A flying robot and method based on leg-foot landing

Abstract

The present invention relates to the field of flying robots, and discloses a flying robot and method based on leg-foot landing. The method comprises: obtaining the forward velocity of the flying robot after landing, and obtaining a footfall position sequence based on the landing surface; obtaining a gait time sequence and a desired zero-torque point trajectory based on the footfall position sequence and the forward velocity, and obtaining a foot-end motion trajectory; calculating a horizontal thrust attenuation trajectory based on the forward velocity; obtaining a horizontal center of mass trajectory based on the desired zero-torque point trajectory and the horizontal thrust attenuation trajectory; calculating a center of mass height trajectory based on the footfall position sequence and the center of mass horizontal trajectory; obtaining a desired joint angle trajectory based on the center of mass trajectory and the foot-end motion trajectory; and the flying robot performing a walking buffer motion based on the horizontal thrust attenuation trajectory and the desired joint angle trajectory, thereby achieving landing. The present invention can solve the problem of a flying robot landing at a high forward velocity on uneven terrain.

Description

Technical Field

[0001] The present invention relates to the technical field of flying robots, and in particular to a flying robot and a method based on leg-foot landing. Background Art

[0002] Flying robots possess powerful aerial locomotion capabilities, but after completing their missions, they must land on the ground. Therefore, the smooth transition from aerial mode to land mode is crucial. The robot flies through the air at a certain forward velocity. When it needs to quickly land at its destination, it must transition from aerial mode to land mode, meaning it must land at a constant forward velocity. The challenge facing the robot is that after landing, it still has a certain initial velocity, requiring it to decelerate and stop quickly. Rapid deceleration can generate significant inertial forces, causing it to fall forward, which can be disastrous for the robot's transition from aerial mode to land mode. Currently, there are two main methods for landing aircraft. One is for multi-rotor aircraft to land vertically by controlling the landing speed. However, this landing method requires the vertical speed to be close to zero before landing. Otherwise, the aircraft cannot offset the residual kinetic energy after landing and will overturn. This method also consumes a lot of energy and has poor maneuverability on the ground. The other landing method is for fixed-wing aircraft to use wheeled landing legs to complete the landing by gliding for a long distance. Although this method uses wheels to buffer the landing kinetic energy, the gliding runway is long and requires high ground flatness. Moreover, gliding is a passive method for buffering kinetic energy. These methods have their shortcomings and cannot meet the requirements of flying robots for fast and stable landing at a certain initial velocity under limited landing surface conditions.

[0003] Current flying robots often adopt the following strategies when transitioning from aerial mode to land mode: 1) The center of mass velocity is reduced to zero when landing in the air, so that the robot's speed is close to zero when landing. This method completes deceleration during landing, and requires a long time and a large space to complete trajectory tracking in the air. 2) In order to adapt to uneven terrain for vertical takeoff and landing, the flying robot adopts an actively retractable leg-foot-type buffer landing gear, such as the patent "CN111470035B", which buffers the landing kinetic energy through an adaptive landing gear buffer mechanism, but cannot complete landing under conditions of a large horizontal forward speed. The above methods have their own limitations and cannot complete the landing buffer problem that can adapt to a large forward speed under uneven terrain. Summary of the Invention

[0004] The primary purpose of the present invention is to overcome the problems existing in the prior art and provide a flying robot and method based on leg-foot landing. The present invention can solve the problem of landing a flying robot at a high forward speed on uneven terrain and ensure the stability of the flying robot's posture.

