Agricultural chassis walking device based on wheel train profiling and torque feedback and control method
By using an agricultural chassis walking device based on wheel system contouring and torque feedback, the problems of non-compact chassis structure and insufficient obstacle avoidance ability of agricultural robots are solved, achieving higher passability and stability, ensuring wheel contact with the road surface, and providing precise navigation and obstacle avoidance functions.
Patent Information
- Application Number
- CN202511709177.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2026-01-02
AI Technical Summary
Existing agricultural robots have chassis structures that are not compact enough, have insufficient mobility, and have large contouring mechanisms, which leads to problems such as high straight-line deviation rate, slow steering, and insufficient obstacle avoidance ability when walking in the field.
The agricultural chassis walking device, based on wheel system contouring and torque feedback, includes a walking module, a frame, and a control box. It utilizes a navigation module, a wheel system anti-collision module, and a motor torque feedback module, and achieves dynamic torque adjustment and obstacle avoidance control through a torque sensor and a motor controller. Combined with an internal suspension design, it can adapt to different ground conditions.
It improves the structural compactness and driving stability of the chassis, enhances passability and comfort, ensures that the wheels are always in contact with the road surface, reduces the suspension rate, and achieves precise navigation and obstacle avoidance capabilities.
Smart Images
Figure CN121246960A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of agricultural robot technology, in particular to an agricultural chassis walking device based on wheel train profiling and torque feedback and a control method. BACKGROUND
[0002] At present, for the agricultural operation scene, the existing agricultural robot chassis structure layout is not compact enough, resulting in insufficient field passability. At the same time, due to the working conditions of the agricultural operation scene, the ground conditions are diverse, including grassland, muddy road, land, gravel road, and hardened road, which brings certain challenges to the passability of the chassis. In the case of normal walking and climbing operation, it is also necessary to realize multi-scene turning, and each group of wheel train modules can profile operation according to the ground conditions to improve the stability and passability of the chassis walking. However, in the existing agricultural chassis equipment, the profiling mechanism has a large volume, so that the overall structure is large, which is not conducive to the machine to shuttle in the narrow channel. In addition, in the process of straight-line walking and turning control of the agricultural robot chassis, the average deviation rate of straight-line walking in the field environment is high, the turning actuator has a hysteresis phenomenon, and the ground obstacles cannot be identified and avoided in time. SUMMARY
[0003] In view of the problems of large volume of profiling mechanism, insufficient passability, and insufficient straight-line walking, turning, and obstacle avoidance control of the chassis walking device in the existing technology, the present application provides an agricultural chassis walking device based on wheel train profiling and torque feedback, which comprises a walking module, a skeleton and a control box body arranged on the skeleton; a navigation module and a URCU controller are arranged in the control box body; The walking module comprises a wheel train, a wheel fork, a guide column and a walking column; The walking column is fixed on the skeleton, a spline shaft is arranged in the walking column, a steering motor for controlling the rotation of the spline shaft is installed on the walking column, the upper part of the spline shaft is connected with the steering motor through a steering transmission shaft, the lower part of the spline shaft is arranged in the guide column which can move up and down along the spline shaft, the other end of the guide column is fixed on the wheel fork, the wheel fork is fixed on the two sides of the wheel train through an axle respectively, and a distance for the required upward movement of the wheel train profiling is left between the bottom of the walking column and the wheel fork; A compression spring is sleeved in the walking column, one end of the compression spring is limited in the guide column, and the other end is limited in the top of the walking column; A torque sensor is arranged on the axle, a motor controller MCU is arranged on the steering motor, and the motor controller MCU and the torque sensor are connected with the URCU controller.
[0004] Further, the steering motor is installed on the walking column through a steering motor mounting seat, and the steering transmission shaft is nested in the steering motor mounting seat; the steering transmission shaft outer ring is provided with a protrusion, and a groove for rotation of the protrusion is formed in the steering motor mounting seat, and an angle limiting strip matched with the protrusion is arranged on the inner wall of the groove.
[0005] Further, a second bearing is installed on the spline shaft near the top of the walking column; a pair of first bearings are arranged at the bottom of the walking column and installed on the guide column, and the first bearings are separated by a bushing, and the first bearings and the bushing are provided with bearing sleeves.
[0006] Further, a graphene brass sleeve is installed on the bearing sleeve at the position of the pair of first bearings, and a steel sleeve is arranged outside the graphene brass sleeve for isolation from the inner wall of the walking column, and the steel sleeve is fixed to the bottom of the walking column.
[0007] Further, the inner walls of the bearing sleeve, the graphene brass sleeve and the steel sleeve are all provided with flow guide grooves for lubricant flow, and the surface of the walking column is provided with oil nozzles in communication with the flow guide grooves.
