Gait control method and device of foot-type robot and foot-type robot

Abstract

The invention relates to the technical field of robots, and discloses a gait control method and device of a foot-type robot and the foot-type robot, and the method comprises the steps that legs of the foot-type robot are controlled through a preset gait sequence, and the gait sequence comprises a swinging phase and a supporting phase; in the current control period, if it is not detected that the first leg touches the ground under the condition that the first leg of the foot type robot is currently in a swing phase, N ground touch delay control periods are added after the last control period of the swing phase of a gait sequence corresponding to the first leg, and a first gait sequence is generated; the delay grounding control period is in a swing phase, and N is greater than or equal to 2; and issuing the first gait sequence so as to control the first leg according to the first gait sequence in a subsequent control period. According to the invention, the gait sequence of the mechanical leg is delayed, so that the mechanical leg is always in a swing phase before touching the ground and can walk on a rugged ground.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and in particular to a gait control method and device for a legged robot and the legged robot. Background Art

[0002] A legged robot has multiple (eg, two, four, etc.) mechanical legs. By controlling the gait of each mechanical leg, each mechanical leg of the legged robot switches back and forth between a support phase and a swing phase, thereby controlling the movement of the legged robot.

[0003] When the ground is flat, the control effect of the legged robot is better; but in reality, there are often rugged ground. When the legged robot walks on the rugged ground, one or some of the mechanical legs may have the problem of delayed touching the ground, which affects the control effect of the legged robot.

[0004] In addition, the time of touching the ground can generally be delayed through visual prediction and other methods, but the ground information obtained by the visual sensor has errors, resulting in the ground height information obtained by the robot not being completely consistent with the actual information. The robot's gait may be switched before its legs touch the ground, causing the robot's legs to shake and other phenomena. Summary of the invention

[0005] In view of this, the present invention provides a gait control method and device for a legged robot and a legged robot to solve the problem of unstable control when the legged robot touches the ground with delay.

[0006] In a first aspect, the present invention provides a gait control method for a legged robot, comprising:

[0007] Controlling the legs of the footed robot by a preset gait sequence, wherein the gait sequence includes a swing phase and a stance phase;

[0008] In the current control cycle, when the first leg of the legged robot is currently in the swing phase, if the first leg is not detected to be touching the ground, after the last control cycle of the swing phase of the gait sequence corresponding to the first leg, N delayed touchdown control cycles are added to generate the first gait sequence; the delayed touchdown control cycle is in the swing phase, and N ≥ 2;

[0009] The first step sequence is issued to control the first leg according to the first step sequence in a subsequent control cycle.

[0010] In some optional implementations, the control amount of the first leg in the delayed touchdown control period is used to:

[0011] The horizontal position of the first leg in the horizontal plane is controlled to remain unchanged, and the horizontal speed is zero; and the vertical speed of the first leg in the vertical direction is controlled to be a preset speed, and the vertical position of the first leg in the vertical direction is determined based on the time integral of the vertical speed.

[0012] In some optional embodiments, the control amount of the first leg includes:

[0013]

[0014] and,

[0015] in, represents the position control amount of the first leg on the horizontal plane X-axis during the delayed touchdown control period, represents the horizontal position of the first leg on the X-axis of the horizontal plane determined in the previous control cycle; represents the position control amount of the first leg on the Y-axis of the horizontal plane during the delayed touchdown control period, represents the horizontal position of the first leg on the Y-axis of the horizontal plane determined in the previous control cycle; represents the speed control amount of the first leg on the horizontal plane X-axis during the delayed touchdown control period, represents the speed control amount of the first leg on the Y-axis of the horizontal plane during the delayed touchdown control period;

[0016] represents a speed control amount of the first leg in the vertical direction during the delayed touchdown control period; Indicates the preset speed; represents the position control amount of the first leg in the vertical direction during the delayed contact control period, represents the vertical position of the first leg in the vertical direction determined in the previous control cycle, t cycle Indicates the duration of the control cycle.

[0017] In some optional embodiments, the legged robot is a quadruped robot;

[0018] In the delayed touchdown control period, the height control amount of the legged robot is used to: determine the body descent speed of the legged robot according to the number of delayed touchdown mechanical legs, and adjust the height of the legged robot according to the body descent speed;

[0019] The pitch angle control amount of the footed robot is used to: when the first leg is the front leg and the hind leg does not touch the ground with delay, control the pitch angle of the footed robot to increase; when the first leg is the hind leg and the front leg does not touch the ground with delay, control the pitch angle of the footed robot to decrease.

[0020] In some optional embodiments,

[0021] in, represents the height control amount of the legged robot, represents the height of the legged robot determined in the previous control cycle, w i represents the weight of the i-th robotic leg, and when the i-th robotic leg does not touch the ground late, represents the preset speed, t cycle Indicates the duration of the control cycle; w pitch Indicates the pitch angle weight.

[0022] In some optional embodiments, the method further comprises:

[0023] In the current control cycle, when the first leg of the footed robot is currently in the swing phase, if the first leg is not detected to be touching the ground, for the second leg coordinated with the first leg, after the last control cycle of the support phase of the gait sequence corresponding to the second leg, N delayed support control cycles are added to generate a second gait sequence; the delayed support control cycle is in the support phase;

[0024] The second gait sequence is issued to control the second leg according to the second gait sequence in a subsequent control cycle.

[0025] In some optional embodiments, the method further comprises:

[0026] In the current control cycle, if it is detected that the first leg touches the ground, a transition control cycle is set at the initial position of the gait sequence corresponding to the first leg to generate a third gait sequence; the transition control cycle is a control cycle in a swing phase and used for state switching;

[0027] The third gait sequence is released.

[0028] In some optional implementations, setting a transition control period at an initial position of a gait sequence corresponding to the first leg includes:

[0029] When the first control cycle of the gait sequence corresponding to the first leg is in the swing phase, a transition control cycle is set at the initial position of the gait sequence corresponding to the first leg, and each control cycle in the swing phase after the transition control cycle is updated to an early ground contact control cycle in the stance phase;

[0030] When the first control cycle of the transition control cycle is in the stance phase, the transition control cycle is set at the initial position of the gait sequence corresponding to the first leg, and other control cycles are kept unchanged.