[0005] In order to achieve the above object, the present invention provides a method based on leg-foot landing, the method comprising:

[0006] Obtaining the forward velocity of the flying robot after landing, and obtaining a position sequence of the landing points of the flying robot according to the landing surface;

[0007] Obtaining a gait time sequence and an expected zero-moment point trajectory of the flying robot based on the footfall position sequence and the forward velocity, and obtaining a foot-end motion trajectory of the flying robot based on a cycloid equation;

[0008] calculating a horizontal thrust decay trajectory based on the forward velocity;

[0009] Obtaining a center of mass horizontal trajectory according to the desired zero-moment point trajectory and the horizontal thrust attenuation trajectory;

[0010] Calculating the center of mass height trajectory of the flying robot using a virtual ramp method based on the foothold position sequence and the center of mass horizontal trajectory;

[0011] Performing inverse processing on the center of mass trajectory and the foot end motion trajectory to obtain a desired joint angle trajectory of the flying robot, wherein the center of mass trajectory is obtained based on the center of mass horizontal trajectory and the center of mass height trajectory;

[0012] The flying robot performs a walking buffering motion based on the horizontal thrust attenuation trajectory and the desired joint angle trajectory, thereby achieving landing, including: the joint motors of the flying robot drive the flying robot to perform a walking motion according to the desired joint angle trajectory; the controller of the thrust device drives the front thruster and the rear thruster to generate corresponding thrust and drives the rotary motor to change the thrust direction according to the horizontal thrust attenuation trajectory and posture data generated by the posture sensor, thereby achieving buffering the inertial force generated by landing deceleration and ensuring the posture of the flying robot, thereby achieving landing;

[0013] The flying robot comprises a thrust device, a flying robot body and a posture sensor, wherein the thrust device is arranged on the leg and foot mechanism of the flying robot body, the posture sensor is arranged on the flying robot body, the thrust device is used to generate forward thrust and backward thrust, and control the landing of the flying robot by controlling the magnitude of the forward thrust and backward thrust, the posture sensor is used to generate posture data of the flying robot and send the posture data to the thrust device, and the thrust device ensures the posture of the flying robot according to the posture data; the thrust device comprises: a rear thruster (1), a front thruster (2), a control mechanism and a connecting rod (4), the rear thruster (1) and the front thruster (2) are respectively connected to the two ends of the connecting rod (4) through a rotating pair; the control mechanism is connected to the middle position of the connecting rod (4), and the control mechanism is used to control the thrust direction and thrust magnitude generated by the rear thruster (1) and the front thruster (2); the control mechanism comprises: a rotating motor (3), a controller (5), a rocker arm, a first battery (6) and a second battery (7), the output of the rotating motor (3) The shaft is fixedly connected to the rocker arm, the rocker arm is rotatably connected to the connecting rod (4), and the rotating motor (3) drives the connecting rod (4) to rotate through the rocker arm, thereby controlling the rotation direction of the rear propeller (1) and the front propeller (2), and further controlling the thrust direction; the first signal output end of the controller (5) is connected to the signal input end of the rotating motor (3), and the second signal output end of the controller (5) is respectively connected to the signal input end of the rear propeller (1) and the signal input end of the front propeller (2), and the rotating motor (3) The invention relates to a vehicle control system comprising: a vehicle control system comprising: a first control signal sent by the controller (5), and a vehicle control system for controlling the rotation direction of the rear propeller (1) and the front propeller (2) according to the first control signal; a vehicle control system for controlling the rotation direction of the rear propeller (1) and the front propeller (2) according to the first control signal; a vehicle control system for controlling the rotation direction of the rear propeller (1) and the front propeller (2) according to the second ...

[0014] Furthermore, the acquiring of the gait time series and the expected zero-moment point trajectory of the flying robot based on the foothold position sequence and the forward velocity specifically includes:

[0015] Obtaining the step length of the gait cycle based on the footfall position sequence , step width Ji Bu Gao ;

[0016] Calculate the gait time of the first step of the flying robot after landing according to the forward speed and the step length , the specific calculation method is as follows:

[0017]

[0018] in, is the step length, is the forward speed;

[0019] Determine the gait time of the first step Is it greater than the minimum gait time? If it is greater than, then the gait time of the first step Calculate the gait time series as the benchmark; otherwise, use the minimum gait time The gait time series is calculated as the benchmark, and the gait time of any step in the gait cycle is satisfy ;

[0020] Stride length according to gait cycle , step width , Bugao and the gait time series to generate an expected zero-moment point trajectory, the zero-moment point trajectory includes The zero moment point trajectory ZMPX and The zero moment point trajectory ZMPY in the direction.

