CN113199454A

Movatterモバイル変換

Info

Publication number: CN113199454A
Application number: CN202110694240.6A
Authority: CN
Inventors: 李立军; 张红军
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2021-06-22
Filing date: 2021-06-22
Publication date: 2021-08-03

Abstract

The storage, letter sorting, the transportation task of commodity circulation trade are more and more heavy, and time rhythm is more and more fast, and traditional manual work or semi-automatization operation mode, inefficiency, easy mistake, human cost are high, need to develop the intelligent logistics robot that the translation rate is fast, the carrying capacity is strong, the motion is nimble urgently. The invention provides a wheel type mobile intelligent logistics operation robot system, which belongs to the technical field of mechanical electronic automation and comprises wheels, a coding motor, a vehicle body, a control system module, an inertia measurement module, a lithium battery, a single chip microcomputer, an object stage, a sensor support, a depth camera, a wide-angle monocular camera, a laser radar, a mechanical arm, a supporting leg and an ultrasonic sensor.

Description

Wheeled mobile intelligent logistics operation robot system

Technical Field

The invention relates to a robot system, in particular to a wheeled mobile intelligent logistics operation robot system, and belongs to the technical field of mechanical and electronic automation.

Background

In recent years, the logistics industry is rapidly developed, the tasks of warehousing, sorting and transporting goods are more and more heavy, and the time rhythm is faster and faster. The traditional manual or semi-automatic operation mode has low efficiency, high labor cost and high error probability, and can not meet the development requirements of the logistics transportation industry. The robot that wheeled removed has the translation rate fast, and carrying capacity is strong, and the motion is nimble, accomplishes snatching, letter sorting, the transportation operation of goods moreover easily, consequently becomes the key direction of intelligent manufacturing equipment development in the commodity circulation trade. The wheeled operation robot with the functions of positioning, navigation, target recognition and object grabbing can meet the requirements of the logistics industry on quick, safe and low-cost intelligent carrying equipment, and has a very wide application prospect.

Disclosure of Invention

1. The purpose of the invention is as follows:

the invention provides a robot system which can move rapidly and autonomously, can automatically identify goods, position, grab and unload the goods to a designated area, and can work in closed road environments such as warehouses, factories and the like.

2. The technical scheme is as follows:

the invention discloses a wheeled mobile intelligent logistics operation robot system which is characterized by comprising the following parts: the system comprises wheels, a coding motor, a vehicle body, a control system module, an inertia measurement module, a lithium battery, a single chip microcomputer, an objective table, a sensor support, a depth camera, a wide-angle monocular camera, a laser radar, a mechanical arm, a supporting leg and an ultrasonic sensor; the relationship between them is: the wheel bearing vehicle body is connected with a coding motor which drives the wheels to roll and outputs corresponding coding information, the processed coding information is used as a odometer for the movement of the vehicle body, and the vehicle body is used as a bearing body of each component; the control system module is used as a controller module of the whole system and is responsible for processing data collected by the depth camera, the wide-angle monocular camera and the laser radar and sending corresponding instructions to the single chip microcomputer after processing; the inertia measurement module is positioned at the mass center of the vehicle body and used as a judgment device of the motion attitude of the robot, and simultaneously assists in correcting the information of the odometer; the lithium battery is used as a power supply module of the whole system and provides electric power support for the whole system, the single chip microcomputer is responsible for receiving information transmitted by the control system module, driving and analyzing coded information transmitted by a coder motor, generating odometer information after processing, analyzing information of the inertia measurement module, processing the information into a motion posture of the robot, integrating the generated acceleration twice, fusing the coder information through Kalman filtering to repair the odometer, sending an instruction to control the accurate rotation of the digital steering engine, enabling the mechanical arm to move to a specified position, calibrating the depth camera with the mechanical arm first, determining the conversion relation of a camera coordinate system relative to a mechanical arm base, converting a target object into a pose of the depth camera for providing the target object, finely adjusting the pose before the grabbing of the robot body, and then controlling the grabbing by vision; the wide-angle monocular camera is mainly used for acquiring external environment information as much as possible and detecting whether a target exists or not; the laser radar is mainly used for positioning and map building, the trolley independently explores and moves, and the map is continuously updated; the ultrasonic sensor provides sensing information for obstacle avoidance during autonomous movement, and is fused with the wide-angle monocular camera to provide physical information of point cloud; the support legs have a telescopic function and are used for slightly lifting the vehicle body after the grabbing pose is determined, so that wheels are not stressed, the trolley is prevented from deviating in the grabbing process, and the object is placed on the objective table after grabbing is completed; if the destination of the target object to be transported is located in the process of searching the target object, the destination is taken as a starting point and recorded into a built map, path planning is started, the trolley is moved to the transport destination, if the destination of the target object to be transported is not found, the transport destination is continuously and autonomously searched until the destination is found, then the target object is unloaded at the destination, and the information of the two position points is added into the map when the target object and the transport destination are searched, so that large-batch transport operation is facilitated;

