A flexible actuator, connecting device and robot for assisting ultrasonic inspection

Abstract

The present invention discloses a flexible actuator for assisting ultrasonic examination, comprising a flexible body and a connecting tube; a first cavity is provided in the flexible body, the connecting tube is installed at the end of the flexible body, and one end of the connecting tube is connected to the first cavity; the connecting tube is used to introduce external liquid or gas into the first cavity, and then drive the flexible body to deform by pressure; an anti-radial expansion mechanism is also installed in the flexible body, and the anti-radial expansion mechanism is used to limit its radial expansion when the flexible body is deformed, and can only perform telescopic movement in the axial direction of the flexible body. The present invention can assist medical personnel in performing ultrasonic examinations or other medical injections, so as to improve diagnostic efficiency and accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible robots, and in particular to a flexible actuator, a connecting device and a robot for assisting ultrasonic inspection. Background Art

[0002] With the acceleration of the aging trend of society and the rising incidence of major diseases, clinical requirements for the quality and coverage of medical examinations are higher. Ultrasound, with its characteristics of no radiation and wide applicability, has become one of the preferred medical imaging examination methods in clinical practice. However, due to factors such as uneven distribution of medical resources and shortage of relevant talents, medical institutions are in urgent need of intelligent expansion of equipment to improve diagnostic efficiency and accuracy. Therefore, there is an urgent need for a flexible robot for assisting ultrasound examinations to assist doctors in diagnosis. Summary of the invention

[0003] The purpose of the present invention is to provide a flexible actuator, a connecting device and a robot for assisting ultrasonic examination, so as to assist medical personnel in performing ultrasonic examination or other medical injections, so as to improve diagnostic efficiency and accuracy.

[0004] In order to achieve the above purpose, the following technical solutions are adopted:

[0005] A flexible actuator for assisting ultrasonic inspection comprises a flexible body and a connecting tube; a first cavity is opened in the flexible body, the connecting tube is installed at the end of the flexible body, and one end of the connecting tube passes through the first cavity; the connecting tube is used to introduce external liquid or gas into the first cavity, thereby driving the flexible body to deform through pressure; an anti-radial expansion mechanism is also installed in the flexible body, and the anti-radial expansion mechanism is used to limit its radial expansion when the flexible body is deformed, so that it can only perform telescopic movement in the axial direction of the flexible body.

[0006] Furthermore, the first cavity is opened inside the flexible body along its length direction; the anti-radial expansion mechanism is made of a retractable material, is sleeved on the outside of the first cavity, and its two ends are connected to the inner walls of the flexible body.

[0007] Furthermore, the anti-radial expansion mechanism may adopt any one of the following mechanisms: a spring, a telescopic mesh tube.

[0008] Furthermore, the flexible body includes a flexible tube and two sealing end covers; the first cavity is opened inside the flexible tube, and the two sealing end covers are respectively arranged at one end of the flexible tube and seal it; the connecting tube is installed on one of the sealing end covers.

[0009] Furthermore, the flexible body is made of a deformable flexible material.

[0010] In order to achieve the above-mentioned purpose, a flexible connection device for assisting ultrasonic inspection is also provided, including a bottom plate, a top plate, and several of the above-mentioned flexible actuators; several of the flexible actuators are movably connected between the bottom plate and the top plate, and each flexible actuator is also connected to a pressure sensor, which is used to monitor the internal pressure of the flexible actuator.

[0011] Furthermore, a plurality of connecting joints are installed on the top plate and the bottom plate, and each connecting joint has at least two degrees of freedom; a plurality of the flexible actuators are arranged in an interval in the circumferential direction between the bottom plate and the top plate, and the two ends of each flexible actuator are respectively movably connected to the bottom plate and the top plate via a connecting joint.

[0012] Furthermore, the connection joint adopts any one of the following mechanisms: a spherical rotating joint, a universal joint.

[0013] To achieve the above objectives, a flexible robot for assisting ultrasonic inspection is also provided, including a robotic arm RCM mechanism and the above-mentioned flexible connection device; the robotic arm RCM mechanism is drivingly connected to the flexible connection device, and the top plate or bottom plate of the flexible connection device is used to install ultrasonic detection equipment.

