Driving control method and driving control system for double-rotor trolley

Abstract

The invention discloses a driving control method and a driving control system for a double-mover trolley, the double-mover trolley moves on a power rail, double movers are connected in the extending direction of the power rail in a front-back mode, and any mover has a zero-torque mode without force output and a position mode with force output. The double-mover trolley driving control method comprises the steps that the double-mover trolley has a preset target track and an actual motion track moving along the target track, and when one mover is switched from a zero torque mode to a position mode, the current position and the current speed of the corresponding mover are calculated based on the current position and the current speed of the corresponding mover when a switching instruction is received; and obtaining a prediction position after the switching period, and adjusting the target track according to the prediction position. Compared with the prior art, the double-rotor driving trolley has the advantages that the driving capacity of the trolley can be improved by adopting double-rotor driving, and meanwhile, the shaking condition of the rotors in the dynamic switching process is avoided.

Description

Technical Field

[0001] This invention relates to a drive control method and drive control system for a dual-motor trolley, belonging to the field of motor controller technology. Background Technology

[0002] In material handling or processing systems based on magnetic levitation lines, the moving trolley (or carrier) is the key actuator for achieving precise movement of items. Currently, common solutions mainly employ single-moving trolleys and dual-moving trolleys, but both solutions have significant limitations when addressing specific application requirements.

[0003] Single-actuated trolleys are typically powered by a single electromagnetic drive unit. Their inherently low driving force limit makes them unsuitable for continuous and stable propulsion over long distances or under conditions requiring high acceleration / load. In long-distance or high-load scenarios, single-actuated trolleys may experience insufficient thrust, speed fluctuations, or even failure to complete the predetermined stroke. Furthermore, due to the physical structure of the single-actuated trolley, its carrying platform (carrier) is usually short. When used to process or transport products or workpieces whose length is significantly greater than the carrier itself, single-actuated trolley solutions exhibit serious inadequacies. Transporting long items on short carriers easily leads to overall instability, inducing significant back-and-forth swaying (pitch vibration) during startup, braking, or operation. This instability not only affects transmission accuracy and processing quality but may also pose safety hazards and even damage products or equipment.

[0004] To overcome the limitations of single-motor trolleys in terms of vehicle length and load capacity, dual-motor trolley solutions have emerged. This solution uses two motor units to collaboratively drive an extended vehicle platform. Its core advantages lie in effectively extending vehicle length and improving operational stability. However, dual-motor trolleys face a critical technical challenge in practical operation: coordinating and dynamically switching the output between the motors. During operation, based on path planning, load distribution, or energy-saving requirements, the system needs to dynamically adjust the working states of the two motors (for example, one motor may be propelling while the other merely levitates or exerts very little force; or the primary propulsion motor may switch in specific sections). Existing technologies often struggle to guarantee strict, real-time coordination between the two motors when implementing this dynamic output allocation and role switching. Failure of this coordination control leads to unbalanced output, meaning the thrust exerted by the two motors on the vehicle cannot be precisely matched, resulting in unexpected internal forces. Switching-through jitter: At the instant of switching between the driving roles (such as "propeller" and "slave"), due to control delays, parameter mismatches, or force coupling, severe jitter (abnormal vibration) of the vehicle platform can easily occur. This jitter not only disrupts the stability of system operation, affecting positioning accuracy and processing results, but also increases mechanical stress, generates noise, and may shorten the service life of the equipment. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a dual-motor trolley drive control method, which can expand the trolley's driving capability and simultaneously solve the problem of trolley vibration caused during dynamic switching of the motors.

[0006] The technical solution of this invention is:

[0007] A dual-motor trolley drive control method is provided for the dual-motor trolley to move on a power track. The dual motors are connected front and rear to each other in the extension direction of the power track, and each motor has a zero-torque mode (no power output) and a position mode (power output). The dual-motor trolley drive control method includes: the dual-motor trolley has a preset target trajectory and an actual motion trajectory along the target trajectory; when one of the motors switches from the zero-torque mode to the position mode, based on the current position and current speed of the corresponding motor when the switching command is received, a predicted position after the switching cycle is obtained, and the target trajectory is adjusted according to the predicted position.

[0008] As a further improvement of the present invention, the power track includes at least two power sections and a non-powered section connecting the two power sections, and during the movement of the dual-motor trolley, at least one mover is located on the power section.

