Force sensing-based follow-up trolley and control method thereof

Abstract

The invention discloses a follow-up trolley based on force perception and a control method thereof, and the follow-up trolley comprises a trolley body which comprises a driven wheel and a driving wheel; the follow-up sensing assembly comprises a rudderstock for an operator to operate, a stroke detection switch for detecting the traction of the rudderstock, and a force sensing assembly for measuring the pulling force on the two sides of the rudderstock; and the control box assembly calculates and controls the speed and the direction of the driving wheel according to the pulled information and the pulling force on the two sides. The control method comprises the steps that a travel switch signal is detected, and whether a traction intention exists is judged; tension values of the two force sensing assemblies are obtained, and the minimum tension value and the tension difference value are calculated; controlling the trolley speed according to the tension minimum value, and controlling the trolley direction according to the tension interpolation; and the driving wheels are controlled to execute corresponding actions to realize following movement of the trolley. The speed and the steering of the trolley are respectively controlled by measuring the magnitude and the difference value of the pulling forces on the two sides, and accurate control is realized by adopting a fuzzy control algorithm. The follow-up trolley is simple in structure, accurate in control, reliable in operation and suitable for complex environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent mobile vehicles, and in particular relates to an intelligent vehicle capable of sensing a person's movement intention and automatically following the person, and a control method thereof. Background Art

[0002] Following cars have broad application prospects in the fields of logistics, transportation, and commercial services, such as automatically following shopping carts in supermarkets, automatically following golf carts, and following luggage carts at airports. These following cars need to accurately sense the position and movement intention of people to achieve intelligent following functions.

[0003] At present, the following car mainly adopts the following sensing methods:

[0004] 1. Visual tracking: Identify the target person through the camera and analyze its position and movement status. However, this method is easily affected by factors such as ambient light and occlusion, and the recognition accuracy is low in complex environments.

[0005] 2. Ultrasonic tracking: Use ultrasonic ranging to determine the target position. However, ultrasonic waves are easily interfered by environmental noise and have limited positioning accuracy.

[0006] 3. Wireless signal following: Following via wireless signals such as RFID or Bluetooth. However, the signal is easily blocked and interfered with, and it is difficult to accurately sense the movement intention.

[0007] The above-mentioned prior art has the following main problems:

[0008] 1. The perception method is easily affected by the external environment and is not very reliable;

[0009] 2. It is difficult to accurately obtain the person's movement intention, resulting in insufficient follow-up response;

[0010] 3. The system is complex and the cost is high;

[0011] 4. Insufficient safety performance, prone to collision. Summary of the invention

[0012] The purpose of the present invention is to provide a follower vehicle based on force sensing and a control method thereof, which can directly sense a person's traction intention through a force sensor, realize a reliable following function, and overcome the problems existing in the prior art.

[0013] In a first aspect, the present invention provides a follower vehicle based on force perception, comprising:

[0014] Car body: including driven wheels and driving wheels;

[0015] Follow-up sensing component: including a rudder for the operator to operate, a travel detection switch for detecting the traction of the rudder, and a force sensing component for measuring the pulling force on both sides of the rudder;

[0016] Control box assembly: calculates and controls the speed and direction of the driving wheels based on the traction information and the pulling force on both sides.

[0017] In some optional embodiments of the present invention, the follow-up sensing component also includes a universal joint rotatably connected to the vehicle body, a pitch axis that can swing in the vertical plane and is hinged to the universal joint, the rudder is connected to the pitch axis, and the side walls on both sides of the pitch axis are respectively connected to one end of the force sensing component, and the other end of the force sensing component is fixed; the travel detection switch detects the displacement of the pitch axis; and the control box assembly determines whether the trolley is towed based on the displacement of the pitch axis.

[0018] Preferably, the pitch axis comprises a vertical portion connected to the rudder stock and a horizontal portion hinged to the universal shaft; an angle is provided between the horizontal portion and the vertical portion.

