A torque balance control method for a guided transport vehicle

Abstract

This invention discloses a torque balance control method for a guided transport vehicle. Force measuring devices are installed on each guide component of the guided transport vehicle, and torque sensors and / or speed sensors are installed on each traveling wheel. By acquiring the force data of the guide components measured by the force measuring devices under the current state of the guided transport vehicle, it is determined whether there is deflection. When deflection occurs, based on the torque balance principle, the output torque of each traveling wheel is controlled according to the deflection torque generated by each guide component. The change in output torque generates a corrective torque, which is used to balance the deflection torque, thereby making the transport vehicle travel smoothly and reducing the wear of the traveling wheels and guide components.

Description

Technical Field

[0001] This invention relates to the field of automated material handling vehicle technology, specifically to a torque balancing system and method for a guided material handling vehicle. Background Technology

[0002] A guided transport vehicle that uses side or bottom guidance and whose wheels travel directly on the ground has guide wheels or guide rollers installed on the vehicle in contact with guide plates or guide grooves installed on the ground and be constrained and subjected to reaction forces from the guide plates or guide grooves. These forces then act on the vehicle body to provide guidance for the guided transport vehicle's flight direction, allowing the guided transport vehicle to travel along the guide plates or guide grooves.

[0003] Due to uneven ground or insufficient friction, guided transport vehicles may experience wheel slippage during operation; or the center of gravity of the goods may deviate significantly from the center of gravity of the guided transport vehicle, resulting in different loads on each drive wheel and significant differences in the output torque of each drive motor. Generally, transport vehicles only control the vehicle speed. In this case, the torque output by each drive wheel is only used for speed adjustment. The different driving forces provided by each drive wheel to the vehicle body cause an imbalance of torque on the center of gravity or center of mass of the vehicle body, causing the vehicle body to tilt to one side. It is necessary to rely on the reaction force of the guide plate or guide groove on the guide wheels or guide rollers installed on the vehicle body to balance the torque on the center of gravity or center of mass of the vehicle body, so that the transport vehicle passively corrects itself and continues to travel along the guide plate or guide groove. When the transport vehicle travels along the guide plate or guide groove, the above process occurs repeatedly due to the lack of corresponding control methods. It may also cause the transport vehicle to always deviate to one side or alternately deviate to both sides due to uneven load, ground or mechanical reasons, resulting in unstable transport vehicle travel. The guide wheels or guide rollers, guide plates or guide grooves, and traveling wheels are subjected to large and uneven forces, causing excessive wear or damage and energy loss. Summary of the Invention

[0004] To address the aforementioned problems, the inventors provide a torque balance control method for a guided transport vehicle. By detecting the force on the guide components, the driving torque or braking torque of each traveling wheel is adjusted, thereby achieving torque balance in the heading direction of the transport vehicle. This makes the transport vehicle travel more smoothly and reduces wear on the traveling components and guide components.

[0005] This invention provides a torque balance control method for a guided transport vehicle. The guided transport vehicle moves along a guide rail, and the guide member on it contacts the guide rail. When the guided transport vehicle deflects, the force exerted by the guide member on the guide rail causes the guide member to be subjected to the reaction force of the guide rail.

[0006] Force measuring devices are installed on each guide component of the guided transport vehicle to measure the force on the guide component;

[0007] A speed sensor and / or torque sensor are installed on each traveling device of the guided transport vehicle. The speed sensor is used to detect the speed of each traveling wheel, and the torque sensor is used to detect the torque on each traveling wheel.

[0008] The sum of the torques of the forces exerted by each guide component on the guide rail on the center or center of mass of the guided transport vehicle forms the deflection torque of the guided transport vehicle's heading; the sum of the torques of the forces exerted by each traveling wheel on the vehicle body on the center or center of mass of the guided transport vehicle forms the correction torque of the guided transport vehicle's heading.

[0009] The method includes:

[0010] Step S1: Obtain the force data of the guide component measured by the force measuring device under the current state of the guided transport vehicle. When the force on the guide component increases abnormally, determine and calculate the deflection torque of the guided transport vehicle.

[0011] Step S2: Based on the principle of torque balance, the output torque or braking torque of each traveling wheel is controlled according to the deflection torque of the guide vehicle, thereby controlling the correction torque of each traveling wheel on the vehicle body, so that the deflection torque and the correction torque reach torque balance, the guide vehicle resumes the predetermined course and travels stably, and the force data of each guide component measured by the force measuring device are balanced or meet expectations.

[0012] Furthermore, the guide includes: a left front guide, a right front guide, a left rear guide, and a right rear guide;

[0013] Left and right orientations refer to the guide components being located on both sides of the longitudinal axis of the guided transport vehicle, while front and rear orientations refer to the guide components being located on both sides of the transverse axis of the guided transport vehicle. The intersection of the longitudinal axis and the transverse axis is the center or centroid of the guided transport vehicle. The positional relationship between the guide component and the center or centroid of the guided transport vehicle is described by using the left and right orientations and the front and rear orientations to jointly position the guide component.