[0009] As a further improvement of the present invention, the dual movers include a first mover and a second mover connected synchronously front and rear. The first mover is disposed close to the unpowered section, and during the movement of the first mover from the first powered section through the unpowered section to the second powered section, the first mover switches from the torque module to the position mode; during the movement of the second mover from the first powered section through the unpowered section to the second powered section, the first mover switches from the position module to the zero torque mode and then is switched back to the position mode by the torque module.

[0010] As a further improvement of the present invention, when the second mover is located in the first powered segment or the unpowered segment, the first mover and the second mover are controlled to be in different motion modes; when the second mover is located in the second powered segment, both the first mover and the second mover are controlled to be in position mode.

[0011] As a further improvement of the present invention, a prediction model is established based on the current position and current velocity of the corresponding mover when the switching command is received, and the predicted position after the switching cycle is obtained through the prediction model. The prediction model includes calculating the sum of the current position of the corresponding mover and the distance traveled after the switching cycle at a constant current velocity, so as to calculate and predict the predicted position after the switching cycle.

[0012] As a further improvement of the present invention, the power segment has at least one of an acceleration segment, a deceleration segment, and a constant speed segment. When one of the movers switches from zero torque mode to position mode, the prediction model further includes predicting the predicted position after the switching cycle based on the acceleration of the corresponding mover when the switching command is received.

[0013] As a further improvement of the present invention, the prediction model also includes compensation parameters. The predicted position is the sum of the current position of the corresponding mover, the distance traveled after passing through the switching cycle at the current speed, and the compensation parameters. The compensation parameters are the product of the current speed and a fixed compensation coefficient.

[0014] As a further improvement of the present invention, the dual-motor sub-car includes a controller and a motor module communicatively connected to the controller. The controller is configured to transmit the predicted position to the motor module and output a corresponding speed control command through the motor module.

[0015] As a further improvement of the present invention, the motor module is provided with a three-loop control model, which includes a position control module, a speed control module and a current control module that are interconnected. The position control module is used to receive the predicted position and output the corresponding speed control command. The speed control module receives the speed control command and outputs the corresponding current control command. The current control module receives the current control command and outputs the corresponding current.

[0016] To address the aforementioned technical problems, this invention provides a dual-motor trolley drive control system. This drive control system can expand the trolley's driving capability and simultaneously solve the problem of trolley vibration caused during dynamic motor switching.

[0017] The technical solution of this invention is:

[0018] A dual-motor trolley drive control system, applying the aforementioned dual-motor trolley drive control method, the dual-motor trolley drive control system includes a dual-motor trolley and a power track for the dual-motor trolley to slide on, the power track includes at least two power sections and a non-powered section connecting the two power sections, during the movement of the dual-motor trolley from the first power section through the non-powered section to the second power section, the two motors respectively exert force and drive the dual-motor trolley to move along the power track.

[0019] The beneficial technical effects of this invention are as follows: The dual-motor trolley drive control method of this invention uses a dual-motor drive mode to transport an extended vehicle platform to accommodate longer processing products, thus expanding its application scope. Furthermore, compared to the original single-motor drive mode, the dual-motor drive force is also more powerful, capable of adapting to the needs of longer tracks. In addition, the dual-motor trolley drive control method of this invention, based on a preset target trajectory and the actual motion trajectory along the target trajectory, obtains a predicted position after a switching cycle based on the current position and current speed of the corresponding motor when one motor switches from zero torque mode to position mode (i.e., from no-power mode to power-power mode) upon receiving the switching command. The target trajectory is then adjusted according to the predicted position, thereby solving the power-power switching problem during motor movement and avoiding trolley vibration caused by the motor switching process. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the dual-motor trolley drive control system conforming to the present invention.

[0021] Figure 2 yes Figure 1 A structural block diagram of the controller and motor module of the dual-action trolley.

[0022] Figure 3 yes Figure 1 The trajectory diagram of the target trajectory, actual motion trajectory, and adjusted target trajectory of the dual-motor trolley. Detailed Implementation

[0023] In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0024] Please see Figure 1 As shown, the present invention discloses a dual-motor trolley drive control system 100, including a dual-motor trolley 1 and a power track 2 for sliding the dual-motor trolley 1. The power track 2 includes at least two power sections 21 and a non-powered section 23 connecting the two power sections 22. During the movement of the dual-motor trolley 1 from the first power section 21 through the non-powered section 23 to the second power section 22, the two motors respectively exert force and drive the dual-motor trolley 1 to move along the power track 2.

