CN109050244B

CN109050244B - High-precision AGV driving and steering integrated device and control method thereof

Info

Publication number: CN109050244B
Application number: CN201811025077.9A
Authority: CN
Inventors: 邢科新; 林叶贵
Original assignee: Zhejiang Tongzhu Technology Co ltd
Current assignee: Zhejiang Tongzhu Technology Co ltd
Priority date: 2018-09-04
Filing date: 2018-09-04
Publication date: 2021-07-16
Anticipated expiration: 2038-09-04
Also published as: CN109050244A

Abstract

The utility model provides a AGV drive of high accuracy turns to integrated device, includes drive module and independent steering module, drive module includes drive wheel, walking motor and resolver, integrated device still includes transmission module, transmission module includes supporting seat and second grade reduction gears, the independent steering module of installation on the bearing. The steering speed reducer and the steering motor are vertically and parallelly installed, so that the height between the independent steering module and the ground is greatly reduced, and the requirement of the AGV on the road flatness is reduced; and provides a high-precision AGV driving and steering integrated control method. The invention provides a high-precision AGV driving and steering integrated device which is good in flexibility, simple in structure, good in stability and easy to control, and a control method thereof.

Description

High-precision AGV driving and steering integrated device and control method thereof

Technical Field

The invention belongs to the field of automatic transportation equipment, and particularly relates to a high-precision AGV driving and steering integrated device and a control method thereof, which are used for realizing the steering and speed control of an AGV.

Background

Automated Guided Vehicles (AGVs) have an autonomous driving function in unstructured environments, which have become key devices of Automated logistics transportation systems and flexible manufacturing systems. Therefore, the AGV has a explosive growth in domestic demands in industries such as electronic product assembly, automobile manufacturing and logistics, and has a wide development prospect.

The driving and steering integrated device is a core component of an AGV (automatic guided vehicle) system, and the traditional AGV driving system comprises a single-wheel driving mode and a differential driving mode. The AGV with the single-wheel driving mode has the advantages that one single-wheel driving unit comprises a steering part, two driven wheels are generally fixed wheels which cannot be steered, and the turning radius of the structure is large. The differential drive type AGV carries out steering control through the speed difference of two symmetrical driving motors on the left and the right, is relatively complicated to control, is easy to have speed deviation under the high-speed condition, and is out of control. Therefore, the differential-drive AGV cannot meet the transportation scenario with high degree of freedom and large load.

At present, an all-directional driving system is also available in the industry market, and the all-directional driving system has the characteristics of large load capacity and high degree of freedom. In chinese patent, some omnibearing driving devices and methods are disclosed. For example, in the steering wheel driving device of the publication No. CN103895695A, the height of the steering motor from the ground is small, and the steering motor may rub against the ground and even damage the motor in a complex road environment with poor flatness. If a high power steering motor is used or a speed reducer with a larger reduction ratio is used, the height of the steering motor from the ground is smaller. In addition, the device drives the bull gear to rotate through the rotation of the pinion of the steering motor, and the bull gear drives the driving wheel axle through the steering support, so that the driving wheel assembly is steered. A drive device designed in this way. There is a risk that the drive motor collides with the steering motor during steering. For example, in the "multi-wheel-train mobile robot steering synchronization system" with the publication number CN202542387U, a rotary encoder is mounted on the driving support, and the end of the rotating shaft of the rotary encoder is connected to a corner pinion engaged with the fixed gearwheel. Because the encoder detects the speed of the steering motor after being decelerated, on one hand, the error of a feedback signal of the rotary encoder is increased by a mode of mounting an angle feedback sensor through gear transmission, the stability of the AGV in the running process is influenced, and the attachment wanders in a set position in severe cases; on the other hand, the effective encoder resolution for controlling the motor may be reduced. The steering motor of the driving device has the same height from the ground, and the steering motor can rub against the ground and even damage the motor under the condition of a concave-convex road surface. In addition, the design uses a three-phase alternating current induction motor, a complex driver is needed, and meanwhile, the starting torque under the heavy load condition and the high-precision traveling track condition cannot be met.

Disclosure of Invention

In order to overcome the defects of poor flexibility, complex structure and difficulty in control of the conventional AGV driving device, the invention provides the high-precision AGV driving and steering integrated device which is good in flexibility, simple in structure, good in stability and easy to control and the control method thereof.