[0019] Further preferably, the angle between the horizontal portion and the vertical portion is a right angle.

[0020] In some optional embodiments of the present invention, the force sensing component includes an elastic member and a force measuring structure; one end of the force measuring structure is connected to one end of the elastic member, the other end of the force measuring structure is fixed, and the other end of the elastic member is connected to the rudder stock.

[0021] Preferably, the force measuring structure comprises a tension spring seat fixedly connected to the vehicle body, and the tension spring seat is connected to the elastic member via a multi-stage universal joint assembly, wherein a force sensor is provided between two adjacent universal joints.

[0022] Further preferably, the multi-stage universal joint assembly includes a primary universal joint, a secondary universal joint and a tertiary universal joint connected in sequence; one end of the force sensor is connected to the secondary universal joint, and the other end is connected to the tertiary universal joint; the tension spring seat is connected to the primary universal joint through a universal joint pin; and the tertiary universal joint is connected to the elastic member through a universal joint pin.

[0023] In a second aspect, the present invention provides a control method for the follower vehicle based on force perception applied to the first aspect, the control method comprising the following steps:

[0024] Detect the travel switch signal to determine whether there is a traction intention;

[0025] Obtain the tension values ​​of the two force sensing components, and calculate the minimum tension value and the tension difference;

[0026] The speed of the trolley is controlled according to the minimum pulling force, and the direction of the trolley is controlled according to the pulling force interpolation;

[0027] Control the driving wheel to perform corresponding actions to achieve the following movement of the car.

[0028] In some embodiments of the present invention, the speed of the vehicle is controlled according to the minimum pulling force, and the direction of the vehicle is controlled according to the pulling force interpolation, including:

[0029] The smaller pulling force value is used as the input of the speed fuzzy controller to output the speed value of the car;

[0030] The pulling force difference is used as the input of the angular velocity fuzzy controller to output the angular velocity value of the car;

[0031] The driving wheel speed and heading angle are calculated based on the vehicle speed and angular velocity.

[0032] In some optional embodiments of the present invention, the inclination angle of the trolley is also detected in real time; when the inclination angle is detected to exceed a preset threshold, the trolley is controlled to stop moving.

[0033] The beneficial effects of the present invention are:

[0034] Simple structure: Only two tension sensors are needed to obtain the person's traction intention. The structure is simple and compact, which reduces the system cost. Two symmetrically arranged force sensing components are used to obtain the person's traction intention. Each force sensing component achieves accurate force transmission through multi-stage universal joints and tension springs. The structural design is compact and reasonable, and it is easy to assemble and maintain.

[0035] Strong anti-interference ability: The force sensor is installed in a closed sensing box, and uses a multi-stage universal joint assembly to ensure accurate force transmission. It is not affected by external environmental factors such as light and noise, and can work stably in various complex environments.

[0036] Precise control: The fuzzy control algorithm is used to accurately control the speed and steering, making the movement of the car smoother; two force sensors are used to detect the left and right pulling forces respectively, and the fuzzy control algorithm is used according to the minimum pulling force and the difference to achieve precise control of speed and direction, with sensitive response and smooth following.

[0037] Safe and reliable: It is equipped with a tilt protection function, which automatically stops movement when the tilt angle is too large to avoid rollover accidents; a travel switch is set to detect the position of the pitch axis, and the tilt sensor monitors the vehicle posture in real time. It has multiple safety protection mechanisms such as overload protection and emergency stop protection.

[0038] Easy to operate: supports manual / automatic control modes, equipped with touch screen for parameter setting and status display, easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments disclosed in the present invention, the drawings of the embodiments will be briefly introduced below. These drawings are only used for illustrative purposes and are not intended to limit the protection scope of the present invention.

