US-12617104-B2 - Self-adaptive mechanical foot for legged robot and working method thereof

US12617104B2US 12617104 B2US12617104 B2US 12617104B2US-12617104-B2

Abstract

The present disclosure discloses a self-adaptive mechanical foot for the legged robot. The mechanical foot has a piston disposed inside a piston cylinder. The piston is connected to one end of each humeral plate, and the piston cylinder is connected to the other end of each humeral plate. The humeral plates perform opening and closing movement through the up-down movement of the piston in the piston cylinder. The humeral plates are connected to toes on the foot and drive the toes to open and close through the up-down movement. The mechanical foot provided by the present disclosure has higher standing stability and fast interaction response speed when interacting with the terrain. It can realize arbitrary and fast switching between a point-like foot and a planar foot, and meanwhile avoids collision between a support leg and a swing leg.

Inventors

Guoteng Zhang
Xianwu Zeng
Yibin Li
Xuewen Rong
Xin Ma
Rui Song
Xincheng TIAN

Assignees

SHANDONG UNIVERSITY

Dates

Publication Date: 20260505
Application Date: 20220915
Priority Date: 20210930

Claims (5)

1 . A mechanical foot of a legged robot, comprising: a piston, disposed in a piston cylinder; a plurality of humeral plates; a plurality of toes; wherein, a first end of each of the humeral plates is connected to the piston cylinder through a proximal digital joint hinge, a second end of the each of the humeral plates is connected to a first end of a corresponding one of the toes through a digital joint hinge, and a second end of each of the toes is connected to the piston through a metacarpal joint hinge; wherein, the humeral plates perform opening and closing movements through up and down movements of the piston in the piston cylinder; and the toes perform up-down opening and closing movements through the opening and closing movements by driving by the humeral plates; a plurality of limiting blocks, being configured to move with the piston and prevent the humeral plates from engaging an outer surface of the piston cylinder, and form force singularity when the mechanical foot falls such that the toes cannot be opened; and a toe center part, being arranged at a bottom of the piston; wherein, when the mechanical foot contacts the ground, one of the toes being inclined to a leg of the legged robot and contacting the ground before others of the toes of the mechanical foot is defined as a first toe.
2 . The mechanical foot of the legged robot according to claim 1 , wherein a spring is disposed in the piston, to play a role in resetting and buffering.
3 . The mechanical foot of the legged robot according to claim 1 , wherein an outer surface of each of the plurality of limiting blocks is parallel to the corresponding humeral plate having the minimum angle with the piston cylinder.
4 . A working method of the mechanical foot of the legged robot according to claim 1 , comprising: enabling the piston to move up and down in the piston cylinder, and driving the humeral plates to perform the opening and closing movements and the toes to perform the up-down opening and closing movements; when the mechanical foot contacts the ground, the toe center part being affected by the gravity of the legged robot such that the piston moves along an interior of the piston cylinder; and when the toes are opened during extension of the humeral plates, the plurality of the toes forming a plane to jointly support the legged robot.
5 . The working method of the mechanical foot of the legged robot according to claim 4 , wherein when the mechanical foot leaves the ground, since the toe center part is not supported by the ground, the piston moves away from the piston cylinder under an effect of a spring and the gravity, and the toes contract upwards by a pulling force of the humeral plates.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 2021111589132, filed on 30 Sep. 2021 with the Chinese Patent Office, the disclosure of which are hereby incorporated by reference herein in its entirety. TECHNICAL FIELD The present disclosure relates to the technical field of robots, and in particular relates to a self-adaptive legged robot mechanical foot and a working method thereof. BACKGROUND The description in this section merely provides background information related to the present disclosure and does not necessarily constitute the prior art. With the rapid development of legged robots, mechanical ankle joints play an important role in high-performance legged robots. When the robot walks fast, the ankle joints play a small role. At the moment, we hope that the robot has point-like feet, because pure dynamic walking can achieve relatively good maneuverability. However, when the robot stops, we hope that foot ends of the robot are planar, which provide multiple supports for stable standing of the robot. According to traditional methods, using active ankle joints needs to quickly detect the contact condition of the foot ends and switch the shape change of the foot ends. That is to say, the interaction of the active ankle joints with ground environment requires the robot to respond quickly, which poses a great challenge to control algorithms, driving and sensors. At the same time, if a plane is used as the foot ends of the robot, since the foot ends occupy a relatively large space while the robot is walking, collision between a support leg and a swing leg occurs easily, causing the robot to lose stability and fall to the ground. That is, the current robot ankle joints have many problems and need to be improved. The inventor has found that the prior art at least has the following problems: a. the interaction response speed with terrain is slow;b. current passive ankle joints cannot realize arbitrary and fast switching between the point-like foot and the planar foot; andc. increasing the area of the foot ends is easy to cause collision between the support leg and the swing leg. SUMMARY In order to solve the above-mentioned problems, the present disclosure provides a self-adaptive legged robot mechanical foot and a working method thereof, which can achieve arbitrary and fact switching between a point-like foot and a planar foot. In order to realize the above objectives, the present disclosure adopts the technical solutions as follows: In a first aspect, the present disclosure provides a self-adaptive legged robot mechanical foot, including the following: A piston is disposed in a piston cylinder. The piston is connected to one end of each humeral plate. The piston cylinder is connected to the other end of each humeral plate. The humeral plates perform opening and closing movement through up-down movement of the piston in the piston cylinder. The humeral plates are connected to toes. The humeral plates drive the toes to perform up-down opening and closing movement through the opening and closing movement. Further, a spring is disposed in the piston to play a role in buffering, and the stiffness coefficient of the spring can be changed to adapt to different response speeds and buffer intensity. Further, further included are limiting blocks, disposed on the outer side of the piston cylinder, for preventing the toes and the humeral plates from being attached to the piston or the piston cylinder, and forming force singularity when the foot falls such that the toes cannot be opened normally. Further, the outer surface of each limiting block is parallel to the corresponding humeral plate having the minimum angle with the piston cylinder. Further, when the robot mechanical foot contacts the ground, the toe inclined to a leg-foot of the robot and contacting the ground before other toes of the mechanical foot is a first toe, the first toe forms a correcting effect on the legged robot. Further, the correcting intensity of the first toe to the legged robot is adjusted by changing the elasticity of the material of the humeral plates. Further, the outer layer of the mechanical foot is packaged with an integral elastic film, for preventing gravel and dust from entering a hinge part. Further, the toe number of the mechanical foot is adjustable, the toe length of the mechanical foot is adjustable, and the angles between the toes and the piston are adjustable. In a second aspect, the present disclosure provides a working method of a self-adaptive legged robot foot, including: According to the contact condition between a foot end and the ground, a piston can move up and down in a piston cylinder to drive humeral plates to perform opening and closing movement and toes to perform up-down movement. When the mechanical foot contacts the ground, a toe center is affected by the gravity of a robot such that the piston moves to the interior of the piston cylinder. When the toe