Steel belt transmission mechanism for remote center movement of minimally invasive surgery robot
Technical Field
The invention relates to the technical field of medical robots, in particular to a transmission mechanism of a minimally invasive surgery robot.
Background
Minimally invasive surgery is a new technique for performing surgery in a human body by using an endoscope and the like. Compared with the traditional open surgery, the minimally invasive surgery has small wound and light damage to tissues, so that the time for healing the patient can be effectively shortened, and the pain of the patient caused by the open surgery is relieved. The population base of China is large, the requirements of people on advanced medical technology and conditions are increasingly increased, and the minimally invasive surgery has great development prospect in China with unique advantages.
During the operation of the operation, the most important is to ensure that the end surgical instrument passes through a remote central motion point, namely a fixed point, and ensure the stability and the accuracy of the position of the operation place for opening relative to the body of a patient. Errors can accumulate during the transmission process of the robot of the medical instrument, and seemingly small errors can be accumulated to be large at last, so that the position of an immobile point can be shifted, the operation can fail, and the life of a patient can be endangered.
Typical minimally invasive surgical robot transmission structures include joints and linkages to provide different modes of motion. With the development of the technology, the transmission mode also undergoes various changes, and the fixed point is ensured to be accurately and stably, including two aspects of electrical control and mechanical transmission, wherein the main aspect is the mechanical transmission part. In terms of large aspect, in long-distance transmission, common belt transmission, synchronous toothed belt transmission, rack transmission or steel wire rope transmission is generally used, most of the long-distance transmission is difficult to realize precise transmission, and the long-distance transmission has the advantages of difficult pre-tightening, non-compact structure, large occupied space and narrow application range compared with the transmission modes: has the advantages of traditional belt transmission, and can transmit motion and power remotely; the transmission mode is simple, the occupied space is small, and the transmission structure is compact; the proper pre-tightening can ensure the synchronous precision of the upper and lower steel belts, thus realizing the precise transmission of the steel belts.
Disclosure of Invention
The invention mainly relates to a novel transmission mechanism designed for realizing that a minimally invasive robot tail end surgical instrument passes through a fixed point. The traditional method for realizing the fixed point mainly comprises two methods, one is transmission of a connecting rod structure, and the transmission mode has the advantages of complex and heavy structure, slow execution action, poor stability and low transmission precision; the other is steel wire rope transmission, and the steel wire rope is difficult to pre-tighten, complex in wire walking and capable of shaking due to mutual coupling. The transmission structure uses steel belt transmission, has the advantages of good synchronism, no slipping, high transmission efficiency, wide application range and the like, and can realize precise transmission, thereby ensuring the position precision of a fixed point. Meanwhile, the steel belt has good rigidity, can increase the bearing capacity of the minimally invasive surgery robot, and has compact structure.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a steel belt transmission mechanism for remote central movement of a fixed point of a minimally invasive surgery robot comprises a framework, a power system and a mechanical transmission system. The skeleton mainly plays a role in supporting and installing elements, and various poses and motions of the minimally invasive surgical robot are realized by driving the skeleton, which is similar to human skeleton; the power system provides transmission energy for the transmission system; the transmission system enables the framework to keep a certain relative position relationship, and the position accuracy of the tail end motionless point is ensured.
The framework mainly comprises a rotating arm, a corner, a large arm, a middle arm, a small arm, a telescopic arm and the like. The rotating arm and the corner provide an installation base body for the power system, the large arm is fixed with the sleeve through the hexagon socket head cap screw, the sleeve is fixed with the corner through the screw, so that the large arm does not rotate, the large arm and the middle arm, the middle arm and the small arm are connected together in a matched mode through the crossed roller bearings and can rotate relative to each other, and the telescopic arm is fixed with the six belt wheels through the U-shaped block.
The power system consists of a motor, a speed reducer and a brake. The power system is mainly distributed on the corner and the rotating arm and provides power for rotating the minimally invasive surgery robot.
The transmission device consists of six different belt wheels, a steel belt, a fixed pre-tightening block and two fixed blocks. The power is transmitted to a first belt wheel firstly, the first belt wheel transmits the power to a second belt wheel through a steel belt, the second belt wheel is fixed with a middle arm by an inner hexagon bolt penetrating through an inner ring of a crossed roller bearing, one end of a third belt wheel is fixed on the big arm by a first fixing block, and the other end of the third belt wheel transmits the power to a fourth belt wheel through the steel belt; in a similar way, the belt wheel IV penetrates through the inner ring of the crossed roller bearing by an inner hexagon bolt and is fixed with the small arm, one end of the belt wheel V is fixed on the middle arm by the fixing block II, and the other end of the belt wheel V transmits power to the belt wheel VI connected with the tail end telescopic arm through a steel belt.
