A foot-type robot

Abstract

The application discloses a kind of foot type robots, for improving the connection between actions, alleviate the segmented feeling in the process of getting up.The foot type robot provided by the application comprises a torso, an upper torso and a hip part connected with each other in rotation, two upper limbs and corresponding upper limb ends, the two upper limbs are connected with the upper torso respectively, two lower limbs and corresponding lower limb ends, the two lower limbs are connected with the hip part respectively, wherein the first upper limb in the two upper limbs and the first lower limb in the two lower limbs are located on the same side of the sagittal plane of the upper torso, the second lower limb in the two lower limbs and the first lower limb are located on different sides of the sagittal plane of the upper torso;At least one storage medium stores instructions, the instructions are executed by at least one processor to make the foot type robot: in response to receiving a getting-up trigger instruction, control the foot type robot to execute a getting-up action sequence, the getting-up action sequence includes a same-side upper and lower limb support stage, a double lower limb low support stage and a double foot support stage in turn.

Description

Technical Field

[0001] This application relates to the field of robot control technology, and in particular to a legged robot. Background Technology

[0002] In some existing standing-up solutions, the robot needs to gradually stand up by following multiple pre-set intermediate postures, switching between different support states by adjusting the position of the torso and limbs. In this process, the robot often needs to adjust to the corresponding intermediate posture before continuing to move the limbs or change the support position. The connection between torso movement, limb adjustment and support transition is not sufficient, and pauses or additional posture adjustments are likely to occur between different actions. This makes the standing-up process exhibit obvious segmented characteristics, and the movements are relatively mechanical and stiff, with low overall coherence and smoothness. Summary of the Invention

[0003] This application provides a legged robot for improving the connection between movements and reducing the segmented feeling during the standing process.

[0004] This application provides a legged robot, comprising: The torso, including the upper torso and hips that are rotated and connected to each other; Two upper limbs and corresponding upper limb ends, the two upper limbs being connected to the upper torso; Two lower limbs and corresponding lower limb ends, the two lower limbs being connected to the hip; wherein, the first upper limb of the two upper limbs and the first lower limb of the two lower limbs are located on the same side of the sagittal plane of the upper trunk, and the second lower limb of the two lower limbs and the first lower limb are located on different sides of the sagittal plane of the upper trunk; At least one processor; and, At least one storage medium storing instructions that, when executed by the at least one processor, cause the legged robot to: In response to receiving a stand-up trigger command, the legged robot is controlled to execute a stand-up action sequence, which includes, in sequence, a support phase of the same side upper and lower limbs, a low support phase of both lower limbs, and a support phase of both feet. During the ipsilateral upper and lower limb support phase, at least one part of the first upper limb and at least one part of the first lower limb are controlled to make contact with the contact surface support. Control the first upper limb to release the support contact with the contact surface, so that the legged robot enters the dual lower limb low support stage. In the dual lower limb low support stage, the knee joint of the first lower limb and the lower limb end of the second lower limb respectively make support contact with the contact surface. Control the knee joint of the first lower limb to release its support contact with the contact surface, and control the lower limb end of the first lower limb to make support contact with the contact surface, so that the legged robot enters the bipedal support phase. In the bipedal support phase, the lower limb ends of the two lower limbs respectively make support contact with the contact surface.

[0005] As can be seen from the above technical solutions, this application has the following advantages: The robot achieves a coordinated transition between ipsilateral upper and lower limb support, bilateral lower limb low-position support, and bilateral foot support, allowing changes in limb posture adjustment and body support relationship. In the initial standing phase, the ipsilateral first upper and lower limbs work together to provide support, offering a foundation for trunk and lower limb position adjustments. Bilateral lower limb low-position support is formed by the knee joint of the first lower limb and the distal end of the second lower limb, enabling the robot to bear weight with both lower limbs before the first lower limb completes its transition to foot support, while the first upper limb relinquishes its support. Subsequently, the transition to bilateral foot support is completed by the knee joint of the first lower limb relinquishing its support and the distal end of the lower limb participating in support.

[0006] In the above process, the first lower limb initially participates in load-bearing through the knee, and then transitions to end-body support. This allows the adjustment of the lower limb position to seamlessly connect with the shift in support tasks, and the body's support gradually transfers to the ends of both lower limbs as the limbs move. This provides conditions for the continuous execution of trunk adjustment, upper limb withdrawal, and lower limb support transition, improves the connection between movements, reduces the segmented feeling during the standing process, and makes the standing movement more natural and fluid. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 A schematic diagram of the overall structure of a humanoid robot provided as an example of a legged robot for this application; Figure 2 A flowchart illustrating an embodiment of the legged robot performing a standing motion sequence provided in this application; Figure 3 A schematic diagram of a posture of the legged robot provided in this application during the ipsilateral upper and lower limb support phase; Figure 4 A schematic diagram of the posture of the legged robot provided in this application when the first upper limb releases its support contact with the contact surface; Figure 5A schematic diagram of a posture of the legged robot provided in this application during the low-position support phase of both lower limbs; Figure 6 A schematic diagram of another posture of the legged robot provided in this application during the low-position support phase of both lower limbs; Figure 7 This is a schematic diagram of the posture of the legged robot provided in this application when the knee joint of the first lower limb is disengaged from the contact surface. Detailed Implementation

[0009] This application provides a legged robot for improving the connection between movements and reducing the segmented feeling during the standing process.

[0010] The legged robot provided in this application includes a torso, a head, two upper limbs, two lower limbs, at least one processor, and at least one storage medium. In some embodiments, the legged robot can be a humanoid robot, which is a specific implementation of a legged robot. For ease of description, the following mainly uses a humanoid robot as an example, and is referred to as a robot. Please refer to [link to relevant documentation]. Figure 1 The torso 3 includes an upper torso 31 and a hip 32, which are rotatably connected to each other via a power module 33. The head 4 is connected to the upper torso 31, the two upper limbs 1 are connected to the upper torso 31 respectively, and the two lower limbs 2 are connected to the hip 32 respectively. For ease of description, the two upper limbs can be referred to as the first upper limb and the second upper limb, and the two lower limbs can be referred to as the first lower limb and the second lower limb respectively. It should be noted that the terms first upper limb, second upper limb, first lower limb, and second lower limb are only used to distinguish different limb structures and do not constitute a limitation on specific left and right positions.

[0011] Each upper limb includes an end effector for establishing supporting contact with the contact surface. Each upper limb may also include an upper arm and a forearm. The upper arm is connected to the upper torso, and the forearm is connected to the end effector. The upper arm and forearm are connected via an elbow joint. Each lower limb includes an end effector for establishing supporting contact with the contact surface. Each lower limb may also include a thigh and a lower leg. The thigh is connected to the hip, and the lower leg is connected to the end effector. The knee joint is located between the thigh and the lower leg and is a joint assembly between the thigh and the lower leg, used to realize the flexion and extension swing of the lower leg relative to the thigh. The knee joint assembly includes a portion of the thigh and the lower leg near the knee joint. It should be noted that the contact surface can be the ground, platform surface, sports field surface, cushioning surface, or other bearing surface that can provide support for the legged robot; the end effector of the upper limb can be a palm, a robotic hand, or other end structure that can establish supporting contact with the contact surface; the end effector of the lower limb can be a foot, a foot actuator, or other end structure that can establish supporting contact with the contact surface. This application does not limit the scope of the application.

[0012] It should be noted that, in the embodiments of this application, "contact" refers to the state in which the limbs, torso, or other body parts of the legged robot are in physical contact with the contact surface; "supporting contact" refers to the state in which the above-mentioned contact provides support to the legged robot, enabling the corresponding part to bear part of the load from the body. Specifically, when a part of the legged robot only makes slight contact, rubbing, or non-load-bearing contact with the contact surface, that part can be understood as having ordinary contact with the contact surface; when there is a contact between that part and the contact surface that can bear the weight of the body or participate in posture stability, that part can be understood as establishing supporting contact with the contact surface. Whether supporting contact is established can be determined by force sensors, tactile sensors, joint torque, motor current, contact pressure distribution, or posture changes.

[0013] At least one of the aforementioned storage media stores instructions that, when executed by at least one processor, control the coordinated operation of the various drive components of the legged robot to enable the legged robot to execute a sequence of standing actions in response to receiving a standing trigger instruction. The phrase "receiving a standing trigger instruction" in this application can refer to the legged robot receiving an externally input standing trigger instruction, or it can refer to the legged robot receiving a standing trigger instruction automatically generated by the legged robot based on its own state or motion planning results. The standing action sequence is divided into three stages according to the changing support relationship between the robot and the contact surface: a stage of ipsilateral upper and lower limb support, a stage of bilateral lower limb low-position support, and a stage of bilateral foot support. During the standing process, the robot gradually changes the support points bearing the body load: first, it uses the first upper limb and first lower limb located on the same side of the torso to establish a support foundation for the initial stage of standing; then, the first upper limb gradually withdraws from support, and the body load is borne by the knee joint of the first lower limb and the lower limb ends of the second lower limb, forming bilateral lower limb low-position support; based on this, the first lower limb is then changed from knee joint support to lower limb end support, so that the lower limb ends of both lower limbs jointly bear the body load. Thus, the robot is able to disengage its first upper limb from the body support process before establishing bipedal support, and gradually complete the standing process by switching support between its two lower limbs. (See also...) Figure 2 , Figure 2 A schematic flowchart of an embodiment of the sequence of actions to stand up provided in this application is shown. The embodiment includes: 201. During the ipsilateral upper and lower limb support phase, at least one part of the first upper limb and at least one part of the first lower limb are controlled to make contact with the contact surface for support. In this embodiment, when the legged robot is in a reference posture with its upper torso and hips facing the same direction, the sagittal plane, which passes through the middle of the upper torso and extends along the vertical and horizontal directions of the upper torso itself, is used as the reference plane to divide the left and right sides of the upper torso. Based on the connection position of the limbs to the torso in this reference posture, an upper limb and a lower limb connected to the same side of the sagittal plane of the upper torso are designated as the first upper limb and the first lower limb, respectively, and the lower limb connected to the other side of the sagittal plane of the upper torso is designated as the second lower limb. This lateral relationship is determined by the structural connection relationship of the limbs and remains unchanged during rotation of the upper torso relative to the hips or limb movement. When a part of the limb structure or the limb end moves to the other side of the reference plane, the originally determined limb name is still used.

