Teleoperation Method for Lunar Exploration Mobile Robotic Arm Based on Single Master-End Adaptive Switching

Abstract

This invention provides a teleoperation method for a lunar exploration mobile robotic arm based on single-master adaptive switching, comprising: constructing a seven-DOF redundant robotic arm system with master and slave ends and corresponding kinematic models; establishing hybrid asymmetric mapping models for the mobile platform and the robotic arm respectively, and designing adaptive switching factors to achieve adaptive switching between the mobile platform and the robotic arm, and between the robotic arm itself, under dual mapping modes; and integrating the switching factors to establish a force feedback model, using the artificial potential field method to design virtual repulsive forces during lunar rover movement and virtual guiding forces during robotic arm manipulation, while incorporating real end-effector measurement data. This invention provides operators with a more relaxed and convenient single-master teleoperation method integrating slave-end mobile platform and robotic arm manipulation, improving the efficiency and safety of teleoperation and the operator's environmental awareness, reducing the operator's workload, and lowering the operator's decision-making pressure.

Description

Technical Field

[0001] This invention belongs to the field of teleoperated robot technology, specifically relating to a teleoperation method for a lunar exploration mobile robotic arm based on single master-end adaptive switching. Background Technology

[0002] With the continuous advancement of lunar exploration technology, the tasks of collecting lunar soil samples and the collaborative handling and assembly required for future lunar research stations place higher demands on lunar exploration robots. Mobile robotic arms, with their high precision, strong stability, and flexible operation capabilities, can perform complex lunar soil drilling and sampling tasks. Furthermore, during the construction of lunar research stations, mobile robotic arms can assist researchers in deploying experimental equipment and constructing research facilities, greatly improving construction efficiency and safety.

[0003] While robots have rapidly developed autonomous capabilities, their limitations remain prominent in unstructured and complex environments, making it difficult for them to fully replace humans in performing dangerous or inaccessible tasks in the foreseeable future. Human-robot interaction-based master-slave teleoperated robot systems remain a necessary approach to solving this problem. Among master-slave teleoperated robot systems, heterogeneous master-slave systems have attracted attention due to their flexibility and adaptability. Compared to isomorphic master-slave systems, heterogeneous master-slave systems allow for differences in mechanical structure, size, and number of joints between the master and slave robots, greatly enriching equipment choices and enhancing the system's practicality and application range. However, this heterogeneity also introduces complexity in motion mapping, particularly in highly redundant applications such as mobile robotic arms. The master-slave heterogeneity problem requires operators to exert more effort to coordinate the movements between the master and slave robots, increasing workload and potentially affecting operational effectiveness. Therefore, reducing the operator's workload has become a top priority in the research of heterogeneous master-slave systems. Summary of the Invention

[0004] Objective: The technical problem this invention aims to solve is to address the shortcomings of existing technologies by providing a teleoperation method for a lunar exploration mobile robotic arm based on single-master adaptive switching. The method includes a hybrid asymmetric mapping model of position and velocity for the six-wheeled lunar rover platform and a hybrid asymmetric mapping model of position-velocity and position-position for the robotic arm. It also considers a force feedback strategy for adaptive switching between the slave platform and the robotic arm, providing operators with a more relaxed and convenient single-master teleoperation method that integrates the manipulation of the slave platform and the robotic arm, reducing the operator's workload and decision-making pressure.

[0005] The specific implementation scheme of this invention includes the following steps:

[0006] Step 1: Establish the kinematic model of the master-slave robot. The master robot is specifically a master six-DOF robot, and the slave robot is specifically a slave lunar exploration mobile robotic arm. The slave lunar exploration mobile robotic arm includes a slave lunar rover and a slave seven-DOF redundant robotic arm.

[0007] Step 2: Establish an asymmetric mapping model of position and velocity for the lunar rover at the slave end, and establish a hybrid asymmetric mapping model including position and velocity and position and position mapping for the seven-DOF redundant manipulator at the slave end. Design adaptive switching coefficients to realize the autonomous switching of the movement state, operation state and manipulator dual mapping mode of the seven-DOF redundant manipulator at the slave end.

[0008] Step 3: Establish the force feedback model of the master-end six-DOF robot. The force feedback received by the master-end six-DOF robot includes the virtual repulsive force feedback of the slave-end lunar exploration mobile robotic arm in the moving state and the virtual guiding force or real contact force feedback in the operating state.

[0009] In step 1, the kinematic model of the master-end six-DOF robot is specifically as follows:

[0010]

[0011] (1)

[0012] Among them, the end effector position of the six-DOF robot at the master end. This represents the calibration position of the master-end six-DOF robot, where T represents the matrix transpose. , , These represent the position vectors from the origin to the end effector in the six-DOF robot coordinate system. Projection on axis Projection on axis and Projection on the axis; , , These are the first joint angle, second joint angle, and third joint angle of the master-end six-DOF robot; The sum of the second and third joint angles of the master-end six-DOF robot, i.e. ; and These are the position vectors from the origin to the end effector in the master-end six-DOF robot coordinate system. Projection on a plane and Projection on the axis; and These are the lengths of the first link and the second link of the main-end six-DOF robot, respectively.

