Patent Description:
At present, increasingly more legged robots are designed and applied in daily life. In a process of designing a legged robot, it is required to consider how to control the legged robot to walk and move normally in different environments, to solve the problem of unstable walking and moving of the legged robots that is caused by an unknown environment.

In the conventional art, a pressure sensor is installed on a foot of a legged robot, to sense the magnitude and direction of a pressure contacted by the foot of the legged robot, and a walking mode of the legged robot is adjusted according to the detected information of the pressure, for example, a stride or a walking direction is adjusted, to realize normal walking of the legged robot in some unknown environments.

However, in a process of practically applying the solutions in the conventional art, there is a problem that the legged robot cannot be controlled to move normally in some unknown environments by adjusting foot postures because the legged robot has a little perception information about the environment, resulting in limited application scenarios of the legged robot.

The prior art document No. <CIT> provides a locomotion control system to input the quantity of materials in the real world, such as the quantity of motion state of a robot, external force and external moment, and environmental shapes, measured with sensors or the like. By integrating all calculations for maintaining a balance of the body into a single walking-pattern calculating operation, both a locomotion generating function and an adaptive control function are effectively served, the consistency of dynamic models is ensured, and interference between the dynamic models is eliminated. Calculations for generating a walking pattern of the robot can be performed in an actual apparatus and in real time in a manner in which parameters, such as a boundary condition concerning the quantity of motion state, external force and external moment, and the trajectory of the sole, are settable.

The prior art document No. XP11770716A provides a reactive locomotion strategy for torque controllable quadruped robots based on sensitized feet. Since the present approach works without exteroceptive sensing, it is robust against degraded vision. Inertial and force/torque sensors implemented in specially designed feet with articulated passive ankle joints measure the local terrain inclination and interaction forces. The proposed controller exploits the contact null-space in order to minimize the tangential forces to prevent slippage even in case of extreme contact conditions.

The prior art document No. <CIT> provides a foot mechanism with high load bearing of a foot type robot, belongs to the technical field of robots, and relates to a foot mechanism with high load bearing of the foot type robot, which has a favorable shock absorption property and a favorable self-resetting property. The foot mechanism of the foot type robot adopts conical springs to realize the shock absorption property and the self-resetting property of the foot mechanism and adopts a piston sliding structure to realize a shock absorption displacement stroke, and the requirements for the high load bearing, the good shock absorption property and the good self-resetting property of the foot mechanism are met. In the foot mechanism, a slip-proof rubber foot bottom pad is bonded on a foot bottom plate, so that a slip phenomenon in an advance process is avoided; spring seats are mounted in grooves of the foot bottom plate, and the conical springs are mounted between the spring seats and lower bearing pad rings; a ball head rod is mounted in an arc-shaped groove of the foot bottom plate, a ball pair structure is constituted by the ball head rod and the arc-shaped groove, and the ball pair is in clearance fit. According to the foot mechanism disclosed by the invention, the requirements for the high load bearing, the good shock absorption property and the good self-resetting property of the foot mechanism are met, and the foot mechanism is simple in integral structure, low in gravity center design, and safe and reliable.

The prior art document No. <CIT> provides a control device of a legged mobile robot, wherein a state amount error (for example, an error of a vertical position of a body <NUM>), which is a difference between an actual state amount and a state amount of a desired gait related to a translational motion in a predetermined direction (for example, a translational motion in a vertical direction) of a legged mobile robot <NUM>, is determined, and then a desired motion of the desired gait is determined such that the state amount error approaches zero. The desired motion is determined using a dynamic model by additionally inputting a virtual external force determined on the basis of the state amount error to the dynamic model for generating desired gaits. At the same time, a desired floor reaction force of the robot <NUM> is corrected on the basis of a state amount error of zero, and compliance control is carried out to make the motion and the floor reaction force of the robot <NUM> follow the desired motion and the desired floor reaction force of the desired gait.

A leg assembly and device for a robot are provided according to this application. The technical solutions are described as follows.