[0025] In the use of existing magnetic levitation lines, the limitations of actual physical space lead to a disproportionate relationship between the track length and the standard magnetic levitation line. For example, the standard magnetic levitation straight line is 480mm long, but in actual use, customers require a 2000mm straight section, which, combined with four standard modules, results in a length of 1960mm, creating a 40mm length deviation. Customization would lead to a wide variety of products, hindering standardized production. Therefore, in this invention, by using the unpowered section 23 to connect two powered sections, the length of this section can be effectively supplemented, and the dual-motor trolley 1 can traverse this unpowered section 23. Thus, the design of the unpowered section 23 in this invention can adapt to various track schemes when the line length is not standard, or to some track sections that the standard modules cannot pass through. Furthermore, compared to a single-motor trolley, the dual-motor trolley 1 can carry a larger platform to transport larger-scale processed products, thus broadening its application range. The driving force of the double-moving trolley 1 is stronger than that of the single-moving trolley, and it can pass through the unpowered section 23 more smoothly by pushing the two moving parts back and forth.

[0026] Specifically, the two movers are mechanically connected to ensure synchronous drive. In this embodiment, the two movers switch between master and slave modes as they pass through the unpowered section 23. Therefore, the distance of the unpowered section 23 is less than the interval between the two movers. As a result, only one mover moves on the unpowered section 23 at a time, and the mover on the unpowered section 23 is not exerting force. In this way, it can be ensured that when the two-motor trolley 1 passes through the unpowered section 23, one mover is also powered, allowing it to pass through the unpowered section 23 at a relatively stable speed, rather than through inertial deceleration.

[0027] In this embodiment, the dual movers include a first mover 31 and a second mover 32 connected synchronously. The first mover 31 is located close to the unpowered section 23. During the movement of the first mover 31 from the first powered section 21 through the unpowered section 23 to the second powered section 22, the first mover 31 switches from the torque module to the position mode. During the movement of the second mover 32 from the first powered section 21 through the unpowered section 23 to the second powered section 22, the first mover 31 switches from the position module to the zero torque mode and then is switched back to the position mode by the torque module.

[0028] That is, when in the first power section 21, the first mover 31 at the front does not exert force, and the movement of the double-moving-cart 1 is entirely provided by the second mover 32, and this state is maintained as it enters the unpowered section 23. At this time, the double-moving-cart 1 is in a state of being pushed by the second mover 32 at the rear. When the first mover 31 enters the second power section 22, the first mover 31 switches from a zero-torque mode without exerting force to a position mode with exerting force, while the second mover 32 switches from a position mode with exerting force to a zero-torque mode without exerting force. At this time, the double-moving-cart 1 is in a state of being pulled by the first mover 31 at the front. Therefore, the operating logic of the double-moving-cart 1 can be summarized as a push-and-pull operation mode.

[0029] Preferably, each of the two movers has a zero-torque mode (no power output) and a power output mode. When a mover is in zero-torque mode, it is equivalent to the torque command for that mover being 0. When a mover switches modes, it is either about to enter the unpowered segment 23 or exiting the unpowered segment 23 to enter the powered segment.

[0030] Please see Figure 2 As shown, the dual-action sub-car 1 includes a controller 4 and a motor module 5 that is communicatively connected to the controller 4. The controller 4 is configured to transmit the predicted position to the motor module 5 and output the corresponding speed control command through the motor module 5.

[0031] The motor module 5 is provided with a three-loop control model 51. The three-loop control model 51 includes a position control module 511, a speed control module 512, and a current control module 513 that are interconnected. The position control module 513 is used to receive the predicted position and output the corresponding speed control command. The speed control module receives the speed control command and outputs the corresponding current control command. The current control module receives the current control command and outputs the corresponding current.

[0032] When the mover switches from a zero-torque mode (no power output) to a position mode (power output), there is often a delay in commands and feedback due to the need for dynamic switching in motion engineering. This is because commands are usually issued through communication between the controller and the motor module. However, the communication between controller 4 and motor module 5 relies on bus communication and the program has a scan cycle, which causes a delay in commands and feedback. Therefore, position command prediction and synchronization are required.