[0013] The master-end six-DOF robot includes a six-DOF manipulator. All mapping modes use the end-effector position in Cartesian coordinates as input, specifically the geometric center of the fourth joint of the manipulator. Therefore, the kinematic modeling of the master-end six-DOF robot only utilizes the angles of the first three joints. , , ;

[0014] The master computer mounted on the master six-DOF robot collects the angles of the first three joints of the robot. , , The end effector position of the six-DOF robot at the master end is calculated according to formula (1). ;

[0015] In step 1, the kinematic model of the lunar rover specifically includes:

[0016] Based on Ackermann steering geometry, the forward speed of the lunar rover from the end... and rotational angular velocity The kinematic relationship between the ten joints of the lunar rover and the rover itself is as follows:

[0017]

[0018] (2)

[0019] The lunar rover's ten joints include the steering joints of the four front and rear wheels and the drive joints of all six wheels. , , , These are the steering angles of the left front wheel, right front wheel, left rear wheel, and right rear wheel of the lunar rover. , , , , , These are the angular velocities of the left front wheel, right front wheel, left middle wheel, right middle wheel, left rear wheel, and right rear wheel of the lunar rover. This refers to the half-wheelbase. It is half the wheel track; The radius of the wheel;

[0020] Using formula (2), the slave computer on the lunar exploration mobile robotic arm will receive the forward speed from the master computer. and rotational angular velocity The calculation is used to generate control commands for the ten joints of the mobile platform and then send them to the drive unit of the lunar rover.

[0021] In step 1, the kinematic model of the seven-DOF redundant manipulator is as follows:

[0022]

[0023]

[0024]

[0025] Among them, from the end position of the seven-degree-of-freedom redundant robotic arm To determine the calibration position of the end effector of the seven-DOF redundant robotic arm, where , , These represent the position vectors from the origin to the end effector in the six-DOF robot coordinate system. Projection on axis Projection on axis and Projection on the axis; joint rotation angle of the seven-DOF redundant robotic arm. Let be the joint rotation vector of the seven-DOF redundant robotic arm, where , , , , , , These represent the rotation angles of the first, second, third, fourth, fifth, sixth, and seventh joints of the seven-DOF redundant robotic arm from the slave end, respectively; and the nonlinear vector mapping function of the seven-DOF redundant robotic arm from the slave end. This establishes the mapping relationship between joint rotation vectors and end-effector positions based on the DH method; from the Jacobian of the seven-DOF redundant manipulator. The velocity Jacobian matrix is ​​established based on the vector product method. for Moore–Penrose generalized inverse matrix; It is a constant positive definite gain matrix; the end-effector velocity of the seven-DOF redundant robotic arm. In the robotic arm position and velocity mapping mode, the position is directly obtained after solving the mapping mode. In the robotic arm position and position mapping mode, it needs to be obtained through time differentiation. The desired position of the end effector of the seven-degree-of-freedom redundant robotic arm is obtained from the position. In the robotic arm position and velocity mapping mode, it needs to be obtained through time integration; in the robotic arm position and position mapping mode, it can be directly obtained after solving the mapping mode; from the angular velocity of the seven-degree-of-freedom redundant robotic arm joints. This represents the vector composed of the angular velocities of each joint of the seven-DOF redundant robotic arm from the end, representing the joint rotation angle of the seven-DOF redundant robotic arm from the end. The differential.

[0026] In step 2, a mapping relationship between joint rotation vectors and end effector positions is established based on the DH method. The asymmetric mapping model includes a mapping mode between the lunar rover's position and velocity, and the hybrid asymmetric mapping model includes a mapping mode between the robotic arm's position and velocity and a mapping mode between positions. Specifically, it includes:

[0027] The position and velocity mapping pattern of the lunar rover from the end is represented as follows:

[0028]

[0029]

[0030] Among them, the main end movement distance The current position of the master six-DOF robot is relative to its initial zero position. Distance on the plane; rotation angle of the main end The current position and initial zero position of the master six-DOF robot The angle of rotation of the axis; Let the velocity vector of the lunar rover be the velocity vector from the end of the rover. ; For the adaptive switching factor of the lunar rover from the slave end; for the scaling factor of the lunar rover from the slave end. ,in , These are constants relating to velocity and angular velocity, respectively. , The six-DOF robot at the master end is in Current and initial positions in the direction. , They are respectively Current and initial positions in the direction; It is a function that expands a vector into a diagonal matrix;

[0031] The six-DOF robot coordinate system of the master end has its origin at the geometric center of the first joint, and the axis of rotation of the first joint is... The axis, with vertically upward as the positive direction, is the axis of rotation of the second joint when the first joint is in the zero position. The axis is determined according to the right-hand screw rule. axis;

[0032] The vehicle coordinate system is defined with the geometric center of the lunar rover as its origin and the direction of travel as... The axis is established perpendicular to the upper surface of the lunar rover from the end. The axis, with the vertically upward direction as positive, is determined according to the right-hand screw rule. axis;

