Flying robot and method based on leg-foot type landing

Abstract

The invention relates to the technical field of flying robots, and discloses a flying robot and method based on leg-foot type landing, and the method comprises the steps: obtaining the forward speed of the flying robot after landing, and obtaining a landing point position sequence according to the landing ground; acquiring a gait time sequence and an expected zero moment point track based on the landing point position sequence and the forward speed, and acquiring a foot end movement track; calculating a horizontal thrust attenuation trajectory according to the forward velocity; obtaining a horizontal centroid track according to the expected zero moment point track and the horizontal thrust attenuation track; calculating a centroid height trajectory based on the landing point position sequence and the centroid horizontal trajectory; an expected joint angle track is obtained based on the mass center track and the foot end movement track; and the flying robot carries out walking buffer motion based on the horizontal thrust attenuation trajectory and the expected joint angle trajectory so as to realize landing. According to the invention, the problem of landing of the flying robot at a relatively high forward speed under the condition of uneven terrain can be solved.

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 have strong aerial movement capabilities, and after completing their flight missions, they need to land on the ground. Therefore, it is very important that the flying robot can smoothly switch from aerial mode to land mode. The robot flies in the air at a certain forward speed. When it needs to land quickly at the destination, it needs to switch from aerial mode to land mode, that is, to land at a certain forward speed. The challenge faced by the robot is that it still has a certain initial velocity after landing. The robot needs to slow down and stop as soon as possible. The rapid deceleration of the robot will generate a large inertial force that will cause the robot to fall forward, which is a catastrophic consequence for the robot's transition from aerial mode to land mode. There are two main landing methods for aircraft at present. One is that multi-rotor aircraft land vertically by controlling the landing speed, but this landing method requires that the vertical speed before landing is close to zero, otherwise the aircraft will overturn because it cannot offset the residual kinetic energy after landing. In addition, this method consumes a lot of energy and the aircraft has poor maneuverability on the ground. The other landing method is that fixed-wing aircraft use wheeled tripods to glide over a long distance to complete the landing. Although this method uses wheels to glide to buffer the landing kinetic energy, its glide runway is long and has high requirements for the flatness of the ground. In addition, glide is a passive method to buffer the kinetic energy. These methods have their shortcomings and cannot meet the requirements of flying robots to land quickly and stably at a certain initial velocity under limited landing ground conditions. Current flying robots often use the following strategies when transitioning from aerial mode to land mode: 1) When landing in the air, the center of mass speed is reduced to zero, so that the robot speed is close to zero when landing. This method completes the deceleration when landing, and requires a long time and a large space to complete the 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 the 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

[0003] The primary purpose of the present invention is to overcome the problems existing in the prior art and to provide a flying robot and method based on leg-foot landing. The present invention can solve the problem of the flying robot landing at a high forward speed on uneven terrain and ensure the stability of the flying robot's posture.

[0004] In order to achieve the above-mentioned purpose, the present invention provides a thrust device, which includes: a rear thruster, a front thruster, a control mechanism and a connecting rod, wherein the rear thruster and the front thruster are respectively movably connected to the two ends of the connecting rod through a rotating pair; the control mechanism is connected to the middle position of the connecting rod, and the control mechanism is used to control the thrust direction and thrust size generated by the rear thruster and the front thruster.

[0005] The control mechanism includes: a rotating motor, a controller, a rocker arm, a first battery and a second battery, The output shaft of the rotary motor is fixedly connected to the rocker arm, the rocker arm is rotatably connected to the connecting rod, and the rotary motor drives the connecting rod to rotate through the rocker arm, thereby controlling the rotation direction of the rear propeller and the front propeller, and further controlling the thrust direction; The first signal output end of the controller is connected to the signal input end of the rotating motor, and the second signal output end of the controller is connected to the signal input end of the rear propeller and the signal input end of the front propeller respectively. The rotating motor receives a first control signal sent by the controller, and controls the rotation direction of the rear propeller and the front propeller according to the first control signal. The rear propeller and the front propeller receive a second signal sent by the controller, and change the thrust generated by the rear propeller and the front propeller according to the second signal. The first battery is used to power the rear thruster and the front thruster, and the second battery is used to power the controller.

[0006] In order to achieve the above-mentioned purpose, the present invention also provides a flying robot based on leg-foot landing, including the 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, 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.