[0014] By adopting the above scheme, the beneficial effects of the present invention are:

[0015] 1) The flexible actuator is provided with an anti-radial expansion mechanism, which can be used to limit the radial expansion of the flexible body when it is deformed, so that it can only perform telescopic movement in the axial direction of the flexible body, thereby ensuring that the position and force of the flexible robot controlled by the flexible actuator are simpler and more accurate when the ultrasonic detection equipment is working;

[0016] 2) The flexible connection device is provided with 6 flexible actuators, and each flexible actuator is connected to a pressure sensor, which can provide feedback of six-axis force and torque without the need for other sensing equipment, is easy to use, and can reduce costs;

[0017] 3) The flexible robot is equipped with a robotic arm RCM mechanism with a high degree of automation. When used in ultrasonic inspection, it can improve detection efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of the flexible robot of the present invention;

[0019] Figure 2 is a three-dimensional diagram of the flexible connection device of the present invention;

[0020] Figure 3 A schematic diagram showing the external structure comparison of the flexible actuator of the present invention when driven by different pressures;

[0021] Figure 4 Schematic diagram of the internal structure comparison of the flexible actuator of the present invention under different pressure driving;

[0022] Figure 5 It is a schematic diagram of the internal pressure direction of the flexible actuator of the present invention;

[0023] Figure 6 A schematic diagram of the relationship between the elongation of a flexible actuator and its internal pressure in one embodiment of the present invention;

[0024] Figure 7 This is a schematic diagram of the movement direction of the flexible connection device in one embodiment of the present invention;

[0025] The accompanying drawings illustrate:

[0026] 1—Flexible actuator; 2—Anti-radial expansion mechanism;

[0027] 3—bottom plate; 4—top plate;

[0028] 5—connection joint; 6—Robotic arm RCM mechanism;

[0029] 7—flexible connection device; 11—flexible pipe;

[0030] 12—sealing end cover; 13—connecting pipe;

[0031] 14—First cavity. DETAILED DESCRIPTION

[0032] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0033] Reference Figures 1 to 7 As shown, the present invention provides a flexible actuator for assisting ultrasonic inspection, including a flexible body and a connecting tube 13; a first cavity 14 is opened in the flexible body, the connecting tube 13 is installed at the end of the flexible body, and one end of the connecting tube 13 passes through the first cavity 14; the connecting tube 13 is used to introduce external liquid or gas into the first cavity 14, and then drive the flexible body to deform by pressure; an anti-radial expansion mechanism 2 is also installed in the flexible body, and the anti-radial expansion mechanism 2 is used to limit its radial expansion when the flexible body is deformed, and can only perform telescopic movement in the axial direction of the flexible body.

[0034] Among them, the first cavity 14 is opened inside the flexible body along the length direction thereof; the anti-radial expansion mechanism 2 is made of a retractable material, and the anti-radial expansion mechanism 2 is sleeved on the outside of the first cavity 14, and its two ends are connected to the inner walls of the two ends of the flexible body; the anti-radial expansion mechanism 2 can adopt any one of the following mechanisms: a spring, a retractable mesh tube; the flexible body includes a flexible tube 11 and two sealed end covers 12; the first cavity 14 is opened inside the flexible tube 11, and the two sealed end covers 12 are respectively arranged at one end of the flexible tube 11 and seal it; the connecting tube 13 is installed on one of the sealed end covers 12; the flexible body is made of a flexible material that can produce deformation.

[0035] A flexible connection device for assisting ultrasonic inspection is also provided, comprising a bottom plate 3, a top plate 4, and a plurality of the above-mentioned flexible actuators 1; the plurality of the flexible actuators 1 are movably connected between the bottom plate 3 and the top plate 4, and each flexible actuator 1 is also connected to a pressure sensor, which is used to monitor the internal pressure of the flexible actuator 1.

[0036] Among them, a number of connecting joints 5 are also installed on the top plate 4 and the bottom plate 3, and each connecting joint 5 has at least two degrees of freedom; a number of the flexible actuators 1 are arranged between the bottom plate 3 and the top plate 4 at intervals in the circumferential direction, and the two ends of each flexible actuator 1 are respectively movably connected to the bottom plate 3 and the top plate 4 through a connecting joint 5; the connecting joint 5 adopts any one of the following mechanisms: a spherical rotating joint, a universal joint.

[0037] A flexible robot for assisting ultrasonic inspection is also provided, comprising a robotic arm RCM mechanism 6 and the above-mentioned flexible connection device 7; the robotic arm RCM mechanism 6 is drivingly connected to the flexible connection device 7, and the top plate 4 or bottom plate 3 of the flexible connection device 7 is used to install ultrasonic detection equipment.