[0033] The position and speed mapping mode of the robotic arm is represented as follows:

[0034]

[0035] in, , , , These are the coordinate systems of the seven-DOF redundant robotic arm at the end of the robotic arm and the slave end, respectively. , , Velocity component along the axial direction; Adaptive switching factor for the seven-DOF redundant robotic arm at the end; scaling factor for the seven-DOF redundant robotic arm at the end. ,in , , They are respectively about , , A constant velocity in the direction; end-effector position of a six-DOF robot. ,in , , The positions of the robotic arm's end effector in the seven-DOF redundant robotic arm coordinate system are respectively: , , Projection along the axial direction;

[0036] The coordinate system of the seven-degree-of-freedom redundant robotic arm has its origin at the geometric center of the plane connecting the robotic arm and the vehicle body, and the axis of rotation of the first joint of the robotic arm is... axis, and The axes are in the same direction, determined by the right-hand screw rule. axis;

[0037] The position of the robotic arm and the position mapping mode are represented as follows:

[0038]

[0039]

[0040] in, , , , These are the coordinate systems of the seven-DOF redundant robotic arm at the end of the robotic arm and the slave end, respectively. , , Position component along the axis; It is a constant proportionality factor. , , , They are respectively , , Gain factors in the three axial directions; The initial position of the end effector of the seven-DOF redundant manipulator when switching from the position and position mapping mode; This represents the initial position of the master end effector of the six-DOF robot when switching from the seven-DOF redundant manipulator to the position and position mapping mode. The position of the robotic arm's end effector changes after switching from mapping mode to position and position mapping mode;

[0041] In the robotic arm position and speed mapping mode, the slave computer will receive the desired speed of the end effector from the master computer. And the expected position of the end effector obtained through integration. Analytical calculation is performed as a joint angular velocity vector. The data is then sent to the actuators of each joint of the robotic arm; in the position and position mapping mode of the robotic arm, the slave computer will receive the desired position of the end effector from the master computer. And the expected speed of the end effector obtained through differentiation. Analytical calculation is performed as a joint angular velocity vector. It then sends the commands to the actuators of each joint of the robotic arm, thereby enabling the tracking of the desired position at the end effector.

[0042] The distance from the end effector of the seven-degree-of-freedom redundant robotic arm to the target object When the distance exceeds a certain value, a position and velocity mapping mode is used to enable the robotic arm's end effector to quickly approach the target; when the distance... As the size decreases gradually, a position-to-position mapping mode is used to ensure the accuracy of task execution.

[0043] In step 2, the hybrid asymmetric mapping model, combined with the switching control strategy, is designed with the following weighted mapping of the hybrid mapping mode:

[0044]

[0045] in, For complex variables, For switching factors, , Indicates about and nonlinear functions, The distance between the seven-DOF redundant robotic arm and the target; when When the size decreases to 2cm to 5cm As the value gradually decreases from 1 to 0, the robotic arm switches from position and speed mapping mode to position and position mapping mode.

[0046] In step 2, the motion state of the seven-DOF redundant robotic arm at the slave end is switched using an adaptive switching coefficient. Specifically, this involves controlling the switching process between the movement state of the lunar rover and the operation state of the robotic arm through an adaptive switching factor. This includes:

[0047] Define the time-varying interval of the adaptive switching factor as the switching state, and denote the distance between the rover and the target when entering the switching state as... When leaving the switching state, the distances between the lunar rover and the target are respectively When the distance between the lunar rover and the target is... Greater than At this time, the adaptive switching factor of the seven-degree-of-freedom redundant robotic arm is... Weighting factors for the forward motion state of the lunar rover Weighting factor for the turning motion state of the lunar rover The seven-DOF redundant robotic arm is in a moving state; when the distance between the lunar rover and the target is... Less than And greater than hour, Gradually increase to 1, and , Gradually decreasing to 0, the seven-DOF redundant robotic arm gradually switches from the movement state of the slave lunar rover to the manipulation state of the robotic arm; as the distance between the slave lunar rover and the target... Less than At this time , , The seven-degree-of-freedom redundant robotic arm is in a manipulator state.

[0048] The forward motion state weighting factor of the slave lunar rover Steering motion state weighting factor And the adaptive switching factor from the seven-degree-of-freedom redundant robotic arm. Specifically:

[0049]

[0050] in, Indicates about , nonlinear functions, Indicates about , nonlinear functions, Indicates about Nonlinear functions.

[0051] Inspired by the artificial potential field method and incorporating real-world measurements from the end effector's sensors, a force feedback model for a six-DOF robot at the master end is established. Based on the distance between the slave mobile platform or robotic arm and obstacles or targets in the environment, the virtual guidance force feedback of the slave mobile platform during movement is determined. And virtual guidance force feedback for the robotic arm When the robotic arm contacts the target, the force feedback of the robotic arm is entirely provided by the force sensor measurements.

