Patents by Inventor Yizhang Liu

Yizhang Liu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11938635
    Abstract: A motion control method, a robot controller, and a computer readable storage medium are provided. The method includes: calculating an inverse Jacobian matrix of a whole-body generalized coordinate vector at a current time relative to an actual task space vector of a humanoid robot; calculating a target generalized coordinate vector corresponding to a to-be-executed task space vector at a current moment by combining an actual task space vector and the to-be-executed task space vector into a null space of the inverse Jacobian matrix according to preset position constraint(s) corresponding to the whole-body generalized coordinate vector; and controlling a motion state of the humanoid robot according to the target generalized coordinate vector. In this manner, the motion of the humanoid robot is optimized as a whole to achieve the purpose of controlling the humanoid robot to avoid the limits of the motion of joints.
    Type: Grant
    Filed: March 24, 2022
    Date of Patent: March 26, 2024
    Assignee: UBTECH ROBOTICS CORP LTD
    Inventors: Zhihao Zhang, Yizhang Liu, Jinliang Chen, Youjun Xiong
  • Patent number: 11926052
    Abstract: A robot control method includes: acquiring distances between a center of mass (COM) of the biped robot and each of preset key points of feet of the biped robot, and acquiring an initial position of the COM of the biped robot; calculating a position offset of the COM based on the distances; adjusting the initial position of the COM based on the position offset of the COM to obtain a desired position of the COM of the biped robot; and determining desired walking parameters of the biped robot based on the desired position of the COM by using a preset inverse kinematics algorithm, wherein the desired walking parameters are configured to control the biped robot to walk.
    Type: Grant
    Filed: December 23, 2020
    Date of Patent: March 12, 2024
    Assignee: UBTECH ROBOTICS CORP LTD
    Inventors: Chunyu Chen, Yizhang Liu, Ligang Ge, Zheng Xie, Youjun Xiong, Jianxin Pang
  • Patent number: 11926056
    Abstract: A gait planning method and a robot using the same as well as a computer readable storage medium are provided. The method includes: determining a reference leg length l0 and a leg length variation range A of a robot; performing a trajectory planning on a length of at least one of the legs of the robot using; an equation including the reference leg length, the leg length variation range, and a preset recurrent excitation function of a time variable t. In this manner, the trajectory planning for the leg length of the robot during motion is performed according to the characteristics of motion scene such as robot jumping or running so that the change of the leg length of the robot is adapted to the motion process, which greatly improves the stability of the robot in the motion scene such as jumping or running.
    Type: Grant
    Filed: February 23, 2022
    Date of Patent: March 12, 2024
    Assignee: UBTECH ROBOTICS CORP LTD
    Inventors: Jie Bai, Yizhang Liu, Ligang Ge, Chunyu Chen, Qiuyue Luo, Youjun Xiong
  • Patent number: 11904472
    Abstract: A humanoid robot control method, a mobile machine using the same, and a computer readable storage medium are provided. The method includes: mapping posture information of leg joints of a human body to leg joint servos of a humanoid robot to obtain an expected rotation angle and an expected rotation angular velocity of non-target optimized joint servos of the leg joint servos and an expected rotation angle and an expected rotation angular velocity of target optimized joint servos of the leg joint servos; obtaining an optimization objective function corresponding to the target optimized joint servos of the leg joint servos; optimizing the expected rotation angle and the expected rotation angular velocity of the target optimized joint servos to obtain a corrected expected rotation angle and a corrected expected rotation angular velocity of the target optimized joint servos; and controlling each of the leg joint servos of the humanoid robot.
    Type: Grant
    Filed: October 19, 2021
    Date of Patent: February 20, 2024
    Assignee: UBTECH ROBOTICS CORP LTD
    Inventors: Jie Bai, Ligang Ge, Yizhang Liu, Youjun Xiong
  • Patent number: 11878426
    Abstract: A biped robot gait control method as well as a robot and a computer readable storage medium are provided. During the movement, the system obtains a current supporting pose of a current supporting leg of the biped robot, and calculates a relative pose between the supporting legs based on the current supporting pose and a preset ideal supporting pose of a next step. The system further calculates modified gait parameters of the next step based on the relative pose between the two supporting legs and a joint distance between left and right ankle joints in an initial state of the biped robot when standing. Finally, the system controls the next supporting leg to move according to the modified gait parameters.