[0040] Figure 1This is a schematic diagram of a three-dimensional structure of a follower car based on force perception of the present invention. Figure 1 ;

[0041] Figure 2 This is a schematic diagram of a three-dimensional structure of a follower car based on force perception of the present invention. Figure 2 ;

[0042] Figure 3 The three-dimensional structure of the dynamic sensing component of the present invention is shown in FIG. Figure 1 ;

[0043] Figure 4 The three-dimensional structure of the dynamic sensing component of the present invention is shown in FIG. Figure 2 ;

[0044] Figure 5 It is a cross-sectional schematic diagram of the follow-up sensing component of the present invention;

[0045] Figure 6 It is a schematic diagram of the structure of the hand control box of the present invention;

[0046] In the figure: 1. Vehicle body (1.1. Box board; 1.2. Caster seat Ⅰ; 1.3. Fixed wheel Ⅰ; 1.4. Caster seat Ⅱ; 1.5. Fixed wheel Ⅱ; 1.6. Steering wheel Ⅰ; 1.7. Steering wheel seat Ⅰ; 1.8. Steering wheel Ⅱ; 1.9 Steering wheel seat Ⅱ);

[0047] 2. Follow-up sensing components (2.1, sensing box body; 2.2, universal joint; 2.3, pitch axis; 2.4, rudder; 2.5, handle; 2.6, force sensing component I; 2.7, force sensing component II; 2.8, travel switch; 2.9, tension spring pin);

[0048] 3. Control box components (3.1, battery; 3.2, power supply; 3.3, PLC controller; 3.4, relay; 3.5, fuse; 3.6, driver I; 3.7, driver II; 3.8, transmitter I; 3.9, transmitter II; 3.10, inclination sensor; 3.11, box);

[0049] 4. Manual control box (4.1, emergency stop button; 4.2, forward button; 4.3, reverse button; 4.4, left turn button; 4.5, right turn button; 4.6, manual-automatic switch button; 4.7, power-on button);

[0050] 2.1.1, bottom plate; 2.1.2, back plate; 2.1.3, small side plate I; 2.1.4, small side plate II; 2.1.5, large side plate I; 2.1.6, large side plate II; 2.1.7, front plate; 2.1.8, cover plate; 2.1.9, shaft clamp plate;

[0051] 2.6.1, tension spring seat Ⅰ; 2.6.2, universal joint pin Ⅰ; 2.6.3, primary universal joint Ⅰ; 2.6.4, secondary universal joint Ⅰ; 2.6.5, tertiary universal joint Ⅰ; 2.6.6, force sensor Ⅰ; 2.6.7, tension spring Ⅰ; 2.6.8, pin sleeve Ⅰ;

[0052] 2.7.1, tension spring seat II; 2.7.2, universal joint pin II; 2.7.3, primary universal joint II; 2.7.4, secondary universal joint II; 2.7.5, tertiary universal joint II; 2.7.6, force sensor II; 2.7.7, tension spring II; 2.7.8, pin sleeve II;

[0053] 3.11.1. Box top plate; 3.11.2. Box side plate I; 3.11.3. Box side plate II; 3.11.4. Box front plate; 3.11.5. Box rear plate; 3.11.6. Box columns; 3.11.7. Large observation window; 3.11.8. Small observation window. DETAILED DESCRIPTION

[0054] The technical solution of the present invention including the preferred technical solution is further described in detail below by means of the accompanying drawings and by listing some optional embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] Example 1

[0056] like Figures 1 to 5 As shown, this embodiment provides a force-sensing follower vehicle. The vehicle comprises a vehicle body 1, a follower sensing component 2, and a control box component 3. The vehicle body 1 is the main frame of the vehicle and is used to install other components; the follower sensing component 2 is used to sense the operator's motion intention; and the control box component 3 is used to realize the control function of the vehicle.