[0014] In response to a stand-up trigger command, the processor controls the legged robot to execute a stand-up sequence. Once the stand-up sequence begins, the processor coordinates the movement of the torso, first upper limb, and first lower limb, enabling the first upper limb and first lower limb, located on the same side of the torso, to establish supporting contact with the contact surface through one or more of their own parts. This allows the robot's load to be simultaneously transferred to the contact surface via the first upper limb and first lower limb, thus entering the ipsilateral upper and lower limb support phase. In this ipsilateral upper and lower limb support phase, the first upper limb provides auxiliary support, while the first lower limb participates in the body's load-bearing capacity. Both provide a supporting basis for adjusting the torso posture and lower limb position. Under this support relationship, the robot can further adjust the torso posture and the position of the two lower limbs, providing conditions for the two lower limbs to further participate in the body's load-bearing capacity.

[0015] It should be noted that the specific locations where the first upper limb and the first lower limb establish supporting contact are not limited, as long as at least one part of the first upper limb and at least one part of the first lower limb can participate in the support of the robot body through the force between them and the contact surface. They can establish supporting contact sequentially or during the same continuous movement. The contact state of other parts of the robot with the contact surface can change with the current posture. For example, the hip can form supporting contact with the contact surface and bear part of the robot's load, or it can simply maintain contact with the contact surface without bearing much of the supporting function, or it can separate from the contact surface. Therefore, this stage is mainly determined by whether the first upper limb and the first lower limb participate in the support of the robot body.

[0016] 202. Control the first upper limb to release the support contact with the contact surface, so that the legged robot enters the low support phase of the two lower limbs. In the low support phase of the two lower limbs, the knee joint of the first lower limb and the lower limb end of the second lower limb respectively make support contact with the contact surface. During the transition from the ipsilateral upper and lower limb support phase to the dual lower limb low-position support phase, the processor coordinates and controls the first upper limb and both lower limbs to release the first upper limb from the contact surface and to make the knee joint of the first lower limb and the lower limb ends of the second lower limbs into contact with the contact surface, respectively. The moment when the first upper limb releases its support contact can be earlier than, later than, or simultaneously with the moment when the knee joint of the first lower limb and the lower limb ends of the second lower limbs establish support contact; the specific timing is determined based on the robot's current posture and support state.

[0017] In one implementation, the first upper limb first releases its supporting contact with the contact surface, and the two lower limbs coordinate to adjust their posture, so that the knee joint of the first lower limb and the distal end of the second lower limb subsequently form a relationship of jointly participating in the support of the body. For example, when the knee joint of the first lower limb has already participated in the support, the first upper limb first withdraws from the support, and the distal end of the second lower limb then establishes supporting contact with the contact surface. In another implementation, the knee joint of the first lower limb and the distal end of the second lower limb first establish supporting contact with the contact surface respectively, and the first upper limb continues to participate in the support during this process, so that the first upper limb and the two lower limbs jointly bear the load of the body; subsequently, the first upper limb releases its supporting contact with the contact surface, and the two lower limbs continue to participate in the support of the body. In yet another implementation, the release of the first upper limb from the supporting contact and the formation of the joint supporting relationship between the two lower limbs are completed simultaneously. For example, when the knee joint of the first lower limb has already participated in the support, the distal end of the second lower limb establishes supporting contact, and at the same time, the first upper limb releases its supporting contact with the contact surface.

[0018] All three implementation methods involve, upon completing this transition, causing the first upper limb to retract from the support, and the knee joint of the first lower limb and the distal end of the second lower limb to make contact with the support surface, thereby completing the transition to the low-lying support phase of both lower limbs. The release of the first upper limb from the support contact indicates that all parts of it have exited the support state; the actual moment of separation from the contact surface depends on the specific movement process of the first upper limb.

[0019] During the low-lying support phase, the first lower limb forms a low-lying support with its knee joint, while the second lower limb forms another support with its lower extremities. This allows the robot to share the load between its two lower limbs even before entering the bipedal support phase. Consequently, the first upper limb can withdraw from support during the mid-stage of the standing process, and subsequent adjustments to the posture of the first lower limb and changes in support position can be primarily accomplished through the coordinated support between the two lower limbs, thus reducing the need for the first upper limb to continuously bear the load.

[0020] During this phase, the distal end of the first lower limb can participate in support, maintain non-supported contact with the contact surface, or leave the contact surface; its specific state does not affect the determination of the support relationship during this phase. Similarly, the specific direction and trajectory of movement of the second lower limb are not limited, as long as the distal end of the second lower limb can establish support with the contact surface and share the body load with the knee joint of the first lower limb.

[0021] 203. Control the knee joint of the first lower limb to release the support contact with the contact surface, and control the lower limb end of the first lower limb to make support contact with the contact surface, so that the legged robot enters the bipedal support stage. In the bipedal support stage, the lower limb ends of the two lower limbs respectively make support contact with the contact surface.

[0022] During the transition from the low-lying support phase to the bipedal support phase, the processor controls the first lower limb to adjust its posture and end-effector position, causing the knee joint of the first lower limb to release support and allowing the end-effector of the first lower limb to participate in the load-bearing process. If the end-effector of the first lower limb was already participating in support, it can continue to bear the load by coordinating with the knee joint to release support; if the end-effector of the first lower limb was previously in unsupported contact or off-ground, it adjusts its posture to make contact with the support surface. Upon entering the bipedal support phase, the knee joint of the first lower limb has released support, and the ends of both lower limbs are in contact with the support surface, jointly bearing the load of the body.

[0023] Through the coordinated transitions between these phases, the robot sequentially decouples its first upper limb and then its first lower limb's knee joint during the entire standing process, gradually transferring the load to the extremities of both lower limbs. This eliminates the need for the first upper limb to bear the load during the latter part of the standing process, allowing the two lower limbs to continue adjusting the robot's posture based on the established bipedal support. During the bipedal support phase, the robot can continue to control the extension of its two lower limbs, gradually increasing the angle between their knee joints. This extension movement of the lower limbs lifts the hips and upper torso away from the contact surface until the robot returns to a standing position.

[0024] In this embodiment, the transitions between ipsilateral upper and lower limb support, bilateral lower limb low-position support, and bilateral foot support allow for coordinated adjustments in limb posture and changes in the body's support relationship. In the initial standing phase, the ipsilateral first upper limb and first lower limb jointly provide support, offering a foundation for adjusting the position of the torso and lower limbs. Bilateral lower limb low-position support is formed by the knee joint of the first lower limb and the distal end of the second lower limb, enabling the robot to bear weight with both lower limbs before the first lower limb has completed its transition to foot support, while the first upper limb withdraws from support. Subsequently, the transition to bilateral foot support is completed by the knee joint of the first lower limb withdrawing from support and the distal end of the lower limb participating in support.

[0025] In the above process, the first lower limb initially participates in load-bearing through the knee, and then transitions to end-body support. This allows the adjustment of the lower limb position to seamlessly connect with the shift in support tasks, and the body's support gradually transfers to the ends of both lower limbs as the limbs move. This provides conditions for the continuous execution of trunk adjustment, upper limb withdrawal, and lower limb support transition, improves the connection between movements, reduces the segmented feeling during the standing process, and makes the standing movement more natural and fluid.

[0026] In some embodiments, during the ipsilateral upper and lower limb support phase: the angle between the sagittal axis of the upper trunk and the contact surface is 0° to 60°, and the angle is an acute angle between the sagittal axis and the contact surface; the elbow joint, wrist joint, or distal end of the first upper limb is in support contact with the contact surface, and the knee joint of the first lower limb is in support contact with the contact surface, and the knee joint angle of the first lower limb is 30° to 120°; a plane that intersects the thigh, knee joint, and calf of the first lower limb simultaneously is used as the first reference plane, and the angle between the first reference plane and the contact surface is 0° to 75°.

[0027] Please see Figure 3 , Figure 3 This is a schematic diagram of a legged robot's posture during the ipsilateral upper and lower limb support phase. In this embodiment, the angle between the sagittal axis of the upper torso and the contact surface is 0° to 60°. The sagittal axis of the upper torso can be understood as a reference axis extending along the anteroposterior direction of the upper torso and used to indicate the orientation of the upper torso. Figure 3 In this diagram, A represents the contact surface, B represents the sagittal axis, and α represents the angle between the sagittal axis and the contact surface. For example, this angle α can be 0°, 10°, 20°, 30°, 45°, or 60°, where 0° indicates that the sagittal axis is parallel to the contact surface. By limiting this angle within the above range, the degree of inclination of the upper torso in the anterior-posterior direction relative to the contact surface is constrained. Figure 3 As shown, in a configuration where the upper and lower limbs on the same side jointly participate in support, the upper torso maintains an inclined posture and coordinates with limb movements, providing a postural basis for subsequently transferring body support to the two lower limbs. When this angle changes, the orientation of the upper torso changes accordingly, and the lever arm relationship between the body's center of gravity and the load-bearing position of the first upper limb is also affected by the torso position and limb configuration. Therefore, the angle is used to define the orientation range of the upper torso, and the actual height of the upper torso off the ground is determined in conjunction with the limb support relationship shown in the figure.

