An omnidirectional multi-degree-of-freedom robot motion structure for simulating human behavior

Abstract

The application discloses a kind of omnidirectional multi-degree-of-freedom robot motion structures of human behavior action, motion structure includes upper limb trunk support platform, waist connecting mechanism and lower limb connecting plate;Three groups of waist connecting structure are evenly distributed around the symmetry center circle of lower limb connecting plate and are arranged on lower limb connecting plate, and a group of waist connecting structure includes driving motor, driving motor is arranged on lower limb connecting plate, and the two ends of driving shaft are connected with two output shafts perpendicular to driving shaft, output shaft is connected with mounting seat arranged on the bottom of upper limb trunk support platform through fisheye joint shaft, and fisheye joint shaft, output shaft and mounting seat are all movably connected.The motion structure of the application, the structure is reasonably designed, the effective transmission of power is ensured, so that the robot can realize the more complex action of human-like waist;Real-time PID control is carried out on three driving motors based on inverse kinematics model, which can not only realize accurate control of waist pitching and side swing, but also control the waist to twist.

Description

Technical Field

[0001] This invention relates to the field of humanoid robot technology, and specifically to an omnidirectional multi-degree-of-freedom robot motion structure that mimics human-like behavior and movements. Background Technology

[0002] Humanoid robots, as one of the most challenging fields in current robotics technology, involve multiple key technologies in their design and implementation. In recent years, with the rapid development of intelligent manufacturing and robotics technology, research on the waist structure of bionic robots has gradually increased. An effective waist structure not only needs to provide sufficient support to bear the weight of the upper body, but also needs to allow a wide range of motion to achieve complex movements such as walking and turning, similar to humans.

[0003] CN 118682791 A discloses a waist and hip assembly and a humanoid robot. The waist and hip assembly can realize bending movements such as leaning forward, leaning backward, leaning left, and leaning right and rotating, which improves the flexibility of the waist and further improves the compactness of the overall structure of the waist and hip assembly, reducing the space occupied. However, the waist device of the humanoid robot in the prior art can only realize movements such as leaning forward, leaning backward, leaning left, and leaning right and rotating, and cannot perform more complex waist movements, thus making it difficult to achieve waist movements that are more like those of a human.

[0004] Therefore, developing an omnidirectional lumbar motion mechanism capable of achieving more complex lumbar movements is of great practical significance. Summary of the Invention

[0005] Due to the aforementioned deficiencies in existing technologies, this invention provides an omnidirectional waist motion mechanism capable of achieving more complex waist movements. Specifically, it is an omnidirectional multi-degree-of-freedom robot motion structure that mimics human behavior, overcoming the shortcomings of existing robot hip and waist components that cannot achieve relatively complex waist movements.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A humanoid omnidirectional multi-degree-of-freedom robot motion structure includes an upper limb trunk support platform, a waist connection mechanism, and a lower limb connection plate;

[0008] The upper limb trunk support platform and the lower limb connecting plate are connected by a waist connecting mechanism;

[0009] The waist connection mechanism consists of three sets. The three sets of waist connection structures are installed on the lower limb connection plate and are evenly distributed around the symmetrical center circumference of the lower limb connection plate. Each set of waist connection structures includes a drive motor, which is installed on the lower limb connection plate. The drive shaft of the drive motor is horizontally arranged and has two output shafts that are perpendicular to and parallel to each other connected to both ends of the drive shaft. The output shafts are connected to the mounting base installed at the bottom of the upper limb torso support platform through fisheye connector shafts. The fisheye connector shaft, the output shafts, and the mounting base are all movably connected.

[0010] The aforementioned structure aims to connect the torso and legs of the humanoid robot, enhancing its mobility and stability. This invention utilizes the compliant movement characteristics of the human waist, designing three active ball joint mechanisms. This not only accommodates waist pitch, lateral movement, and torsion, but also enables pose control at any position and angle. When the drive motor is in its initial position, the waist maintains a static posture similar to that of a human. This structural design ensures efficient power transmission, enabling the robot to perform more complex waist-like movements and enhancing its adaptability to different environments.