[0031] In a second aspect, the present invention provides a gait control device for a legged robot, comprising:

[0032] A gait module, for controlling the legs of the footed robot through a preset gait sequence, wherein the gait sequence includes a swing phase and a stance phase;

[0033] A processing module, configured to, in a current control cycle, when the first leg of the legged robot is currently in a swing phase, if the first leg is not detected to have touched the ground, add N delayed touchdown control cycles after the last control cycle of the swing phase of a gait sequence corresponding to the first leg to generate a first gait sequence; the delayed touchdown control cycle is in the swing phase, and N ≥ 2;

[0034] A publishing module is used to publish the first step sequence so as to control the first leg according to the first step sequence in a subsequent control cycle.

[0035] In a third aspect, the present invention provides a legged robot, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the gait control method of the legged robot according to the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0036] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the gait control method for a legged robot according to the first aspect or any corresponding embodiment thereof.

[0037] In a fifth aspect, the present invention provides a computer program product, comprising computer instructions for causing a computer to execute the gait control method for a legged robot according to the first aspect or any corresponding embodiment thereof.

[0038] The present invention predicts the gait sequence of the mechanical legs through the traditional prediction method, determines the mode gait sequence, and adds N control cycles representing delayed touchdown to the mode gait sequence when the mechanical legs are not detected touching the ground, thereby delaying the gait sequence of the mechanical legs, so that the mechanical legs are always in the swing phase before touching the ground, and can be controlled accordingly when the mechanical legs are delayed in touching the ground. When the legged robot is located on rough ground, it can also walk relatively stably, and can be applied to a variety of ground scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 This is a schematic diagram of a trotting gait of a quadruped robot;

[0041] Figure 2 is a schematic flow chart of a gait control method for a legged robot according to an embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of generating a first step state sequence according to an embodiment of the present invention;

[0043] Figure 4 is a flow chart of another gait control method of a legged robot according to an embodiment of the present invention;

[0044] Figure 5 is a schematic diagram of a gait sequence during delayed ground contact according to an embodiment of the present invention;

[0045] Figure 6 is a detailed processing diagram of a reference period according to an embodiment of the present invention;

[0046] Figure 7 is a schematic diagram of generating a second gait sequence according to an embodiment of the present invention;

[0047] Figure 8 is a schematic diagram of processing when early touchdown occurs according to an embodiment of the present invention;

[0048] Fig. 9 is a structural block diagram of a gait control device for a legged robot according to an embodiment of the present invention;

[0049] Fig.10 Schematic diagram of the hardware structure of the legged robot according to an embodiment of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0051] At present, the gait planning of legged robots is mainly based on the classic MPC (Model Predictive Control), which includes CMPC (Constrained MPC), NMPC (Nonlinear MPC), etc. Its gait planning and optimization sequence are designed based on fixed gait sequences. Ideal results can be achieved on level ground and in scenes with high-precision visual maps. However, the ground in most scenes is uneven, and the map also depends on the effect of sensors and mapping solutions. In the case of rugged ground and possible map errors, the MPC control method has poor adaptability and is difficult to deal with the problem of delayed touchdown.

[0052] Gait Schedule refers to a predefined sequence of leg lifting or landing, which includes two phases: swing phase and support phase in one cycle of gait sequence. Among them, swing phase and support phase are two phases in the gait cycle, which are usually divided by time. A complete gait cycle includes support phase and swing phase. For example, in a bipedal robot, the support phase usually accounts for 60% of the gait cycle, while the swing phase accounts for 40%. In a quadruped robot, the specific division of the gait cycle varies according to the gait type (such as diagonal gait, trotting gait, etc.).

[0053] Specifically, the support phase refers to the stage when the robot's legs are in contact with the ground and provide support force. This leg is called the support leg. In this stage, the support leg needs to stably support the body to ensure that the center of mass moves along the desired trajectory. The swing phase refers to the stage when the robot's legs leave the ground and swing to the next support point along a predetermined trajectory. This leg is called the swing leg. In this stage, the motion trajectory of the swing leg is usually planned by a control algorithm.

[0054] Take the trot gait as an example. Figure 1 Figure 2 shows a schematic diagram of a trotting gait of a quadruped robot. Figure 1 As shown in Figure 2, under normal circumstances, the trotting gait of the quadruped robot is as follows: Figure 1 The normal trotting gait shown in the upper part is shown, but this normal trotting gait is only applicable to flat ground, or in other words, it is an ideal trotting gait. In actual situations, due to the uneven ground, the trotting gait of the quadruped robot may be Figure 1 The actual trotting gait shown in the lower half.

[0055] like Figure 1 As shown in FIG. 1 , in actual situations, leg 1 does not touch the ground for a long time, that is, delayed touching the ground; while leg 3 touches the ground in advance. In this case, since leg 1 touches the ground late, but leg 2 switches normally from the support phase (touching the ground) to the swing phase (not touching the ground), that is, leg 1 and Figure 2At the same time, the legged robot does not touch the ground, making it unstable when walking.

[0056] To address the problem of delayed touchdown, the touchdown time can be delayed through visual prediction and other methods, but this method is limited by visual errors, resulting in inaccurate delays.

[0057] The gait control method of a legged robot provided in an embodiment of the present invention delays the gait sequence of the mechanical legs by adding multiple control cycles representing delayed ground contact to the gait sequence of the mechanical legs, and combines ground contact detection to trigger state switching, so that the mechanical legs with delayed ground contact can be controlled when the delayed ground contact occurs, and can adapt to a variety of ground surfaces.

[0058] According to an embodiment of the present invention, an embodiment of a gait control method for a legged robot is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0059] In this embodiment, a gait control method for a legged robot is provided, which can be applied to a controller of the legged robot. The controller can be located in the legged robot itself or in a controller located on the network side. Figure 2 is a flow chart of a gait control method for a legged robot according to an embodiment of the present invention. Figure 2 As shown, the process includes the following steps.

