Humanoid robot lower limb system

Abstract

The invention relates to the technical field of robots, and discloses a humanoid robot lower limb system, comprising: a crotch portion comprising a rope-driven motor; the thighs are installed at the two ends of the crotch respectively and can rotate along a pitch axis and a roll axis; the shanks are installed at the lower ends of the two thighs respectively, a knee joint motor is installed on the upper portion of each thigh, and the shanks are driven to rotate relative to the thighs through the knee joint motors and the synchronous belts; the ankles are mounted at the lower ends of the two shanks respectively; the rope drive motor drives the shank opposite to the ankle to rotate through the steel wire rope. The synchronous belt has the characteristics of high transmission precision and strong anti-interference capability in a non-severe environment, the rope drive has the characteristic of high sensitivity, and all motors are intensively arranged at the uppermost end of the leg structure, so that the center of gravity is concentrated on the upper part, the inertia of leg movement is reduced, and the movement control is facilitated. Meanwhile, the principle that the left leg and the right leg are designed into blocks is adopted, so that the left leg and the right leg can rotate independently, and walking in multiple terrains is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of robot technology, and in particular to a lower limb system of a humanoid robot. Background Art

[0002] With the rapid advancement of science and technology and the increasing demand for intelligence, the research on humanoid robots has received widespread attention and in-depth exploration around the world. As a key branch in the field of robotics, humanoid robots can imitate human gait and posture and adapt to complex environmental changes, so they show great application potential in service, medical, rescue and other fields. Traditional robot designs perform well in static and structured environments, but as robots gradually move towards human daily environments, their flexibility and stability become particularly important, especially the design of the lower limb system is critical to achieving balanced walking and complex gaits of robots.

[0003] The common humanoid robot lower limb designs on the market are mainly divided into two types: motor direct drive and connecting rod transmission. Both of these can achieve basic walking functions. Although this type of design has a certain degree of stability, the motor direct drive design distributes the motors in various joints, and the center of gravity is biased downward, resulting in high inertia and slow response during movement. It is not conducive to the robot maintaining balance in uneven terrain or dynamic environments, and the gait is not flexible and adaptable enough. The connecting rod transmission type has more rotating pairs, making it difficult to control the friction of each rotating joint to be consistent, which has a greater impact on the robot's transition from a simulated environment to a real environment.

[0004] With the increasing requirements for flexibility and dynamic balance, the concept of rope-driven lower limbs began to emerge. That is, steel ropes, Bowden cables, etc. are used to transmit power to each joint, so that the lower limbs have good flexibility by simulating human muscle drive.

[0005] The patent with publication number CN118182675A discloses a humanoid robot and its lower limb device, which are mainly designed by connecting rod transmission. In the leg motor setting, the knee joint, ankle flip forward and backward, and left and right flipping are three rotating joints that adopt connecting rod transmission, and the remaining motors are directly driven. In this joint design using connecting rod transmission, each connecting rod needs at least two joint ball bearings, and there are three connecting rods in one leg. The bearings at each connecting rod are the main force points during movement. The bearings are very easy to be damaged, resulting in uneven friction, which has a great impact on control.

[0006] In the prior art, there is another common leg design, that is, all rotating joints are direct-drive designs, the motors are dispersed, and the motors are arranged throughout the legs. The weight is almost evenly distributed on the legs, which makes the center of gravity of the legs low, the inertia of movement is large, and there is a problem of slow response. At the same time, the legs cannot achieve a lightweight hollow design, resulting in a heavy structure, and the appearance is also thick and lacks aesthetics.

[0007] In summary, the existing humanoid robot leg structure is mainly connected rod driven or directly driven. Connecting rod driven has problems such as large bearing installation friction, easy bearing damage, and weak connecting rod anti-interference ability. The motor direct drive design requires the motor to be installed directly on the shaft without any intermediate transmission. Although the transmission accuracy is high, it will cause the weight of the humanoid robot's legs to be dispersed, and the center of gravity will be biased towards the center of the leg. The inertia is large during motion control, which leads to a sudden increase in the difficulty of motion control. On the other hand, the motor direct drive method installs the motor in a dispersed manner, making it difficult to design lightweight structural parts, increasing the overall leg weight, and greatly affecting the design aesthetics.

