CN102501246B - Three-drive extensible dexterous mechanical arm - Google Patents

Abstract

A three-drive expandable dexterous manipulator aims to simplify the structure of the manipulator, increase the degree of freedom, and capture space targets smartly and effectively. The power source of the three-drive expandable smart robot arm is three drive units installed on the base, two of which drive the control of the three-drive expandable smart robot through the motion transmission of the screw, screw nut, push rod and connecting rod The attitude of the arm; the third drive unit controls the overall rotational motion of the three-driver expandable dexterous manipulator, so that three drive units can be used to control 2N+5 (N is a natural number) degrees of freedom. The joints of the three-drive expandable dexterous manipulator are a combination of cross shafts, joint housings, and concave-convex limit mechanisms. The joints can be bent and rotated, and the joints can be extended in series, making the manipulator with a high degree of freedom and dexterity.

Description

Three-drive expandable robotic arm

technical field

The invention relates to the technical field of robot mechanism design, specifically, a three-drive expandable mechanical arm is designed for flexible grasping and capturing of space objects.

Background technique

With the continuous deepening of space exploration, space manipulators play a vital role in engineering fields such as space docking, on-orbit service, cargo handling, and target acquisition. Facing the complex space environment, a wide variety of operating objects, and increasingly complex operating tasks, the space manipulator is required to have the characteristics of high reliability, economy, safety, and dexterity.

At present, most space manipulators have six degrees of freedom, and each joint must be equipped with a drive unit composed of a motor and a reducer. This increases the structural complexity of the space manipulator and increases the mass and moment of inertia of the space manipulator. Not conducive to saving energy. In order to improve the dexterity of the space manipulator while saving energy, it is of great significance to design a space manipulator with the characteristics of compact structure, light weight, small moment of inertia, more degrees of freedom, and less drive.

Contents of the invention

The invention proposes a three-drive expandable robotic arm, which has the characteristics of fewer drive units, high degrees of freedom, and high dexterity, and can be used in engineering fields such as space docking, on-orbit service, cargo handling, and target capture.

Technical scheme of the present invention is as follows:

A three-drive expandable mechanical arm, including a drive unit, a lead screw, a lead screw nut and a push rod, a connecting rod, a yaw ring, a joint, a ring and an end effector interface, characterized in that:

The drive unit is a combination of a rotary motor and a harmonic reducer, installed on the base of the three-drive expandable mechanical arm, and the lead screw is connected to the output shaft of the drive unit through a coupling to drive the lead screw nut Do reciprocating linear motion, the lead screw nut drives the push rod to do reciprocating linear motion, the push rod is hinged with one end of the connecting rod, the other end of the connecting rod is hinged with the outer wall of the yaw ring, the joints are cross shafts, joint shells and concave-convex limiters A combination of mechanisms, the circular ring has a diameter shaft, the circular ring and the joint shell are connected by pins, and the end effector interface is flange type, which can be connected with different types of end effectors.

Furthermore, the three-drive expandable robotic arm includes three drive units in total, two of which are connected to the lead screw through a coupling, and are sequentially transmitted through the force of the lead screw nut, connecting rod and push rod to realize the rotation of the yaw ring. Up and down and left and right yaw movements, the third drive unit is connected to the input end of the first joint through a coupling to realize the overall rotation of the three-drive expandable mechanical arm around its own axis.

Further, the lead screw drives the push rod to perform reciprocating linear motion through the lead screw nut, and the push rod is hinged to the outer wall of the deflection ring through the connecting rod.

Furthermore, the joint structure is scalable, the output end of the previous joint is also the input end of the latter joint, and the number of joints in the three-drive scalable manipulator structure can be expanded to N, where N is a natural number; the joint The concave-convex limiting mechanism has the function of omnidirectional rotation of the spherical hinge, and at the same time is limited by the concave-convex structure, which plays a role in positioning and guiding during the movement of the three-drive expandable mechanical arm.

Furthermore, the cross shaft of the previous joint is connected to the cross shaft of the subsequent joint through the joint shell, and the deflection ring is deflected under the action of the push-pull force generated by the push rod, which drives the deflection of the cross shaft in the first joint, The cross shaft in the first joint will drive the cross shaft in the second joint to deflect through the joint shell between the first and second joints, and the concave-convex limit mechanism in the first joint will serve as the fulcrum for the deflection of the second joint and limit; the subsequent motion transmission principle is the same as the above-mentioned principle, through the accumulation of the yaw motion of multiple joints, the three-drive expandable robotic arm can achieve a wide range of yaw motion.

