Dynamic control of artificially tethered electrically powered towed vehicles

Abstract

An electric pallet (e-pallet) includes an upper structure mounted to a wheeled base platform. A tethering device defines a hinge angle relative to a front edge of the upper structure and is grasped by an operator towing the electric pallet. A motor connected to driven wheels transmits drive torque to the wheels in response to a motor control signal that includes a desired yaw rate and a ground speed. A speed sensor, an angle sensor, and a length sensor are respectively configured to determine an actual ground speed of the electric pallet, the hinge angle, and a length of the tethering device. In response to input signals, an electronic controller generates the motor control signal using proportional-integral-derivative (PID) control logic. Coupled lateral and longitudinal dynamic control loops respectively determine the desired yaw rate and the ground speed to accommodate motion of the operator.

Description

Background Technology

[0001] Manufacturing plants and warehouse facilities require the coordinated movement of raw materials, sub-components, and finished parts, often over considerable distances. Larger or relatively heavy loads are typically transported using forklifts, tractors, conveyors, and other powered equipment. In contrast, smaller loads can be moved using manually operated pallet trucks, wheeled trolleys, and handcarts. Overall, machine-driven and manually operated lifting aids improve overall productivity while significantly reducing load-related stress and strain on operators in the workplace. Summary of the Invention

[0002] This disclosure relates to methods and systems for controlling motor-driven electric pallets. Certain operations that do not require the assistance of generally heavy-duty power equipment of the types described above may still be unsuitable for relatively small, manually operated devices, such as handcarts and trolleys. In such cases, an operator can use an electric pallet having a container mounted on a wheeled platform, wherein the container and / or platform is connected to a flexible tethering device. As the operator grips the end of the tethering device and walks across the facility, the traction force applied by the operator propels the electric pallet in the direction of the operator's travel. When this occurs, an electric motor can provide motor drive torque to one or more wheels of the electric pallet to gently assist the traction force applied by the operator. Therefore, electric pallets facilitate the movement of goods and other loads in various facilities and industries.

[0003] Specifically, the disclosed control scheme aims to optimize the movement of an electric trailer configured in this manner. The tethering device envisioned herein is equipped with length and angle sensors, the corresponding outputs of which are transmitted as electronic control signals to an onboard electronic controller. The calculations and control actions performed by the electronic controller, which acts as a receiving node in this arrangement, enable the electric trailer to smoothly follow the desired trajectory initiated by the operator, while simultaneously allowing the movement of the electric trailer to remain robust against the operator's natural hand or arm swinging movements.

[0004] In some embodiments, the described electronic controller is configured to correct yaw commands based on a nonlinear function of the longitudinal speed of the electric trailer and the current length of the tethering device measured and reported by a length sensor contained in or connected to the electric trailer. Additionally, the electronic controller limits the longitudinal speed command of the electric trailer based on the speed or torque capability of the electric motor. As part of the envisioned control architecture, a lateral proportional-integral (PI) control loop is combined with a longitudinal PI control loop to create a dynamic response configured to closely match operator movement.

[0005] One aspect of this disclosure includes an electric trailer with a base platform, the superstructure being mounted on or integrally formed with the base platform. A tethering device connected to the superstructure defines a hinge angle (θ) relative to the leading edge of the superstructure and is configured to be gripped at one end by an operator when the electric trailer is towed. In this embodiment, two or more wheels are connected to the base platform. Additionally, at least one electric motor is operatively connected to the wheels and configured to transmit drive torque thereto. The drive torque transmission occurs in response to a motor control signal, wherein the motor control signal includes the desired yaw rate and desired ground speed of the electric trailer.

[0006] In this particular embodiment of the electric trailer, the sensor suite includes a speed sensor, an angle sensor, and a length sensor, configured to determine the actual ground speed of the electric trailer, the aforementioned articulation angle, and the length of the tethering device, respectively. An electronic controller communicating with the sensor suite is configured to generate motor control signals in response to input signals including the actual ground speed, articulation angle, and length. This occurs using resident proportional-integral-derivative (PID) control logic. The control logic envisioned herein includes a lateral dynamic control block / loop coupled to a longitudinal dynamic control block, wherein these blocks determine the desired yaw rate and ground speed of the electric trailer, respectively. In this way, the electronic controller is able to adapt to movements applied to the tethering device by the operator.

[0007] This document also discloses a method for controlling an electric trailer, the electric trailer having a superstructure mounted on or integrally formed with a base platform and a tethering device connected to the superstructure. The tethering device defines a hinge angle relative to the leading edge of the superstructure and is configured to be gripped at one end by an operator when the electric trailer is towed. In a possible implementation, the method includes determining a set of input signals, including measuring the actual ground speed of the electric trailer, the hinge angle between the tethering device and the leading edge of the superstructure, and the length of the electric trailer. In response to the input signals, the method includes generating a set of motor control signals using PID control logic of an electronic controller, the PID control logic having a lateral dynamic control loop coupled to a longitudinal dynamic control loop, the lateral dynamic control loop and the longitudinal dynamic control loop determining the desired yaw rate and the desired ground speed of the electric trailer, respectively.

[0008] In response to a desired yaw rate and ground speed, the method includes transmitting a set of motor control signals to electric motors connected to two or more driven wheels of an electric trailer, thereby providing drive torque to the electric motors to adapt to movement applied to the tethering device by an operator.

[0009] In another aspect of this disclosure, an electronic controller for an electric trailer includes a processor and a tangible non-transient memory, on which instructions are recorded for controlling the movement of the electric trailer when it is towed by an operator via a tethering device. Execution of the instructions by the processor causes the processor to receive input signals, including the actual ground speed of the electric trailer as measured by speed sensors, angle sensors, and length sensors, the hinge angle between the tethering device and the leading edge of the electric trailer, and the length of the tethering device, respectively. Instruction execution also causes the processor to generate a set of motor control signals in response to the input signals using the electronic controller's PID control logic. The PID control logic has a lateral dynamic control loop coupled to a longitudinal dynamic control loop, the lateral and longitudinal dynamic control loops determining the desired yaw rate and desired ground speed of the electric trailer, respectively. Furthermore, execution of the instructions causes the processor to transmit the set of motor control signals to at least one electric motor, so that one or more electric motors power one or more driven wheels of the electric trailer to adapt to the movement applied to the tethering device by the operator.

[0010] This application may also include the following schemes.

[0011] 1. An electric pallet, comprising:

[0012] A base platform having an upper structure mounted thereon or integrally formed therewith;

[0013] A tethering device is attached to the superstructure, wherein the tethering device defines a hinge angle relative to the leading edge of the superstructure and is configured to be gripped at one end by an operator when the electric trailer is towed.

[0014] A plurality of wheels are connected to the base platform, wherein one or more of the wheels are driven wheels;

[0015] An electric motor operatively connected to the driven wheel and configured to transmit drive torque to the driven wheel in response to a motor control signal, the motor control signal including at least the desired yaw rate and desired ground speed of the electric trailer.