[0008] In the prior art, the problems to be solved are as follows:

[0009] (1) Reduce the impact of friction instability on overall leg control;

[0010] (2) The center of gravity of the legs is concentrated on the upper end of the legs, which moves the center of gravity upward and reduces the inertia of movement;

[0011] (3) Lightweight design to reduce overall weight;

[0012] (4) Leg flexibility issues for multiple terrains;

[0013] (5) Improvement of transmission accuracy and anti-interference issues. Summary of the invention

[0014] In order to solve the above technical problems, the present invention provides a humanoid robot lower limb system, which uses a synchronous belt and a rope drive transmission to design the leg structure of the humanoid robot. The synchronous belt has the characteristics of high transmission accuracy and strong anti-interference ability in non-harsh environments, and the rope drive has the characteristics of high sensitivity. All motors are concentrated at the top of the leg structure to concentrate the center of gravity upward, reduce the inertia of leg movement, and facilitate movement control. At the same time, the principle of block design of the left and right legs is adopted, so that the left and right legs can rotate independently, which is conducive to walking on multiple terrains.

[0015] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0016] A humanoid robot lower limb system, comprising:

[0017] crotch section, including the rope drive motor;

[0018] There are two thighs, which are installed at both ends of the crotch, and can be rotated along the pitch axis and roll axis respectively through the pitch axis motor and roll axis motor installed on the crotch;

[0019] There are two calves, which are installed at the lower ends of the two thighs respectively. A knee joint motor is installed at the upper part of each thigh. The knee joint motor and the synchronous belt drive the calf to rotate relative to the thigh.

[0020] There are two ankles, which are respectively installed at the lower ends of the two calves; the rope-driven motor drives the ankles to rotate relative to the calves through the steel wire rope.

[0021] Furthermore, the crotch portion further comprises a waist connection plate, a waist motor, a left leg hip connection plate, a right leg hip connection plate and a connection piece;

[0022] The fixed end of the waist motor is fixedly connected to the left leg hip connection plate, and the rotating end is fixedly connected to the right leg hip connection plate; the right leg hip connection plate is fixedly connected to the waist connection plate; the rope drive motor is fixedly mounted on the waist connection plate;

[0023] There are two roll shaft motors, the fixed ends of which are respectively mounted on the right leg hip connection plate and the left leg hip connection plate, and the rotating ends are respectively fixedly connected to the two connecting pieces;

[0024] There are two pitch axis motors, the fixed ends of which are respectively fixedly connected to two connecting pieces, and the rotating ends of which are respectively fixedly connected to the thighs.

[0025] Furthermore, the thigh also includes a first synchronous pulley, a second synchronous pulley, a thigh plate and a synchronous belt; the fixed end of the knee joint motor is arranged at the upper end of the thigh plate, and the rotating end is fixedly connected to the first synchronous pulley; the second synchronous pulley is rotatably installed at the lower end of the thigh plate and is fixedly connected to the calf; the synchronous belt passes around the first synchronous pulley and the second synchronous pulley.

[0026] Furthermore, the thigh also includes a tensioning wheel; the tensioning wheel is fixedly mounted on the thigh plate and is used to tighten the synchronous belt.

[0027] Furthermore, the calf includes a knee joint connector, a calf carbon tube and an ankle connector; the knee joint connector is fixedly installed on the upper end of the calf carbon tube; the ankle connector is fixedly installed on the lower end of the calf carbon tube; a bearing is provided on the ankle connector; the fixed end of the bearing is fixedly connected to the ankle connector, and the rotating end is fixedly connected to the ankle; the knee joint connector is provided with a wire rope routing groove for limiting the wire rope.