The invention has the following advantages:
1. the invention adopts steel belt transmission, has good steel belt synchronization characteristic, convenient pre-tightening and high rigidity, can ensure that the minimally invasive surgery robot has compact structure and strong bearing capacity, is easy to realize precise transmission, and overcomes the defects of complicated and fussy rod transmission and steel wire rope transmission structure, inflexible motion, low precision and the like.
2. The invention has compact and reasonable structure, small occupied space and flexible operation.
3. The steel belt transmission system adopts two belts to control one degree of freedom, the steel belts are fixed on the belt pulley in a staggered mode in space and are not mutually coupled, and the steel belts are wound in opposite directions for half a turn to be fixed, so that the space is greatly saved, and the adjustment and the maintenance are convenient. The problems of complex wire walking, mutual coupling, jitter and the like caused by steel wire rope transmission can be effectively solved.
4. The transmission system adopted by the invention has relative rotation motion during transmission, namely the motion of the belt wheel and the motion of the arm have relative rotation motion, so that the large arm and the small arm can be kept parallel, and the angle between the middle arm and the telescopic arm is unchanged, thereby ensuring the accuracy of the position of the motionless point and ensuring the continuous and stable motion of each arm.
5. The U-shaped block at the tail end of the minimally invasive surgery robot is additionally provided with a limit position, so that the minimally invasive surgery robot can only swing within a certain angle range.
6. The transmission structure of the invention is not only suitable for minimally invasive surgery robots, but also suitable for industrial robots or other mechanical arms.
7. Each connecting piece of the invention adopts a hollow structure, thereby being beneficial to the installation and wiring of the controller.
8. The invention designs a method for keeping the initial relative position of each minimally invasive surgery robot, thereby improving the installation precision, ensuring the relative position precision of the minimally invasive surgery robot in the movement process and improving the position precision of the terminal immobile point.
Drawings
FIG. 1 is a view showing the overall appearance of a minimally invasive surgical robot to which the steel belt transmission of the present invention is applied;
FIG. 2 is a sectional view showing the construction of the present invention in which power is transmitted to the middle arm through the large arm;
FIG. 3 is an overall structure diagram of the internal steel belt transmission of the minimally invasive surgical robot of the invention;
FIG. 4 is a schematic diagram of the transmission of the present invention to achieve a fixed point;
FIG. 5 is a diagram of a limiting device of a minimally invasive surgical robot according to the present invention;
FIG. 6 is a view of the minimally invasive surgical robot of the present invention in an extreme position;
Detailed Description
The present invention will be described in detail with reference to specific examples.
The invention relates to a steel belt transmission mechanism for a minimally invasive surgery robot, which is used for ensuring the position precision of a tail end fixed point, and mainly solves the problems in two aspects in view of the conditions that the structure of the tail end fixed point is complicated and the stability is not high due to the rod transmission and the steel wire rope transmission: the problems of complex and heavy connecting rod transmission structure, slow execution action and low transmission precision are solved; the problems of difficult transmission pre-tightening, complex wire moving, mutual coupling and shaking of the steel wire rope are solved.
Fig. 1 is a diagram showing an overall appearance structure of the minimally invasive surgical robot using the steel belt transmission according to the present invention, wherein the minimally invasive surgical robot transmission structure includes a frame 1, a power system 2, and a transmission system 3. The framework 1 comprises a rotating arm 1-1, a corner 1-2, a large arm 1-3, a middle arm 1-4, a small arm 1-5 and a telescopic arm 1-6, wherein the large arm 1-3 is fixedly connected with a sleeve 2-6, and the large arm 1-3, the middle arm 1-4 and the small arm 1-5 are connected through crossed roller bearings and can rotate relative to each other. The tail end of the transmission system 3 is connected with the telescopic arms 1-6 through U-shaped blocks 3-11, the surgical instruments 4 are arranged on the telescopic arms 1-6, and finally two rotational degrees of freedom R1 and R2 are achieved.