[0052] In step 3, the force feedback model of the master-end six-DOF robot is as follows:

[0053]

[0054] in, Main feedback force; This is to provide virtual repulsive force feedback from the lunar rover while it is in motion; Force feedback from a redundant robotic arm with seven degrees of freedom.

[0055] In step 3, the virtual repulsive force feedback of the slave lunar rover in its moving state Specifically:

[0056]

[0057] in, Let e ​​be the distance vector from the obstacle to the rover at the other end, and let e be the natural constant. , It is a positive real number.

[0058] Force feedback from the seven-degree-of-freedom redundant robotic arm Specifically:

[0059]

[0060]

[0061] in, Piecewise function The right intersection point of the first two segments of the function; The distance vector from the target object to the end effector; The measured values ​​are from the force sensor mounted on the end effector. , , It is a positive real number.

[0062] The present invention also provides an electronic device, including a processor and a memory, the memory storing program code that, when executed by the processor, causes the processor to perform the steps of the method.

[0063] The beneficial effects of the present invention are as follows: 1. The asymmetric mapping model of position and velocity of the six-wheeled mobile platform of the lunar rover and the hybrid asymmetric mapping model of position-velocity and position-position of the robotic arm designed in this invention utilize the advantages of the slave-end mobile robotic arm to map the limited workspace of the master end to the infinite workspace of the slave end, and realize the automatic switching of multiple mapping modes.

[0064] 2. Compared with the traditional master-slave heterogeneous teleoperated robot position and speed switching mode, the weighted mapping of the hybrid mapping mode of the robotic arm designed in this invention does not require manual switching, and the motion continuity can be guaranteed.

[0065] 3. The force feedback model based on single master-end adaptive switching designed in this invention has good adaptability to complex and unstructured environments, can improve the operator's perception of the environment, and provide guidance to the operator.

[0066] In summary, this invention applies a single master-end adaptive switching method to the remote operation of a lunar exploration mobile robotic arm, providing operators with a more relaxed and convenient single master-end remote operation mode that integrates the slave-end mobile platform and robotic arm manipulation. This improves the efficiency and safety of remote operation, enhances the operator's environmental awareness, reduces the operator's workload, and lowers the operator's decision-making pressure. Attached Figure Description

[0067] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0068] Figure 1 This is a connection diagram of the master-slave heterogeneous teleoperated robot of the present invention.

[0069] Figure 2 This is a schematic diagram of the Ackerman steering geometry for a mobile platform.

[0070] Figure 3 This is a schematic diagram showing the positions and rotation directions of each joint of the seven-degree-of-freedom redundant robotic arm.

[0071] Figure 4 This is a schematic diagram of the coordinate system of a six-DOF robot at the master end.

[0072] Figure 5 This is a schematic diagram of the coordinate system of the lunar rover.

[0073] Figure 6 This is a schematic diagram of the robotic arm's coordinate system. Detailed Implementation

[0074] This embodiment provides a teleoperation method for a lunar exploration mobile robotic arm based on single master-end adaptive switching. The embodiment employs a teleoperation system platform. Hardware-wise, the master-end six-DOF robot uses the Phantom Omni force feedback device, and the slave end uses the Rokae xMate ER7 Pro. Network connectivity utilizes a local area network built with a router. The software platform is based on the open-source robot operating system ROS, and the algorithm is implemented using Visual Studio Code.

[0075] The master-end six-DOF robot specifically refers to the master-end six-DOF robotic arm; the slave-end seven-DOF redundant robotic arm includes a slave-end lunar rover and a slave-end seven-DOF redundant robotic arm. The base of the slave-end seven-DOF redundant robotic arm is mounted on the front end of the slave-end lunar rover, and an end effector and force sensor are installed at the end of the slave-end seven-DOF redundant robotic arm. A lidar is installed at the front end of the mobile platform; the master-end computer and the slave-end computer communicate wirelessly through the ROS topic mechanism, and the slave-end computer connects to the slave-end lunar rover, the seven-DOF redundant robotic arm, the force sensor, and the lidar. Figure 1 As shown, the master computer collects the joint angles of the six-DOF robot's end effector and performs analytical and mapping calculations. Then, it sends control signals to the slave computer to control the speed or position of the slave robot. Simultaneously, the slave computer collects force sensor information from the robot arm's end effector, calculates virtual forces, and feeds them back to the master computer.

[0076] The teleoperation method for a lunar exploration mobile robotic arm based on single master-end adaptive switching provided in this embodiment includes the following steps:

[0077] Step 1: Establish kinematic models of the master and slave robots, including kinematic models of the master six-DOF robot, the slave lunar rover, and the seven-DOF redundant manipulator.

[0078] The end effector position of the aforementioned master-end six-degree-of-freedom robot , , Specifically as follows:

[0079]

[0080]

[0081] In this embodiment of the invention, the master-end six-DOF robot employs a six-DOF manipulator. All mapping modes use the end-effector position in Cartesian coordinates as input, specifically the geometric center of the fourth joint of the manipulator. Therefore, the kinematic modeling of the master-end six-DOF robot only utilizes the angles of the first three joints. The master-end computer collects the angles of the first three joints of the master-end six-DOF robot. , , The end effector position of the six-DOF robot was calculated analytically based on the above kinematic relationships.

