Joint protection method of wheel-leg composite robot and wheel-leg composite robot

Abstract

The invention discloses a joint protection method of a wheel-leg composite robot and the wheel-leg composite robot, belongs to the technical field of robots, and aims to solve one of the problems that the anti-falling capability of a wheel-leg robot is poor, joints are easy to damage, and the motion capability and efficiency of the robot in a complex environment are reduced by an existing robot joint protection method and device. The joint protection method comprises the steps that when a robot executes a task, a control system starts a joint protection mechanism opening and closing strategy; the control system sends an action instruction to the joint protection mechanism according to the joint protection mechanism opening and closing strategy; the joint protection mechanism executes the action instruction; if the unfolding instruction is executed, physical protection is carried out on hip joints of the robot; and executing the retraction instruction to expose the hip joint of the robot to the outside. Dynamic protection of the robot joints is achieved, and the damage risk caused by collision, overload or posture instability of the hip joints is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of robotics, specifically to a joint protection method for a wheel-leg hybrid robot and the wheel-leg hybrid robot itself. Background Technology

[0002] Joint motors are the core of the "muscle-skeletal" structure of wheeled-legged hybrid robots. They are the sole actuators for gait generation, dynamic balance, and obstacle-crossing movements, and directly determine the overall power density, energy efficiency limit, and reliability of the robot. They are not only crucial but also expensive; frequent replacements or repairs can significantly impact product reliability and cost. Because wheeled-legged hybrid robots need to operate in various scenarios, both indoors and outdoors, especially at high speeds, they are highly susceptible to risks such as collisions, falls, or being struck by heavy objects. This makes joint motors the most vulnerable components, particularly the hip joint, which, due to its unique position and function, is highly susceptible to damage with serious consequences.

[0003] Currently, the protection of the hip joint of wheel-leg hybrid robots mainly relies on adding flexible protective pads or frames, or setting up special protective structures between the body and the hip joint. However, all of these methods significantly increase the overall size and weight of the quadruped robot, making the robot's structure more complex. Furthermore, they cannot be controlled in real time and are inconvenient to disassemble, thereby greatly reducing the robot's ability to move and its flexibility in complex environments. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a joint protection method for a wheel-legged hybrid robot and a wheel-legged hybrid robot, in order to solve one of the problems of wheel-legged robots being prone to falling and damaging joint motors, and existing robot joint protection methods and devices reducing the robot's mobility and efficiency in complex environments.

[0005] The objective of this invention is mainly achieved through the following technical solutions.

[0006] In a first aspect, the present invention provides a joint protection method for a wheel-legged composite robot, comprising the following steps:

[0007] When the S100 robot performs a task, the control system activates the joint protection mechanism's opening and closing strategy.

[0008] The S200 control system sends action commands to the joint protection mechanism according to the opening and closing strategy of the joint protection mechanism.

[0009] The S300 joint protection mechanism executes action commands; when executing the unfold command, it provides physical protection for the robot's hip joint; when executing the retract command, it exposes the robot's hip joint to the outside.

[0010] Furthermore, the joint protection mechanism opening and closing strategies in S100 include, in descending order of priority, a first-level control strategy, a second-level control strategy, and a third-level control strategy.

[0011] Furthermore, the first-level control strategy is a passive control strategy, in which the control system sends action commands to the joint protection mechanism according to explicit passive control instructions.

[0012] Furthermore, the second-layer control strategy is an active control strategy, which is a predictive risk decision based on multi-sensor data fusion.

[0013] Furthermore, the third-layer control strategy is a real-time adjustment strategy, which dynamically fine-tunes the system based on data feedback from sensors.

[0014] Furthermore, S200 also includes the following steps:

[0015] The S210 control system executes the first-level control strategy and checks for explicit passive control commands; if so, it generates a passive control layer decision d. passive If ∈{0,1}, proceed to S240; otherwise, proceed to S220.

[0016] The S220 control system executes the second-level control strategy and calculates the active control layer decision D. active ∈{0,1};

[0017] The S230 control system executes a third-level control strategy, making real-time adjustments based on sensor data and calculating the real-time adjustment amount D. realtime ;

[0018] The S240 control system will make decisions at the passive control layer. passive ∈{0,1}, Active control layer decision D active ∈{0,1} and real-time adjustment D realtime Perform fusion calculations to obtain the final action command D. final ∈{0,1}.

[0019] Furthermore, the S100 also includes a high-speed driving stability control strategy when the robot performs a high-speed driving task.

[0020] Furthermore, in S220, the second-level control strategy includes the following decision-making steps:

[0021] The S221 sensor collects and feeds back environmental or status information variables to the control system in real time.

[0022] The S222 control system calculates the risk factor for each risk submodule based on the information variables fed back from the sensors.

[0023] The S223 control system performs weighted risk calculation and threshold judgment based on risk factors to arrive at the active control layer decision D. active ∈{0,1}.