[0016] A sensor suite, comprising a speed sensor, an angle sensor, and a length sensor, wherein the speed sensor, angle sensor, and length sensor are respectively configured to determine the actual ground speed of the electric trailer, the articulation angle, and the length of the tethering device; and

[0017] An electronic controller, which communicates with the sensor suite and is configured to generate motor control signals using proportional-integral-derivative (PID) control logic in response to input signals including the actual ground speed, the articulation angle, and the length, the PID control logic having coupled lateral and longitudinal dynamic control loops that determine the desired yaw rate and desired ground speed of the electric trailer, respectively, to accommodate the movement applied to the tethering device by the operator.

[0018] 2. The electric trailer according to Scheme 1, wherein the length sensor is integrated with the tethering device and includes a string potentiometer.

[0019] 3. The electric trailer according to claim 1, wherein the driven drive wheel includes a pair of front drive wheels, and the electric motor includes a first electric motor and a second electric motor, the first electric motor and the second electric motor being respectively connected to different front drive wheels in the front drive wheel to provide differential steering capability to the electric trailer.

[0020] 4. The electric trailer according to claim 3, wherein the sensor suite includes a first speed sensor and a second speed sensor, the first speed sensor and the second speed sensor being coupled to a corresponding electric motor of the first electric motor and the second electric motor and configured to measure the corresponding wheel speeds of the first electric motor and the second electric motor, and wherein the electronic controller is configured to use the wheel speeds to calculate the ground speed of the electric trailer.

[0021] 5. The electric trailer according to Scheme 1, wherein the lateral control PID loop is configured to calculate the angle error value as the difference between the articulation angle setpoint and the articulation angle measured by the angle sensor, and to use the angle error value to calculate the desired yaw rate.

[0022] 6. The electric trailer according to Scheme 5, wherein the lateral control PID loop is configured to calculate the sine of the angle error value, calculate the product of the sine of the angle error value and a numerical gain value selected from a lookup table based on the length of the tethering device, and use the product to calculate the desired yaw rate.

[0023] 7. The electric trailer according to Scheme 1, wherein the longitudinal control PID loop is configured to calculate the length error value as the difference between the desired distance setpoint and the length measured by the length sensor, and to use the length error value to calculate the desired ground speed.

[0024] 8. The electric trailer according to claim 7, wherein the longitudinal control PID loop is configured to apply a gain to the ground speed to calculate the gain-adjusted ground speed, and to calculate the desired ground speed in part by adding the length error value to the gain-adjusted ground speed.

[0025] 9. The electric trailer according to claim 1, wherein the sensor suite includes a yaw rate sensor configured to measure the actual yaw rate, and the longitudinal control PID loop is configured to limit the ground speed of the electric trailer as an initial speed limit based on the actual yaw rate and the current torque capability of the electric motor.

[0026] 10. A method for controlling an electric pallet, the electric pallet having a superstructure mounted on or integrally formed with a base platform, and a tethering device connected to the superstructure, wherein the tethering device defines a hinge angle relative to a leading edge of the superstructure and is configured to be gripped at one end by an operator when the electric pallet is towed, the method comprising:

[0027] A set of input signals is determined, including measuring the actual ground speed of the electric trailer, the hinge angle between the tethering device and the leading edge of the superstructure, and the length of the electric trailer;

[0028] In response to the input signal, a set of motor control signals is generated using the proportional-integral-derivative (PID) control logic of the electronic controller. This PID control logic has a lateral dynamic control loop connected to the longitudinal dynamic control loop, the lateral and longitudinal dynamic control loops determining the desired yaw rate and desired ground speed of the electric trailer, respectively.

[0029] In response to the desired yaw rate and the desired ground speed, a set of motor control signals are transmitted to electric motors connected to two or more driven wheels of the electric trailer, thereby causing the electric motors to provide drive torque to the driven wheels, thus adapting to the movement applied to the tethering device by the operator.

[0030] 11. The method according to claim 10, wherein determining the input signal comprises: measuring the length of the tethering device using a string potentiometer integrated with the tethering device, wherein the length sensor includes the string potentiometer.

[0031] 12. The method according to claim 10, wherein transmitting the set of motor control signals to the electric motor comprises: transmitting the set of motor control signals to a first electric motor and a second electric motor respectively connected to different driven wheels in the driven wheels, so as to use the different torques and / or speeds of the first electric motor and the second electric motor to enable differential steering of the electric trailer.

[0032] 13. The method according to Scheme 12, comprising a first speed sensor and a second speed sensor connected to corresponding electric motors in the first electric motor and the second electric motor, wherein measuring the set of input signals includes measuring the corresponding wheel speeds of the first electric motor and the second electric motor, the method further comprising: calculating the ground speed of the electric trailer using the corresponding wheel speeds.

[0033] 14. The method according to claim 10 further includes: using the lateral control PID loop to calculate an angle error value as the difference between the hinge angle setpoint and the hinge angle measured by the angle sensor, and using the angle error value to calculate the desired yaw rate via the electronic controller.

[0034] 15. The method according to claim 14 further includes: calculating the sine of the angle error value via the lateral control PID loop, calculating the product of the sine of the angle error value and a numerical gain value selected from a lookup table based on the length of the tethering device, and calculating the desired yaw rate using the product of the sine of the angle error value and the numerical gain value.

[0035] 16. The method according to claim 10 further includes: calculating a length error value as the difference between the desired distance setpoint and the length measured by the length sensor via the longitudinal control PID loop, and then using the length error value to calculate the desired ground speed.

[0036] 17. The method according to claim 16 further includes: applying a gain to the ground velocity via the longitudinal control PID loop to calculate the gain-adjusted ground velocity, and thereafter calculating the desired ground velocity in part by adding the length error value to the gain-adjusted ground velocity.

[0037] 18. The method according to Scheme 10 further includes:

[0038] The actual yaw rate of the electric trailer was measured using a yaw rate sensor; and

[0039] Based on the actual yaw rate and current torque capability of the at least one electric motor, the ground speed of the electric trailer is limited via the longitudinal control PID loop as an initial speed limit.

[0040] 19. An electronic controller for an electric pallet, the electric pallet having a superstructure connected to a base platform, one or more driven wheels connected to the base platform, and at least one electric motor connected to the one or more driven wheels, the electronic controller comprising:

[0041] Processor; and

[0042] A tangible non-transient memory, on which instructions are recorded for controlling the movement of the electric trailer when it is towed by an operator via a tethering device, wherein execution of the instructions by the processor causes the processor to perform the following operations:

[0043] Receive input signals, the input signals including the actual ground speed of the electric trailer measured by the speed sensor, angle sensor and length sensor respectively, the hinge angle between the tethering device and the leading edge of the electric trailer, and the length of the tethering device;

[0044] The electronic controller uses proportional-integral-derivative (PID) control logic to generate a set of motor control signals in response to the input signal. The PID control logic has a lateral dynamic control loop connected to the longitudinal dynamic control loop. The lateral and longitudinal dynamic control loops determine the desired yaw rate and desired ground speed of the electric trailer, respectively.