[0082] like Figure 2 As shown, based on Ackerman steering geometry, the forward speed of the lunar rover from the other end is... and rotational angular velocity Its kinematic relationship with its ten joints is as follows:

[0083]

[0084]

[0085] Based on the aforementioned inverse kinematics relationship, the slave computer will receive the mobile platform's forward speed from the master computer. and rotational angular velocity The commands are parsed and calculated into control instructions for the ten joints of the mobile platform and then sent to the mobile platform's driver.

[0086] The kinematic model of the seven-degree-of-freedom redundant robotic arm is as follows:

[0087]

[0088]

[0089]

[0090] The joints of the robotic arm, such as Figure 3 As shown, the velocity Jacobian matrix is ​​established based on the vector product method. A mapping relationship between joint rotation vectors and end effector positions is established based on the D and H methods. In the robot arm position and velocity mapping mode, the slave computer receives the desired velocity of the end effector from the master computer. And the expected position of the end effector obtained through integration. Analytical calculation is performed as a joint angular velocity vector. The data is then sent to the actuators of each joint of the robotic arm; in the position and position mapping mode of the robotic arm, the slave computer will receive the desired position of the end effector from the master computer. And the expected speed of the end effector obtained through differentiation. Analytical calculation is performed as a joint angular velocity vector. It then sends the data to the actuators of each joint of the robotic arm, thereby enabling the tracking of the desired position at the end effector.

[0091] Step 2: Establish an asymmetric mapping model of position and velocity for the six-wheeled mobile platform of the lunar rover, and establish a hybrid asymmetric mapping model for the robotic arm that includes position-velocity and position-position mapping. Design adaptive switching coefficients to realize the autonomous switching of the mobile state and operation state of the lunar exploration robotic arm as well as the dual mapping mode of the robotic arm.

[0092] The two established asymmetric mapping models contain three mapping modes, as follows:

[0093] a) Lunar rover position and velocity mapping mode:

[0094]

[0095]

[0096] In this embodiment of the invention, the master-end six-DOF robot coordinate system is as follows: Figure 4 As shown, the vehicle coordinate system of the mobile platform at the end is as follows: Figure 5 As shown. The master computer, based on the aforementioned kinematic model, obtains the end-effector position of the six-DOF robot and further converts it into… and Then, the speed of the slave mobile platform is calculated based on the above mapping relationship and sent to the slave computer.

[0097] b) Robotic arm position and speed mapping mode:

[0098]

[0099] In this embodiment of the invention, the coordinate system of the seven-degree-of-freedom redundant robotic arm is as follows: Figure 6 As shown, the master computer obtains the end-effector position based on the kinematic model of the master six-DOF robot, and then calculates the end-effector velocity of the slave seven-DOF redundant robotic arm according to the above mapping relationship and sends it to the slave computer.

[0100] c) Robotic arm position and position mapping mode:

[0101]

[0102]

[0103] Among them, in order to meet the requirements of precise operation, The value should not be set too high; when switching from the end-of-line seven-degree-of-freedom redundant manipulator to the position and position mapping mode, the end-of-line computer collects the angles of each joint of the end-of-line seven-degree-of-freedom redundant manipulator, and obtains the end-effector position of the end-of-line seven-degree-of-freedom redundant manipulator at the initial moment of switching based on the forward kinematics of the end-of-line seven-degree-of-freedom redundant manipulator. The master computer collects the angles of the first three joints of the master robotic arm and obtains the end position of the master robotic arm at the initial switching moment based on the kinematic model of the master robotic arm. The master computer calculates the desired position of the seven-DOF redundant robotic arm end effector based on the above mapping relationship and sends it to the slave computer.

[0104] The distance from the end effector of the seven-degree-of-freedom redundant robotic arm to the target object When the distance exceeds a certain value, a position and velocity mapping mode is used to enable the robotic arm's end effector to quickly approach the target; when the distance... When gradually decreasing the position, a position-to-position mapping pattern is used to ensure the accuracy of task execution. The weighted mapping pattern is as follows:

[0105]

[0106] Due to the requirements of precise operation, the feature distance for switching between the two mapping modes of the robotic arm is small, therefore the switching factor... The design must ensure that the mapping mode can be switched quickly within a short distance range to avoid premature collision with the target object.

[0107] The switching between the mapping modes of the lunar rover and the robotic arm relies on an adaptive switching factor. , and The implementation is as follows:

[0108]

[0109] Distance between the rover and the target during the entry and exit state transition , The working space of the robotic arm and the specific task load are determined to ensure that the robotic arm is in the appropriate configuration when it reaches the target.

[0110] Step 3: Establish the force feedback model of the master-end six-DOF robot. The force feedback received by the master-end six-DOF robot includes the virtual repulsive force feedback of the slave-end seven-DOF redundant manipulator in the movement state and the virtual guiding force / real contact force feedback in the operation state.