[0024] Furthermore, the risk submodule includes a falling object risk submodule, a fall risk submodule, and a narrow path suppression module; the narrow path suppression module outputs a narrow path suppression factor I. narrow This prevents the joint protection mechanism from deploying when the robot is in a sufficiently narrow path.

[0025] Furthermore, the high-speed driving stability control strategy in S100 includes: the control system dynamically calculates and adjusts the heading angle of each foot wheel in real time; the heading angle includes the toe angle δ and the camber angle γ.

[0026] Furthermore, the high-speed driving stability control strategy in S100 also includes: when the robot is in a high-speed straight-line cruise state, assigning each foot wheel toe angle δ to zero or a small positive toe angle δ1; when the robot is making a high-speed turn, assigning differentiated toe angles δ to the inner and outer wheels; when the robot body yaws excessively, independently adjusting the toe angle δ of the foot wheel on the yaw direction side; and when the robot needs to brake urgently, assigning a small positive toe angle δ1 to all foot wheels.

[0027] Furthermore, the high-speed driving stability control strategy in S100 also includes: when the road surface is uneven or the robot tilts, applying a negative camber angle γ2 to the foot wheel on the lower side and a positive camber angle γ1 to the foot wheel on the higher side.

[0028] In a second aspect, the present invention provides a wheel-leg composite robot, which is protected by the joint protection method of the wheel-leg composite robot of the first aspect of the present invention. The wheel-leg composite robot includes a body, a joint protection mechanism and a control system.

[0029] Furthermore, the joint protection mechanism includes protective components, drive components, and locking components.

[0030] Furthermore, the protective components include a protective shield, a drive mechanism that can drive the protective shield to extend or retract outside the robot's hip joint, and a locking mechanism that can lock the protective shield in the retracted position.

[0031] Furthermore, it also includes a wheel-leg actuator, which comprises six joints and five degrees of freedom.

[0032] Furthermore, the wheel-leg actuator includes a lateral swing joint and a foot rotation joint. The lateral swing joint can adjust the toe angle δ of the foot wheel; the foot rotation joint can adjust the camber angle γ of the foot wheel.

[0033] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0034] 1. The joint protection method of the wheel-leg composite robot of the present invention, by setting the opening and closing strategy of the joint protection mechanism, can deploy the joint protection mechanism in a timely manner when necessary, provide physical protection for the joint motor, effectively avoid damage caused by external impact or foreign object entry, improve the service life of joint components and system reliability, and reduce costs; when not necessary, the protection mechanism is retracted to restore the robot's optimal motion performance and maintain the robot's motion flexibility and energy efficiency.

[0035] 2. The joint protection method for the wheel-leg hybrid robot of the present invention includes a three-layer control strategy in the joint protection mechanism opening and closing strategy in step S200, namely a passive control strategy, an active control strategy, and a real-time adjustment strategy. This strategy can combine the complex environment and the robot's own motion posture to comprehensively decide the action commands for the joint protection mechanism, enabling the joint protection mechanism to dynamically and adaptively protect the robot's hip joint during movement in complex terrain, effectively reducing the risk of hip joint damage caused by collision, overload, or posture instability.

[0036] 3. The joint protection method of the wheel-leg composite robot of the present invention outputs active control layer decision through the fusion judgment mechanism of multiple risk factors in S220, realizing the collaborative assessment of multiple risks such as falling objects, falls and narrow paths in complex working environments; by dynamically adjusting the weight allocation of each risk factor, the balance between motion efficiency and joint protection is taken into account.

[0037] 4. The joint protection method of the wheel-leg composite robot of the present invention, by activating a high-speed driving stability control strategy when performing a high-speed driving task in S100, can dynamically calculate and adjust the heading angle of the foot wheel, and through the fusion control of the toe angle δ and the camber angle γ, enable the wheel-leg robot to improve anti-slip, anti-yaw and pitch stability during high-speed movement, high-speed cornering and dealing with uneven road surfaces, and can simultaneously enhance road holding ability, lateral stability and safety, thereby improving the stability of the robot during high-speed driving and reducing the risk of robot falls and joint damage.

[0038] 5. The wheel-leg hybrid robot of the present invention, by setting a joint protection mechanism with a three-dimensional parallelogram structure, can not only enable the joint protection mechanism to execute the action commands of the control system agilely and stably, but also maintain the robot's motion performance while maximizing space utilization. In addition, the joint protection mechanism is lightweight, convenient for quick installation and disassembly, and improves the flexibility of robot use.

[0039] 6. The wheel-leg composite robot of the present invention, by setting a wheel-leg actuator with six joints and five degrees of freedom, can flexibly adjust the toe angle δ and camber angle γ of the foot wheel, realize real-time control of the driving posture, improve the stability of the robot at high speed, and reduce the risk of robot falling and joint damage.