[0014] Step S1 includes: when the guided transport vehicle is traveling longitudinally, if the force measuring device detects that the reaction force on at least one of the guide members in the left or / and right directions increases, based on the direction of the sum of the moments of the forces of each guide member about the center of the vehicle body or the center of mass, it is determined that the guided transport vehicle has deflected to the side of the expected course, and the deflection moment is calculated; or

[0015] When the guided transport vehicle is traveling laterally, the force measuring device detects that the reaction force on at least one of the guide members in the front or / and rear positions increases. Based on the direction of the sum of the moments of the forces of each guide member about the center of the vehicle body or the center of mass, it is determined that the guided transport vehicle has deflected to the side of the expected course, and the deflection moment is calculated.

[0016] Furthermore, the traveling wheel includes: a drive wheel and a support wheel;

[0017] The guide components include: a front guide component and a rear guide component arranged along or parallel to the longitudinal axis of the guided transport vehicle; and a left guide component and a right guide component arranged along or parallel to the transverse axis of the guided transport vehicle.

[0018] Left and right orientations refer to the guide components being located on both sides of the longitudinal axis of the guided transport vehicle, while front and rear orientations refer to the guide components being located on both sides of the transverse axis of the guided transport vehicle. The intersection of the longitudinal axis and the transverse axis is the center or centroid of the guided transport vehicle.

[0019] Step S1 includes: when the guided transport vehicle is traveling longitudinally, if the force measuring device detects that the reaction force on at least one of the front or / and rear guide members increases, based on the direction of the sum of the moments of the forces of each guide member about the center of the vehicle body or the center of mass, it is determined that the guided transport vehicle has deflected to one side of the expected course, and the deflection moment is calculated; or

[0020] When the guided transport vehicle is traveling laterally, the force measuring device detects that the reaction force on at least one of the left or / and right guide members increases. Based on the direction of the sum of the moments of the forces of each guide member about the center of the vehicle body or the center of mass, it determines that the guided transport vehicle has deflected to the side of the expected course and calculates the deflection moment.

[0021] Further, step S2 includes:

[0022] Based on the torque balance, the correction torque is derived from the deflection torque. The correction torque is decomposed into the torque controlling the drive wheel about the center or center of mass of the guide vehicle, increasing the output torque of the drive wheel on the deflection side, increasing its speed, and thus increasing the force of the drive wheel on the vehicle body.

[0023] Alternatively, reduce the output torque of the drive wheel on the opposite side of the deflection to lower its speed, thereby increasing the force exerted by the drive wheel on the opposite side of the deflection on the vehicle body in the opposite direction of travel.

[0024] Alternatively, increase the force exerted by the drive wheel on the deflection side on the vehicle body and increase the force exerted by the drive wheel on the opposite deflection side on the vehicle body in the opposite direction;

[0025] The sum of the torques exerted by each controlled drive wheel on the vehicle body on the center or center of mass of the guided transport vehicle forms the corrective torque.

[0026] Furthermore, the drive wheel and / or support wheel are equipped with a braking device;

[0027] When the guided transport vehicle deflects to one side, a corrective torque is derived from the deflection torque based on torque balance. This corrective torque is decomposed into the torques of the drive wheels and / or support wheels about the center or center of gravity of the guided transport vehicle. A braking torque is applied to the drive wheels and / or support wheels on the opposite side of the deflection through a braking device, reducing their rotational speed and thus increasing the force exerted by the drive wheels on the opposite side of the deflection on the vehicle body in the opposite direction of travel. The sum of the torques of the forces exerted by each braked drive wheel and / or support wheel on the vehicle body in the opposite direction of travel about the center or center of gravity of the guided transport vehicle forms the corrective torque.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] The torque balance control method for the guided transport vehicle provided by this invention, taking into account the unique guiding structure of the guided transport vehicle, uses the force on the guide component as the feedback quantity and the driving torque or braking torque on the traveling wheel as the control quantity to form a closed-loop control. Ultimately, the deflection torque and the correction torque are basically or nearly balanced, the force on each guide component tends to be balanced or reduced, so that the transport vehicle travels smoothly and reduces the wear of the traveling parts and guide components as well as energy loss. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the guided transport vehicle in Example 1;

[0031] Figure 2 This is a schematic diagram of the force analysis of the traveling wheels of the guided transport vehicle in Example 1;

[0032] Figure 3 This is a schematic diagram of torque analysis when the guide vehicle is in torque balance during the forward movement process in Example 1;

[0033] Figure 4 This is a schematic diagram of the guided transport vehicle in Example 2;

[0034] Figure 5 This is a schematic diagram of torque analysis during torque balance via braking in Example 2;

[0035] Figure 6 This is a schematic diagram of torque analysis during the forward motion of the guided transport vehicle in Example 3, when torque balance is achieved.

[0036] Figure 7 This is a schematic diagram of the guided transport vehicle in Example 4;

[0037] Figure 8 This is a schematic diagram of torque analysis during the forward motion of the guided transport vehicle in Example 4, when torque balance is achieved.

[0038] Figure 9This is a schematic diagram of the guided transport vehicle in Example 5 turning and moving in the arc-shaped grooved guide rail;

[0039] Figure 10 This is a schematic diagram of torque analysis during the turning and moving process of the guide transport vehicle in Example 5, when the torque is balanced.