[0011] The fisheye connector on the fisheye joint shaft gives the connection a small range of twisting ability, which can better fit the human waist movement.

[0012] The upper limb and torso support platform is used to connect the upper limbs and torso, enabling the torso to perform more human-like movements when the waist performs complex actions; the lower limb connecting plate is used to connect the leg components.

[0013] When the drive motor is in operation, it will cause the output shaft to rotate around the drive shaft of the drive motor, thereby driving the upper limb and torso support platform to move. The combined movement of the three sets of waist connection structures can enable the torso to pitch, sway, and twist at a certain angle.

[0014] As a preferred technical solution:

[0015] As described above, in an omnidirectional multi-degree-of-freedom robot motion structure that mimics human behavior and actions, both ends of the fisheye joint shaft are provided with fisheye joints.

[0016] The two output shafts have matching pin holes at the ends away from the drive shaft, which are also compatible with the fisheye connector. Rotary pin I is inserted into the pin hole, and the output shaft is movably connected to one end of the fisheye connector shaft through rotating pin I. The other end of the fisheye connector shaft is movably connected to the mounting base through rotating pin II.

[0017] As described above, in an omnidirectional multi-degree-of-freedom robot motion structure that mimics human behavior, the drive motor is mounted on the lower limb connecting plate via a drive motor fixing device.

[0018] As described above, in an omnidirectional multi-degree-of-freedom robot motion structure that mimics human behavior, limiting blocks are provided on both sides of the lower limb connecting plate, and the limiting blocks are perpendicular to the lower limb connecting plate.

[0019] The limiting block is located between the upper limb and torso support platform and the lower limb connecting plate. The limiting block is used to restrict the range of motion of the waist.

[0020] As described above, an omnidirectional multi-degree-of-freedom robot motion structure that mimics human behavior has three sets of waist connection structures located between two limiting blocks.

[0021] As described above, in an omnidirectional multi-degree-of-freedom robot motion structure that mimics human behavior, the drive shafts of the three sets of waist-connecting structures form an equilateral triangle.

[0022] With the center of the lower limb connecting plate as the origin, the center positions of the three drive motors are all 120 degrees away from the line containing the origin. This means the drive shafts of the three motors are evenly distributed on a circle centered on the center of the lower limb connecting plate. The human waist has a large forward and backward movement angle, but a smaller left-right and twisting movement angle. Therefore, the output flange of the motor that primarily drives the waist's pitching motion is perpendicular to the robot's coronal plane, thus achieving a large range of motion. Twisting is mainly achieved by a ball joint mechanism (i.e., a fisheye joint), which can both limit the range of motion and allow for more human-like movements.

[0023] The humanoid robot motion structure with omnidirectional multi-degree-of-freedom behavior described above includes an attitude sensor module and a controller module.

[0024] The posture sensor module is used to collect the posture of the upper limb trunk support platform and the lower limb connecting plate in real time.

[0025] The controller module is used to process the pose signal collected by the attitude sensor module, obtain its current pose, determine the drive motor control scheme according to the desired pose, and send the drive motor control scheme to the drive motor.

[0026] As described above, the omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior includes an attitude sensor module comprising attitude sensors placed at the center of the upper limb trunk support platform and the lower limb connecting plate, respectively, for real-time acquisition of attitude information of the upper limb trunk support platform and the lower limb connecting plate.

[0027] The rotation angle of the drive motor is calculated based on the given desired posture, and a command is sent to the drive motor to control its rotation. The posture of the upper limb and torso support platform is collected in real time by a posture sensor to determine whether the platform is in the desired posture. The motor output is then corrected in real time by a PI controller to achieve stability of the waist movement.

[0028] The PI controller is a positional PID controller. It calculates the desired posture using the PID controller and sends the control quantity to the driver. The PID controller corrects the position based on the error between the actual posture and the desired posture, making the waist movement more stable.