[0007] In order to achieve the above object, the present invention further provides a method based on leg-foot landing, the method is based on a flying robot based on leg-foot landing, the method comprising: Acquire the forward speed of the flying robot after landing, and acquire the position sequence of the landing points of the flying robot according to the landing ground; Acquire 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 acquire the foot end motion trajectory of the flying robot based on the cycloid equation; calculating a horizontal thrust decay trajectory according to the forward velocity; Obtaining a center of mass horizontal trajectory according to the desired zero moment point trajectory and the horizontal thrust attenuation trajectory; Based on the foothold position sequence and the center of mass horizontal trajectory, a virtual ramp method is used to calculate the center of mass height trajectory of the flying robot; 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; The flying robot performs walking buffering motion based on the horizontal thrust attenuation trajectory and the expected joint angle trajectory, thereby achieving landing.

[0008] Furthermore, the acquiring of 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 specifically includes: Obtaining the step length of the gait cycle based on the footfall position sequence , Step Width Step High ; 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:

[0009] 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 satisfy ; According to the step length of the 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.

[0010] Furthermore, according to the step length of the gait cycle , Step Width , Bugao And the gait time series generates the expected zero moment point trajectory, including, assuming that the initial left foot landing point is , the right foot lands on , then in During the gait cycle, calculate The desired zero moment point trajectory ZMPX in the direction is as follows:

[0011] Among them, calculation The desired zero moment point trajectory ZMPY in the direction is as follows: .

[0012] Further, the calculating the horizontal thrust attenuation trajectory based on the forward speed specifically includes: The initial horizontal thrust is calculated based on the forward velocity, and the specific calculation method is as follows:

[0013] in, is the minimum initial velocity that requires the use of thrust cushioning, is the proportionality coefficient; Calculate the horizontal thrust decay trajectory based on the initial horizontal thrust :

[0014] in, is the current time, , is the total time of horizontal thrust action.

[0015] Further, obtaining 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:

[0016] in, is the zero moment point of the flying robot, is the centroid height, 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.

[0017] Furthermore, 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; The slope of two adjacent footfall points is calculated, and the center of mass height trajectory is calculated based on the slope and the horizontal center of mass trajectory, and the calculation method is as follows:

[0018] in, are the slopes of the two foot points, is the centroid height.

[0019] Furthermore, the flying robot performs walking buffering movement based on the horizontal thrust attenuation trajectory and the expected joint angle trajectory, thereby achieving landing, including: the joint motors of the flying robot drive the flying robot to perform walking movements according to the expected joint angle trajectory; the controller of the thrust device drives the front thruster and the rear thruster to generate corresponding thrust and drives the rotating motor to change the thrust direction according to the horizontal thrust attenuation trajectory and the posture data generated by the posture sensor, thereby achieving buffering of the inertial force generated by landing deceleration and ensuring the posture of the flying robot, thereby achieving landing.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. By introducing a rotatable propulsion device as the thrust for landing buffering, a walking planning model is established based on a leg-foot robot based on a propeller, and 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, and combined with 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 expected zero-torque point trajectory, so that the robot can complete stable walking buffering at a higher forward speed, so that the robot can 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; 2. According to the landing cushioning conditions at non-zero forward speed, the walking time is optimized to make the leg and foot movements respond quickly to keep up with the center of mass speed, avoiding rapid deceleration that causes excessive inertia torque and falls, and ensuring the stability of the flying robot when landing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1is a flow chart of a method based on leg-foot landing according to embodiment 2 of the present invention; Figure 2 is a structural diagram of a thrust device according to Embodiment 1 of the present invention; Figure 3 is the walking planning model of embodiment 2 of the present invention; Figure 4 Schematic diagram of walking buffering action in embodiment 2 of the present invention. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention is further described in detail below in conjunction with 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.

[0023] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0026] Example 1 A flying robot based on leg-foot landing according to an embodiment of the present invention includes: a thrust device, a flying robot body and a posture sensor, wherein 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, and 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.

[0027] Furthermore, the thrust device comprises: a rear thruster 1, a front thruster 2, a control mechanism and a connecting rod 4, wherein 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. Figure 2 .

[0028] Furthermore, the control mechanism includes: a rotating motor 3, a controller 5, a rocker arm, a first battery 6 and a second battery 7, 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; 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. The first battery 6 is used to supply power to the rear thruster 1 and the front thruster 2 , and the second battery 7 is used to supply power to the controller 5 .

[0029] 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 walking stability of the robot 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.

[0030] Example 2 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: Step S1: obtaining the forward speed of the flying robot after landing, and obtaining the position sequence of the landing points of the flying robot according to the landing ground; 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 and avoid 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.

[0031] 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; In a feasible embodiment, S2 specifically includes: Obtaining the step length of the gait cycle based on the sequence of footfall positions , Step Width Step High ; 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:

[0032] 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 for the benchmark, 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 sequence 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: , in: To satisfy the shortest time constraint, is the step length, It is the maximum linear velocity that the robot foot can achieve in the x direction.

