Foot-ground interaction experiment platform and topographic feature online characterization method

Abstract

The invention discloses a foot-ground interaction experiment platform and a topographic feature online characterization method, and relates to the technical field of robot foot-ground interaction. An experiment table structural member comprises an experiment table base, a containing groove and an experiment table frame, and the containing groove and the experiment table frame are installed on the experiment table base; the sliding table mechanism is mounted on the experiment table rack; the pressing mechanism is movably connected with the sliding table mechanism; the foot end module is mounted at the moving tail end of the pressing mechanism and is used for being in contact with the ground sample in the accommodating groove; the force sensor is installed at the bottom of the foot end module or the joint of the pressing mechanism and the foot end module and used for collecting foot end normal force and foot end tangential force. And the data processing system is used for receiving the acquired foot end normal force and the foot end tangential force and processing the foot end normal force and the foot end tangential force to obtain topographic features. According to the invention, the contact between the foot end of the robot and the ground can be truly simulated, a contact experiment between the foot end and different grounds can be carried out in an indoor environment, and topographic features can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of robot foot-ground interaction, and more particularly to a foot-ground interaction experimental platform and an online representation method for terrain features. Background Art

[0002] The foot is the only carrier for the interaction between the robot and the terrain environment, and the foot-ground force is also the only external main force for the robot. Therefore, the robot's mobility is also mainly determined by the foot-ground force, which is particularly important in the application of legged robots. The operating environment of legged robots is more severe than that of ordinary robots, and they are often used in emergency rescue, environmental survey and other fields. When the environment is unknown and the planned path is long, especially in rugged and complex terrain, it is necessary to reasonably control the robot's foot force to prevent the foot from slipping and sinking during movement, thereby avoiding damage to the robot's driving parts and imbalance and overturning of the robot body.

[0003] The foot-ground interaction force has a direct impact on the robot's stability, the reasonable distribution of foot-end force, and the parameter selection of the torque control scheme. The foot-ground interaction force directly affects the robot's foot-end force distribution, force-torque control strategy, etc., and further has a direct impact on the robot's performance. Based on the foot-ground interaction model, the robot can realize terrain classification and recognition, accurately obtain the physical characteristics of the terrain, and adjust its own movement strategy in time, effectively improving the robot's carrying and passing capabilities.

[0004] In recent years, the widespread application of legged robots has promoted the research demand for foot-ground contact models, which is not limited to the control of the spatial displacement of the foot end, but more pursues the real simulation of the foot-ground contact. For example, the Chinese patent with the announcement number CN117268735A can control the longitudinal and lateral displacement of the foot end, but only controls the movement of the entire foot, and lacks the control of the angle of the foot end invading the ground; the Chinese patent with the announcement number CN215338942U discloses a system that can test the dynamic performance of the foot-ground interaction of a legged robot. The invention can change the foot end contact angle, but the control of the longitudinal position of the foot end requires the replacement of the counterweight block, which affects the continuity of the experiment. Summary of the invention

[0005] In view of this, an object of the present invention is to provide an experimental platform and method that can control the contact position between the foot end and the ground, the intrusion conditions, and can obtain ground-related information in real time online.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A foot-ground interaction experimental platform, comprising an experimental platform structure, a sliding platform mechanism, a pressing mechanism, a foot end module, a force sensor, and a data processing system;

[0008] The experimental bench structure comprises an experimental bench base, a receiving groove and an experimental bench frame installed on the experimental bench base; the sliding mechanism is installed on the experimental bench frame; the pressing mechanism is movably connected with the sliding mechanism and is located above the opening side of the receiving groove; the foot end module is installed at the moving end of the pressing mechanism to contact the ground sample in the receiving groove;

[0009] The force sensor is installed at the bottom of the foot end module or at the connection between the downward pressure mechanism and the foot end module, and is used to collect the foot end normal force and the foot end tangential force; the data processing system is used to receive the foot end normal force and the foot end tangential force collected by the force sensor, and obtain the terrain characteristics after processing.

[0010] Furthermore, the slide mechanism drives the pressing mechanism to move along the length direction of the accommodating groove; the pressing mechanism drives the foot end module and the force sensor to move along the vertical direction.

