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CN-122008149-A - Six-degree-of-freedom parallel self-stabilization platform for four-legged robot and control system

CN122008149ACN 122008149 ACN122008149 ACN 122008149ACN-122008149-A

Abstract

The invention relates to the technical field of motion control of mobile robots, and particularly discloses a six-degree-of-freedom parallel self-stabilization platform for a quadruped robot and a control system. Each group of branched chains comprises a driving device on the static platform, a rudder arm connected with the driving device, a driving connecting rod and a driven connecting rod, wherein the driving device, the rudder arm, the driving connecting rod and the driven connecting rod form a closed-loop structure through a spherical hinge so as to drive the movable platform to realize six-degree-of-freedom motion. The platform has the advantages of being flat and compact in structure, capable of being directly and rigidly mounted on the back of the robot, reducing the gravity center of additional load, avoiding damaging the motion balance of the quadruped robot, having the characteristics of high rigidity, high bearing capacity and light weight, and being specially designed for the back space optimization of the mobile robot.

Inventors

  • ZHANG HETONG
  • YU YANG
  • ZHANG KAIMING
  • Peng Kunen
  • XIE JINGCHANG

Assignees

  • 北京航空航天大学

Dates

Publication Date
20260512
Application Date
20260317

Claims (10)

  1. 1. A six degree of freedom parallel self-stabilizing platform for a four-legged robot, comprising: the static platform is arranged at the back of the quadruped robot (1); a movable platform (10) arranged in parallel with the stationary platform and used for bearing a load; The driving branched chains are in a plurality of groups and are circumferentially and uniformly distributed and connected between the static platform and the movable platform (10) and used for driving the movable platform (10) to do six-degree-of-freedom motion relative to the static platform; Wherein each set of said driving branches comprises: the driving device (4) is fixedly arranged on the static platform; The rudder arm (7) is arranged at the output end of the driving device (4); One end of the driving connecting rod (6) is connected with the free end of the steering engine arm (7); One end of the driven connecting rod (8) is hinged with the other end of the driving connecting rod (6) through a lower spherical hinge (5), and the other end of the driven connecting rod (8) is hinged with the movable platform (10) through an upper spherical hinge (9).
  2. 2. Six degree of freedom parallel self-stabilizing platform for quadruped robots according to claim 1, characterized in that the static platform consists of a first lower platform (3) and a second lower platform (13) arranged up and down; the first lower platform (3) is mounted on the back of the quadruped robot (1) through a fixed connecting piece (2); The driving devices (4) are arranged between the first lower platform (3) and the second lower platform (13).
  3. 3. Six degree of freedom parallel self stabilizing platform for a four foot robot according to claim 2, further comprising a controller mount (12) fixed to the second lower platform (13) for mounting an embedded controller controlling the drive means (4).
  4. 4. Six degree of freedom parallel self stabilizing platform for four legged robots according to claim 1, characterized in that the moving platform (10) is provided with sensor mounting (11) for mounting inertial measurement units.
  5. 5. A control system for a six degree of freedom parallel self-stabilizing platform for a four-legged robot, applied to a platform according to any one of claims 1 to 4, comprising: the sensing module is used for acquiring the motion gesture data of the quadruped robot body in real time; The main control module is arranged in the quadruped robot and is used for calculating the target deflection angles of the driving devices (4) required for keeping the target posture of the movable platform (10) according to the motion posture data; The driving control module is in communication connection with the main control module and is used for receiving the target deflection angle and generating a corresponding multipath PWM driving signal; and the execution module comprises a plurality of driving devices (4) which are used for responding to the PWM driving signals to rotate so as to drive the movable platform (10) to move.
  6. 6. The control system for a six degree of freedom parallel self-stabilizing platform of a four-legged robot of claim 5, wherein, The process of calculating the target deflection angle by the main control module comprises posture compensation calculation: Set up base coordinate system Is fixed on the static platform, and a platform coordinate system Is fixed on the movable platform (10) and is in a world coordinate system Is a ground inertial reference system; Acquiring a rotation matrix of a current base coordinate system relative to a world coordinate system from a bottom layer of the quadruped robot (1) ; In order to keep the mobile platform (10) horizontal in world coordinate system, the rotation matrix of the mobile platform relative to world coordinate system is required to be satisfied Wherein Is a unit matrix, and Wherein A rotation matrix of the movable platform (10) relative to a base coordinate system; The relative rotation compensation matrix required by the movable platform (10) for compensating the motion of the robot is calculated as follows: 。
  7. 7. the control system for a six degree-of-freedom parallel self-stabilizing platform of a four-legged robot according to claim 6, wherein the master control module is further configured to perform an inverse kinematics solution: According to the rotation matrix And the target position of the center of the movable platform (10) under the base coordinate system Calculating the first of the movable platform (10) Target coordinates of the upper spherical hinges (9) under the base coordinate system Wherein The fixed coordinates of the hinge points of the upper spherical hinge (9) under a platform coordinate system are obtained; Based on the geometrical constraint relation of the ith driving branched chain, the target deflection angle of the driving device (4) is calculated Wherein L, M, N are defined by the target coordinates Steering engine rotation center coordinate And the length a of the steering arm (7) and the length s of the driven connecting rod (8).
  8. 8. The control system for a six degree of freedom parallel self-stabilizing platform of a four-legged robot of claim 5, wherein the control flow executed by the master control module comprises: performing low-pass filtering processing on body posture data acquired from a bottom layer of the four-foot robot; calculating deviation between the filtered attitude data and the target attitude, and calculating an attitude correction amount through a proportional, integral and differential controller; Substituting the attitude correction amount into an inverse kinematics model, and calculating to obtain target deflection angles of the six driving devices (4); Mapping the target deflection angle into a PWM pulse width value and sending the PWM pulse width value to the driving control module; The driving control module analyzes the received PWM pulse width value and outputs six paths of PWM signals to drive the driving device (4) to act.
  9. 9. The control system for the six-degree-of-freedom parallel self-stabilization platform of the quadruped robot of claim 5, wherein the main control module is an onboard computer carried in the quadruped robot, the drive control module is an ESP32 microcontroller, and the two are communicated through a USB serial communication interface.
  10. 10. The control system for a six degree of freedom parallel self-stabilizing platform of a four-legged robot according to claim 5, wherein the main control module obtains body posture data by calling a Software Development Kit (SDK) interface of the four-legged robot (1).