[0040] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the overall steps of the joint protection method for the wheel-leg hybrid robot according to an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of step S200 of the joint protection method according to Embodiment 1 of the present invention;

[0043] Figure 3 This is a schematic diagram of the toe angle structure of the joint protection method in Embodiment 2 of the present invention;

[0044] Figure 4 This is a schematic diagram of the outward tilt angle of the joint protection method according to Embodiment 2 of the present invention;

[0045] Figure 5 This is a schematic diagram of the overall structure of the wheel-leg hybrid robot of Embodiment 3 of the present invention;

[0046] Figure 6 This is a schematic diagram of the joint protection mechanism of Embodiment 3 of the present invention;

[0047] Figure 7 This is a schematic diagram of the joint protection mechanism of Embodiment 3 of the present invention in its deployed state;

[0048] Figure 8 This is a schematic diagram of the joint protection mechanism in the retracted state according to Embodiment 3 of the present invention;

[0049] Figure 9 This is a schematic diagram of the wheel-leg actuator of Embodiment 3 of the present invention.

[0050] Figure label:

[0051] 1-Fuselage;

[0052] 2-Joint protection mechanism;

[0053] 21-Protective component; 211-Protective cover; 212-First push rod; 213-Second push rod; 214-Mounting plate;

[0054] 22-Drive components;

[0055] 23-Locking component;

[0056] 3-Wheel-leg actuator;

[0057] 31-Joint; 311-Lateral swing joint; 312-Forward swing joint; 313-Knee joint; 314-Ankle joint;

[0058] 315 - Foot rotation joint; 316 - Foot wheel rotation joint; 317 - Telescopic joint motor;

[0059] 32- Thigh;

[0060] 33-lower leg;

[0061] 34-Wheel foot; 341-Foot end wheel;

[0062] δ - Anterior head angle; δ1 - Positive anterior head angle; δ2 - Negative anterior head angle;

[0063] γ - outward inclination; γ1 - positive outward inclination; γ2 - negative outward inclination. Detailed Implementation

[0064] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0065] Example 1

[0066] This embodiment provides a joint protection method for a wheel-legged hybrid robot. The wheel-legged hybrid robot includes an openable joint protection mechanism, an opening and closing strategy for the joint protection mechanism, and a control system. Figure 1 As shown, the joint protection method includes the following steps:

[0067] When the S100 robot performs a task, the control system activates the joint protection mechanism's opening and closing strategy.

[0068] The S200 control system sends action commands to the joint protection mechanism according to the opening and closing strategy of the joint protection mechanism.

[0069] The S300 joint protection mechanism executes action commands; when executing the unfold command, it provides physical protection for the robot's hip joint; when executing the retract command, it exposes the robot's hip joint to the outside.

[0070] The joint protection method of the wheel-leg hybrid robot in this embodiment, by setting the opening and closing strategy of the joint protection mechanism, can deploy the joint protection mechanism in a timely manner when necessary, providing physical protection for the joint motor, effectively reducing damage caused by external impact or foreign object intrusion, improving the service life of joint components and system reliability, and reducing costs; when not necessary, the protection mechanism can be retracted to restore the robot's optimal motion performance, improve the robot's motion flexibility and energy efficiency.

[0071] Furthermore, considering that the robot needs to possess both passive and active protection capabilities, the joint protection mechanism opening and closing strategy in S100 includes a first-level control strategy, a second-level control strategy, and a third-level control strategy, ranked from highest to lowest priority. The first-level control strategy is a passive control strategy, where the control system sends action commands to the joint protection mechanism according to explicit passive control instructions. The second-level control strategy is an active control strategy, which is a predictive risk decision based on multi-sensor data fusion. The third-level control strategy is a real-time adjustment strategy, which dynamically fine-tunes the mechanism based on real-time sensor feedback data by calculating proportional-derivative equations in real time. This three-level control strategy enables the robot to receive passive control commands for passive joint protection as well as achieve precise autonomous control for active protection.

[0072] Furthermore, such as Figure 2 As shown, in order to prevent conflicts in control commands and achieve precise real-time autonomous control, S200 also includes the following steps:

[0073] The S210 control system executes the first-level control strategy and checks for explicit passive control commands; if so, it generates a passive control layer decision d. passive If ∈{0,1}, proceed to S240; otherwise, proceed to S220.

[0074] The S220 control system executes the second-level control strategy and calculates the active control layer decision D. active ∈{0,1};

[0075] The S230 control system executes a third-level control strategy, making real-time adjustments based on sensor data and calculating the real-time adjustment amount D. realtime ;

[0076] The S240 control system will make decisions at the passive control layer. passive ∈{0,1}, Active control layer decision D active ∈{0,1} and real-time adjustment D realtime Perform fusion calculations to obtain the final action command D. final ∈{0,1}.

