the integral value obtained by the speed is continuously calculated and updated. When the carriage moves to the bottom, the integral value is recorded as the downward position. Step (a2): Next, control the carriage to move in the reverse direction. When the carriage passes the starting position again, start continuously calculating and updating the integral value obtained from the speed. If the integral value obtained from the speed calculation is negative, perform an absolute value operation on the integral value until the carriage moves to the top, then record the integral value as the upward position; and Step (a3): Calculate the maximum travel position by summing the up position and the down position.

11. The method for estimating and compensating disturbance torque according to claim 8, wherein step (d) comprises: Step (d1): Estimate the disturbance torque based on the load torque of the steel cable and the load torque of the carriage and counterweight. Step (d2): Calculate the compensation torque for feedforward compensation of the motor based on the disturbance torque; and Step (d3): Based on the compensation torque under the zero-speed control, feedforward compensation is completed within the time interval.

12. The interference torque estimation and compensation method according to claim 11, wherein the time interval is the difference between the current time and the release time of the lifting system, and step (d3) calculates the compensation current slope based on the compensation torque and the time interval, and completes the feedforward compensation of the compensation torque based on the compensation current slope in the time interval.

13. The method for estimating and compensating interference torque according to claim 8, wherein step (d) is performed when the carriage is empty.

14. The interference torque estimation and compensation method according to claim 8, wherein the carriage further includes a weight sensor for sensing the passenger load torque generated by the passenger's weight, wherein step (d) estimates the interference torque relative to the motor based on the cable load torque, the carriage and counterweight load torque and the passenger load torque.

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