[0040] Figure 11 This is a schematic diagram of torque analysis during the lateral movement of the guide transport vehicle in Example 6, when torque balance is achieved.

[0041] Figure label:

[0042] 1-Car body; 21-Left front drive wheel; 22-Right front drive wheel; 23-Left rear drive wheel; 24-Right rear drive wheel; 25-Left front support wheel; 26-Left rear support wheel; 27-Right front support wheel; 28-Right rear support wheel; 31-Left front guide wheel; 32-Right front guide wheel; 33-Left rear guide wheel; 34-Right rear guide wheel; 35-Front guide wheel; 36-Rear guide wheel; 37-Auxiliary guide wheel; 4-Guide rail; 41-Groove guide rail; 42-Arc-shaped grooved guide rail. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Preferably, by designing and adjusting the counterweight, the center point O of the guided transport vehicle coincides with its center of mass. The guided transport vehicle has a symmetrical structure, with the traveling wheels and guide wheels installed in pairs and symmetrically. The angle of the component forces and the lever arm length of the traveling wheels and guide wheels in symmetrical positions are equal; this is beneficial for establishing a torque balance control model and achieving better control accuracy. In practical applications, the center of the guided transport vehicle does not coincide with its center of mass, the guided transport vehicle is not a symmetrical structure, and the traveling wheels and guide wheels are not installed in pairs or asymmetrically; the method proposed in this invention is still applicable. The guide component can be a roller, shaft, drum, wheel, column, or hemispherical structure, etc., used to cooperate and contact with the guide rail set on the ground during travel, and to be constrained by it, guiding the direction of the guided transport vehicle. The ground refers to a plane capable of supporting the operation of the guided transport vehicle; the plane height is not limited to the ground plane, but can be the floor of a platform, floor, or other structure.

[0044] Example 1

[0045] like Figure 1As shown, the guided transport vehicle includes a vehicle body 1, a set of wheels, and a guide assembly. The guided transport vehicle uses the guide assembly to guide its movement along the guide rail 4. In this embodiment, the set of wheels includes: a left front drive wheel 21, a right front drive wheel 22, a left rear drive wheel 23, and a right rear drive wheel 24. The guide assembly includes: a left front guide wheel 31, a right front guide wheel 32, a left rear guide wheel 33, and a right rear guide wheel 34. The left and right orientations refer to the guide assembly and the wheels being located on opposite sides of the longitudinal axis of the guided transport vehicle, respectively. The front and rear orientations refer to the guide assembly and the wheels being located on opposite sides of the transverse axis of the guided transport vehicle, respectively. The intersection of the longitudinal axis and the transverse axis is the center or centroid of the guided transport vehicle. The left and right orientations, as well as the front and rear orientations, are used to describe the positional relationship between the guide assembly / wheels and the center or centroid of the guided transport vehicle.

[0046] Force measuring devices are installed on each guide component of the guided transport vehicle to measure the force acting on the guide components. The traveling device of the guided transport vehicle includes components such as a motor, reducer, and traveling wheels. Torque sensors and speed sensors can be installed on the wheel axles, motor shafts, reducer shafts, etc. The detected signals can be converted to obtain the torque and speed of the traveling wheels. In this embodiment, torque sensors are installed on each drive wheel of the guided transport vehicle to detect the torque acting on each drive wheel, and speed sensors are installed to detect the speed of each drive wheel. The sensor signals are used to calculate the traction force of the drive wheels and also serve as feedback signals for the speed control device.

[0047] The force measuring device includes, but is not limited to: (1) a force measuring bearing on the bearing of the guide member in contact with the guide rail 4; (2) a force measuring sensor installed on the base or clamping device of the guide member; and (3) a displacement sensor installed on the elastic element of the clamping device to calculate the force based on the deformation. The force measured on the guide member is the reaction force of the guide rail on the guide wheel, and the force applied by the guide wheel to the guide rail is its action force. The perpendicular distance from the center point O of the vehicle body 1 to the component of the action force or the extension line of the action force is the lever arm. In the direction of travel, the sum of the rotational torques of the action forces of each guide wheel about the center point O of the vehicle body 1 forms the deflection torque of the transport vehicle's heading. The torques of each action force about the center point O of the vehicle body 1 are defined as follows: the torque that makes the vehicle body rotate counterclockwise is positive, and the torque that makes the vehicle body rotate clockwise is negative.

[0048] The relationship between motor torque, power, and speed:

[0049] M = 9550P / n

[0050] Where M is the electromagnetic torque of the motor; P is the power of the motor; and n is the speed of the motor (rpm).

[0051] When the traveling wheels are drive wheels driven by an electric motor drive unit,

[0052] M T=M

[0053] M T This is the traction torque of the traveling wheel.

[0054] M L =F L R

[0055] M L F is the static load torque of the drive wheel. L R represents the static load force, such as ground friction; R is the radius of the traveling wheel.

[0056] M B =F B R B

[0057] M B For the braking torque of the traveling wheels; F B Braking force for the walking wheels; R B Braking arm for the traveling wheels.

[0058]

[0059] GD 2 t is the flywheel torque of the traveling wheel; t is the time the force is applied.