[0008] Further, an anti-collision bracket is arranged around the wheel system, the anti-collision bracket is fixed to the wheel shaft, and an anti-collision strip in communication with the control box is arranged on the anti-collision bracket, the anti-collision strip includes a front anti-collision strip, a rear anti-collision strip, a left anti-collision strip and a right anti-collision strip.
[0009] The application also provides an agricultural chassis walking control method based on wheel system profiling and torque feedback, which is realized through the navigation module, the wheel system anti-collision module, the motor torque feedback module and the URCU controller, wherein the wheel system anti-collision module includes the anti-collision strip, and the motor torque feedback module includes the torque sensor and the motor controller MCU; the torque sensor is used to collect the actual torque of the wheel system in real time, the motor controller MCU is used to regulate and control the output torque and the rotating speed of the motor, and the estimated actual torque can be obtained through the electrical parameter back calculation algorithm of the steering motor; the sampling frequency of the motor torque feedback module reaches the millisecond level, and the error ΔT between the actual torque collected by the torque sensor and the estimated actual torque at the same time is less than or equal to 5%; In the case of no large target obstacle in the walking route, the navigation module detects the position of the chassis walking device in real time. If it is identified that the chassis walking device deviates from the navigation path or receives the steering walking instruction of the URCU controller, the steering walking control mode is started until the chassis walking device is completely corrected and returns to the straight walking reference. If the walking device deviates due to the change of the unilateral road condition, the straight walking control mode is started to balance the torque of the two sides of the chassis walking device. In the case of large target obstacle in the walking route, the wheel train anti-collision module triggers the wheel train anti-collision control mode.
[0010] Further, the steering walking control mode comprises the following steps: S1: The actual torque corresponding to the wheel train is collected in real time through the torque sensor; S2: The target torque of the two sides of the chassis walking device is set according to the required steering curvature, direction and amplitude planned by the navigation module, and the target torque difference of the two sides is formed; S3: The torque correction amount is calculated, and the motor controller MCU dynamically adjusts the output of the steering motor on the two sides according to the torque correction amount, wherein the torque correction amount is the difference between the actual torque and the target torque; S4: The corrected torque of the two sides of the chassis walking device is continuously monitored through the torque sensor. If the corrected torque of the two sides reaches the target torque and satisfies ΔT≤5%, the current output of the steering motor on the two sides is maintained; otherwise, S1-S3 is repeated until the target torque of the two sides is reached; S5: The position of the chassis walking device is continuously detected by the navigation module. If the chassis walking device gradually returns to the preset path, the target torque difference of the two sides is gradually reduced until the chassis walking device is completely corrected. If the chassis walking device has been completely corrected, the same target torque of the two sides is maintained, and the straight line reference of the walking is returned.
[0011] Further, the straight walking control mode comprises the following steps: S1: The actual torque corresponding to the wheel train is collected in real time through the torque sensor; S2: The target torque of the two sides of the chassis walking device is set according to the weight of the chassis walking device and the preset speed. The actual torque and the target torque are compared, and the deviation direction is judged; S3: The torque correction amount is calculated, and the motor controller MCU dynamically adjusts the output of the steering motor on the two sides according to the torque correction amount, wherein the torque correction amount is the difference between the actual torque and the target torque; S4: The corrected torque of the two sides of the chassis walking device is continuously monitored through the torque sensor. If the corrected torque of the two sides reaches the target torque and satisfies ΔT≤5%, the current output of the steering motor on the two sides is maintained; otherwise, S1-S3 is repeated until the target torque of the two sides is reached; m, and ΔT≤5%, the current two sides of the steering motor output is maintained; otherwise, repeat S1-S3 until the target torque of both sides is reached.
[0012] Further, the wheel train anti-collision control mode is: When the wheel train is walking forward, after the front anti-collision strip contacts the obstacle, the URCU controller sends a stop or backward walking instruction to the wheel train; When the wheel train is walking backward, after the rear anti-collision strip contacts the obstacle, the URCU controller sends a stop or forward walking instruction to the wheel train; When the wheel train is turning left, after either of the left anti-collision strip and the front anti-collision strip contacts the obstacle, the URCU controller sends a stop or right turning avoidance instruction to the wheel train; When the wheel train is turning right, after either of the right anti-collision strip and the front anti-collision strip contacts the obstacle, the URCU controller sends a stop or left turning avoidance instruction to the wheel train.
[0013] Compared with the prior art, the present application has the following beneficial effects: Compared with the existing external large profiling mechanism, the suspension components are placed in the chassis, releasing the space below the chassis, reducing the protrusion in the wheel arch, and improving the compactness by 40%. At the same time, it can adapt to the ups and downs of different surfaces such as grassland, muddy road, and rocky road (the maximum profiling stroke can reach 8 cm), reduce the suspension rate of the wheel train, softly filter bumps, and improve the walking stability by more than 60%. Since each walking module is provided with a built-in suspension, independent profiling of each wheel train can be achieved, and the "adhesion type" passing on rough roads can maximize the contact of the four wheels with the road surface (reduce suspension), improve the grip (avoid slipping), and reduce the roll and pitch amplitude of the vehicle body, making the driving more stable and taking into account the passability and comfort.