[0028] Furthermore, the ankle includes a plane bearing, ankle side panels, steel wire ropes, steel wire rope fixings, a silicone pad and an ankle base plate; the ankle side panels are symmetrically installed on both sides of the ankle base plate; the silicone pad is fixedly installed on the bottom of the ankle base plate; the plane bearing is fixedly arranged on the ankle side panels, and the rotating end of the plane bearing is fixedly connected to the lower end of the calf; the steel wire rope fixings are distributed on the front and rear sides of the plane bearing, and the steel wire ropes include a front steel wire rope located on the front side of the calf and a rear steel wire rope located on the rear side of the calf, and the lower ends of the front steel wire rope and the rear steel wire rope are respectively fixedly connected to the two steel wire rope fixings.

[0029] Compared with the prior art, the beneficial technical effects of the present invention are:

[0030] 1. The present invention adopts synchronous belt drive, has a precision close to that of direct motor drive, and has better anti-interference performance than connecting rods, and reduces the accuracy requirements for the friction force of the rotating joint.

[0031] 2. The ankle joint is driven by rope, which is lightweight, flexible and agile.

[0032] 3. The motor moves upward as a whole, and the main weight is concentrated on the upper end of the lower limbs, so that the overall center of gravity moves upward and reduces the inertia of movement.

[0033] 4. The two legs are driven by separate motors, which provide greater flexibility when moving on complex terrain.

[0034] 5. The overall lightweight design reduces the overall weight and is more conducive to motion control. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the structure of the lower limb system of a humanoid robot in an embodiment of the present invention;

[0036] Figure 2 is a schematic diagram of the crotch structure in an embodiment of the present invention;

[0037] Figure 3 is a schematic diagram of the thigh structure in an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the lower leg structure in an embodiment of the present invention;

[0039] Figure 5 Schematic diagram of the ankle structure in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] A preferred embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0041] Depend on Figure 1As shown, the humanoid robot lower limb system proposed by the present invention includes four parts: a crotch 1, a thigh 2, a calf 3 and an ankle 4. Among them, the crotch 1 has one, which is installed at the upper end of the thigh 2, the thigh 2 has two, which are symmetrically installed at the lower end of the crotch 1, the calf 3 has two, which are respectively connected to the lower end of the thigh 2, and the ankle 4 has two, which are respectively connected to the lower end of the calf 3, and are connected to the motor arranged at the upper end of the crotch 1 through a steel wire rope 41.

[0042] The overall structure of the crotch 1 is as follows Figure 2 As shown, it includes a rope drive motor 12, a waist connecting plate 11, a waist motor 17, a connecting piece 16, a pitch axis motor 15, a roll axis motor 14 and a hip connecting plate. There are two rope-driven motors 12, which are symmetrically installed on the left and right sides of the waist connecting plate 11, and are used to control the steel wire 41 of the ankle 4 for remote rope-driven control, with good flexibility; there is one waist motor 17, the rotor of the waist motor 17 is connected to the right leg hip connecting plate 13, the shell of the waist motor 17 is connected to the left leg connecting plate, and the right leg hip connecting plate 13 is fixedly connected to the waist connecting plate 11, when the waist motor 17 rotates, the right leg will rotate alone, so that the single foot can rotate independently to maintain flexibility; there are two roll shaft motors 14, which are installed on the back of the right leg hip connecting plate 13 and the left leg hip connecting plate 18, and the rotor of the roll shaft motor 14 is respectively connected to two connecting parts 16; the two connecting parts 16 are respectively connected to the shell of a pitch shaft motor 15, and the rotor of the pitch shaft motor 15 is used to connect with the thigh 2 to control the lifting and lowering action of the thigh 2.