[0021] Furthermore, according to the step length of the gait cycle , step width , Bugao The desired zero-moment point trajectory is generated from the gait time series, including assuming that the initial left foot landing point is , the right foot lands , then in During the gait cycle, calculate The expected zero moment point trajectory ZMPX in the direction is as follows:

[0022]

[0023] Among them, calculation The desired zero moment point trajectory ZMPY in the direction is as follows:

[0024] .

[0025] Furthermore, the calculating of the horizontal thrust attenuation trajectory based on the forward velocity specifically includes:

[0026] The initial horizontal thrust is calculated based on the forward velocity as follows:

[0027]

[0028] in, is the minimum initial velocity that requires the use of thrust buffer, is the proportionality coefficient;

[0029] Calculate the horizontal thrust attenuation trajectory based on the initial horizontal thrust :

[0030]

[0031] in, is the current time, , is the total time of horizontal thrust action.

[0032] Furthermore, obtaining the center of mass horizontal trajectory according to the expected zero-moment point trajectory and the horizontal thrust attenuation trajectory specifically includes:

[0033] A walking planning model is constructed, and a zero-moment point equation is calculated based on the walking planning model. The zero-moment point equation is as follows:

[0034]

[0035] in, is the zero moment point of the flying robot, is the height of the center of mass, is the horizontal component of thrust, is the vertical component of thrust;

[0036] Linearizing the zero-moment point equation to obtain a linear zero-moment point equation;

[0037] A center-of-mass horizontal trajectory is obtained using an LQR planner based on the desired zero-moment point trajectory, the horizontal thrust attenuation trajectory, and the linear zero-moment point equation.

[0038] Furthermore, the calculation of the center of mass height trajectory of the flying robot using a virtual slope method based on the foothold position sequence and the center of mass horizontal trajectory specifically includes:

[0039] Obtaining the height position of the foothold according to the foothold position sequence;

[0040] Connecting the height positions of the landing points to form a virtual slope;

[0041] Calculate the slope of two adjacent footfall points, and calculate the center of mass height trajectory based on the slope and the horizontal center of mass trajectory. The calculation method is as follows:

[0042]

[0043] in, are the slopes of the two foot points, is the centroid height.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. By introducing a rotatable propulsion device as landing cushion thrust, a walking planning model is established based on a propulsor-based legged robot. The dynamic equation containing the thrust term is derived and linearized. The attenuated horizontal thrust is used to offset the inertial force generated by walking deceleration. Combined with the gait time optimization method, an LQR control planner is used to obtain the horizontal trajectory of the center of mass that can track the desired zero-torque point trajectory. This allows the robot to complete stable walking cushioning at a higher forward speed, thereby achieving the robot's ability to complete cushioning and stop in a shorter time. This solves the cushioning problem of flying robots landing at high initial velocities under limited terrain conditions.

[0046] 2. Based on the landing cushioning conditions at non-zero forward speeds, the walking time is optimized to enable the leg and foot movements to respond quickly to keep up with the center of mass speed, avoiding rapid deceleration that causes excessive inertia torque and causes falls, thereby ensuring the stability of the flying robot during landing. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a flow chart of a method for leg-foot landing according to embodiment 2 of the present invention;

[0048] Figure 2 1 is a structural diagram of a thrust device according to embodiment 1 of the present invention;

[0049] Figure 3 is the walking planning model of embodiment 2 of the present invention;

[0050] Figure 4 Schematic diagram of walking buffering action according to embodiment 2 of the present invention. DETAILED DESCRIPTION

[0051] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0052] In the description of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0053] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0054] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0055] Example 1

[0056] An embodiment of the present invention provides a flying robot based on leg-foot landing, comprising: a thrust device, a flying robot body, and a posture sensor. The thrust device is arranged on the leg-foot mechanism of the flying robot body, and the posture sensor is arranged on the flying robot body. The thrust device is used to generate forward thrust and backward thrust, and control the landing of the flying robot by controlling the magnitude of the forward thrust and backward thrust. The posture sensor is used to generate posture data of the flying robot and send the posture data to the thrust device. The thrust device ensures the posture of the flying robot based on the posture data.