[0045] The set of motor control signals are transmitted to the at least one electric motor so that the one or more electric motors drive the one or more driven wheels of the electric trailer, thereby adapting to the movement applied to the tethering device by the operator.

[0046] 20. The electronic controller according to claim 19, wherein the longitudinal control PID loop is configured to calculate the length error value as the difference between the desired distance setpoint and the length measured by the length sensor, and to calculate the desired ground speed using the length error value.

[0047] The foregoing features and advantages, as well as other features and accompanying advantages, of this disclosure will become apparent from the following detailed description of illustrative examples and models for implementing this disclosure, in conjunction with the accompanying drawings and appended claims. Furthermore, this disclosure expressly includes combinations and sub-combinations of the elements and features presented above and below. Attached Figure Description

[0048] Figure 1 This is a side view of a representative motor-driven electric pallet configured and controlled according to this disclosure.

[0049] Figure 2 It can be used as Figure 1 A schematic diagram of the powertrain of a portion of the electric trailer shown.

[0050] Figure 3A , 3B And 3C showed Figure 1 The image shows three exemplary motion trajectories of the electric trailer.

[0051] Figure 4 yes Figure 1 A schematic diagram of the representative kinematics of the electric trailer shown.

[0052] Figure 5 An electronic controller and an associated electric trailer are shown. The electronic controller communicates with other components of the electric trailer and is configured to execute this control method.

[0053] Figure 6 It is used for Figure 1 The top-level control diagram of the longitudinal and lateral proportional-integral (PI) controllers connected on a representative electric trailer.

[0054] Figure 7 and 8 It is suitable for Figure 6 A schematic diagram of representative control logic that implements horizontal and vertical control actions within the framework. Detailed Implementation

[0055] This disclosure allows for many different forms of embodiments. Representative examples of this disclosure are shown in the accompanying drawings and are described in detail herein as non-limiting examples of the disclosed principles. Therefore, elements and limitations described in the abstract, background, summary, and detailed description sections but not expressly set forth in the claims should not be incorporated into the claims, individually or collectively, by implication, inference, or otherwise.

[0056] For the purposes of this specification, unless specifically waived, the use of the singular includes the plural, and vice versa; the terms “and” and “or” should be conjunctive and disjunctive; “any” and “all” mean “any and all”; and the words “including,” “contains,” “comprising,” “containing,” “having,” etc., should mean “including but not limited to.” Furthermore, approximate terms such as “approximately,” “almost,” “substantially,” “generally,” “roughly,” etc., may be used herein to indicate “within, almost, or nearly within,” or “within the range of 0-5%,” or “within acceptable manufacturing tolerances,” or logical combinations thereof.

[0057] Referring to the accompanying drawings, in which the same reference numerals denote the same features in multiple views, and from Figure 1 The workspace 10 is shown, in which a motor-driven electric pallet 12 is gently secured to an operator 14 via a flexible tethering device 25. The electric pallet 12 can be used in various facilities, such as, but not limited to, manufacturing plants, warehouses, supply stations, and schools, to assist the operator 14 in transporting loads within the workspace 10. Depending on the nature of the workspace 10 and the nature of the various operations performed therein, the loads transported by the electric pallet 12 can have various sizes, shapes, and structures, such as products, goods, raw materials, partially or fully assembled components or parts, food, beverages or other consumables, mail, parcels, or other such items that may need to be moved within the workspace 10.

[0058] To function in this manner, the electric trailer 12 is equipped with an onboard electronic controller (C) 50. The electronic controller 50 is mounted or housed within the superstructure 13. The superstructure 13 may vary in its configuration based on the load being transported, but is generally embodied as a box-like container, which may include shelves, supports, boxes, or other suitable structures for securely moving the load through the workspace 10. The superstructure 13 is connected to or integrally formed with a base platform 20, which is, for example, a solid plate or flat surface of metal, plastic, and / or composite material, configured to support the combined weight of the electronic controller 50 and the aforementioned load. The base platform 20 is, for example, connected to one or more wheels 22F and 22R via a drive shaft and suspension system (not shown).

[0059] exist Figure 1 In a representative use case, operator 14 grasps the handle 25H of the tethering device 25 in operator's hand 14H, which is pivotally and / or rotatably connected to the superstructure 13. As operator 14 walks through the workspace 10, operator 14 pulls or tows the electric trailer 12 in the general direction of arrow AA. (From arrow F...) T The traction force applied by the operator 14 is thus applied to the electric trailer 12, causing the electric trailer 12 to move relative to the floor surface 11. Depending on the relative speed of the operator 14 and the electric trailer 12 relative to the floor surface 11, the tethering device 25 can extend or retract in length, such as... Figure 1 This is indicated by the double-headed arrow DD. Simultaneously, the electronic controller 50 commands the motor assist force (arrow F) by transmitting the motor drive torque to one or more wheels 22F and / or 22R. M This is done by sending a motor control signal (arrow CC) to move the electric trailer 12. OThe action is transmitted from the electronic controller 50 to a corresponding motor control processor, such as those known in the art, in response to the input signal (arrow CC). I The motor control signal (arrow CC) is executed. As explained in more detail below, within the scope of this disclosure... O This includes at least the expected yaw rate (ω) of the electric trailer. des ) and desired ground velocity (V des For further reference, see below. Figure 6-8 What is described.

[0060] Brief Reference Figure 2 Wheels 22F may include corresponding first and second wheels 22A and 22B, for example, arranged to serve as opposing front wheels of the electric trailer 12 when the electric trailer 12 is towed by the operator 14 in the direction of arrow AA. In this configuration, the powertrain system 30 may include a multi-battery pack (B... HV ) 32, which in a representative configuration can be configured as a rechargeable multi-cell battery pack with lithium-ion or other suitable battery chemistry. Figure 2 The powertrain system 30 also includes first and second electric motors (M) respectively connected to the first and second electric motors (M A ) 36A and (M B The first and second traction power inverter modules (TPIM) of the 36B A ) 34A and (TPIM B 34B.

[0061] When electric motors 36A and 36B are implemented as AC / multiphase traction motors as shown in the figure, TPIMs 34A and 34B are connected to the battery pack 32 via DC voltage bus 33. TPIMs 34A and 34B are also connected to electric motors 36A and 36B via corresponding AC voltage buses 35A and 35B, respectively. In this representative configuration, the internal switching operation of TPIMs 34A and / or 34B is used to convert the DC voltage (VDC) present on DC voltage bus 33 into AC voltage (VAC) on AC voltage buses 35A and / or 35B as needed to electrically excite one or both of electric motors 36A and 36B. Embodiments in which electric motors 36A and 36B are DC motors are also conceivable, in which case TPIMs 34A and 34B and the associated power conversion circuitry can be omitted.