[0038] Working principle of the present invention:

[0039] Continue to refer to Figures 1 to 7 As shown, in one embodiment, the present invention provides a flexible actuator, the flexible actuator 1 is made of a flexible material that can generate deformation, such as silicone, rubber and some polymer materials, and there is also a pressure cavity (first cavity 14) inside the flexible actuator 1. When the pressure in the pressure cavity changes, the flexible actuator 1 will be deformed. At the same time, an anti-radial expansion mechanism 2 is arranged inside the flexible actuator 1. When the flexible body is deformed, the radial expansion of the flexible body is limited, and the flexible body can only perform telescopic movement in the axial direction of the flexible body. The flexible actuator is made of a telescopic material, such as a spring, a telescopic mesh tube, or other spiral, mesh, tubular structures, etc.; specifically, refer to Figure 3 and Figure 4As shown in (a) and (b) in FIG. 1 , P1 and P2 represent different pressure input states of liquid or gas, wherein the pressure of the gas or liquid input in the P2 state is greater than the pressure of the gas or liquid input in the P1 state. Therefore, the axial elongation of the flexible actuator 1 in the P2 state is greater than that in the P1 state. The axial elongation is generated by the pressure difference in the first cavity 14, as shown in FIG. Figure 5 As shown, when liquid or gas is applied to the first cavity 14 through the connecting pipe 13, the internal pressure of the first cavity 14 will be applied to the inner wall of the first cavity 14, which will cause the flexible body to expand in volume. In order to prevent the flexible body from expanding in the radial direction, a retractable anti-radial expansion mechanism 2 such as a spring or a retractable mesh tube is provided on its outer side to limit its radial expansion, so that the flexible body can only perform retractable movement in the axial direction of the flexible body, such as Figure 6 As shown, it is a relationship diagram between the elongation of the flexible actuator 1 and its internal pressure. Depending on the structure and material used in the flexible actuator 1, the elongation of the flexible actuator 1 and its internal pressure may be linearly or nonlinearly related.

[0040] In another embodiment, the present invention further provides a flexible connection device, and in this embodiment, the number of flexible actuators 1 is set to 6 (the number of flexible actuators 1 can be designed to allow a corresponding number of motion axes to move and a corresponding number of axis force sensing mechanisms, such as in this embodiment, the number of flexible actuators 1 is set to 6, which can provide 6 degrees of freedom of movement), the flexible robot is designed based on the 6 flexible actuators 1 in parallel, and can move with six degrees of freedom; specifically, the 6 flexible actuators 1 are arranged in a circumferential direction between the bottom plate 3 and the top plate 4 at intervals, and the two ends of each flexible actuator 1 are respectively connected to the bottom plate 3 and the top plate 4 through a connecting joint 5; the connecting joint 5 has at least two degrees of freedom, and a spherical rotating joint or a universal joint can be used; due to the provision of the connecting joint 5, the flexible actuator 1 in the hexapod parallel mechanism can only be extended and shortened axially, and in specific applications, an external ultrasonic detection device can be installed on the top plate 4 or the bottom plate 3, and based on the working principle of the flexible actuator 1, the contact between the ultrasonic detection device and the human body is compliant and fit.

[0041] In another embodiment, the present invention further provides a flexible robot, which is designed to generate only axial pressure when performing multi-axis motion and applying external forces and torques. The robot includes a manipulator RCM mechanism 6 and a flexible connection device 7. The manipulator RCM mechanism 6 has three degrees of freedom, which can expand the working space of the flexible robot. In addition, the flexible robot can realize six-axis free motion and feedback control in space, and because the pressure sensor (the pressure sensor is connected to the connecting pipe 13 of the flexible actuator 1, and can monitor the internal pressure of the flexible tube 11, and monitor the force at the end of the flexible connection device 7 according to the internal pressure, that is, the end posture of the flexible connection device 7 can be controlled by the pressure of the first cavity 14 inside the flexible tube 11) and the deformable flexible actuator 1 The existence of (the position and posture of the ultrasonic detection equipment can be calculated by the volume feedback of the flexible actuator 1. Since the size of the first cavity 14 inside the flexible actuator 1 is determined, that is, its cross-sectional size remains unchanged, its length can be measured by an external measuring mechanism to obtain the volume of the liquid or gas filled in the first cavity 14. The measuring mechanism can use other measuring devices such as linear displacement potentiometers and motor encoders. The relationship between its internal volume and internal pressure can be obtained in advance through a calibration program. Therefore, the pressure difference caused by the external force can be measured by subtracting the pressure feedback value from the pressure sensor from the internal pressure from the volume measurement, and then the contact force and torque are calculated based on the pressure difference). The flexible robot can measure the force and torque of six axes in space. Specifically:

[0042] Reference Figure 7 As shown in the figure, the inverse kinematic solution of the flexible robot is as follows: First, the formula f i＝1to6 Calculate the length of each flexible actuator 1 required to reach the target position and orientation, where f i＝1to6 Indicates the required length of each flexible actuator 1 numbered 1 to 6.