[0060]

[0061] n' is the rotational speed of the traveling wheel (rpm); j is the speed ratio between the motor and the drive wheel, which can also be calculated from the rotational speed of the traveling wheel detected by the speed sensor on the drive wheel.

[0062] Ignoring factors such as mechanical efficiency and wear, the resultant force F of the traveling wheel is:

[0063]

[0064] When M T =M L When n = 0 or n = a constant value, the motor is stationary or rotating at a constant speed, the net force F = 0, the wheels rotate at a constant speed, and the transport vehicle travels at a constant speed. When the electromagnetic torque of the motor is increased, M T >M L When dn / dt > 0, the traveling wheel accelerates its rotation, and the net force F > 0. When the electromagnetic torque of the motor is reduced, M T <M L dn / dt<0, the walking wheel decelerates and rotates, and the resultant force F<0.

[0065] Alternatively, when the wheels rotate at a constant speed, the braking device applies a braking force F to the wheels. B This generates braking torque M B When M T -MB <M L dn / dt<0, the walking wheel decelerates and rotates, and the resultant force F<0.

[0066] like Figure 2 As shown, the driving motor of the traveling wheels generates a traction force on the traveling wheels through a transmission mechanism, which is entirely transferred to the ground. The reaction force of the ground on the traveling wheels is the traction force of the vehicle. By controlling the voltage, current, and frequency of the motor through a speed regulating device such as a speed controller or servo controller, i.e., controlling the output torque of the motor, the acceleration of the driving wheels can be controlled. This allows the traction force to be greater than or less than the static load force of the driving wheels. Alternatively, the voltage, current, and frequency of the motor can be controlled through a speed regulating device such as a speed controller or servo controller, i.e., controlling the output torque of the motor, thereby controlling the uniform rotation of the driving wheels. In addition, by controlling the braking device, a braking torque is applied to the traveling wheels. The resultant force of the braking force and the static load force is greater than the traction force, controlling the negative acceleration of the traveling wheels. The resultant force on the traveling wheels in the direction of travel drives the transport vehicle. The perpendicular distance from the center point O of the vehicle body 1 to its component force is the lever arm, forming the correction torque for the heading of the transport vehicle. Therefore, the force on the guide components is measured as the feedback quantity, and the output torque of each drive wheel is controlled by a speed regulating device such as a speed governor or servo controller as the control quantity. The control rule is to make the sum of the deflection torque and the correction torque zero or close to zero, achieving a balance in the vehicle's rotational torque; thus forming a closed-loop control. Ultimately, this ensures that the force on each guide component is nearly balanced, allowing the transport vehicle to travel smoothly and reducing mechanical wear and energy loss of the guide components and the traveling mechanism.

[0067] Specifically, for ease of explanation, the guided transport vehicle does not have support wheels and auxiliary guide components, but only has 4 drive wheels and 4 guide wheels, simplifying the yaw moment balance analysis of the transport vehicle as follows: Figure 3 As shown, F1 is the resultant force on the left front drive wheel 21; F2 is the resultant force on the right front drive wheel 22; F3 is the resultant force on the left rear drive wheel 23; F4 is the resultant force on the right rear drive wheel 24; θ is the angle between the resultant force and the component force; r1 is the drive wheel lever arm; r2 is the guide lever arm; f1' is the reaction force on the left front guide wheel 31; f2' is the reaction force on the right front guide wheel 32; f3' is the reaction force on the left rear guide wheel 33; f4' is the reaction force on the right rear guide wheel 34; α is the angle between the reaction force and the component force on the guide.

[0068] When the transport vehicle veers to the left, the left front guide wheel 31 first applies a force f1 to the left guide rail, and the right rear guide wheel 34 applies a force f4 to the right guide rail. Then, the left front guide wheel 31 experiences a reaction force f1' from the left guide rail, and the right rear guide wheel 34 experiences a reaction force f4' from the right guide rail. The magnitudes of the action and reaction forces are equal, their directions are opposite, and the angles between them and their respective components are equal (angle α). Without adjusting the traveling wheels, the corrective torque f2'cosαr2 + f3'cosαr2 - f1'cosαr2 - f4'cosαr2 returns the transport vehicle to the correct heading due to the guide rail reaction force. However, at this time, the left front guide wheel 31 and the right rear guide wheel 34 are under greater force. If the factors causing the veergence (uneven ground friction, uneven load, etc.) persist, the veergence will continue, leading to excessive wear on the left front guide wheel 31, the right rear guide wheel 34, and the traveling wheels on the corresponding sides.

[0069] Using the method of the present invention, such as Figure 3 As shown, by measuring the forces acting on the four guide components, the sum of the rotational torques about the center of the vehicle body generated by the increase in the forces acting on each guide wheel is used to determine whether deflection has occurred. Specifically, the force-measuring bearing of the left front guide wheel 31 detects an increase in the reaction force f1' from the left guide rail, directed to the right; the force-measuring bearing of the right rear guide wheel 34 detects an increase in the reaction force f4' from the right guide rail, directed to the left; the sum of the calculated rotational torques acting on the guided transport vehicle is a positive torque (counterclockwise deflection torque), and the guided transport vehicle deflects to the left. When the forces f2' on the right front guide wheel 32 and f3' on the left rear guide wheel 33 increase, the sum of the calculated rotational torques acting on the guided transport vehicle is a negative torque (clockwise deflection torque), and the guided transport vehicle deflects to the right.

