Method for operating a vehicle, and vehicle
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- SEW EURODRIVE GMBH & CO KG
- Filing Date
- 2024-05-29
- Publication Date
- 2026-04-29
AI Technical Summary
Existing vehicle operation methods fail to reliably prevent mechanical overload and ensure secure operation, particularly when transporting loads at different heights, as they do not effectively regulate bending forces within critical limits.
The method involves a dual-drive system with field-oriented control, where the first drive and second drive adjust their speed setpoints to maintain a target speed while regulating the bending setpoint by calculating torque values, ensuring the bending remains below a critical value through a PI controller and coupling factor, and utilizing sensors to monitor actual bending values.
This approach enhances reliability and security by preventing overloading and maintaining bending within safe limits, allowing for efficient power usage and long service life by transferring feed force between drives, even when cornering or changing load positions.
Smart Images
Figure EP2024064730_26122024_PF_FP_ABST
Abstract
Description
[0001] Method for operating a vehicle and vehicle
[0002] Description:
[0003] The invention relates to a method for operating a vehicle and a vehicle.
[0004] It is common knowledge that a load can be transported by a vehicle, especially at different heights.
[0005] From DE 102010 020 124 A1, a method for operating a vehicle is known as the closest prior art.
[0006] A control device for the drive torques of locomotive wheel axles is known from E 36678 B.
[0007] The invention is therefore based on the object of ensuring reliable operation of a vehicle.
[0008] According to the invention, the object is achieved in the method for operating a vehicle according to the features specified in claim 1 and in the vehicle according to the features specified in claim 13.
[0009] Important features of the invention in the method for operating a vehicle, in particular a rail vehicle, with a first drive, with a second drive and with a load, in particular with a load to be transported by the vehicle, are that the first drive drives a first wheel, in particular a drive wheel, of the vehicle and wherein the second drive drives a second wheel, in particular a drive wheel, of the vehicle, wherein a target speed value is determined from a target speed of the vehicle, in particular wherein a time-dependent course of the target speed value is specified, wherein the sum of the target speed value and a deviation value is used as the target speed value of the first drive and the difference between the target speed value and the deviation value is used as the target speed value of the second drive, wherein the deviation value is set such that an actual bending value,in particular, an actual bending value assigned to a mast connecting the two drives is adjusted to a bending target value.
[0010] The advantage here is that the deflection can be limited and thus remains below a critical value. This increases reliability and safety, as overloading of the vehicle is prevented.
[0011] In an advantageous embodiment, the first drive is operated in field-oriented control and the second drive is also operated in field-oriented control. It is advantageous here that a motor model is calculated within the control system, with which a value for the torque generated by the electric motor is determined. This makes it possible for the method according to the invention to use the torque values determined in this way to determine a bending target value. If a sensor for determining the angular position of the rotor of the electric motor is arranged on the electric motor, the position of the carriage driven by the respective electric motor is also known and can be used to determine the actual bending value. In particular, slip-free movement of the wheels relative to the rails is assumed here.
[0012] In an advantageous embodiment, each of the two drives has a speed controller with a subordinate torque control. This is advantageous in that a setpoint for the torque can be specified and an actual torque value is determined. These values can thus be used according to the invention.
[0013] In an advantageous embodiment, the first drive comprises a first electric motor, which drives the first wheel directly or via a first transmission and is powered by a first converter. Advantageously, the vehicle comprises two carriages that are spaced apart from one another and mechanically coupled, in particular via a mast. Thus, bending can be utilized for wheels of different speeds, as long as the bending remains below a maximum bending value.
[0014] In an advantageous embodiment, the second drive comprises a second electric motor, which drives the second wheel directly or via a second transmission and is powered by a second converter, in particular wherein each of the electric motors is designed as a three-phase motor. Advantageously, the vehicle comprises two carriages that are spaced apart from one another and mechanically coupled to one another, in particular via a mast. Thus, bending can be utilized for wheels with different speeds, as long as the bending remains below a maximum bending value.
[0015] In an advantageous embodiment, a first model value M1 of the torque output by the first electric motor or drive is determined, in particular in a motor model of the field-oriented control of the first converter, while a second model value M2 of the torque output by the second electric motor or drive is determined, in particular in a motor model of the field-oriented control of the second converter. The advantage here is that the torque values are available without additional effort and can be used according to the invention.
[0016] In an advantageous embodiment, the bending setpoint is set and / or provided by a controller, in particular a PI controller, such that the difference, in particular the control deviation, between the first model value M1 and the second model value M2, which is multiplied in particular by a coupling factor, is determined and controlled to zero. It is advantageous that the controller's control objective is to achieve equality of the torques, taking the coupling factor into account. The coupling factor depends on the load case and / or the curvature of the rails. Therefore, a different coupling factor can be used when cornering than when traveling straight ahead.