[0029] The three drive motors have different functions, and their coordinated movement controls the waist's pitch, sway, and twisting at a certain angle.

[0030] This invention not only designs a structure that better conforms to human movement from a structural perspective, but also makes the robot's waist movement more human-like from a control strategy perspective. Compared to serial robots, the forward kinematics of the parallel robot built in this invention are more difficult to solve, but the inverse kinematics do not need to be solved through forward kinematics and can be directly obtained through geometric methods. Therefore, in terms of kinematic analysis, the inverse kinematics is solved directly.

[0031] This invention controls the position of an upper limb and torso support platform by controlling three sets of waist connection structures based on inverse kinematics. In the process of deriving inverse kinematics, the relationship between the rotation angle of the motor and the pose of the upper limb and torso support platform relative to the lower limb connection plate is established. When the waist needs to move, the desired pose is given first, and the angle that each drive motor needs to rotate corresponding to the desired pose is solved using inverse kinematics. Then, the desired rotation angle command is sent to the drive motor to control the upper limb and torso support platform to reach the desired pose.

[0032] The above technical solution is only one feasible technical solution of the present invention. The scope of protection of the present invention is not limited thereto. Those skilled in the art can reasonably adjust the specific design according to actual needs.

[0033] The above invention has the following advantages or beneficial effects:

[0034] (1) The omnidirectional multi-degree-of-freedom robot motion structure of the present invention adopts a parallel structure for the waist design, which has high degree of freedom, high effective load-weight ratio, high stiffness and precision, as well as better dynamic performance and easy control.

[0035] (2) The omnidirectional multi-degree-of-freedom robot motion structure of the present invention can accurately simulate different movements of the human waist and has human-like motion ability, flexibility, multi-functionality and operation performance.

[0036] (3) The omnidirectional multi-degree-of-freedom robot motion structure of the present invention with humanoid behavior adopts a control strategy based on inverse kinematics model. Compared with the traditional forward kinematics model, the inverse dynamics model is easier to calculate and has higher control accuracy.

[0037] (4) The omnidirectional multi-degree-of-freedom robot motion structure of the present invention can achieve self-stabilization function within a certain range when the robot's lower limbs move, which is beneficial for performing some fine tasks and has good application prospects. Attached Figure Description

[0038] The invention, its features, shape, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals denote like parts throughout the drawings. The drawings are not drawn to scale; their purpose is to illustrate the gist of the invention.

[0039] Figure 1 This is a front view of the omnidirectional multi-degree-of-freedom robot motion structure of the present invention in a horizontal posture.

[0040] Figure 2 This is a three-dimensional schematic diagram of the omnidirectional multi-degree-of-freedom robot motion structure of the present invention in a horizontal posture.

[0041] Figure 3 This is a three-dimensional schematic diagram of the omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior and actions of the present invention in a pitch posture.

[0042] Figure 4 The left view of the omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior and actions of the present invention in a pitch posture;

[0043] Figure 5 This is a three-dimensional schematic diagram of the omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior and action of the present invention in a side-swinging posture.

[0044] Figure 6 This is a schematic diagram illustrating the structural mathematical description of the omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior and actions according to the present invention.

[0045] Figure 7 This is a schematic diagram of the coordinate system rotating about the z-axis;

[0046] Figure 8 To simplify the configuration of the drive unit Figure 1 ;

[0047] Figure 9 To simplify the configuration of the drive unit Figure 2 ;

[0048] Among them, 1 is the upper limb and torso support platform, 2 is the waist connection mechanism, 3 is the fisheye connector, 4 is the fisheye connector shaft, 5 is the limit block, 6 is the output shaft, 7 is the drive motor, 8 is the lower limb connection plate, and 9 is the drive motor fixing device. Detailed Implementation

[0049] To make the objectives, technical solutions, beneficial effects, and significant advancements of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0050] Obviously, all the embodiments described are only some embodiments of the present invention, and not all embodiments; based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] like Figure 1 As shown, Figure 1 This is a schematic diagram of the overall structure of an omnidirectional multi-degree-of-freedom robot motion structure that mimics human-like behavior and actions. Figure 2 Other perspective diagrams illustrating the initial state of the invention. Figure 3 , 4 This is a schematic diagram of the structure in a pitching position. Figure 5 This is a schematic diagram of the structure in a sideways state.