[0014] Through the coordination of the motor torque feedback module, the basis for dynamic adjustment of straight walking and turning is provided: when walking straight, it is a "balancer" that eliminates the torque difference on both sides to resist road interference and maintain straight walking; when turning, it is an "actuator" that creates a controllable torque difference according to the navigation requirements to actively pull the chassis walking device back to the preset path; the whole process realizes the goal of "path not deviating, straight walking stable" through the closed loop of "perception - decision - adjustment - verification", providing a guarantee for precise navigation walking. In addition, the wheel train anti-collision setting is made, which can effectively execute avoidance or braking instructions when encountering collision risks. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 The present application is a schematic diagram of the overall structure; Figure 2Structure diagram of walking module of the present application; Figure 3 Structure diagram of walking module of the present application; Figure 2 Internal section view of walking upright column in A-A direction of the present application; Figure 4 Connection diagram of each part of spline shaft top of the present application; Figure 5 Structure diagram of wheel train anti-collision structure of the present application; In the figure: 1, walking module; 2, framework; 3, control box; 4, travel limiting block; 5, spline shaft; 6, steering motor; 7, steering transmission shaft; 8, first bearing; 9, compression spring; 10, bearing sleeve; 11, wheel train; 12, wheel fork; 13, guide upright column; 14, walking upright column; 15, wheel axle; 16, graphene brass sleeve; 17, steel sleeve; 18, second bearing; 19, anti-collision support; 20, flow guide groove; 21, bushing; 22, upper mounting flange; 23, lower mounting flange; 24, connecting plate; 25, protruding block; 26, angle limiting strip; 27, first locking bolt; 28, oil nozzle; 29, end cover; 30, steering motor mounting seat; 31, second locking bolt; 32, flat key; 33, front anti-collision strip; 34, rear anti-collision strip; 35, left anti-collision strip; 36, right anti-collision strip. DETAILED DESCRIPTION
[0016] In order to make the person skilled in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.
[0017] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. The terms "upper", "lower", "front", "rear", "top", "bottom", and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the devices or parts referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.
[0018] As Figure 1As shown, the agricultural chassis walking device based on wheel system contouring and torque feedback includes a walking module 1, a frame 2, and a control box 3 mounted on the frame 2; the control box 3 is equipped with a navigation module and a URCU controller. like Figure 2 As shown, the walking module 1 includes a wheel system 11, wheel forks 12, guide columns 13 and walking columns 14; like Figures 1-4 As shown, the walking column 14 is fixed on the frame 2. A spline shaft 5 is provided inside the walking column 14. A steering motor 6 for controlling the rotation of the spline shaft 5 is installed on the walking column 14. The upper part of the spline shaft 5 is connected to the steering motor 6 through a steering transmission shaft 7. The lower part of the spline shaft 5 is set in a guide column 13 that can move up and down along the spline shaft 5. The other end of the guide column 13 is fixed to the wheel fork 12. The two sides of the wheel fork 12 are fixed to the two sides of the wheel system 11 through wheel axles 15 respectively. A distance is left between the bottom of the walking column 14 and the wheel fork 12 for the wheel system to rise as required for contouring. A compression spring 9 is fitted inside the walking column 14. One end of the compression spring 9 is limited to the guide column 13, and the other end is limited to the top of the walking column 14. A torque sensor is installed on the wheel axle 15, and a motor controller MCU is installed on the steering motor 6. Both the motor controller MCU and the torque sensor are connected to the URCU controller.
[0019] The principle of gear train contouring in this application is as follows: The spline shaft 5 and the guide column 13 work together, combined with the compression spring 9 located in the travel column 14, to form an independent suspension unit for each travel module 1.
[0020] Through the independent suspension unit in the walking module 1, the wheel system 11 can flexibly "follow" (contour) the undulations of the road surface. Due to the weight of the frame 2 and the control box 3, the compression spring 9 is partially compressed when it is installed in the walking column 14. When a wheel system 11 runs over a bump (or gets stuck in a pothole), the wheel system 11 will first be subjected to the vertical force of the road surface (the bump pushes the wheel system 11 upward, and the pothole causes the wheel system 11 to fall downward due to gravity). For example, when encountering a bump, the guide column 13 will move upward, and the wheel system 11 will rise accordingly; when encountering a pothole, the guide column 13 will move downward under the action of the compression spring 9, and the wheel system 11 will fall accordingly, realizing the contouring of "the wheel system 11 undulating synchronously with the road surface". The relative sliding between the spline shaft 5 and the guide column 13 adapts to different contouring amounts.