[0028] During the ipsilateral upper and lower limb support phase, the first upper limb can form supporting contact with the contact surface through the elbow joint, wrist joint, or the distal end of the upper limb. Different support points can correspond to different flexion and extension states of the first upper limb and cooperate with different trunk positions to form support. For example, the robot can use the elbow joint or wrist joint for support, or it can adjust the posture of the first upper limb to use the distal end of the upper limb for support. The robot can select the contact point suitable for forming the ipsilateral upper and lower limb support state based on the current posture, trunk height, and limb configuration. Figure 3 This illustrates one limb configuration when the first upper limb and the first lower limb cooperate for support. All of the above-mentioned different upper limb contact methods can be used to form the ipsilateral support relationship required in this stage.

[0029] The knee joint of the first lower limb makes contact with the contact surface, and the knee joint angle of the first lower limb is between 30° and 120°. For example, the knee joint angle of the first lower limb can be 30°, 45°, 60°, 75°, 90°, 105°, or 120°. When the knee joint angle of the first lower limb is small, the first lower limb has a greater degree of flexion, which is beneficial for lowering the hip position and forming low-position support through the knee joint; however, when the knee joint angle is less than 30°, the degree of folding between the thigh and lower leg further increases, making it easier to approach the joint limit, and the adjustable space of the first lower limb is reduced, which is not conducive to subsequently releasing the knee joint support and adjusting the position of the end of the first lower limb. When the knee joint angle of the first lower limb is greater than 120°, the extension of the first lower limb is higher, and the constraint on the hip and torso posture when the knee joint establishes low-position support with the contact surface increases, which is also not conducive to the robot maintaining a low body posture. Therefore, controlling the knee joint angle of the first lower limb between 30° and 120° allows the first lower limb to have sufficient flexion to form knee support while reserving space for subsequent transition from knee support to lower limb end support.

[0030] Furthermore, the plane that intersects simultaneously with the thigh, knee joint and calf of the first lower limb is used as the first reference plane, and the angle between the first reference plane and the contact surface is 0° to 75°. Figure 3 In the diagram, A represents the contact surface, C represents the first reference plane, and β represents the angle between the first reference plane C and the contact surface A. For example, the angle β can be 0°, 15°, 30°, 45°, 60°, or 75°. The first reference plane is used to describe the configuration of the first lower limb relative to the contact surface from a spatial perspective. The smaller the angle between this plane and the contact surface, the closer the selected reference plane is to being parallel to the contact surface; the larger the angle, the greater the inclination of the selected reference plane relative to the contact surface. Combined with the knee joint support and flexion state of the first lower limb, this angle condition further defines the spatial posture of the first lower limb in the illustrated low-position support configuration, providing a posture basis for subsequent adjustments to the support relationship between the two lower limbs.

[0031] It should be noted that since the thigh, knee joint, and lower leg of the first lower limb all have three-dimensional geometric dimensions, multiple planes can simultaneously intersect with the thigh, knee joint, and lower leg. Therefore, the first reference plane is not limited to a unique plane. Multiple planes that can simultaneously intersect with the thigh, knee joint, and lower leg of the first lower limb can be considered as candidate first reference planes. When any of these first reference planes has an angle between itself and the contact surface within the range of 0° to 75°, the first lower limb can be considered to satisfy the posture constraints of the aforementioned first reference plane. Thus, this parameter is used to define the overall spatial posture range of the first lower limb, without limiting it to a single geometric plane.

[0032] Through the configuration of this embodiment, the sagittal axis angle of the upper trunk, the knee joint angle of the first lower limb, and the angle of the first reference plane define the ipsilateral upper and lower limb support phase from three aspects: upper trunk posture, local joint configuration of the first lower limb, and overall spatial posture of the first lower limb. The cooperation of these three aspects enables the robot to maintain a low body posture when the first upper limb and the first lower limb jointly participate in support, and to maintain a flexion configuration of the first lower limb suitable for knee support and subsequent posture adjustment, thereby providing a postureal basis for the first upper limb to exit support and for the two lower limbs to further form a low-position support relationship.

[0033] In this embodiment, the knee joint of the first lower limb is used for support during the ipsilateral upper and lower limb support phase, so that the anterior support configuration of the first lower limb is connected with the knee support used in the subsequent low-position support phase of both lower limbs. The first upper limb bears the body load through the elbow joint, wrist joint, or upper limb end. The two lower limbs can continue to adjust their positions based on this configuration, providing conditions for the first upper limb to withdraw from support and for the end of the second lower limb to participate in support.

[0034] In some embodiments, the legged robot further includes a head connected to the upper torso, wherein when the first upper limb releases its support contact with the contact surface: the angle between the sagittal axis of the upper torso and the contact surface is 0° to 75°, and the angle is an acute angle between the sagittal axis and the contact surface; along the direction perpendicular to the contact surface, the minimum distance between the head and the contact surface is a first distance, and the minimum distance between the hip and the contact surface is a second distance, and the ratio of the first distance to the second distance is greater than or equal to 1; the knee joint angle of the first lower limb is 30° to 120°.

[0035] Please see Figure 4 , Figure 4This is a schematic diagram of a legged robot's posture when the first upper limb releases its support contact with the contact surface. In this embodiment, during the transition from a stage of support by the same-side upper and lower limbs to a stage of low-position support by both lower limbs, the action of the first upper limb retracting its support coordinates with the action of the two lower limbs bearing the load of the robot. Specifically, the support load borne by the first upper limb can decrease as the load-bearing state of the lower limbs changes, and eventually the support contact between the first upper limb and the contact surface is released. Here, the release of support contact by the first upper limb means that all parts of the first upper limb have withdrawn from the support state of bearing the load of the robot or assisting in maintaining the robot's posture. When the first upper limb has multiple parts involved in support, the moment when the last part that bears the support releases its support is taken as the moment when the first upper limb releases its support contact with the contact surface. At this moment, the first upper limb may still have ordinary contact with the contact surface.

[0036] When the first upper limb releases its supporting contact with the contact surface, the angle between the sagittal axis of the upper trunk and the contact surface can be from 0° to 75°. For example... Figure 4 As shown, Figure 4 In the diagram, A represents the contact surface, B represents the sagittal axis, and α represents the angle between the sagittal axis and the contact surface. For example, the angle α can be 0°, 15°, 30°, 45°, 60°, or 75°. The smaller the angle α, the closer the sagittal axis is to being parallel to the contact surface; the larger the angle, the greater the inclination of the sagittal axis relative to the contact surface. At this moment, the angle α is used to define the posture of the upper trunk relative to the contact surface when the first upper limb withdraws from support, ensuring that the upper trunk remains within the range of transition from a low position to an elevated position when the first upper limb withdraws from support, avoiding the requirement for the first upper limb to continuously bear support until the upper trunk is nearly upright. Therefore, before the upper trunk is fully elevated, subsequent body support can be further transferred to the two lower limbs.

[0037] Along a direction perpendicular to the contact surface, the minimum distance between the head and the contact surface is the first distance, and the minimum distance between the groin and the contact surface is the second distance. For example... Figure 4 As shown, d1 represents the first distance, and d2 represents the second distance. Both can be determined according to the minimum distance between the outer surfaces of the head and hips facing the contact surface and the contact surface, respectively. In this embodiment, the second distance is greater than 0, and the ratio of the first distance to the second distance is greater than or equal to 1, i.e., d1 / d2 ≥ 1. For example, this ratio can be 1, 1.2, 1.5, 1.8, 2, or 2.5. When the ratio is equal to 1, the minimum ground clearance of the head and hips is equal; when the ratio is greater than 1, the minimum ground clearance of the head is greater than the minimum ground clearance of the hips. This ratio is used to define the relative ground clearance state of the head and hips when the first upper limb exits support, and together with the sagittal axis angle of the upper torso, it describes the body posture and coordinates with the support adjustment of the two lower limbs, connecting the low-position support stage of both lower limbs.

[0038] When the first upper limb releases its support from the contact surface, the knee joint angle of the first lower limb can be between 30° and 120°. For example, the knee joint angle of the first lower limb can be 30°, 45°, 60°, 75°, 90°, 105°, or 120°. Within this angle range, the first lower limb can maintain a certain degree of flexion, allowing the knee joint to remain in a position suitable for forming low-level support, while reserving space for subsequent release of knee joint support and adjustment of the lower limb's distal end position. Thus, when the first upper limb withdraws from support, the first lower limb can still bear the body load through its flexion configuration and connect with the subsequent release of knee joint support and adjustment of the lower limb's distal end position.

[0039] It should be noted that the specific support method of the first upper limb before exiting support is determined based on the limb configuration when the robot enters the ipsilateral upper and lower limb support phase. The above posture parameters all correspond to the moment when the first upper limb exits support as a whole.

[0040] In one embodiment, the first upper limb forms a supporting contact with the contact surface via its elbow joint, and the support is directly released by the elbow joint. During this process, the first upper limb bears part of the body load through its elbow joint and adjusts the supporting state in coordination with the movement of the two lower limbs. When the elbow joint releases the support and no other part of the first upper limb bears any supporting role, the first upper limb as a whole releases its supporting contact with the contact surface. At this time, the robot satisfies the posture conditions of the sagittal axis angle of the upper torso, the ratio of the first distance to the second distance, and the knee joint angle of the first lower limb.

[0041] In another implementation, the first upper limb first forms supporting contact with the contact surface through the elbow joint, and adjusts its posture during the rising process, so that the supporting part shifts from the elbow joint to the upper limb end. Specifically, the elbow joint releasing the support and the upper limb end participating in the support are coordinated, and the first upper limb continues to undertake the body support task through the upper limb end. In this case, when the elbow joint withdraws from the support, the first upper limb still participates in the support through the upper limb end; the moment when the upper limb end releases the support and all other parts of the first upper limb have withdrawn from the support is taken as the moment when the first upper limb as a whole releases the support. Figure 4 α, d1, and d2, as well as the knee joint angle of the first lower limb, are all determined based on the robot's posture at that moment.