[0062] about Figure 1 The movement of the electric trailer 12, each wheel 22A and 22B can be caused by its respective output torque (i.e., arrow T). A and T B Each provides power. In this configuration, Figure 1The electric trailer 12 can employ differential steering, which is achieved by rotating wheels 22A and 22B via corresponding output members 37A and 37B at different torques or speeds relative to each other. The electronic controller 50 receives input signals (arrow CC) from a sensor suite 40S comprising a length sensor 40, an angle sensor 42, and a speed sensor 44 as described below. I For example, when making a left turn, the electronic controller 50 can command the output torque (T) from the electric motor 36A. A ) is at a higher level than the output torque (T) from the electric motor 36B B A higher level. As those skilled in the art will understand, similar steering effects can be achieved using a single electric motor 36A or 36B and with an associated electronic differential, therefore Figure 2 The configuration shown represents only one possible embodiment of the powertrain system 30.

[0063] Refer again Figure 1 And as described in detail herein with reference to Figures 3-8, the electronic controller 50 is configured to respond to an input signal (arrow CC). I Generate motor control signals (arrow CC) O The electronic controller 50 employs a coupled proportional-integral-derivative (PID) control architecture to achieve this, in which a lateral control PID is coupled with a longitudinal control PID to control the movement of the electric trailer 12 when the operator 14 acts on the electric trailer via the tethering device 25. The resulting movement of the electric trailer 12 can vary depending on the specific manner in which the operator 14 acts on the tethering device 25, for example, whether the operator 14 swings his or her arm or keeps his or her arm steady, and whether the operator 14 makes a sharp turn or walks in a straight line. The possible movements of the operator 14 can impose different dynamic inputs on the electric trailer 12, and therefore different control actions will be required according to this teaching.

[0064] Figure 3A , 3BFigures 3C and 3C illustrate such an exemplary trajectory of movement of the electric trailer 12 when acted upon by operator 14 via tethering device 25. In a contemplated embodiment, tethering device 25 may be a flexible telescopic mechanism having a proximal end 25-1 terminating at a proximal end 25-E, where "proximal end" is relative to the position of operator 14. As shown, proximal end 25-1 may be surrounded by distal end 25-2 such that proximal end 25-1 may extend from distal end 25-2 when operator 14 pulls or actuates proximal end 25-1 in the direction of arrow AA while towing the electric trailer 12. Similarly, proximal end 25-1 is received within distal end 25-2 when operator 14 moves slower than the electric trailer 12 or when operator 14 pushes proximal end 25-1 to prevent forward movement of the electric trailer 12. As an integral part of the tethering device 25, or alternatively as an additional component, the length sensor 40 measures and reports the deployment length of the tethering device 25 for use in [the following context is missing from the original text] Figure 1 The electronic controller 50 controls the movement of the electric trailer 12.

[0065] Figure 3A The diagram illustrates the "linear" movement of the electric trailer 12. In the simplified plan view, the electric trailer 12 is rectangular in shape, with a leading edge 12L and a trailing edge 12T. The operator 14 grips the proximal end 25E of the tethering device 25 in hand 14H and walks with a steady stride in the general direction of arrow AA. When this occurs, the electronic controller 50 adjusts the corresponding output torque (T) of the electric motors 36A and 36B. A and T B The output torque is transmitted to the corresponding wheels 22A and 22B, which serve as the front wheels 22F in this arrangement. In a possible front-wheel drive embodiment, the rear wheels 22R (i.e., 22C and 22D) are freewheeling devices, such as casters located near the rear edge 12T of the electric trailer 12. In this way, the electronic controller 50 ensures that the electric trailer 12 follows the operator 14 at a specific following distance.

[0066] When operator 14 begins to turn, such as Figure 3B As indicated by arrow BB, this is done without any hand movement or noticeable arm swinging. Figure 1 The electronic controller 50 is based on the following distance and the distance at the distal end 25D of the tethering device 25 and the electric trailer 12 (e.g., its superstructure 13 (see below)). Figure 1The hinge angle between the tethering device 25 and the leading edge 12L is measured to allow the electric trailer 12 to follow the operator 14. This angle, referred to below as the hinge angle and abbreviated as θ, is measured by an angle sensor 42 positioned between the tethering device 25 and the leading edge 12L. The hinge angle (θ) is then reported to the electronic controller 50 via a suitable hardwired conductor or wireless connection (e.g., short-range Bluetooth BLUETOOTH®, Wi-Fi, or Near Field Communication (NFC) link). Additional control actions are taken to compensate for operator 14's hand movements and / or arm swings to prevent unintentional jackknifing or tipping of the electric trailer 12, such as... Figure 3C As indicated by arrow CC. Therefore, the electronic controller 50 is notified in real time of the aforementioned length of the tethering device 25 and the measured hinge angle (θ) within the possible range of actions and movements of the operator 14.

[0067] Electric Trailer Kinematics: A Brief Reference Figure 4 Kinematic graph 48 shows the effect of this control strategy when it is executed. Figure 1 and 2 The relevant parameters considered by the electronic controller 50. The electric trailer 12, shown in a plan view in a nominal two-dimensional Cartesian xy coordinate system and having a longitudinal centerline YY, includes two powered wheels 22A and 22B, which are separated from each other by a distance (d). Therefore, the distance between a given wheel 22A or 22B and the centerline YY is d / 2. Casters or unpowered / passive wheels can be used for the remaining wheels 22C and 22D, which, as described above, have corresponding velocity components V. 22C and V 22D .exist Figure 4 In the representative orientation, wheels 22A and 22B are powered by the right motor and the left motor, respectively (i.e., Figure 2 The electric motors 36A and 36B provide power, where "right" and "left" are relative to the nominal forward-facing drive position of the operator 14. Therefore, arrow V... LM and V RM These represent the corresponding motor speeds, which are combined to produce the linear speed (V) of the electric trailer 12. 12 The electric trailer 12 may also have a yaw rate (ω) with respect to the instantaneous center of rotation (ICR) of a point in free space, as understood in the art.

[0068] Continuing to refer to representative figure 48, the speed (V) of electric trailer 12. 12 This can be mathematically represented as , while yaw rate .in addition:

[0069]

[0070] Finally, the speeds of the left and right motors (i.e., electric motors 36A and 36B) are expressed as speeds (V). 12 A function of yaw rate (ω) and distance (d) between wheels 22A and 22B:

[0071]

[0072]

[0073] therefore, Figure 4 The kinematic diagram 48 illustrates a specific configuration of the electric trailer 12, in which, in an exemplary instance, forward steering is achieved via the differential speed of wheels 22A and 22B. Within the scope of this disclosure, other embodiments using different forms of kinematic diagram 48 are conceivable, such as embodiments where wheels 22A and 22B are steerable using steering components. Figure 4 The illustration is intended to illustrate only one possible implementation.