[0021] In addition to limiting the upward distance of the guide column 13 in the travel column 14 by the distance between the bottom of the travel column 14 and the wheel fork 12, as another contouring safety limiting method, the top of the guide column 13 is fixed with a travel limit block 4 that can move together with the guide column 13 on the spline shaft 5 to limit the maximum upward movement of the guide column 13.
[0022] Compared with the existing external large profiling mechanism, the suspension components in the application are placed on the chassis, releasing the space below the chassis, reducing the protrusion in the wheel arch, and improving the compactness by 40%. The built-in design isolates the sand, reduces the collision risk, protects the core components such as shock absorbers, and prolongs the service life of the components. At the same time, it can adapt to the ups and downs of different surfaces such as grassland, muddy road, and sandy road (the maximum profiling stroke can reach 8 cm), reducing the suspension rate of the wheel train, softening the bumps, and improving the walking stability by more than 60%.
[0023] Since each walking module is provided with a built-in suspension, independent profiling of each wheel train can be achieved, and the "adhesion type" through on rough roads can maximize the guarantee that the four wheels are always in contact with the road surface (reducing suspension), which not only improves the grip (avoids slipping), but also reduces the roll and pitch amplitude of the vehicle body, making the driving more stable, and balancing the passability and comfort.
[0024] The principle of wheel train steering in the application is as follows: When the wheel train needs to be steered, the steering motor 6 provides steering power, and the steering motor 6 drives the spline shaft 5 to rotate through the steering transmission shaft 7, since the spline can transmit torque, the spline shaft 5 drives the guide column 13 to steer, thereby driving the steering of the overall walking module 1.
[0025] In the embodiment, the above-mentioned wheel train profiling and steering functions are achieved through the following specific structures: As shown in Figure 2 and Figure 3 , the walking column 14 is fixed to the framework 2 through the upper mounting flange 22 and the lower mounting flange 23, and the upper mounting flange 22 and the lower mounting flange 23 are fixed through the connecting plate 24, and the lower part of the lower mounting flange 23 is provided with an end cover 29. The upper mounting flange 22 is provided with a steering motor mounting seat 30, and the steering motor 6 is mounted on the walking column 14 through the steering motor mounting seat 30. As shown in Figure 4 , the steering transmission shaft 7 is nested in the steering motor mounting seat 30, the outer circle of the steering transmission shaft 7 is provided with a protrusion 25, and the steering motor mounting seat 30 is provided with a groove for the rotation of the protrusion 25, and the inner wall of the groove is provided with an angle limiting strip 26 matched with the protrusion 25, so that the rotation range of the steering transmission shaft 7 is limited within 360°. The mechanical angle limiting can effectively prevent the problem of winding of the walking wheel train caused by multiple rotations of the encoder on the steering motor 6. The steering transmission shaft 7 and the spline 5 shaft are connected by a flat key 32, which can ensure that the steering motor 6 installed with the steering transmission shaft 7 only bears radial force and does not bear axial force, thereby maximizing the protection of the steering motor 6.
[0026] The spline shaft 5 near the top of the walking column 14 is provided with a second bearing 18 mounted by a first locking bolt 27, and the second bearing 18 in the embodiment is a deep groove ball bearing.
[0027] The bottom of the walking column 14 is provided with a pair of first bearings 8 mounted on the guide column 13, and the pair of first bearings 8 are separated by a bushing 21. The upper first bearings 8 are fixed to the guide column 13 by first locking bolts 31. In this embodiment, the first bearings 8 are needle thrust bearings. In order to ensure the stability of the walking column 13 and the first bearings 8 moving in the walking column 14, the first bearings 8 and the bushing 21 are provided with a bearing sleeve 10, which protects and assists in fixing the first bearings 8.
[0028] In order to ensure the stability of the guide column 13 moving up and down and turning in the walking column 14, the bearing sleeve 10 is provided with a graphene brass sleeve 16 at the position of the pair of first bearings 8, and the graphene brass sleeve 16 is provided with a steel sleeve 17 for isolation from the inner wall of the walking column 14, and the steel sleeve 17 is fixed to the bottom of the walking column 14. The steel sleeve 17 has a guiding effect on the guide column 13 and the first bearings 8 moving up and down in the walking column 14. The graphene brass sleeve 16 is arranged between the bearing sleeve 10 and the steel sleeve 17, which not only has high wear resistance and low damping, but also can provide stable structural support. When the wheel train 11 encounters a ground protrusion (or falls into a pit), the guide column 13 moves up (or down), and the pair of first bearings 8 and the bearing sleeve 10 and the graphene brass sleeve 16 outside them move up (or down) as a whole, and relative sliding occurs with the steel sleeve 17.
