CN102814818B - Multi-finger anthropomorphic hand for robot - Google Patents

Abstract

The invention discloses a multi-fingered humanoid hand for a robot, which includes a wrist, a palm, and a plurality of fingers connected to the palm, each finger has a plurality of joints, and also includes a plurality of springs, which are respectively arranged on the plurality of fingers Each joint of the , provides the moment that holds the fingers in extension. The multi-fingered anthropomorphic hand uses springs with different elastic coefficients on the same finger to make the joints of the fingers bend at different angles when grasping, so that it is more similar to a human hand; It has a certain degree of curvature and flexibility when grasping, which can increase the stability of grasping.

Description

A multi-fingered humanoid hand for a robot

technical field

The invention relates to a multi-fingered humanoid hand for a robot. The hand has an elastic palm and is suitable for the multi-fingered hand of a humanoid robot to achieve the effect of anthropomorphic hands.

Background technique

With the development of industrialization, human production activities have gradually penetrated into some special fields, such as inspection and maintenance of equipment in environments such as underwater, underground, nuclear radiation, and space stations; precise operations on some large objects, such as automobiles Assembly; medical minimally invasive surgery, etc. These jobs are either dangerous or difficult to complete, and it is very necessary for robots to replace humans to complete these jobs.

These complex tasks require that the robot's hand device has the ability to complete fine manipulations, and at the same time, it can quickly adapt to the grasping of objects with complex geometries through finger movements. However, most of the robots in practical applications today use simple end effectors to clamp the workpiece to complete the work, which has the disadvantages of lack of flexibility, limited clamping methods, low efficiency, and high energy consumption. Multi-fingered dexterous hands help to solve the above problems, making robots more flexible and versatile. Due to its adaptability, the multi-fingered dexterous hand can realize a variety of different gripping without changing the end effector.

Judging from the research progress of robotic grippers, multi-fingered dexterous hands are still the most researched. The transmission mode of the fully-driven multi-fingered dexterous hand based on tendons and pulleys (or hoses) results in small output, poor load capacity, and complicated control, which restricts its application in robots. The underactuated finger realizes the passive self-adaptation of the unpowered joint to the grasped shape through the underactuated finger mechanism, mechanical limit and spring. It has the characteristics of less driving components, wide grasping range, simple control, large output force and good load capacity. . However, the elastic elements in the underactuated mechanism have caused certain difficulties to the precise control of the underactuated hand, such as precise trajectory tracking, force control, etc., especially some domestic underactuated hands, coupled with the limitation of the number of sensors, It is difficult to achieve complex and accurate operations, limiting its dexterity. In addition, since the palm of the existing humanoid hand is mostly composed of steel plates, which has poor elasticity, when the grasping operation is completed, there are few contact points and small contact area between the palm and the grasped object, and the grasping is unstable.

After a long period of evolution, human hands are very flexible, not only can make various gestures, but also can complete operations such as lifting heavy objects. Each hand is composed of 29 bones as a scaffold, these bones are connected by 123 ligaments, and pulled by 35 strong muscles. Therefore, when the human hand grabs objects and makes various gestures, the movements are very soft and reliable. When the human hand grabs an object, not only the joints of the fingers can be in contact with the object, but the palm also has a large area to be in contact with the object. In this way, the grasping is relatively stable, and the object is not easy to slip. However, the existing robot hands are very stiff and uncoordinated when making gestures; the palm is made of rigid materials, and there are fewer contact points between the palm and the object when grasping the object, so there is little friction with the object , easy to slip off.

Therefore, it is necessary to enable the robot multi-fingered hand to achieve precise control of the hand and enhance the stability of the multi-fingered hand under the premise of using fewer driving elements to obtain sufficient force.

Contents of the invention

In view of the above-mentioned defects of the prior art, embodiments of the present invention provide a robotic multi-fingered hand with elastic palm and more natural finger bending, so as to solve the problems of the prior art. The multi-fingered hand can have a strong load-carrying capacity and can perform relatively precise control on the premise of using fewer driving elements. When the dexterous hand completes the grasping task, the elastic palm can be bent, increasing the force contact points between the hand and the object, increasing the contact area, and making the grasping more stable. When the multi-fingered hand performs tasks such as screwing, it can well control the movement accuracy of the hand; when the multi-fingered hand holds an object, it can grasp it firmly without slipping.