[0070] The right front drive wheel 22 and the right rear drive wheel 24 maintain a constant speed, and the resultant forces F2 = 0 and F4 = 0. The electromagnetic torque of the motors for the left front drive wheel 21 and the left rear drive wheel 23 is increased by the speed regulating device, that is: making M... T >M L When dn / dt > 0, the motor accelerates, and the resultant forces F1 > 0 and F3 > 0 of the left front drive wheel 21 and left rear drive wheel 23. By controlling the voltage, current, and frequency of the respective motors of the left front drive wheel 21 and left rear drive wheel 23 using a speed control device such as a speed controller or servo controller, the output torque of the motors is controlled, thereby controlling the acceleration of each wheel and obtaining the resultant force of the left front drive wheel 21 and left rear drive wheel 23. This creates a negative torque (i.e., corrective torque) about the center point O of the vehicle body to counteract the positive torque (i.e., deflection torque) that causes the transport vehicle to deflect to the left. Based on torque balance:

[0071] f1cosαr2+f4cosαr2-f2cosαr2-f3cosαr2-F1cosθr1-F3cosθr1≈0; that is, by increasing the resultant force of the left front drive wheel 21 and the left rear drive wheel 23, the transport vehicle generates a negative torque to the right, thereby balancing the positive torque to the left of the transport vehicle, reducing the force on the left front guide wheel 31 and the right rear guide wheel 34, and thus maintaining the balance of the force on the four guide wheels of the transport vehicle.

[0072] Similarly, the electromagnetic torque of the motors for the right front drive wheel 22 and the right rear drive wheel 24 can also be reduced, i.e., by making M T <M L dn / dt<0, the motor decelerates, the resultant forces F2<0 and F4<0 of the right front drive wheel 22 and the right rear drive wheel 24 form a negative torque, i.e., a corrective torque, which can counteract the positive torque of the transport vehicle turning to the left, causing the transport vehicle to actively return to the correct position. f1cosαr2+f4cosαr2-f2cosαr2-f3cosαr2-F2cosθr1-F4cosθr1≈0, that is, by reducing the resultant force of the right front drive wheel 22 and the right rear drive wheel 24, the transport vehicle generates a negative torque to the right, thereby balancing the positive torque of the transport vehicle turning to the left.

[0073] In addition, braking force F can be applied through the braking device. B A braking torque M is generated on the drive wheel. B That is, satisfying M T -M B <M L Since dn / dt < 0, the resultant forces F2 < 0 and F4 < 0 of the right front drive wheel 22 and the right rear drive wheel 24 form a negative torque (i.e., a corrective torque) that can counteract the positive torque that causes the transport vehicle to deviate to the left, thus allowing the transport vehicle to actively return to its correct position. In this case, the traveling wheel drive device can also adopt the following structure: two traveling wheels located on both sides of the vehicle body are connected by a wheel axle, and the traveling wheel drive motor drives the wheel axle through a transmission mechanism to drive the two traveling wheels to rotate together and drive the guided transport vehicle to move.

[0074] Similarly, when the transport vehicle veers to the right, the negative torque of the veer to the right can be counteracted by increasing the speed of the right front drive wheel 22 and the right rear drive wheel 24 or decreasing the speed of the left front drive wheel 21 and the right front drive wheel 22 (by braking or motor deceleration) to generate a positive torque (i.e., a corrective torque), thereby causing the transport vehicle to actively return to the correct position.

[0075] Example 2

[0076] Based on Example 1, in this example, as... Figure 4As shown, the traveling wheels also include: a non-powered front left support wheel 25, a rear left support wheel 26, a front right right support wheel 27, and a rear right support wheel 28; each of the front left support wheel 25, rear left support wheel 26, front right support wheel 27, and rear right support wheel 28 is equipped with a braking device.

[0077] like Figure 5 As shown, when the transport vehicle turns to the left, while maintaining the uniform rotation of the four drive wheels (either by independently controlling the four drive wheels or by using the drive device structure in Embodiment 1 where one axle drives two drive wheels), when each support wheel rotates at a uniform speed, M T =M L By reducing the rotational speed of the right front support wheel 27 and the right rear support wheel 28, that is, by applying a braking torque M to the right front support wheel 27 and the right rear support wheel 28 respectively through the braking device. B Apply braking force F B The hydraulic system controls and adjusts the load based on the rotational speed (which can be calculated from the speed sensor on the support wheel) as feedback signal. Therefore, the resultant forces acting on the right front support wheel 27 and the right rear support wheel 28 are respectively... and F7 and F8 respectively generate negative torques (i.e., corrective torques) on the center point O of the vehicle body 1, which can counteract the positive torque that causes the transport vehicle to deviate to the left, thus causing the transport vehicle to actively return to the correct position. Alternatively, while increasing the rotational speed of the left front drive wheel 21 and the left rear drive wheel 23, the right front support wheel 27 and the right rear support wheel 28 can be braked to return the transport vehicle to the correct position.