[0074] Now for reference Figure 5 The text further describes the actions of operator 14 towing electric trailer 12, wherein electric trailer 12 is transported via... Figure 2 The electric motors 36A and 36B, and the corresponding wheels 22A and 22B, provide at least some of the necessary prime mover power. As described above, the electronic controller 50 is powered by input signals (arrow CC). I The input signal includes two measurements from the tethering device 25: (i) the hinge angle (θ) measured and output by the angle sensor 42, which describes the angular orientation of the tethering device 25 relative to the leading edge 12L of the electric trailer 12, or more precisely, the longitudinal center axis YY and the longitudinal center axis A of the tethering device 25. 25 (ii) the angle between; and (ii) the length (L) of the tethering device 25 as measured and reported by the length sensor 40 disposed within the tethering device 25.

[0075] In a possible configuration, angle sensor 42 may include a rotary position sensor, such as a resolver or encoder, capable of outputting an articulation angle (θ) as an electrical signal that can be interpreted as an angle value by electronic controller 50. For example, angle sensor 42 may output a sine or cosine waveform as understood in the art, wherein electronic controller 50 is configured to track and interpret such a signal as a corresponding angle value. Length sensor 40 itself may be implemented as a string potentiometer or other suitable linear position sensor, similarly capable of outputting length (L) as an electrical signal that can be interpreted by electronic controller 50 as a linear distance between operator 14 and the leading edge 12L of electric trailer 12.

[0076] In order to execute, now will refer to Figure 6 ,7 The electronic controller 50, programmed with control logic 50L, is equipped with a dedicated number of volatile and non-volatile memories (M) and one or more processors (P) for various motion control functions of the corresponding method described in 8. The memories (M) include or are configured as non-transient computer-readable storage devices or media, and may include volatile and non-volatile storage devices in read-only memory (ROM) and random access memory (RAM), and may include keep-alive memory (KAM) or other persistent or non-volatile memory for storing various operating parameters when the processor (P) is powered off. Other embodiments of the memories (M) may include, for example, flash memory, solid-state memory, PROM (programmable read-only memory), EPROM (electrical PROM) and / or EEPROM (electrically erasable PROM), and other electrical, magnetic, and / or optical memory devices capable of storing data, at least some of which are used to perform method 100. The processor (P) may include various microprocessors or central processing units, as well as associated hardware such as digital clocks or oscillators, input / output (I / O) circuits, buffer circuits, application-specific integrated circuits (ASICs), system-on-a-chip (SoCs), electronic circuits, and other necessary hardware required to provide programming functionality. In the context of this disclosure, the electronic controller 50 executes instructions via the processor (P) to cause the electronic controller 50 to perform this method.

[0077] The computer-readable, non-transitory instructions or code that implement this method and are executable by the electronic controller 50 may include one or more separate software programs, each of which may include an ordered list of executable instructions for implementing the logical functions described below. During operation of the electric trailer 12, the processor (P) executes the instructions, causing the electronic controller 50 to adjust the movement of the electric trailer 12 as the operator 14 pulls it.

[0078] Figure 6 A schematic top-level implementation of control logic 50L is described in particular. See below for reference... Figure 7 and 8 The lateral and longitudinal control portions of control logic 50L are discussed. As mentioned above, the exemplary solution proposed herein combines the longitudinal and lateral control of the electric trailer 12 into a single control loop for tighter matching. Figure 1 The operator 14’s natural movement and arm swinging motions are ultimately aimed at optimizing the motion and stability performance of the electric trailer 12. Figure 6 The control logic 50L shown can be encoded or programmed into computer-readable instructions, which can be generated by... Figure 1 , 2The electronic controller 50 of the 5th generation performs actions to optimize the motion stability and smoothness of the electric trailer 12, regardless of the actions of the operator 14. The method corrects the yaw of the electric trailer 12 based on a nonlinear function of the speed of the electric trailer 12 and the measured length (L) of the tethering device 25.

[0079] Figure 6 The control logic 50L includes a lateral dynamic control block (“LAT-CC”) 100 and a longitudinal dynamic control block (“LONG-CC”) 200, where “block” refers to a collection of software or algorithm-based control functions that manage the dynamic control of the electric trailer 12. Both blocks 100 and 200 receive commands from the controller. Figure 2 The corresponding angle sensor 42 and length sensor 40 depicted measure the aforementioned hinge angle (θ) and the length (L) of the tethering device 25. Additional inputs to blocks 100 and 200 include the actual yaw rate (ω) and the actual speed (V). 12 That is, the calculated or measured ground speed of the electric trailer 12, wherein the actual yaw rate (ω) and the actual trailer speed (V) 12 The lateral and longitudinal dynamic states of the electric trailer 12 are described respectively.

[0080] In a specific, non-restrictive example, the actual velocity (V) 12 This can be determined as follows: for example, by using wheel speed sensor 44 to measure the rotational speed of driven wheels 22A and 22B, and then according to the above reference. Figure 4 The velocity (V) was calculated from the values ​​described in kinematic graph 48. 12 In this embodiment, wheels 22C and 22D are passive free-gliding devices, i.e., not powered by their respective prime movers. Although the actual yaw rate (ω) can be measured using an optional yaw rate sensor 46 (e.g., an inertial measurement unit), the actual yaw rate (ω) can, in an alternative, be calculated in real time based on the rate of change of the measured articulation angle (θ) as described above and understood in the art, or calculated using wheel speed sensors and a kinematic model of the electric trailer 12 (e.g., kinematic graph 48).

[0081] Figure 7 and 8 Exemplary embodiments of lateral and longitudinal dynamic control blocks 100 and 200 are shown, which handle the actual yaw rate (ω) and the speed (V) of the electric trailer 12, respectively. 12 ), hinge angle (θ) and length (L), wherein the electronic controller 50 uses Figure 2 The processor (P) shown is used for processing. Afterwards, Figure 6 The lateral dynamic control block 100 outputs the desired trailer yaw rate (ω).des Simultaneously, the longitudinal control block 200 outputs the desired speed (V). des ). Then, by switching the control operation of TPIM 34A and / or 34B and to Figure 2 The electric motors 36A and 36B shown are powered by an electronic controller 50 that modifies the output torque / speed of the electric motors 36A and 36B to produce the desired lateral and longitudinal dynamic response.

[0082] Lateral control: Reference Figure 7 , Figure 6 The lateral dynamic control logic block 100 can be implemented as a proportional-integral-derivative (PID) loop as shown. Starting from logic block B102, Figure 5 The electronic controller 50 controls the aforementioned actual speed (V) 12 Square the value and convert it to a whole. The output is sent to the first gain logic block B104. The purpose of performing this function in block B102 is to ensure that the subsequent numerical gain applied at logic block B104 is non-linear. Therefore, other non-linear functions can be applied to logic block B104 without departing from the scope of this invention.