[0060] Step S201 : controlling the legs of the footed robot through a preset gait sequence, where the gait sequence includes a swing phase and a support phase.

[0061] In this embodiment, the gait sequence of each leg of the legged robot can be predefined, and each gait cycle of the gait sequence includes a swing phase and a support phase. Among them, each gait cycle is further divided into multiple control cycles, for example, one control cycle is 20ms, and the gait planning of the legged robot can be performed based on the MPC (model predictive control) method. Then, in each control cycle, the control strategy of each mechanical leg of the legged robot can be predicted. For example, the preset gait sequence is a mode gait sequence (ModeSchedule). For example, the mode gait sequence can be determined based on OCS2 (Optimal Control Toolbox for Switched Systems, a toolbox specifically used to solve the optimal control problem of switching systems).

[0062] Step S202, in the current control cycle, when the first leg of the footed robot is currently in the swing phase, if the first leg is not detected touching the ground, after the last control cycle of the swing phase of the gait sequence corresponding to the first leg, N delayed touchdown control cycles are added to generate the first gait sequence; the delayed touchdown control cycle is in the swing phase, and N≥2.

[0063] The method provided in this embodiment can be executed for each mechanical leg of the legged robot. Taking the current control cycle (ie, the control cycle corresponding to the current moment) as an example, a mechanical leg of the legged robot is taken as a controlled target and is called the first leg.

[0064] In the current control cycle, the gait sequence corresponding to the first leg can represent the state of the first leg in the subsequent control cycle. In addition, in the current control cycle, based on the current state of the first leg, corresponding processing is performed, and the state of the first leg can specifically be a swing phase or a support phase. Among them, the current state of the first leg can be determined by a predetermined gait sequence. It can be understood that at the very beginning, generally, each mechanical leg of the footed robot is touching the ground, that is, each mechanical leg is initially in the support phase.

[0065] In this embodiment, in each control cycle including the current control cycle, each mechanical leg of the legged robot may be subjected to ground contact detection to determine whether the mechanical leg touches the ground in the control cycle. Whether the mechanical leg touches the ground may be detected by the control current of the mechanical leg or by a leg sensor, and this embodiment does not limit the means of ground contact detection.

[0066] Specifically, in the current control cycle, if the first leg is currently in the swing phase and the first leg is not detected to have touched the ground, it means that in the current control cycle, the first leg may not have reached the touchdown point according to the normal gait, or the first leg may have delayed touching the ground. In order to deal with the delayed touchdown situation in the future, N new control cycles are added to the gait sequence corresponding to the first leg. In this embodiment, the control cycle is called the delayed touchdown control cycle, thereby obtaining a new gait sequence, that is, the first gait sequence.

[0067] Among them, for the gait sequence corresponding to the first leg, N delayed touchdown control cycles are added after the last control cycle of the swing phase of the gait sequence to obtain the first gait sequence; if the gait sequence includes multiple swing phases, N delayed touchdown control cycles are added at the end of the first swing phase.

[0068] For the first step sequence, the first leg can be controlled based on the first step sequence in each subsequent control cycle; when the current control cycle reaches the delayed touchdown control cycle, a new delayed touchdown control cycle is added after the last delayed touchdown control cycle in the first step sequence to update the first step sequence, so that the first step sequence always includes at least N delayed touchdown control cycles, thereby realizing the rolling (Roll) of the first step sequence. Alternatively, the above step S202 is performed in each control cycle. If the current control cycle is the previously set delayed touchdown control cycle, the rolling (Roll) of the gait sequence can also be realized by adding N delayed touchdown control cycles. For the convenience of description, the gait sequence with such rolling and adding control cycles can be called a rolling gait sequence (RollSchedule).

[0069] Furthermore, N≥2, that is, at least two delayed touchdown control cycles are added. If only one delayed touchdown control cycle is added, when the delayed touchdown control cycle is reached at the current moment (that is, the current control cycle is the delayed touchdown control cycle), if the touchdown is still not detected at this time, it will result in a lack of time to update in the next control cycle, and the delayed touchdown situation cannot be dealt with. Setting N to not less than 2 can ensure that there are additional control cycles for sequence updates; in general, N=2 is sufficient.

[0070] Figure 3 A schematic diagram of generating the first step sequence is shown in FIG. Figure 3 As shown, a pattern gait sequence of a certain range (Horizon) can be predefined, which includes multiple control cycles; Figure 3 Taking the duration of the control cycle dt = 20ms (milliseconds) as an example, the mode gait sequence corresponds to 50 control cycles, and its range is 1s. Moreover, taking the current moment as 0s as an example, at the current moment, the first 20 control cycles of the mode gait sequence are all swing phases (0s to 0.4s), the middle 20 control cycles are all support phases (0.4s to 0.8s), and the last 10 control cycles are switched to the swing phase (0.8s to 1s).

[0071] In the current control cycle corresponding to the current moment, the first leg is currently in the swing phase, then Figure 3 The pattern gait sequence shown can represent the gait sequence corresponding to the first leg. For the convenience of description, it is called the first pattern gait sequence. Moreover, if the first leg is not detected touching the ground, two (i.e., N=2) delayed touchdown control cycles are added to the first pattern gait sequence, that is, two dts can be delayed, which correspond to the two control cycles of 0.4s-0.42s and 0.42s-0.44s, and finally the first step sequence is obtained. Among them, the first step sequence is specifically called the first rolling gait sequence, which can be specifically as follows Figure 3After adding N control cycles, the range of the gait sequence can remain unchanged, or the corresponding control cycle can be increased (such as Figure 3 As shown, the range of the first rolling gait sequence is 1.04s, that is, two dt are added), which is not limited in this embodiment.

[0072] The delayed touchdown control cycle is a control sequence in the swing phase, such as Figure 3 As shown, the control cycle of the swing phase in the gait sequence can be delayed, triggering the gait sequence to roll backward, so that the first leg (i.e., the swing leg) in the swing phase remains in the swing phase before it touches the ground, thereby being able to cope with the scenario of delayed touchdown.

[0073] In some optional embodiments, the above step S202 of "adding N delayed touchdown control cycles after the last control cycle of the swing phase of the gait sequence corresponding to the first leg" may include step A1 and step A2.