[0042] In another embodiment, the first upper limb directly forms supporting contact with the contact surface through its distal end. During the rising process, the distal end of the upper limb participates in the body support through the force between itself and the contact surface, and adjusts the load-bearing state in coordination with the movement of the two lower limbs. The processor controls the distal end of the upper limb to release the support; when the distal end retracts from the body support and no other part of the first upper limb participates in the support, the first upper limb as a whole retracts from the support. At this time, the angle between the sagittal axis of the upper trunk and the contact surface, the ratio of the first distance to the second distance, and the knee joint angle of the first lower limb are determined based on the moment the distal end retracts from the support.

[0043] In this embodiment, the sagittal angle of the upper trunk defines the orientation of the upper trunk when the first upper limb withdraws from support; the ratio of the first distance to the second distance defines the relative ground clearance of the head and hips; and the knee joint angle of the first lower limb defines the flexion configuration of the lower limb. These conditions respectively define the orientation of the upper trunk, the relative ground clearance of the head and hips, and the degree of flexion of the first lower limb, ensuring that the posture of the first upper limb when withdrawing from support is constrained by both the trunk and lower limbs. Specifically, the first lower limb maintains a flexion configuration when the upper limb withdraws, aligning with the subsequent requirement of using the first knee to participate in low-lying support of both lower limbs; the distance relationship between the head and hips further clarifies the relative position of the body at the moment of support transition.

[0044] In some embodiments, during the low-lying support phase of both lower limbs: the minimum distance between the knee joints of the first lower limb and the knee joints of the second lower limb is the third distance, the minimum distance between the lower limb ends of the first lower limb and the lower limb ends of the second lower limb is the fourth distance, and the ratio of the third distance to the fourth distance is greater than or equal to 1.5.

[0045] Please see Figure 5 , Figure 5 This is a schematic diagram of a legged robot in a low-lying, dual-leg support phase. In this embodiment, in conjunction with the aforementioned action of the first upper limb withdrawing from support, the processor coordinates the movement of both lower limbs, causing the knee joint of the first lower limb and the distal end of the second lower limb to respectively contact the support surface, forming a low-lying, dual-leg support state. Figure 5 As shown, d3 represents the third distance between the knee joint of the first lower limb and the knee joint of the second lower limb, and d4 represents the fourth distance between the lower limb ends of the first lower limb and the lower limb ends of the second lower limb. Both satisfy d3 / d4≥1.5.

[0046] The third distance represents the relative separation of the knees of the two lower limbs in the current low-support configuration, while the fourth distance represents the relative separation of the extremities of the two lower limbs. The third distance is determined by the shortest spatial distance between the outer surfaces of the knee joints, and the fourth distance is determined by the shortest spatial distance between the outer surfaces of the extremities of the two lower limbs; both correspond to the robot's posture at the same moment. In this embodiment, the fourth distance is greater than 0, and the ratio of the third distance to the fourth distance can be 1.5, 1.8, 2, 2.5, or 3. For example, when the third distance is 300mm and the fourth distance is 200mm, the ratio is 1.5; when the third distance is 360mm and the fourth distance is 180mm, the ratio is 2. The specific values ​​mentioned above are only used to illustrate the relative relationship between the two distances; the actual distances are adjusted according to the overall size of the robot, the length of the lower limbs, and the joint structure.

[0047] When the ratio of the third distance to the fourth distance is greater than or equal to 1.5, the minimum distance between the two knees is greater than the minimum distance between the two lower limbs. For example... Figure 5 As shown, the two lower limbs form a spatial configuration with the knees relatively spread out and the ends of the lower limbs relatively close together. Here, "relatively spread out" and "relatively close together" refer to the size relationship between the distance between the knees and the distance between the feet, and their specific spatial direction depends on the position and orientation of the two lower limbs. This proportional condition, combined with the support relationship between the first knee and the ends of the second lower limbs and the contact surface, collectively describes a specific configuration in the low-position support phase of the two lower limbs.

[0048] In this configuration, the first lower limb provides low-level support via its knee joint, while the second lower limb provides support via its distal end, with both limbs sharing the load. Simultaneously, the distal ends of the two limbs maintain a smaller distance than the knees. Thus, as the robot bears load through the knees and the distal end of the opposite lower limb, a relatively close position is established between the distal ends of the two limbs, providing a configurational basis for the subsequent adjustment of the first lower limb to its distal end support posture. The robot further controls the knee joint of the first lower limb to release support and brings the distal end of the first lower limb into contact with the support surface, thereby transitioning to the dual-foot support phase.

[0049] It should be noted that the third and fourth distances are used to define the relative spatial relationship between the two lower limbs during the low-position support phase, and the specific arrangement of the two lower limbs can vary. For example, the two lower limbs can be located on either side of the torso, and their ends can be brought closer together through posture adjustments; alternatively, one lower limb can extend towards the side where the other lower limb is located, forming a cross arrangement; or they can be arranged in different directions of tilting depending on the current body posture. For the above arrangements, when the knee joint of the first lower limb and the lower limb ends of the second lower limb participate in support respectively, and the third and fourth distances satisfy the above proportional relationship, they all meet the support configuration requirements of this embodiment.

[0050] Through the above setup, after the first upper limb withdraws from support, the two lower limbs jointly participate in bearing the load through different contact positions at the knees and feet, maintaining a configuration with a relatively large distance between the knees and a relatively small distance between the feet. This provides a corresponding positional basis for the transition between the low-position support of both lower limbs and the subsequent support position of the first lower limb. This embodiment builds upon the aforementioned posture conditions when the first upper limb withdraws from support, further clarifying the relative positions of the two lower limbs during the low-position support stage. The aforementioned conditions define the body orientation, the relative ground clearance of the head and hips, and the degree of flexion of the first lower limb when the upper limb withdraws; this embodiment defines the specific arrangement of the two lower limbs when undertaking the support task through the ratio of the knee distance to the distal end distance. The combination of these two aspects clarifies the posture conditions for the connection between the withdrawal of the upper limb from support and the low-position support of both lower limbs.

[0051] In some embodiments, during the low-lying support phase of both lower limbs: a plane that intersects simultaneously with the thigh, knee joint, and calf of the first lower limb is used as a first reference plane, and a plane that intersects simultaneously with the thigh, knee joint, and calf of the second lower limb is used as a second reference plane; a first included angle between the first reference plane and the contact surface is 15° to 60°, a second included angle between the second reference plane and the contact surface is 45° to 90°, and the first included angle is smaller than the second included angle, the first included angle being an acute angle between the first reference plane and the contact surface, and the second included angle being an acute angle or a right angle between the second reference plane and the contact surface.

[0052] Please see Figure 6 , Figure 6 This is a schematic diagram of another posture for a legged robot during the low-lying support phase of its two lower limbs. Figure 6 The red dashed line at point C indicates the first reference plane, and the red dashed line at point D indicates the second reference plane. β represents the first included angle, and γ represents the second included angle. In this embodiment, the first included angle is, for example, 15°, 20°, 30°, 45°, 50°, or 60°, and the second included angle is, for example, 45°, 50°, 60°, 75°, 80°, or 90°. In addition to satisfying the above ranges, the first included angle and the second included angle must also satisfy that the first included angle is less than the second included angle, i.e., β < γ. For example, the first included angle and the second included angle are 15° and 45°, 30° and 60°, 45° and 75°, or 60° and 90°, respectively. The above values ​​are only used to illustrate the angular relationship between the reference planes; the actual angles are determined based on the robot's structural dimensions, current torso posture, and the support positions of the two lower limbs.

[0053] The first reference plane is used to describe the configuration of the first lower limb relative to the contact surface from a spatial perspective. For example... Figure 6 As shown, the first lower limb provides support to the contact surface via the knee joint. A first reference plane, intersecting the thigh, knee, and lower leg, is inclined relative to the contact surface, with a first angle β ranging from 15° to 60°. When the first angle decreases, the selected first reference plane becomes closer to being parallel to the contact surface; when the first angle increases, the inclination of the reference plane relative to the contact surface increases. These angular conditions, combined with the flexion state of the first lower limb and the knee contact position, describe a specific configuration in which the first lower limb participates in low-level support via the knee, and provide a postural basis for subsequent changes in the support position.

[0054] The second reference plane is used to describe the configuration of the second lower limb relative to the contact surface from a spatial perspective. For example... Figure 6As shown, the second lower limb provides support through its distal end and the contact surface. Simultaneously, the second reference plane intersecting with the thigh, knee, and lower leg forms a second angle γ between the reference plane and the contact surface, ranging from 45° to 90°. When the second angle approaches 90°, the selected second reference plane tends to be perpendicular to the contact surface; as the second angle decreases, the inclination of the reference plane relative to the contact surface decreases accordingly. The thigh and lower leg of the second lower limb maintain a flexion relationship adapted to the current support posture, and the extension direction of each part is determined by the specific joint posture. Thus, the angular condition of the second reference plane, combined with the distal support relationship, describes the spatial configuration of the second lower limb at this stage.

[0055] Furthermore, by making the first included angle smaller than the second included angle, the inclination of the first reference plane relative to the contact surface is limited to be less than that of the second reference plane. For example... Figure 6 As shown, the first lower limb, which provides knee support, and the second lower limb, which provides end-effector support, have different spatial postures, forming an asymmetrical low-end support configuration. In this configuration, the first lower limb uses the knee joint for support, while the second lower limb uses its end to receive the body load from another position. This allows the robot to bear the load with both lower limbs after the first upper limb is de-supported, and provides the posture basis for subsequently changing the first lower limb from knee joint support to end-effector support.