[0083] The first logic gain block B104 needs to determine the numerical gain value (G1) to be applied based on the value from logic block B102. For example, the electronic controller 50 can access the calibration lookup table (“G1 TBL”) from its resident memory (M) and then retrieve the value. The corresponding numerical gain value (G1) is then fed to the multiplier logic block B106. In the described implementation, this numerical gain value can be in units of the reciprocal of a second (i.e., 1 / s).

[0084] Block B105A (“DET θ) des ") It is necessary to determine the angular reference or setpoint value of the hinge angle. For increased clarity, in" Figure 7 This value is represented as (θ) des Set point value (θ) des Then it is transmitted to the angle error calculation block B109.

[0085] In block B105B (“MEAS θ”), use Figure 2 The angle sensor 42 shown above is used to measure the hinge angle (θ). The measured hinge angle (θ) (e.g., in radians) is then fed to the error calculation block B109.

[0086] In block B106, the error value (E) in radians comes from the error calculation block B109. θ(θ) is multiplied by the numerical gain value (G1) from logic block B104. Therefore, in this embodiment, the product (i.e., (G1)(θ)) is in radians per second (rad / s), and this product is transmitted to the summation logic block B116 as described below.

[0087] Logic block B108 (“MEAS L”) requires measurement Figure 1 The length (L) of the tethering device 25 shown. This measurement can be made by a length sensor 40 (see...). Figure 2 As described above, the length sensor is integrated with or attached to the tethering device 25. The measured length (L) is then transmitted to the second gain logic block B111 for processing.

[0088] Still referencing Figure 7 Error calculation block B109 is used to calculate the angle setpoint value (θ) from logic block B105A. des The difference between the measured hinge angle (θ) and the measured hinge angle from logic block B105B is then output by block B109 as an angle error value in radians (E). θ In the context of the lateral dynamic control logic block 100, the angle error value (E) θ It is transmitted to blocks B106, B110, and B114.

[0089] Block B110 needs to determine the geometric sine (E) of the error value. θ ), i.e., sin (θ). As understood in the art, block B110 can alternatively be defined according to the error value (E). θ The cosine is calculated in the same way as the error value (E), so block B110 can instead calculate the error value (E). θ The cosine of θ is then calculated, and the calculated value, in this example, is sin(θ), which is fed into multiplier block B112.

[0090] The second gain block B111, operating similarly to the first gain block B104 described above, needs to determine the numerical gain value (G2) to be applied based on the measured length (L) from the tethering device 25 of logic block B108. For example, for a length (L) in meters (m), the calibration lookup table (G2 TBL) can be filled with a calibration gain value having units (1 / (m·s)), which will output the gain (G2) in the reciprocal of a second (i.e., 1 / s). The gain (G2) is then fed to the multiplier block B112.

[0091] Block B112 is used to multiply the outputs of blocks B110 and B111. The product G2·sin(θ) is the initial desired yaw rate (ω) in rad / s. des_iIt is then fed into summation block B116 for further processing.

[0092] Figure 7 Block B114 (“PID-LAT”) of the lateral dynamic control block 100 shown receives the angle error value (E) from logic block B109 as described above. θ Then apply the proportional gain. The output of block B114 is the yaw rate error (ω). E The value can be expressed in radians per second. Then, the yaw rate error (ω) is calculated. E Provided to summation block B116.

[0093] In summation block B116, the electronic controller 50 then adds the outputs of logic blocks B106, B112, and B114 to determine the desired yaw rate (ω). des ). After that, Figure 1 and 2 The electronic controller 50 uses the desired yaw rate (ω) des )as well as Figure 8 Expected speed (V) des ), to adjust the commanded output torque or speed of electric motors 36A and 36B in the overall motion control of electric trailer 12.

[0094] Vertical control: now refer to Figure 8 , Figure 6 The vertical control logic block 200 shown in the top-level view can be implemented as another PID loop as shown. From block B202 (“DETω A ") Start, controller 50 determines the actual yaw rate (ω) of electric trailer 12. A As mentioned above, this action may require direct measurement via an inertial measurement unit or another suitable yaw rate sensor 46, such as... Figure 6 As shown, or the actual yaw rate (ω) A The actual yaw rate (ω) can be calculated in real time by the electronic controller 50. A It is fed into the maximum speed logic block ("DETV") LIM B204 is used for further processing.

[0095] Figure 8 Block B204 needs to be based on Figure 2 The maximum speed (V) of each of the electric motors 36A and 36B is determined based on the current torque capability of each (i.e., based on existing current, voltage, temperature, or other hardware limitations understood in the art). LIM For example, block B204 may include access to the actual yaw rate (ω). A The lookup table is indexed or referenced, and then the initial speed limit (V) is returned.LIM The purpose of block B204 is to prevent instability or overturning of the electric trailer 12 by enforcing a maximum speed, in which case the maximum speed is determined by... Figure 2 The wheels 22A and 22B provide the electric trailer 12 with a forward ground speed (V) 12 Then the initial velocity limit (V) LIM The speed (V) of the electric trailer 12 relative to the ground is fed to logic block B216. As described above, the speed (V) of the electric trailer 12 relative to the ground is... 12 Ultimately by Figure 2 The corresponding rotational speeds of electric motors 36A and 36B are determined.

[0096] In logic block B206 (“DET D”) des "), Electronic controller 50 determined Figure 1 The desired distance (D) between the operator 14 and the electric trailer 12 shown. des This value can be determined through calibration, for example, as a calibration setpoint. Then, the desired distance (D) from block B206 will be... des The data is fed into the error calculation block B211.

[0097] Figure 8 Block B208 (“MEAS L”) includes a measurement of the current length (L) of the aforementioned tethering device 25. For example... Figure 6 As best illustrated, block B208 may need to use the length sensor 40 of the tethering device 25 to measure the current axial length of the tethering device 25 and report the measured length (L) to the electronic controller 50. The desired distance (D) from block B206... des Similarly, the length (L) is then fed into the error calculation block B211.

[0098] Continue the discussion Figure 8 A representative embodiment of logic block 200, logic block B210 (“DET V”) 12 This includes determining the actual ground speed (V) of the electric trailer 12 described herein. 12 When using, such as Figure 6 When the individual wheel speed sensors 44 are present on wheels 22A and 22B, logic block B210 may include using the individually reported wheel speeds to calculate the ground speed (V) of the electric trailer 12. 12 ), as understood in the art. Then, for example, the actual ground velocity (V) in meters per second (m / s). 12 It is provided to the numerical gain block B212 for further processing.

