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JP-2026514522-A - Methods, apparatus, robots, and storage media for planning and controlling legged robots.

JP2026514522AJP 2026514522 AJP2026514522 AJP 2026514522AJP-2026514522-A

Abstract

This application relates to the field of robotics, and more particularly to a planning and control method, apparatus, robot, and storage medium for a legged robot. The method includes the steps of: determining the foot end reference state of each leg based on the motion state of the legged robot and the next time swing parameter of each leg; planning a swing leg trajectory with collision awareness based on a foot end dynamics model and a discrete collision model for the leg that will start swinging in the next time; and controlling the entire legged robot based on the motion state, reference state sequence, and foot end reference state. In this method, if a leg is planned to be a support leg and the support leg is not in contact with the ground, collision-aware whole-body control is performed based on a whole-body dynamics model and a discrete collision model. This solves the problem in related technologies where passive flexible cushioning of collisions in legged robots is limited, the calculation of the control algorithm is large, the control accuracy is low, the degree of wear on the robot hardware is relatively high, the service life is short, and it is not possible to meet actual demands.

Inventors

  • ジャオ ミングオ
  • ツァイ ウェンハン
  • パン イエンボー
  • ハン シンユー

Assignees

  • 清華大学

Dates

Publication Date
20260511
Application Date
20240105
Priority Date
20231113

Claims (12)

  1. A method for planning and controlling a legged robot, Steps to acquire motion commands and motion status of a legged robot, The steps include generating a reference state sequence for the legged robot and the next time swing parameter for each leg based on the motion command and the motion state, Based on the aforementioned motion state and the next time swing parameters for each leg, the foot end reference state of each leg is determined, and for the leg that starts swinging at the next time, a swing leg trajectory with collision awareness is planned based on the foot end dynamics model and the discrete collision model so that the effects that occur after the early collision are within the target constraint range. A method for planning and controlling a legged robot, comprising the steps of controlling the entire legged robot based on the motion state, the reference state sequence, and the foot end reference state, wherein, when a support leg is planned to be a support leg and the support leg is not in contact with the ground, collision-aware whole-body control is performed based on a whole-body dynamics model and a discrete collision model so that the effects that occur after a delayed collision are within the target constraint range.
  2. The planning and control method for a legged robot as described in feature 1.
  3. The step of planning a swing leg trajectory with collision awareness based on the foot-end dynamics model and the discrete collision model is: Steps include obtaining pre-set state variables and target constraints, The steps include constructing a continuous-time trajectory optimization problem for the leg that starts swinging at the next time step, based on the foot-end dynamics model, the preset state variables, and the target constraints, A method for planning and controlling a legged robot according to claim 1 or 2, characterized by comprising the step of discretizing the continuous-time trajectory optimization problem, obtaining a discrete-time trajectory optimization problem for the swing leg foot, and solving the problem to obtain a swing leg trajectory that is collision-aware.
  4. The method for planning and controlling a legged robot according to claim 3, characterized in that the preset state quantities include one or more of the initial state of the swing leg's foot, the landing state of the swing leg's foot, the duration of the swing, and the desired maximum ground clearance of the swing leg's foot, and the target constraints include one or more of the state equation constraint, driving force inequality constraint, trajectory altitude inequality constraint, initial state equation constraint, terminal state equation constraint, collision awareness inequality constraint, and terminal velocity direction inequality constraint.
  5. The planning and control method for a legged robot according to feature 3.
  6. The planning and control method for a legged robot as described in feature 1.
  7. The planning and control method for a legged robot according to claim 1, characterized in that the tasks simultaneously processed by the whole-body control include multiple tasks from among torso trajectory tracking tasks, foot trajectory tracking tasks, plantar force tracking tasks, minimizing joint moment change tasks, and minimizing plantar force change tasks, and the constraints simultaneously processed by the collision-aware whole-body control include multiple constraints from among floating-based dynamic equation constraints, plantar force inequality constraints, joint output moment saturation inequality constraints, joint rotation speed saturation inequality constraints, joint output power saturation inequality constraints, and collision awareness constraints.
  8. The step of controlling the entire body of the foot-type robot based on the aforementioned motion state, the aforementioned reference state sequence, and the aforementioned foot end reference state is: The steps include setting a foot-end trajectory tracking task that follows the swing leg trajectory with collision awareness, determining that the swing leg should be the swing leg in the plan, setting the target plantar force of the plantar force tracking task to a predetermined value, setting the plantar force constraint in the plantar force inequality constraint to a predetermined value, and disabling the collision awareness constraint, If a support leg is to be used in the plan and the support leg is in contact with the ground, the steps include setting the target linear acceleration of the foot trajectory tracking task to a predetermined value, setting the target plantar force of the plantar force tracking task to a plantar force provided by the MPC or other module, setting the plantar force constraint to a friction cone constraint, and disabling the collision awareness constraint, A method for planning and controlling a legged robot according to claim 7, comprising the steps of: setting the target of the foot trajectory tracking task to track a speed directed toward the collision surface when the support leg is planned to be a support leg and is not in contact with the ground; setting the target plantar force of the plantar force tracking task to a preset value; setting the plantar force constraint to a preset value; and enabling the collision awareness constraint.
  9. The planning and control method for a legged robot as described in feature 1.
  10. A planning and control system for a legged robot, An acquisition module for acquiring motion commands and motion status of a legged robot, A generation module for generating a reference state sequence and next time swing parameters for each leg of the leg-type robot based on the motion command and the motion state, Based on the aforementioned motion state and the next time swing parameters for each leg, the foot end reference state of each leg is determined, and for the leg that starts swinging at the next time, a planning module is provided for planning a swing leg trajectory with collision awareness based on a foot end dynamics model and a discrete collision model, such that the effects that occur after the early collision are within the target constraint range. A planning and control device for a legged robot, comprising: a control module for whole-body control of the legged robot based on the motion state, the reference state sequence, and the foot end reference state, wherein, when a support leg is planned to be a support leg and is not in contact with the ground, collision-aware whole-body control is performed based on a whole-body dynamics model and a discrete collision model so that the effects occurring after a delayed collision are within the target constraint range.
  11. A legged robot comprising a memory, a processor, and a computer program stored in the memory and operable on the processor, wherein the processor executes the program to realize the planning and control method for the legged robot described in any one of claims 1 to 9.
  12. A computer-readable storage medium in which a computer program is stored, characterized in that the program is executed by a processor to realize the planning and control method for a legged robot described in any one of claims 1 to 9.