[0056] It should be noted that both the first and second lower limbs are three-dimensional spatial structures, and multiple reference planes can exist that intersect with the thigh, knee joint, and lower leg of the corresponding lower limbs. Figure 6 The first and second reference planes in the diagram represent one of the candidate planes. For the robot's posture at any given moment, if there exists a first reference plane and a second reference plane such that the first and second included angles are respectively within the aforementioned angle ranges, and simultaneously the first included angle is less than the second included angle, then the two lower limbs are considered to satisfy the aforementioned angle conditions of the reference planes. Each component of the first and second lower limbs is allowed to have a three-dimensional shape that spans the selected reference plane.

[0057] By utilizing the aforementioned settings and the angular range and magnitude relationship of the two reference planes, the spatial configuration of the low-lying support phase of the two lower limbs is further defined. This configuration, in conjunction with the support division of the first knee and the end of the second lower limb, allows the two lower limbs to jointly undertake the support task in different postures, and connects with the subsequent transition of the first lower limb support position. Based on the aforementioned body posture conditions when the first upper limb withdraws from support, this embodiment further defines the reference plane relationship between the two lower limbs during the low-lying support phase. Thus, the trunk posture when the upper limb withdraws and the spatial configuration when the two lower limbs bear the load are connected, specifically describing one implementation method of the coordination between the support of the first knee and the support of the end of the second lower limb.

[0058] In some embodiments, during the low-support phase of both lower limbs: the knee joint angle of the first lower limb is 30° to 90°, the knee joint angle of the second lower limb is 45° to 90°, and the knee joint angle of the first lower limb is less than or equal to the knee joint angle of the second lower limb.

[0059] In this embodiment, by limiting the knee joint angle of the two lower limbs as described above, the joint configuration when the first lower limb supports itself with its knee joint and the second lower limb supports itself with its lower extremity is further constrained. This allows the two lower limbs to participate in low-position support through different parts while maintaining flexion, and to connect with the subsequent transition of support positions. The smaller the knee joint angle, the greater the degree of flexion of the corresponding lower limb.

[0060] The knee angle of the first lower limb can be, for example, 30°, 45°, 60°, 75°, or 90°. Within this angle range, the first lower limb maintains a relatively pronounced flexion, allowing the knee joint to be in a relatively low position and provide support to the contact surface, while maintaining the hip at a height suitable for both lower limbs to share the body load. When the knee angle of the first lower limb is less than 30°, the degree of folding between the thigh and lower leg increases further, correspondingly reducing the space available for subsequent adjustments to the lower limb's distal position and for releasing knee support. When the knee angle of the first lower limb is greater than 90°, the first lower limb gradually tends to extend, and the body height and joint configuration in the knee-supported state also change significantly, making it unfavorable to maintain a low-supported posture for both lower limbs. Therefore, setting the knee angle of the first lower limb between 30° and 90° can balance the low-supported knee position with the joint mobility required for subsequent transitions from knee support to distal limb support.

[0061] The knee angle of the second lower limb can be, for example, 45°, 60°, 75°, or 90°. During the low-stance support phase, the second lower limb establishes support through its distal end against the contact surface, maintaining a flexed knee angle of 45° to 90°. This allows the second lower limb to retain some joint adjustment capability while bearing the body load, accommodating hip and trunk posture changes, and providing leeway for lower limb extension during the subsequent bipedal support phase. When the knee angle of the second lower limb is less than 45°, the degree of flexion is greater, further constricting the space between the distal end of the lower limb and the hip, potentially limiting the posture adjustment range when the second lower limb forms stable support through its distal end. When the knee angle of the second lower limb is greater than 90°, the extension of the second lower limb increases, correspondingly raising the overall robot position, potentially increasing the range of posture adjustments when maintaining the low-stance support state.

[0062] Furthermore, the knee angle of the first lower limb is less than or equal to the knee angle of the second lower limb. For example, the knee angles of the first and second lower limbs can be 30° and 45°, 45° and 60°, 60° and 75°, 75° and 90°, or both can be 45°, 60°, 75°, or 90°. When the knee angle of the first lower limb is less than that of the second lower limb, the first lower limb, which bears support through the knee joint, has a greater degree of flexion, while the second lower limb, which bears support through the distal end, is relatively extended. When the knee angles of both are equal, the two lower limbs have the same degree of knee flexion and can still form knee support and distal support respectively through their different positions and orientations. Thus, the two lower limbs form a mutually cooperating low-position support configuration according to their respective support points, so that after the first upper limb withdraws from support, the body load is jointly borne by the two lower limbs.

[0063] The aforementioned knee joint angle relationship can also be matched with the angle relationship between the two lower limb reference planes and the contact surface. The knee flexion degree of the first lower limb is greater than or equal to that of the second lower limb, and forms low-level support through the knee joint; the second lower limb forms support through its distal end. Combining the angular relationship between the first and second reference planes, the low-level support configuration of the two lower limbs is described from two aspects: the degree of joint flexion and the spatial relationship of the reference planes.

[0064] Based on this configuration, during the subsequent transition from the bi-leg low-support phase to the bi-foot support phase, the robot further adjusts the first lower limb, releasing support from the knee joint and engaging the distal end of the first lower limb in support. For example, while the distal end of the second lower limb remains supported, the robot adjusts the posture and distal position of the first lower limb to complete the transition from knee support to foot support, providing a foundation for further extension of both lower limbs and subsequent trunk elevation. When the first upper limb withdraws from support, the knee joint angle of the first lower limb satisfies the aforementioned condition of 30° to 120°; during the bi-leg low-support phase, the two lower limbs further satisfy the angle range and size relationship of this embodiment. By clearly defining the flexion configuration when the upper limb withdraws and when the bi-leg bears load, the first lower limb maintains a posture compatible with knee support, and the distal end of the second lower limb participates in bearing load, jointly connecting the subsequent support transition.

[0065] In some embodiments, during the ipsilateral upper and lower limb support phase, the elbow joint of the first upper limb makes support contact with the contact surface; the legged robot also includes a head connected to the upper torso, and when the instruction is executed by at least one processor, during the transition from the ipsilateral upper and lower limb support phase to the dual lower limb low support phase, the legged robot further causes: the elbow joint of the first upper limb to release support contact with the contact surface, and the elbow joint, head, and hip of the first upper limb to move away from the contact surface respectively; and the lower limb end of the second lower limb to move towards the lower limb end of the first lower limb and establish support contact with the contact surface, so that the legged robot enters the dual lower limb low support phase.

[0066] In this embodiment, during the ipsilateral upper and lower limb support phase, the first upper limb forms support contact with the contact surface via its elbow joint, while the first lower limb forms support contact with the contact surface via its knee joint. During the transition from the ipsilateral upper and lower limb support phase to the dual lower limb low-position support phase, the processor controls the elbow joint of the first upper limb to gradually release its support contact with the contact surface and coordinates the movement of the upper torso, the first upper limb, and the lower limbs, causing the elbow joint, head, and hip of the first upper limb to move away from the contact surface, respectively. As these parts gradually move away from the contact surface, the robot body gradually adjusts from a lower ipsilateral support posture to a posture suitable for both lower limbs to jointly bear the body load.

[0067] In this context, the release of the elbow joint from the contact surface means that the elbow joint no longer serves as the part of the first upper limb that transmits the supporting load to the contact surface. After the elbow joint releases its support, the first upper limb can adopt different support transition methods depending on the current body posture, which are not limited here. In one embodiment, the first upper limb can directly withdraw from the body support after the elbow joint releases its support. Specifically, as the elbow joint, head, and hip move away from the contact surface, other parts of the first upper limb no longer re-establish supporting contact with the contact surface, and the first upper limb as a whole gradually moves away from the contact surface. At the same time, the two lower limbs gradually bear the body load and establish a subsequent low-level support relationship through the knee joint of the first lower limb and the lower limb ends of the second lower limb. In another embodiment, the first upper limb can continue to provide temporary support through the upper limb ends after the elbow joint releases its support. Specifically, as the elbow joint of the first upper limb gradually moves away from the contact surface, the posture of the first upper limb can be adjusted so that the upper limb ends of the first upper limb establish supporting contact with the contact surface, thereby transferring the support part of the first upper limb from the elbow joint to the upper limb ends. During this support transition, the first upper limb can still bear part of the body load to facilitate the movement of the head and hips away from the contact surface. As the knee joint of the first lower limb and the lower limb ends of the second lower limb gradually form a support relationship capable of bearing the body load, the upper limb ends of the first upper limb are then controlled to release the support, allowing the first upper limb to exit the body support as a whole, and then enter the low-position support stage of both lower limbs.

[0068] Therefore, the release of support at the elbow joint of the first upper limb and the release of support at the entire first upper limb can occur in the same process or they can be sequential. When the first upper limb does not continue to support itself through other parts after the elbow joint releases support, the release of support at the elbow joint corresponds to the entire first upper limb withdrawing from support. When the first upper limb continues to bear support through its distal end after the elbow joint releases support, the state of the first upper limb withdrawing from support after the distal end further releases support is considered as the state of the first upper limb withdrawing from support at the entire first upper limb.

[0069] During the aforementioned changes in the first upper limb's supporting position, the processor also controls the movement of the second lower limb, causing its distal end to move closer to the distal end of the first lower limb. As the distal end of the second lower limb gradually approaches the distal end of the first lower limb, the joint posture of the second lower limb can be adjusted, allowing its distal end to reach a position suitable for establishing support with the contact surface and forming supporting contact. Thus, the second lower limb can gradually bear the load of the machine body and, together with the knee joint of the first lower limb, form a low-level support relationship between the two lower limbs. The movement of the distal end of the second lower limb closer to the distal end of the first lower limb means that the distance between the two distal ends decreases at least partially during this movement; the specific trajectory of the second lower limb and its final arrangement relative to the first lower limb are not limited. For example, the second lower limb can move towards the first lower limb from its original position to form a relatively parallel lower limb arrangement, or it can further extend towards the side of the first lower limb to form a cross arrangement, as long as the distal end of the second lower limb can move to a position suitable for participating in the low-level support relationship between the two lower limbs.