[0057] Furthermore, the thrust device includes: a rear thruster 1, a front thruster 2, a control mechanism and a connecting rod 4. The rear thruster 1 and the front thruster 2 are respectively connected to the two ends of the connecting rod 4 through a rotating joint; the control mechanism is connected to the middle position of the connecting rod 4. The control mechanism is used to control the thrust direction and thrust size generated by the rear thruster 1 and the front thruster 2. The thrust device is specifically shown in Figure 2 .

[0058] Furthermore, the control mechanism includes: a rotating motor 3, a controller 5, a rocker arm, a first battery 6 and a second battery 7,

[0059] The output shaft of the rotary motor 3 is fixedly connected to the rocker arm, and the rocker arm is rotatably connected to the connecting rod 4. The rotary motor 3 drives the connecting rod 4 to rotate through the rocker arm, thereby controlling the rotation direction of the rear propeller 1 and the front propeller 2, and further controlling the thrust direction;

[0060] The first signal output end of the controller 5 is connected to the signal input end of the rotating motor 3, and the second signal output end of the controller 5 is connected to the signal input end of the rear propeller 1 and the signal input end of the front propeller 2 respectively. The rotating motor 3 receives the first control signal sent by the controller 5 and controls the rotation direction of the rear propeller 1 and the front propeller 2 according to the first control signal. The rear propeller 1 and the front propeller 2 receive the second signal sent by the controller 5 and change the thrust generated by the rear propeller 1 and the front propeller 2 according to the second signal.

[0061] The first battery 6 is used to power the rear thruster 1 and the front thruster 2 , and the second battery 7 is used to power the controller 5 .

[0062] This embodiment introduces a thrust device for the flying robot. When facing uneven terrain, the thrust device can generate a front and rear thrust difference to maintain the robot's walking stability and offset the inertial force generated by walking deceleration, so that the robot can complete stable walking buffering at a higher forward speed, thereby enabling the robot to complete buffering and stop in a shorter time, solving the buffering problem of the flying robot landing at a higher initial velocity under limited terrain conditions.

[0063] Example 2

[0064] like Figure 1 As shown, a method based on leg-foot landing in a preferred embodiment of the present invention is based on a flying robot based on leg-foot landing in embodiment 1, comprising:

[0065] Step S1: obtaining the forward velocity of the flying robot after landing, and obtaining the position sequence of the landing points of the flying robot according to the landing surface;

[0066] In a feasible embodiment, S1 specifically includes: the flying robot first needs to perceive the surrounding environment through sensors (such as cameras, lidar, etc.) to obtain information such as the terrain and topography of the ground where it is about to land; based on the perceived environmental information, the robot plans a feasible walking path, which will avoid obstacles as much as possible while ensuring the stability and safety of the robot; on the planned path, the flying robot selects a series of suitable landing points, which should meet the support requirements of the robot while preventing the robot from falling into an unstable state; the selected landing points are recorded in the walking order to form a landing point position sequence.

[0067] Step S2: obtaining the gait time series and the expected zero-moment point trajectory of the flying robot based on the foot position sequence and the forward velocity, and obtaining the foot end motion trajectory of the flying robot based on the cycloid equation;

[0068] In a feasible embodiment, S2 specifically includes:

[0069] Obtaining the step length of the gait cycle based on the sequence of footfall positions , step width Ji Bu Gao ;

[0070] Calculate the gait time of the first step of the flying robot after landing based on the forward speed and the step length , the specific calculation method is as follows:

[0071]

[0072] in, is the step length, is the forward speed;

[0073] Determine the gait time of the first step Is it greater than the minimum gait time? If it is greater than, then the gait time of the first step Calculate the gait time series for the baseline, and make the expected forward velocity in the subsequent gait Gradually decrease and calculate the corresponding gait time: ,because If it decreases step by step, the gait time will gradually increase. In the last step, the step length is set to zero, and the gait time series of N steps is obtained. ; Otherwise, the minimum gait time The gait time series is calculated as the benchmark. The gait time at this time is limited and cannot completely buffer the inertia moment generated by the deceleration of the center of mass. The gait time of N steps thereafter is It needs to be increased based on the minimum gait time. While reducing The gait time limit will not be exceeded, that is, the gait time of any step in the gait cycle satisfy , where the minimum gait time It can be calculated as follows:

[0074] ,

[0075] in: To satisfy the shortest time constraint, is the step length, is the maximum linear velocity that the robot foot can achieve in the x direction.