[0011] Furthermore, the slide mechanism includes a first drive motor, a first connecting plate, a first lead screw module, a first coupling, a drag chain, a module cover, a slider and a transfer platform;

[0012] The module cover is installed on the experimental bench, and a first screw module is accommodated inside; the first drive motor is fixed to one side of the module cover through a first connecting plate, and the output shaft of the first drive motor is connected to the first screw module through the first coupling; the slider cooperates with the first screw module; the adapter is connected to the slider, and is located on a side of the module cover close to the downward pressure mechanism, and is used to support the downward pressure mechanism; the drag chain is installed on a side of the module cover away from the downward pressure mechanism, and is used to place the wiring harness.

[0013] Furthermore, the pressing mechanism is installed on the transfer platform, and includes a second drive motor, a second coupling, a second lead screw module, a guide rod, and a second connecting plate;

[0014] The output shaft of the second drive motor is connected to the second screw module through the second coupling; the guide rod passes through the adapter, one end of which is connected to the second screw module, and the output end is connected to the second connecting plate.

[0015] Further, the foot-end module includes a foot-end member and a foot-end adapter block;

[0016] One end of the foot end adapter block is connected to the second connecting plate, and the other end is connected to the foot end member, and the foot end member is used to contact the ground sample in the containing groove.

[0017] Furthermore, the force sensor includes a six-dimensional force sensor and / or a bionic tactile sensor; the six-dimensional force sensor is installed at the connection between the foot end adapter block and the second connecting plate; the bionic tactile sensor is installed at the sole of the foot end component.

[0018] Furthermore, the experimental bench base is also provided with a base handle, a foot and a mounting hole; the base handle is installed above the experimental bench base; the foot is installed under the four corners of the experimental bench base for leveling the entire experimental bench; the mounting holes are evenly distributed on the experimental bench base plate.

[0019] Furthermore, the data processing system includes a data acquisition module, a data processing module and a real-time characterization interface; the data acquisition module is connected to the force sensor and is used to collect sensing data, including foot-end normal force and foot-end tangential force; the data processing module is used to process the foot-end normal force and foot-end tangential force to obtain terrain characteristics; the real-time characterization interface is used to integrate and display real-time data, accumulated data, fitting curves and terrain characteristic parameters.

[0020] The present invention also provides an online terrain feature characterization method, which is implemented based on the above-mentioned foot-ground interaction experimental platform and includes the following steps:

[0021] Step 1: Place the experimental ground sample in the receiving tank, smooth the surface of the ground sample, adjust the slide mechanism and the pressing mechanism so that the foot end module is located above the opening of the receiving tank; install the force sensor and connect it to the data processing system;

[0022] Step 2: Control the slide mechanism and the pressing mechanism to press the foot end member into the ground sample; after the foot end member is pressed into a preset depth, control the slide mechanism and the pressing mechanism to pull the foot end member out of the ground sample; during the experiment, the normal force and the tangential force of the foot end are collected in real time through the force sensor;

[0023] Step three: processing the foot end normal force and the foot end tangential force to obtain terrain features.

[0024] Furthermore, in step three, a foot-ground force model is established, and terrain characteristics are obtained according to the foot end normal force and the foot end tangential force; the foot-ground force model includes a normal bearing model and a tangential shear model;

[0025] Normal pressure model:

[0026] F N = kδ n ;

[0027] In the formula, F N - normal force on the foot end; δ-foot terrain variable; k-foot equivalent hardness coefficient; n-deformation index coefficient;

[0028] Tangential shear model:

[0029] F T =-th(j,1.5K)μF N ;

[0030] In the formula, F T -The foot end is subjected to tangential force; μ-ground friction coefficient; j-ground tangential deformation; K-ground shear deformation modulus;

[0031]

[0032] It can be seen from the above technical solutions that the present invention provides a foot-ground interaction experimental platform and an online characterization method for terrain features, which have the following beneficial effects compared with the prior art:

[0033] (1) In the experimental platform of the present invention, the movement of the slide mechanism and the downward pressure mechanism is controlled to make the foot end penetrate the ground in different ways, simulating the contact between the robot foot end and the ground. The present invention can also adjust the angle of the foot end penetrating the ground by replacing the foot end adapter block, further restoring the contact between the robot foot end and the ground during movement.

[0034] (2) In the present invention, since the experimental platform base is not surrounded by any surroundings and regularly arranged mounting holes are pre-processed, the platform can accommodate and fix various types of ground samples, thereby enabling foot-ground interaction and online characterization of terrain features for different types of ground samples.

[0035] (3) The present invention can install a six-dimensional force sensor above the foot end and a bionic tactile sensor below the foot end, which can support simulation of robot foot ends of different design types.