As shown in figure 2, the structural section that power is transmitted to the middle arm through the big arm is shown, the big arm 1-3 is fixed on the sleeve 2-6 by the hexagon socket head cap screw, the sleeve 2-6 is fixed on the corner 1-2 by the hexagon socket head cap screw, so that the big arm 1-3 can not rotate. The power is firstly transmitted to a belt wheel I3-2, the belt wheel I3-2 is connected with a belt wheel II 3-4 through a steel belt 3-3-1 and transmits torque, the belt wheel II 3-4 is fixed with a crossed roller bearing inner ring 3-11-1 through an inner hexagon bolt, a middle arm 1-4 is fixed with the crossed roller bearing inner ring 3-11-1 through the inner hexagon bolt, the belt wheel II 3-4 can drive the middle arm 1-4 to rotate at the same angle by rotating, one end of the belt wheel III 3-6 is fixed on a large arm 1-3 through a fixing block I3-5, and the first fixed block 3-5 is provided with a wire groove 3-5-1 which is convenient for the controller to run, and the other end of the third belt wheel 3-6 is connected with the belt wheel of the next joint through two steel belts 3-3-3 and 3-4 which are staggered in space and wound in opposite directions.
FIG. 3 is a drawing of an overall structure of the internal steel belt transmission of the minimally invasive surgery robot of the invention, wherein a rotating arm 1-1 and a corner 1-2 provide an installation base for a power system of the minimally invasive surgery robot, the corner 1-2 is connected with the rotating arm 1-1, the power system 2 transmits power to a pulley I3-2, a fixed pre-tightening block 3-1 fixes a steel belt 3-3-1 on the pulley I1 and pre-tightens the steel belt, the steel belt 3-3-1 is connected to a pulley II 3-4 in the same way, similarly, the steel belt 3-3-2 connects the pulley I3-2 with the pulley II 3-4, the pulley II 3-4 is fixed with an inner ring of a cross roller bearing through an inner hexagon bolt, the middle arm 1-4 is also fixed with the inner ring of the cross roller bearing through the inner hexagon bolt, when the pulley I3-2 drives the pulley II 3-4 to, the middle arm 1-4 will also rotate through the same angle with it, resulting in a main rotational movement. One end of a belt wheel III 3-6 is fixed on the large arm by a first fixing block 3-5 through an inner hexagon bolt, the other end of the belt wheel III 3-6 is connected with a belt wheel IV 3-7 through two steel belts 3-3-3 and 3-4 which are staggered in space and wound in reverse directions, the belt wheel IV 3-7 is fixed with an inner ring of a crossed roller bearing through the inner hexagon bolt, a small arm 1-5 is fixed with the inner ring of the crossed roller bearing through the crossed roller bearing, when the belt wheel IV 3-7 rotates, the small arm 1-5 rotates at the same angle, one end of a belt wheel V3-9 is fixed on a middle arm 1-4 through the inner hexagon bolt by a second fixing block 3-8, the other end of the belt wheel V3-9 is also staggered in space, the steel belts 3-3-5 and 3-9 which are wound, The steel belt 3-3-6 is connected with the belt wheel six 3-10, the belt wheel six 3-10 is connected with the telescopic arm 1-6 through the U-shaped block 3-11, so that the belt wheel five 3-9 drives the belt wheel six 3-10 to rotate, and the belt wheel six 3-10 drives the telescopic arm to rotate at the same angle. The analysis shows that: the belt wheel I3-2, the belt wheel II 3-4 and the middle arm 1-4 fixedly connected with the belt wheel II 3-4 are main parts forming main rotary motion; the belt pulleys three 3-6, four 3-7, five 3-9, six 3-10 and the steel belt connecting the transmission between the belt pulleys are the main parts forming the relative rotation movement. The specific implementation modes of the main rotation motion and the relative rotation motion are as follows: one end of the steel belt 3-3-1 and one end of the steel belt 3-3-2 are connected with the belt wheel I3-2, and the other end of the steel belt 3-3-2 is connected with the belt wheel II 3-4, so that the belt wheel I3-2 can transmit power to the belt wheel II 3-4 and enable the belt wheel II to rotate, the belt wheel II 3-4 drives the middle arm 1-4 fixed with the belt wheel II to rotate to generate main motion, and under the action of the main motion, the mechanism generates two relative rotary motions, namely a first relative rotary motion: as the belt wheel III 3-6 is fixed on the large arm 1-3 by the fixing block I3-5, the belt wheel I3-2 transmits the power of the power system 2 to the belt wheel II 3-4, the belt wheel II 3-4 drives the middle arm 1-4 fixed with the belt wheel II to rotate, when the middle arm 1-4 rotates, the belt wheel III 3-6 reversely rotates at the same angle relative to the rotation direction of the middle arm 1-4, the belt wheel IV 3-7 is driven to rotate at the same angle relative to the rotation direction of the middle arm 1-4, and the belt wheel IV 3-7 drives the small arm 1-5 connected with the belt wheel IV to rotate at the same angle relative to the rotation direction of the middle arm 1-4, so that the small arm 1-5 and the large arm 1; second relative rotational movement: the belt wheel five 3-5 is fixed on the middle arm 1-4 by the fixing block two 3-8, under the action of the first relative rotation motion, namely the belt wheel four 3-7 drives the small arm 1-5 connected with the belt wheel four 3-7 to rotate in the same direction by the same angle, the belt wheel five 3-9 rotates in the same direction by the same angle relative to the rotating direction of the small arm 1-5, namely the belt wheel six 3-10 is driven to rotate in the same direction by the same angle as the rotating direction of the middle arm 1-4, and at the moment, the telescopic arm 1-6 connected with the belt wheel six 3-10 also rotates in the same direction by the same angle, so that the telescopic arm 1-6 and the middle arm 1-4 still keep the angle alpha at the initial moment unchanged, and the fixed point is realized.