[0078] Example 3

[0079] Based on embodiments 1 and 2, in this embodiment, the traction force of a traveling wheel can be adjusted by accelerating or decelerating it using a speed regulating device; alternatively, the traction force can be adjusted by applying braking torque to a traveling wheel using a braking device on the traveling wheel. Figure 6 As shown, one or more traveling wheels can be accelerated or decelerated simultaneously to adjust their traction; alternatively, one or more traveling wheels can be accelerated or decelerated while simultaneously applying braking torque to one or more traveling wheels for deceleration control, thus adjusting their traction. The sum of the torques of the resultant forces acting on each traveling wheel about the vehicle's center point O forms a corrective torque on the guided transport vehicle to balance the deflection torque, returning the transport vehicle to its correct position and maintaining a balanced force on the four guide wheels of the transport vehicle.

[0080] Example 4

[0081] In this embodiment, as Figure 7As shown, a guide assembly is provided on the longitudinal axis of the vehicle body 1, including a front guide wheel 35, a rear guide wheel 36 and an auxiliary guide wheel 37 in the middle. A grooved guide rail 41 is provided on the ground. The guide assembly is located in the grooved guide rail 41 and works together to guide the transport vehicle to travel along the grooved guide rail 41.

[0082] The number of guide components can be matched with the number of grooved guide rails, and there can be one or more sets. It can guide the transport vehicle to travel in multiple directions such as longitudinal and transverse. The torque balance control can be performed using the method of the present invention to make the transport vehicle travel smoothly.

[0083] Using the method of the present invention, such as Figure 8 As shown, the auxiliary guide wheel 37 in the middle is located at the center point O of the vehicle body 1, i.e., the rotating shaft does not generate rotational torque. By measuring the force on the two guide components, the sum of the rotational torques about the center of the vehicle body 1 generated by the increase of the force on each guide wheel is used to determine whether deflection has occurred. That is, if the force measuring device of the front guide wheel 35 detects an increase in the reaction force f1' on the left side of the grooved guide rail, it is applied to the left side of the front guide wheel 35 to the right; if the force measuring device of the rear guide wheel 36 detects an increase in the reaction force f4' on the right side of the grooved guide rail, it is applied to the right side of the front guide wheel 36 to the left; after calculation, the sum of the rotational torques on the guided transport vehicle is a positive torque (i.e., deflection torque), and the guided transport vehicle deflects to the left. If the force f2' on the front guide wheel 35 and the force f3' on the rear guide wheel 36 increase, after calculation, the sum of the rotational torques on the guided transport vehicle is a negative torque (i.e., deflection torque), and the guided transport vehicle deflects to the right.

[0084] By employing the correction torque control methods described in Examples 1, 2, and 3, the sum of the deflection torque and the correction torque is made zero or close to zero, achieving a balance in the vehicle's rotational torque. Ultimately, this ensures that the forces on each guide wheel are nearly balanced, enabling the transport vehicle to travel smoothly and reducing mechanical wear and energy loss in the guide components and traveling mechanism.

[0085] For example: Figure 8 As shown, when the guide car deflects to the left, the following torque balance control process is used to return the car to the center: f1r2+f4r2-F1cosθr1-F3cosθr1≈0, or f1r2+f4r2-F2cosθr1-F4cosθr1≈0.

[0086] Example 5

[0087] Based on Example 4, in this example, as Figure 9As shown, the guided transport vehicle uses front guide wheels 35 and rear guide wheels 36 within an arc-shaped grooved guide rail 42. The intermediate auxiliary guide wheel 37 is retractable and is driven by an electric push rod to retract into the vehicle body 1, disengaging from the arc-shaped grooved guide rail 42. The line connecting the axes of the front guide wheel 35 and the rear guide wheel 36 forms the chord of the central arc of the arc-shaped grooved guide rail 42. Driven by four steering wheels 21, 22, 23, and 24, the vehicle is guided by the arc-shaped grooved guide rail 42 to turn. The steering control of the four steering wheels during turning is prior art and will not be detailed in this embodiment. Figure 10 As shown, the transport vehicle turns at a constant speed along an arc with radius OP. Its centripetal force F0 is applied to the arc-shaped grooved guide rail 42 through the front guide wheel 35 and the rear guide wheel 36. The centripetal force F0 is decomposed into forces f1 and f3 acting on the arc-shaped grooved guide rail 42. The reaction force f1' of the front guide wheel 35 can be measured through its force measuring bearing, and the reaction force f3' of the rear guide wheel 36 can be measured through its force measuring bearing. During normal constant speed turning, f1' and f3' are of similar magnitude or fluctuate within the allowable range. The sum of the torques of the forces f1 and f3 about the center point O of the vehicle body is zero or close to zero.