[0033] Maximum gait time It can be calculated by the following formula: , in: is the minimum linear velocity that the robot foot can achieve in the x direction.

[0034] According to the step length of the 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 on , then in During the gait cycle, calculate The desired zero moment point trajectory ZMPX in the direction is as follows:

[0035] Among them, calculation The desired zero moment point trajectory ZMPY in the direction is as follows: .

[0036] Step S3: Calculate the horizontal thrust attenuation trajectory according to the forward speed; In a feasible embodiment, S3 specifically includes: The initial horizontal thrust is calculated based on the forward velocity as follows:

[0037] in, is the minimum initial velocity that requires the use of thrust cushioning, is the proportionality coefficient; Calculate the horizontal thrust decay trajectory based on the initial horizontal thrust :

[0038] in, is the current time, , is the total time of horizontal thrust action.

[0039] Step S4: obtaining a center of mass horizontal trajectory according to the desired zero moment point trajectory and the horizontal thrust attenuation trajectory; In a feasible embodiment, S4 includes: Figure 3 and Figure 4 As shown, a walking planning model is constructed. The model generates a torque acting on the center of mass according to the front and rear thrust difference or horizontal thrust to offset the inertia torque generated by the deceleration of the center of mass. Combining gait time optimization with the thrust-based gait buffering planning method, the robot center of mass trajectory planning at a higher forward speed can be achieved, and the robot can complete the buffering action and stop in a faster time. The walking speed buffering method based on the thrust inverted pendulum model is as follows: The two thrusters of the thrust device are arranged in front and behind its waist, that is, it 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.

[0040] According to the above model, when the robot is walking at a reduced speed, its zero torque point (i.e., the point) is subject to gravitational moment , the moment of inertia caused by the acceleration of the center of mass , the torque generated by the horizontal thrust And the vertical thrust torque , according to the definition of zero moment point, the sum of the moments of the robot at the zero moment point of its foot is zero:

[0041] in:

[0042] in:

[0043] is the horizontal component of thrust, is the vertical component of thrust; is the rotation angle of the thrust relative to the vertical direction.

[0044] The zero moment point of the robot in the x direction is is within the support polygon of the sole of the foot, then:

[0045] in, is the position of the heel in the x direction, is the toe position in the x direction.

[0046] According to the expressions of each moment, we can get:

[0047] 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. Stay within the support polygon.

[0048] Arrangement available With the center of mass state And thrust The relationship is:

[0049] From the above formula, we can know that the robot's landing walking motion 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 Too much change leads 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.

[0050] Linearizing the zero moment point equation to obtain a linear zero moment point equation; 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:

[0051] Based on the desired zero moment point trajectory, the horizontal thrust attenuation trajectory and the linear zero moment point equation, the LQR planner is used to obtain the center of mass horizontal trajectory. 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. :

[0052] in, For the horizontal thrust attenuation trajectory, the target zero torque point reference value As a feed-forward compensation term; Then, the cost function of the system is designed according to the LQR control theory:

[0053] 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:

[0054] Enter Substitute the state equation of the continuous system to obtain the horizontal center of mass trajectory, where the state equation is as follows:

[0055] Step S5: Based on the foothold 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; In a feasible embodiment, S5 specifically includes: obtaining the height position of the landing point according to the landing point position sequence; Connecting the height positions of the landing points to form a virtual slope; The slope of two adjacent footfall points is calculated, and the center of mass height trajectory is calculated based on the slope and the horizontal center of mass trajectory, and the calculation method is as follows:

[0056] 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 non-flat terrain.

[0057] 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; In a feasible embodiment, the center of mass trajectory (including the center of mass trajectories in three directions, namely, X, Y, and Z) is obtained by combining the center of mass horizontal trajectory and the center of mass height trajectory.

[0058] 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.

[0059] 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 rotating motor to change the thrust direction according to the horizontal thrust attenuation trajectory and the posture data generated by the posture sensor, so as to buffer the inertial force generated by the landing deceleration and ensure the posture of the flying robot, thereby achieving landing.

[0060] This embodiment introduces a rotatable propulsion device as the thrust for landing buffering, establishes a walking planning model according to a leg-foot robot based on a thruster, 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 center of mass horizontal trajectory that can track the expected zero-torque point trajectory, so that the robot can complete stable walking buffering at a higher forward speed, so that the robot can complete buffering and stop in a shorter time, and solve the buffering problem of the flying robot landing at a higher initial velocity under limited terrain conditions; according to the landing buffering situation at a non-zero forward speed, the walking time is optimized to make the leg-foot movement respond quickly to keep up with the center of mass speed, avoid falling due to excessive inertia torque caused by rapid deceleration, and ensure the stability of the flying robot when landing.