[0111] The force feedback model of the master-end six-DOF robot is as follows:

[0112]

[0113] Among them, the virtual repulsive force feedback of the lunar rover in motion. Specifically as follows:

[0114]

[0115] Force feedback from a seven-degree-of-freedom redundant robotic arm Specifically as follows:

[0116]

[0117]

[0118] Among them, by adjusting It can alter the operator's perception of obstacles. The larger the object, the greater the repulsive force felt near the obstacle and the smaller the repulsive force felt far away. This ensures sensitive perception when close to the obstacle and reduces perception when far away to avoid interference. The radius of the near end of the obstacle is defined. By adjusting... , The magnitude of the feedback force when the operator performs fine end operations is adjusted to avoid excessive feedback force causing inconvenience to fine manipulation.

[0119] The single master-end adaptive switching teleoperation technology proposed in this invention can improve the operation efficiency by about 30% compared with the widely used "mobile-wait" ground teleoperation mode, and significantly improve the operation experience while reducing the operator's decision-making burden.

[0120] This invention provides a teleoperation method for a lunar exploration mobile robotic arm based on single master-end adaptive switching. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A teleoperation method for a lunar exploration mobile robotic arm based on single master-end adaptive switching, characterized in that, Includes the following steps: Step 1: Establish the kinematic model of the master-slave robot. The master robot is specifically a master six-DOF robot, and the slave robot is specifically a slave lunar exploration mobile robotic arm. The slave lunar exploration mobile robotic arm includes a slave lunar rover and a slave seven-DOF redundant robotic arm. Step 2: Establish an asymmetric mapping model of position and velocity for the lunar rover at the slave end, and establish a hybrid asymmetric mapping model including position and velocity and position and position mapping for the seven-DOF redundant manipulator at the slave end. Design adaptive switching coefficients to realize the autonomous switching of the movement state, operation state and manipulator dual mapping mode of the seven-DOF redundant manipulator at the slave end. In step 2, the motion state of the seven-DOF redundant robotic arm at the slave end is switched using an adaptive switching coefficient, specifically the adaptive switching factor: the forward motion state weighting factor ξ of the lunar rover at the slave end. v Steering motion state weighting factor ξ ω And the adaptive switching factor ξ from the seven-degree-of-freedom redundant manipulator. s Control the switching process between the movement state of the lunar rover and the operation state of the robotic arm. Step 3: Establish the force feedback model of the master-end six-DOF robot. The force feedback received by the master-end six-DOF robot includes the virtual repulsive force feedback of the slave-end lunar exploration mobile robotic arm in the moving state and the virtual guiding force or real contact force feedback in the operating state. In step 3, the force feedback model of the master-end six-DOF robot is as follows: f tot =ξ v f r +ξ s f s Among them, f tot Main feedback force; f r This refers to the virtual repulsive force feedback from the lunar rover during its movement; f s Force feedback from a seven-degree-of-freedom redundant robotic arm; In step 3, the virtual repulsive force feedback f of the slave lunar rover in its moving state r Specifically: Where, d ro Let be the distance vector from the obstacle to the rover at the other end, e be the natural constant, and k be the distance vector. r k R It is a positive real number; The force feedback f from the seven-degree-of-freedom redundant robotic arm s Specifically: f s =f(d st )+f e Where, d o For piecewise functions f(d) st The right intersection point of the first two segments of the function; d st f is the distance vector from the target object to the end effector. e k is the measurement value of the force sensor mounted on the end effector. s k s1 k s2 It is a positive real number.