In order to solve the technical problems, the invention provides the following technical scheme:

the high-precision AGV driving and steering integrated device comprises a driving module and an independent steering module, wherein the driving module comprises a driving wheel, a walking motor and a rotary transformer, the integrated device further comprises a transmission module, the transmission module comprises a supporting seat and a secondary speed reducing mechanism, the secondary speed reducing mechanism comprises a transmission gear wheel and a gear shaft, the gear shaft can be installed in the supporting seat, the transmission gear wheel is fixedly installed on the gear shaft, the gear shaft is provided with external teeth, and the external teeth are meshed with the inner gear ring of the driving wheel; and a transmission pinion is arranged on an output shaft of the walking motor and meshed with the transmission gearwheel, and an independent steering module is arranged on the supporting seat.

Further, the independent steering module comprises a supporting plate, a rotary supporting bearing, a steering motor, a speed reducer and a steering gear; the backup pad is fixed on the supporting seat, slewing bearing includes inner circle and outer lane, inner circle and backup pad fixed connection, and the outer lane is equipped with the gear fixed with the AGV frame, turn to motor bearing handstand state, output shaft and speed reducer input shaft parallel placement are connected through sprocket and belt between motor output shaft and the speed reducer input shaft, the speed reducer is fixed in the backup pad below, and the output shaft of speed reducer passes backup pad and steering gear coaxial arrangement, steering gear and slewing bearing outer lane gear engagement.

Still further, the walking motor adopts brushless servo motor, adopts rotary transformer as walking motor's speed feedback sensor.

Furthermore, the steering motor is a direct-current brushless servo motor, and the steering motor and the speed reducer are vertically arranged in parallel and are driven by a chain wheel and a belt.

And an absolute value encoder is arranged on a shaft of the steering motor.

Two independent limit switches are placed on the supporting seat.

The walking motor is integrated into the driving wheel, and the rotary transformer is integrated on a rear shaft of the walking motor; a first supporting bearing and a second supporting bearing are installed in the supporting seat, and the gear shaft is installed on the first supporting bearing and the second supporting bearing.

The driving module further comprises an electromagnetic brake, and the electromagnetic brake is installed at the front end of the output shaft of the walking motor.

The inner ring is fixed on a support plate, two independent limit switches are fixedly installed on the support plate, and a magnetic navigation sensor is installed below the support plate, which is an optimal scheme; the control mode of the invention is not limited to the magnetic navigation mode, and other modes such as laser navigation and visual navigation are also applicable to the invention.

A high-precision AGV driving and steering integrated control method comprises the following steps:

step 1: powering on the system and opening the electromagnetic brake;

step 2: the servo driver controls a traveling brushless servo motor, and the motor drives a two-stage speed reducing mechanism in the speed reducing box body so as to drive the driving wheel to move; the rotary transformer directly connected with the rear shaft of the walking motor feeds back the speed information of the motor to the driver, and the driver controls the servo driver to control the speed of the motor through the speed feedback of a closed loop so as to enable the driving wheel to move back and forth;

step 3: the steering module directly reads the current position information through an absolute position encoder to judge the angle position of the current steering module;

and 4, step 4: the navigation sensor detects the position information of the current path at any moment, and the controller performs an active disturbance rejection motion control algorithm according to the deviation condition of the current path information and the target position information to obtain the output quantity of the steering motor;

and 5: the steering motor is used for position control of a closed loop through the driver, the motor drives the chain wheel, the chain wheel drives the speed reducer, the speed reducer drives the outer ring of the slewing support bearing to move through meshing of the steering gear and the outer ring gear of the slewing support bearing, and finally steering of the driving wheel is achieved. The absolute value encoder can read the current steering angle information in real time;

step 6: when the steering amplitude is larger than the range limited by the two safety limit switches, the limit switches are triggered to output limit signals, and the steering motor stops steering;

and 7: when the walking stops, the electromagnetic brake is braked, so that the phenomenon that the walking motor moves and slips down a slope is prevented.