In an aspect, a leg assembly for a robot is provided, the leg assembly <NUM> includes: a connection assembly <NUM> and a plantar assembly <NUM>. The connection assembly <NUM> is configured to connect the leg assembly <NUM> with an upper body <NUM> of the robot. The plantar assembly <NUM> includes a plantar plate <NUM>, a first force sensor <NUM>, a distance sensor <NUM>, and a posture sensor <NUM>. The connection assembly <NUM> includes a second force sensor <NUM> and a shank connector <NUM>. The first force sensor <NUM>, the distance sensor <NUM>, the posture sensor <NUM>, and the second force sensor <NUM> are electrically connected to a control unit <NUM>. The first force sensor <NUM> is configured to detect a normal reaction force applied to the plantar plate <NUM> when the plantar plate (<NUM>) is in contact with an obstacle. The distance sensor <NUM> is configured to detect a distance between the plantar plate <NUM> and the obstacle in real time. The posture sensor <NUM> is configured to detect a spatial orientation of the plantar plate <NUM>. The second force sensor <NUM> is configured to detect a resultant force of reaction forces applied to the plantar plate <NUM> when the plantar plate (<NUM>) is in contact with the obstacle. The plantar plate <NUM> is a metal structure part with a void or a groove. The first force sensor <NUM>, the distance sensor <NUM>, and the posture sensor <NUM> are connected to the control unit <NUM> via connection wires passing through the void or the groove of the metal structure part. A bottom and an outer side of the metal structure part are cladded with plantar rubber <NUM>. The first force sensor <NUM> is an ionic thin-film force sensor. The ionic thin-film force sensor is arranged between the plantar rubber <NUM> and the bottom of the metal structure part, and the ionic thin-film force sensor is of a ring shape. The distance sensor <NUM> is a thin-film distance sensor. The thin-film distance sensor is centrally arranged between the plantar rubber <NUM> and the bottom of the metal structure part. A thickness of the plantar rubber <NUM> at a portion under the thin-film distance sensor is smaller than a thickness of the plantar rubber <NUM> at another portion.

In an embodiment, the plantar assembly <NUM> is connected with the connection assembly <NUM> through a joint assembly <NUM>. The joint assembly <NUM> includes a joint ball socket <NUM>, a ball joint <NUM>, and an elastic assembly <NUM>. The plantar plate <NUM> is configured to drive, in response to a reaction force from a contact surface, the joint ball socket <NUM> to rotate relative to the ball joint <NUM> with three degrees of freedom, to adapt the plantar plate to fit the contact surface.

In an embodiment, the elastic assembly <NUM> includes a conical return spring. The conical return spring is configured to be in a passively compressed state in a case that the plantar plate <NUM> is in contact with the obstacle. The conical return spring is further configured to release stored energy in a case that the plantar plate <NUM> is separated from the obstacle, to drive the plantar plate <NUM> to restore to an initial state.

In an embodiment, the joint ball socket <NUM> includes a limiting structure. The joint ball socket with the limiting structure are provided with low front and rear edges and high left and right edges.

In an embodiment, the posture sensor <NUM> is arranged in the groove of the metal structure part.

In an embodiment, the elastic assembly <NUM> includes a conical return spring. The conical return spring is sleeved on a periphery of the ball joint <NUM>, and a lower end of the conical return spring is connected to the plantar plate <NUM>, and an upper end of the conical return spring is connected to the shank connector <NUM>.

In an embodiment, the shank connector <NUM> is a hollow triangular prism connector. A lower end of the shank connector <NUM> is connected to the second force sensor <NUM> by using a flange.

In an embodiment, the posture sensor <NUM> is an inertial measurement unit (IMU).

In an embodiment, the second force sensor <NUM> is a six-axis force sensor.

In an embodiment, the control unit <NUM> is arranged in the upper body <NUM> of the robot.

In an embodiment, a contact surface of the plantar plate <NUM> with the environment is a circular plane.

In an embodiment, an encoder is arranged on the ball joint <NUM>.

In an aspect, a leg device for a robot is provided, the device includes an upper body <NUM> of the robot and the leg assembly <NUM>.

The technical solutions according to this application may realize the following beneficial effects. In the solutions in the embodiments of this application, by installing a first force sensor, a distance sensor, a posture sensor, and a second force sensor in a leg assembly for a robot, the leg assembly can perform comprehensive detection of a contact environment, and upload detection results of the sensors to a control unit, so that the control unit comprehensively controls the robot based on the detection results of the sensors. With the solutions in this application, rather than obtaining a measurement result in a single aspect through detection of a single pressure sensor, more types and quality of perception information about the environment are obtained by the robot, so that the control unit can obtain a more comprehensive detection result, and control the robot to move through the leg assembly according to the detection result, thereby greatly improving a control effect on the leg assembly of the robot, thus extending application scenarios of a legged robot.

The drawings herein are included in this specification and form a part of this specification, illustrate embodiments consistent with the present disclosure, and are used to explain the principles of the present disclosure together with this specification.