A multi-fingered humanoid hand for a robot, comprising a wrist, a palm, and multiple fingers connected to the palm, each finger having multiple joints, characterized in that it also includes

A plurality of springs, which are respectively arranged on each joint of the plurality of fingers, provide moment to keep the fingers in an extended state;

The driving device, which is placed inside the anthropomorphic hand, can provide a driving force for each of the plurality of fingers, and the driving force makes the joints of the fingers overcome the torque action of the springs, respectively around the axis of each joint Rotate, thereby transforming into a clenched state;

Wherein, in each of the plurality of fingers, according to the direction from the palm end to the finger end, the elastic coefficients of the springs of the joints gradually increase, so that the fingers can be bent to complete the grasping action.

Preferably, the plurality of fingers includes the index finger, and the index finger has a palmar joint, a middle phalanx and a proximal joint, wherein the spring coefficient of the proximal joint is the smallest, and the spring coefficient of the proximal joint is the largest.

Preferably, the plurality of fingers includes a thumb, and the thumb has a proximal palm joint and a proximal finger joint, wherein the spring of the proximal palm joint of the thumb has a smaller spring coefficient, and the proximal finger joint of the thumb The elastic constant of the spring is relatively large.

Preferably, the palm includes a plurality of springs with a large elastic coefficient, so that when the grasping action is performed, the palm bends slightly, and the bending degree is adapted to the grasping action of the fingers.

Preferably, the plurality of springs are tension springs, torsion springs or bending springs.

The beneficial effect of the present invention is that under the premise of ensuring a large grasping force, the bending of the fingers is more similar to that of a human hand, so that the palm of the humanoid polyfingered hand has elasticity and the grasping is more stable; The spring with a certain coefficient makes the joints of the fingers bend at different angles when grasping, so that it is more similar to the human hand; and the palm with the spring as the main body can have a certain degree of bending and flexibility when grasping, which can increase the grip. take the stability.

Description of drawings

Fig. 1 is a multi-fingered anthropomorphic hand according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of the structure of the thumb of the multi-fingered humanoid hand in the above embodiment.

Fig. 3 is a schematic diagram of the composition of the palm of the multi-fingered humanoid hand in the above embodiment.

The meanings of the marks in the figure are as follows:

1 The proximal joint of the index finger 2 The middle knuckle of the index finger 3 The proximal joint of the index finger

4 proximal joint of thumb 5 proximal joint of thumb 6 fingers

7 Palm 8 Wrist

Detailed ways

Fig. 1 shows a multi-fingered anthropomorphic hand according to an embodiment of the present invention. The anthropomorphic hand includes a palm 7 and a wrist 8, and a plurality of fingers 6 are connected to the palm 7, and each finger has a plurality of joints. Each joint of the finger is provided with a spring to provide a moment to keep the finger in an extended state. The interior of the multi-fingered hand is provided with a driving device for each finger, which is used to drive the actions of each finger. When the driving device is driven, the driving force makes the joints of the fingers overcome the torque action of the springs, and rotate around the axes of each joint respectively, thereby transforming into a clenched state. By adjusting the elastic coefficients of the springs of the joints of each finger, the fingers can be bent to complete a predetermined grasping action.

For example, the index finger has a proximal knuckle, a middle knuckle, and a proximal knuckle. Among them, the spring elastic coefficient of the proximal palm joint 3 of the index finger is the smallest (k3), the spring elastic coefficient of the middle phalanx 2 is relatively large (k2), and the spring elastic coefficient of the proximal finger joint 1 is the largest (k1). The elastic coefficients of the three springs are in an arithmetic sequence relationship: k1=k2+k0=k2+2*k0 (k0 is a constant).