[0057] The vehicle body 1 includes a box plate 1.1, two fixed wheel assemblies and two steering wheel assemblies. The box plate 1.1 serves as the chassis support structure of the entire vehicle. The two fixed wheel assemblies include a caster seat I1.2, a fixed wheel I1.3, a caster seat II1.4 and a fixed wheel II1.5. The fixed wheel I1.3 is fixed to the lower side of the caster seat I1.2 by screws, and the upper side of the caster seat I1.2 is fixed to the bottom surface of the box plate 1.1 by screws; the fixed wheel II1.5 is fixed to one side of the caster seat II1.4 by screws, and the other side of the caster seat II1.4 is fixed to the bottom surface of the box plate 1.1 by screws. The two steering wheel assemblies include a steering wheel I1.6, a steering wheel seat I1.7 and a steering wheel II1.8, a steering wheel seat II1.9. The steering wheel I1.6 is fixed to the lower side of the steering wheel seat I1.7 by screws, and the upper side of the steering wheel seat I1.7 is fixed to the bottom surface of the box plate 1.1 by screws; the steering wheel II1.8 is fixed to the lower side of the steering wheel seat II1.9 by screws, and the upper side of the steering wheel seat II1.9 is fixed to the bottom surface of the box plate 1.1 by screws.

[0058] The follow-up sensing component 2 includes a sensing box body 2.1, a universal shaft 2.2, a pitch shaft 2.3, a rudder 2.4, a handle 2.5, two force sensing components and a travel switch 2.8. The sensing box body 2.1 includes a bottom plate 2.1.1, a back plate 2.1.2, a small side plate I2.1.3, a small side plate II2.1.4, a large side plate I2.1.5, a large side plate II2.1.6, a front plate 2.1.7, a cover plate 2.1.8 and a rotating shaft clamp plate 2.1.9. The back plate 2.1.2, the small side plate I2.1.3, the small side plate II2.1.4, the large side plate I2.1.5, the large side plate II2.1.6 and the front plate 2.1.7 are all connected to the bottom plate 2.1.1 and the cover plate 2.1.8 by screws to form a closed box structure.

[0059] The universal shaft 2.2 penetrates the induction box bottom plate 2.1.1, and the rotating shaft clamping plate 2.1.9 cooperates with the universal shaft annular groove for axial positioning; the rotating shaft clamping plate 2.1.9 is fixed to the induction box bottom plate 2.1.1 by screws. The pitch shaft 2.3 is connected to the universal shaft 2.2 through the pitch pin, and the tension spring pin 2.9 penetrates and is fixed on the pitch shaft 2.3. One end of the rudder bar 2.4 is connected to the universal shaft 2.2 by threading, and the other end is connected to the handle 2.5 by threading.

[0060] The force sensing component I2.6 includes a tension spring seat I2.6.1, a universal joint pin 2.6.2, a first-level universal joint I2.6.3, a second-level universal joint I2.6.4, a third-level universal joint I2.6.5, a force sensor I2.6.6, a tension spring I2.6.7, and a pin sleeve I2.6.8. One side of the tension spring seat I2.6.1 is fixed to the small side plate I2.1.3 of the induction box by screws, and the other side is connected to the first-level universal joint I2.6.3 through the universal joint pin 2.6.2; the first-level universal joint I2.6.3 is connected to the second-level universal joint I2.6.4 through the universal joint pin; the second-level universal joint I2.6.4 is threadedly connected to one end of the force sensor I2.6.6; one end of the third-level universal joint I2.6.5 is threadedly connected to the other end of the force sensor I2.6.6, and the other end is connected to the pin sleeve I2.6.8 through the universal joint pin; the two ends of the tension spring I2.6.7 are respectively hooked on the pin sleeve I2.6.8 and the tension spring pin 2.9.

[0061] The structure of force sensing component II2.7 is the same as that of force sensing component I2.6 and is installed on the other side of the induction box body 2.1. The travel switch 2.8 is fixed on the travel switch seat by screws to sense the position of the pitch axis 2.3; the travel switch seat is fixedly connected to the bottom plate of the induction box by screws.