[0033] Specifically, controller 4 and motor module 5 communicate via a bus (such as EtherCAT or PROFINET), and the program execution of controller 4 has a scan cycle. From the time controller 4 issues the "switching command + new target command" to the driver receiving and executing it, and then to the actual thrust generation, there is a non-negligible communication delay, calculation delay, and execution delay. During the delay time, the mover is still gliding at its current speed. Its actual position and actual speed have changed. Controller 4 calculates the new target position command based on the state at the first moment (motor position and speed at the first moment). However, this command only takes effect after the delay time. At this time, the actual position of the mover is the sum of the mover position at the first moment and the distance traveled at the mover speed at the first moment after the delay time, while the target command is still calculated based on the state at the first moment. This obviously has a large delay, thus causing the dual-motor trolley to suddenly accelerate or decelerate before moving smoothly again, i.e., causing the trolley to shake.

[0034] Therefore, please refer to Figure 3 As shown, this invention provides a dual-motor vehicle drive control method to solve the problem of dual-motor vehicle jitter. The dual-motor vehicle drive control method includes: the dual-motor vehicle 1 has a preset target trajectory L1 and an actual motion trajectory L2 along the target trajectory L1; when one of the movers switches from a zero-torque mode to a position mode, based on the current position and current speed of the mover at the time of receiving the switching command, a predicted position after a switching cycle is obtained, and the target trajectory L1 is adjusted according to the predicted position to form a new target predicted trajectory L3. Wherein, R1 and R2 correspond to the motion trajectories of the two movers, respectively, and these motion trajectories correspond to the target trajectory L1, the actual motion trajectory L2, and the new target predicted trajectory L3. Figure 3 In the process, the new target prediction trajectory L3 of R2 is not identified, but it will still appear during the switching process.

[0035] Specifically, errors are inevitable in the commands given to the dual-action sub-car. Therefore, on the pre-planned target trajectory L1, there exists a target switching position for changing modes. However, the switching action will inevitably be delayed between the issuance and receipt of the command, resulting in an error between the target switching position and the actual switching position. Therefore, in this invention, at time t1 when the switching command is received, the current actual position R0 is recorded, and the position increment for a future period is calculated based on the current speed V0. After compensation is completed and at time t2, the trajectory is replanned based on the last predicted position to achieve a dynamic switching process from no power to power output.

[0036] The dual-motor trolley drive control method further includes: establishing a prediction model based on the current position and current speed of the corresponding motor when the switching command is received, and obtaining the predicted position after the switching cycle through the prediction model. The prediction model includes calculating the sum of the current position of the corresponding motor and the travel distance after the switching cycle at the current speed, so as to calculate and predict the predicted position after the switching cycle.

[0037] In this embodiment, to ensure accuracy, the prediction model further includes compensation parameters. The predicted position is the sum of the current position of the corresponding mover, the distance traveled after passing through the switching cycle at the current speed, and the compensation parameters. The compensation parameters are the product of the current speed and a fixed compensation coefficient.

[0038] The prediction model uses the following formula for prediction:

[0039] R (t) =R0 + V0 × t + V0 × K + 1 / 2 × at 2 Where t represents the prediction time (t2-t1), a represents the acceleration (which is 0 if the velocity is constant), and K represents the reciprocal of the gain parameter in position control. The required position deviation at the current velocity can be calculated using the current velocity and the gain coefficient, and then superimposed on the initial position to obtain the predicted target position. This formula uses a second-order calculation; however, in other embodiments, higher-order calculation methods can be used depending on the actual situation, and there is no limitation on this.

[0040] like Figure 3 As shown, t1 to t2 is the time interval for switching modes, which is also the prediction time interval for predicting the new target trajectory L3 based on the current position and velocity. Therefore, the new target trajectory L3 should be adjusted and switched complete at t2.

[0041] The power segment has at least one of an acceleration segment, a deceleration segment, and a constant speed segment. When one of the movers switches from zero torque mode to position mode, the prediction model also includes predicting the predicted position after the switching cycle based on the acceleration of the corresponding mover when the switching command is received. Therefore, the power segment is not limited to constant speed travel, but can be adjusted according to actual needs; it can be an acceleration segment, a deceleration segment, or a combination of all three. What we need to capture is the acceleration when the switching command is received.