[0036] (4) The present invention combines the terrain online characterization method and the real-time data acquisition system to collect and process the experimental process data in real time, and intuitively display the data such as the foot end force and terrain characteristic parameters through the host computer interface, providing the experimenters with the convenience of real-time feedback and data analysis.

[0037] In summary, the present invention can realistically simulate the contact between the robot's foot and the ground, simulate the movement of the robot in different terrain environments, conduct contact experiments between the foot and different ground surfaces in an indoor environment, and perform online characterization of terrain features. The experimental platform and method of the present invention are highly flexible, easy to operate and expand, and provide strong support for the research and development of robot foot-ground interaction, with high practical value and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0039] Figure 1 It is a three-dimensional structural diagram of a foot-ground interactive experimental platform of the present invention;

[0040] Figure 2 It is a front view of a foot-ground interaction experimental platform of the present invention;

[0041] Figure 3 It is a side view of a foot-ground interaction experimental platform of the present invention;

[0042] Figure 4 is a side view of the foot end module of the present invention;

[0043] Figure 5 is a front view of the foot end module of the present invention;

[0044] Among them, 100 represents the experimental bench structure; 200 represents the sliding mechanism; 300 represents the pressing mechanism; 400 represents the foot-end module; 101 represents the experimental bench base; 102 represents the base handle; 103 represents the receiving slot; 104 represents the experimental bench frame; 201 represents the first driving motor; 202 represents the first connecting plate; 203 represents the sliding module cover; 204 represents the drag chain; 205 represents the adapter table; 301 represents the second driving motor; 302 represents the second coupling; 303 represents the second screw module; 304 represents the guide rod; 305 represents the second connecting plate; 401 represents the sensor adapter plate; 402 represents the six-dimensional force sensor; 403 represents the foot-end adapter block; 404 represents the foot-end component; 405 represents the bionic tactile sensor. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not 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.

[0046] The embodiment of the present invention discloses a foot-ground interaction experimental platform, see Figure 1-Figure 2, including a test bench structure 100, a slide mechanism 200, a pressing mechanism 300, a foot end module 400, a force sensor, and a data processing system; the test bench structure 100 includes a test bench base 101 and a receiving groove 103 and a test bench frame 104 installed on the test bench base 101; the slide mechanism 200 is installed on the test bench frame 104; the pressing mechanism 300 is movably connected with the slide mechanism 200 in the vertical direction and is located above the opening side of the receiving groove 103; the foot end module 400 is installed at the moving end of the pressing mechanism 300, and is used to contact the ground sample in the receiving groove 103; the force sensor is installed at the bottom of the foot end module 400 or at the connection between the pressing mechanism 300 and the foot end module 400, and is used to collect the foot end normal force and the foot end tangential force; the data processing system is used to receive the foot end normal force and the foot end tangential force collected by the force sensor, obtain the terrain characteristics after processing, and display them in real time on the upper computer screen.

[0047] The non-structural ground can be simulated by the receiving groove 103, and the slide mechanism 200 drives the pressing mechanism 300 to move along the length direction of the receiving groove 103; the pressing mechanism 300 drives the foot end module 400 and the force sensor to move along the vertical direction, so that the foot end module 400 can be pressed into the above-mentioned ground sample and then lifted. When the foot end contacts the simulated ground in the receiving groove 103, the force sensor obtains data, which is collected and processed by the data processing system, and the experimental data and related parameters are displayed on the host computer. The foot-ground experimental platform can achieve different conditions of soil invasion by controlling the spatial position of the foot end, and can truly simulate the contact between the robot foot end and the ground.

[0048] The slide mechanism 200 includes a first drive motor 201, a first connecting plate 202, a first screw module, a first coupling, a drag chain 204, a module cover 203, a slider and a transfer table 205; the module cover 203 is installed on the experimental bench 104, and the first screw module is accommodated inside; the first drive motor 201 is fixed to one side of the module cover 203 through the first connecting plate 202, and the output shaft of the first drive motor 201 is connected to the first screw module through the first coupling; the slider cooperates with the first screw module; the transfer table 205 is connected to the slider, located on the side of the module cover 203 close to the pressing mechanism 300, and is used to support the pressing mechanism 300; the drag chain 204 is installed on the side of the module cover 203 away from the pressing mechanism 300, and is used to place the wiring harness. The transfer table 205 can reciprocate along the length direction of the slide mechanism 200 through the first drive motor 201. In a specific implementation process, the first driving motor 201 may be a servo motor.