[0070] During the aforementioned transition, the load borne by the first upper limb gradually decreases as the knee joint of the first lower limb and the distal ends of the second lower limbs establish support. By moving the elbow joint, head, and hip away from the contact surface and gradually establishing support at the distal ends of the second lower limbs, the robot can gradually transfer the support load from the first upper limb to both lower limbs while lifting the body. When the first upper limb completely withdraws from support, and the knee joint of the first lower limb and the distal ends of the second lower limb respectively form support contact with the contact surface, the robot enters the dual-lower-limb support stage. This embodiment, following the aforementioned first knee participation in support and the corresponding trunk and lower limb posture conditions, specifically describes the actions of transitioning from this support configuration to dual-lower-limb support. By moving the head and hip away from the contact surface, the body position is adjusted; by moving the distal ends of the second lower limbs closer to the distal ends of the first lower limbs and establishing support, the load-bearing positions of the two lower limbs are adjusted. These actions, in conjunction with the change in the support state of the first upper limb, enable the front ipsilateral support configuration to transition to a configuration where the first knee and second foot jointly participate in support.

[0071] In some embodiments, when the instructions are executed by at least one processor, during the transition from the bipedal low-limb support phase to the bipedal support phase, the legged robot further causes: maintaining the lower limb tip of the second lower limb in support contact with the contact surface; controlling the knee joint of the first lower limb to release the support contact with the contact surface and move away from the contact surface; after the knee joint of the first lower limb releases the support contact with the contact surface, adjusting the posture of the lower limb tip of the first lower limb so that the foot area of ​​the lower limb tip moves toward the contact surface until the foot area establishes support contact with the contact surface, thereby enabling the legged robot to enter the bipedal support phase.

[0072] In this embodiment, during the transition from a low-lying support phase with both lower limbs to a support phase with both feet, the distal end of the second lower limb maintains support contact with the contact surface, serving as the continuous support point during this transition. Based on this, the support state of the first lower limb is adjusted. The processor controls the knee joint of the first lower limb to gradually reduce the support load it bears, releasing the support contact between the knee joint and the contact surface, and moving the knee joint away from the contact surface. As the knee joint of the first lower limb withdraws from support, the robot gradually transitions from a state where the knee joint of the first lower limb and the distal end of the second lower limb jointly participate in support to a state where the distal ends of both lower limbs jointly participate in support.

[0073] During the aforementioned transition, the distal end of the second lower limb maintains supporting contact with the contact surface, ensuring the robot retains a continuous lower limb support base even when the first lower limb changes its support position. The release of support contact at the knee joint of the first lower limb means that the knee joint no longer bears the supporting load used to maintain the robot's current posture. The knee joint of the first lower limb can gradually move away from the contact surface as the posture of the first lower limb adjusts, or it can briefly maintain non-supporting contact with the contact surface after the supporting load has been released, and then move away from the contact surface. After the knee joint of the first lower limb releases support contact with the contact surface, the processor further adjusts the posture of the first lower limb, gradually adjusting the distal end of the first lower limb from its current posture to a posture suitable for bearing the body load through the foot area. This posture adjustment can be achieved through the coordinated movement of one or more joints of the hip, knee, and ankle joints of the first lower limb, changing the position and orientation of the distal end of the first lower limb and gradually moving the foot area towards the contact surface. The specific movement trajectory of the first lower limb is not limited, as long as the first lower limb can be changed from a knee-supported state to a foot-supported state while maintaining the support of the lower limb end of the second lower limb.

[0074] During the adjustment process, the distal end of the first lower limb can first change its orientation relative to the contact surface and then move towards the contact surface; alternatively, it can continuously adjust its posture while moving towards the contact surface, gradually forming a suitable orientation for support in the foot area. Once the foot area contacts the contact surface, the joint state of the first lower limb can be further adjusted to form a supporting contact between the foot area and the contact surface capable of transmitting the body load. Thus, the supporting function of the first lower limb, borne by the knee joint, is converted to the supporting function borne by the distal end of the lower limb. It should be noted that during the low-position support stage of both lower limbs, the distal end of the first lower limb can be in a state separated from the contact surface or maintain non-supporting contact with the contact surface. In the conversion process of this embodiment, as the knee joint support of the first lower limb is released, the posture and load-bearing state of the distal end of the first lower limb are further adjusted so that the foot area eventually forms a supporting contact with the contact surface. Therefore, the conversion of the first lower limb from knee joint support to distal end support mainly reflects a change in the supporting part bearing the body load, and does not require the distal end of the first lower limb to necessarily be completely separated from the contact surface before establishing support.

[0075] Once the foot area of ​​the first lower limb establishes supporting contact with the contact surface, the distal ends of the first and second lower limbs respectively bear the load of the body, and the legged robot enters the bipedal support phase. Throughout the transition, the distal ends of the second lower limb continuously provide support, while the first lower limb sequentially completes the processes of knee joint withdrawal from support, knee joint lifting away from the contact surface, and distal end establishment of support. This establishes the bipedal support state without reintroducing support from the first upper limb, and provides a supporting foundation for subsequent lifting of the hips and upper torso by extending the two lower limbs.

[0076] In some embodiments, the legged robot further includes a head connected to the upper torso, wherein when the knee joint of the first lower limb disengages from the contact surface: along a direction perpendicular to the contact surface, the minimum distance between the head and the contact surface is a fifth distance, and the minimum distance between the hip and the contact surface is a sixth distance, and the ratio of the fifth distance to the sixth distance is greater than or equal to 1.5; the knee joint angle of the first lower limb is 30° to 90°, and the knee joint angle of the second lower limb is 30° to 90°; along a direction perpendicular to the contact surface, the projection area of ​​the portion of the first upper limb extending from the elbow joint to the end of the upper limb on the contact surface does not overlap with the projection area of ​​the upper torso on the contact surface.

[0077] Please see Figure 7 , Figure 7This is a schematic diagram of a legged robot's posture when the knee joint of the first lower limb disengages from the contact surface. In this embodiment, the knee joint disengaging from the contact surface means that the knee joint changes from a contact state to a state of separation from the contact surface; at this point, the support has been released and the part has left the contact surface. This embodiment uses this moment as the posture node for determining the distance between the head and hip and the ground, the degree of flexion of the two lower limbs, and the spatial position of the first upper limb.

[0078] Along the direction perpendicular to the contact surface, the minimum distance between the head and the contact surface is the fifth distance, and the minimum distance between the hips and the contact surface is the sixth distance. For example... Figure 7 As shown, d5 represents the fifth distance, and d6 represents the sixth distance, both determined by the minimum distance between the outer surfaces of the head and hips facing the contact surface and the contact surface, respectively. In this embodiment, the sixth distance is greater than 0, and the ratio of the fifth distance to the sixth distance is greater than or equal to 1.5, i.e., d5 / d6 ≥ 1.5. For example, this ratio can be 1.5, 1.8, 2, 2.5, or 3. For another example, when the fifth distance is 600mm and the sixth distance is 400mm, the ratio is 1.5; when the fifth distance is 750mm and the sixth distance is 300mm, the ratio is 2.5. The specific distances are determined based on the robot's overall dimensions, torso length, and current standing posture.

[0079] A ratio of the fifth distance to the sixth distance greater than or equal to 1.5 indicates that when the first lower limb knee joint leaves the contact surface, the minimum head-to-ground distance is at least 1.5 times the minimum hip-to-ground distance. For example... Figure 7 As shown, the head and hips have different ground clearances, creating a height difference between them. This ratio describes the head's position relative to the hips when the first lower limb's knee joint is off the ground, and together with the lower limb's flexion state, it defines the robot's posture during the support transition. When the sixth distance is the same, the larger this ratio, the greater the minimum ground clearance of the head, and the greater the difference between the minimum ground clearances of the head and hips. Based on the robot's posture illustrated, the robot adjusts its first lower limb after the first upper limb has exited support, providing a posture basis for its transition from knee support to lower limb end support.

[0080] When the knee joint of the first lower limb disengages from the contact surface, the included angle between the knee joints of the first and second lower limbs is 30° to 90°. For example, the included angles of the knee joints of the two lower limbs can be 30°, 45°, 60°, 75°, or 90°, respectively. They can be the same or different; this embodiment does not further limit their magnitude. Figure 7As shown, when the knee of the first lower limb leaves the ground, both lower limbs remain flexed. The second lower limb coordinates its joint configuration with the current position of the hip and torso, while the first lower limb adjusts the position and orientation of its distal end through joint movement. For example, while the distal end of the second lower limb provides support, the first lower limb coordinates to lift the knee off the ground and adjust its distal end posture, connecting to the double-footed support position. When the distal ends of both lower limbs are involved in support, the angle between the two knee joints can be increased, allowing both lower limbs to extend and lifting the hip and upper torso.

[0081] Furthermore, along a direction perpendicular to the contact surface, the projection area of ​​the portion of the first upper limb extending from the elbow joint to the distal end of the upper limb on the contact surface does not overlap with the projection area of ​​the upper torso on the contact surface. Specifically, the forearm, wrist, and distal end of the first upper limb extending distally from the elbow joint can be considered as the projection portion of the first upper limb, and this portion is projected onto the contact surface along the normal direction to obtain the first projection area; similarly, the upper torso can be projected onto the contact surface along the same direction to obtain the second projection area. When the first and second projection areas do not overlap, they can be considered non-overlapping. This projection relationship ensures that the distal end of the first upper limb is outside the projection area of ​​the upper torso when the first knee leaves the ground, clarifying its spatial configuration after exiting support and providing an initial avoidance relationship for subsequent body posture adjustments. Combined with the relative ground-leaning state of the head and hips and the knee flexion condition, a transitional posture is defined when the first lower limb transitions from knee support to distal support.