Exemplary embodiments are described in detail herein, and examples of the exemplary embodiments are shown in the drawings. When the following description involves the drawings, unless otherwise indicated, the same numerals in different drawings represent the same or similar elements. The following exemplary embodiments do not represent all embodiments that are consistent with this application. On the contrary, the exemplary embodiments are merely examples of devices and methods that are described in detail and that are consistent with the claims and some aspects of this application.

It is to be understood that, "several" mentioned in this specification means one or more, and "plurality of" means two or more. And/or describes an association relationship for describing associated objects and represents that three relationships may exist. For example, A and/or B may represent the following three cases: only A exists, both A and B exist, and only B exists. The character "/" in this specification generally indicates an "or" relationship between the associated objects.

For ease of understanding, several terms involved in this application are explained below.

Artificial intelligence (AI) indicates a theory, method, technology, and application system that uses a digital computer or a machine controlled by the digital computer to simulate, extend, and expand human intelligence, perceive an environment, obtain knowledge, and use knowledge to obtain an optimal result. In other words, the Al indicates a comprehensive technology of computer science, which attempts to understand essence of intelligence and produces a new intelligent machine that can respond in a manner similar to human intelligence. The Al is used to study the design principles and implementation methods of various intelligent machines, to enable the machines to have the functions of perception, reasoning, and decision-making.

The Al technology involves a comprehensive discipline, and relates to a wide range of fields including both hardware-level technologies and software-level technologies. The basic Al technologies generally include technologies such as a sensor, a dedicated Al chip, cloud computing, distributed storage, a big data processing technology, an operating/interaction system, and electromechanical integration. The Al software technologies mainly include several major directions such as a computer vision technology, a speech processing technology, a natural language processing technology, and machine learning/deep learning.

With the research and progress of the Al technology, the Al technology is studied and applied in many fields such as a common smart home, a smart wearable device, a virtual assistant, a smart speaker, smart marketing, unmanned driving, automatic driving, an unmanned aerial vehicle, a robot, smart medical care, and smart customer service. It is believed that with the development of technologies, the Al technology will be applied to more fields, and play an increasingly important role.

<FIG> is a constructional diagram of a leg assembly for a robot according to an exemplary embodiment of this application. As shown in <FIG>, the leg assembly <NUM> includes: a connection assembly <NUM> and a plantar assembly <NUM>. The connection assembly <NUM> is configured to connect the leg assembly <NUM> with an upper body <NUM> of the robot. The plantar assembly <NUM> includes a plantar plate <NUM>, a first force sensor <NUM>, a distance sensor <NUM>, and a posture sensor <NUM>. The connection assembly <NUM> includes a second force sensor <NUM> and a shank connector <NUM>. The first force sensor <NUM>, the distance sensor <NUM>, the posture sensor <NUM>, and the second force sensor <NUM> are electrically connected to a control unit <NUM>. The first force sensor <NUM> is configured to detect a normal reaction force applied to the plantar plate <NUM> when the plantar plate <NUM> is in contact with an obstacle. The distance sensor <NUM> is configured to detect a distance between the plantar plate <NUM> and the obstacle in real time. The posture sensor <NUM> is configured to detect a spatial orientation of the plantar plate <NUM>. The second force sensor <NUM> is configured to detect a resultant force of reaction forces applied to the plantar plate <NUM> when the plantar plate <NUM> is in contact with the obstacle.

Therefore, by installing a first force sensor, a distance sensor, a posture sensor, and a second force sensor in a leg assembly for a robot, the leg assembly can perform comprehensive detection of a contact environment, and upload detection results of the sensors to a control unit, so that the control unit comprehensively controls the robot based on the detection results of the sensors. With the solutions in this application, rather than obtaining a measurement result in a single aspect through detection of a single pressure sensor, more types and quality of perception information about the environment are obtained by the robot, so that the control unit can obtain a more comprehensive detection result, and control the robot to move through the leg assembly according to the detection result, thereby greatly improving a control effect on the leg assembly of the robot, thus extending application scenarios of a legged robot.