[0074] Step A1, when the first control cycle of the first mode gait sequence (i.e., the gait sequence corresponding to the first leg) is in the swing phase, N delayed touchdown control cycles are added to the last position of the swing subsequence in the first mode gait sequence; the swing subsequence is a sequence corresponding to continuous control cycles in the swing phase and includes the first control cycle of the first mode gait sequence.

[0075] Step A2: when the first control cycle of the first mode gait sequence is in the stance phase, N delayed touchdown control cycles are added to the initial position of the first mode gait sequence.

[0076] In this embodiment, the delayed touchdown control period corresponds to the delayed touchdown situation. After the delayed touchdown, the phase will be switched to the stance phase. Therefore, the delayed touchdown control period needs to be set before the phase is switched to the stance phase. When the first leg is currently in the swing phase, the first control period of the first mode gait sequence may be the swing phase or the stance phase. For different situations, the position of the delayed touchdown control period is adaptively set.

[0077] Specifically, if the first control cycle of the first mode gait sequence is in the swing phase, such as Figure 3 As shown in , the first control cycle (0s-0.02s) is the swing phase, indicating that after the current moment there is a sequence corresponding to the continuous control cycles in the swing phase, namely the swing subsequence, as shown in Figure 3 The sequence corresponding to the 20 consecutive control cycles corresponding to 0s to 0.4s in the swing subsequence. After the swing subsequence, it will switch to the support phase. In this embodiment, N delayed touchdown control cycles are added at the last position of the swing subsequence, so that multiple additional delayed touchdown control cycles can be set before switching to the support phase. Figure 3As shown, two delayed touchdown control cycles corresponding to 0.4s-0.42s and 0.42s-0.44s are added.

[0078] If the delayed touchdown control period is about to arrive at the current moment, the first control period of the first mode gait sequence is the stance phase, and the control period is, for example, Figure 3 In this case, N delayed touchdown control cycles are added to the initial position of the first mode gait sequence, that is, N additional delayed touchdown control cycles are set before switching to the stance phase.

[0079] Generally, N delayed touchdown control cycles are added in advance, that is, they are mainly implemented based on step A1.

[0080] Step S203, issuing the first posture sequence, so as to control the first leg according to the first posture sequence in the subsequent control cycle.

[0081] In this embodiment, after the first step sequence is obtained, the first step sequence is published, so that the first leg can be controlled according to the first step sequence in other control cycles after the current control cycle (for example, the next control cycle after the current control cycle). This can be repeated to achieve rolling of the gait sequence, ensuring that there is always a delayed touchdown control cycle before the touchdown is detected.

[0082] The gait control method of a legged robot provided in an embodiment of the present invention predicts the gait sequence of the mechanical legs through a traditional prediction method, determines a pattern gait sequence, and adds N control cycles representing delayed touchdown to the pattern gait sequence when the mechanical legs are not detected touching the ground, thereby delaying the gait sequence of the mechanical legs, so that the mechanical legs are always in a swinging phase before touching the ground, and can be controlled accordingly when the mechanical legs are delayed in touching the ground. When the legged robot is on rough ground, it can also walk relatively stably, and can be applied to a variety of ground scenarios.

[0083] In this embodiment, another gait control method for a legged robot is provided, which can be applied to a controller of the legged robot. The controller can be located in the legged robot itself or in a network side. Figure 4 is a flow chart of a gait control method for a legged robot according to an embodiment of the present invention. Figure 4 As shown, the process includes the following steps.

[0084] Step S401 : controlling the legs of the footed robot through a preset gait sequence, where the gait sequence includes a swing phase and a support phase.

[0085] See Figure 2 The relevant description of step S201 of the illustrated embodiment will not be repeated here.

[0086] Step S402, in the current control cycle, when the first leg of the footed robot is currently in the swing phase, if the first leg is not detected touching the ground, after the last control cycle of the swing phase of the gait sequence corresponding to the first leg, N delayed touchdown control cycles are added to generate the first gait sequence; the delayed touchdown control cycle is in the swing phase, and N≥2.

[0087] See Figure 2 The relevant description of step S202 of the illustrated embodiment will not be repeated here.

[0088] In some optional embodiments, within each delayed touchdown control cycle, a control amount is adaptively set to control the first leg, and the control amount is specifically used to: control the horizontal position of the first leg in the horizontal plane to remain unchanged and the horizontal speed to be zero; and control the vertical speed of the first leg in the vertical direction to be a preset speed, and determine the vertical position of the first leg in the vertical direction based on the time integral of the vertical speed.

[0089] In this embodiment, if the delayed touchdown control period is reached at the current moment, it means that the first leg should have switched to the stance phase at this moment, but due to the depression at the touchdown point below the first leg, the touchdown is not detected, i.e., delayed touchdown. In this case, the horizontal speed of the first leg on the horizontal plane is controlled to be zero, so that the horizontal position of the horizontal plane remains unchanged; at the same time, a certain preset speed is set for the first leg in the vertical direction, that is, the vertical speed of the first leg is set to the preset speed, and accordingly, the vertical position of the first leg in the vertical direction can be determined based on the time integral of the vertical speed.

[0090] Optionally, the control amount of the first leg includes a position control amount and a speed control amount. Specifically, the control amount of the first leg includes:

[0091]

[0092] and,

[0093] in, It represents the position control amount of the first leg on the horizontal X-axis in the delayed touchdown control cycle. represents the horizontal position of the first leg on the horizontal plane X-axis determined in the previous control cycle (the previous control cycle of the delayed touchdown control cycle), that is, the final determined position; It represents the position control amount of the first leg on the Y-axis of the horizontal plane in the delayed touchdown control cycle. represents the horizontal position of the first leg on the Y-axis of the horizontal plane determined in the previous control cycle; It represents the speed control amount of the first leg on the horizontal plane X axis in the delayed touchdown control cycle, It represents the speed control amount of the first leg on the Y-axis of the horizontal plane in the delayed touchdown control period.