[0076] Maximum gait time It can be calculated as follows:

[0077] ,

[0078] in: is the minimum linear velocity that can be achieved by the robot foot in the x direction.

[0079] Stride length according to gait cycle , step width , Bugao and the gait time series to generate an expected zero-moment point trajectory, the zero-moment point trajectory includes The zero moment point trajectory ZMPX and The zero moment point trajectory ZMPY in the direction, specifically, assuming that the initial left foot landing point is , the right foot lands , then in During the gait cycle, calculate The expected zero moment point trajectory ZMPX in the direction is as follows:

[0080]

[0081] Among them, calculation The desired zero moment point trajectory ZMPY in the direction is as follows:

[0082] .

[0083] Step S3: Calculate the horizontal thrust attenuation trajectory according to the forward velocity;

[0084] In a feasible embodiment, S3 specifically includes:

[0085] The initial horizontal thrust is calculated based on the forward velocity as follows:

[0086]

[0087] in, is the minimum initial velocity that requires the use of thrust buffer, is the proportionality coefficient;

[0088] Calculate the horizontal thrust decay trajectory based on the initial horizontal thrust :

[0089]

[0090] in, is the current time, , is the total time of horizontal thrust action.

[0091] Step S4: obtaining a center of mass horizontal trajectory according to the desired zero-moment point trajectory and the horizontal thrust attenuation trajectory;

[0092] In a feasible embodiment, S4 includes: Figure 3 and Figure 4 As shown, a walking planning model is constructed. This model generates a torque acting on the center of mass based on the front-to-back thrust difference or horizontal thrust to offset the inertial torque caused by the center of mass deceleration. Combining gait time optimization with a thrust-based gait buffering planning method ultimately achieves robot center of mass trajectory planning at higher forward speeds, allowing the robot to complete buffering actions and stop in a faster time. The walking speed buffering method based on the thrust-based inverted pendulum model is as follows:

[0093] The two thrusters of the thrust device are arranged in front and behind its waist, which has forward thrust. and back thrust , the thrust can rotate in the pitch direction and generate horizontal thrust. The horizontal thrust can generate torque on the zero torque point, and the inertia torque generated by the robot deceleration is offset by the horizontal thrust torque. Assuming that the center of mass of the robot is located at the waist and the legs are simplified to leg links, the walking buffer model based on the thruster is as shown in the attached figure. Figure 3 shown.

[0094] According to the above model, when the robot is walking at a reduced speed, its zero torque point (i.e., the point on the sole of the foot) point) is subject to gravitational moment , the moment of inertia generated by the center of mass acceleration , the torque generated by horizontal thrust And vertical thrust torque According to the definition of the zero moment point, the sum of the moments at the zero moment point of the robot's foot is zero:

[0095]

[0096] in:

[0097]

[0098] in:

[0099]

[0100] is the horizontal component of thrust, is the vertical component of thrust; is the rotation angle of the thrust relative to the vertical direction.

[0101] The zero moment point of the robot in the x direction is is within the support polygon of the sole of the foot, then:

[0102]

[0103] in, is the position of the heel in the x direction, is the toe position in the x direction.

[0104] According to the expressions of each moment, we can get:

[0105]

[0106] The thrust term controls the position of the zero moment point. According to the above formula, the horizontal thrust moment has the opposite sign to the inertia moment. Therefore, when the robot generates a large inertia moment due to deceleration, its zero moment point The value may exceed the support polygon of the robot's foot, i.e. At this time, the moment of inertia can be offset by the moment generated by the horizontal thrust, so that Stay within the support polygon.