<FIG> is a schematic structural diagram of a leg assembly according to an exemplary embodiment of this application. As shown in <FIG>, the leg assembly <NUM> includes: a connection assembly <NUM> and a plantar assembly <NUM>. The connection assembly <NUM> is configured to connect the leg assembly <NUM> with an upper body <NUM> of the robot. The plantar assembly <NUM> includes a plantar plate <NUM>, a first force sensor <NUM>, a distance sensor <NUM>, and a posture sensor <NUM>. The connection assembly <NUM> includes a second force sensor <NUM> and a shank connector <NUM>. The first force sensor <NUM>, the distance sensor <NUM>, the posture sensor <NUM>, and the second force sensor <NUM> are electrically connected to a control unit <NUM>. The first force sensor <NUM> is configured to detect a normal reaction force applied to the plantar plate <NUM> when the plantar plate <NUM> is in contact with an obstacle. The distance sensor <NUM> is configured to detect a distance between the plantar plate <NUM> and the obstacle in real time. The posture sensor <NUM> is configured to detect a spatial orientation of the plantar plate <NUM>. The second force sensor <NUM> is configured to detect a resultant force of reaction forces applied to the plantar plate <NUM> when the plantar plate <NUM> is in contact with the obstacle.

In an embodiment, the plantar assembly <NUM> is connected with the connection assembly <NUM> through a joint assembly <NUM>. The control unit <NUM> may be arranged in the leg assembly <NUM>. Alternatively, the control unit <NUM> may be arranged in the upper body <NUM> of the robot.

For example, <FIG> is a schematic cross-sectional structural diagram of the plantar assembly <NUM> in the embodiment of this application. As shown in <FIG>, the plantar assembly <NUM> is an assembly of the robot that directly contacts the environment. Different degrees of contact between the environment and the plantar assembly <NUM> may be reflected by reaction forces of different magnitudes and different directions applied by the environment to the plantar assembly <NUM>. In order to accurately measure an influence generated by the environment on the plantar assembly <NUM>, the plantar assembly <NUM> needs to install a sensor configured to measure information generated by the robot on the contact with the environment. The plantar assembly <NUM> may include: a plantar plate <NUM>, a first force sensor <NUM>, a distance sensor <NUM>, a posture sensor <NUM>, a seal ring <NUM>, and plantar rubber <NUM>.

In an embodiment, a contact surface of the plantar plate <NUM> with the environment is a circular plane. The circular plane may provide an isotropic contact condition, and facilitates mechanical modeling of a plantar contact force by using a classical Coulomb friction cone model. is a static friction force, is a coefficient of static friction, and is a normal contact force.

In an embodiment, to increase a friction coefficient of the plantar plate, provide a certain degree of buffering to an impact to the robot when the robot sets foot on the ground, and protect the plantar plate <NUM>. In addition, a bottom and an outer side of the plantar plate <NUM> are cladded with a rubber pad as the plantar rubber <NUM>.

In an embodiment, the first force sensor <NUM> is arranged between the bottom of the plantar plate <NUM> and the plantar rubber <NUM>. The first force sensor <NUM> may be an ionic thin-film force sensor, and is arranged between the bottom of the plantar plate <NUM> and the plantar rubber <NUM> and is of a ring shape. The ionic thin-film force sensor may be configured to measure a normal contact force between the obstacle in contact with the plantar plate <NUM> and the plantar plate <NUM>. By using the ionic thin-film force sensor, the accuracy of measuring the normal contact force can be improved, a space occupied by the force sensor of the plantar assembly <NUM> is reduced, and a weight of the plantar assembly <NUM> is also reduced.

In an embodiment, the distance sensor <NUM> is arranged between the lower part of the plantar plate <NUM> and the plantar rubber <NUM> at the bottom. The distance sensor <NUM> is arranged in a central area of the first force sensor <NUM> that is of a ring shape, and the distance sensor <NUM> may be a thin-film distance sensor. The thin-film distance sensor may be configured to measure a distance between the plantar rubber <NUM> and the obstacle when the plantar plate <NUM> is being close to or away from the obstacle in the environment.

In an embodiment, a thickness of the plantar rubber <NUM> at a portion under the thin-film distance sensor is smaller than a thickness of the plantar rubber <NUM> at another portion of the plantar assembly <NUM>. By reducing the thickness of the portion of the plantar rubber <NUM> under the thin-film distance sensor, the thin-film distance sensor may obtain a better measurement effect and have a large measurement distance. Measured values of a distance between the plantar rubber <NUM> and the external environment and the normal contact force that are detected by the thin-film distance sensor and the ionic thin-film force sensor are all uploaded to a control unit <NUM>, so that a control effect of the control unit <NUM> on the leg assembly <NUM> can be improved.

In an embodiment, the posture sensor <NUM> is an inertial measurement unit (IMU). The IMU is a device configured to measure a three-axis posture angle and an acceleration of an object.

In an embodiment, postures of a coordinate system of the IMU relative to a coordinate system of the plantar plate <NUM> may be arbitrarily arranged, and after the arranged IMU and plantar plate are calibrated, a three-axis posture angle of the plantar plate <NUM> may be measured as a posture measurement value. A spatial orientation of the plantar plate <NUM> is determined based on the posture measurement value.