[0052] The omnidirectional multi-degree-of-freedom robot motion structure that mimics human behavior and movements includes an upper limb trunk support platform 1, a waist connection mechanism 2, and a lower limb connection plate 3;

[0053] The upper limb and torso support platform 1 and the lower limb connecting plate 3 are connected by a waist connecting mechanism 2;

[0054] There are three sets of waist connection mechanism 2 (i.e., equivalent length variable actuator). The three sets of waist connection structure 2 are installed on the lower limb connection plate 3 and are evenly distributed around the symmetrical center circle of the lower limb connection plate 3 (the straight lines where the drive shafts of the drive motors 7 of the three sets of waist connection structure 2 are located form an equilateral triangle). One set of waist connection structure 2 includes a drive motor 7. The drive motor 7 is installed on the lower limb connection plate 3 through a drive motor fixing device 9. The drive shaft of the drive motor 7 is arranged horizontally and two output shafts 6 that are perpendicular to and parallel to each other are connected to both ends of the drive shaft. The output shafts 6 are connected to the mounting base installed at the bottom of the upper limb torso support platform 1 through a fisheye connector shaft 4. The fisheye connector shaft 4, the output shafts 6, and the mounting base are all movably connected.

[0055] Specifically, both ends of the fisheye connector shaft 6 are provided with fisheye connectors 3. The two output shafts 6 have matching pin holes that are matched with the fisheye connectors 3 at the ends away from the drive shaft. Rotating pins I are inserted into the pin holes, and the output shafts 6 are movably connected to one end of the fisheye connector shaft 6 through rotating pins I. The other end of the fisheye connector shaft 6 is movably connected to the mounting base through rotating pins II.

[0056] Both sides of the lower limb connecting plate 3 are provided with limiting blocks 5, and the limiting blocks 5 are perpendicular to the lower limb connecting plate 3;

[0057] The limiting block 5 is located between the upper limb trunk support platform 1 and the lower limb connecting plate 3, and the three sets of waist connecting structures 2 are located between the two limiting blocks 5.

[0058] The structural mathematical modeling diagram of the humanoid robot using an omnidirectional, multi-degree-of-freedom waist motion structure is shown below. Figure 6 As shown.

[0059] The base coordinate system has three orthogonal axes x, y, and z, while the platform coordinate system has x′, y′, and z′. The upper limb and torso support platform has three degrees of freedom relative to the lower limb connecting plate: vertical motion along the Z-axis of the lower limb connecting plate and rotational motion around the x-axis and y-axis of the platform. The transformation of the upper limb and torso support platform relative to the lower limb connecting plate includes translation and rotation variables. To describe the rotation variable, ZYX Euler angles are used to describe the rotation of the upper limb and torso support platform relative to the lower limb connecting plate. The ZYX Euler angles are defined as follows: rotation angle Ψ (yaw) around the z-axis; rotation angle θ (pitch) around the y-axis; and rotation angle φ (roll) around the x-axis. If we first consider the rotation of the coordinate axes around the z-axis, as... Figure 7 As shown.

[0060] Given that the two coordinate systems only undergo rotation Ψ relative to the z-axis, the following mathematical derivation can be obtained:

[0061] (1)

[0062] (2)

[0063] (3)

[0064] Therefore, by combining equations (1), (2), and (3), the rotation matrix R can be defined. z (Ψ)

[0065] (4)

[0066] in (5)

[0067] Similarly, we can derive the rotation matrix R about the y-axis. y (θ) and the rotation matrix R about the x-axis x The corresponding form of (φ) is shown in equations (6) and (7):

[0068] (6)

[0069] (7)

[0070] The complete rotation matrix of the upper limb trunk support platform relative to the lower limb connecting plate, following the rotation order of the ZYX axes, can be seen in equation (8).