[0077] Specifically, in S210, the passive control commands generated by the first-level control strategy can be deployment or retraction commands issued by the operator, deployment or retraction commands issued by the group collaborative control console, or task commands that follow a fixed formation in group collaborative operations. When the control system receives any of these task commands requesting "deploy," it sends a deployment operation command to the joint protection mechanism; when the control system receives any of these task commands requesting "retraction," it sends a retraction operation command to the joint protection mechanism.

[0078] The first-level control strategy employs rule-driven and deterministic control logic, while the passive control layer makes decisions (D). passive The formula for calculating ∈{0,1} is as follows:

[0079]

[0080] in:

[0081] C op ∈{-1,0,1}: Operator task instructions (-1 = retract, 0 = none, 1 = expand);

[0082] C gc ∈{-1,0,1}: Group console task commands (-1 = retract, 0 = none, 1 = expand);

[0083] F fmt ∈{0,1}: Group fixed formation requires task instructions (1 = need to expand to maintain formation, 0 = not needed).

[0084] To resolve conflicting action commands, the priority of control commands can also be set. For example, the priority can be set to C. op >C gc >F fmt This allows for the smooth passive control of the joint protection mechanism.

[0085] Specifically, in order to predict environmental risks and generate active control layer decisions in real time, the second-layer control strategy in S220 includes multiple risk sub-modules. Each risk sub-module outputs a risk factor, and the control system calculates based on the risk factors to obtain the active control layer decision D. active ∈{0,1}.

[0086] The second-level control strategy includes the following decision-making steps:

[0087] The S221 sensor collects and feeds back environmental or status information variables to the control system in real time.

[0088] The S222 control system calculates the risk factor for each risk submodule based on the information variables fed back from the sensors.

[0089] The S223 control system performs weighted risk calculation and threshold judgment based on risk factors to arrive at the active control layer decision D. avtive ∈{0,1}.

[0090] More specifically, in step S221, since the wheel-legged composite robot needs to walk or work in complex environments, the wheel-legged composite robot is equipped with a variety of environmental or state sensors, and the control system calculates the corresponding risk factors based on the information variables fed back by the corresponding sensors.

[0091] For example, the risk submodule includes a falling object risk submodule and a fall risk submodule, which calculates the estimated falling object hazard factor in the work area.

[0092] The falling object risk factor A is calculated using the following formula. fall and fall risk factor A trip :

[0093] Falling object risk factor A fall :

[0094] A fall =σ(R) fall -θ fall )

[0095] Where: R fall ∈[0,1] represents the falling object hazard coefficient (0 means no danger, 1 means extremely high danger), σ is the step function, and θ fall This is the threshold for the risk of falling objects.

[0096] Fall risk factor A trip :

[0097]

[0098] Where: R trip ∈[0,1] represents the fall risk coefficient based on map and road conditions, σ is the step function, and θ trip This is the fall risk threshold.

[0099] Considering that the deployment of the joint protection mechanism may affect the robot's passage through narrow paths, the risk submodule also includes a narrow path suppression module, and the risk factors in step S222 also include narrow path suppression factor I. narrow This prevents the joint protection mechanism from deploying when the robot is in a sufficiently narrow path.

[0100] Narrow Pathway Inhibitor I narrow The calculation formula is as follows:

[0101] I narrow =σ(θ) narrow -P narrow )

[0102] Where: P narrow ∈[0,1] represents the probability of passing through a narrow path (0 for open, 1 for extremely narrow and needing to be collapsed), σ is the step function, and θ narrow This is the fall risk threshold.

[0103] More specifically, in S223, the control system performs a comprehensive weighted calculation based on the risk factors in S222, and then compares it with the comprehensive weighted risk threshold to generate the active control layer decision D. active ∈{0,1}.

[0104] Active control layer decision D active The formula for calculating ∈{0,1} is as follows:

[0105]

[0106] Where, θ active To determine if the overall risk exceeds the threshold, w1 and w2 are used as weights.

[0107] In this embodiment, step S223 enables w1 and w2 to reflect the importance of different risks, and only after confirming that the robot is not currently in a narrow path that must be retracted will an active deployment command be sent to the joint protection mechanism to prevent the deployment of the joint protection mechanism from interfering with the robot's movement.

[0108] The robot joint protection method in this embodiment outputs active control layer decisions through the fusion judgment mechanism of multiple risk factors in S220, realizing the collaborative assessment of multiple risks such as falling objects, falls, and narrow paths in complex working environments; by dynamically adjusting the weight allocation of each risk factor, it takes into account both motion efficiency and joint protection.

[0109] Specifically, in S230, considering the real-time changes in risk factors, the third-level control strategy is a real-time adjustment strategy; the third-level control strategy is based on proportional-differential fine-tuning of real-time feedback, used to deal with emergencies or smooth state transitions.

[0110] The third-level control strategy includes the following calculation steps:

[0111] S231 performs real-time error calculation; the following adjustment variables are obtained:

[0112] Risk change rate:

[0113]

[0114] State deviation variable (deviation between actual and predicted gait):

[0115]

[0116] Wherein: S gait Here is the gait instability coefficient, and its predicted value is...