The three-drive expandable mechanical arm designed by the present invention includes three drive units installed on the machine base, two lead screws and their lead screw nuts, push rods, connecting rods, joints and rings, and the ends have flanged The end effector interface can be connected to different end effectors according to the task requirements.

The three driving units are the power source of the three-drive expandable robotic arm. The screw and the screw nut convert the rotational motion of the motor into the reciprocating linear motion of the push rod; two of the driving units drive the screw and the nut to move, and through linkage with the nut The push rod and connecting rod act on the yaw ring to change the posture of the first joint, and transmit the force to the second joint through the cross axis and the shell force between the first joint and the second joint, and then pass it to it The connected cross shaft and the joint shell continue to change the yaw direction of the subsequent joints, and so on, to achieve the purpose of controlling the bending and yaw posture of the three-drive expandable manipulator up and down; the third drive unit drives the three-drive expandable manipulator The input end of the first joint rotates, and the rotational motion is sequentially transmitted through the joints to the end, so as to achieve the purpose of the overall rotation of the three-drive expandable robotic arm.

The joint is a combination of the cross shaft, the joint shell and the concave-convex limit mechanism. The joint shell can swing up and down around the cross axis. It is a limit mechanism with the function of a spherical hinge that is concave-convex. The two components that are concave-convex with each other can deflect in any direction, but when they deflect relative to a certain angle, due to the existence of the mechanical limit, the deflection will stop to achieve control deflection. The purpose of pendulum angle size.

The advantages of the present invention are:

1. The number of driving units of the three-drive expandable robotic arm is small, the structure is compact, and the overall weight is light;

2. The number of drive units is far less than the number of degrees of freedom of the three-drive expandable robotic arm, which has high dexterity;

3. The three-drive expandable robotic arm has strong scalability, and the number of joints can be freely adjusted according to actual task requirements.

Description of drawings

Figure 1 is a front view of the overall structure of a three-drive expandable robotic arm designed with N=2 as an example;

Figure 2 is a top view of the overall structure of a three-drive expandable robotic arm designed with N=2 as an example;

Fig. 3 is a schematic diagram of cooperation between the yaw ring, the bearing and the shell of the first joint;

Fig. 4 is a schematic diagram of the first joint shell;

Fig. 5 is a schematic diagram of the cross axis;

Fig. 6 is a schematic diagram of the casing between the first joint and the second joint;

Fig. 7 is a schematic diagram of the shell of the second joint of the three-drive expandable robotic arm;

Fig. 8 is a schematic diagram of cooperation between the first joint and the second joint;

Figure 9 is a schematic diagram of a ring;

Fig. 10 is a schematic diagram of the coordination of the second joint shell, the ring, the actuator interface and the gripper of the three-drive expandable manipulator;

Figure 11 is a schematic diagram of the bending of the three-drive expandable manipulator after the deflection ring in front view 1 is combined with two thrusts;

Figure 12 is a schematic diagram of the bending of the three-drive expandable mechanical arm after the deflection ring in the front view 1 is subjected to the joint action of two tension forces;

Fig. 13 is a schematic diagram of bending of the three-drive expandable manipulator after the deflection ring in top view 2 is combined with a push force and a pull force;

Fig. 14 is a schematic diagram of the bending of the three-drive expandable mechanical arm after the deflection ring in top view 2 is combined with a pulling force and a pushing force;

Marks in the figure: drive unit 1, 33, 34, coupling 2, 29, 32, lead screw 3, 31, lead screw nut 4, 30, push rod 5, 28, first joint input end 6, hinge 7, 9, 25, 27, connecting rods 8, 26, yaw ring 10, bearing 11, first joint housing 12, cross shafts 13, 15, first joint and second joint housing 14, second joint housing 16, pin 17 , the end effector interface 18, the claw 19, the ring 20, the concave-convex limit mechanism 21, 22, 23, and the fixing seat 24.

Detailed ways

The structure of the mechanical arm will be further described below in conjunction with the accompanying drawings.