the wheel is a self-made piece, a steel shaft sleeve is arranged in the middle of the wheel and used for mounting an axle, the main structure is made of 35 mass percent of glass fiber reinforced nylon ornylon 6 or nylon 66 material by using a compression molding process, and the size of the wheel can be determined according to the size of an actual vehicle body;

the encoding motor is a commercially available part, a GB37-520 direct current speed reducing motor with an encoder is adopted, the noise is relatively low, the jump is output for 330 times every time the encoding motor rotates for one circle, and then the running distance is calculated according to the diameter of the wheel and used as an odometer;

the vehicle body is a self-made piece, preferably a cuboid, and can be formed by cutting and welding aluminum alloy materials according to other shapes selected according to actual scenes, a position for loading other modules is reserved in the vehicle body, and a waterproof coating is coated on the outer part of the vehicle body, so that rainwater is prevented from entering the vehicle body, and corrosion can be prevented;

the control system module is a commercially available part, is arranged in the vehicle body and is used for data processing of various sensors, is an NVIDIA JETSON TX2 control module and is provided with a Ubuntu operating system in a Linux environment;

the inertial measurement module is a commercially available part, is an LPMS-IG1 RS232 metal shell IMU inertial measurement module, and integrates a three-axis gyroscope, a three-axis accelerometer, a three-axis magnetometer and an air pressure sensor;

the lithium battery is a commercially available part, has the capacity of 12v 25000mA, is arranged at a reserved position in the vehicle body and provides electric power for the whole robot system;

the single chip microcomputer is a self-made piece, and comprises a USB-to-serial port module, a 4-way encoder motor driving module, an 8-way PWM steering engine interface and an IMU interface, is used for motion control of the robot, and is provided with a self-programming control program;

the object stage is a self-made piece and is used for placing goods, the size and the dimension of the object stage can be determined according to the volume and the quantity of the goods actually transported, the external material is aluminum alloy, and the inner part of the object stage is pasted with an anti-collision pad;

the sensor support is a self-made piece made of aluminum alloy and used for bearing a depth camera, a wide-angle monocular camera and a laser radar;

the depth camera is a commercially available part, is of an Intel Real sensor D435i type, is used for detecting a target object, outputting an Euclidean distance relative to the camera, and is used for fine adjustment of the mobile trolley, after the camera is fixed in position, the relative position of the camera and a trolley body coordinate system is unchanged, and after the mechanical arm is calibrated, the vision control grabbing operation is carried out;

the wide-angle monocular camera is a commercially available part, has the model of large constant MER2-231-41U3C, has a lens LM6HC and is used for detecting a target object in a large range; firstly, calibrating internal and external parameters of a camera to obtain the internal and external parameters of the camera; then, carrying out combined calibration of the laser radar and camera external parameters to obtain a conversion matrix of the camera relative to the laser radar; a soft triggering mode is adopted, namely at the moment of the laser radar in the positive direction, an Application Programming Interface (API) provided by a camera software development kit is called to carry out soft triggering, and each frame is ensured to have a corresponding image and point cloud; finally, outputting the position of the target object for the trolley to move to the corresponding range;

the laser radar is a commercially available part, has the model of Velodyne16, is used for positioning and mapping, randomly scatters points in the environment, the points are calculated and connected to form a rapid search random tree, become a track along which the robot can run, generate the intersection points of the searched and unknown areas, update the map in real time by continuously updating the intersection points, continuously search for the target object by the wide-angle monocular camera in the autonomous movement process, adopt the path with the closer distance estimation value and the actual value as the optimal path after searching for the target object, and move the trolley to the position range of the target object;

the mechanical arm is a self-made piece, is used for bearing the mechanical arm and driving the mechanical arm to move together, is made of aluminum alloy materials, can realize five-axis movement, and solves the inverse kinematics of the mechanical arm;