[0071] (8)

[0072] The above describes the process of deriving the complete rotation matrix from the lower limb connecting plate to the upper limb trunk support platform. For the i-th leg, P is defined as follows: i B is the anchor point of the actuator on the upper limb torso support platform. i P is the anchor point of the actuator on the lower limb connecting plate. i The vector q relative to the origin of the lower limb connecting plate coordinate system i It can be derived from equation (9):

[0073] (9)

[0074] Where T is the translation vector from the lower limb connecting plate to the upper limb trunk support platform, and a known vector b is defined. i Let B be the distance from the origin of the lower limb connecting plate to the center of the i-th actuator axis. i The distance, now q i and b i All of these are calculable or known, therefore the corresponding point P from the midpoint of the actuator axis to the upper limb trunk support platform can be calculated using equation (10). i The vector l of the i-th leg i :

[0075] (10)

[0076] The ultimate goal of solving the kinematics is to achieve the given platform posture. The rotation angle corresponding to each motor can be obtained through inverse kinematics. Generally, the method for solving inverse kinematics is to first calculate the forward kinematics and then solve the inverse kinematics through the forward kinematics. This method is more practical for serial robots such as robotic arms, but not for parallel robots. The waist structure of this invention belongs to a parallel robot, and it is difficult to solve the forward kinematics. However, the inverse kinematics does not need to be solved through the forward kinematics and can be directly obtained through geometric methods. Therefore, in terms of kinematic analysis, the inverse kinematics is solved directly.

[0077] Next, we use a geometric method to solve the inverse kinematics of the i-th leg. The simplified configuration diagram of the i-th leg is as follows: Figures 8-9 As shown.

[0078] This invention is similar to the model described above. Figure 6 The slight difference lies in the choice of the origin coordinate system. Figure 6The origin coordinate system is chosen to be located at the center of the lower limb connecting plate. This project takes the height of the motor's output shaft into account, so it's assumed that the origin coordinate system of the lower limb connecting plate is chosen slightly above the center of the lower limb connecting plate, with its height exactly aligned with the height of the motor's output shaft. This simplifies subsequent calculations. Figure 8 The image shows the initial state, as shown below. Figure 9 The figure shows the motor rotation angle α. i The state afterward.

[0079] For inverse kinematics solutions, the known condition is the expected pose of the waist, which includes a translation vector T and a rotation vector. The upper limb trunk support platform has three degrees of freedom relative to the lower limb connecting plate: vertical movement along the z-axis and rotational movement around the x-axis and y-axis of the platform. When the platform is in the initial position, z=0, the upward movement is the positive direction, the rotation angle around the x-axis is φ, and the rotation angle around the y-axis is θ. Then, the rotation matrix (9) from the lower limb connecting plate to the upper limb trunk support platform can be obtained from the three known quantities using equation (8).

[0080] (11)

[0081] for Figure 8 and 9 p i and b i Since all quantities are known, q can be calculated using equation (9). i Then, l is calculated using equation (10). i Thus, triangle OP... i B i The lengths of the three sides are known, which is the vector q. i b i l i The modulus can be used to calculate angle β using the law of cosines. i The calculation method is shown in equation (12):

[0082] (12)

[0083] The lengths h1 and h2 of the two connecting rods are also known quantities, and the angle Φ can be calculated using the law of cosines. i The calculation method is shown in equation (13):

[0084] (13)

[0085] Finally, the required rotation angle of the motor can be calculated using equation (14):

[0086] (14)

[0087] The omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior of the present invention is controlled based on the above content. The omnidirectional multi-degree-of-freedom waist motion structure for humanoid robots includes an attitude sensor module and a controller module. The attitude sensor module is used to collect the pose of the upper limb torso support platform and the lower limb connecting plate in real time. Specifically, it includes attitude sensors placed at the center positions of the upper limb torso support platform and the lower limb connecting plate, respectively, for collecting the attitude information of the upper limb torso support platform and the lower limb connecting plate in real time. The controller module is used to process the pose signals collected by the attitude sensor module, obtain its current pose, determine the drive motor control scheme according to the desired pose, and send the drive motor control scheme to the drive motor.