[0049] The pressing mechanism 300 is installed on the transfer platform 205, see Figure 3, including a second drive motor 301, a second coupling 302, a second lead screw module 303, a guide rod 304, and a second connecting plate 305; the output shaft of the second drive motor 301 is connected to the second lead screw module 303 through the second coupling 302; the guide rod 304 passes through the transfer table 205, one end is connected to the second lead screw module 303, and the output end is connected to the second connecting plate 305. The initial position of the pressing mechanism 300 is located at the center of the opening of the receiving groove 103. The second drive motor 301 can be a servo motor, which is driven by the second lead screw module 303 to achieve position, speed and force control in the vertical direction.

[0050] The first drive motor 201 and the second drive motor 301 are both controlled by an STM32F407 control board, which communicates with the motor driver and sends control signals to change the motor motion state.

[0051] The foot end module 400 includes a foot end member 404 and a foot end adapter block 403, see Figure 4-Figure 5 One end of the foot end adapter block 403 is connected to the second connecting plate 305, and the other end is connected to the foot end member 404. The foot end member 404 is used to contact the ground sample in the receiving groove 103. By changing the insertion position of the positioning pin, the foot end member 404 can penetrate the ground sample at different angles to truly simulate the contact between the legs and the ground during the movement of the robot. It should be noted that the foot end member 404 can be a conventional round flat-bottomed foot, a spherical foot, a bionic foot, etc.

[0052] The force sensor includes a six-dimensional force sensor 402 and / or a bionic tactile sensor 405; the six-dimensional force sensor 402 is installed at the connection between the foot-end adapter block 403 and the second connecting plate 305. To install the six-dimensional force sensor 402, an additional sensor adapter plate 401 is required to be connected to the bottom of the second connecting plate 305. The six-dimensional force sensor 402, the foot-end adapter block 403 and the foot-end member 404 are installed in sequence below the sensor adapter plate 401; the bionic tactile sensor 405 is installed at the sole of the foot-end member 404 and contacts the ground before the foot-end member 404. The above two force sensors can be used simultaneously or separately. Compared with the traditional multi-dimensional force sensor, the bionic tactile sensor 405 effectively reduces the robot's own load, reduces the robot's volume, and enriches the types of robot feet that can be simulated by the experimental platform.

[0053] The experimental bench base 101 is also provided with a base handle 102, feet and mounting holes; the base handle 102 is installed above the experimental bench base 101; the feet are installed under the four corners of the experimental bench base 101 for leveling the entire experimental bench; the mounting holes are evenly distributed on the experimental bench base 101 board.

[0054] According to the experimental needs, the ground sample in the receiving groove 103 can be a soil sample or other ground sample to be tested. Similarly, when the ground sample to be tested is other hard ground sample, the receiving groove 103 device can be discarded, and the hard ground sample can be directly fixed on the experimental table base 101 through the mounting hole, so as to expand the types of experimental objects and obtain more comprehensive experimental data.

[0055] The data processing system includes a data acquisition module, a data processing module and a real-time characterization interface; the data acquisition module is connected to the force sensor and is used to collect sensor data, including the normal force at the foot end and the tangential force at the foot end; the data processing module is used to process the normal force at the foot end and the tangential force at the foot end to obtain terrain characteristics; the real-time characterization interface is used to integrate and display real-time data, accumulated data, fitting curves and terrain characteristic parameters to help have an intuitive understanding of the experimental ground.

[0056] Based on the above-mentioned foot-ground interaction experimental platform, another embodiment of the present invention further provides an online terrain feature characterization method, comprising the following steps:

[0057] Step 1, experimental preparation stage: load the experimental ground sample into the receiving groove 103, smooth the surface of the ground sample, adjust the slide mechanism 200 and the pressing mechanism 300 so that the foot end module 400 is located above the opening of the receiving groove 103; install the force sensor and connect it to the data processing system.

[0058] Step 2, experimental stage: control the slide mechanism 200 and the pressing mechanism 300 to press the foot end member 404 into the ground sample; after the foot end member 404 is pressed into a preset depth, reversely operate the first drive motor 201 and the second drive motor 301 to pull the foot end member 404 out of the ground sample when it sinks; during the experiment, the normal force and the tangential force of the foot end are collected in real time through the force sensor.