the manipulator is a self-made piece and is used for grabbing goods; the shape of the hand is the same as that of a human hand, and the hand is provided with five fingers, each finger is formed by a straight metal pipe made of steel or aluminum material and a corrugated pipe at intervals, and the corrugated pipe is a joint and can be bent; the steel wire rope is arranged in each finger tube, the tightening and the loosening of the steel wire rope are controlled through the rotation of the rotating motor, so that the bending and the unfolding of the fingers are controlled, the five fingers are linked to grab and put down an object, and the design can provide smoother motion characteristics, more flexibility and better controllability for the manipulator, so that the manipulator is more flexible; the tail end of each finger is embedded into an ellipsoidal plastic body, the plastic body is made of polyether ether ketone (PEEK) materials and used for sealing the finger tube, one ends of steel wires are embedded into the plastic body, and the other ends of the steel wires are connected with a rotating motor;

the supporting leg self-made piece is characterized in that a main body is made of aluminum alloy and is solid, and an anti-skid gasket is fixed at the tail end of the supporting leg self-made piece and used for supporting the trolley during visual grabbing and retracting the trolley during moving;

the ultrasonic sensor is a commercially available part with the model of HRLV-MaxSonar-EZ MB1043 and provides obstacle information for emergency obstacle avoidance when the robot body moves;

the invention uses lithium battery as power source, after detecting the object, the robot moves to the area near the object, then uses depth camera to detect the position information of the object, judges whether the pose of the visual grabbing is satisfied, if not, fine-adjusts the position of the trolley, until finding the solution of inverse solution operation, grabs the object and places it on the objective table, at the same time marks the position, updates it in the map, when searching the object, finds the destination of the object needing to be carried, marks the center position of the destination, updates it in the newly-built map, at this moment, sets the grabbing position in the map as the starting point, uses the marked carrying destination as the target point, carries on path planning, moves the robot to the destination, carries on the unloading and placing operation of the goods, if the carrying destination is not found when searching the object, the trolley continues to explore, the map is continuously updated until the carrying destination is found, the destination is updated into the newly-built map, and then the target object is unloaded from the objective table and placed to the carrying destination; if a large amount of grabbing and carrying are needed, only the last positions need to be continuously exchanged, the trolley is enabled to move in a tracking mode, the position of the trolley is finely adjusted after the trolley reaches the designated position, and the trolley can timely take and unload the target object.

3. Compared with the prior art, the invention discloses a wheeled mobile intelligent logistics operation robot system, which has the following progress and advantages:

(1) the detection range is larger, the multi-sensor fusion operation is realized, the efficiency is better, and the accuracy is better.

(2) The supporting foot bottom adopts anti-skidding rubber pad, and the supporting legs is put down after the dolly removes the particular position for the automobile body is a little off the ground, and the arm snatchs the in-process more steadily, can not cause the wheel to slide because of the object is too heavy or the unbalance loading.

(3) The tracking function is set for the target and the carrying set point, and a large amount of calculation force is not needed for subsequent large-batch carrying.

(4) The manipulator adopts a novel flexible pipe-cable combined motion mode, is closer to the motion behavior of human hands, and has smoother motion characteristic, more flexibility and better controllability.

In a word, the system is an intelligent, multifunctional and high-precision robot system, can perform automatic goods searching, automatic moving, automatic loading and automatic unloading operations in closed parks such as warehouses, factories and the like, reduces manpower use, improves the efficiency and accuracy of logistics operation, and has very wide application prospect.

Drawings

FIG. 1 is a schematic diagram of the robotic system components of the present invention;

FIG. 2 is a schematic view of an ultrasonic sensor installation;

FIG. 3 is a schematic view of a vision sensor installation;

the symbols in the figures are as follows:

the system comprises a vehicle, a wheel, a 12-encoder motor, a vehicle body, a 21-control system module, a 22-inertia measurement module, a 23-lithium battery, a 24-single chip microcomputer, a 3-objective table, a 4-sensor support, a 5-depth camera, a 6-wide-angle monocular camera, a 7-laser radar, an 8-mechanical arm, a 9-mechanical arm, a 10-supporting leg and an 11-ultrasonic sensor.