[0088] When the measured reaction force f1' increases, f3' is zero, and the measured reaction force f4' is greater than zero, it can be concluded that the forces f1 and f4 increase. The lengths from the front guide wheel 35 and the rear guide wheel 36 to the center point O of the vehicle body 1, OE and OF, are r2. Based on OE and the radius PE of the center circle of the arc-shaped groove guide rail 42, the angle θ5 and the lever arm L of OE and the force f1 can be calculated. OG The included angle is equal to θ5, and the torque of force f1 about the center O of vehicle body 1 is f1r2cosθ5; the front guide wheel 35 and the rear guide wheel 36 are symmetrically installed, so the torque of force f4 about the center O of vehicle body 1 is f4r2cosθ5; based on the sum of the torques of forces f1 and f4, f1r2cosθ5 + f4r2cosθ5, it is determined that the transport vehicle deflects to the left, and the deflection torque is a positive torque. The steering angles of the corresponding drive wheels 21, 22, 23, and 24 are angles α1, α2, α3, and α4, respectively; the drive wheels are symmetrically installed, and the lengths of the lines OA, OB, OC, and OD connecting each drive wheel to the center O of the vehicle body are all r1, and the angle between the connecting lines and the positive direction of the traveling wheels (the straight-line travel state of the transport vehicle) is angle β. Figure 10 As shown, according to torque balance control, the left rear drive wheel 23 and right rear drive wheel 24 maintain uniform rotation, while the left front drive wheel 21 and right front drive wheel 22 are controlled to decelerate, generating a negative torque to correct the deviation. The calculated angles between the lever arms of the two drive wheels are θ1=α1-β and θ2=α2+β, respectively. The lever arm of the force of the two drive wheels about the center O of the vehicle body is the axis of rotation, i.e., the perpendicular distance from the center O of the vehicle body to the line of action of the force of the drive wheel, i.e., L. OG =r1sinθ1,LOH =r1sinθ2. The torque balance control process for returning the transport vehicle to its center position is: f1r2cosθ5 + f4r2cosθ5 - f3r2cosθ5 - F1r1sinθ1 - F2r1sinθ2 ≈ 0. Ultimately, F1 = 0, F2 = 0, the left front drive wheel 21 and right front drive wheel 22 rotate at a constant speed, f1r2cosθ5 - f3r2cosθ5 ≈ 0, and the transport vehicle resumes low-resistance, uniform turning motion along the arc-shaped grooved guide rail 42. f1' and f3' are roughly equal in magnitude or fluctuate within the allowable range. The sum of the torques of forces f1 and f3 about the vehicle's center point O is zero or close to zero. The method for controlling the traveling wheels to generate corrective torque in Examples 1, 2, and 3 is applicable to this example.

[0089] Similarly, with left and right guide wheels installed on the vehicle body and matched with suitable arc-shaped grooved guide rails 42, the guided transport vehicle in this embodiment can turn and move laterally according to the above control process.

[0090] Example 6

[0091] If data such as the magnitude and direction of the radial force on the shaft of the guide member are obtained through a measuring device, such as a force-measuring bearing, and the torque of the force and its lever arm about the center or center of mass of the guide transporter is calculated more accurately using such detailed force data, compared with the method of calculating the torque by pre-determining the direction of the force and its lever arm based on the position of the guide member and its geometric relationship with other parts such as the vehicle body and guide rails, then the sum of the torques of all guide members about the center or center of mass of the guide transporter obtained in this way, i.e., the deflection torque, is more accurate, which is beneficial to improving the control accuracy and applicability of the torque balance control method of the present invention. For example, as follows... Figure 7 As shown, the guided transport vehicle is driven by transverse drive wheel sets located at both ends to move along two transversely arranged grooved guide rails 41. The shafts of the front guide wheel 35 and the rear guide wheel 36 are both fitted with force-measuring bearings. The two guide wheels are respectively positioned in the two grooved guide rails 41 to guide the guided transport vehicle to move laterally. The auxiliary guide wheel 37 is mounted on a base driven by an electric push rod and retracts into the vehicle body, disengaging from the longitudinally arranged grooved guide rails 41. If we consider the positions of the front guide wheel 35 and the rear guide wheel 36 and their geometric relationship with the vehicle body, guide rails, and other parts, the direction of the force is on the longitudinal axis described in Embodiment 1, and its extension line passes through the center or center of mass of the guided transport vehicle. The lever arm length of the force is zero, so it is impossible to calculate the sum of the torques of the front guide wheel 35 and the rear guide wheel 36 about the center or center of mass of the guided transport vehicle. There is no deflection torque, and it seems that the torque balance control method described in this invention cannot be applied. However, in reality, there is a gap in the fit between the guide wheel and the guide rail. When the guided transport vehicle deflects laterally, such as Figure 11As shown, the forces f5 and f6 exerted by the front guide wheel 35 and the rear guide wheel 36 on the grooved guide rail 41 are not on the longitudinal axis of the vehicle body, but at certain angles θ6 and θ7 with the longitudinal axis. The magnitude and direction of the radial forces f5' and f6' on the shafts of the front guide wheel 35 and the rear guide wheel 36 are obtained through the force measuring bearing, and the forces f5 and f6 and their lever arms L are calculated based on this. OK and L OL The sum of the torques at the center or center of mass of the guide transporter can be used to obtain the clockwise deflection positive torque. Based on the torque balance, the correction torque control method of Examples 1, 2, and 3 is adopted, F5r1sinα+F6r1sinα-f5r2sinθ6-f6r2sinθ7≈0, so that the sum of the deflection positive torque and the correction negative torque is zero or close to zero, thus achieving the balance of vehicle body rotation torque.