[0107] Arrangement available and the center of mass state and thrust The relationship is:

[0108]

[0109] From the above formula, we can know that the robot's landing walking motion is In addition to the center of mass state Related to vertical thrust and horizontal thrust Due to the existence of horizontal thrust The role of With horizontal thrust Therefore, when Due to the acceleration of the robot's center of mass when landing Excessive changes lead to When it exceeds our expected position, we can control To control the size Position so that the ZMP position is within the foot support area of ​​the robot.

[0110] Linearizing the zero-moment point equation to obtain a linear zero-moment point equation;

[0111] Specifically, the above zero moment point equation is a nonlinear equation, because Other variables in the equation 、 There is coupling, so let and is a constant, then is a constant, then let The linear zero moment point equation can be obtained:

[0112]

[0113] Based on the desired zero moment point trajectory, the horizontal thrust decay trajectory and the linear zero moment point equation, the LQR planner is used to obtain the center of mass horizontal trajectory.

[0114] First, the target zero torque point reference value for the next N steps is constructed based on the expected zero torque point trajectory and the horizontal thrust attenuation trajectory. :

[0115]

[0116] in, For the horizontal thrust attenuation trajectory, the target zero torque point reference value is As a feedforward compensation term;

[0117] Then, the cost function of the system is designed according to the LQR control theory:

[0118]

[0119] Next, solve the above cost function to the minimum value, solve the Riccati equation of the system in the infinite time domain according to the optimal control, and obtain the gain and , using the calculated gain and , calculate the control input for:

[0120]

[0121] Enter Substitute the state equation of the continuous system to obtain the horizontal center of mass trajectory, where the state equation is as follows:

[0122]

[0123] Step S5: Based on the footfall position sequence and the center-of-mass horizontal trajectory, a virtual slope method is used to calculate the center-of-mass height trajectory of the flying robot;

[0124] In a feasible embodiment, S5 specifically includes: obtaining a height position of the foothold according to the foothold position sequence;

[0125] Connecting the height positions of the landing points to form a virtual slope;

[0126] Calculate the slope of two adjacent footfall points, and calculate the center of mass height trajectory based on the slope and the horizontal center of mass trajectory. The calculation method is as follows:

[0127]

[0128] in, are the slopes of the two foot points, is the centroid height. So far, the centroid height trajectory is obtained, which changes with the height of the uneven terrain.

[0129] Step S6: performing inverse processing on the center of mass trajectory and the foot end motion trajectory to obtain the desired joint angle trajectory of the flying robot, wherein the center of mass trajectory is obtained based on the center of mass horizontal trajectory and the center of mass height trajectory;

[0130] In a feasible embodiment, the center of mass trajectory (including the center of mass trajectory in the X, Y, and Z directions) is obtained by combining the center of mass horizontal trajectory and the center of mass height trajectory.

[0131] Step S7: The flying robot performs walking buffering motion based on the horizontal thrust attenuation trajectory and the expected joint angle trajectory, thereby achieving landing.

[0132] In a feasible embodiment, the joint motors of the flying robot drive the flying robot to perform walking movements according to the desired joint angle trajectory; the controller of the thrust device drives the front thrusters and the rear thrusters to generate corresponding thrust and drives the rotary motor to change the thrust direction according to the horizontal thrust attenuation trajectory and the posture data generated by the posture sensor, thereby buffering the inertial force generated by landing deceleration and ensuring the posture of the flying robot, thereby achieving landing.

[0133] This embodiment introduces a rotatable propulsion device as the thrust for landing buffering, establishes a walking planning model based on a propeller-based leg-foot robot, derives a dynamic equation containing a thrust term and performs linearization processing, uses the attenuated horizontal thrust to offset the inertial force generated by walking deceleration, and combines the gait time optimization method. The LQR control planner is used to obtain the horizontal trajectory of the center of mass that can track the desired zero-torque point trajectory, so that the robot can complete stable walking buffering at a higher forward speed, thereby enabling the robot to complete buffering and stop in a shorter time, solving the buffering problem of the flying robot landing at a higher initial velocity under limited terrain conditions; and also based on the landing buffering situation at a non-zero forward speed, by optimizing the walking time, the leg-foot movement responds quickly to keep up with the center of mass speed, avoiding rapid deceleration and causing excessive inertia torque to fall, thereby ensuring the stability of the flying robot during landing.