[0017] In an advantageous embodiment, the bending setpoint determined by the controller, in particular a PI controller, is limited and / or restricted to a maximum bending value. This is advantageous because the bending is kept below a critical value, thus avoiding mechanical risks.
[0018] In an advantageous embodiment, the maximum bending value is set to zero when the target speed value disappears. The advantage here is that bending can be prevented depending on the load case and / or the target speed profile.
[0019] In an advantageous embodiment, the load is supported centrally or off-center relative to the two drives of the vehicle, and / or the center of mass of the load is spaced apart from both drives, in particular evenly or unevenly. This is advantageous because different positions of the load relative to the drives result in a different load case and are taken into account accordingly according to the invention.
[0020] In an advantageous embodiment, the actual bending value is provided by a sensor and / or is determined from position values, in particular angular positions, of the two drives or of the two carriages driven by the drives, which are recorded in particular with angle sensors of the drives.
[0021] The advantage here is that the actual bending value is provided by a sensor, such as a strain gauge or similar, and thus the actual mechanical bending is directly recorded, or a bending value is determined from the position values of the drives. The position values are either recorded directly or calculated from a model. Using the directly recorded positions of the carriages, a high level of reliability can be achieved.
[0022] In an advantageous embodiment, the first drive is operated with a lower power than the second drive and / or the product of the speed setpoint (nSolH) of the first drive and the first model value M1 of the torque output by the first electric motor or drive is smaller than the product of the speed setpoint (nSoll2) of the second drive and the second model value M2 of the torque output by the second electric motor or drive. The advantage here is that the bend can be used to support the weaker drive with feed force from the stronger drive. A non-zero bend is therefore permitted and used to transfer a feed force component from the stronger to the weaker drive. The first drive is preferably weaker than the second drive.
[0023] Alternatively, the conditions can also be reversed, in particular the first drive is stronger than the second drive.
[0024] Important features of the vehicle are that the vehicle has the first and the second drive, wherein the first drive is connected to the second drive by means of a mast, wherein the first wheel driven by the first drive rolls on a first rail and the second wheel driven by the second drive rolls on a second rail, wherein the first rail is aligned parallel to the second rail, in particular wherein the first rail is arranged below the second rail in the direction of gravity. It is advantageous that a means for limiting the bending is provided in that the controller is designed to keep a bending target value below a maximum bending value and thus regulates the actual bending value towards this limited bending target value. The vehicle is thus protected from mechanical overload and achieves a long service life.It is particularly important that the load is picked up by the vehicle between the two drives and is arranged so that it can be moved along the vehicle's mast. This enables the load to be moved, in particular lifting and lowering and / or moving the load transversely along the mast. The mast connects the two drives and, depending on the different target positions or target speeds of the drives, undergoes bending, which is kept below the maximum bending value. In particular, when the vehicle is stationary, the bending is brought to zero. The vehicle is preferably designed as a storage and retrieval machine that is guided on two rails, in particular with a first of the rails on the floor and a second of the rails on the ceiling or at least above the first rail. The wheels of the vehicle driven by the drives preferably roll along the rails without slippage.Alternatively, the first rail is aligned parallel to the second rail but positioned differently relative to the second rail. For example, both rails are arranged together in a horizontal plane.
[0025] Further advantages emerge from the dependent claims. The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the problem and / or the problem posed by comparison with the prior art.
[0026] The invention will now be explained in more detail using schematic illustrations:
[0027] Figure 1 shows a schematic representation of a method according to the invention for operating a system.
[0028] Figure 2 shows a schematic representation of the system for three different load cases L1, L2, L3.
[0029] As shown in the figures, the system comprises a first drive 1, which drives a first carriage 21, whose wheels, in particular rail wheels, driven by the first drive 1 roll along the first rail 24. The first drive 1 generates a first torque M1 such that the first carriage 21 experiences a first driving force F1, in particular a first traction force.
[0030] Accordingly, the system has a second drive 2 that drives a second carriage 22, whose wheels, in particular rail wheels, driven by the second drive 2 roll along the second rail 25. The second drive 2 generates a second torque M2 such that the second carriage 22 experiences a second driving force F2, in particular a second traction force.
[0031] The first rail 24 is preferably arranged above the second rail 25.
[0032] The first carriage 21 is arranged on a mast on which the second carriage 22 is also arranged.
[0033] The vehicle formed by the mast and the two carriages (21, 22) is intended for transporting a load 23. For example, the vehicle is a storage and retrieval machine, and the system is a warehouse having shelves for storing and retrieving the load 23, which has a significant mass, particularly compared to the mass of the mast and / or the carriages 21 and 22.