[0094] It represents the speed control amount of the first leg in the vertical direction during the delayed touchdown control period; Indicates preset speed and pre-set speed; It represents the vertical position control amount of the first leg in the delayed touchdown control cycle. represents the vertical position of the first leg in the vertical direction determined in the previous control cycle, t cycle Indicates the duration of the control cycle, such as 20ms. In the above formula, d in the upper right corner indicates the expected value.

[0095] In this embodiment, the plane where the X-axis and Y-axis are located is the horizontal plane, and the Z-axis is the vertical direction. By setting the preset speed The delayed ground contact control of the first leg can be realized, and the control amount of the first leg can control the first leg to probe downward at a uniform speed, so as to detect in real time whether it touches the ground, and the implementation method is simple.

[0096] Optionally, the legged robot is a quadruped robot. In addition, during the delayed touchdown control period, the height control amount of the legged robot is used to: determine the body descent speed of the legged robot according to the number of delayed touchdown mechanical legs, and adjust the height of the legged robot according to the body descent speed.

[0097] The pitch angle control amount of the legged robot is used to: when the first leg is the front leg and the rear leg does not touch the ground with delay, control the pitch angle of the legged robot to increase; when the first leg is the rear leg and the front leg does not touch the ground with delay, control the pitch angle of the legged robot to decrease.

[0098] Optionally, the height control amount and the pitch angle control amount are respectively:

[0099]

[0100] in, It represents the height control amount of the legged robot, which is the height control amount when delayed contact (LateContact). represents the height of the legged robot determined in the previous control cycle (the previous control cycle of the delayed touchdown control cycle), which is the height of the robot body, w i represents the weight of the i-th robotic leg, and when the i-th robotic leg does not touch the ground late, w i =0, Indicates the preset speed, t cycle Indicates the duration of the control cycle; w pitch Indicates the pitch weight.

[0101] In this embodiment, for a quadruped robot, two mechanical legs are generally in the swing phase by default when it moves. If there is a delay in touching the ground, the height of the legged robot needs to be adjusted down synchronously to avoid the situation where the mechanical legs cannot touch the ground even when they are straightened when the ground is particularly uneven. The more mechanical legs that delay touching the ground, the faster the body descends.

[0102] As shown in the above formula, set the corresponding weight w for each mechanical leg i , if the robot leg does not touch the ground later, then w i =0; if the robot leg touches the ground later, its weight w i is the preset value. For example, the weight w i Set to 0.5. When only one robot leg touches the ground with delay, ∑w i =0.5, that is, at this time, the preset speed When both mechanical legs touch the ground with delay, ∑w i =1, that is, the descent speed at this time is the preset speed

[0103] Furthermore, if the duration of delayed touchdown of the front and rear legs is different, the pitch angle is adjusted accordingly. The pitch angle, as the name implies, is the angle of "pitch" of the aircraft relative to the XOY plane of the inertial coordinate system. The adjustment principle is: when the front leg touches the ground, the pitch of the rear leg is reduced, and when the rear leg touches the ground, the pitch of the front leg is increased. When the aircraft body is tilted downward, the pitch angle is positive; when the aircraft body is tilted upward, the pitch angle is negative.

[0104] If the first leg is the front leg (delayed touchdown) and the rear leg does not touchdown, the head needs to be lowered and the pitch angle increases, so the pitch angle weight w pitch On the contrary, if the first leg is the back leg (delayed touchdown) and the front leg does not delay touchdown, the head needs to be tilted up, and the pitch angle decreases, so the pitch angle weight w pitch Can be negative.

[0105] In this embodiment, when delayed touchdown occurs, the body height and pitch angle of the legged robot are adaptively adjusted so that the legged robot as a whole can cope with the delayed touchdown situation and ensure stable movement.

[0106] Step S403: issuing a first state sequence. The first state sequence is used to control the first leg according to the first state sequence in the subsequent control cycle.

[0107] See Figure 2 The relevant description of step S203 of the illustrated embodiment will not be repeated here.

[0108] Step S404, within the current control cycle, if it is detected that the first leg touches the ground, a transition control cycle is set at the initial position of the gait sequence corresponding to the first leg to generate a third gait sequence; the transition control cycle is a control cycle in the swing phase and is used for state switching.

[0109] Step S405: issuing the third gait sequence, so that the state can be switched in the next control cycle according to the control amount of the transition control cycle.

[0110] In this embodiment, if the first leg touches the ground is not detected in the current control cycle, as shown in step S402, the gait sequence is continuously updated to ensure that the first gait sequence has at least two delayed touchdown control cycles. If the first leg touches the ground is detected in the current control cycle, the swing phase can be switched to the stance phase; since the state switching requires a certain amount of time to process, this embodiment sets a transition control cycle for this situation to enable the state switching.

[0111] Specifically, if the first leg touches the ground, a transition control period is set at the initial position of the gait sequence corresponding to the first leg (such as the first mode gait sequence). Generally, only one transition control period needs to be added to generate a new gait sequence; for ease of description, it is referred to as the third gait sequence. When setting the transition control period, an additional control period can be added, or the original control period can be adjusted to the transition control period, which is not limited in this embodiment.

[0112] by Figure 3 Taking the first step sequence as an example, if the current moment is before the delayed touchdown control period, the processing logic is similar to the above steps and can ensure that two control periods are delayed. When the current moment reaches the delayed touchdown control period, the corresponding processing can also be performed on whether the first leg touches the ground.

[0113] Figure 5 A schematic diagram of a gait sequence with delayed ground contact is shown. Figure 3 Based on the gait sequence shown in , if the current time reaches 0.4s and the first leg has not touched the ground, a delayed touchdown occurs at this time, and the first step sequence generated is as follows Figure 5 As shown, the initial 0.4s-0.42s and the initial 0.42s-0.44s are both delayed touchdown control cycles.

[0114] To facilitate the description of the delayed touchdown process, Figure 5 As shown, a partial period related to the delayed touchdown control cycle is used as a reference period 501. Figure 5 In the example, the reference time period 501 corresponds to 0.38s to 0.48s.