[0062] The control box assembly 3 includes a battery 3.1, a power supply 3.2, a PLC controller 3.3, a relay 3.4, a fuse 3.5, a driver I 3.6, a driver II 3.7, a transmitter I 3.8, a transmitter II 3.9, an inclination sensor 3.10 and a box 3.11. The battery 3.1 is fixed to the vehicle box 1.1 by a battery block and a battery pressure plate, and its output end is connected to the input end of the power supply 3.2 through a fuse 3.5 and a relay 3.4. The power supply 3.2 is a DC power supply with a single input and multiple outputs, which supplies power to various components of the control system. The fuse 3.5 is used for system circuit overload protection.

[0063] The PLC controller 3.3 communicates with the transmitter I3.8, transmitter II3.9, driver I3.6, and driver II3.7 through the RS485 bus to complete the speed and direction control of the following car. Transmitters I3.8 and II3.9 are used for signal conversion of force sensor I2.6.6 and force sensor II2.7.6 respectively, and exchange data with the PLC controller 3.3.

[0064] Example 2

[0065] like Figure 6As shown, based on Example 1, the force sensing-based follower car disclosed in this embodiment further includes a hand control box 4, which is used for human-computer interaction. The hand control box 4 is provided with an emergency stop button 4.1, a forward button 4.2, a backward button 4.3, a left turn button 4.4, a right turn button 4.5, a manual-automatic switch button 4.6, and a power-on button 4.7. Among them:

[0066] Emergency stop button 4.1 is used to cut off the power supply of the system in an emergency;

[0067] The forward button 4.2 is used to control the forward movement of the trolley in manual mode;

[0068] The back button 4.3 is used to control the backward movement of the car in manual mode;

[0069] The left turn button 4.4 is used to control the left turn movement of the car in manual mode;

[0070] The right turn button 4.5 is used to control the right turn movement of the car in manual mode;

[0071] The manual-automatic switch button 4.6 is used to switch between the manual mode and the automatic following mode of the trolley;

[0072] The power button 4.7 is used to control the power on and off of the system.

[0073] Example 3

[0074] This embodiment provides a control method for a follower vehicle based on force sensing, comprising the following steps:

[0075] Step 1: System Initialization

[0076] After power-on, the system enters the initialization state, detects the working status of each sensor and actuator, and waits for the operator to select the working mode.

[0077] Step 2: Mode Selection

[0078] The system supports two working modes: manual mode and automatic following mode:

[0079] In manual mode, the movement of the car is directly controlled by the buttons on the hand control box;

[0080] In the automatic following mode, the system senses the operator's movement intention through the force sensor and automatically controls the car to follow.

[0081] Step 3: Force signal acquisition

[0082] In the automatic follow mode, when the operator pulls the handle:

[0083] The force sensor I2.6.6 collects the left tension value F1;

[0084] Force sensor II2.7.6 collects the right side tension value F2;

[0085] The signals of the two force sensors are converted by their respective transmitters and transmitted to the PLC controller.

[0086] Step 4: Motion Control

[0087] The PLC controller performs the following controls based on the collected force signal:

[0088] (1) Speed ​​control:

[0089] Take the smaller value Fmin of F1 and F2 as the input of speed control;

[0090] Map Fmin to the desired speed v through the speed fuzzy controller;

[0091] (2) Direction control:

[0092] Calculate the difference in left and right pulling forces ΔF = F1-F2;

[0093] Map ΔF to the desired angular velocity ω through the angular velocity fuzzy controller;

[0094] (3)Execution control:

[0095] According to the velocity v and angular velocity ω, the rotation speed and steering angle of the two steering wheels are calculated by inverse kinematics solution;

[0096] The steering wheel is controlled by the drive to perform the corresponding movement.

[0097] In summary, the control method of this embodiment is:

[0098] 1. Detect the tension value of the tension spring through two force sensors;

[0099] 2. Convert the tension value into a voltage signal through a transmitter;

[0100] 3. The PLC controller calculates the tension difference (ΔF) and the minimum tension value Fmin of the two force sensors based on the voltage signal;

[0101] 4. Take the smaller pulling force value Fmin as the input of the speed fuzzy controller and output the speed value v of the car;

[0102] 5. Use the pulling force difference ΔF as the input of the angular velocity fuzzy controller and output the angular velocity value ω of the car;

[0103] 6. Calculate the rotation speed and heading angle of the two steering wheels based on the speed value v and the angular velocity value ω.