In an embodiment, the coordinate system of the IMU and the coordinate system of the plantar plate <NUM> are aligned. When the coordinate system of the IMU and the coordinate system of the plantar plate <NUM> are aligned, the arranged IMU and plantar plate may not be calibrated, and the posture measurement value is directly measured through the IMU. The IMU measures Euler angles of the plantar plate <NUM> in a geographic absolute coordinate system. The Euler angles represent a series of three-dimensional basic rotation angles, that is, a series of rotation angles around coordinate axes of a coordinate system. For example, an angle is first formed by rotating around a z-axis, an angle is formed by rotating around an x-axis, and an angle is formed by rotating around a z-axis. According to the obtained Euler angles, the spatial orientation of the plantar plate <NUM> is obtained.

In an embodiment, a shock absorbing gasket is arranged between the posture sensor <NUM> and a metal structure part (the plantar plate <NUM>), to reduce interference on measurement of the posture sensor <NUM> or physical damage to the posture sensor <NUM> caused by a landing impact of the plantar plate <NUM>.

In an embodiment, a seal ring <NUM> is configured to improve a connection effect with an upper cover of the plantar plate.

In an embodiment, the plantar plate <NUM> is a metal structure part with a void or a groove. The first force sensor <NUM>, the distance sensor <NUM>, and the posture sensor <NUM> are connected to the shank connector <NUM> via connection wires passing through the void or the groove of the metal structure part. A contact surface of the plantar plate <NUM> with the ground may be a circular plane. When the control unit <NUM> is arranged in the upper body <NUM> of the robot, the connection wires may be connected to the control unit <NUM> in the upper body <NUM> of the robot through the shank connector <NUM>.

In an embodiment, a bottom and an outer side of the metal structure part are cladded with plantar rubber <NUM>. That is, when the plantar plate <NUM> is implemented as the metal structure part, the bottom and the outer side of the plantar plate <NUM> are cladded with the plantar rubber <NUM>.

In an embodiment, the first force sensor <NUM> is an ionic thin-film force sensor. The ionic thin-film force sensor is arranged between the plantar rubber <NUM> and the bottom of the metal structure part. The ionic thin-film force sensor is of a ring shape.

In an embodiment, the distance sensor <NUM> is a thin-film distance sensor. The thin-film distance sensor is centrally arranged between the plantar rubber <NUM> and the bottom of the metal structure part. A thickness of a portion of the plantar rubber <NUM> under the thin-film distance sensor is smaller than a thickness of the plantar rubber <NUM> at another portion.

In an embodiment, a shock absorbing gasket is installed between the posture sensor <NUM> and the metal structure part (the plantar plate <NUM>). The joint assembly <NUM> includes a joint ball socket <NUM>, a ball joint <NUM>, an elastic assembly <NUM>, a lower snap ring <NUM>, a flexible cover <NUM>, and an upper snap ring <NUM>. In response to a reaction force applied to the plantar plate <NUM>, the plantar plate <NUM> drives the joint ball socket <NUM> to rotate relative to the ball joint <NUM> with three degrees of freedom, so that the plantar plate <NUM> adapts to fit the contact surface.

In an embodiment, the elastic assembly <NUM> includes a conical return spring. The conical return spring is configured to be in a passively compressed state in a case that the plantar plate <NUM> is in contact with an obstacle, and release stored energy (elastic potential energy) in a case that the plantar plate is separated from the obstacle, so as to drive the plantar plate <NUM> to restore to an initial state.

In an embodiment, the joint ball socket <NUM> includes a limiting structure. The joint ball socket with the limiting structure are provided with low front and rear edges and high left and right edges. The joint assembly <NUM> may enable the plantar assembly <NUM> to have a certain degree of freedom, so that the plantar assembly <NUM> may rotate by a certain degree. For example, <FIG> is a schematic cross-sectional structural diagram of the joint assembly <NUM> in an embodiment of this application. As shown in <FIG>, the joint assembly <NUM> may include: a joint ball socket <NUM>, a ball joint <NUM>, an elastic assembly <NUM>, an upper snap ring <NUM>, a flexible cover <NUM>, a lower snap ring <NUM>, an upper cover <NUM> of a plantar plate, a ball socket involute groove <NUM>, and a seal ring groove <NUM>.

In an embodiment, the plantar assembly <NUM> and the joint assembly <NUM> are connected with each other by tightly fitting the seal ring groove <NUM> on the upper cover <NUM> of the plantar plate and the seal ring <NUM> in the plantar assembly <NUM> shown in <FIG>.