[0029] In order to ensure the smoothness of the sliding between the bearing sleeve 10, the graphene brass sleeve 16 and the steel sleeve 17, and reduce the sliding friction between them, the inner walls of the bearing sleeve 10, the graphene brass sleeve 16 and the steel sleeve 17 are provided with flow grooves 20 for lubricant flow, and the surface of the walking column 14 is provided with oil nozzles 28 in communication with the flow grooves 20.
[0030] There are various ways to fix and limit the compression spring 9 in the walking column 14. In this embodiment, a limiting groove matching the upper end of the compression spring 9 is formed in the inner wall of the upper mounting flange 22, and a limiting groove matching the lower end of the compression spring 9 is formed in the top of the bearing sleeve 10 at the top of the graphene brass sleeve 16 away from the yoke 12. The spring support seat can also be provided on the inner wall of the upper mounting flange 22 and the guide column 13 to limit the compression spring 9.
[0031] As shown in Figure 5 In order to enhance the protection of the wheel train 11, a crash guard 19 is provided around the wheel train 11, and the crash guard 19 is fixed to the wheel shaft 15. The crash guard 19 is provided with a crash strip in communication with the control box 3, and the crash strip includes a front crash strip 33, a rear crash strip 34, a left crash strip 35 and a right crash strip 36. It should be noted that "front", "rear", "left" and "right" here are relative to the forward direction of the chassis walking device.
[0032] In order to realize the accurate walking of the agricultural chassis walking device according to the navigation path and timely obstacle avoidance, the application proposes a control method of the agricultural chassis walking device based on wheel train profiling and torque feedback, which is realized through a navigation module, a wheel train anti-collision module, a motor torque feedback module and a URCU controller. The wheel train anti-collision module includes an anti-collision strip, the motor torque feedback module includes a torque sensor and a motor controller MCU, the torque sensor is used to collect the actual torque of the wheel train 11 in real time, the motor controller MCU is used to regulate and control the output torque and speed of the motor, and the estimated actual torque is obtained through the electrical parameter back calculation algorithm of the steering motor 6. The sampling frequency of the motor torque feedback module reaches the millisecond level, and the error ΔT between the actual torque collected by the torque sensor and the estimated actual torque at the same time is less than or equal to 5%. The motor controller MCU can back calculate the estimated actual torque through the electrical parameters (current, voltage, speed) of the steering motor 6 and the motor mathematical model, ensure the torque tracking accuracy, identify the torque deviation, and provide a basis for dynamic adjustment.
[0033] In the case that there is no large target obstacle in the walking route, the navigation module detects the position of the chassis walking device in real time. If it is identified that the chassis walking device deviates from the navigation path or receives the steering walking instruction of the URCU controller, the steering walking control mode is started until the chassis walking device is completely corrected and returns to the straight walking reference. If the posture of the wheel train or the walking device body on one side is abnormal due to the change of the road condition on one side, the straight walking control mode is started to balance the torques on both sides of the chassis walking device. In the case that there is a large target obstacle in the walking route, the wheel train anti-collision module triggers the wheel train anti-collision control mode.
[0034] The wheel train anti-collision control mode is as follows: When the wheel train 11 walks forward, after the front anti-collision strip 33 contacts the obstacle, the URCU controller sends a stop or backward walking instruction to the wheel train 11. When the wheel train 11 walks backward, after the rear anti-collision strip 34 contacts the obstacle, the URCU controller sends a stop or forward walking instruction to the wheel train 11. When the wheel train 11 turns left, after any one of the left anti-collision strip 35 and the front anti-collision strip 33 contacts the obstacle, the URCU controller sends a stop or right turning avoidance instruction to the wheel train 11. When the wheel train 11 turns right, after any one of the right anti-collision strip 36 and the front anti-collision strip 33 contacts the obstacle, the URCU controller sends a stop or left turning avoidance instruction to the wheel train 11.
[0035] Through the setting of the wheel train anti-collision, the avoidance or braking instruction can be effectively executed when the collision risk is encountered.
[0036] Embodiment 1 The steering walking control mode includes the following steps: S1: Real-time collection of actual torque corresponding to wheel train 11 through torque sensor; S2: Set different target torques on both sides of the chassis walking device according to the required steering curvature, direction and amplitude planned by the navigation module, and form a target torque difference on both sides; S3: Calculate torque correction amount, and dynamically adjust the output of the two sides steering motor 6 according to the torque correction amount, wherein the torque correction amount is the difference between the actual torque and the target torque; S4: Continuously monitor the corrected torque on both sides of the chassis walking device through the torque sensor, if the corrected torque on both sides reaches the target torque, and satisfies ΔT≤5%, maintain the current output of the two sides steering motor 6; Otherwise, repeat S1-S3 until the target torque on both sides is reached; S5: The navigation module continuously detects the position of the chassis walking device, if the chassis walking device gradually returns to the preset path, gradually reduce the target torque difference on both sides, until the chassis walking device is completely corrected; If the chassis walking device has been completely corrected, keep the same target torque on both sides, and return to the straight line reference.