[0134] Example 3

[0135] An embodiment of the present invention further provides a computer storage medium storing a program for a method based on leg-foot landing. When the program is executed, the steps of the method based on leg-foot landing are implemented.

[0136] In summary, an embodiment of the present invention provides a flying robot and method based on leg-foot landing, which introduces a rotatable propulsion device as the thrust for landing buffering, establishes a walking planning model based on a leg-foot robot based on a propeller, derives a dynamic equation containing a thrust term and performs linearization processing, uses the attenuated horizontal thrust to offset the inertial force generated by walking deceleration, and combines the gait time optimization method, uses the LQR control planner to obtain the center of mass horizontal trajectory that can track the desired zero-torque point trajectory, so that the robot can complete stable walking buffering at a higher forward speed, thereby enabling the robot to complete buffering and stop in a shorter time, solving the buffering problem of the flying robot landing at a higher initial velocity under limited terrain conditions; and also based on the landing buffering situation under non-zero forward speed, by optimizing the walking time, the leg-foot movement responds quickly to keep up with the center of mass speed, avoiding rapid deceleration and causing excessive inertia torque and falling, thereby ensuring the stability of the flying robot during landing.

[0137] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method based on leg-foot landing, characterized in that: include: Obtaining the forward velocity of the flying robot after landing, and obtaining a position sequence of the landing points of the flying robot according to the landing surface; Obtaining a gait time sequence and an expected zero-moment point trajectory of the flying robot based on the footfall position sequence and the forward velocity, and obtaining a foot-end motion trajectory of the flying robot based on a cycloid equation; calculating a horizontal thrust decay trajectory based on the forward velocity; Obtaining a center of mass horizontal trajectory according to the desired zero-moment point trajectory and the horizontal thrust attenuation trajectory; Calculating the center of mass height trajectory of the flying robot using a virtual ramp method based on the foothold position sequence and the center of mass horizontal trajectory; Performing inverse processing on the center of mass trajectory and the foot end motion trajectory to obtain a desired joint angle trajectory of the flying robot, wherein the center of mass trajectory is obtained based on the center of mass horizontal trajectory and the center of mass height trajectory; The flying robot performs a walking buffering motion based on the horizontal thrust attenuation trajectory and the desired joint angle trajectory, thereby achieving landing, including: the joint motors of the flying robot drive the flying robot to perform a walking motion according to the desired joint angle trajectory; the controller of the thrust device drives the front thruster and the rear thruster to generate corresponding thrust and drives the rotary motor to change the thrust direction according to the horizontal thrust attenuation trajectory and posture data generated by the posture sensor, thereby achieving buffering the inertial force generated by landing deceleration and ensuring the posture of the flying robot, thereby achieving landing; The flying robot comprises a thrust device, a flying robot body and a posture sensor, wherein the thrust device is arranged on the leg and foot mechanism of the flying robot body, the posture sensor is arranged on the flying robot body, the thrust device is used to generate forward thrust and backward thrust, and control the landing of the flying robot by controlling the magnitude of the forward thrust and backward thrust, the posture sensor is used to generate posture data of the flying robot and send the posture data to the thrust device, and the thrust device ensures the posture of the flying robot according to the posture data; the thrust device comprises: a rear thruster (1), a front thruster (2), a control mechanism and a connecting rod (4), the rear thruster (1) and the front thruster (2) are respectively connected to the two ends of the connecting rod (4) through a rotating pair; the control mechanism is connected to the middle position of the connecting rod (4), and the control mechanism is used to control the thrust direction and thrust magnitude generated by the rear thruster (1) and the front thruster (2); the control mechanism comprises: a rotating motor (3), a controller (5), a rocker arm, a first battery (6) and a second battery (7), the output of the rotating motor (3) The shaft is fixedly connected to the rocker arm, the rocker arm is rotatably connected to the connecting rod (4), and the rotating motor (3) drives the connecting rod (4) to rotate through the rocker arm, thereby controlling the rotation direction of the rear propeller (1) and the front propeller (2), and further controlling the thrust direction; the first signal output end of the controller (5) is connected to the signal input end of the rotating motor (3), and the second signal output end of the controller (5) is respectively connected to the signal input end of the rear propeller (1) and the signal input end of the front propeller (2), and the rotating motor (3) The invention relates to a vehicle control system comprising: a vehicle control system comprising: a first control signal sent by the controller (5), and a vehicle control system for controlling the rotation direction of the rear propeller (1) and the front propeller (2) according to the first control signal; a vehicle control system for controlling the rotation direction of the rear propeller (1) and the front propeller (2) according to the first control signal; a vehicle control system for controlling the rotation direction of the rear propeller (1) and the front propeller (2) according to the second ...