Detailed Description

The embodiments of the invention will be described in further detail below with reference to the accompanying drawings:

as shown in the attached drawings, the invention discloses a wheeled mobile intelligent logistics operation robot system, which comprises the following parts: the system compriseswheels 1, acoding motor 12, avehicle body 2, acontrol system module 21, aninertia measurement module 22, alithium battery 23, asingle chip microcomputer 24, an objective table 3, asensor support 4, adepth camera 5, a wide-anglemonocular camera 6, alaser radar 7, amechanical arm 8, amanipulator 9,support legs 10 and anultrasonic sensor 11; the relationship between them is: thewheel 1 bears thevehicle body 2, thecoding motor 12 connected with thewheel 1 drives thewheel 1 to roll, corresponding coding information is output at the same time, the processed coding information is used as a odometer for the movement of thevehicle body 2, and thevehicle body 2 is used as a bearing body of each component; thecontrol system module 21 is used as a controller module of the whole system and is responsible for processing data collected by thedepth camera 5, the wide-anglemonocular camera 6 and thelaser radar 7 and sending corresponding instructions to thesinglechip 24 after processing; theinertia measurement module 22 is positioned at the mass center of thevehicle body 2 and is used as a judgment device of the motion posture of the robot and assists in correcting the odometer information; thelithium battery 23 is used as a power module of the whole system to provide electric power support for the whole system, thesingle chip 24 is responsible for receiving the information transmitted by thecontrol system module 21, driving and analyzing the coded information transmitted by theencoder motor 12, and generates odometer information after processing, analyzes the information of theinertia measurement module 22, processes the information into the motion attitude of the robot, meanwhile, the generated acceleration is integrated twice, mileometers are supplemented through Kalman filtering and encoder information fusion, instructions are sent to control the accurate rotation of the digital steering engine, so that themechanical arm 8 moves to a specified position, thedepth camera 5 needs to be calibrated with themechanical arm 8 first, the conversion relation of a camera coordinate system relative to a mechanical arm base is determined, converting the target object into a pose provided by thedepth camera 5, and controlling the pose by vision after the pose before the robot body is grabbed is finely adjusted; the wide-anglemonocular camera 6 is mainly used for acquiring external environment information as much as possible and detecting whether a target exists or not; thelaser radar 7 is mainly used for positioning and mapping, and meanwhile, the trolley independently explores and moves and continuously updates the map; theultrasonic sensor 11 provides sensing information for obstacle avoidance during autonomous movement, and is fused with the wide-anglemonocular camera 6 to provide physical information of point cloud; the supportinglegs 10 have a telescopic function and are used for slightly lifting the vehicle body after the grabbing pose is determined, so that thewheels 1 are not stressed, the deviation of the trolley in the grabbing process is prevented, and the object is placed on theobject stage 3 after grabbing is completed; if the destination of the target object to be transported is located in the process of searching the target object, the destination is taken as a starting point and recorded into a built map, path planning is started, the trolley is moved to the transport destination, if the destination of the target object to be transported is not found, the transport destination is continuously and autonomously searched until the destination is found, then the target object is unloaded at the destination, and the information of the two position points is added into the map when the target object and the transport destination are searched, so that large-batch transport operation is facilitated;

thewheel 1 is a self-made piece, a steel shaft sleeve is arranged in the middle of the wheel and used for mounting an axle, the main structure is made of 35 mass percent of glass fiber reinforced nylon ornylon 6 or nylon 66 material by using a compression molding process, and the size of the wheel can be determined according to the size of an actual vehicle body;

theencoding motor 12 is a commercially available part, a GB37-520 direct current speed reducing motor with an encoder is adopted, the noise is relatively low, the encoding motor outputs jump 330 times every time the encoding motor rotates for one circle, and then the running distance is calculated according to the diameter of the wheel and used as an odometer;

thevehicle body 2 is a self-made piece, preferably a cuboid, and can be formed by cutting and welding aluminum alloy materials according to other shapes selected according to actual scenes, positions for loading other modules are reserved in the vehicle body, and a waterproof coating is coated on the outer part of the vehicle body to prevent rainwater from entering the vehicle and prevent corrosion;

thecontrol system module 21 is a commercially available part, is installed inside thevehicle body 2, is used for data processing of various sensors, is a model NVIDIA JETSON TX2 control module, and is provided with an Ubuntu operating system in a Linux environment;

theinertial measurement module 22 is a commercially available part, is an LPMS-IG1 RS232 metal shell IMU inertial measurement module, and integrates a three-axis gyroscope, a three-axis accelerometer, a three-axis magnetometer and an air pressure sensor;