Description

Six-degree-of-freedom parallel self-stabilization platform for four-legged robot and control system Technical Field The invention relates to the technical field of motion control of mobile robots, in particular to a six-degree-of-freedom parallel self-stabilization platform for a four-legged robot and a control system. Background With the wide application of the quadruped robot in complex scenes such as field survey, post-disaster rescue, logistics transportation, mobile inspection and the like, the requirements of the carried task load (such as a tripod head camera, a laser radar, a high-precision instrument or a liquid sample) on the operation stability are increasingly prominent. However, the prior art scheme has the defects that a passive damping mechanism (such as a rubber damping ball or a spring damping system) mainly absorbs high-frequency micro-vibration when dealing with large-amplitude gesture disturbance generated by robot motion, the inherent low-frequency and large-amplitude gesture inclination (such as climbing, pitching and turning and rolling) compensation capability is limited in walking, the serial three-axis cradle head is commonly used for stabilizing, but has weak cantilever structure rigidity, the integral gravity center is raised by multi-axis serial connection, so that the motion balance of a quadruped robot is not facilitated, in addition, the traditional industrial six-degree-of-freedom parallel platform is huge, depends on upper computer control and is difficult to directly transplant into a limited space on the back of the quadruped robot. In the motion process of the four-foot robot, the robot body can generate complicated six-degree-of-freedom pose disturbance, especially in pitching and rolling. If the load platform is only fixedly installed or simply passively damped, the load attitude level is difficult to maintain, and further image blurring, data abnormality or load tilting are caused. Although there have been studies to isolate vibration using parallel mechanisms, there is currently no lightweight active stabilization solution that is designed specifically for four-legged robot back space, integrated with embedded controls, and capable of decoupling from the robot body motion. Specifically, the six-degree-of-freedom Stewart platform is miniaturized and is adapted to the back of the quadruped robot, a complete technical scheme for realizing full-closed-loop active stabilization through cooperation of a machine and a control system by adopting a low-cost controller (such as an ESP 32) and combining an inverse kinematics algorithm is still to be proposed. Therefore, a back active stable platform system which has compact structure, high rigidity and quick response and can adapt to severe motion environment of the four-legged robot is needed. Disclosure of Invention In order to achieve the purpose of the application, the application provides a six-degree-of-freedom parallel self-stabilization platform for a four-legged robot, which is characterized by comprising the following components: The static platform is arranged at the back of the quadruped robot; The movable platform is arranged in parallel with the static platform and is used for bearing a load; the driving branched chains are in a plurality of groups and are circumferentially and uniformly distributed and connected between the static platform and the movable platform and used for driving the movable platform to do six-degree-of-freedom motion relative to the static platform; Wherein each set of said driving branches comprises: the driving device is fixedly arranged on the static platform; The rudder arm is arranged at the output end of the driving device; One end of the driving connecting rod is connected with the free end of the rudder horn; one end of the driven connecting rod is hinged with the other end of the driving connecting rod through a lower spherical hinge, and the other end of the driven connecting rod is hinged with the movable platform through an upper spherical hinge. In some embodiments, the static platform is composed of a first lower platform and a second lower platform which are arranged above each other; the first lower platform is mounted on the back of the quadruped robot through a fixed connecting piece; The driving devices are arranged between the first lower platform and the second lower platform. In some embodiments, the controller mounting member is fixed to the second lower platform and is used for mounting an embedded controller for controlling the driving device. In some embodiments, a sensor mounting is provided on the mobile platform for mounting an inertial measurement unit. To achieve the same object, the present application also provides a control system for a six-degree-of-freedom parallel self-stabilization platform for a quadruped robot, which is applied to the platform of any one of the above specific embodiments, and is characterized by comprising: the sensing module is used