[0042] In summary, the dual-motor trolley drive control method and drive control system of the present invention, by employing a dual-motor drive mode to transport an extended vehicle platform, can accommodate longer processing products, thus expanding its application scope. Furthermore, compared to the original single-motor drive mode, the dual-motor drive force is also more powerful, capable of adapting to the needs of longer tracks. In addition, the dual-motor trolley drive control method of the present invention, based on a preset target trajectory L1 and the actual motion trajectory L2 along the target trajectory L1, obtains a predicted position after a switching cycle based on the current position and current speed of the corresponding motor when one motor switches from zero torque mode to position mode (i.e., from no-power mode to power-power mode) upon receiving the switching command, and adjusts the target trajectory L1 according to the predicted position. This solves the power-power switching problem during motor movement and avoids trolley vibration caused by the motor switching process.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for driving and controlling a dual-motor trolley, wherein the dual-motor trolley moves on a power track, the dual motors are connected front and rear to each other along the extension direction of the power track, and each motor has a zero-torque mode (no power output) and a position mode (power output), characterized in that, The dual-motor trolley drive control method includes: the dual-motor trolley has a preset target trajectory and an actual motion trajectory along the target trajectory; when one of the movers switches from zero torque mode to position mode, based on the current position and current speed of the corresponding mover when the switching command is received, the predicted position after the switching cycle is obtained, and the target trajectory is adjusted according to the predicted position.

2. The dual-motor trolley drive control method according to claim 1, characterized in that, The power track includes at least two power sections and a non-powered section connecting the two power sections. During the movement of the dual-motor trolley, at least one mover is located on the power section.

3. The dual-motor trolley drive control method according to claim 2, characterized in that, The dual-movement mechanism includes a first mover and a second mover connected synchronously. The first mover is positioned close to the unpowered section. During the movement of the first mover from the first powered section through the unpowered section to the second powered section, the first mover switches from the torque module to the position mode. During the movement of the second mover from the first powered section through the unpowered section to the second powered section, the first mover switches from the position module to the zero-torque mode and then back to the position mode by the torque module.

4. The dual-motor trolley drive control method according to claim 3, characterized in that, When the second mover is in the first powered segment or the unpowered segment, the first mover and the second mover are controlled to be in different motion modes. When the second mover is in the second powered segment, the first mover and the second mover are controlled to be in position mode.

5. The dual-motor trolley drive control method according to claim 2, characterized in that, Based on the current position and current velocity of the corresponding mover when the switching command is received, a prediction model is established and the predicted position after the switching cycle is obtained through the prediction model. The prediction model includes calculating the sum of the current position of the corresponding mover and the distance traveled after the switching cycle at a constant current velocity, so as to calculate and predict the predicted position after the switching cycle.

6. The dual-motor trolley drive control method according to claim 5, characterized in that, The power segment has at least one of an acceleration segment, a deceleration segment, and a constant speed segment. When one of the movers switches from zero torque mode to position mode, the prediction model also includes predicting the predicted position after the switching cycle based on the acceleration of the corresponding mover when the switching command is received.

7. The dual-motor trolley drive control method according to claim 5, characterized in that, The prediction model also includes compensation parameters. The predicted position is the sum of the current position of the corresponding mover, the distance traveled after passing through the switching cycle at the current speed, and the compensation parameters. The compensation parameters are the product of the current speed and a fixed compensation coefficient.

8. The dual-motor trolley drive control method according to claim 1, characterized in that, The dual-action sub-car includes a controller and a motor module that is communicatively connected to the controller. The controller is configured to transmit the predicted position to the motor module and output the corresponding speed control command through the motor module.

9. The dual-motor trolley drive control method according to claim 8, characterized in that, The motor module is equipped with a three-loop control model, which includes a position control module, a speed control module, and a current control module that are interconnected. The position control module receives the predicted position and outputs a corresponding speed control command. The speed control module receives the speed control command and outputs a corresponding current control command. The current control module receives the current control command and outputs a corresponding current.

10. A drive control system for a dual-motor trolley, characterized in that, The dual-motor trolley drive control method according to any one of claims 1-9 includes a dual-motor trolley and a power track for sliding the dual-motor trolley. The power track includes at least two power sections and a non-power section connecting the two power sections. During the movement of the dual-motor trolley from the first power section through the non-power section to the second power section, the two motors respectively exert force and drive the dual-motor trolley to move along the power track.

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