The technical conception of the invention is as follows: the traveling motor provides power for the transmission module, the output end of the transmission module is connected with the driving wheel, and the output torque is increased by utilizing the secondary speed reducing structure in the supporting seat cavity to drive the AGV to move; the speed feedback semaphore is transmitted to a controller to realize the speed control of the AGV; a rotary transformer directly connected with a walking motor is used as a feedback sensor, so that the shock resistance is effectively realized, and the stability is better; the AGV steering mechanism has the advantages that the all-directional movement of the AGV is realized through the independent steering module, and the steering motor is perpendicular to and parallel to the speed reducer, so that the height of the whole independent steering module is greatly reduced; meanwhile, the steering motor and the speed reducer are driven by a chain wheel, so that primary speed reduction is added, and the driving capability of the steering module is increased; the absolute value encoder directly connected with the steering motor is used for feeding back, so that the precision of a steering angle feedback signal is increased, the backlash error caused by gear transmission is reduced, and the phenomenon that equipment swings back and forth near a set position due to an angle control error is prevented; the absolute value encoder can also retain position information when the power is off, so that the AGV system can be ensured to be electrified and the position angle of the current driving wheel can be directly read, a user can directly know the current angle position of the driving wheel, and the direction can be conveniently controlled by the user; two limit switches are adopted to limit the steering angle, and the safety of the system is improved. The improved omnibearing driving mode has the advantages of compact structure, simple walking and steering control, high flexibility and strong driving force, and can realize high-freedom-degree motion under the condition of AGV heavy load. The speed and angle feedback unit is directly connected with the walking motor and the steering motor, the feedback signal is accurate, and the backlash error caused by gear transmission is reduced. The reduction of the height of the independent steering module enables the AGV to operate under more complex working conditions.

The invention has the following beneficial effects: 1. the steering speed reducer and the steering motor are vertically and parallelly installed, so that the height between the independent steering module and the ground is greatly reduced, the requirement of the AGV on the road flatness is reduced, and the driving wheel is suitable for more complex ground environments; meanwhile, the motor and the speed reducer are driven by the chain wheel and the belt, so that the first-stage speed reduction is added, and the driving capability of the steering module is increased.

2. The absolute value encoder feedback module of the independent steering module is directly connected with the steering motor, so that the feedback accuracy is improved, and the backlash error caused by gear transmission is reduced. And simultaneously, the phenomenon that the equipment wanders back and forth near the set position due to the angle control error is prevented. The equipment has good motion stability and is suitable for different working conditions.

3. The absolute value encoder can also retain the current position information when the power is off, so that the AGV system can be ensured to be electrified and the position angle of the current driving wheel can be directly read, a user can directly read the current angle position of the driving wheel, and the direction can be conveniently controlled by the user;

4. the supporting seat is ingenious in design and plays a supporting role, two independent limit switches are placed on the supporting seat, the steering angle can be effectively limited, and the system safety performance is higher.

5. The walking driving motor adopts a brushless servo motor, does not need additional maintenance, and reduces the cost of later maintenance. Meanwhile, the rotary transformer is used as a speed feedback sensor of the walking motor, so that the shock resistance can be effectively realized, the system stability is improved, and the system is more suitable for scenes with poor ground environment.

Drawings

FIG. 1 is a schematic front view of a high accuracy AGV drive steering integrated apparatus.

FIG. 2 is a schematic side view of a high accuracy AGV drive steering integrated apparatus.

FIG. 3 is a schematic diagram of the internal cross-sectional structure of a high-precision AGV driving and steering integrated device

In the figure, 1 a driving wheel 2 walking motor 3 a resolver 4, an electromagnetic brake 5, a transmission pinion 6, a rotary support bearing 61, a rotary support bearing outer ring gear 62, a rotary support bearing inner ring 7, a transmission bull gear 10, a support bearing 8, a support bearing 111, a support bearing 212, a gear shaft 13, a support plate 14, a speed reducer 15, a steering motor 16, a steering gear 17 and an absolute value encoder 18 limit switch.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1-3, a high-precision AGV driving and steering integrated device comprises a driving module and an independent steering module, wherein the driving module comprises a driving wheel 1, a walking motor 2 and a rotary transformer 3, the integrated device further comprises a transmission module, the transmission module comprises a supporting seat 7 and a secondary speed reducing mechanism, the secondary speed reducing mechanism comprises a transmission big gear 9 and a gear shaft 12, the gear shaft 12 is rotatably installed in the supporting seat 7, the gear shaft 12 is provided with external teeth, and the external teeth are meshed with an inner gear ring 8 of the driving wheel 1; the output shaft of the walking motor 2 is provided with a transmission pinion 5, the transmission pinion 5 is meshed with the transmission gearwheel 9, and the supporting seat 7 is provided with the independent steering module.