[0034] The load 23 is attached to the mast. Depending on the height of the load 23 and the
[0035] Forces F1 and F2 create bending forces in the mast. To prevent damage, the bending is limited by the control system by specifying the deviation between the target speeds of the two drives (1, 2) in such a way that the bending is limited.
[0036] Each of the drives (1, 2) is operated in field-oriented control, i.e. with a speed controller to which a torque controller is subordinate.
[0037] In load case L1, the load 23 is closer to the second carriage 22 than to the first carriage 21. Thus, the second drive 2 must apply a correspondingly large traction force F2. If this traction force F2 is small, the first carriage 21 will move ahead, resulting in a non-zero deflection, which is limited according to the invention to prevent a critically large deflection value from occurring.
[0038] In load case L2, the mass 23 is arranged centrally between the two carriages 21 and 22.
[0039] Therefore, no bending is allowed for forces F1 and F2 that are essentially equal.
[0040] In load case L3, the load 23 is closer to the first carriage 21 than to the second carriage 22. Thus, the first drive 1 must apply a correspondingly large traction force F1. If this traction force F1 is small, the second carriage 22 will move ahead, resulting in a non-zero deflection, which is limited according to the invention to prevent a critically large deflection value from occurring.
[0041] To execute a travel task, the vehicle is given a time-dependent speed curve nSoll_ProfGen, which is determined from a time-dependent target position curve. From this speed curve, a target speed is determined for both drives 1 and 2, taking into account the diameters of the wheels driven by drives 1 and 2.
[0042] According to the invention, however, the target speed nSolH for the first drive 1 is increased by a speed deviation value 11 and the target speed nSoll2 for the second drive 2 is reduced by this deviation value 11.
[0043] A means 3 for determining the actual bending value 4 determines the actual bending value 4 from the actual positions of the two drives (1, 2). Alternatively, the actual bending value can be determined by an inclination sensor mounted on the mast. Alternatively, the actual bending value 4 can also be determined by temporally integrating the difference between the actual values of the rotational speeds of the two drives 1 and 2, in particular, whereby a divergence of the integral can be avoided by recurring calibration or zeroing in load case L2.
[0044] The difference between a bending setpoint 8 and the bending actual value 4 is fed to a controller 9, in particular a PI controller, whose output signal is fed to a proportional element 10, which provides the speed deviation value 11 at its output.
[0045] In order to determine the bending setpoint, the respective torque model value (M1, M2) formed within the field-oriented control of each of the two drives (1, 2) is used.
[0046] The field-oriented control of the first drive 1 forms a model value M1 for the torque output by the electric motor of the first drive 1 and the field-oriented control of the second drive 2 forms a model value M2 for the torque output by the electric motor of the second drive 2.
[0047] In addition, the model value M2 of the torque of the second drive 2 is multiplied by a coupling factor 6, in particular by a further proportional element. In particular, the coupling factor is adapted to the curvature of the rails (24, 25) and thus has different values when cornering or traveling straight ahead.
[0048] The difference between the first model value M1 for torque and the second model value M2 for torque multiplied by the coupling factor 6 is fed to a controller, in particular a PI controller, whose output signal determined as a control value is fed to a limiting means 8, in particular for limiting to a maximum bending value 5.
[0049] The maximum bending value 5 depends on the load case (L1, L2, L3). Therefore, if the load 23 is positioned centrally between the two drives (1, 2), a very small limit value close to zero can be specified. Similarly, at standstill, especially when the speed is zero, the maximum bending value 5 can be specified as zero, regardless of the position of the load 23. The output signal of the limiter 8 is used as the bending setpoint.
[0050] In further embodiments according to the invention, instead of the torques of the electric motors of the drives (1, 2), the torques delivered by the drives (1, 2) to the wheels of the carriages (21, 22) can also be used.
[0051] In further embodiments according to the invention, the first drive is operated with a lower or higher power than the second drive. Thus, the two drives do not have to be the same size, but can also have different power outputs. Thus, if the nominal power, in particular the maximum power, of the two drives is different, the method according to the invention enables a consistently high utilization of the installed power. Thus, by specifically utilizing the permissible bending of the mast, part of the thrust force can be transferred from the less loaded drive, for example the first drive, to the other, for example the second drive. The installed drive power can thus be planned and / or used efficiently and effectively.