2. The method according to claim 1, characterized in that, In step 1, the kinematic model of the master-end six-DOF robot is specifically as follows: P m =(x m y m z m ) T Among them, the end effector position P of the six-DOF robot at the master end. m This represents the calibration position of the master-end six-DOF robot, where T represents the matrix transpose, and x m y m z m These represent the position vectors from the origin to the end effector in the six-DOF robot coordinate system, respectively, in the X... m Projection on the axis, Y m Projection on the axis and Z m Projection on the axis; θ m1 θ m2 θ m3 These are the first joint angle, second joint angle, and third joint angle of the master-end six-DOF robot; θ m23 The sum of the second and third joint angles of the master-end six-DOF robot, i.e., θ m23 =θ m2 +θ m3 ;r m and h m These are the position vectors from the origin to the end effector in the six-DOF robot coordinate system, located at x... m oy m Projection on the plane and Z m Projection on the axis; l m1 and l m2 These are the lengths of the first link and the second link of the main-end six-DOF robot, respectively. The master-end six-DOF robot includes a six-DOF manipulator. All mapping modes use the end-effector position in Cartesian coordinates as input, specifically the geometric center of the fourth joint of the manipulator. Therefore, the kinematic modeling of the master-end six-DOF robot only utilizes the first three joint angles θ. m1 θ m2 θ m3 ; The master computer mounted on the master six-DOF robot collects the first three joint angles θ of the robot. m1 θ m2 θ m3 The end-effector position P of the six-DOF robot is calculated according to formula (1). m ; In step 1, the kinematic model of the lunar rover specifically includes: Based on Ackermann steering geometry, the kinematic relationship between the forward velocity v and rotational angular velocity ω of the rover and the ten joints of the rover is as follows: The ten joints of the lunar rover are the steering joints of the four front and rear wheels and the drive joints of all six wheels. θ1, θ2, θ3, and θ4 are the steering angles of the left front wheel, right front wheel, left rear wheel, and right rear wheel of the rover, respectively. ω1, ω2, ω3, ω4, ω5, and ω6 are the angular velocities of the left front wheel, right front wheel, left middle wheel, right middle wheel, left rear wheel, and right rear wheel of the rover, respectively. a d is the semi-wheelbase; w The wheel track is half the track width; r is the wheel radius. Using formula (2), the slave computer on the lunar probe mobile arm calculates the forward speed v and rotational angular velocity ω received from the master computer into control commands for the ten joints of the mobile platform and sends them to the drive unit of the slave lunar rover. In step 1, the kinematic model of the seven-DOF redundant manipulator is as follows: P as =(x as y as z as ) T P as =f s1 (θ),θ=(θ s1 ,i s2 ,i s3 ,i s4 ,i s5 ,i s6 ,i s7 ) T Among them, from the end position P of the seven-degree-of-freedom redundant robotic arm as Let x be the calibration position of the end effector of the seven-DOF redundant robotic arm. as y as z as These represent the position vectors from the origin to the end effector in the six-DOF robot coordinate system, respectively, in the X... s2 Projection on the axis, Y s2 Projection on the axis and Z s2 Projection on the axis; from the end of the seven-degree-of-freedom redundant robotic arm joint rotation angle θ = (θ s1 ,θ s2 ,θ s3 ,θ s4 ,θ s5 ,θ s6 ,θ s7 ) T Let θ be the joint rotation vector of the seven-DOF redundant robotic arm, where θ s1 θ s2 θ s3 θ s4 θ s5 θ s6 θ s7 These represent the joint angles of the first, second, third, fourth, fifth, sixth, and seventh joints of the seven-DOF redundant robotic arm from the slave end; and the nonlinear vector mapping function f of the seven-DOF redundant robotic arm from the slave end. s1 (θ) represents the mapping relationship between the joint rotation vector and the end effector position established based on the DH method; from the Jacobian J of the seven-DOF redundant manipulator. s (θ) is the velocity Jacobian matrix established based on the vector product method. For J s The Moore–Penrose generalized inverse matrix of (θ); K is a constant positive definite gain matrix; the end-effector velocity of the seven-DOF redundant robotic arm. In the robotic arm position and velocity mapping mode, the position is directly obtained after solving the mapping mode. In the robotic arm position and position mapping mode, it needs to be obtained by time differentiation. The desired position P of the end effector of the seven-degree-of-freedom redundant robotic arm is obtained from the time-dependent derivative. s In the robotic arm position and velocity mapping mode, it needs to be obtained through time integration; in the robotic arm position and position mapping mode, it can be directly obtained after solving the mapping mode; from the angular velocity of the seven-degree-of-freedom redundant robotic arm joints. Let θ represent the vector composed of the angular velocities of each joint of the seven-degree-of-freedom redundant manipulator and the differential of the joint rotation angle θ of the seven-degree-of-freedom redundant manipulator.