thelithium battery 23 is a commercially available part, has a capacity of 12v 25000mA, is arranged at a reserved position in the vehicle body, and provides electric power for the whole robot system;

thesingle chip microcomputer 24 is a self-made piece, and comprises a USB-to-serial port module, a 4-way encoder motor driving module, an 8-way PWM steering engine interface and an IMU interface, is used for motion control of the robot, and is provided with a self-programming control program;

theobject stage 3 is a self-made piece for placing goods, the size and the dimension of the object stage can be determined according to the volume and the quantity of the goods actually transported, the external material is aluminum alloy, and the inner part is pasted with an anti-collision pad;

thesensor support 4 is a self-made piece made of aluminum alloy and used for bearing a depth camera, a wide-angle monocular camera and a laser radar;

thedepth camera 5 is a commercially available part with the model of Intel Real sensor D435i, is used for detecting a target object, outputting an Euclidean distance relative to the camera, finely adjusting the moving trolley, keeping the relative position of the camera and a trolley body coordinate system unchanged after the camera is fixed, calibrating themechanical arm 8, and performing vision control grabbing operation;

the wide-anglemonocular camera 6 is a commercially available part, has the model of large constant MER2-231-41U3C, has a lens LM6HC and is used for detecting a target object in a large range; firstly, calibrating internal and external parameters of a camera to obtain the internal and external parameters of the camera; then, carrying out combined calibration of the laser radar and camera external parameters to obtain a conversion matrix of the camera relative to the laser radar; a soft triggering mode is adopted, namely at the moment of the laser radar in the positive direction, an Application Programming Interface (API) provided by a camera software development kit is called to carry out soft triggering, and each frame is ensured to have a corresponding image and point cloud; finally, outputting the position of the target object for the trolley to move to the corresponding range;

thelaser radar 7 is a commercially available part, has the model of Velodyne16, is used for positioning and mapping, randomly scatters points in the environment, the points are calculated and connected to form a rapid search random tree, become a track along which the robot can run, generate the intersection points of the searched and unknown areas, update the map in real time by continuously updating the intersection points, continuously search for the target object by the wide-angle monocular camera in the autonomous movement process, adopt the path with the closer distance estimation value and the actual value as the optimal path after searching for the target object, and move the trolley to the position range of the target object;

themechanical arm 8 is a self-made piece, is used for bearing themechanical arm 9 and drives themechanical arm 9 to move together, is made of aluminum alloy materials, can realize five-axis movement, and solves the inverse kinematics of the mechanical arm;

themanipulator 9 is a self-made piece and is used for grabbing goods; the shape of the hand is the same as that of a human hand, and the hand is provided with five fingers, each finger is formed by a straight metal pipe made of steel or aluminum material and a corrugated pipe at intervals, and the corrugated pipe is a joint and can be bent; the steel wire rope is arranged in each finger tube, the tightening and the loosening of the steel wire rope are controlled through the rotation of the rotating motor, so that the bending and the unfolding of the fingers are controlled, the five fingers are linked to grab and put down an object, and the design can provide smoother motion characteristics, more flexibility and better controllability for the manipulator, so that the manipulator is more flexible; the tail end of each finger is embedded into an ellipsoidal plastic body, the plastic body is made of polyether ether ketone (PEEK) materials and used for sealing the finger tube, one ends of steel wires are embedded into the plastic body, and the other ends of the steel wires are connected with a rotating motor;

the supportinglegs 10 are self-made pieces, the main body of each supporting leg is made of aluminum alloy and is solid, and an anti-skid gasket is fixed at the tail end of each supporting leg and used for supporting the trolley during visual grabbing and retracting the trolley during moving;

theultrasonic sensor 11 is a commercially available part with the model of HRLV-MaxSonar-EZ MB1043, and provides obstacle information for emergency obstacle avoidance when the robot body moves;