[0059] In order to comprehensively verify the performance of the robot foot, the experimental method can be divided into normal pressure test, tangential friction test and comprehensive trajectory test according to needs by controlling the slide mechanism 200 and the pressing mechanism 300 respectively. The normal pressure test and the comprehensive trajectory test include setting the initial position of the foot end member 404, and the foot end member 404 should maintain a certain distance from the soil surface for the start of the force sensor; the tangential friction test sets the initial position of the foot end member 404 on one side of the length direction of the soil groove, and presses it into the soil sample to a certain depth.

[0060] The normal bearing test and the comprehensive trajectory test include setting the pressing speed and the pressing depth. The pressing speed must meet the quasi-static requirements of the foot-ground force model. The pressing depth can be determined by a pre-pressing test. During the pre-pressing test, the real-time characterization interface is observed. When the force data surges, the soil trough boundary has affected the force at the foot end, and the pressing depth must not exceed this depth. At the same time, the pressing depth must be less than the length of the foot end component 404.

[0061] Step 3: Post-experimental data processing stage: processing is performed based on the foot end normal force and foot end tangential force to obtain terrain features.

[0062] Furthermore, in step three, a foot-ground force model is established, and terrain characteristics are obtained according to the foot end normal force and the foot end tangential force; the foot-ground force model includes a normal bearing model and a tangential shear model;

[0063] Normal pressure model:

[0064] F N = kδ n ;

[0065] In the formula, F N - normal force on the foot end; δ-foot terrain variable; k-foot equivalent hardness coefficient; n-deformation index coefficient;

[0066] Tangential shear model:

[0067] F T =-th(j,1.5K)μF N ;

[0068] In the formula, F T -The foot end is subjected to tangential force; μ-ground friction coefficient; j-ground tangential deformation; K-ground shear deformation modulus;

[0069]

[0070] When applied to the foot-ground interaction test bench, the F N 、F T ; δ and j can be obtained from the parameters set by the motor; then the normal pressure equation is a function of k and n, and the tangential shear equation is a function of K and μ. When the same set of experiments are conducted, the foot-end component 404 used is the same, and the only influencing factors of k, n, K, and μ are the physical properties of the terrain. After the parameters in the foot-ground force model are determined through experiments, k and n reflect the normal physical properties of the ground, and K and μ reflect the tangential physical properties of the ground, which can be used as the basis for the robot foot-end control strategy.

[0071] Before each experiment according to the above method and steps, the ground sample should be restored to a flat surface, and it should be ensured that the initial position of the foot end member 404 will not affect the subsequent experimental data.

[0072] When conducting experiments, the motor parameters can be regarded as constants after being set. The experimental data collected by the force sensor is input into the real-time characterization interface through the data processing system, and substituted into the normal pressure equation and the tangential shear equation respectively. The two equations are regressed and calculated using the linear regression algorithm in Python, and finally the normal pressure parameters: k, n, and the tangential shear parameters: K, μ are obtained. After multiple groups of experiments, the normal pressure parameters and tangential shear parameters obtained can represent the physical properties of this type of terrain. When applied to robots, after the robot's foot detects and obtains two sets of parameters, the terrain type corresponding to the two sets of parameters can be matched according to the deep learning algorithm, and the movement strategy can be adjusted according to the physical properties of the terrain.

[0073] It should be noted that Figure 1 The figure is only one embodiment of the present invention, and the foot end component 404 can be replaced with common robot feet such as round flat-bottomed feet, cylindrical feet, spherical feet and bionic feet. The foot end adapter block 403 can change the tilt angle or change the adapter block type to adjust the angle at which the foot end contacts the ground. The drive motors of the pressing mechanism 300 and the slide mechanism 200 can also change the control mode to achieve control of different physical quantities. The present invention can also perform simulation experiments on different types of robot feet by controlling and changing the above-mentioned components. In the specific experimental process, in order to protect the experimental table, a limit device can also be installed on the pressing mechanism 300 and the slide mechanism 200.

[0074] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0075] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A foot-ground interaction experimental platform, characterized in that: It includes the experimental table structure, sliding table mechanism, pressing mechanism, foot end module, force sensor and data processing system; The experimental bench structure comprises an experimental bench base, a receiving groove and an experimental bench frame installed on the experimental bench base; the sliding mechanism is installed on the experimental bench frame; the pressing mechanism is movably connected with the sliding mechanism and is located above the opening side of the receiving groove; the foot end module is installed at the moving end of the pressing mechanism to contact the ground sample in the receiving groove; The force sensor is installed at the bottom of the foot end module or at the connection between the downward pressure mechanism and the foot end module, and is used to collect the foot end normal force and the foot end tangential force; the data processing system is used to receive the foot end normal force and the foot end tangential force collected by the force sensor, and obtain the terrain characteristics after processing.