2. The leg-foot landing method according to claim 1, characterized in that: The step of obtaining the gait time sequence and the expected zero-moment point trajectory of the flying robot based on the foothold position sequence and the forward velocity specifically includes: Obtaining the step length of the gait cycle based on the footfall position sequence , step width Ji Bu Gao ; Calculate the gait time of the first step of the flying robot after landing according to the forward speed and the step length , the specific calculation method is as follows: in, is the step length, is the forward speed; Determine the gait time of the first step Is it greater than the minimum gait time? If it is greater than, then the gait time of the first step Calculate the gait time series as the benchmark; otherwise, use the minimum gait time The gait time series is calculated as the benchmark, and the gait time of any step in the gait cycle is satisfy ; Stride length according to gait cycle , step width , Bugao and the gait time series to generate an expected zero-moment point trajectory, the zero-moment point trajectory includes The zero moment point trajectory ZMPX and The zero moment point trajectory ZMPY in the direction.

3. The method according to claim 2, characterized in that: Stride length according to gait cycle , step width , Bugao The desired zero-moment point trajectory is generated from the gait time series, including assuming that the initial left foot landing point is , the right foot lands , then in During the gait cycle, calculate The expected zero moment point trajectory ZMPX in the direction is as follows: Among them, calculation The desired zero moment point trajectory ZMPY in the direction is as follows: 。 4. The leg-foot landing method according to claim 1, characterized in that: The calculating of the horizontal thrust attenuation trajectory based on the forward velocity specifically includes: The initial horizontal thrust is calculated based on the forward velocity as follows: in, is the minimum initial velocity requiring the use of thrust buffer, is the proportionality coefficient; Calculate the horizontal thrust attenuation trajectory based on the initial horizontal thrust : in, is the current time, , is the total time of horizontal thrust action.

5. The leg-foot landing method according to claim 1, characterized in that: The obtaining of the center of mass horizontal trajectory according to the expected zero-moment point trajectory and the horizontal thrust attenuation trajectory specifically includes: A walking planning model is constructed, and a zero-moment point equation is calculated based on the walking planning model. The zero-moment point equation is as follows: in, is the zero moment point of the flying robot, is the height of the center of mass, is the horizontal component of thrust, is the vertical component of thrust; Linearizing the zero-moment point equation to obtain a linear zero-moment point equation; A center-of-mass horizontal trajectory is obtained using an LQR planner based on the desired zero-moment point trajectory, the horizontal thrust attenuation trajectory, and the linear zero-moment point equation.

6. The leg-foot-based landing method according to claim 1, characterized in that: The method of calculating the center of mass height trajectory of the flying robot using a virtual slope method based on the foothold position sequence and the center of mass horizontal trajectory specifically includes: Obtaining the height position of the foothold according to the foothold position sequence; Connecting the height positions of the landing points to form a virtual slope; Calculate the slope of two adjacent footfall points, and calculate the center of mass height trajectory based on the slope and the horizontal center of mass trajectory. The calculation method is as follows: in, are the slopes of the two foot points, is the centroid height.

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