[0117] Adjusted variables for sudden obstacles:

[0118]

[0119] Where: V obs ∈[0,1] represents the visual real-time obstacle proximity.

[0120] S232 performs real-time adjustment calculation to obtain the real-time adjustment amount D. realtime ∈{-1,0,1}, where: -1 = strong closure, 0 = hold, 1 = strong expansion.

[0121]

[0122] Where: k i To adjust the gain in real time.

[0123] Step S230 implements a simplified PD controller that responds to situations such as a rapid increase in real-time risk, sudden road slippage, more unstable gait than expected, or the approach of a sudden obstacle. realtime Output +1, it is strongly recommended to expand immediately; otherwise, output -1 and it is recommended to withdraw.

[0124] Specifically, in S240, the action instruction D final The calculation of ∈{0,1} adopts priority arbitration, and the active control layer decision D active ∈{0,1} are superimposed onto the passive control layer decision D with a certain weight α. passive On the range {0,1}, after saturation processing, the final action instruction D is obtained. final ∈{0,1}. The calculation formula is as follows:

[0125]

[0126] in:

[0127] sta(·) is a saturation function that restricts the result to [0,1]. A value ≥ 0.5 is considered as 1 (expanded). α ∈ [0,1) is the gain value. A smaller value of α ∈ [0,1) indicates the active control layer decision D of the third-layer control strategy on the second-layer control strategy. active The correction strength for ∈{0,1} is adjusted to avoid drastic fluctuations.

[0128] The joint protection method for the wheel-legged hybrid robot in this embodiment incorporates a three-layer control strategy—passive control, active control, and real-time adjustment—in the joint protection mechanism opening and closing strategy in step S200. This allows for a comprehensive decision-making process, taking into account both the complex environment and the robot's own motion posture, to provide dynamic adaptive protection for the robot's hip joint during movement in complex terrain. This effectively reduces the risk of hip joint injury caused by collisions, overloads, or postural instability. Furthermore, by introducing state deviation variables and sudden obstacle adjustment variables, the system can achieve precise responses to the joint protection mechanism in dynamic environments. The output of the real-time adjustment quantity δ combines gait prediction deviation and the proximity of external obstacles, enhancing the environmental adaptability of the control strategy.

[0129] Example 2

[0130] This embodiment provides a joint protection method for a wheel-legged hybrid robot. The steps are basically the same as those of the joint protection method for a wheel-legged hybrid robot provided in Embodiment 1, with the difference being:

[0131] S100 also includes: when the robot performs a high-speed driving task, the control system also activates a high-speed driving stability control strategy.

[0132] Specifically, considering that during high-speed travel, the motion control of the wheels directly affects the motion state and stability of the wheeled robot due to air resistance and friction, in order to reduce the probability of the robot falling during high-speed travel and reduce the risk of joint motor damage due to falls, the high-speed travel stability control strategy of this embodiment includes: the control system dynamically calculates and adjusts the heading angle of each foot wheel in real time, thereby improving the stability of the robot during high-speed travel and reducing the risk of robot falls and joint damage; the heading angle includes the toe angle δ and the camber angle γ.

[0133] like Figure 3 As shown, the toe angle δ of the robot's foot wheel is defined as the angle between the longitudinal centerline of the foot wheel and the centerline of the robot body when viewed from below the wheeled robot. If the distance between the front point of the foot wheel and the centerline of the robot body is shorter than the distance between the rear point, it is a positive toe angle δ1; conversely, if the distance between the front point of the foot wheel and the centerline of the robot body is longer than the distance between the rear point, it is a negative toe angle δ2.

[0134] like Figure 4 As shown, the camber angle γ of the robot's foot wheel is defined as the angle between the longitudinal centerline of the foot wheel and the centerline of the robot body when viewed horizontally from the robot's horizontal direction. If the distance between the upper point of the foot wheel and the centerline of the robot body is longer than the distance between the lower point, it is a positive camber angle γ1; conversely, if the distance between the upper point of the foot wheel and the centerline of the robot body is shorter than the distance between the lower point, it is a negative camber angle γ2.

[0135] The joint protection method of the wheel-legged hybrid robot in this embodiment activates a high-speed driving stability control strategy when performing a high-speed driving task in S100. This strategy dynamically calculates and adjusts the heading angle of the foot wheels. On one hand, by dynamically calculating and adjusting the required toe angle δ of each foot wheel, it effectively prevents separation and swaying phenomena during the robot's movement, thus ensuring the robot's stability and safety. On the other hand, by dynamically calculating and adjusting the required camber angle γ of each foot wheel, it optimizes the contact area between the foot wheel and the ground, enhancing grip, especially effectively reducing the risk of sideslip when driving on slopes or uneven surfaces. Through the fusion control of the toe angle δ and the camber angle γ, the wheel-legged robot can improve its anti-slip, anti-yaw, and pitch stability during high-speed movement, high-speed cornering, and handling uneven road surfaces. This simultaneously enhances its road-keeping ability, lateral stability, and safety, thereby improving the robot's high-speed driving stability and reducing the risk of falls and joint injuries.