[0037] This embodiment takes navigation steering correction as an example: the navigation module (such as GPS, laser radar) detects that the chassis walking device deviates from the preset path (such as 10 cm left deviation when driving straight, or insufficient steering when required to navigate), and the motor torque feedback module will cooperate with the navigation module to control, and realize path correction by "actively creating torque difference".
[0038] The chassis walking device in this embodiment is analyzed as follows: The actual torque of the wheel train 11 on both sides of the current chassis walking device is 40N m, but the current position of the chassis walking device deviates to the right, and needs to be corrected to the left by 8 cm. The implementation process of navigation steering correction is as follows: S1: The actual torque of the four wheel trains 11 on both sides is 40N m, which is collected by the torque sensor in real time; S2: Since the chassis walking device currently deviates to the right, it needs to be corrected to the left by 8 cm, and needs to generate a steering torque of "slightly faster left wheel and slightly slower right wheel". The motor torque feedback module sets the target torque of the left side to 45N m, and the target torque of the right side to 35N m, forming a target torque difference of 10N m between the left and right.
[0039] It should be noted that the smaller the correction amplitude (such as only 2 cm correction), the smaller the torque difference (such as 42N m on the left and 38N m), avoid excessive correction; the greater the amplitude, the appropriate increase in torque difference (but need to be controlled in the safety range, to prevent sudden turn).
[0040] S3: Calculate the torque correction, the left side torque correction is 5N m (increase), the right side torque correction is 5N m (decrease), according to the motor controller MCU dynamic adjustment of both sides of the steering motor 6 output.
[0041] S4: The torque sensor continuously monitors the corrected torque on both sides of the chassis walking device, if both sides of the corrected torque reach the target torque (i.e. left 45N m, right 35N m), and satisfy ΔT≤5%, then maintain the current output of both sides of the steering motor, ensure the steering torque effectively generated, make the chassis walking device gradually return to the preset route; otherwise repeat S1~S3 until both sides of the target torque is reached.
[0042] S5: The navigation module continuously detects the position of the chassis walking device, if the chassis walking device gradually returns to the preset path (such as has been from the right 8cm to the right 2cm), then gradually reduce the target torque difference on both sides, until the chassis walking device is completely returned to the straight line reference.
[0043] Example 2 The core contradiction of straight line walking control is that uneven road surface (such as potholes, slope) will cause uneven force on each wheel train 11 or abnormal posture of the chassis walking device body (such as tilt), the load difference of each steering motor 6, and then the imbalance of the output torque of the motor on both sides, causing the chassis walking device to deviate.
[0044] The straight line walking control mode includes the following steps: S1: Real-time acquisition of the actual torque of the corresponding wheel train 11 through the torque sensor; S2: Set the same target torque on both sides of the chassis walking device according to the weight of the chassis walking device and the preset speed, compare the actual torque with the target torque, and determine the deviation direction; S3: Calculate the torque correction, the motor controller MCU dynamically adjusts the output of both sides of the steering motor 6 according to the torque correction, wherein the torque correction is the difference between the actual torque and the target torque; S4: Continuously monitor the corrected torque on both sides of the chassis walking device through the torque sensor, if both sides of the corrected torque reach the target torque ±1N m, and satisfy ΔT≤5%, then maintain the current output of both sides of the steering motor 6; otherwise repeat S1~S3 until both sides of the target torque is reached.
[0045] The chassis walking device case analysis in this embodiment is as follows: The actual torque of the two left wheel systems 11 is 30N m, the load of the left steering motor 6 is reduced, the actual output torque is lower than the target torque, the left wheel speed is too fast, and the chassis walking device deviates to the right side; The actual torque of the two right wheel systems 11 is 45N m, the load of the right steering motor 6 is increased, the actual output torque is higher than the target torque, the right wheel speed is slow, and the chassis walking device deviates to the right side.
[0046] The motor torque feedback module realizes straight direction keeping through “balancing the torque on both sides”, and the process is as follows: S1: The torque sensor collects the actual torque of the left wheel system 11 of the chassis walking device as 30N m, and the actual torque of the right wheel system 11 is 45N m.
[0047] S2: The same target torque of 38N m is set on both sides of the chassis walking device, and the actual torque is compared with the target torque. Since the wheel speed on the side with low torque is fast, the chassis walking device deviates to the side with high torque, and it is judged that the chassis walking device deviates to the right side.