Since the driving force of each joint of the same finger is the same, when driving, the rotation angle of the proximal joint 1 of the index finger is the smallest, the rotation angle of the middle phalanx 2 is small, and the rotation angle of the proximal joint 3 is the largest. Because the spring elastic coefficients of the three knuckles are in an arithmetic sequence, the rotation angles of the three joints of the same finger are also in an arithmetic sequence: θ ₃ = θ ₂ + θ ₀ = θ ₁ + 2θ ₀ (θ ₀ is constant).

Except for the thumb, the other three fingers are similar to the index finger.

Fig. 2 shows the composition of the thumb of the multi-fingered anthropomorphic hand in the above embodiment. The thumb has proximal palmar joints and proximal finger joints. The elastic coefficient of the joint spring near the palm end of the thumb is small (k3), and the elastic coefficient of the joint spring near the finger end is large (k2). Therefore, when driving, the rotation angle of the proximal palm joint 5 of the thumb is relatively large, and the rotation angle of the proximal joint 4 of the thumb is relatively small. The relationship between the spring constant and the rotation angle is similar to that in Figure 2

Fig. 3 shows the composition of the palm of the multi-fingered humanoid hand in the above embodiment. The palm 7 is mainly composed of a plurality of springs with a large elastic coefficient. So that when the palm grasps the envelope, the spring bends slightly, and its degree of bending adapts to the grasping action of the fingers, thereby increasing the number of contact points between the palm and the object, increasing the contact area, and making the envelope grasp Take more stable, to achieve the design effect.

In addition, in addition to the embodiments using tension springs shown in the above figures, torsion springs or bending springs can also be used to provide torque for each joint to obtain alternative implementations.

The above descriptions are only several specific embodiments of the present invention, and the above embodiments are only used to illustrate the technical solutions and inventive concepts of the present invention and not limit the scope of the claims of the present invention. All other technical solutions that can be obtained by those skilled in the art on the basis of the inventive concept of this patent combined with the existing technology through logical analysis, reasoning or limited experiments should also be considered to fall within the scope of protection of the claims of the present invention .

Claims (4)

1. a Multi-finger anthropomorphic hand for robot, comprises wrist, palm, and is connected to the multiple fingers on palm, and each finger has multiple joint, it is characterized in that, also comprises

Multiple spring, it is arranged at each joint of described multiple finger respectively, provides moment finger being remained on extended configuration;

Drive unit, it is inner that it is placed in described anthropomorphic hand, and each that can be respectively described multiple finger provides driving force, and described driving force makes the joint of finger overcome the moment loading of described spring, axle respectively around each joint rotates, thus changes the state of holding with a firm grip into;

Wherein, described multiple finger each in, according to from palm end to the direction of finger tip, the coefficient of elasticity of the spring in each joint increases gradually, thus enables finger bend grasping movement;

Described multiple finger comprises forefinger, described forefinger has nearly palm end joint, middle finger joint and nearly finger tip joint, wherein the elastic coefficient k3 in nearly palm end joint is minimum, the elastic coefficient k2 of middle finger joint is larger, the elastic coefficient k1 in nearly finger tip joint is maximum, and the coefficient of elasticity of three springs is the relation of arithmetic progression;

When driving, the rotational angle in forefinger nearly finger tip joint is minimum, and middle finger joint rotational angle is less, and the rotational angle in nearly palm end joint is maximum, and the rotational angle size in three joints is arithmetic progression.

2. according to claim 1ly refer to anthropomorphic hand more, it is characterized in that, described multiple finger comprises thumb, described thumb has nearly palm end joint and nearly finger tip joint, the coefficient of elasticity of the nearly palm end joint spring of wherein said thumb is less, and the coefficient of elasticity of the nearly finger tip joint spring of described thumb is larger.

3. according to the anthropomorphic hand of many fingers one of claim 1-2 Suo Shu, it is characterized in that, described palm comprises the very large spring of multiple coefficient of elasticity, and to make when carrying out grasping movement, described palm is slightly bending, and the grasping movement of its degree of crook and finger adapts.

4. according to the anthropomorphic hand of many fingers one of claim 1-2 Suo Shu, it is characterized in that, described multiple spring is extension spring, torsionspring or flexural spring.