[0136] It is understandable that introducing the toe angle δ and camber angle γ of the foot-end wheels into a wheel-legged robot will affect its dynamic characteristics during high-speed travel. When establishing the motion model, the influence of these angles on tire forces, kinematics, and dynamics needs to be considered. The wheel-legged robot adopts a hybrid wheel-leg motion, with wheel motion as the main mode of movement during high-speed travel, while the legs maintain a fixed posture.

[0137] The kinematic model of the wheeled robot after introducing the toe angle δ and camber angle γ of the foot-end wheels is as follows:

[0138] 1. Foot wheel speed relationship

[0139] For each foot-end wheel, its rolling direction changes due to the toe angle δ and camber angle γ. Definition:

[0140] The rolling direction of the foot wheel is in the local coordinate system.

[0141] The toe angle δ and camber angle γ are used to transform the wheel speed from the local coordinate system to the global coordinate system through the rotation matrix R(δ,γ).

[0142] Foot wheel linear velocity v w,i The components in the global coordinate system are:

[0143]

[0144] Where R z and R x These are the rotation matrices around the z-axis (yaw) and x-axis (roll), respectively.

[0145] 2. Overall kinematic model of the robot

[0146] The robot's speed v = [v x,v y ,ω] T The speed is determined by the combined speeds of all the foot-end wheels, where v x v y ω and ω represent the robot's linear velocity along the x-axis, linear velocity along the y-axis, and angular velocity (yaw rate) about the z-axis, respectively. Mapped using the Jacobian matrix J:

[0147]

[0148] The construction of the Jacobian matrix needs to take into account the correction of the wheel velocity direction by the toe angle and camber angle.

[0149] Dynamic model:

[0150] (1) Tire force model

[0151] Toe angle and camber angle affect the tire's lateral characteristics and vertical force distribution. A simplified linear tire model is used:

[0152] Lateral force:

[0153] F y,i =-C α α i

[0154] Where α i It is the sideslip angle, which is affected by the toe angle and lateral tilt angle.

[0155]

[0156] k γ It is the outward stiffness coefficient.

[0157] Vertical force:

[0158] An outward tilt angle can cause uneven distribution of vertical force, which can be calculated using static equilibrium.

[0159]

[0160] (2) Dynamic equations

[0161] The robot's equation of motion is:

[0162]

[0163] Where F i It is the resultant force (including longitudinal and lateral forces) of the i-th tire, r i It is the tire position vector.

[0164] Furthermore, considering that robots are prone to lateral drift when traveling at high speeds in straight lines, the high-speed driving stability control strategy in the S100 also includes:

[0165] When the robot is in a high-speed straight-line cruising state, the toe angle δ of each foot wheel is assigned to zero or a small positive toe angle δ1. For example, 0 ≤ toe angle δ ≤ 10°.

[0166] By assigning zero or a small positive toe angle δ1 to each foot wheel, the directional stability of the robot in straight-line travel can be enhanced, and the suppression effect on lateral drift can be improved.

[0167] Furthermore, considering that robots are prone to understeering when turning at high speeds, the high-speed driving stability control strategy in the S100 also includes:

[0168] When the robot makes a high-speed turn, a different toe angle δ is assigned to the inner and outer wheels. Specifically, the inner wheel is assigned a negative toe angle δ2, and the outer wheel is assigned a positive toe angle δ1. For example, the toe angle of the inner wheel is 2° to 4° larger than that of the outer wheel.

[0169] By assigning different toe angles to the inner and outer wheels, a virtual "Ackermann geometry" enhancement effect can be created, generating a yaw moment in the same direction as the turning direction, assisting in turning and suppressing understeer.

[0170] Furthermore, considering that robots are prone to sideslip when cornering at high speeds, the high-speed driving stability control strategy in the S100 also includes:

[0171] When the fuselage yaws excessively, the toe angle δ of the foot wheel on the yaw direction is adjusted independently. Here, a negative toe angle δ2 is applied relative to the rear wheel in the yaw direction, and a positive toe angle δ1 is applied relative to the front wheel in the yaw direction.

[0172] By independently adjusting the toe angle δ of the foot wheel on the yaw direction, a corrective yaw moment can be generated. The yaw moment can effectively suppress fuselage sideslip and improve handling stability when cornering at high speed.

[0173] Furthermore, considering that the robot's ability to support itself is affected by tilting when traveling at high speeds on uneven surfaces, the high-speed stability control strategy in the S100 also includes:

[0174] When the road surface is uneven or the robot tilts to one side, apply a negative camber angle γ2 to the foot wheel on the lower side and a positive camber angle γ1 to the foot wheel on the higher side.