As shown in Figures 1 and 2, three driving units 1, 33, 34 provide power for the entire mechanical arm, wherein the output ends of the driving units 1, 34 are respectively connected to the lead screws 3, 31 through couplings 2, 32; Lead screw nuts 4, 30 are respectively installed on the leading screws 3, 31, and the leading screw nuts 4, 30 are respectively connected with the push rods 5, 28, which can push the push rods to do reciprocating linear motion; there are hinges 7, 27 at the ends of the push rods, It is connected with the outer wall of the deflection ring 10 through connecting rods 8 and 26 . Through the sliding of the lead screw nuts 4 and 30, the push rods 5 and 28 are pushed respectively, and the force transmission of the connecting rods 8 and 26 can control the deflection of the deflection ring 10; the output end of the drive unit 33 is connected to the The first joint input end 6 is connected to drive the first joint to rotate, and through the transmission of the joint motion, the entire three-drive expandable mechanical arm can be rotated together.

As shown in Figures 2 and 3, the yaw ring 10 and the first joint casing 12 are connected through bearings 11, and the bearing 11 is nested between the yaw ring 10 and the first joint casing 12, when the drive unit 1, 34 drives the lead screw When the nuts 4, 30 act on the yaw ring 10 through the push rods 5, 28 and the connecting rods 8, 26, the yaw ring 10 yaws, drives the bearing 11 to yaw, and the bearing 11 drives the first joint shell 12 to yaw; and When the drive unit 33 rotates, it drives the first joint shell 12 and the inner shell of the bearing 11 to rotate, and the yaw ring does not rotate; in this way, the yaw of the first joint shell 12 inside can be controlled by controlling the yaw ring 10, but the yaw ring Does not rotate with the first joint.

As shown in Figures 4, 5, and 6, they are respectively the first joint housing 12, the cross shaft 13, and the joint housing 14 between the first joint and the second joint. The joint housings 12 and 14 are both hollow cylindrical, and the joint housing 12 and The joint shell 14 is connected by the cross shaft 13, and the two joint shells can swing up and down relative to each other. When the rotation axes of the two joint shells are not on the same straight line, the rotational motion can still be transmitted; the right end of the joint shell 12 and the left end of the joint shell 16 form a concave-convex limit Mechanism 22, the left end of the joint housing 14 is the convex part of the concave-convex limiting mechanism 23, and the right end of the joint housing 14 is the concave part of the concave-convex limiting mechanism 21.

As shown in Figure 7, the second joint housing 16 is connected to the joint housing 14 through the cross shaft 15, the left end of the second joint housing 16 is a concave-convex stop mechanism 22 convex part structure, and the convex part is matched with the groove at the right end of the joint housing 12, A concavo-convex limiting mechanism 21 is formed.

Figure 8 is a schematic diagram of the assembly of Figures 4, 5, 6, and 7. The components shown in Figure 4 and Figure 5 are connected by a cross shaft 13, and Figure 5 and Figure 6 are connected by a cross shaft 14, and the concave part at the right end of the joint housing 12 is connected to the joint housing 16. The convex part at the left end cooperates to form a concave-convex limiting mechanism 22; the surfaces of the two components that are concave-convex matched with each other can be deflected in any direction, and have the function of a spherical hinge, but it is slightly different from the spherical hinge. The concave surface and the convex surface are not in complete contact, and the The circular ring on the convex part shown in the figure can play a position-limiting role when the concave-convex surface cooperates and rotates, so that the two components that the concave-convex surface cooperates rotate relative to a certain angle and stop moving.

As shown in FIG. 9 , it is a ring 20 that can rotate around the corresponding rotation pair of the second joint housing 16 . The shaft in the middle of the ring acts as a support for the end effector interface 18 , and the end effector interface 18 can rotate around the axis.

The working principle of the three-drive expandable robotic arm is mainly divided into the following four motion modes:

(1) Two driving units simultaneously push the push rods: when the driving units 1 and 34 rotate at the same time to drive the lead screws 3 and 31 respectively, the lead screws push the push rods 5 and 28 through the lead screw nuts 4 and 30, and the push rods 5 and 28 respectively drive The connecting rods 8 and 26 act on the yaw ring 10. After the yaw ring 10 receives the joint action of the two thrusts, it is equivalent to being subjected to a bending moment, so that it rotates and tilts upwards around the fixed seat 24 (as shown in Figure 11), driving and The first joint housing 12 connected by the bearing 11 rotates upwards and tilts; the first joint housing 12 drives the first joint and the second joint housing 14 to rotate upwards and tilts around the fixed seat 24 through the cross shaft 13, and due to the limitation of the concave and convex Due to the existence of the positioning mechanism 23, the first joint and the second joint housing 14 can only tilt upward to a certain angle relative to the first joint housing 12; at the same time, the rotating and tilting joint housing 14 drives the second joint housing 14 through the linkage action of the cross shaft 15. The two-joint shell 16 rotates upwards at a certain angle with the groove of the concave-convex limiting mechanism 22 as the fulcrum; finally, through the support and guidance of the concave-convex limiting mechanism 21 and the ring 20, the end effector interface 18 will be concave and convex with the concave-convex limiting mechanism 21. The groove is the fulcrum and the joint casing 16 is inclined at a certain angle; thus, through the accumulation of joint deflection angles, the entire mechanical arm bends upward to form a circular arc; the drive unit 33 drives each joint to rotate, and the entire mechanical arm together with the claws can simultaneously rotate. The overall structure of the three-drive expandable manipulator after deflection is shown in Figure 11;