[0088] Specifically, inverse kinematics is used to calculate the required rotation angle for each motor corresponding to the desired posture. Given the desired posture, the required rotation angle for the drive motor is calculated, and a command is sent to the drive motor. A position-based PID controller is used to calculate the control quantity for the desired posture and send it to the driver. By reading the error between the actual posture from the posture sensor and the desired posture, PID correction is performed to make the waist movement more stable.

[0089] Those skilled in the art should understand that variations can be implemented by combining existing technology with the above embodiments, which will not be elaborated here. Such variations do not affect the essence of the present invention, and will not be elaborated here either.

[0090] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a conventional manner in the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention's technical solutions still fall within the protection scope of the present invention.

Claims

1. A human-like omnidirectional multi-degree-of-freedom robot motion structure, characterized in that: It includes an upper limb and trunk support platform, a lumbar connection mechanism, and a lower limb connection plate; The upper limb trunk support platform and the lower limb connecting plate are connected by a waist connecting mechanism; The waist connection mechanism consists of three sets. The three sets of waist connection structures are installed on the lower limb connection plate and are evenly distributed around the symmetrical center circumference of the lower limb connection plate. One set of waist connection structures includes a drive motor, which is installed on the lower limb connection plate. The drive shaft of the drive motor is horizontally arranged and has two output shafts that are perpendicular to and parallel to each other connected to both ends of the drive shaft. The output shafts are connected to the mounting base installed at the bottom of the upper limb torso support platform through fisheye connector shafts. The fisheye connector shaft, the output shafts, and the mounting base are all movably connected. Both sides of the lower limb connecting plate are provided with limiting blocks, and the limiting blocks are perpendicular to the lower limb connecting plate; The limiting block is located between the upper limb trunk support platform and the lower limb connecting plate; Three sets of waist connection structures are located between the two limiting blocks; The omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior is applied to the connection between the torso and legs of the humanoid robot.

2. The omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior and actions according to claim 1, characterized in that, Both ends of the fisheye connector shaft are provided with fisheye connectors; The two output shafts have matching pin holes at the ends away from the drive shaft, which are also compatible with the fisheye connector. Rotary pin I is inserted into the pin hole, and the output shaft is movably connected to one end of the fisheye connector shaft through rotating pin I. The other end of the fisheye connector shaft is movably connected to the mounting base through rotating pin II.

3. The omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior and actions according to claim 1, characterized in that, The drive motor is mounted on the lower limb connecting plate via a drive motor fixing device.

4. The omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior and actions according to claim 1, characterized in that, The drive shafts of the three sets of waist-connecting structures form an equilateral triangle.

5. The omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior and actions according to claim 1, characterized in that, The omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior includes an attitude sensor module and a controller module. The posture sensor module is used to collect the posture of the upper limb trunk support platform and the lower limb connecting plate in real time. The controller module is used to process the pose signal collected by the attitude sensor module, obtain its current pose, determine the drive motor control scheme according to the desired pose, and send the drive motor control scheme to the drive motor.

6. The omnidirectional multi-degree-of-freedom robot motion structure for humanoid behavior and actions according to claim 5, characterized in that, The posture sensor module includes posture sensors placed at the center of the upper limb trunk support platform and the lower limb connecting plate, respectively, for real-time acquisition of posture information of the upper limb trunk support platform and the lower limb connecting plate.

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