Description

This application relates to the field of robotics technology, and more particularly to a planning and control method, apparatus, robot, and storage medium for a legged robot. Legged robots are developing rapidly, and many are evolving beyond static walking to become faster, more sensitive, more robust, safer, and more functional. When legged robots perform high-dynamic movements, the issue of collision between their soles and the ground cannot be ignored. Related technologies allow for the adjustment of leg-based robots from both a hardware and control algorithm perspective. From a hardware standpoint, foot pads with a certain degree of flexibility may be attached to the soles of the robot's feet, or shock absorbers such as spring dampers may be attached to the robot's drive joints. Alternatively, VIA (Variable Impedance Actuators) or VSA (Variable Stiffness Actuators) can be employed to provide the desired passive mechanical impedance, achieving the effect of changing joint impedance at the mechanical level, thereby allowing the shock absorber effect to be adjusted according to actual needs. From a control algorithm perspective, the contact velocity between the sole of the foot and the ground can be brought close to zero in the motion plan. However, there are certain shortcomings in the methods of the related technologies. In terms of hardware, the introduction of materials affects the response frequency to the robot system, and since the stiffness, damping, and inertial properties of the materials are constant, the cushioning effect cannot be adjusted according to actual needs. Using VIA or VSA makes the overall structure too complex, resulting in large volume and weight, making it difficult to apply such actuators to legged robots requiring high dynamic motion. In terms of control algorithms, when legged robots perform high dynamic motion, there may be a significant error between the actual motion trajectory and the planned trajectory of the swinging leg. This can cause premature or delayed ground contact of the sole, generating enormous plantar force impacts, causing zero-position drift of the joints, and potentially accelerating hardware aging. The above and/or additional aspects and advantages of the present application will become apparent and readily apparent from the following description of the embodiments with reference to the accompanying drawings. This is a flowchart of the planning and control method for a legged robot according to the embodiment of the present invention. This is a schematic diagram of a collision-aware quadruped robot walking control system according to an embodiment of the present invention. This is a schematic diagram of a decision-making tree for whole-body control with collision awareness according to an embodiment of the present invention. This figure shows an example of a planning and control device for a legged robot according to an embodiment of the present invention. This is a schematic diagram of the structure of a legged robot according to an embodiment of the present invention. Cross-reference of related applications The embodiments of this application shown in the drawings will be described in detail below. In all drawings, the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions. The embodiments described below through the reference drawings are illustrative and for illustrative purposes only, and should not be understood as limitations thereto. In recent years, the field of legged robotics has developed rapidly, with an increasing number of mature and stable methods being applied to the motion planning and control of legged robots. Many research institutions are developing legged robots that are not limited to static walking, but are evolving in directions such as being faster, more sensitive, more robust, safer, and having more functions. When legged robots perform high-dynamic motion, problems that are negligible in low-dynamic motion become significant. For example, when legged robots run at high speeds, the problem of collision between the soles of the feet and the ground becomes a concern. Legged robot movement is achieved by the continuous switching of supporting legs, and the soles of the feet must make contact with the ground with each step. This is a deliberate collision with the environment, and a common collision problem when legged robots interact with their environment. If the collision control is inadequate, the soles of the feet may collide violently with the ground, affecting the robot's subsequent motion, causing it to lose balance, fall over, and potentially shortening or damaging the hardware lifespan. In related technologies, solutions to the legged robot collision problem can be proposed from two perspectives: hardware and control algorithms. In terms of hardware, foot pads with a certain degree of flexibility can be attached to the soles of the robot's feet, and shock abs