[0061] Example 3 An embodiment of the present invention further provides a computer storage medium on which is stored 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.

[0062] In summary, the embodiments of the present invention provide 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 according to the leg-foot robot based on the thruster, derives the dynamic equation containing the 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 expected zero torque point trajectory, so that the robot can complete stable walking buffering at a higher forward speed, so that the robot can complete buffering and stop in a shorter time, and solves the buffering problem of the flying robot landing at a higher initial velocity under limited terrain conditions; according to the landing buffering situation at a non-zero forward speed, the leg-foot movement is made to respond quickly to keep up with the center of mass speed by optimizing the walking time, so as to avoid falling due to excessive inertia torque caused by rapid deceleration, and ensure the stability of the flying robot during landing.

[0063] 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 thrust device, characterized in that: 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 movably connected to two ends of the connecting rod (4) via a rotary joint; 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).

2. A thrust device according to claim 1, characterized in that: 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 shaft of the rotating motor (3) 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 via 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); the rotating motor (3) receives a 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 a 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; The first battery (6) is used to supply power to the rear thruster (1) and the front thruster (2), and the second battery (7) is used to supply power to the controller (5).

3. A flying robot based on leg-foot landing, characterized in that: It comprises the thrust device, the flying robot body and the attitude sensor as described in any one of claims 1 to 2, the thrust device is arranged on the leg and foot mechanism of the flying robot body, the attitude 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 attitude sensor is used to generate attitude data of the flying robot and send the attitude data to the thrust device, and the thrust device ensures the attitude of the flying robot according to the attitude data.

4. A method based on leg-foot landing, the method is based on the flying robot based on leg-foot landing according to claim 3, characterized in that: include: Acquire the forward speed of the flying robot after landing, and acquire the position sequence of the landing points of the flying robot according to the landing ground; Acquire 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 acquire the foot end motion trajectory of the flying robot based on the cycloid equation; calculating a horizontal thrust decay trajectory according to the forward velocity; Obtaining a center of mass horizontal trajectory according to the desired zero moment point trajectory and the horizontal thrust attenuation trajectory; Based on the foothold position sequence and the center of mass horizontal trajectory, a virtual ramp method is used to calculate the center of mass height trajectory of the flying robot; 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; The flying robot performs walking buffering motion based on the horizontal thrust attenuation trajectory and the expected joint angle trajectory, thereby achieving landing.

5. A method based on leg-foot landing according to claim 4, characterized in that: The step of acquiring the gait time sequence and the expected zero-moment point trajectory of the flying robot based on the foot position sequence and the forward velocity specifically includes: Obtaining the step length of the gait cycle based on the footfall position sequence , Step Width Step High ; 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 satisfy ; According to the step length of the 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.

6. A method based on leg-foot landing according to claim 5, characterized in that: According to the step length of the gait cycle , Step Width , Bugao And the gait time series generates the expected zero moment point trajectory, including, assuming that the initial left foot landing point is , the right foot lands on , then in During the gait cycle, calculate The desired 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: 。 7. The method according to claim 4, characterized in that: The calculating of the horizontal thrust attenuation trajectory based on the forward speed specifically includes: The initial horizontal thrust is calculated based on the forward velocity, and the specific calculation method is as follows: in, is the minimum initial velocity that requires the use of thrust buffer, is the proportionality coefficient; Calculate the horizontal thrust decay trajectory based on the initial horizontal thrust : in, is the current time, , is the total time of horizontal thrust action.

8. The method according to claim 4, characterized in that: The step of obtaining the horizontal trajectory of the center of mass 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 centroid height, 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.

9. A leg-foot-based landing method according to claim 4, characterized in that: The step 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; The slope of two adjacent footfall points is calculated, and the center of mass height trajectory is calculated based on the slope and the horizontal center of mass trajectory, and the calculation method is as follows: in, are the slopes of the two foot points, is the centroid height.

10. According to the claim Any one of the leg-foot landing methods described above is characterized in that: The flying robot performs walking buffering movement based on the horizontal thrust attenuation trajectory and the expected joint angle trajectory to achieve landing, including: the joint motor of the flying robot drives the flying robot to perform walking movements according to the expected joint angle trajectory; the controller of the thrust device drives the front thruster and the rear thruster to generate corresponding thrust and drives the rotating motor to change the thrust direction according to the horizontal thrust attenuation trajectory and the posture data generated by the posture sensor, so as to buffer the inertial force generated by the landing deceleration and ensure the posture of the flying robot, thereby achieving landing.

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