Further, the independent steering module comprises a support plate 13, a speed reducer 14, a steering motor 15 and a steering gear 16; the supporting plate 13 is fixed on the supporting seat 7 and used for connecting the transmission module and the independent steering module; the inner ring of the rotary support bearing is fixedly connected with the support plate 13, so that the driving module, the transmission module and the independent steering module are mutually fixed into a whole; the outer ring is provided with a gear 61, the outer ring gear 61 is provided with a screw hole, and the screw hole is fixedly connected with an AGV frame which is not shown; the steering motor 15 is arranged below the supporting plate, so that the steering motor and the speed reducer are vertically arranged in parallel; the speed reducer 14 is fixed below the support plate 13, and an output shaft of the speed reducer 14 passes through the support plate 13 and is coaxially mounted with the steering gear 16; the steering gear 16 intermeshes with the slewing support bearing outer ring gear 61. When the controller controls the AGV to steer, because the rotary supporting bearing outer ring gear 61 is fixed with the AGV frame, after the steering motor 15 decelerates through the belt chain wheel and the speed reducer 14 to increase the moment, the steering gear 16 moves around the rotary supporting bearing outer ring gear 61, so that the supporting plate 13 of the independent steering mechanism, the rotary supporting bearing inner ring 62, the steering motor 15, the speed reducer 14 and the supporting seat 7, the driving wheel 2 and the walking motor 2 rotate around the rotary supporting bearing outer ring gear 61 along with the speed reducer, the AGV steering is realized, and the relative positions of the walking motor 2 and the steering motor 15 are always fixed.

Still further, the traveling motor 2 adopts a brushless servo motor, and the rotary transformer 3 is adopted as a speed feedback sensor of the traveling motor.

Furthermore, the steering motor 15 is a dc brushless servo motor, and the steering motor 15 and the speed reducer 14 are vertically arranged in parallel and driven by a sprocket and a belt.

The independent steering module encoder feedback module is directly connected to the drive motor and the steering motor 15.

An absolute value encoder 17 is mounted on the shaft of the steering motor 15.

Two independent limit switches 18 are arranged on the supporting seat 7.

The walking motor 2 is integrated into the driving wheel 1; the rotary transformer 3 is directly connected with the walking motor 2; first support bearing 10 and second support bearing 11 of installation in the supporting seat 7, pinion 12 suit is in on first support bearing 10 and the second support bearing 11.

In the driving module, the walking motor 2 is integrated into the driving wheel 1, and the output shaft of the walking motor is provided with a transmission pinion 5; the walking motor 2 is a direct-current brushless servo motor; the electromagnetic brake 4 is coaxially arranged at the front end of the walking motor 2 and is fixed on the supporting seat 7 through screws. When the system is powered on, the brake spring plate is popped up through the electromagnetic induction principle; when the AGV parks, the system is powered off, and the spring plate is closed to play a role in braking.

The transmission module comprises a supporting seat 7 for supporting. A secondary speed reducing structure is arranged in the cavity of the supporting seat 7 and comprises a transmission large gear 9, a first supporting bearing 10, a second supporting bearing 11 and a gear shaft 12; the transmission gearwheel 9, the first support bearing 10 and the second support bearing 11 are sleeved on the gear shaft 12; the transmission power is provided by the walking motor 2, the transmission pinion 5 on the output shaft of the walking motor is meshed with the transmission big gear 9, the gear shaft 12 is meshed with the driving wheel inner gear ring 8, so that the transmission pinion 5 drives the transmission big gear 9, the transmission big gear 9 drives the gear shaft 12, the gear shaft 12 drives the driving wheel inner gear ring 8, the inner wall and the outer wall of the thin-wall bearing on the driving wheel 2 move relatively, and the driving wheel 2 is driven to move. The first support bearing 10 and the second support bearing 11 play a supporting role.

The absolute value encoder 17 feedback module is directly connected with the steering motor 15, after the controller sets the angle to be rotated, the feedback encoder 17 records the steering position and feeds the steering position back to the controller, and when the fed-back angle signal is consistent with the preset rotation angle, the steering is stopped.

The controller controls the walking motor 2 and the steering motor 15 to realize synchronous all-directional actions of the device such as forward moving, backward moving, pivot steering, transverse moving, oblique moving and the like.