[0043] The overall frame of the thigh 2 of the present invention is as follows Figure 3As shown, the whole lower limb includes two thighs 2, which are divided into a left thigh and a right thigh. Its structure includes a knee joint motor 21, a first synchronous pulley 22, a second synchronous pulley 30, a first inner cover 23, a second inner cover 24, a first tensioning wheel 25, a second tensioning wheel 26, an outer cover 27, a thigh plate 28 and a synchronous belt 29. The knee joint motor 21 is arranged at the upper end of the thigh 2, and is installed concentrically with the upper end through hole of the thigh plate 28, exposing the rotor; the knee joint motor 21 is connected to the first synchronous pulley 22 by screws, that is, the motor is directly driven; the first tensioning wheel 25 is arranged at the mounting hole on the upper inner side of the thigh plate 28, and the second tensioning wheel 26 is arranged at the mounting hole below the first tensioning wheel 25 on the inner side of the thigh plate 28. Both tensioning wheels are connected by a central axis, can rotate smoothly, and play the role of tightening the synchronous belt 29; the second synchronous pulley 30 is installed at the mounting hole at the lower inner side of the thigh plate 28, connected by the central axis, and used to be connected to the calf 3 by screws; the synchronous belt 29 bypasses The first synchronous pulley 22, the second synchronous pulley 30, the first tensioning pulley 25 and the second tensioning pulley 26 are installed. When the knee joint motor 21 rotates, the first synchronous pulley 22 is driven to rotate, thereby transmitting the power to the second synchronous pulley 30. The second synchronous pulley 30 is connected to the calf 3, so the calf 3 can rotate, realizing the transmission process of the synchronous belt 29; the first inner cover 23 is installed on the inner side of the uppermost end of the thigh plate 28 by screws; the second inner cover 24 is installed on the inner side of the thigh plate 28 by screws, covering the synchronous belt 29, the synchronous belt 29 wheel, the tensioning pulley and other components to prevent damage to the transmission components; the outer cover 27 is installed on the outer side of the thigh plate 28 by screws for decoration.

[0044] The overall structure of the lower leg 3 of the present invention is as follows Figure 4 As shown, the entire lower limb includes two, which are divided into the left calf and the right calf. The overall lightweight design includes three parts: a knee joint connector 31, a calf carbon tube 33, and an ankle connector 34. The knee joint connector 31 is installed at the upper end of the calf carbon tube 33 and connected by screws; the ankle connector 34 is installed at the lower end of the calf carbon tube 33 and is also connected by screws, and a bearing 35 is installed at the center of the ankle connector 34 for the rotation of the ankle 4. Two wire rope routing grooves 32 are set on the knee joint connector 31, which are symmetrically arranged front and back, and are used to limit the wire rope 41 of the ankle 4.

[0045] The ankle 4 overall frame of the present invention is as follows Figure 5As shown, the entire lower limb includes two, namely the left foot and the right foot, each of which includes a plane bearing 46, a steel wire rope 41, an ankle side plate 45, a steel wire rope fixing part 43, a silicone pad 42 and an ankle bottom plate 44. Among them, there are two ankle side panels 45, which are symmetrically installed on both sides of the ankle base plate 44 and have a mortise and tenon structure to ensure its stability; there are two silicone pads 42, which are installed at the bottom of the ankle base plate 44 by screws, and are installed symmetrically front and back to play an anti-slip and buffering role; the plane bearing 46 is installed at the through hole at the upper end of the ankle side panel 45, and the through hole is connected to the bearing on the ankle connector 34 in the calf 3 by an axle pin. The plane bearing 46 is used to solve the friction between the ankle connector 34 and the ankle side panel 45 to maintain its smooth rotation; there are two wire rope fixing parts 43, which are installed at the upper end of the ankle base plate 44, installed front and back, and connected to the two ankle side panels 45 with screws; the center holes of the two wire rope fixing parts 43 are respectively connected to a wire rope 41, and the wire rope 41 passes through the wire rope routing groove 32 of the knee joint connector 31 of the calf 3, and then is connected to the rope drive motor 12 of the crotch 1, and the rotation of the rope drive motor 12 drives the ankle 4 to rotate forward and backward. When the rope drive motor rotates forward, the steel wire rope 41 at the front end of the ankle 4 is loosened, the steel wire rope 41 at the rear end is tightened, and the ankle 4 rotates forward; when the rope drive motor 12 rotates reversely, the steel wire rope 41 at the front end of the ankle 4 is tightened, the steel wire rope 41 at the rear end is loosened, and the ankle 4 rotates backward.

[0046] The lower limb system of the humanoid robot in the present invention is divided into four modules, namely, a crotch 1, a thigh 2, a calf 3, and an ankle 4, which can be connected in a modular manner, thereby improving the stability of the structure.