    Type: Grant
    Filed: May 6, 2021
    Date of Patent: January 23, 2024
    Assignee: UBTECH ROBOTICS CORP LTD
    Inventors: Xingxing Ma, Chunyu Chen, Ligang Ge, Hongge Wang, Mingqiang Huang, Jiangchen Zhou, Yizhang Liu, Zheng Xie, Youjun Xiong
  • Publication number: 20240017404
    Abstract: A robot step length control method, a robot controller, and a computer-readable storage medium are provided. The method includes: if it detects that a humanoid robot is not in a balanced state at a current time, it correspondingly obtains a torso deflection posture parameter, a lower limb parameter and a leg swing frequency of the legs of the humanoid robot at the current time; and it calculates, using a swinging leg capture point algorithm, a calculated step length for maintaining a stable state of the humanoid robot that meets a posture balance requirement of the robot at the current time based on the torso deflection posture parameter, the lower limb parameter, and the leg swing frequency, so that the humanoid robot can be restored to the balanced state after moving with the calculated step length, thereby improving the anti-interference ability of the robot.
    Type: Application
    Filed: September 22, 2023
    Publication date: January 18, 2024
    Inventors: Chunyu Chen, Yizhang Liu, Ligang Ge, Zheng Xie, Youjun Xiong
  • Publication number: 20240001558
    Abstract: A robot calibration method, a robot, and a computer-readable storage medium are provided. The method includes: obtaining operation space information of the execution end of the robot; obtaining operation space points after gridding an operation space of the robot by gridding the operation space based on the operation space information; obtaining calibration data by controlling the execution end to move to the operation space points meeting a preset requirement; and calibrating the hand and the image detection device of the robot based on the obtained calibration data. In this manner, the operation space points are determined by gridding the operation space based on the operation space information, and the execution end can be automatically controlled to move to the operation space points that meet the preset requirements so as to obtain the calibration data in an automatic and accurate manner, thereby simplifying the calibration process and improving the efficiency.
    Type: Application
    Filed: September 19, 2023
    Publication date: January 4, 2024
    Inventors: SHUO ZHANG, Zheng Xie, Yizhang Liu, Zhihao Zhang, Yingfu Zeng, Youjun Xiong
  • Publication number: 20240001546
    Abstract: A robotic arm angle interval inverse solving method and a robotic arm using the same are provided. The method includes: obtaining a joint angle calculation model and a differential relationship model of a target joint of the robotic arm; obtaining extreme arm angles corresponding to a joint angle of the differential relationship model at extreme values based on the differential relationship model; obtaining a joint arm angle interval corresponding to the target joint based on the extreme arm angle and the joint angle calculation model; and obtaining a target arm angle interval corresponding to the robotic arm based on the joint arm angle interval corresponding to the target joint of the robotic arm. In comparison with the existing method to solve the arm angle interval of the robotic arm, a more accurate arm angle interval can be obtained.
    Type: Application
    Filed: September 18, 2023
    Publication date: January 4, 2024
    Inventors: ZHIHAO ZHANG, Yizhang Liu, Jinliang Chen, Youjun Xiong
  • Publication number: 20230415333
    Abstract: A center of mass (COM) planning method includes: obtaining a planning position of the COM and a planning speed of the COM of a robot, and calculating a planning capture point of the robot according to the planning position of the COM and the planning speed of the COM; obtaining a measured position of the COM and a measured speed of the COM, and calculating a measured capture point of the robot according to the measured position the measured speed; calculating a desired zero moment point (ZMP) of the robot based on the planning capture point and the measured capture point; obtaining a measured ZMP of the robot, and calculating an amount of change in a position of the COM according to the desired ZMP and the measured ZMP; and correcting the planning position of the COM according to the amount of change in the position of the COM.
    Type: Application
    Filed: September 19, 2023
    Publication date: December 28, 2023
    Inventors: Ligang Ge, Yizhang Liu, Chunyu Chen, Zheng Xie, Youjun Xiong
  • Patent number: 11833692
    Abstract: The present disclosure provides a method for controlling an arm of a robot, including obtaining obstacle information relating to the arm of the robot by at least one sensor, obtaining current posture information of the arm of the robot by a least one detector and obtaining an expected posture information of an end-portion of the arm of the robot, determining an expected trajectory of the end-portion of the arm of the robot, determining an expected speed of the end-portion of the arm of the robot in accordance with the expected trajectory of the end-portion, determining a virtual speed of a target point on the arm of the robot, and configuring a target join speed corresponding to a joint of the arm of the robot. Such that the redundant arm of the robot may be configured to prevent from contacting the obstacles in the complex environment while performing corresponding tasks.