2. The foot-ground interaction experimental platform according to claim 1, characterized in that: The slide mechanism drives the pressing mechanism to move along the length direction of the accommodating groove; the pressing mechanism drives the foot end module and the force sensor to move along the vertical direction.

3. The foot-ground interaction experimental platform according to claim 1, characterized in that: The slide mechanism includes a first drive motor, a first connecting plate, a first lead screw module, a first coupling, a drag chain, a module cover, a slide block and a transfer platform; The module cover is installed on the experimental bench, and a first screw module is accommodated inside; the first drive motor is fixed to one side of the module cover through a first connecting plate, and the output shaft of the first drive motor is connected to the first screw module through the first coupling; the slider cooperates with the first screw module; the adapter is connected to the slider, and is located on a side of the module cover close to the downward pressure mechanism, and is used to support the downward pressure mechanism; the drag chain is installed on a side of the module cover away from the downward pressure mechanism, and is used to place the wiring harness.

4. The foot-ground interaction experimental platform according to claim 3, characterized in that: The pressing mechanism is installed on the transfer platform, and includes a second driving motor, a second coupling, a second lead screw module, a guide rod, and a second connecting plate; The output shaft of the second drive motor is connected to the second screw module through the second coupling; the guide rod passes through the adapter, one end of which is connected to the second screw module, and the output end is connected to the second connecting plate.

5. The foot-ground interaction experimental platform according to claim 4, characterized in that: The foot end module includes a foot end member and a foot end adapter block; One end of the foot end adapter block is connected to the second connecting plate, and the other end is connected to the foot end member, and the foot end member is used to contact the ground sample in the containing groove.

6. The foot-ground interaction experimental platform according to claim 5, characterized in that: The force sensor includes a six-dimensional force sensor and / or a bionic tactile sensor; the six-dimensional force sensor is installed at the connection between the foot end adapter block and the second connecting plate; the bionic tactile sensor is installed at the sole of the foot end component.

7. The foot-ground interaction experimental platform according to claim 1, characterized in that: The experimental bench base is also provided with a base handle, a foot and a mounting hole; the base handle is installed above the experimental bench base; the foot is installed under the four corners of the experimental bench base for leveling the entire experimental bench; the mounting holes are evenly distributed on the experimental bench base plate.

8. The foot-ground interaction experimental platform according to claim 1, characterized in that: The data processing system includes a data acquisition module, a data processing module and a real-time characterization interface; the data acquisition module is connected to the force sensor and is used to collect sensing data, including the normal force at the foot end and the tangential force at the foot end; the data processing module is used to process the normal force at the foot end and the tangential force at the foot end to obtain terrain features; The real-time characterization interface is used to integrate and display real-time data, accumulated data, fitting curves and terrain feature parameters.

9. A method for online characterization of terrain features, implemented based on a foot-ground interaction experimental platform according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Place the experimental ground sample in the receiving tank, smooth the surface of the ground sample, adjust the slide mechanism and the pressing mechanism so that the foot end module is located above the opening of the receiving tank; install the force sensor and connect it to the data processing system; Step 2: Control the slide mechanism and the pressing mechanism to press the foot end member into the ground sample; after the foot end member is pressed into a preset depth, control the slide mechanism and the pressing mechanism to pull the foot end member out of the ground sample; during the experiment, the normal force and the tangential force of the foot end are collected in real time through the force sensor; Step three: processing the foot end normal force and the foot end tangential force to obtain terrain features.

10. The method for online characterization of terrain features according to claim 9, characterized in that: In step three, a foot-ground force model is established, and terrain characteristics are obtained according to the foot end normal force and the foot end tangential force; the foot-ground force model includes a normal bearing model and a tangential shear model; Normal pressure model: F N =kδ n ; In the formula, F N - normal force on the foot end; δ-foot terrain variable; k-foot equivalent hardness coefficient; n-deformation index coefficient; Tangential shear model: F T =-th(j,1.5K)μF N ; In the formula, F T -The foot end is subjected to tangential force; μ-ground friction coefficient; j-ground tangential deformation; K-ground shear deformation modulus;

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