In an embodiment, the joint ball socket <NUM> may rotate relative to the ball joint <NUM> with three degrees of freedom.

In an embodiment, the joint ball socket <NUM> includes a limiting structure. The joint ball socket with the limiting structure are provided with low front and rear edges and high left and right edges. For a degree of freedom in pitch, the joint assembly <NUM> expands a motion range through the low front and rear edges of the joint ball socket, and for a degree of freedom in roll, the joint assembly <NUM> maintains a small motion range through the high left and right edges of the joint ball socket. The low edges of the joint ball socket <NUM> may form the ball socket involute groove <NUM>. When the ball socket involute groove <NUM> is enlarged, the degree of freedom in pitch of the ball joint <NUM> may be improved. A ball head of the ball joint <NUM> is adapted to a size of the joint ball socket <NUM>, to ensure connection strength between the joint ball socket <NUM> and the ball head of the ball joint <NUM>, thereby preventing disconnection.

In an embodiment, the plantar plate <NUM> is configured to drive, in response to a reaction force from a contact surface, the joint ball socket <NUM> to rotate relative to the ball joint <NUM> with three degrees of freedom, so that the plantar plate <NUM> is adapted to fit the contact surface. When the plantar plate <NUM> is in contact with an obstacle, the reaction force applied to the plantar plate <NUM> by the obstacle drives the joint ball socket <NUM> to adaptively adjust angles of directions of the three degrees of freedom, so as to adjust posture angles of the connected plantar plate <NUM> in the directions of the three degrees of freedom, thereby adaptively adjusting a spatial orientation of the plantar plate <NUM>. When the plantar plate <NUM> is in contact with the obstacle, in order to adaptively adapt the plantar plate <NUM> to fit the obstacle under different contact angles, the angles in the directions of the three degrees of freedom of the joint ball socket <NUM> may be adjusted relative to the ball joint <NUM>.

In an embodiment, an encoder is arranged on the ball joint <NUM>, and a rotation angle of the ball joint <NUM> may be directly measured through the encoder, so as to obtain the posture angles of the connected plantar plate <NUM>.

In an embodiment, when the plantar plate <NUM> is separated from the obstacle, in order to enable the plantar plate <NUM> to restore to an initial spatial orientation state, the elastic assembly <NUM> is arranged in the joint assembly <NUM>. The elastic assembly <NUM> may be a conical return spring. One end of the conical return spring is connected to the plantar plate <NUM>, and another end is connected to the shank connector <NUM>.

In an embodiment, the elastic assembly <NUM> includes a conical return spring. The conical return spring is configured to be in a passively compressed state in a case that the plantar plate <NUM> is in contact with the obstacle, and release stored energy in a case that the plantar plate <NUM> is separated from the obstacle, to drive the plantar plate <NUM> to restore to an initial state. The conical return spring is configured to be in the passively compressed state in a case that the plantar plate <NUM> is in contact with the obstacle. The conical return spring is further configured to release the stored energy (elastic potential energy) in a case that the plantar plate <NUM> is separated from the obstacle, to drive the plantar plate <NUM> to restore to the initial state. When the ball joint <NUM> arbitrarily rotates in the three degrees of freedom, the conical return spring is in the passively compressed state. When the plantar plate is separated from the obstacle, the conical return spring releases the stored energy and drives the plantar plate <NUM> to restore to the initial state. For example, when the plantar plate <NUM> is separated from the obstacle, the ball joint <NUM> restores the angle of the directions of the three degrees of freedom to an initial angle through the conical return spring, to adjust the posture angles of the connected plantar plate <NUM> in the directions of the three degrees of freedom to initial angles, so as to adjust a spatial orientation of the plantar plate <NUM> to restore to an initial spatial orientation.

In an embodiment, the elastic assembly <NUM> is made of an elastic cladding material. Compared with the elastic cladding material, the conical return spring has more stable and consistent elastic performance, and in turn has higher reliability for the return effect of the plantar plate <NUM>.

In an embodiment, a flexible cover <NUM> is cladded on an outer side of the elastic assembly <NUM>. One end of the flexible cover <NUM> may be sleeved on the upper cover <NUM> of the plantar plate, and another end may be sleeved on the shank connector <NUM>.

In an embodiment, the upper snap ring <NUM> and the lower snap ring <NUM> in the joint assembly <NUM> may be configured to fix two ends of the flexible cover <NUM> respectively on the upper cover <NUM> of the plantar plate and the shank connector <NUM>, so that the joint assembly <NUM> is sealed, thereby achieving purposes of dustproof and waterproof.