(2) Two drive units pull the push rods simultaneously: when the drive units 1 and 34 rotate simultaneously to drive the lead screws 3 and 31 respectively, the lead screws pull the push rods 5 and 28 through the lead screw nuts 4 and 30, and the push rods 5 and 28 respectively drive The connecting rods 8 and 26 act on the yaw ring 10. After the yaw ring 10 is subjected to the joint action of the two pulling forces, it is equivalent to being subjected to a bending moment, so that it rotates and tilts downward around the fixed seat 24 (as shown in Figure 12), driving The first joint housing 12 connected to it through the bearing 11 rotates downward and tilts; the first joint housing 12 drives the first joint and the second joint housing 14 to rotate and tilt downward around the fixed seat 24 through the cross shaft 13 , and Due to the existence of the concave-convex limiting mechanism 23, the first joint and the second joint housing 14 can only tilt downward to a certain angle relative to the first joint housing 12; function, driving the second joint housing 16 to rotate and tilt downward at a certain angle with the groove of the concave-convex limiting mechanism 22 as the fulcrum; The groove of the limit mechanism 21 is the fulcrum and tilts at a certain angle with the joint shell 16; thus, through the accumulation of joint deflection angles, the entire mechanical arm bends downward to form a circular arc; the drive unit 33 drives each joint to rotate, and the entire mechanical arm The arm, together with the gripper, can rotate simultaneously. The overall structure of the three-drive expandable manipulator after deflection is shown in Figure 12;

(3) One drive unit pushes the push rod, and one drive unit pulls the push rod: when the drive unit 1 rotates to drive the lead screw 3, the lead screw pushes the push rod 5 through the lead screw nut 4, and the push rod drives the connecting rod 28 to the yaw ring 10 When a thrust is applied, the driving unit 34 rotates to drive the lead screw 31, and the lead screw pulls the push rod 28 through the lead screw nut 30. When the push rod drives the connecting rod 26 to apply a pulling force to the yaw ring 10, the yaw ring 10 receives a thrust and a After the combined action of the pulling force, it is equivalent to being subjected to a bending moment, thereby rotating and tilting downward around the fixed seat 24 (as shown in Figure 13), driving the first joint shell 12 connected to it through the bearing 11 to rotate and tilt downward; the first The joint housing 12 drives the first joint and the second joint housing 14 to rotate and tilt downward around the fixed seat 24 through the cross shaft 13 , and due to the existence of the concave-convex limit mechanism 23 , the first joint and the second joint housing 14 are opposite to each other. Because the first joint housing 12 can only be tilted at a certain angle; at the same time, the rotating and tilting joint housing 14 is driven by the linkage action of the cross shaft 15 to drive the second joint housing 16 to rotate downward with the groove of the concave-convex limiting mechanism 22 as the fulcrum Tilt at a certain angle; finally, through the supporting and guiding effect of the concave-convex limiting mechanism 21 and the ring 20, the end effector interface 18 will use the groove of the concave-convex limiting mechanism 21 as the fulcrum to tilt a certain angle along with the joint shell 16; thus, through As the angles of joint deflection accumulate, the entire robotic arm bends more and more upwards to form a circular arc; the drive unit 33 drives each joint to rotate, and the entire robotic arm together with the claws can rotate simultaneously. The overall structure of the three-drive expandable manipulator after deflection is shown in Figure 13;