[0082] In actual movement, after the first upper limb exits the support, it can move laterally towards the upper torso through coordinated movements of the shoulder, elbow, or wrist joints, gradually moving the distal end of the first upper limb away from the projection area of ​​the upper torso on the contact surface. There are no restrictions on which side of the torso the first upper limb moves towards or what movement trajectory each joint adopts, as long as the portion of the first upper limb extending from the elbow joint to the distal end of the upper limb and the upper torso satisfy the aforementioned spatial relationship of non-overlapping projection areas when the knee joint of the first lower limb leaves the contact surface.

[0083] With the setup of this embodiment, at the critical moment when the knee joint of the first lower limb disengages from the contact surface, by positioning the head relatively high relative to the hip, maintaining a certain flexion state in both lower limbs, and ensuring that the distal end of the first upper limb, which has already exited support, is moved outside the projection area of ​​the upper torso, the robot can achieve a transitional posture suitable for further adjustment of the first lower limb. Based on this posture, the second lower limb continues to provide support for the lower limb end, while the first lower limb further completes the transition from knee support to lower limb end support, thereby connecting the aforementioned low-position support stage of both lower limbs with the subsequent support stage of both feet.

[0084] In some embodiments, when the instructions are executed by at least one processor, the legged robot, if in a fallen posture with the front or back of its torso facing the contact surface, in response to receiving a get-up trigger instruction, controls the upper torso to rotate, reducing the angle between the sagittal axis of the upper torso and the contact surface, and controls at least one part of the first upper limb and at least one part of the first lower limb to establish supporting contact with the contact surface, so that the legged robot enters the ipsilateral upper and lower limb support phase; wherein the angle is an acute angle or a right angle between the sagittal axis and the contact surface.

[0085] In this embodiment, when the legged robot is in a fallen posture with its torso facing the contact surface (either front or back), the processor, upon receiving a get-up trigger command, controls the robot to adjust its current posture, enabling it to enter the aforementioned ipsilateral upper and lower limb support phase. Specifically, the torso facing the contact surface corresponds to a prone position with the chest and abdomen facing the contact surface, while the torso facing the contact surface corresponds to a supine position with the back facing the contact surface. By adjusting these different fallen postures, the robot can enter a state where both the ipsilateral upper and lower limbs participate in support, seamlessly transitioning to the subsequent low-lying support phase with both lower limbs and the double-leg support phase.

[0086] Specifically, the processor controls the rotation of the upper torso relative to the contact surface, reducing the angle between the sagittal axis of the upper torso and the contact surface. The sagittal axis of the upper torso extends along its own anterior-posterior direction. When the front or back of the upper torso is basically facing the contact surface, the angle between this axis and the contact surface is close to 90°. As this angle decreases, the inclination of the sagittal axis relative to the contact surface decreases. Through lateral rotation, pitch rotation, or a combination of both of the upper torso, the direction of this axis relative to the contact surface is changed, and the angle decreases accordingly. The first upper limb and the first lower limb coordinate with the movement of the upper torso to adjust their position, so that the corresponding parts contact the contact surface and participate in the support of the body.

[0087] When the robot is initially in a supine position with its back facing the contact surface, the processor controls the upper torso to rotate towards the side where the first upper and lower limbs are located, and adjusts the position of the limbs on the same side accordingly. The first upper limb moves to a position where it can form support with the contact surface, and the first lower limb coordinates with the rotation of the torso to adjust its orientation and flexion state, so that the ipsilateral upper and lower limbs participate in the support. The upper torso changes from a posture with its back facing the contact surface to a lateral posture, and the angle between its sagittal axis and the contact surface decreases accordingly, thus entering the ipsilateral upper and lower limb support phase.

[0088] When the robot is initially in a prone position facing the contact surface, the processor coordinates the movement of the first upper limb and trunk, enabling the first upper limb to participate in support and assist in lifting the chest and abdomen. For example, the processor controls the first upper limb to adjust the shoulder and elbow joint postures, moving the upper limb end to a position where it can contact the contact surface and bear the robot's load, thus forming a supporting contact between the upper limb end and the contact surface. For the upper limb end already in contact with the contact surface, the processor adjusts the posture of the first upper limb to participate in the robot's support. During the process of the first upper limb participating in support through its end, the processor controls the elbow joint angle to increase, coordinating with trunk movement to increase the distance between the chest and abdomen and the contact surface. During the lifting process, the upper trunk changes its pitch posture, its anteroposterior direction changes from a direction closer to the normal to the contact surface to a direction inclined towards the contact surface, thus reducing the angle between the sagittal axis and the contact surface. Through this action, the first upper limb assists the chest and abdomen in moving away from the contact surface, providing space for the first lower limb to adjust its position. In coordination with the upper torso posture adjustment, the processor controls the first lower limb to change its configuration through hip and knee joint movements, causing the thigh to rotate relative to the hip and the lower leg to flex relative to the thigh. Through these movements, the first lower limb adjusts the positional relationship between the knee and hip, ensuring the knee joint forms supporting contact with the contact surface. For example, during the process of the first upper limb assisting in lifting the chest and abdomen, the first lower limb flexes and retracts, adjusting its knee to a position capable of bearing the machine's load. If the knee is already in contact with the contact surface, it coordinates with hip and torso movements to adjust its stress state, enabling the knee to participate in supporting the machine.

[0089] Through the aforementioned coordination, the robot in a prone position uses its first upper limb to assist in lifting its torso, and utilizes the knee of its ipsilateral first lower limb to participate in load-bearing, forming a ipsilateral upper and lower limb support state. Depending on the current limb position, the upper torso can also rotate laterally, positioning the ipsilateral upper and lower limbs in a suitable position for joint support. Upper limb support, torso rotation, and lower limb configuration adjustment can overlap, and the first upper and lower limbs can participate in support sequentially or simultaneously. The process of using the distal end of the upper limb and the knee for support is a specific implementation method for entering the ipsilateral upper and lower limb support stage from a prone position.

[0090] The trunk rotation direction and limb movement trajectory corresponding to the two initial postures may differ, but both achieve a shared support relationship by adjusting the orientation of the upper trunk, reducing the angle between the sagittal axis and the contact surface, and engaging the ipsilateral first upper and lower limbs in support. The contact state between the trunk and other body parts and the contact surface changes with the movement. When the first upper and lower limbs jointly participate in support, an ipsilateral upper and lower limb support state is formed, which connects with the subsequent movement of the first upper limb withdrawing from support and both lower limbs participating in low-position support. This allows different falling postures—face-down and back-down—to be integrated into a unified support phase transition process, reducing the dependence of subsequent rising movements on the initial lying direction.

[0091] In some embodiments, the legged robot further includes a vision sensor; when the instructions are executed by at least one processor, before controlling the legged robot to perform a sequence of standing movements, the legged robot also: acquires environmental visual information collected by the vision sensor, determines available support areas on both sides of the torso based on the environmental visual information, the available support areas being areas where the limbs of the legged robot establish support contact with the contact surface; and determines a first upper limb and a first lower limb from both sides of the torso based on the location and extent of the available support areas.

[0092] In this embodiment, the legged robot also includes a vision sensor. Before controlling the legged robot to execute a sequence of standing movements, the processor acquires environmental visual information collected by the vision sensor and determines the available support areas on both sides of the torso based on the environmental visual information. The available support area can be understood as the area that the robot's limbs can reach and establish support contact with the contact surface. The processor can determine the side more suitable for establishing a support relationship between the upper and lower limbs on the same side based on the position of the available support area relative to the sides of the torso, the range of the available support area, and the robot's current posture, and designate the upper and lower limbs corresponding to that side as the first upper limb and the first lower limb, respectively.

[0093] Environmental visual information can include the spatial distribution of contact surfaces around the robot, obstacle occupancy, and the range of areas available for limb contact. Based on this information, the processor can determine whether there are areas on both sides of the torso where the upper and lower limbs can establish support contact. For example, when there is a large continuous contact surface on one side of the torso, while an obstacle occupies the corresponding area on the other side, the side with the larger available support area can be designated as the side containing the first upper and lower limbs, allowing the robot to preferentially establish ipsilateral upper and lower limb support relationships towards that side.

[0094] For example, when the robot is in a fallen position with its back facing the contact surface, it can obtain environmental information on both sides of its body through visual sensors. If the left side of the robot's contact surface is relatively open, providing enough space for the first upper limb and the ipsilateral lower limb to establish support contact, while the right side has walls, boxes, or other obstacles that limit the available support area, the processor can select the left side as the side to establish the ipsilateral upper and lower limb support relationship, and designate the left upper limb and left lower limb as the first upper limb and first lower limb, respectively. Subsequently, the robot can adjust its torso and limb posture in the corresponding direction to establish support contact between the left upper limb and left lower limb, and enter the ipsilateral upper and lower limb support phase.

[0095] For example, when a robot is in a fallen position with its back facing the contact surface, and there is an obstacle on the left while there is a large usable support area on the right, the right upper limb and right lower limb can be designated as the first upper limb and the first lower limb, respectively. Thus, the same sequence of getting-up actions can be executed according to the left-right mirror image of the robot's surrounding environment, without needing to pre-determine which upper limb or lower limb will always be the first upper limb or the first lower limb.

[0096] In another example, when the robot is in a fallen posture facing the contact surface, the processor can also select the side to establish the ipsilateral upper and lower limb support relationship based on the environmental visual information on both sides of the torso. For example, if the robot's chest and abdomen are facing the contact surface, and the left side is close to furniture, a wall, or other objects, making it difficult for the left upper or lower limb to form a sufficient support area, while the right side has a relatively open contact surface, then the right upper and lower limbs can be selected as the first upper and lower limbs. When the robot flips from a posture facing the contact surface to a side posture, it can adjust to the right accordingly, so that the right upper and lower limbs gradually form support contact with the contact surface, thereby entering the aforementioned ipsilateral upper and lower limb support stage.