In an embodiment, the elastic assembly <NUM> includes a conical return spring. The conical return spring is sleeved on a periphery of the ball joint <NUM>, and a lower end of the conical return spring is connected to the plantar plate <NUM>, and an upper end is connected to the shank connector <NUM>.

For example, <FIG> is a schematic cross-sectional structural diagram of the connection assembly <NUM> in an embodiment of this application. As shown in <FIG>, the connection assembly <NUM> may connect a shank portion of an upper body <NUM> of the robot with a joint assembly <NUM>. The connection assembly <NUM> may include: a second force sensor <NUM>, a shank connector <NUM>, a lower flange <NUM>, a wiring hole <NUM>, and an upper flange <NUM>.

In an embodiment, the second force sensor <NUM> is a six-axis force sensor. The six-axis force sensor may be configured to measure a resultant force vector of reaction forces applied to the plantar plate <NUM>. A front end of the six-axis force sensor may be connected to a ball head flange of a ball joint <NUM>, and a rear end of the six-axis force sensor may be connected to the lower flange <NUM>, to conduct a force or torque.

In an embodiment, the shank connector <NUM> is a triangular prism connector. Setting the shank connector in the shape of a triangular prism may facilitate connection between the upper flange <NUM> and the lower flange <NUM>.

In an embodiment, the wiring hole <NUM> is arranged in the shank connector. The wiring hole <NUM> may be used as a channel for arranging connection wires, and the connection wires may be used for a first force sensor <NUM>, a distance sensor <NUM>, a posture sensor <NUM>, an encoder, and the second force sensor <NUM> to upload measurement data to a control unit <NUM>.

In an embodiment, a flexible cover <NUM> is connected to the lower flange of the connector assembly by using an upper snap ring, achieving waterproof and dustproof protection for an entire foot of the robot.

In an embodiment, the shank connector <NUM> is a hollow triangular prism connector; and a lower end of the shank connector <NUM> is connected to the second force sensor <NUM> by using a flange.

The leg assembly for a robot provided in this application may be applied to different legged robots such as bipedal humanoid robots, multi-legged robots, or may be applied to ends of various series connection or parallel connection multi-joint robots, to interact with the environment. When the leg assembly is applied to a legged robot platform as a planta, the leg assembly may adapt to a complex terrain and provide, in real time, effective feedback of a contact state for a control algorithm, thereby improving a balance control effect and a passing capability of the robot. When the leg assembly is applied to a robot platform such as a robotic arm as an end executor, the leg assembly may provide rich environmental perception information for the robot, and realize an adaptive and safe contact and interaction between the robot and the environment. <FIG> is a schematic diagram a robot device to which a leg assembly is applied according to an exemplary embodiment of this application. As shown in <FIG>, the legged robot may be a bipedal humanoid robot, and the robot includes an upper body <NUM> of the robot, a control unit <NUM>, and a leg assembly <NUM>. The leg assembly <NUM> is configured to execute a movement instruction, so that the robot moves according to the movement instruction. The movement instructions may be sent by the control unit <NUM> to the leg assembly <NUM>, and the movement instructions may include a walking instruction and a running instruction. Different types of sensors are installed on the leg assembly <NUM> to detect environmental information at the current moment. The leg assembly <NUM> is electrically connected to the control unit <NUM>, to upload the collected environmental information at the current moment to the control unit <NUM>. The control unit <NUM> analyzes the environmental information, and sends the movement instruction to the leg assembly <NUM>, to control movement of the robot at a next moment.

Therefore, by installing a first force sensor, a distance sensor, a posture sensor, and a second force sensor in a leg assembly for a robot, the leg assembly can perform comprehensive detection of a contact environment, and upload detection results of the sensors to a control unit, so that the control unit comprehensively controls the robot based on the detection results of the sensors. With the solutions shown in this application, rather than obtaining a measurement result in a single aspect through detection of a single pressure sensor, more types and quality of perception information about the environment are obtained by the robot, so that the control unit may obtain more comprehensive detection result, and control the robot to move through the leg assembly according to the detection result, which greatly improves a control effect on the leg assembly of the robot, thereby expanding application scenarios of a legged robot.

<FIG> is a flowchart of a method for applying a leg assembly for a robot to perform sensor detection according to an exemplary embodiment of this application. The method for performing sensor detection is executed by the leg assembly. As shown in <FIG>, the method for performing sensor detection may include the following steps <NUM> to <NUM>.