[0115] Figure 6FIG. 5 shows a detailed processing diagram of the reference period 501. Figure 6 As shown, in each control cycle (20ms), it is possible to detect at high frequency whether the mechanical leg touches the ground. Figure 6 The touchdown detection is performed based on WBC (Whole Body Control), and the detection period is 2ms, that is, WBC dt = 2ms. If the current moment reaches the control period corresponding to 0.4s to 0.42s (previously determined to be the delayed touchdown control period), the touchdown detection can be performed in real time within the control period (0.4s to 0.42s).

[0116] like Figure 6 As shown in the figure, if the first leg touches the ground within the control cycle (0.4s-0.42s), two delayed touchdown control cycles are added to the gait sequence, corresponding to the two control cycles of 0.42s-0.44s and 0.44s-0.46s. This is equivalent to moving back one control cycle (0.44s-0.46s) on the basis of the rolling gait sequence determined in the previous control cycle, thereby realizing the rolling of the gait sequence.

[0117] If the first leg touches the ground within the control period (0.4s to 0.42s), since MPC needs a certain amount of time to calculate the gait sequence, a transition control period for gait switching is set in this case, such as Figure 6 As shown, the transition control period is the first control period thereafter, that is, the control period corresponding to 0.42s to 0.44s, and the gait sequence generated at this time is called the third gait sequence. When the transition control period is reached at the current moment, the state can be switched from the swing phase to the support phase.

[0118] The gait control method of the legged robot provided in this embodiment utilizes the means of touchdown detection, and reconstructs the gait sequence and foothold planning by delaying the touchdown of the swing leg to trigger the gait sequence to roll backward, and allows the supporting leg to be in the supporting leg state before the swing leg touches the ground, and the swing leg with delayed touchdown can change the foothold position based on the velocity integral; all delayed touchdowns are switched in state by the mechanism triggered by touchdown detection during this rolling, thereby solving the problem that the MPC algorithm cannot handle delayed touchdowns. In addition, the advance amount of the rolling is greater than or equal to 2 times the MPC iterative control cycle, which can ensure that there are enough control cycles for data processing.

[0119] In some optional embodiments, multiple legs in a legged robot cooperate with each other to achieve movement. Under normal circumstances, when a mechanical leg is in the swinging phase, the other mechanical leg that cooperates with it is in the supporting phase; for example, for a quadruped robot, its left front leg and right hind leg can be coordinated, and its right front leg and left hind leg can be coordinated; among which, which specific two legs cooperate is also related to the control method, and this embodiment does not limit this.

[0120] In this embodiment, when determining the gait sequence of the first leg, the gait sequence of the other legs cooperating with it is also determined synchronously. For ease of description, the other legs cooperating with the first leg are referred to as the second leg. The method also includes the following steps B1 to B2.

[0121] Step B1, in the current control cycle, when the first leg of the footed robot is currently in the swing phase, if the first leg is not detected touching the ground, for the second leg coordinated with the first leg, after the last control cycle of the support phase of the gait sequence corresponding to the second leg, N delayed support control cycles are added to generate a second gait sequence; the delayed support control cycle is in the support phase.

[0122] Step B2, issuing the second gait sequence to control the second leg according to the second gait sequence in the subsequent control cycle.

[0123] In this embodiment, when N delayed touchdown control cycles are added to the first leg, N delayed support control cycles are also added to the second leg that matches it synchronously, so that when the first leg has delayed touchdown, the second leg can delay support, that is, continue to be in the support phase, thereby avoiding the situation where both the first leg and the second leg swing.

[0124] Similar to the above steps A1 and A2, similarly, the above step B1 "adding N delayed support control cycles after the last control cycle of the support phase of the gait sequence corresponding to the second leg" includes steps B11 and B12:

[0125] Step B11, when the first control cycle of the second mode gait sequence is in the support phase, N delayed support control cycles are added to the last position of the support subsequence in the second mode gait sequence; the support subsequence is a sequence corresponding to continuous control cycles in the support phase and includes the first control cycle of the second mode gait sequence.

[0126] Step B12, when the first control cycle of the second mode gait sequence is in the swing phase, adding N delayed support control cycles to the initial position of the second mode gait sequence.

[0127] Figure 7 A schematic diagram of generating a second gait sequence is shown. Figure 3The principle of generating the first gait sequence is similar to that shown, except that a delayed support control period in the support phase is added to the gait sequence corresponding to the second leg (which may be referred to as the second mode gait sequence). The resulting second gait sequence is called the second rolling gait sequence, which will not be described in detail here.

[0128] It can be understood that when the first leg touches the ground with a delay and the touchdown is detected, the second leg cooperating with the first leg can enter the swing phase; in order to solve the situation where the second leg also touches the ground with a delay, N delayed support control cycles are added to the gait sequence after the first leg; in other words, the states of the first leg and the second leg are interchanged at this time, and the gait sequences can be generated according to the above-mentioned processing methods.

[0129] In some optional implementations, the above step S404 of “setting a transition control period at the initial position of the gait sequence corresponding to the first leg” may include step C1 and step C2.

[0130] Step C1, when the first control cycle of the gait sequence corresponding to the first leg is in the swing phase, a transition control cycle is set at the initial position of the gait sequence corresponding to the first leg, and each control cycle in the swing phase after the transition control cycle is updated to an early touchdown control cycle in the support phase.

[0131] Step C2, when the first control cycle of the transition control cycle is in the stance phase, the transition control cycle is set at the initial position of the gait sequence corresponding to the first leg, and other control cycles are kept unchanged.

[0132] In this embodiment, when it is detected that the first leg touches the ground, if the first control cycle of the gait sequence corresponding to the first leg (such as the first mode gait sequence) is the stance phase, it means that the first leg just touches the ground or touches the ground with delay, and does not touch the ground in advance. Therefore, as shown in step C2, only the transition control cycle needs to be set at this time, and the remaining control cycles do not need to be changed.

[0133] If the first control cycle of the gait sequence corresponding to the first leg is in the swing phase when the first leg touches the ground, it means that the first leg touches the ground in advance. Therefore, it is necessary to update the front swing subsequence in the gait sequence (the control cycles in which are all swing phases) to the control cycle in the support phase, that is, the early touchdown control cycle.

