RU2551740C2 - Robot hand - Google Patents

Abstract

FIELD: physics, robotics.

SUBSTANCE: invention relates to robotics and can be used in designing humanlike robots. A robot hand, made in the form of a simple structure, comprises fingers, motors, tendons placed inside guide pipes and attached to the mobile housing of the motors, screws, two discs connected to each other by a pipe with grooves and between which each of the screws is rigidly attached. Radially arranged plates are rigidly attached to the housings of the motors, said plates being configured to move in said grooves and preventing the motors from turning about their own axis. The rotor of each motor is in the form of a rotating nut which is turned on the corresponding screw and determines the direction of movement of the motor thereon.

EFFECT: improved design.

3 dwg

Description

FIELD OF THE INVENTION

The invention relates to the field of robotics and can be used in the construction of humanoid robots.

State of the art

There is a wide variety of hands of the robot http://mindtrans.narod.ru/hands/hands.htm, manufactured in series for the robotics market or for research purposes. Their general construction principle is as follows. The hand is made humanoid, with movable joints of the fingers. The joints are driven by electric, pneumatic or hydraulic actuators using gear, belt, friction or cable drives. The main problem of building a hand consists in its complexity with a strict restriction on size and, as a result, in high cost, which does not allow creating a robot suitable for the consumer market.

Known hand (patent US 20130104686 A1), containing a block of hydraulic cylinders and tubes that supply fluid to them. The force from the hydraulic cylinders is transmitted to the mechanisms that drive the phalanx of the fingers of the robot. The disadvantage of this design is the complexity that can be seen from the drawings of the said patent, as well as from the price of the robot, which exceeds one million dollars (http://ru.wikipedia.org/wiki/ASIMO).

A robot arm is also known (patent US 20100011899 A1), containing a set of pulleys and cable gears driven by electric motors. The disadvantages of this device is the ability to slide the cable from the pulley and the overall complexity of the design.

A robot arm is also known (patent EP 2431139 A1), in which the movement of the fingers is transmitted using a gear system. The disadvantage of this design is the high complexity associated with the need to withstand small tolerances for gaps in gears and their mountings.

Closest to the proposed device is a finger motion control system protected by US patent US 20110071678 A1 "Tendon driven finger actuation system" and consisting of a motor connected to a gear, a gear, a linear actuator connected to the first end of the tendon located inside the guide tube. The tendon is connected by a second end to the movable nut of the linear actuator. The linear actuator is a screw with a round nut, which is protected from turning by means of a pin, which is attached to the screw and located inside a slot made in the linear actuator case. The screw is fixed in the housing using two bearings and is connected to the gearbox using a coupling. When the engine rotates, the screw rotates, and the nut moves translationally and remains stationary in the direction of rotation of the engine, transmitting movement to the tendon attached to it. The tendon transmits movement to the joints of the finger. To control the movement of all fingers, the described parts of the device are arranged in a semicircle.

The disadvantage of this device is the complexity, namely a large number of separately manufactured parts in the construction of the robot arm.

SUMMARY OF THE INVENTION

The technical result of the invention is to reduce the number of parts in the device.

The technical result is achieved by the fact that in the proposed device, the movable part is not a nut moving linearly along a screw that rotates by a fixed engine (as is done in the prototype device), but the engine itself. To implement this idea, we used a standard stepper motor with a rotor made in the form of a nut (the rotor is not shown in the figures), into which a screw is inserted. In the proposed design (Fig. 1), the screw 1 is rigidly fixed in two disks 2 and 3, and a radially located plate 7 is fixed on the motor 4 (Fig. 2), which prevents the stepper motor 4 from turning around its axis, moving into the groove 5, made in a pipe 6 rigidly connecting the disks 2 and 3 in FIG. 1. Therefore, when the rotor rotates, the motor moves along the screw. The tendon 8 (Fig. 3) is attached directly to the housing of the engine 4 and is placed in the guide tube 9 (shown by the dotted line in Fig. 3), which sets the direction of transmission of force. The number of engines 4 (Fig. 1) depends on the required number of degrees of freedom of hand.