    Type: Grant
    Filed: December 8, 2020
    Date of Patent: December 5, 2023
    Assignee: UBTECH ROBOTICS CORP LTD
    Inventors: Dake Zheng, Yizhang Liu, Zheng Xie, Jianxin Pang, Youjun Xiong
  • Publication number: 20230359207
    Abstract: A trajectory planning method, a computer-readable storage medium, and a robot are provided. The method includes: constructing a phase variable of a trajectory planning of a robot, where the phase variable is a function of two position components of a torso of the robot on a horizontal plane; and performing, using the phase variable replacing a time variable, the trajectory planning on a swinging leg of the robot in each preset coordinate axis direction. In this manner, the robot can no longer continue to follow the established trajectory after being disturbed by the environment, but make state adjustments according to the disturbance received to offset the impact of the disturbance, thereby maintaining walking stability and avoiding the problem of early or late landing of the swinging leg.
    Type: Application
    Filed: July 16, 2023
    Publication date: November 9, 2023
    Inventors: QIUYUE LUO, Ligang Ge, Yizhang Liu, Jie Bai, Youjun Xiong
  • Publication number: 20230278212
    Abstract: A gait planning method for a robot includes: constructing a first phase variable of a gait planning of the robot, wherein the first phase variable is a function of two position components of a torso of the robot on a horizontal plane; constructing a second phase variable based on the first phase variable, wherein the second phase variable is a function of the first phase variable, and a slope of the second phase variable is smaller than a slope of the first phase variable when a foot of a swing leg of the robot starts to touch a support surface; and performing the gait planning on the foot of the swing leg using the second phase variable to obtain a planned trajectory of the foot of the swing leg.
    Type: Application
    Filed: December 29, 2022
    Publication date: September 7, 2023
    Inventors: QIUYUE LUO, Yizhang Liu, Ligang Ge, Chunyu Chen, Jiangchen Zhou, Meng Yen
  • Publication number: 20230271656
    Abstract: A robot state estimation method, a computer-readable storage medium, and a legged robot are provided. The method includes: obtaining force information of a left leg of a robot and a right leg of the robot; calculating a ZMP of the robot in a world coordinate system based on the force information of the left leg and the force information of the right leg; and calculating a position of a center of mass (CoM) of the robot based on a preset linear inverted pendulum model. In this manner, a brand-new linear inverted pendulum model is constructed in advance, which uses the ZMP of the robot as a supporting point of the model, thereby fully considering the influence of the change of the position of the ZMP of the robot on the position of the CoM.
    Type: Application
    Filed: May 5, 2023
    Publication date: August 31, 2023
    Inventors: Ligang Ge, Yizhang Liu, Chunyu Chen, Zheng Xie, Youjun Xiong
  • Publication number: 20230266764
    Abstract: A path generation method for a robot includes: based on a scene model of a current scene and a machine model corresponding to the robot, combined with multiple configurations of the robot, determining a plurality of initial points between a start point and an end point in the scene model; removing redundant points from the plurality of the initial points to obtain necessary points among the initial points; and connecting the necessary points to obtain a path between the start point and the end point.
    Type: Application
    Filed: February 24, 2023
    Publication date: August 24, 2023
    Inventors: ZHIHAO ZHANG, Yizhang Liu, Huan Tan, Youjun Xiong
  • Publication number: 20230234655
    Abstract: A robot step control method, a robot control apparatus, and a storage medium are provided. The method includes: determining an expected support force of two legs of a biped robot according to zero-moment point planning data and actual position data of the two legs at a current moment, and determining a current desired joint posture angle of ankle joints of the two legs and a desired joint position matching an actual leg support state using a compliance control algorithm based on an expected support force of the two legs, and centroid movement planning data, centroid actual movement data, step planning data and actual force data of the two legs at the current moment. In such manner, all-direction compliant controls can be performed on a desired leg pose condition according to the actual motion status of the biped robot, thereby improving the walking stability and terrain adaptability of the biped robot.