[0048] S3: The torque correction amount is calculated according to the principle of “suppressing fast wheels and compensating slow wheels”: The actual output torque on the right side is 7N m higher than the target torque, the output torque of the right steering motor 6 is reduced from 45N m to 38N m to avoid further slowing down of the speed; The actual output torque on the left side is 8N m lower than the target torque, the output torque of the left steering motor 6 is increased from 30N m to 38N m to suppress the trend of too fast speed.
[0049] The torque correction amount on the left side is 7N m (reduced), and the torque correction amount on the right side is 8N m (increased), and the motor controller MCU dynamically adjusts the output of the steering motor 6 on both sides accordingly.
[0050] S4: The torque sensor continuously monitors the corrected torque on both sides of the chassis walking device. If the corrected torque on both sides reaches the target torque, that is, both sides are stabilized at 38±1N m, and satisfies ΔT≤5%, it is considered that the two sides torque is approaching consistent, maintain the current two sides steering motor 6 output; If there is still deviation (such as left torque again to 35N m), otherwise repeat S1-S3, until the two sides target torque, chassis walking device returns to straight line driving.
[0051] According to the above embodiment, the role of the motor torque feedback module, the essence is to provide dynamic adjustment basis for straight line walking and steering: when straight line walking, it is a "balancer" - by eliminating the difference between the two sides torque, against the road disturbance, maintain straight; Steering, it is an "actuator" - according to the navigation requirements to make controllable torque difference, actively pull the chassis walking device back to the preset path. The whole process through the "perception - decision - adjustment - verification" closed loop, realize "path not deviation, straight stable" goal, provide guarantee for precision navigation walking.
[0052] The above only is the preferred embodiment of the present application, not by this limit the scope of the present application. It should be noted that, for ordinary technicians in this field, without departing from the technical principles of the present application, can also make a number of improvements and modifications, these improvements and modifications should be covered within the scope of the present application.
Claims
1. An agricultural chassis walking device based on wheel system contouring and torque feedback, characterized in that, It includes a walking module (1), a frame (2), and a control box (3) mounted on the frame (2); the control box (3) contains a navigation module and a URCU controller; The walking module (1) includes a wheel system (11), wheel forks (12), guide columns (13) and walking columns (14). The walking column (14) is fixed on the frame (2). A spline shaft (5) is provided inside the walking column (14). A steering motor (6) for controlling the rotation of the spline shaft (5) is installed on the walking column (14). The upper part of the spline shaft (5) is connected to the steering motor (6) through a steering transmission shaft (7). The lower part of the spline shaft (5) is located in the guide column (13) that can move up and down along the spline shaft (5). The other end of the guide column (13) is fixed on the wheel fork (12). The two sides of the wheel fork (12) are fixed to the two sides of the wheel system (11) through wheel axles (15). A distance is left between the bottom of the walking column (14) and the wheel fork (12) for the wheel system to rise as required for contouring. The walking column (14) is fitted with a compression spring (9), one end of which is limited to the guide column (13), and the other end is limited to the top of the walking column (14); A torque sensor is provided on the axle (15), and a motor controller MCU is provided on the steering motor (6). Both the motor controller MCU and the torque sensor are connected to the URCU controller.
2. The agricultural chassis walking device based on wheel system contouring and torque feedback according to claim 1, characterized in that, The steering motor (6) is mounted on the walking column (14) via the steering motor mounting base (30), and the steering drive shaft (7) is nested inside the steering motor mounting base (30); the outer ring of the steering drive shaft (7) is provided with a protrusion (25), and the steering motor mounting base (30) is provided with a groove for the rotation of the protrusion (25), and the inner wall of the groove is provided with an angle limiting strip (26) that cooperates with the protrusion (25).
3. The agricultural chassis walking device based on wheel system contouring and torque feedback according to claim 1, characterized in that, A second bearing (18) is installed on the spline shaft (5) near the top of the walking column (14); a pair of first bearings (8) installed on the guide column (13) are provided at the bottom inside the walking column (14). The pair of first bearings (8) are separated by bushings (21), and bearing sleeves (10) are provided on the first bearings (8) and the bushings (21).
4. The agricultural chassis walking device based on wheel system contouring and torque feedback according to claim 3, characterized in that, The bearing sleeve (10) is equipped with a graphene brass sleeve (16) at the position of the pair of first bearings (8). The graphene brass sleeve (16) is provided with a steel sleeve (17) for isolating from the inner wall of the walking column (14). The steel sleeve (17) is fixed to the bottom of the walking column (14).
5. The agricultural chassis walking device based on wheel system contouring and torque feedback according to claim 4, characterized in that, The inner walls of the bearing sleeve (10), the graphene brass sleeve (16) and the steel sleeve (17) are all provided with guide grooves (20) for the flow of lubricant, and the surface of the walking column (14) is provided with an oil nozzle (28) that communicates with the guide grooves (20).