[0047] The present invention adopts the synchronous belt 29 and the rope drive mode to carry out joint transmission, has the accuracy close to the direct drive, and has certain anti-interference performance, is more flexible and agile, and has good anti-interference performance.

[0048] In the present invention, the motors are arranged at the uppermost ends of the lower limbs, so that the center of gravity moves upward and the movement inertia is reduced.

[0049] The two legs of the present invention are driven independently, which improves the adaptability to terrain and is beneficial to walking on various terrains.

[0050] The overall lightweight design of the present invention reduces the weight of the entire machine, which is beneficial to the development and use of humanoid robots.

[0051] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0052] In addition, it should be understood that although the present specification is described in terms of implementation modes, not every implementation mode contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A humanoid robot lower limb system, characterized in that: include: crotch section, including the rope drive motor; There are two thighs, which are installed at both ends of the crotch, and can be rotated along the pitch axis and roll axis respectively through the pitch axis motor and roll axis motor installed on the crotch; There are two calves, which are installed at the lower ends of the two thighs respectively. A knee joint motor is installed at the upper part of each thigh. The knee joint motor and the synchronous belt drive the calf to rotate relative to the thigh. There are two ankles, which are respectively installed at the lower ends of the two calves; the rope-driven motor drives the ankles to rotate relative to the calves through the steel wire rope.

2. The humanoid robot lower limb system according to claim 1, characterized in that: The crotch portion further comprises a waist connection plate, a waist motor, a left leg hip connection plate, a right leg hip connection plate and a connection piece; The fixed end of the waist motor is fixedly connected to the left leg hip connection plate, and the rotating end is fixedly connected to the right leg hip connection plate; the right leg hip connection plate is fixedly connected to the waist connection plate; the rope drive motor is fixedly mounted on the waist connection plate; There are two roll shaft motors, the fixed ends of which are respectively mounted on the right leg hip connection plate and the left leg hip connection plate, and the rotating ends are respectively fixedly connected to the two connecting pieces; There are two pitch axis motors, the fixed ends of which are respectively fixedly connected to two connecting pieces, and the rotating ends of which are respectively fixedly connected to the thighs.

3. The humanoid robot lower limb system according to claim 1, characterized in that: The thigh also includes a first synchronous pulley, a second synchronous pulley, a thigh plate and a synchronous belt; the fixed end of the knee joint motor is arranged at the upper end of the thigh plate, and the rotating end is fixedly connected to the first synchronous pulley; the second synchronous pulley is rotatably installed at the lower end of the thigh plate and is fixedly connected to the calf; the synchronous belt passes around the first synchronous pulley and the second synchronous pulley.

4. The humanoid robot lower limb system according to claim 3, characterized in that: The thigh also includes a tensioning wheel; the tensioning wheel is fixedly installed on the thigh plate and is used to tighten the synchronous belt.

5. The humanoid robot lower limb system according to claim 1, characterized in that: The calf includes a knee joint connector, a calf carbon tube and an ankle connector; the knee joint connector is fixedly installed on the upper end of the calf carbon tube; the ankle connector is fixedly installed on the lower end of the calf carbon tube; a bearing is provided on the ankle connector; the fixed end of the bearing is fixedly connected to the ankle connector, and the rotating end is fixedly connected to the ankle; the knee joint connector is provided with a wire rope routing groove for limiting the wire rope.

6. The humanoid robot lower limb system according to claim 1, characterized in that: The ankle includes a plane bearing, ankle side panels, steel wire ropes, steel wire rope fixings, a silicone pad and an ankle bottom plate; the ankle side panels are symmetrically installed on both sides of the ankle bottom plate; the silicone pad is fixedly installed on the bottom of the ankle bottom plate; the plane bearing is fixedly arranged on the ankle side panels, and the rotating end of the plane bearing is fixedly connected to the lower end of the calf; the steel wire rope fixings are distributed on the front and rear sides of the plane bearing, and the steel wire ropes include a front steel wire rope located on the front side of the calf and a rear steel wire rope located on the rear side of the calf, and the lower ends of the front steel wire rope and the rear steel wire rope are fixedly connected to the two steel wire rope fixings respectively.

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