    Type: Application
    Filed: December 29, 2022
    Publication date: July 27, 2023
    Inventors: Ligang Ge, Yizhang Liu, Qiuyue Luo, Chunyu Chen, Xuan Luo, Jiangchen Zhou
  • Patent number: 11693430
    Abstract: A computer-implemented gait planning method includes: determining a pitch angle between a foot of the robot and a support surface where the robot stands; determining a support point on a sole of the foot according to the pitch angle; calculating an ankle-foot position vector according to the support point, wherein the ankle-foot position vector is a position vector from an ankle of the robot to a support point on a sole of the foot; calculating a magnitude of change of an ankle position according to the pitch angle and the ankle-foot position vector; and obtaining a compensated ankle position by compensating the ankle position according to the magnitude of change of the ankle position.
    Type: Grant
    Filed: December 8, 2020
    Date of Patent: July 4, 2023
    Assignee: UBTECH ROBOTICS CORP LTD
    Inventors: Jie Bai, Ligang Ge, Yizhang Liu, Hongge Wang, Jianxin Pang, Youjun Xiong
  • Patent number: 11691284
    Abstract: A robot control method includes: obtaining force information associated with a left foot and a right foot of the robot; calculating a zero moment point of a COM of a body of the robot based on the force information; updating a motion trajectory of the robot according to the zero moment point of the COM of the body to obtain an updated position of the COM of the body; performing inverse kinematics analysis on the updated position of the COM of the body to obtain joint angles of a left leg and a right leg of the robot; and controlling the robot to move according to the joint angles.
    Type: Grant
    Filed: December 13, 2020
    Date of Patent: July 4, 2023
    Assignee: UBTECH ROBOTICS CORP LTD
    Inventors: Chunyu Chen, Yizhang Liu, Ligang Ge, Zheng Xie, Hongge Wang, Youjun Xiong, Jianxin Pang
  • Publication number: 20230202027
    Abstract: A walking control method for a biped robot includes: detecting whether the biped robot is in an unbalanced state; in response to detection that the biped robot is in the unbalanced state, obtaining a predicted balance step length corresponding to the biped robot in the unbalanced state; performing a smooth transition processing on the predicted balance step length according to a current movement step length of the biped robot to obtain a desired balance step length corresponding to the predicted balance step length; determining a planned leg trajectory of the biped robot according to the desired balance step length; and controlling a current swing leg of the biped robot to move according to the planned leg trajectory.
    Type: Application
    Filed: December 28, 2022
    Publication date: June 29, 2023
    Inventors: CHUNYU CHEN, Jie Bai, Yizhang Liu, Ligang Ge, Zheng Xie, Youjun Xiong
  • Publication number: 20230191606
    Abstract: A collision detection method, a storage medium, and a robot are provided. The method includes: calculating an external torque of a first joint of the robot based on a preset generalized momentum-based disturbance observer; calculating an external torque of a second joint of the robot based on a preset long short-term memory network; calculating an external torque of a third joint of the robot based on the external torque of the first joint and the external torque of the second joint; and determining whether the robot has collided with an external environment or not based on the external torque of the third joint and a preset collision threshold. In the present disclosure, the component of the model error in the joint external torque calculated by the disturbance observer is eliminated to obtain the accurate contact torque, thereby improving the accuracy of the collision detection.
    Type: Application
    Filed: December 6, 2022
    Publication date: June 22, 2023
    Inventors: Meihui Zhang, Yizhang Liu, Youjun Xiong, Huan Tan
  • Publication number: 20230191604
    Abstract: A robot stability control method includes: obtaining a desired zero moment point (ZMP) and a fed-back actual ZMP of a robot at a current moment; based on a ZMP tracking control model, the desired ZMP and the actual ZMP, calculating a desired value of a motion state of a center of mass of the robot at the current moment, wherein the desired value of the motion state of the center of mass comprises a correction amount of the position of the center of mass; based on a spring-mass-damping-acceleration model and the desired value of the motion state of the center of mass, calculating a lead control input amount for the correction amount of the position of the center of mass; and controlling motion of the robot according to the lead control input amount and a planned value of the position of the center of mass at the current moment.
    Type: Application
    Filed: November 29, 2022
    Publication date: June 22, 2023
    Inventors: Ligang Ge, Yizhang Liu, Chunyu Chen, Qiuyue Luo, Jiangchen Zhou, Meng Yan, Youjun Xiong