In order to make the joints more clear and the transmission principle more clear, in fig. 4, the skeleton is indicated by a chain line.
Fig. 4 is a schematic diagram of a transmission for realizing a stationary point according to the present invention, and a specific embodiment for realizing the stationary point is as follows: the motor 2-7 transmits power to the belt wheel I3-2, the belt wheel I3-2 is staggered through space, the steel belt 3-3-1 wound in the reverse direction and the steel belt 3-3-2 transmit power to the belt wheel II 3-4, the belt wheel II 3-4 drives the middle arm 1-4 to rotate to generate main rotation movement, the rotation directions of the belt wheel I3-2, the belt wheel II 3-4 and the middle arm 1-4 in the main rotation movement are the same, and at the moment, the big arm 1-3 and the small arm 1-5 are still parallel. When the middle arm 1-4 rotates, the belt wheel III 3-6 and the large arm 1-3 are fixed together by the fixing block I3-5 through the inner hexagon bolt, the belt wheel V3-9 and the middle arm 1-4 are fixed together by the fixing block II 3-8 through the inner hexagon bolt, conditions are provided for relative rotation movement, when the middle arm 1-4 rotates, the belt wheel III 3-6 reversely rotates at the same angle relative to the middle arm 1-4, the belt wheel IV 3-7 connected with the belt wheel III is driven to rotate, relative rotation movement is generated, and the rotation direction is opposite to that of the middle arm 1-4; the belt wheel IV 3-7 drives the small arm 1-5 connected with the belt wheel IV to rotate, when the small arm 1-5 rotates, the belt wheel V3-9 reversely rotates by the same angle relative to the small arm 1-5, drives the belt wheel VI 3-10 connected with the belt wheel V to rotate by the same angle in the same direction, and leads the telescopic arm 1-6 to rotate by the same angle to generate another relative rotation movement. After two times of relative reverse rotation movement, the rotation direction of the telescopic arms 1-6 is the same as that of the middle arms 1-4, and the telescopic arms rotate by the same angle, so that the angle alpha between the telescopic arms 1-6 and the middle arms 1-4 is unchanged, and the position accuracy of the immobile point is ensured by utilizing the parallelogram principle.
As shown in figure 5, which is a diagram of the limiting device of the minimally invasive surgery robot, a small boss 3-11-1 is arranged on a U-shaped block 3-11, the small boss 3-11-1 slides in a groove 1-5-1 on a small arm cover 1-5, and the rotation angle range is 140 degrees, so that the minimally invasive surgery robot can only swing within a certain angle range.
FIG. 6 is a diagram of a structure of a minimally invasive surgery robot at a limit position, in order to ensure the accuracy of an initial assembly position, positioning pin holes are respectively designed on a second pulley 3-4 and a fourth pulley 3-7, and positioning pin holes 3-5-1 and 3-8-1 are respectively designed on corresponding positions of a first fixing block 3-5 and a second fixing block 3-8, when the minimally invasive surgery robot is assembled, a tail end telescopic arm 1-6 is positioned at the limit position and forms an angle alpha with a middle arm 1-4, so that the big arm 1-3 and the small arm 1-5 are kept parallel, a pin is inserted into the corresponding positioning pin hole 3-5-1 and 3-8-1, then a steel belt is installed, the positioning pin is pulled out after the steel belt is installed and pre-tightened, so that the big arm 1-3, the middle arm 1-4, the small arm 1-5 and the telescopic arm 1-6 jointly form a special parallelogram, the relative position of each arm in the initial state is ensured to be accurate.
The foregoing is merely illustrative of the present invention. The present invention is not limited to the above-described embodiments, and various changes or modifications within the scope of the claims may be made by those skilled in the art without affecting the scope of the present invention.