[0052] List of reference symbols
[0053] 1 first drive
[0054] 2 second drive
[0055] 3 Means for determining the actual bending value 4
[0056] 4 Actual bending value
[0057] 5 Maximum bending value
[0058] 6 Proportional element for multiplication with coupling factor
[0059] 7 controllers, especially PI controllers
[0060] 8 Limiting means, in particular for limiting to a maximum bending value
[0061] 9 Controllers, especially PI controllers
[0062] 10 Proportional element
[0063] 11 Speed deviation value
[0064] 21 first car
[0065] 22 second car
[0066] 23 Load, especially mass
[0067] 24 first rail
[0068] 25 second rail nSolH Speed setpoint for the first drive 1 nSoll2 Speed setpoint for the first drive 2 nSoll_ProfGen Time-dependent speed curve as target specification for the vehicle
[0069] L1 first load case
[0070] L2 second load case
[0071] L3 third load case
[0072] F1 first driving force, especially traction force
[0073] F2 second driving force, especially traction force
Claims
Patent claims:
1. A method for operating a vehicle, in particular a rail vehicle, with a first drive, with a second drive and with a load, in particular with a load to be transported by the vehicle, wherein the first drive drives a first wheel, in particular a drive wheel, of the vehicle and wherein the second drive drives a second wheel, in particular a drive wheel, of the vehicle, wherein a target speed value (nSoll_ProfGen) is determined from a target speed of the vehicle, in particular wherein a time-dependent profile of the target speed value is specified, characterized in that the sum of the target speed value (nSoll_ProfGen) and a deviation value (11) is used as the target speed value (nSolH) of the first drive and the difference between the target speed value (nSoll_ProfGen) and the deviation value (11) is used as the target speed value (nSoll2) of the second drive, wherein the deviation value is set such that an actual bending value,in particular, an actual bending value assigned to a mast connecting the two drives is adjusted to a bending target value.
2. Method according to claim 1, characterized in that the first drive is operated in field-oriented control and the second drive is also operated in field-oriented control.
3. Method according to one of the preceding claims, characterized in that each of the two drives has a speed controller with subordinate torque control.
4. Method according to one of the preceding claims, characterized in that the first drive has a first electric motor which drives the first wheel directly or via a first transmission and which is fed by a first converter, and / or that the second drive has a second electric motor which drives the second wheel directly or via a second transmission and which is fed by a second converter, in particular wherein each of the electric motors is designed as a three-phase motor.
5. Method according to one of the preceding claims, characterized in that a first model value M1 of the torque output by the first electric motor or drive is determined, in particular in a motor model of the field-oriented control of the first converter, wherein a second model value M2 of the torque output by the second electric motor or drive is determined, in particular in a motor model of the field-oriented control of the second converter.
6. Method according to one of the preceding claims, characterized in that the bending setpoint is set and / or provided by a controller, in particular a PI controller, in such a way that the difference, in particular control deviation, between the first model value M1 and the second model value M2, in particular multiplied by a coupling factor, is determined and regulated to zero.
7. Method according to one of the preceding claims, characterized in that the bending setpoint determined by the controller, in particular PI controller, as a control value is limited and / or restricted in amount to a maximum bending value.
8. Method according to one of the preceding claims, characterized in that when the target speed value disappears, the maximum bending value is set to zero.
9. Method according to one of the preceding claims, characterized in that the load is taken up by the vehicle centrally or off-center to the two drives and / or wherein the center of mass of the load is spaced from both drives, in particular evenly or unevenly.
10. Method according to one of the preceding claims, characterized in that the actual bending value is provided by a sensor and / or from values recorded, in particular with angle sensors of the drives. Position values, especially angular positions, of the two drives are determined.
11. Method according to one of the preceding claims, characterized in that the first drive is operated with a lower power than the second drive and / or that the product of the speed setpoint (nSolH) of the first drive and the first model value M1 of the torque output by the first electric motor or drive is smaller than the product of the speed setpoint (nSoll2) of the second drive and the second model value M2 of the torque output by the second electric motor or drive.
12. Method according to one of claims 1 to 10, characterized in that the first drive is operated with a greater power than the second drive and / or that the product of the speed setpoint (nSolH) of the first drive and the first model value M1 of the torque output by the first electric motor or drive is greater than the product of the speed setpoint (nSoll2) of the second drive and the second model value M2 of the torque output by the second electric motor or drive.
13. Vehicle suitable for carrying out a method according to one of the preceding claims, wherein the vehicle has the first and the second drive, wherein the first drive is connected to the second drive by means of a mast, wherein the first wheel driven by the first drive rolls on a first rail and the second wheel driven by the second drive rolls on a second rail, wherein the first rail is aligned parallel to the second rail, in particular wherein the first rail is arranged below the second rail in the direction of gravity.
14. Vehicle according to one of the preceding claims, characterized in that the first drive has a lower rated power than the second drive and / or a lower maximum power than the second drive or that the first drive has a higher rated power than the second drive and / or a higher maximum power than the second drive.