[0099] In block B211, electronic controller 50 calculates the desired distance (D). desThe difference between the setpoint (i.e., the length from block B206) and the measured length (L) provided by length sensor 40 in block B208. The result is the length error (E) in meters (m). L This is fed into the PID logic block B214 for further processing, as described below.

[0100] The numerical gain block B212 used by the electronic controller 50 may include a calibration gain table (G3 TBL) stored in memory (M). In this embodiment, block B212 includes extracting the corresponding gain value. Actual ground velocity (V 12 Multiply by the gain value (G3), the product is the modified velocity value (VG3) in m / s fed into the summing block B215.

[0101] Figure 7 The PID block B214 (“PID-LONG”) receives the error value (E) from the logic block B211. L And apply a proportional gain to generate an initial velocity error (V). E Block B214 may include references to the error value (E). L The lookup table is indexed, and the speed error (V) is extracted from it. E (e.g., in m / s). Then provide this value to the summation block B215.

[0102] In summation block B215, the velocity error (V) from block B214 is... E The modified velocity value (VG3) from logic block B212 is added to calculate the initial desired velocity (V). des_i The value is then fed into the speed limiting module B216 for further processing.

[0103] Continue to refer to Figure 7 The speed limit block B216 (“MAX / MIN LIM”) used in this paper is configured to help prevent the electric trailer 12 from tipping over. To prevent tipping, the electronic controller 50 at block B216 receives an initial speed limit (V) from logic block B204. LIM The speed limit block B216 then uses the modified speed value (VG3) from logic block B215. This is based on the desired speed (VG3). des The maximum and minimum limits to be calibrated will be applied to the initial speed limit (V). LIM ). After that, Figure 1 and 2 The electronic controller 50 uses the desired speed (V) des ) and the above references Figure 7 The derived expected yaw rate (ω) des), to adjust the commanded output torque or speed of electric motors 36A and 36B in the overall motion control of electric trailer 12.

[0104] That is, as described above, based on the yaw rate (ω) and the current capabilities of electric motors 36A and 36B, block B204 informs block B216 of the maximum permissible speed of the electric trailer 12. Then, based on the desired speed (V) from summing block B215... des This value is further limited, namely, the initial velocity limit (V). LIM ), where the desired speed (V) des The electronic controller 50 uses the tethering device 25 to measure the length (L) and the desired distance (D). des This is derived from the possible hand and / or arm movements of operator 14, based on the speed and yaw rate of electric trailer 12, the ground speed (V) of electric trailer 12. 12 The electronic controller 50 is tightly regulated. Therefore, the electronic controller 50 is able to maintain stability, thereby preventing the electric trailer 12 from tipping over or bending, while maintaining the desired distance (D). des Appropriate spacing between the captured electric trailer 12 and the operator 14.

[0105] therefore, Figure 6 The control logic 50L, which uses the connected horizontal and vertical dynamic control blocks 100 and 200, can be controlled by... Figure 2 The electronic controller 50 is used to maintain the spacing and stable speed of the electric trailer 12 as detailed above. Examples of lateral and longitudinal dynamic control blocks 100 and 200 are shown in [the original text]. Figure 7 and 8 As shown in the figure. As part of this control strategy, the actual ground speed (V) of the electric trailer 12 is... 12 This can be used to modify the yaw rate command on the electric trailer 12. The speed feedback is used to make the response more robust to the movements of the operator 14, particularly when the operator 14 is towing the electric trailer 12 via the tethering device 25, due to arm swinging or other hand movements exerted by the operator 14. This teaching also envisions limiting the speed (V) based on the current capabilities of the electric motors 36A and 36B. 12 In view of the foregoing disclosure, those skilled in the art will readily understand these and other accompanying benefits.

[0106] Similarly, those skilled in the art will understand that embodiments in which the electronic controller 50 is configured to perform the method 100 described above can be envisioned. For example, the electronic controller 50 may include, for instance, […]. Figure 1 and 2The diagram shows one or more processors (P) and a tangible non-transient memory (M) on which instructions are recorded for controlling the movement of the electric trailer 12 when the operator 14 pulls the electric trailer 12 via the tethering device 25. In this embodiment, the execution of instructions by the processor (P) causes the processor (P) to receive an input signal (arrow CC). I The input signal includes the actual ground speed (V) of the electric trailer 12 measured by the speed sensor 44, angle sensor 42, and length sensor 40, respectively. 12 ), tethering device 25 and the leading edge 12L of electric trailer 12 (e.g., as Figure 1 The hinge angle (θ) between its upper structure 13) and the length (L) of the fastening device 25 are shown.

[0107] In this embodiment, the execution of the instruction causes the processor (P) to respond to the input signal (arrow CC). I )use Figure 6 The PID control logic 50L generates a set of motor control signals (arrow CC). O The PID control logic 50L has a lateral dynamic control loop 100 connected to the longitudinal dynamic control loop 200. The lateral dynamic control loop and the longitudinal dynamic control loop respectively determine the desired yaw rate (ω) of the electric trailer 12. des ) and desired ground velocity (V des The execution of the instruction also causes the electronic controller 50 to send the group of motor control signals (arrow CC). O Transmitted to Figure 2 Electric motors 36A and / or 36B are used to power the driven wheels 22A and / or 22B of the electric trailer 12, thereby adapting to the movement applied to the tethering device 25 by the operator.

[0108] The detailed description and accompanying drawings or figures support and describe the present teachings, but the scope of the present teachings is defined only by the claims. While some best modes and other embodiments for carrying out the present teachings have been described in detail, various alternative designs and embodiments exist for practicing the present teachings as defined in the appended claims. Furthermore, this disclosure expressly includes combinations and sub-combinations of the elements and features presented above and below.

Claims

1. An electric trailer, comprising: A base platform having an upper structure mounted thereon or integrally formed therewith; A tethering device is attached to the superstructure, wherein the tethering device defines a hinge angle relative to the leading edge of the superstructure and is configured to be gripped at one end by an operator when the electric trailer is towed. A plurality of wheels are connected to the base platform, wherein one or more of the wheels are driven wheels; An electric motor, operatively connected to the driven wheel and configured to transmit drive torque to the driven wheel in response to a motor control signal, the motor control signal including at least the desired yaw rate and desired ground speed of the electric trailer; A sensor kit, comprising a speed sensor, an angle sensor, and a length sensor, wherein the speed sensor, angle sensor, and length sensor are respectively configured to determine the actual ground speed of the electric trailer, the articulation angle, and the length of the tethering device; as well as An electronic controller, communicating with the sensor suite and configured to generate motor control signals using proportional-integral-derivative (PID) control logic in response to input signals including the actual ground velocity, the articulation angle, and the length, the PID control logic having coupled lateral and longitudinal dynamic control loops that determine the desired yaw rate and desired ground velocity of the electric trailer, respectively, to accommodate movements applied to the tethering device by the operator. The lateral dynamic control loop is configured to calculate the angle error value as the difference between the articulation angle setpoint value and the articulation angle measured by the angle sensor, and to use the angle error value to calculate the desired yaw rate. The lateral dynamic control loop is configured to calculate the sine of the angle error value, calculate the product of the sine of the angle error value and a numerical gain value selected from a lookup table based on the length of the tethering device, and use the product to calculate the desired yaw rate.