3. The method according to claim 2, characterized in that, In step 2, a mapping relationship between joint rotation vectors and end effector positions is established based on the DH method. The asymmetric mapping model includes a mapping mode between the lunar rover's position and velocity, and the hybrid asymmetric mapping model includes a mapping mode between the robotic arm's position and velocity and a mapping mode between positions. Specifically, it includes: The position and velocity mapping pattern of the lunar rover from the end is represented as follows: Wherein, the main end movement distance d m The current position of the master six-DOF robot is at x m oy m Distance on the plane; rotation angle θ of the main end m The current position of the master six-DOF robot and its initial zero position around Z m The angle of rotation of the axis; V r Let V be the velocity vector of the lunar rover from the end. r =(v ω) T ξ r For the adaptive switching factor of the lunar rover at the slave end; for the scaling factor K of the lunar rover at the slave end. r =(k v k ω ) T , where k v k ω These are constants for velocity and angular velocity, respectively; x m x m0 The six-DOF robot at the master end is in X m Current and initial positions in the direction, y m y m0 Y m Current and initial positions in the direction; Establish a six-DOF robot coordinate system at the master end, with the geometric center of the first joint as the origin and the Z-axis of rotation of the first joint as the Z-axis. m The axis of rotation is vertically upward, with the positive direction being vertical. When the first joint is in the zero position, the axis of rotation of the second joint is Y. m The axis is determined by the right-hand screw rule. m axis; Establish a coordinate system for the rover, with the origin at the geometric center of the rover and the direction of travel as X. s1 The axis, perpendicular to the Z-axis established from the upper surface of the lunar rover. s1 The axis, with vertically upward as the positive direction, is determined by the right-hand screw rule. s1 axis; The position and speed mapping mode of the robotic arm is represented as follows: in, v x v y v z The coordinates of the robotic arm end effector in the seven-DOF redundant robotic arm coordinate system are as follows: s2 Y s2 Z s2 Velocity component along the axial direction; ξ s The adaptive switching factor for the seven-DOF redundant robotic arm at the slave end; the scaling factor K for the seven-DOF redundant robotic arm at the slave end. s1 =(k x1 k y1 k z1 ) T , where k x1 k y1 k z1 They are respectively about X s2 Y s2 Z s2 The constant velocity in the direction; the end-effector position P of the six-DOF robot. m =(x m y m z m ) T , where x m y m , z m The positions of the robotic arm's end effector in the seven-DOF redundant robotic arm coordinate system are respectively: s2 Y s2 Z s2 Projection along the axial direction; The coordinate system of the seven-degree-of-freedom redundant robotic arm has its origin at the geometric center of the plane connecting the robotic arm and the vehicle body, and the rotation axis of the first joint of the robotic arm is X. s2 Axis, Z s2 With Z s1 With the same axis direction, Y is determined according to the right-hand screw rule. s2 axis; The position of the robotic arm and the position mapping mode are represented as follows: P.S s JP s0 +ξ s ·diag(K s2 )·ΔP m ΔP m =P m -P m0 Among them, P s =(x s y s z s ) T x s y s , z s The coordinates of the robotic arm end effector in the seven-DOF redundant robotic arm coordinate system are as follows: s2 Y s2 Z s2 Position component along the axis; K s2 K is a constant proportionality factor. s2 =(k x2 k y2 k z2 ) T k x2 k y2 k z2 X s2 Y s2 Z s2 Gain factors in the three axial directions; P s0 P represents the initial position of the end effector of the seven-DOF redundant manipulator when switching from the position-to-position mapping mode; m0 Let ΔP be the end effector position of the master end-6 robot at the initial moment when switching from the seven-DOF redundant manipulator to the position and position mapping mode. m The position of the robotic arm's end effector changes after switching from mapping mode to position and position mapping mode; In the robotic arm position and speed mapping mode, the slave computer will receive the desired speed of the end effector from the master computer. And the expected position P of the end effector obtained through integration. s Analytical calculation is performed as a joint angular velocity vector. And it sends the information to the actuators of each joint of the robotic arm; in the position and position mapping mode of the robotic arm, the slave computer will receive the desired position P of the end effector from the master computer. s And the expected speed of the end effector obtained through differentiation. Analytical calculation is performed as a joint angular velocity vector. It then sends the commands to the actuators of each joint of the robotic arm, thereby enabling the tracking of the desired position at the end effector.

4. The method according to claim 3, characterized in that, In step 2, the hybrid asymmetric mapping model, combined with the switching control strategy, is designed with the following weighted mapping of the hybrid mapping mode: Where s is a complex variable, D is a switching factor, and D = f s2 (d,x m ), f s2 (·) indicates that the expression relates to d and x m The nonlinear function is d, where d is the distance between the seven-degree-of-freedom redundant manipulator and the target. When d decreases to 2cm to 5cm, D gradually decreases from 1 to 0, and the manipulator switches from position and velocity mapping mode to position and position mapping mode.

5. The method according to claim 4, characterized in that, Step 2 includes: Define the time-varying interval of the adaptive switching factor as the switching state, and denote the distance between the lunar rover and the target when entering the switching state as d. t When leaving the switching state, the distances between the lunar rover and the target are d. l When the distance d between the lunar rover and the target is greater than d t At this time, the adaptive switching factor ξ of the seven-degree-of-freedom redundant robotic arm is... s =0, weighting factor ξ for the forward motion state of the lunar rover. v =1, weighting factor ξ for the turning motion state of the lunar rover. ω =1, the seven-DOF redundant robotic arm at the slave end is in a moving state; when the distance d between the lunar rover and the target at the slave end is less than d... t And greater than d l At that time, ξ s Gradually increasing to 1, while ξ v ξ ω Gradually decreasing to 0, the seven-DOF redundant manipulator gradually switches from the movement state of the slave lunar rover to the manipulation state of the manipulator; when the distance d between the slave lunar rover and the target is less than d... l At this time, ξ s =1, ξ v =0, ξ ω =0, the redundant robotic arm with seven degrees of freedom is in the operating state.

6. The method according to claim 5, characterized in that, The forward motion state weighting factor ξ of the slave lunar rover v Steering motion state weighting factor ξ ω And the adaptive switching factor ξ from the seven-degree-of-freedom redundant manipulator. s Specifically: Where f1(·) represents the expression with respect to d m The nonlinear function of d, f2(·) represents the expression with respect to θ. m ξ v The nonlinear function is f3(·), which represents a nonlinear function with respect to d.

7. An electronic device, characterized in that, It includes a processor and a memory, the memory storing program code that, when executed by the processor, causes the processor to perform the steps of the method as described in any one of claims 1 to 6.

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