(4) One drive unit pulls the push rod, and one drive unit pushes the push rod: when the drive unit 1 rotates to drive the lead screw 3, the lead screw pulls the push rod 5 through the lead screw nut 4, and the push rod drives the connecting rod 28 to the yaw ring 10 When a pulling force is applied, the driving unit 34 rotates to drive the lead screw 31, and the lead screw pushes the push rod 28 through the lead screw nut 30. After the joint action of the thrust, it is equivalent to being subjected to a bending moment, thereby rotating and tilting upward around the fixed seat 24 (as shown in Figure 14), driving the first joint housing 12 connected to it through the bearing 11 to rotate upward and tilting; the first joint housing 12 Through the cross shaft 13, the first joint and the second joint shell 14 are rotated and tilted upward around the fixed seat 24 as a fulcrum, and due to the existence of the concave-convex limit mechanism 23, the first joint and the second joint shell 14 are relative to the first The joint housing 12 can only be tilted to a certain angle; at the same time, the joint housing 14 that rotates and tilts through the linkage action of the cross shaft 15 drives the second joint housing 16 to rotate upwards and tilt upwards with the groove of the concave-convex limiting mechanism 22 as the fulcrum. Angle; Finally, through the supporting and guiding effect of the concave-convex limiting mechanism 21 and the ring 20, the end effector interface 18 will take the groove of the concave-convex limiting mechanism 21 as the fulcrum and tilt upward at a certain angle with the joint shell 16; thus, through the joint deflection As the angle of the pendulum accumulates, the entire mechanical arm bends upwards to form a circular arc; through the drive unit 33 , each joint is driven to rotate, and the entire mechanical arm together with the claws can rotate simultaneously. The overall structure of the three-drive expandable manipulator after deflection is shown in Figure 14.

To sum up, through the coordinated control of the two drive units 1 and 34, the three-drive expandable manipulator can be deflected in a wide range, and by controlling the drive unit 33, the three-drive expandable manipulator can be rotated as a whole; thus, combined The three-drive expandable robotic arm with overall yaw and rotation functions can conveniently and dexterously grasp and capture space targets.

Claims (5)

1. A three-drive expandable mechanical arm, comprising a drive unit, a leading screw, a leading screw nut and a push rod, a connecting rod, a yaw ring, a joint, an annulus and an end effector interface, characterized in that: The drive unit is a combination of a rotary motor and a harmonic reducer, installed on the base of the three-drive expandable mechanical arm, and the lead screw is connected to the output shaft of the drive unit through a coupling to drive the lead screw nut Do reciprocating linear motion, the lead screw nut drives the push rod to do reciprocating linear motion, the push rod is hinged with one end of the connecting rod, the other end of the connecting rod is hinged with the outer wall of the yaw ring, the joints are cross shafts, joint shells and concave-convex limiters A combination of mechanisms, the circular ring has a diameter shaft, the circular ring and the joint shell are connected by pins, and the end effector interface is flange type, which can be connected with different types of end effectors. 2. The mechanical arm according to claim 1, characterized in that: the three-drive expandable mechanical arm includes three drive units, two of which are connected to the lead screw through a coupling, and are sequentially passed through the lead screw nut, connecting The force transmission of the rod and the push rod realizes the up and down and left and right yaw movements of the yaw ring. The third drive unit is connected with the input end of the first joint through a coupling to realize the overall integration of the three-drive expandable mechanical arm around its own axis. Rotational movement. 3. The mechanical arm according to claim 2, characterized in that: the lead screw drives the push rod to perform reciprocating linear motion through the lead screw nut, and the push rod is hinged to the outer wall of the deflection ring through the connecting rod. 4. The mechanical arm according to claim 3, characterized in that: the joint structure has scalability, the output end of the previous joint is also the input end of the latter joint, and the three-drive expandable mechanical arm structure of the joint The number can be expanded to N, where N is a natural number; the concave-convex limit mechanism in the joint has the omnidirectional rotation function of the spherical joint, and at the same time is limited by the concave-convex structure, which plays a role in the movement process of the three-drive expandable mechanical arm. to positioning and orientation. 5. The mechanical arm according to claim 4, characterized in that: the cross shaft of the previous joint is connected with the cross shaft of the rear joint through the joint housing, and the deflection ring is deflected under the push-pull force generated by the push rod. pendulum, which drives the cross shaft in the first joint to deflect, and the cross shaft in the first joint will drive the cross shaft in the second joint to deflect through the joint shell between the first and second joints, and at the same time, the cross shaft in the first joint The concave-convex limit mechanism is used as the fulcrum and limit of the second joint deflection; the subsequent motion transmission principle is the same as the above-mentioned principle, through the accumulation of multiple joint deflection motions, the three-drive expandable manipulator can achieve a wide range of deflection sports.

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