[0104] Among them, the speed fuzzy controller adopts the following control rules:

[0105] When Fmin is less than the threshold F'1, the car remains stationary;

[0106] When Fmin is greater than the threshold F'1 and less than the threshold F'2, the car moves at a low speed;

[0107] When Fmin is greater than the threshold F'2, the car moves at normal speed.

[0108] The angular velocity fuzzy controller adopts the following control rules:

[0109] When |ΔF| is less than the threshold ΔF1, the car moves in a straight line;

[0110] When |ΔF| is greater than the threshold ΔF1 and less than the threshold ΔF2, the car turns slowly;

[0111] When |ΔF| is greater than the threshold ΔF2, the car turns quickly.

[0112] The workflow of the present invention is as follows:

[0113] (1) When the person pulls the handle to drive the pitch axis 2.3 to move, the signal of the travel switch 2.8 is set, and the control system obtains the person's pulling preparation intention.

[0114] (2) When traction continues, the pitch axis 2.3 continues to move, and the two force sensors convert the tension signal of the tension spring into a voltage signal. The voltage signal is converted into tension data by the transmitter and then fed back to the PLC controller 3.3.

[0115] (3) The PLC controller 3.3 calculates the smaller value Fmin based on the tension value F1 of force sensor I2.6.6 and the tension value F2 of force sensor II2.7.6 to control the acceleration and deceleration of the trolley, and controls the steering of the trolley based on the feedback tension difference △F (△F=F1–F2).

[0116] (4) When the person and the car are in the same direction, the tension values ​​of the two force sensors are basically the same, and the steering wheel maintains a straight-ahead state. When the person turns left, the rudder bar deviates to the left, and the tension difference △F is a negative value. The greater the turning angle, the smaller the difference. When the person turns right, the rudder bar deviates to the right, and △F is a positive value. The greater the turning angle, the greater the difference.

[0117] (5) When the person's movement speed increases, the angle between the rudder and the vertical direction increases, the tension spring is stretched, and Fmin increases accordingly; conversely, when the speed slows down, Fmin decreases.

[0118] Example 4

[0119] Based on Example 3, this example further adds a security protection function:

[0120] 1. Tilt protection: The tilt sensor detects the tilt of the car in real time. When the tilt exceeds the preset threshold, the control system immediately stops the car and sounds an alarm.

[0121] In some embodiments of the invention, the tilt protection:

[0122] (1) Monitor the inclination angle of the car in real time through the inclination sensor;

[0123] (2) Set the tilt angle threshold to ±15 degrees;

[0124] (3) When the tilt angle is detected to exceed the threshold: a. Stop the vehicle immediately; b. Display a warning message on the touch screen; c. The buzzer sounds an alarm.

[0125] 2. Overload protection: Real-time monitoring of motor current. When the current exceeds 1.5 times the rated value, the control system immediately cuts off the motor power supply and sounds an alarm.

[0126] 3. Emergency stop: Set an emergency stop button on the hand control box. When an emergency occurs, the operator can press the emergency stop button and the trolley will stop all movements immediately.

[0127] In some embodiments of the invention, the emergency stop:

[0128] (1) Emergency stop is triggered in the following situations: pressing the emergency stop button; detecting a collision signal; low battery; or system failure.

[0129] (2) After an emergency stop: cut off the drive power supply; brake all steering wheels; the system is locked and needs to be manually reset.

[0130] 4. Anti-collision protection: Ultrasonic sensors are installed in front and behind the car. When the obstacle is detected to be less than the safe distance, the control system will reduce the speed of the car or stop it.