In step <NUM>, a normal reaction force applied to a plantar plate when the plantar plate is in contact with an obstacle is detected by using a first force sensor, to obtain data of the normal reaction force.

In step <NUM>, a distance between the plantar plate and the obstacle is detected in real time by using a distance sensor, to obtain data of the distance in real time.

In step <NUM>, a spatial orientation of the plantar plate is detected by using a posture sensor, to obtain information about the spatial orientation of the plantar plate.

In step <NUM>, a resultant force of reaction forces applied to the plantar plate when the plantae plated is in contact with the obstacle is detected by using a second force sensor, to obtain vector data of the resultant force.

In step <NUM>, the data of the normal reaction force, the data of the distance, the information about the spatial orientation of the plantar plate, and the vector data of the resultant force of the applied reaction forces are uploaded to a control unit.

In an embodiment, the data of the normal reaction force, the data of the distance, the information about the spatial orientation of the plantar plate, and the vector data of the resultant force of the applied reaction forces are detected by corresponding sensors in real time.

In an embodiment, step <NUM>, step <NUM>, step <NUM>, and step <NUM> may be performed simultaneously, or may not be performed simultaneously. In addition, the control unit may analyze at least two of the data of the normal reaction force, the data of the distance, the information about the spatial orientation of the plantar plate, and the vector data of the resultant force of the applied reaction forces, to perceive the current environment.

Therefore, by installing a first force sensor, a distance sensor, a posture sensor, and a second force sensor in a leg assembly for a robot, the leg assembly can perform comprehensive detection of a contact environment, and upload detection results of the sensors to a control unit, so that the control unit comprehensively controls the robot based on the detection results of the sensors. With the solutions shown in this application, rather than obtaining a measurement result in a single aspect through detection of a single pressure sensor, more types and quality of perception information in the environment are obtained by the robot, so that the control unit may obtain a more comprehensive detection result, and control the robot to move through the leg assembly according to the detection result, which greatly improves a control effect on the leg assembly of the robot, thereby expanding application scenarios of a legged robot.

After considering this specification and practicing the present disclosure, a person skilled in the art may easily conceive of other embodiments of this application. This application is intended to cover any variations, uses or adaptive changes of this application. Such variations, uses or adaptive changes follow the general principles of this application, and include well-known knowledge and conventional technical means in the art that are not disclosed in this application.

Claim 1:
Aleg assembly (<NUM>) for a robot, the leg assembly (<NUM>) comprising:
a connection assembly (<NUM>), configured to connect the leg assembly (<NUM>) with an upper body (<NUM>) of the robot; and
a plantar assembly (<NUM>) comprising a plantar plate (<NUM>), a first force sensor (<NUM>), a distance sensor (<NUM>), and a posture sensor (<NUM>),
the connection assembly (<NUM>) comprising a second force sensor (<NUM>) and a shank connector (<NUM>);
the first force sensor (<NUM>), the distance sensor (<NUM>), the posture sensor (<NUM>), and the second force sensor (<NUM>) being electrically connected to a control unit (<NUM>);
the first force sensor (<NUM>) being configured to detect a normal reaction force applied to the plantar plate (<NUM>) when the plantar plate (<NUM>) is in contact with an obstacle;
the distance sensor (<NUM>) being configured to detect a distance between the plantar plate (<NUM>) and the obstacle in real time;
the posture sensor (<NUM>) being configured to detect a spatial orientation of the plantar plate (<NUM>); and
the second force sensor (<NUM>) being configured to detect a resultant force of reaction forces applied to the plantar plate (<NUM>) when the plantar plate (<NUM>) is in contact with the obstacle,
wherein the plantar plate (<NUM>) is a metal structure part with a void or a groove, and the first force sensor (<NUM>), the distance sensor (<NUM>), and the posture sensor (<NUM>) are connected to the control unit (<NUM>) via connection wires passing through the void or the groove of the metal structure part, and
a bottom and an outer side of the metal structure part are cladded with plantar rubber (<NUM>), wherein
the first force sensor (<NUM>) is an ionic thin-film force sensor, and the ionic thin-film force sensor is arranged between the plantar rubber (<NUM>) and the bottom of the metal structure part, and the ionic thin-film force sensor is of a ring shape, or
the distance sensor (<NUM>) is a thin-film distance sensor, and the thin-film distance sensor is centrally arranged between the plantar rubber (<NUM>) and the bottom of the metal structure part, and a thickness of the plantar rubber (<NUM>) at a portion under the thin-film distance sensor is smaller than a thickness of the plantar rubber (<NUM>) at another portion.