The idea of rigidly securing the screw with a movable engine and a rotating nut made it possible to exclude the gearbox, clutch, bearing, linear actuator housing from the prototype design and simplify the method of fixing the screw. The screw 1 (Fig 1) is fixed motionless in two disks 2 and 3, which are common to all hand motors, which also simplifies the design.

List of figures and other materials

FIG. 1 is a general view of a robot arm. Here 1 is a screw; 2 and 3 - disks; 4 - engine, 6 - pipe.

FIG. 2 is an illustration of a method for preventing engine rotation around its axis. Here 3 is a disk, 4 is an engine; 5 - groove in the pipe; 6 - pipe; 7 - plate.

FIG. 3 is an illustration of the process of transferring force to the joints of a finger. Here 4 is the engine; 6 - pipe; 8 - tendon; 9 - a directing tube.

Information confirming the possibility of carrying out the invention

The invention is carried out in strict accordance with the description in the section "Summary of the invention". The screws 1 are fixed in the disks 2 and 3 (Fig. 1) using fixing screws screwed into the threads cut in the disks 2 and 3. The axis of the holes for the threads are located on the disks radially. The pipe 6 performs the function of connecting the disks 2 and 3 and at the same time serves to lay the motor power wires in it. The wires from the motors are made in the form of a spiral (spring), which covers the screw 1 and when the motor 4 moves along the screw 1 is compressed or stretched like a spring. The hand is made of soft silicone rubber. The tube 9 is inserted inside the hand during pouring the mold with silicone rubber.

The typical number of engines in the hand is six, but in the general case it can be arbitrary. Their number corresponds to the required number of degrees of freedom of the fingers.

The engines in the prototype we implemented are arranged in a circle, which ensures maximum density of the device layout.

As motors with a rotor in the form of a nut, widely used on the market are stepper motors with permanent magnets (see, for example, the 25BYZB03 motor (http://stepmotor.ru/25byz/)).

Hand work is as follows. In the initial state, the fingers are straightened and held in this state by the elastic force of the silicone rubber from which the wrist is poured. When voltage is applied to the corresponding engine (for example, engine 4 in Fig. 1), its rotor begins to rotate and wind on screw 1. At the same time, the corresponding motor begins to move along screw 1, pulling (or loosening) the tendon 8 (Fig. 3), attached to this engine. When the tendon is tensioned, the finger of the robot bends, when loosened, it bends due to the elastic strength of silicone rubber. The guide tube 9 sets the direction of the tendon tension force required to effectively control the movement of the finger.

The design of the prototype of the robot arm we have implemented is extremely simple and its cost is about 10 times lower than that of the prototype or analogues.

According to the author, the essence of the claimed invention does not follow explicitly from the prior art for a specialist, since a direct solution to the problem widely used in linear actuators (see, for example, http://fam-drive.ru/linak/actuators) consists in that the engine is fixed, a rotary screw, on which is located a nut moving along the screw, which does not rotate. In the proposed solution, the movable part is the engine itself, the nut rotates and is stationary in the direction along the screw.

A video clip confirming the possibility of carrying out the invention is available on youtube at http://www.youtube.com/watch?v=RiBAcQcEh9s.

The design of the hand is very technological and at the moment is preparing technological equipment for its serial production.

Claims (1)

A robot arm containing fingers, motors, tendons located inside the guide tubes, and screws, characterized in that it is provided with two disks interconnected by a pipe with grooves and between which each screw is rigidly fixed, while the motor bodies are rigidly attached radially arranged plates, made with the possibility of movement in the said grooves and preventing rotation of the engines around its axis, and the rotor of each of the engines is made in the form of a rotating nut, wound on a corresponding the corresponding screw, which sets the direction of movement of the engine along it, while the tendons are fixed to the movable housing of the engines.

Images