6. The agricultural chassis walking device based on wheel system contouring and torque feedback according to claim 1, characterized in that, The wheel system (11) is provided with a collision protection bracket (19) around its outer circumference. The collision protection bracket (19) is fixed on the wheel axle (15). The collision protection bracket (19) is provided with a collision protection strip that is communicatively connected to the control box (3). The collision protection strip includes a front collision protection strip (33), a rear collision protection strip (34), a left collision protection strip (35), and a right collision protection strip (36).
7. The agricultural chassis walking control method based on wheel system contouring and torque feedback according to claim 1, characterized in that, This is achieved through the navigation module, wheel system anti-collision module, motor torque feedback module, and URCU controller. The wheel system anti-collision module includes the anti-collision strip, and the motor torque feedback module includes the torque sensor and the motor controller MCU. The torque sensor is used to collect the actual torque of the wheel system (11) in real time, and the motor controller MCU is used to regulate the output torque and speed of the motor. The estimated actual torque can be obtained through the back-calculation algorithm of the electrical parameters of the steering motor (6). The sampling frequency of the motor torque feedback module reaches the millisecond level, and the error ΔT between the actual torque collected by the torque sensor and the estimated actual torque at the same time is ≤5%. When there are no large obstacles on the travel route, the navigation module detects the position of the chassis travel device in real time. If it detects that the chassis travel device deviates from the navigation path or receives a steering travel command from the URCU controller, it activates the steering travel control mode until the chassis travel device is completely straightened and returns to the straight travel reference. If the wheel system or vehicle body posture of the travel device is abnormal due to changes in the road conditions on one side, it activates the straight travel control mode to balance the torque on both sides of the chassis travel device. When there are large obstacles in the walking route, the wheel system collision avoidance module triggers the wheel system collision avoidance control mode.
8. The control method for an agricultural chassis walking device based on wheel system contouring and torque feedback according to claim 7, characterized in that, The steering and driving control mode includes the following steps: S1: The actual torque of the corresponding gear train (11) is collected in real time by the torque sensor; S2: Based on the required steering curvature, direction and amplitude planned by the navigation module, set different target torques on both sides of the chassis running device to form a target torque difference between the two sides; S3: Calculate the torque correction amount. The motor controller MCU dynamically adjusts the output of the steering motors (6) on both sides according to the torque correction amount, wherein the torque correction amount is the difference between the actual torque and the target torque. S4: The torque sensor continuously monitors the corrected torque on both sides of the chassis travel device. If the corrected torque on both sides reaches the target torque and ΔT≤5%, the current output of the steering motor (6) on both sides is maintained; otherwise, S1~S3 are repeated until the target torque on both sides is reached. S5: The navigation module continuously detects the position of the chassis travel device. If the chassis travel device gradually returns to the preset path, the target torque difference between the two sides is gradually reduced until the chassis travel device is completely upright. If the chassis travel device has been completely upright, the same target torque is maintained on both sides, and the straight line reference for travel is returned.
9. The control method for an agricultural chassis walking device based on wheel system contouring and torque feedback according to claim 7, characterized in that, The straight-line walking control mode includes the following steps: S1: The actual torque of the corresponding gear train (11) is collected in real time by the torque sensor; S2: Based on the weight of the chassis running device and the preset speed, set the same target torque on both sides of the chassis running device, compare the actual torque with the target torque, and determine the direction of deviation; S3: Calculate the torque correction amount. The motor controller MCU dynamically adjusts the output of the steering motors (6) on both sides according to the torque correction amount, wherein the torque correction amount is the difference between the actual torque and the target torque. S4: Continuously monitor the corrected torque on both sides of the chassis running gear using the torque sensor. If the corrected torque on both sides reaches the target torque ±1N... If m, and ΔT≤5%, then maintain the output of the steering motors (6) on both sides; otherwise, repeat S1~S3 until the target torque on both sides is reached.
10. The control method for an agricultural chassis walking device based on wheel system contouring and torque feedback according to claim 7, characterized in that, The wheel system collision avoidance control mode is as follows: When the wheel system (11) moves forward, after the front anti-collision strip (33) comes into contact with an obstacle, the URCU controller sends a command to the wheel system (11) to stop or move backward. When the wheel system (11) moves backward, after the rear anti-collision strip (34) comes into contact with an obstacle, the URCU controller sends a command to the wheel system (11) to stop or move forward. When the wheel system (11) turns to the left, after either the left anti-collision strip (35) or the front anti-collision strip (33) comes into contact with an obstacle, the URCU controller sends a command to the wheel system (11) to stop or turn to the right to avoid it. When the wheel system (11) turns to the right, if either the right bumper (36) or the front bumper (33) comes into contact with an obstacle, the URCU controller sends a command to the wheel system (11) to stop or turn to the left to avoid it.