Two limit switches 18 of the sensor unit are fixed to the support plate 13, and a switch signal is transmitted to the controller to limit the range of the steering angle.

The sensor unit further includes a magnetic navigation sensor (not shown in the drawings), which is fixed to the support plate through a bracket, outputs a navigation position signal, and transmits the navigation position signal to the controller. The above examples merely represent one embodiment of the present invention and are not to be construed as limiting the scope of the invention. It should be noted that a person skilled in the art could make several alternative designs without departing from the inventive concept, which falls within the scope of the invention.

step 1: powering on the system and opening the electromagnetic brake;

Claims

1. The utility model provides a AGV drive of high accuracy turns to integrated device, includes drive module and independently turns to the module, drive module is including walking motor, drive wheel and resolver, its characterized in that: the integrated device further comprises a transmission module, the transmission module comprises a supporting seat and a secondary speed reducing mechanism, the secondary speed reducing mechanism comprises a transmission large gear and a gear shaft, the gear shaft is rotatably installed in the supporting seat, the transmission large gear is fixedly installed on the gear shaft, the gear shaft is provided with external teeth, and the external teeth are meshed with an inner gear ring of the driving wheel; a transmission pinion is mounted on an output shaft of the walking motor and meshed with the transmission gearwheel, and the independent steering module is mounted on the supporting seat; the independent steering module comprises a supporting plate, a rotary supporting bearing, a steering motor, a speed reducer and a steering gear; the AGV turning device comprises a supporting seat, a turning supporting bearing, a turning motor, a speed reducer input shaft, a turning motor, a steering motor, a belt and an absolute value encoder, wherein the supporting seat is fixed on the supporting seat, the turning supporting bearing comprises an inner ring and an outer ring, the inner ring is fixed on the supporting seat, the outer ring is provided with a gear fixed with the AGV frame, the turning motor is a direct-current brushless servo motor and is in an inverted state, the output shaft of the turning motor is vertically and parallelly arranged with the input shaft of the speed reducer, the output shaft; the speed reducer is fixed below the supporting plate, an output shaft of the speed reducer penetrates through the supporting plate and is coaxially mounted with the steering gear, and the steering gear is meshed with the outer ring gear of the rotary supporting bearing; the walking motor adopts a brushless servo motor, and a rotary transformer is adopted as a speed feedback sensor of the walking motor;

when controlling the AGV to turn to, because slewing bearing outer ring gear and AGV frame are fixed, turn to the motor and through the speed reducer speed reduction increase moment, make steering gear around slewing bearing outer ring gear motion, and then make the backup pad that independently turns to the module, slewing bearing inner circle, turn to the motor, speed reducer and supporting seat, drive wheel, walking motor and rotate around slewing bearing outer ring gear together, realize that the AGV turns to, and the relative position of walking motor and turning to the motor is fixed unchangeable all the time.

2. An integrated AGV drive and steering arrangement of high accuracy as claimed in claim 1 wherein: two independent limit switches are placed on the supporting seat.

3. An integrated AGV drive and steering arrangement of high accuracy as claimed in claim 1 wherein: the walking motor is integrated into the driving wheel, the rotary transformer is integrated on a rear shaft of the walking motor, a first supporting bearing and a second supporting bearing are installed in the supporting seat, and the gear shaft is installed on the first supporting bearing and the second supporting bearing.

4. An integrated AGV drive and steering arrangement of high accuracy as claimed in claim 1 wherein: the driving module further comprises an electromagnetic brake, and the electromagnetic brake is installed at the front end of the output shaft of the walking motor.

5. An integrated AGV drive and steering arrangement of high accuracy as claimed in claim 1 wherein: two independent limit switches are fixedly installed on the supporting plate, and a magnetic navigation sensor is installed below the supporting plate.

6. A control method of an AGV drive steering integration control device with high precision according to any one of claims 1 to 5, wherein the control method comprises the following steps:

step 1: powering on the system and opening the electromagnetic brake;

and step 3: the steering module directly reads the current position information through an absolute position encoder to judge the angle position of the current steering module;

and 5: the steering motor is used for carrying out closed-loop position control through a driver, the motor drives a chain wheel, the chain wheel drives a speed reducer, the speed reducer drives the outer ring of the slewing support bearing to move through the meshing of a steering gear and a slewing support bearing outer ring gear, and finally the steering of the driving wheel is realized; the absolute value encoder can read the current steering angle information in real time;