[0092] In summary, the guided transport vehicle with side or bottom guidance and wheels that travel directly on the ground can use this invention to control its heading in various driving states such as straight, sideways, translation, turning, and spinning.

[0093] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A torque balance control method for a guided transport vehicle, wherein the guided transport vehicle moves along a guide rail, a guide member on the vehicle contacts the guide rail, the guided transport vehicle deflects, and the force exerted by the guide member on the guide rail causes the guide member to experience a reaction force from the guide rail, characterized in that, Force measuring devices are installed on each guide component of the guided transport vehicle to measure the force on the guide component; A speed sensor and / or torque sensor are installed on each traveling device of the guided transport vehicle. The speed sensor is used to detect the speed of each traveling wheel, and the torque sensor is used to detect the torque on each traveling wheel. The sum of the torques of the forces exerted by each guide component on the guide rail on the center or center of mass of the guided transport vehicle forms the deflection torque of the guided transport vehicle's heading; the sum of the torques of the forces exerted by each traveling wheel on the vehicle body on the center or center of mass of the guided transport vehicle forms the correction torque of the guided transport vehicle's heading. The method includes: Step S1: Obtain the force data of the guide component measured by the force measuring device under the current state of the guided transport vehicle. When the force on the guide component increases abnormally, determine and calculate the deflection torque of the guided transport vehicle. Step S2: Based on the principle of torque balance, the output torque or braking torque of each traveling wheel is controlled according to the deflection torque of the guide vehicle, thereby controlling the correction torque of each traveling wheel on the vehicle body, so that the deflection torque and the correction torque reach torque balance, the guide vehicle resumes the predetermined course and travels stably, and the force data of each guide component measured by the force measuring device are balanced or meet expectations.

2. The method as described in claim 1, characterized in that, The traveling wheels include: drive wheels and support wheels; The guide components include: a left front guide component, a right front guide component, a left rear guide component, and a right rear guide component; Step S1 includes: when the guided transport vehicle is traveling longitudinally, if the force measuring device detects that the reaction force on at least one of the guide members in the left or / and right directions increases, based on the direction of the sum of the moments of the forces of each guide member about the center of the vehicle body or the center of mass, it is determined that the guided transport vehicle has deflected to the side of the expected course, and the deflection moment is calculated; or When the guided transport vehicle is traveling laterally, the force measuring device detects that the reaction force on at least one of the guide members in the front or / and rear positions increases. Based on the direction of the sum of the moments of the forces of each guide member about the center of the vehicle body or the center of mass, it is determined that the guided transport vehicle has deflected to the side of the expected course, and the deflection moment is calculated.

3. The method as described in claim 1, characterized in that, The traveling wheels include: drive wheels and support wheels; The guide components include: a front guide component and a rear guide component arranged along or parallel to the longitudinal axis of the guided transport vehicle; and a left guide component and a right guide component arranged along or parallel to the transverse axis of the guided transport vehicle. Step S1 includes: when the guided transport vehicle is traveling longitudinally, if the force measuring device detects that the reaction force on at least one of the front or / and rear guide members increases, based on the direction of the sum of the moments of the forces of each guide member about the center of the vehicle body or the center of mass, it is determined that the guided transport vehicle has deflected to one side of the expected course, and the deflection moment is calculated; or When the guided transport vehicle is traveling laterally, the force measuring device detects that the reaction force on at least one of the left or / and right guide members increases. Based on the direction of the sum of the moments of the forces of each guide member about the center of the vehicle body or the center of mass, it determines that the guided transport vehicle has deflected to the side of the expected course and calculates the deflection moment.

4. The method as described in claim 2 or 3, characterized in that, Step S2 includes: Based on the torque balance, the correction torque is derived from the deflection torque. The correction torque is decomposed into the torque controlling the drive wheel about the center or center of mass of the guide vehicle, increasing the output torque of the drive wheel on the deflection side, increasing its speed, and thus increasing the force of the drive wheel on the vehicle body. Alternatively, reduce the output torque of the drive wheel on the opposite side of the deflection, reduce its speed, and thus increase the force exerted by the drive wheel on the opposite side of the deflection on the vehicle body in the opposite direction of travel. Alternatively, increase the force exerted by the drive wheel on the deflection side on the vehicle body and increase the force exerted by the drive wheel on the opposite deflection side on the vehicle body in the opposite direction; The sum of the torques exerted by each controlled drive wheel on the vehicle body on the center or center of mass of the guided transport vehicle forms the corrective torque.

5. The method as described in claim 2 or 3, characterized in that, The drive wheel and / or support wheel are equipped with a braking device; When the guided transport vehicle deflects to one side, a corrective torque is derived from the deflection torque based on torque balance. This corrective torque is decomposed into the torques of the drive wheels and / or support wheels about the center or center of gravity of the guided transport vehicle. A braking torque is applied to the drive wheels and / or support wheels on the opposite side of the deflection through a braking device, reducing their rotational speed and thus increasing the force exerted by the drive wheels on the opposite side of the deflection on the vehicle body in the opposite direction of travel. The sum of the torques of the forces exerted by each braked drive wheel and / or support wheel on the vehicle body in the opposite direction of travel about the center or center of gravity of the guided transport vehicle forms the corrective torque.

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