[0175] By adjusting the camber angle γ of the two foot wheels respectively, the tire surface can make better contact with the road surface, generating greater lateral force, resisting the tendency to roll, and improving cornering support.

[0176] Furthermore, considering that robots are prone to veering off course during emergency braking, the high-speed driving stability control strategy in the S100 also includes:

[0177] When the robot needs to brake urgently, a small positive toe angle δ1 is given to all foot wheels.

[0178] By applying a small positive toe angle δ to all foot wheels, directional stability during braking can be improved, preventing deviation.

[0179] The joint protection method for the wheel-leg hybrid robot in this embodiment, by setting toe-in and camber adjustment strategies under various conditions in the high-speed driving stability control strategy of S100, can effectively cope with complex working conditions such as steering, sideslip, and uneven road surfaces during high-speed driving, achieving precise intervention in the robot's posture and reducing the risk of robot falls and joint damage.

[0180] Example 3

[0181] This embodiment provides a wheel-leg hybrid robot, which employs the joint protection methods of the wheel-leg hybrid robots in Embodiments 1 and 2 for protection, such as... Figure 5 As shown, the wheel-leg composite robot includes a body 1, a joint protection mechanism 2, a wheel-leg actuator 3, and a control system.

[0182] like Figure 6 As shown, in order to provide controllable physical protection for the robot's hip joint, the joint protection mechanism 2 includes a protection component 21, a drive component 22, and a locking component 23; the protection component 21 includes a protective cover 211, the drive component 22 is capable of driving the protective cover 211 to unfold or retract outside the robot's hip joint, and the locking component 23 is used to lock the position of the protective cover 211 when it retracts.

[0183] Preferably, in order to smoothly and quickly execute the action commands sent by the control system, such as Figure 6 As shown, the protective assembly 21 also includes a first push rod 212, a second push rod 213, and a mounting plate 214. The first push rod 212 and the second push rod 213 are arranged in parallel and both ends are hinged to the protective cover 211 and the mounting plate 214, respectively, so that the protective cover 211, the first push rod 212, the second push rod 213, and the mounting plate 214 are connected to form a parallelogram linkage structure. The mounting plate 214 is fixedly connected to the body 1. The driving component 22 drives the first push rod 212 to rotate, so that the protective cover 211 can be unfolded and retracted.

[0184] For example, such as Figure 7As shown, taking a quadruped robot as an example, two sets of protective components 21 are respectively set on both sides of the robot body. Mounting plates 214 are fixed to both sides of the robot body, and their dimensions can be designed according to different robot models; each mounting plate 214 has a protective cover 211, a first push rod 212, a second push rod 213, and a drive component 22 at both ends. The structure of the protective cover 211 is designed according to the required protection orientation of the robot and the size and installation method of key components such as motors; the material can be selected according to the protection level requirements. The drive component 22 adopts a linear cylinder assembly, with the extended end of the linear cylinder hinged to the first push rod 212; as shown... Figure 6 As shown, the locking member 23 is mounted on the mounting plate 214. Preferably, the locking member 23 includes a magnetic energy storage structure, which can fix the protective cover 211 by electromagnetic force when the protective device is retracted, and press down the spring to store elastic energy, and release and pop out the protective cover 211 when necessary.

[0185] Figure 7 This is a schematic diagram of the joint protection mechanism 2 in its deployed state. Figure 8 This is a schematic diagram of the joint protection mechanism 2 in the retracted state.

[0186] In the initial state, the joint protection mechanism 2 is in the retracted state, and the extended end of the drive member 22 retracts, causing the first push rod 212 and the second push rod 213 at both ends of the mounting plate 214 to fold relative to each other in the direction of the mounting plate 214. This causes the two protective covers 211 on the same side of the body 1 to close together and abut against the side of the body 1. The protective covers 211 are locked to the mounting plate 214 by the electromagnetic force of the magnetic energy storage structure on the locking member 23, and the spring is compressed to store elastic energy. During the execution of S200 in embodiment 1, when the control system sends an unfolding action command to the joint protection mechanism 2, the magnetic energy storage structure of the locking member 23 quickly unlocks, the spring quickly springs open, and at the same time, the extended end of the drive member 22 quickly extends, causing the first push rod 212 and the second push rod 213 to drive the protective covers 211 to unfold parallel to the direction of the robot's hip joint. Figure 7 As shown, the protective shield 211 extends to the outside of the hip joint, providing physical protection for the robot's hip joint. When the control system sends a retraction command to the joint protection mechanism 2, the extended end of the drive member 22 quickly retracts, and the joint protection mechanism 2 retracts to its initial state, as shown. Figure 8 As shown, the protective cover 211 is locked to both sides of the fuselage 1.