[0097] For example, when the robot is in a fallen posture facing the contact surface, and there is an obstacle on the right side of the robot and a large usable support area on the left side, the left upper limb and left lower limb can be designated as the first upper limb and first lower limb, and the robot can be adjusted to the left to complete the corresponding posture adjustment. Thus, the determination of the first upper limb and first lower limb can dynamically change according to the robot's current lying direction and the surrounding environment.

[0098] In some cases, available support areas may exist on both sides of the robot. In this situation, the processor can further compare the position and range of the available support areas on both sides. For example, the side with a larger continuous area, closer to the current position of the corresponding limb, or easier to establish support contact with the limb can be preferentially selected as the side where the first upper limb and first lower limb are located. If the available support areas on both sides meet the requirements for standing up, one side can be determined according to preset selection rules so that the robot can execute the subsequent standing action sequence in the corresponding direction.

[0099] In other cases, obstacles exist on both sides of the robot, but one side still retains an area where the upper and lower limbs can establish supporting contact. For example, one side of the robot may have only a small obstacle located outside the upper limb, while the area near the torso on that side still has an area where the upper and lower limbs can make contact; the other side may have a larger obstacle covering the main support position. In this case, the side that still has the support conditions can be selected based on the location and extent of the remaining usable support areas on both sides, and the corresponding first upper limb and first lower limb can be determined.

[0100] Therefore, by determining the available support areas on both sides of the torso based on environmental visual information before performing the standing-up action, the selection of the first upper limb and the first lower limb can be adapted to the robot's current surrounding environment. Regardless of whether the robot is in a fallen posture facing the contact surface or its back is facing the contact surface, and regardless of whether there are obstacles on the left and right sides of the robot, the side with suitable support conditions can be selected first to establish a support relationship between the upper and lower limbs on the same side. Then, the subsequent standing-up process is completed according to the aforementioned ipsilateral upper and lower limb support stage, the low-position support stage of both lower limbs, and the support stage of both feet.

[0101] In the embodiments of this application, multiple control actions are described for the same action stage. Unless one control action is explicitly specified to be executed before or after another control action, the multiple control actions can be executed in a preset order, or at least partially synchronously or overlappingly.

[0102] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0103] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between apparatuses or units, and may be electrical, mechanical, or other forms.

[0104] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0105] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0106] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A legged robot, characterized in that, include: The torso, including the upper torso and hips that are rotated and connected to each other; Two upper limbs and corresponding upper limb ends, the two upper limbs being connected to the upper torso; Two lower limbs and corresponding lower limb ends, the two lower limbs being connected to the hip; wherein, the first upper limb of the two upper limbs and the first lower limb of the two lower limbs are located on the same side of the sagittal plane of the upper trunk, and the second lower limb of the two lower limbs and the first lower limb are located on different sides of the sagittal plane of the upper trunk; At least one processor; and, At least one storage medium storing instructions that, when executed by the at least one processor, cause the legged robot to: In response to receiving a stand-up trigger command, the legged robot is controlled to execute a stand-up action sequence, which includes, in sequence, a support phase of the same side upper and lower limbs, a low support phase of both lower limbs, and a support phase of both feet. During the ipsilateral upper and lower limb support phase, at least one part of the first upper limb and at least one part of the first lower limb are controlled to make contact with the contact surface support. Control the first upper limb to release the support contact with the contact surface, so that the legged robot enters the dual lower limb low support stage. In the dual lower limb low support stage, the knee joint of the first lower limb and the lower limb end of the second lower limb respectively make support contact with the contact surface. Control the knee joint of the first lower limb to release its support contact with the contact surface, and control the lower limb end of the first lower limb to make support contact with the contact surface, so that the legged robot enters the bipedal support phase. In the bipedal support phase, the lower limb ends of the two lower limbs respectively make support contact with the contact surface.

2. The legged robot according to claim 1, characterized in that, During the ipsilateral upper and lower limb support phase: The angle between the sagittal axis of the upper torso and the contact surface is 0° to 60°, and the angle is the acute angle between the sagittal axis and the contact surface; The elbow joint, wrist joint, or distal end of the first upper limb is in support contact with the contact surface, and the knee joint of the first lower limb is in support contact with the contact surface. The included angle of the knee joint of the first lower limb is 30° to 120°. The plane that intersects the thigh, knee joint and calf of the first lower limb simultaneously is used as the first reference plane, and the angle between the first reference plane and the contact surface is 0° to 75°.

3. The legged robot according to claim 1, characterized in that, The legged robot also includes a head connected to the upper torso, which, when the first upper limb releases its supporting contact with the contact surface: The angle between the sagittal axis of the upper torso and the contact surface is 0° to 75°, and the angle is the acute angle between the sagittal axis and the contact surface; Along a direction perpendicular to the contact surface, the minimum distance between the head and the contact surface is a first distance, and the minimum distance between the hip and the contact surface is a second distance, wherein the ratio of the first distance to the second distance is greater than or equal to 1; The knee joint angle of the first lower limb is between 30° and 120°.

4. The legged robot according to claim 3, characterized in that, During the low-lying support phase of the lower limbs: The minimum distance between the knee joint of the first lower limb and the knee joint of the second lower limb is the third distance, and the minimum distance between the lower limb tip of the first lower limb and the lower limb tip of the second lower limb is the fourth distance. The ratio of the third distance to the fourth distance is greater than or equal to 1.

5.

5. The legged robot according to claim 3, characterized in that, During the low-lying support phase of the lower limbs: A plane that intersects simultaneously with the thigh, knee joint, and calf of the first lower limb is used as a first reference plane, and a plane that intersects simultaneously with the thigh, knee joint, and calf of the second lower limb is used as a second reference plane. The first included angle between the first reference plane and the contact surface is 15° to 60°, and the second included angle between the second reference plane and the contact surface is 45° to 90°. The first included angle is smaller than the second included angle. The first included angle is an acute angle between the first reference plane and the contact surface, and the second included angle is an acute angle or a right angle between the second reference plane and the contact surface.

6. The legged robot according to claim 3, characterized in that, During the low-lying support phase of the lower limbs: The knee joint angle of the first lower limb is 30° to 90°, the knee joint angle of the second lower limb is 45° to 90°, and the knee joint angle of the first lower limb is less than or equal to the knee joint angle of the second lower limb.

7. The legged robot according to claim 2, characterized in that, During the ipsilateral upper and lower limb support phase, the elbow joint of the first upper limb makes support contact with the contact surface; The legged robot also includes a head connected to the upper torso, and when the instructions are executed by the at least one processor, during the transition from the ipsilateral upper and lower limb support phase to the bilateral lower limb low-position support phase, the legged robot further causes: Control the elbow joint of the first upper limb to release it from the support contact with the contact surface, and move the elbow joint of the first upper limb, the head and the hip respectively away from the contact surface; The lower limb of the second lower limb is controlled to move towards the lower limb of the first lower limb and establish a supporting contact with the contact surface, so that the legged robot enters the low-position support stage of the two lower limbs.

8. The legged robot according to claim 1, characterized in that, When the instruction is executed by the at least one processor, during the transition from the bipedal low-limb support phase to the bipedal support phase, the legged robot also causes: Maintain the supporting contact between the lower limb end of the second lower limb and the contact surface, control the knee joint of the first lower limb to release the supporting contact with the contact surface, and move it away from the contact surface; After the knee joint of the first lower limb releases its supporting contact with the contact surface, the posture of the lower limb end of the first lower limb is adjusted so that the foot area of ​​the lower limb end moves toward the contact surface until the foot area establishes supporting contact with the contact surface, so that the legged robot enters the bipedal support phase.

9. The legged robot according to claim 1, characterized in that, The legged robot also includes a head connected to the upper torso, which is present when the knee joint of the first lower limb disengages from the contact surface: Along a direction perpendicular to the contact surface, the minimum distance between the head and the contact surface is the fifth distance, the minimum distance between the hip and the contact surface is the sixth distance, and the ratio of the fifth distance to the sixth distance is greater than or equal to 1.5; The knee joint angle of the first lower limb is 30° to 90°, and the knee joint angle of the second lower limb is 30° to 90°. Along a direction perpendicular to the contact surface, the projection area of ​​the portion of the first upper limb extending from the elbow joint to the end of the upper limb on the contact surface does not overlap with the projection area of ​​the upper torso on the contact surface.

10. The legged robot according to claim 1, characterized in that, When the instructions are executed by the at least one processor, the legged robot also causes: If the legged robot is in a fallen posture and the front or back of the torso is facing the contact surface, in response to receiving the get-up trigger command, the upper torso is controlled to rotate, so that the angle between the sagittal axis of the upper torso and the contact surface is reduced, and at least one part of the first upper limb and at least one part of the first lower limb are controlled to establish support contact with the contact surface respectively, so that the legged robot enters the ipsilateral upper and lower limb support phase; Wherein, the included angle is an acute angle or a right angle between the sagittal axis and the contact surface.

11. The legged robot according to any one of claims 1 to 10, characterized in that, The legged robot also includes a vision sensor; when the instructions are executed by the at least one processor, before controlling the legged robot to execute the standing-up sequence, the legged robot also causes the legged robot to: The system acquires environmental visual information collected by the visual sensor, and determines the available support areas on both sides of the torso based on the environmental visual information. The available support areas are the areas where the limbs of the legged robot can establish support contact with the contact surface. Based on the location and extent of the available support area, the first upper limb and the first lower limb are determined from both sides of the torso.

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