2. The electric trailer according to claim 1, wherein, The length sensor is integrated with the tethering device and includes a string potentiometer.

3. The electric trailer according to claim 1, wherein, The driven wheels include a pair of front drive wheels, and the electric motor includes a first electric motor and a second electric motor, which are respectively connected to different front drive wheels to provide differential steering capability to the electric trailer.

4. The electric trailer according to claim 3, wherein, The sensor suite includes a first speed sensor and a second speed sensor, which are coupled to a corresponding electric motor in the first electric motor and the second electric motor and are configured to measure the corresponding wheel speeds of the first electric motor and the second electric motor, wherein the electronic controller is configured to use the wheel speeds to calculate the ground speed of the electric trailer.

5. The electric trailer according to claim 1, wherein, The longitudinal dynamic control loop is configured to calculate the length error value as the difference between the desired distance setpoint and the length measured by the length sensor, and to use the length error value to calculate the desired ground velocity.

6. The electric trailer according to claim 5, wherein, The longitudinal dynamic control loop is configured to apply a gain to the actual ground velocity to calculate a modified ground velocity, to determine a velocity error value from a length error value, and to calculate the desired ground velocity by adding the velocity error value to the modified ground velocity.

7. The electric trailer according to claim 1, wherein, The sensor suite includes a yaw rate sensor configured to measure the actual yaw rate, and the longitudinal dynamic control loop is configured to limit the ground speed of the electric trailer as an initial speed limit based on the actual yaw rate and the current torque capability of the electric motor.

8. A method for controlling an electric trailer, the electric trailer having a superstructure mounted on or integrally formed with the base platform, and a tethering device connected to the superstructure, wherein the tethering device defines a hinge angle relative to a leading edge of the superstructure and is configured to be gripped at one end by an operator when the electric trailer is towed, the method comprising: A set of input signals is determined, including measuring the actual ground speed of the electric trailer, the hinge angle between the tethering device and the leading edge of the superstructure, and the length of the tethering device; In response to the input signal, a set of motor control signals is generated using the proportional-integral-derivative (PID) control logic of the electronic controller. This PID control logic has a lateral dynamic control loop connected to the longitudinal dynamic control loop. The lateral and longitudinal dynamic control loops determine the desired yaw rate and desired ground speed of the electric trailer, respectively. In response to the desired yaw rate and the desired ground speed, a set of motor control signals are transmitted to electric motors connected to two or more driven wheels of the electric trailer, thereby causing the electric motors to provide drive torque to the driven wheels, thus adapting to the movement applied to the tethering device by the operator. The method further includes: using the lateral dynamic control loop to calculate an angle error value, which is the difference between the hinge angle setpoint value and the hinge angle measured by the angle sensor; and using the angle error value via the electronic controller to calculate the desired yaw rate; and The method further includes: calculating the sine of the angle error value via the lateral dynamic control loop, calculating the product of the sine of the angle error value and a numerical gain value selected from a lookup table based on the length of the tethering device, and calculating the desired yaw rate using the product of the sine of the angle error value and the numerical gain value.

9. The method according to claim 8, wherein, Determining the input signal includes: measuring the length of the tethering device using a length sensor integrated with the tethering device, wherein the length sensor includes a string potentiometer.

10. The method according to claim 8, wherein, Transmitting the set of motor control signals to the electric motor includes: transmitting the set of motor control signals to a first electric motor and a second electric motor respectively connected to different driven wheels in the driven wheels, so as to use the different torques and / or speeds of the first electric motor and the second electric motor to enable differential steering of the electric trailer.

11. The method of claim 10, comprising a first speed sensor and a second speed sensor coupled to corresponding electric motors in the first electric motor and the second electric motor, wherein measuring the set of input signals includes measuring the corresponding wheel speeds of the first electric motor and the second electric motor, the method further comprising: The ground speed of the electric trailer is calculated using the corresponding wheel speed.

12. The method according to claim 8, further comprising: The longitudinal dynamic control loop calculates a length error value as the difference between the desired distance setpoint and the length measured by the length sensor, and then uses the length error value to calculate the desired ground speed.

13. The method of claim 12, further comprising: A gain is applied to the actual ground velocity via the longitudinal dynamic control loop to calculate a modified ground velocity, thereby determining a velocity error value from the length error value, and then the desired ground velocity is calculated by adding the velocity error value to the modified ground velocity.

14. The method of claim 8, further comprising: The actual yaw rate of the electric trailer was measured using a yaw rate sensor. as well as Based on the actual yaw rate and current torque capability of at least one electric motor, the ground speed of the electric trailer is limited via the longitudinal dynamic control loop as an initial speed limit.

15. An electronic controller for an electric trailer, the electric trailer having a superstructure connected to a base platform, one or more driven wheels connected to the base platform, and at least one electric motor connected to the one or more driven wheels, the electronic controller comprising: processor; as well as A tangible non-transient memory, on which instructions are recorded for controlling the movement of the electric trailer when it is towed by an operator via a tethering device, wherein execution of the instructions by the processor causes the processor to perform the following operations: Receive input signals, the input signals including the actual ground speed of the electric trailer measured by the speed sensor, angle sensor and length sensor respectively, the hinge angle between the tethering device and the leading edge of the electric trailer, and the length of the tethering device; The proportional-integral-derivative (PID) control logic of the electronic controller generates a set of motor control signals in response to the input signal. This PID control logic has a lateral dynamic control loop connected to the longitudinal dynamic control loop. The lateral and longitudinal dynamic control loops respectively determine the desired yaw rate and desired ground speed of the electric trailer. The set of motor control signals is transmitted to the at least one electric motor, causing one or more electric motors to drive the one or more driven wheels of the electric trailer, thereby adapting to the movement applied to the tethering device by the operator. The proportional-integral-derivative control logic is configured as follows: The lateral dynamic control loop is used to calculate an angle error value, which is the difference between the hinge angle setpoint value and the hinge angle measured by the angle sensor, and the angle error value is used to calculate the desired yaw rate; and The sine of the angle error value is calculated via the lateral dynamic control loop, the product of the sine of the angle error value and a numerical gain value selected from a lookup table based on the length of the tethering device is calculated, and the desired yaw rate is calculated using the product of the sine of the angle error value and the numerical gain value.

16. The electronic controller according to claim 15, wherein, The longitudinal dynamic control loop is configured to calculate the length error value as the difference between the desired distance setpoint and the length measured by the length sensor, and to use the length error value to calculate the desired ground speed.

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