as shown in the attached drawing, the invention uses a lithium battery as a power source, after a target object is detected, a robot moves to a range near the target object, then a depth camera is adopted to detect the position information of the target object, whether the pose of visual grabbing is met is judged, if the pose of visual grabbing is not met, the position of a trolley is finely adjusted until a solution of inverse solution operation is found, the target object is grabbed and placed on an objective table, the position is marked and updated in a map, if a destination needing to be carried by the target object is found while the target object is searched, the central position of the destination is marked and updated in a newly-built map, the grabbing position in the map is set as a starting point, the marked carrying destination is used as a target point, path planning is carried out, the robot is moved to the destination, unloading and placing operation of goods is carried out, if the target object is searched, if the carrying destination is not found, the trolley continues to search, the map is continuously updated until the carrying destination is found, the destination is updated into a newly-built map, and then the target object is unloaded from the objective table and placed to the carrying destination; if a large amount of grabbing and carrying are needed, only the last positions need to be continuously exchanged, the trolley is enabled to move in a tracking mode, the position of the trolley is finely adjusted after the trolley reaches the designated position, and the trolley can timely take and unload the target object.

The present invention has been described in terms of specific embodiments, but is not limited to the above embodiments, and all technical solutions obtained by using similar structures and alternative materials according to the idea of the present invention fall within the protection scope of the present invention.

Claims

1. A wheeled mobile intelligent logistics operation robot system is characterized by comprising the following parts: the system comprises wheels, a coding motor, a vehicle body, a control system module, an inertia measurement module, a lithium battery, a single chip microcomputer, an objective table, a sensor support, a depth camera, a wide-angle monocular camera, a laser radar, a mechanical arm, a supporting leg and an ultrasonic sensor; the relationship between them is: the wheel bearing vehicle body is connected with a coding motor which drives the wheels to roll and outputs corresponding coding information, the processed coding information is used as a odometer for the movement of the vehicle body, and the vehicle body is used as a bearing body of each component; the control system module is used as a controller module of the whole system and is responsible for processing data collected by the depth camera, the wide-angle monocular camera and the laser radar and sending corresponding instructions to the single chip microcomputer after processing; the inertia measurement module is positioned at the mass center of the vehicle body and used as a judgment device of the motion attitude of the robot, and simultaneously assists in correcting the information of the odometer; the lithium battery is used as a power supply module of the whole system and provides electric power support for the whole system, the single chip microcomputer is responsible for receiving information transmitted by the control system module, driving and analyzing coded information transmitted by a coder motor, generating odometer information after processing, analyzing information of the inertia measurement module, processing the information into a motion posture of the robot, integrating the generated acceleration twice, fusing the coder information through Kalman filtering to repair the odometer, sending an instruction to control the accurate rotation of the digital steering engine, enabling the mechanical arm to move to a specified position, calibrating the depth camera with the mechanical arm first, determining the conversion relation of a camera coordinate system relative to a mechanical arm base, converting a target object into a pose of the depth camera for providing the target object, finely adjusting the pose before the grabbing of the robot body, and then controlling the grabbing by vision; the wide-angle monocular camera is mainly used for acquiring external environment information as much as possible and detecting whether a target exists or not; the laser radar is mainly used for positioning and map building, the trolley independently explores and moves, and the map is continuously updated; the ultrasonic sensor provides sensing information for obstacle avoidance during autonomous movement, and is fused with the wide-angle monocular camera to provide physical information of point cloud; the support legs have a telescopic function and are used for slightly lifting the vehicle body after the grabbing pose is determined, so that wheels are not stressed, the trolley is prevented from deviating in the grabbing process, and the object is placed on the objective table after grabbing is completed; if the destination of the target object to be transported is located in the process of searching the target object, the destination is taken as a starting point and recorded into a built map, path planning is started, the trolley is moved to the transport destination, if the destination of the target object to be transported is not found, the transport destination is continuously and autonomously searched until the destination is found, then the target object is unloaded at the destination, and the information of the two position points is added into the map when the target object and the transport destination are searched, so that large-batch transport operation is facilitated;

the wheel is a self-made piece, a steel shaft sleeve is arranged in the middle of the wheel and used for mounting an axle, the main structure is made of 35 mass percent of glass fiber reinforced nylon or nylon 6 or nylon 66 material by using a compression molding process, and the size of the wheel can be determined according to the size of an actual vehicle body;

the manipulator is a self-made piece and is used for grabbing goods; the shape of the hand is the same as that of a human hand, and the hand is provided with five fingers, each finger is formed by a straight metal pipe made of steel or aluminum material and a corrugated pipe at intervals, and the corrugated pipe is a joint and can be bent; the steel wire rope is arranged in each finger tube, the tightening and the loosening of the steel wire rope are controlled through the rotation of the rotating motor, so that the bending and the unfolding of the fingers are controlled, the five fingers are linked to grab and put down an object, and the design can provide smoother motion characteristics, more flexibility and better controllability for the manipulator, so that the manipulator is more flexible; the tail end of each finger is embedded into an ellipsoidal plastic body, the ellipsoidal plastic body is made of polyether ether ketone (PEEK) materials and used for sealing the finger tube, one end of each steel wire rope is embedded into the plastic body, and the other end of each steel wire rope is connected with a rotating motor.