[0131] Example 5

[0132] This embodiment provides a manual control mode. In the manual mode, the movement of the car is directly controlled by the buttons on the hand control box 4:

[0133] Press the forward button 4.2 to control the two steering wheels to rotate in the same direction;

[0134] Press the back button 4.3 to control the two steering wheels to reverse in the same direction;

[0135] Press the left turn button 4.4 to control the left steering wheel to slow down and the right steering wheel to speed up;

[0136] Press the right turn button 4.5 to control the right steering wheel to slow down and the left steering wheel to speed up.

[0137] Those skilled in the art will readily appreciate that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, replacements, improvements, etc. made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A follow-up vehicle based on force sensing, characterized in that: include: Body: including a driven wheel and a driving wheel; Follow-up sensing component: including a rudder for the operator to operate, a travel detection switch for detecting the traction of the rudder, and a force sensing component for measuring the pulling force on both sides of the rudder; Control box assembly: calculates and controls the speed and direction of the driving wheels based on the traction information and the pulling force on both sides.

2. The force sensing-based follower vehicle according to claim 1 is characterized in that: The follow-up sensing component also includes a universal joint rotatably connected to the vehicle body, a pitch axis that can swing in a vertical plane and is hinged to the universal joint, the rudder is connected to the pitch axis, and the side walls on both sides of the pitch axis are respectively connected to one end of the force sensing component, and the other end of the force sensing component is fixed; the travel detection switch detects the displacement of the pitch axis; the control box component determines whether the trolley is towed based on the displacement of the pitch axis.

3. The force sensing-based follower vehicle according to claim 2 is characterized in that: The pitch axis comprises a vertical portion connected to the rudder stock and a horizontal portion hinged to the universal shaft; an angle is arranged between the horizontal portion and the vertical portion.

4. The force sensing-based follower vehicle according to claim 3 is characterized in that: The included angle between the horizontal portion and the vertical portion is a right angle.

5. The force sensing-based follower vehicle according to any one of claims 1 to 4, characterized in that: The force sensing component comprises an elastic member and a force measuring structure; one end of the force measuring structure is connected to one end of the elastic member, the other end of the force measuring structure is fixed, and the other end of the elastic member is connected to the rudder stock.

6. The force sensing-based follower vehicle according to claim 5 is characterized in that: The force measuring structure comprises a tension spring seat fixedly connected to the vehicle body, and the tension spring seat is connected to the elastic member through a multi-stage universal joint assembly, wherein a force sensor is arranged between two adjacent universal joints.

7. The force sensing-based follower vehicle according to claim 6 is characterized in that: The multi-stage universal joint assembly includes a primary universal joint, a secondary universal joint and a tertiary universal joint connected in sequence; one end of the force sensor is connected to the secondary universal joint, and the other end is connected to the tertiary universal joint; the tension spring seat is connected to the primary universal joint through a universal joint pin; the tertiary universal joint is connected to the elastic member through a universal joint pin.

8. A control method for a follower vehicle based on force sensing as claimed in any one of claims 1 to 7, wherein the control method is characterized in that: The following steps are involved: Detect the travel switch signal to determine whether there is a traction intention; Obtain the tension values ​​of the two force sensing components, and calculate the minimum tension value and the tension difference; The speed of the trolley is controlled according to the minimum pulling force, and the direction of the trolley is controlled according to the pulling force interpolation; Control the driving wheel to perform corresponding actions to achieve the following movement of the car.

9. The control method according to claim 1, characterized in that: The speed of the car is controlled according to the minimum pulling force, and the direction of the car is controlled according to the pulling force interpolation, including: The smaller pulling force value is used as the input of the speed fuzzy controller to output the speed value of the car; The pulling force difference is used as the input of the angular velocity fuzzy controller to output the angular velocity value of the car; The driving wheel speed and heading angle are calculated based on the vehicle speed and angular velocity.

10. The control method according to claim 8 or 9, characterized in that: It also includes real-time detection of the inclination angle of the car; when it is detected that the inclination angle exceeds a preset threshold, the car is controlled to stop moving.

Images