[0134] Figure 8 FIG. 2 shows a schematic diagram of the process when the ground is touched early. Figure 8 As shown in FIG. 1 , if the first leg touches the ground at the current moment, a transition control period (0.3s to 0.32s) needs to be set for the first mode gait sequence, which is still a swing phase; and each control period of the swing subsequence in the first mode gait sequence is updated to an early touchdown control period, such as Figure 8As shown, there are 4 early touchdown control cycles, corresponding to 0.32s-0.34s, 0.34s-0.36s, 0.36s-0.38s, and 0.38s-0.4s, respectively. Therefore, after the first leg touches the ground early, the first leg is always in the support phase.

[0135] For the second leg that cooperates with the first leg, when the first leg touches the ground, if the first leg touches the ground with delay, the second leg needs to switch to the swing phase afterwards, so it is necessary to add N delayed touchdown control cycles for the second leg based on the method of step S402. If the first leg touches the ground in advance, the second leg can be controlled based on the MPC method first, that is, the second leg is kept in the touchdown state, and after the second leg switches to the swing phase, N delayed touchdown control cycles are added to the second leg based on the method of step S402.

[0136] When the ground is touched in advance, for each early touchdown control cycle, the control amount is used to control the speed and acceleration of the first leg to be zero and the position to remain unchanged, so that the position of the first leg foot end trajectory remains unchanged and always touches the ground. If the ground is touched in advance, the information of the early touchdown of the first leg can also be synchronized to the WBC.

[0137] In this embodiment, the first leg and the second leg are controlled in coordination. While a delayed touchdown control period is added to the first leg, a delayed support control period is added to the second leg to ensure that at least one leg is in the support phase, thereby ensuring the stability of the legged robot.

[0138] In this embodiment, a gait control device for a legged robot is also provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the term "module" may be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0139] This embodiment provides a gait control device for a legged robot, such as Fig. 9 As shown, including:

[0140] A gait module 901, for controlling the legs of the footed robot through a preset gait sequence, wherein the gait sequence includes a swing phase and a stance phase;

[0141] The processing module 902 is configured to, in a current control cycle, when the first leg of the legged robot is currently in a swing phase, if the first leg is not detected to be touching the ground, add N delayed touchdown control cycles after the last control cycle of the swing phase of the gait sequence corresponding to the first leg to generate a first gait sequence; the delayed touchdown control cycle is in the swing phase, and N ≥ 2;

[0142] The publishing module 903 is used to publish the first step sequence so as to control the first leg according to the first step sequence in the subsequent control cycle.

[0143] In some optional implementations, the control amount of the first leg in the delayed touchdown control period is used to:

[0144] The horizontal position of the first leg in the horizontal plane is controlled to remain unchanged, and the horizontal speed is zero; and the vertical speed of the first leg in the vertical direction is controlled to be a preset speed, and the vertical position of the first leg in the vertical direction is determined based on the time integral of the vertical speed.

[0145] In some optional embodiments, the control amount of the first leg includes:

[0146]

[0147] and,

[0148] in, represents the position control amount of the first leg on the horizontal plane X-axis during the delayed touchdown control period, represents the horizontal position of the first leg on the X-axis of the horizontal plane determined in the previous control cycle; represents the position control amount of the first leg on the Y-axis of the horizontal plane during the delayed touchdown control period, represents the horizontal position of the first leg on the Y-axis of the horizontal plane determined in the previous control cycle; represents the speed control amount of the first leg on the horizontal plane X-axis during the delayed touchdown control period, represents the speed control amount of the first leg on the Y-axis of the horizontal plane during the delayed touchdown control period;

[0149] represents a speed control amount of the first leg in the vertical direction during the delayed touchdown control period; Indicates the preset speed; represents the position control amount of the first leg in the vertical direction during the delayed contact control period, represents the vertical position of the first leg in the vertical direction determined in the previous control cycle, t cycle Indicates the duration of the control cycle.

[0150] In some optional embodiments, the legged robot is a quadruped robot;

[0151] In the delayed touchdown control period, the height control amount of the legged robot is used to: determine the body descent speed of the legged robot according to the number of delayed touchdown mechanical legs, and adjust the height of the legged robot according to the body descent speed;

[0152] The pitch angle control amount of the footed robot is used to: when the first leg is the front leg and the hind leg does not touch the ground with delay, control the pitch angle of the footed robot to increase; when the first leg is the hind leg and the front leg does not touch the ground with delay, control the pitch angle of the footed robot to decrease.

[0153] In some optional embodiments,

[0154] in, represents the height control amount of the legged robot, represents the height of the legged robot determined in the previous control cycle, w i represents the weight of the i-th robotic leg, and when the i-th robotic leg does not touch the ground late, w i =0, represents the preset speed, t cycle Indicates the duration of the control cycle; w pitch Indicates the pitch angle weight.

[0155] In some optional embodiments, the processing module 902 is further configured to: in a current control cycle, when the first leg of the footed robot is currently in a swing phase, if the first leg is not detected to be touching the ground, for a second leg cooperating with the first leg, after the last control cycle of the support phase of the gait sequence corresponding to the second leg, add N delayed support control cycles to generate a second gait sequence; the delayed support control cycle is in the support phase;

[0156] The publishing module 903 is further used to: publish the second gait sequence, so as to control the second leg according to the second gait sequence in a subsequent control cycle.

[0157] In some optional implementations, the processing module 902 is further configured to:

[0158] In the current control cycle, if it is detected that the first leg touches the ground, a transition control cycle is set at the initial position of the gait sequence corresponding to the first leg to generate a third gait sequence; the transition control cycle is a control cycle in a swing phase and used for state switching;

[0159] The publishing module 903 is further used to: publish the third gait sequence.

[0160] In some optional implementations, the processing module 902 sets a transition control period at an initial position of the gait sequence corresponding to the first leg, including:

[0161] When the first control cycle of the gait sequence corresponding to the first leg is in the swing phase, a transition control cycle is set at the initial position of the gait sequence corresponding to the first leg, and each control cycle in the swing phase after the transition control cycle is updated to an early ground contact control cycle in the stance phase;

[0162] When the first control cycle of the transition control cycle is in the stance phase, the transition control cycle is set at the initial position of the gait sequence corresponding to the first leg, and other control cycles are kept unchanged.