2. The wheeled mobile intelligent logistics operation robot system of claim 1, wherein: the depth camera is a commercially available part, is of an Intel Real sensor D435i type, is used for detecting a target object, outputs an Euclidean distance relative to the camera, is used for fine adjustment of the moving trolley, keeps the relative position of the camera and a trolley body coordinate system unchanged after the camera is fixed, and performs vision control grabbing operation after calibrating the mechanical arm.

3. The wheeled mobile intelligent logistics operation robot system of claim 1, wherein: the wide-angle monocular camera is a commercially available part, has the model of large constant MER2-231-41U3C, has a lens LM6HC and is used for detecting a target object in a large range; firstly, calibrating internal and external parameters of a camera to obtain the internal and external parameters of the camera; then, carrying out combined calibration of the laser radar and camera external parameters to obtain a conversion matrix of the camera relative to the laser radar; a soft triggering mode is adopted, namely at the moment of the laser radar in the positive direction, an Application Programming Interface (API) provided by a camera software development kit is called to carry out soft triggering, and each frame is ensured to have a corresponding image and point cloud; and finally, outputting the position of the target object so that the trolley can move to the corresponding range.

4. The wheeled mobile intelligent logistics operation robot system of claim 1, wherein: the laser radar is a commercially available part, the model of the laser radar is Velodyne16, the laser radar is used for positioning and mapping, points are randomly scattered in the environment, the points are calculated and connected to form a rapid search random tree, the random tree becomes a track where a robot can run, cross points of searched and unknown areas are generated, a map is updated in real time by continuously updating the cross points, a wide-angle monocular camera continuously searches for a target object in the autonomous moving process, a path with a distance estimation value closer to an actual value is adopted as an optimal path after the target object is searched, and the trolley is moved to the position range of the target object.

5. The wheeled mobile intelligent logistics operation robot system of claim 1, wherein: the mechanical arm is a self-made piece and is used for bearing the mechanical arm and driving the mechanical arm to move together, the mechanical arm is made of aluminum alloy materials, five-axis movement can be achieved, and the inverse kinematics of the mechanical arm is solved.

6. The wheeled mobile intelligent logistics operation robot system of claim 1, wherein: the supporting leg is a self-made piece, the main body is made of aluminum alloy and is solid, and an anti-skid gasket is fixed at the tail end of the supporting leg and used for supporting the trolley when the trolley is visually grabbed and is folded when the trolley moves.

7. The wheeled mobile intelligent logistics operation robot system of claim 1, wherein: the ultrasonic sensor is a commercially available part, the model of the ultrasonic sensor is HRLV-MaxSonar-EZ MB1043, and obstacle information is provided for emergency obstacle avoidance when the robot body moves.

8. The wheeled mobile intelligent logistics operation robot system of claim 1, wherein: the method comprises the steps of taking a lithium battery as a power source, moving a robot to a range near a target object after the target object is detected, detecting position information of the target object by using a depth camera, judging whether the pose of visual grabbing is met or not, if the pose of visual grabbing is not met, finely adjusting the position of a trolley until a solution of inverse solution operation is found, grabbing the target object, placing the target object on an object stage, marking the position, updating the position in a map, marking the center position of the destination if a destination, which is required to be carried, of the target object is found while searching the target object, updating the center position in the newly-built map, setting the grabbing position in the map as a starting point, taking the marked carrying destination as a target point, planning a path, moving the robot to the destination, carrying and unloading and placing cargos, if no carrying destination is found while searching the target object, the trolley continues to explore, the map is continuously updated until the carrying destination is found, the destination is updated into the newly-built map, and then the target object is unloaded from the objective table and placed to the carrying destination; if a large amount of grabbing and carrying are needed, only the last positions need to be continuously exchanged, the trolley is enabled to move in a tracking mode, the position of the trolley is finely adjusted after the trolley reaches the designated position, and the trolley can timely take and unload the target object.