[0187] The wheel-leg hybrid robot of this embodiment, by setting up a joint protection mechanism 2 with a three-dimensional parallelogram structure, can smoothly implement the joint protection method of Embodiment 1. This allows the joint protection mechanism 2 to execute the control system's motion commands agilely and stably, while also maximizing space utilization. Furthermore, the joint protection mechanism 2 can be connected to the robot body 1 via a mounting plate 214 using quick-connect methods such as bolts. In normal operating environments, the joint protection mechanism 2 can serve as a spare part for the robot, allowing for rapid installation when needed, thus improving the robot's flexibility.

[0188] Furthermore, in order to adopt the joint protection method of Embodiment 2, and to adjust the toe angle δ and camber angle γ of the foot wheels, thereby reducing the probability of the robot falling and damaging the joint motors during high-speed travel, such as... Figure 9 As shown, the wheel-leg actuator 3 of this embodiment has five degrees of freedom. The wheel-leg actuator 3 includes a joint 31, a thigh 32, a lower leg 33, and a wheel foot 34. The joints include a lateral swing joint 311, a forward swing joint 312, a knee joint 313, an ankle joint 314, a foot rotation joint 315, and a foot wheel rotation joint 316.

[0189] Among them, the motor of the lateral swing joint 311 controls the abduction movement of the leg, thereby adjusting the lateral tilt angle γ of the foot wheel 341; the motor of the foot rotation joint 315 controls the horizontal rotation of the foot wheel 341, thereby adjusting the positive and negative toe angle δ of the foot wheel; the motor of the forward swing joint 312 controls the forward or backward swing of the leg; the telescopic joint motor 317 controls the combined movement of the knee joint 313 and the ankle joint 314 by driving the thigh linkage; and the motor of the foot wheel rotation joint 316 controls the rotation of the foot wheel 341.

[0190] The wheeled robot of this embodiment, by setting up a wheel-leg actuator with six joints and five degrees of freedom, can flexibly adjust the toe angle δ and camber angle γ of the foot wheel, realize real-time control of the driving posture, improve the stability of the robot at high speed, and reduce the risk of robot falling and joint damage.

[0191] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A joint protection method for a wheel-legged hybrid robot, characterized in that, The method comprises the following steps: S100, when the robot performs a task, the control system starts an opening and closing strategy of the joint protection mechanism; S200, the control system sends an action instruction to the joint protection mechanism according to the opening and closing strategy of the joint protection mechanism; S300, the joint protection mechanism executes the action instruction; if an unfolding instruction is executed, the hip joint of the robot is physically protected; if a retraction instruction is executed, the hip joint of the robot is exposed externally. 2.The joint protection method of the wheel-legged composite robot according to claim 1, wherein, The opening and closing strategy of the joint protection mechanism in S100 comprises, in order of priority from high to low, a first layer control strategy, a second layer control strategy and a third layer control strategy.

3. The joint protection method of the wheel-legged composite robot according to claim 2, characterized in that, The first layer control strategy is a passive control strategy, and the control system sends an action instruction to the joint protection mechanism according to an explicit passive control instruction.

4. The joint protection method of the wheel-legged composite robot according to claim 3, characterized in that, The second layer control strategy is an active control strategy, which is a predictive risk decision based on multi-sensor data fusion.

5. The joint protection method of the wheel-legged composite robot according to claim 4, characterized in that, The third layer control strategy is a real-time adjustment strategy, which dynamically fine-tunes in real time based on sensor feedback data. 6.The joint protection method of the wheel-legged composite robot according to claim 5, wherein, S200 further comprises the following steps: S210 Control system executes the first layer control strategy, checks whether there is a clear passive control instruction; if yes, generates passive control layer decision D passive ∈ {0,1}, enters S240; if no, enters S220; S220 the control system executes the second layer control strategy, and calculates the active control layer decision D active ∈ {0, 1}. S230 controls the system to execute the third layer control strategy, and calculates the real-time adjustment amount D according to the sensor data realtime ; S240 The control system fuses the passive control layer decision D passive ∈{0,1} and the active control layer decision D active ∈{0,1} and the real-time adjustment amount D realtime performs fusion calculation to obtain the final action instruction D final ∈{0,1}.

7. The joint protection method of the wheel-legged composite robot according to claim 1, characterized in that, S100 further comprises: when the robot performs a high-speed driving task, the control system further starts a high-speed driving stability control strategy.

8. A wheel-legged hybrid robot, characterized in that, The joint protection method of the wheel-leg composite robot according to any one of claims 1 to 7 is used for protection, and the wheel-leg composite robot comprises a body (1), a joint protection mechanism (2) and a control system.

9. The wheel-legged hybrid robot according to claim 8, wherein, The joint protection mechanism (2) comprises a protection assembly (21), a driving member (22) and a locking member (23).

10. The wheel-legged composite robot according to claim 9, characterized in that, The protection assembly (21) comprises a protection cover (211), the driving member (22) can drive the protection cover (211) to unfold or retract outside the hip joint of the robot, and the locking member (23) can lock the protection cover (211) in the retracted position.

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