[0163] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0164] The gait control device of the legged robot in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, including a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0165] The embodiment of the present invention also provides a foot-type robot having a plurality of mechanical legs and the above Fig. 9 The gait control device of the legged robot shown can control the state of each mechanical leg.

[0166] See also Fig.10 , Fig.10 is a schematic diagram of the structure of a legged robot provided by an optional embodiment of the present invention, such as Fig.10 As shown, the legged robot includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses for communication, and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed in the legged robot, including instructions stored in or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used with multiple memories. Similarly, multiple legged robots can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Fig.10 A processor 10 is taken as an example.

[0167] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0168] The memory 20 stores instructions executable by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0169] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and applications required for at least one function; the data storage area may store data created according to the use of the legged robot, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the legged robot via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0170] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0171] The legged robot further comprises a communication interface 30 for the legged robot to communicate with other devices or a communication network.

[0172] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0173] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0174] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations should all be included in the protection scope of the present invention.

Claims

1. A gait control method for a legged robot, characterized in that: The method comprises: Controlling the legs of the footed robot by a preset gait sequence, wherein the gait sequence includes a swing phase and a stance phase; In the current control cycle, when the first leg of the legged robot is currently in the swing phase, if the first leg is not detected to be touching the ground, after the last control cycle of the swing phase of the gait sequence corresponding to the first leg, N delayed touchdown control cycles are added to generate the first gait sequence; the delayed touchdown control cycle is in the swing phase, and N ≥ 2; The first step sequence is issued to control the first leg according to the first step sequence in a subsequent control cycle.

2. The method according to claim 1, characterized in that The control amount of the first leg in the delayed touchdown control period is used to: The horizontal position of the first leg in the horizontal plane is controlled to remain unchanged, and the horizontal speed is zero; and the vertical speed of the first leg in the vertical direction is controlled to be a preset speed, and the vertical position of the first leg in the vertical direction is determined based on the time integral of the vertical speed.

3. The method according to claim 2, characterized in that The control amount of the first leg includes: and, in, represents the position control amount of the first leg on the horizontal plane X-axis during the delayed touchdown control period, represents the horizontal position of the first leg on the X-axis of the horizontal plane determined in the previous control cycle; represents the position control amount of the first leg on the Y-axis of the horizontal plane during the delayed touchdown control period, represents the horizontal position of the first leg on the Y-axis of the horizontal plane determined in the previous control cycle; represents the speed control amount of the first leg on the horizontal plane X-axis during the delayed touchdown control period, represents the speed control amount of the first leg on the Y-axis of the horizontal plane during the delayed touchdown control period; represents a speed control amount of the first leg in the vertical direction during the delayed touchdown control period; Indicates the preset speed; represents the position control amount of the first leg in the vertical direction during the delayed contact control period, represents the vertical position of the first leg in the vertical direction determined in the previous control cycle, t cycle Indicates the duration of the control cycle.

4. The method according to claim 2, characterized in that: The legged robot is a quadruped robot; In the delayed touchdown control period, the height control amount of the legged robot is used to: determine the body descent speed of the legged robot according to the number of delayed touchdown mechanical legs, and adjust the height of the legged robot according to the body descent speed; The pitch angle control amount of the footed robot is used to: when the first leg is the front leg and the hind leg does not touch the ground with delay, control the pitch angle of the footed robot to increase; when the first leg is the hind leg and the front leg does not touch the ground with delay, control the pitch angle of the footed robot to decrease.

5. The method according to claim 4, characterized in that in, represents the height control amount of the legged robot, represents the height of the legged robot determined in the previous control cycle, w i represents the weight of the i-th robotic leg, and when the i-th robotic leg does not touch the ground late, w i =0, represents the preset speed, t cycle Indicates the duration of the control cycle; w pitch Indicates the pitch angle weight.

6. The method according to claim 1, characterized in that Also includes: In the current control cycle, when the first leg of the footed robot is currently in the swing phase, if the first leg is not detected to be touching the ground, for the second leg coordinated with the first leg, after the last control cycle of the support phase of the gait sequence corresponding to the second leg, N delayed support control cycles are added to generate a second gait sequence; the delayed support control cycle is in the support phase; The second gait sequence is issued to control the second leg according to the second gait sequence in a subsequent control cycle.

7. The method according to claim 1, characterized in that Also includes: In the current control cycle, if it is detected that the first leg touches the ground, a transition control cycle is set at the initial position of the gait sequence corresponding to the first leg to generate a third gait sequence; the transition control cycle is a control cycle in a swing phase and used for state switching; The third gait sequence is released.

8. The method according to claim 7, characterized in that The step of setting a transition control period at an initial position of a gait sequence corresponding to the first leg comprises: When the first control cycle of the gait sequence corresponding to the first leg is in the swing phase, a transition control cycle is set at the initial position of the gait sequence corresponding to the first leg, and each control cycle in the swing phase after the transition control cycle is updated to an early ground contact control cycle in the stance phase; When the first control cycle of the transition control cycle is in the stance phase, the transition control cycle is set at the initial position of the gait sequence corresponding to the first leg, and other control cycles are kept unchanged.

9. A gait control device for a legged robot, characterized in that: The device comprises: A gait module, for controlling the legs of the footed robot through a preset gait sequence, wherein the gait sequence includes a swing phase and a stance phase; A processing module, configured to, in a current control cycle, when the first leg of the legged robot is currently in a swing phase, if the first leg is not detected to have touched the ground, add N delayed touchdown control cycles after the last control cycle of the swing phase of a gait sequence corresponding to the first leg to generate a first gait sequence; the delayed touchdown control cycle is in the swing phase, and N ≥ 2; A publishing module is used to publish the first step sequence so as to control the first leg according to the first step sequence in a subsequent control cycle.

10. A legged robot, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the gait control method of the legged robot according to any one of claims 1 to 8 by executing the computer instructions.

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