[0043] f i =((x+((cosθ x ×cosθ y )×P xi )+(((cosθ x ×sinθ y ×sinθ x ))-sinθ x ×cosθ z ))×P xi )+(((cosθ x ×sinθ y ×sinθ z ))+(sin x θ×sinθ z )))×P zi )-b zi) 2 +(y+((cosθ z ×cosθ y )×P zi )+(((sinθ z ×sinθ y ×sinθ z ))+(cosθ z ×cosθ x ))×P yi )+(((cosθ z ×sinθ y ×sinθ z ))-(cosθ z ×sinθ z )))×P zi )-b yi ) 2 +(z+((-sinθ y )+P xi )+((cosθ y ×sinθ x ))×P yi )+((cosθ s ×cosθ y ))×P xi )-b xi ) 2 ) 0.5 -L i

[0044] Where b xi , b yi and b zi is the position of the connection joint 5 between the flexible actuator 1 and the base plate 3, p xi , p yi and p zi is the position of the connection joint 5 between the flexible actuator 1 and the top plate 4; each flexible actuator 1 will be connected to a pressure sensor, and the measured pressure data will be used to infer the length of the flexible actuator 1. Therefore, in the kinematic forward and inverse solutions, the actual length of each flexible actuator 1 is a known quantity; using the formula f i＝1to6The kinematics of the flexible robot can be solved positively, that is, the position, posture and orientation of the ultrasonic detection equipment can be calculated when the length of each flexible actuator 1 is known; the flexible robot is composed of six flexible actuators 1, and these six flexible actuators 1 not only make the flexible robot move in six degrees of freedom, but also respond to the external force applied to the ultrasonic detection equipment, thereby axially extending and shortening on their respective axes. Therefore, these six flexible actuators 1 are also six-axis torque sensors of the flexible robot; the posture state of the flexible robot is obtained by kinematically solving the pressure feedback values ​​of each flexible actuator 1. When an external force or torque q=[F x ,F y ,F z ,M x ,M y ,M z ] T When the flexible robot produces relative motion (P r ), relative motion (P r ) will be superimposed on the position state (P u ) on; after the ultrasonic detection device is applied with external force, the posture state of the flexible robot is P s =P r +P u ; Due to the relative movement after force (P r ), the length of the flexible actuator 1 will also change due to the external force it receives, (P r ) can be calculated from the pressure feedback value, (P u ) can be calculated by the volume feedback of the gas or liquid injected by the flexible actuator 1 (the volume feedback calculation method is as described above and will not be repeated here); therefore, the pressure difference change caused by the external force can be obtained by subtracting the pressure value measured by the pressure sensor after the flexible robot is subjected to the external force from the internal pressure value obtained by the volume measurement, that is, P s The Jacobian matrix (J) of the flexible ultrasonic robot and the pressure difference Δρ i The relative motion (P r ), its formula is expressed as:

[0045] P s =JΔρ i ,

[0046] The hardness matrix (K) and relative motion (P s ), using Hooke's law F = KP s The external force F can be calculated. Therefore, the external force F can be calculated from the pressure difference. The calculation formula is:

[0047] F=KJΔρ i ,

[0048] The hardness matrix and Jacobian matrix of the flexible robot are both 6x6 matrices. When the elongation of the flexible actuator 1 is linearly related to the pressure value, the calibration matrix (C=KJ) can be determined by the calibration results on the six axes; the flexible robot can move and rotate freely on the six axes in space while realizing the function of six-axis force sensing. And because it has these two functions at the same time, this flexible robot can move under force feedback control, thereby achieving gentle contact with the body of the object being detected.

[0049] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A flexible actuator for assisting ultrasonic inspection, characterized in that: The invention comprises a flexible body and a connecting pipe; a first cavity is formed in the flexible body, the connecting pipe is installed at the end of the flexible body, and one end of the connecting pipe passes through the first cavity; the connecting pipe is used to introduce external liquid or gas into the first cavity, and then drive the flexible body to deform by pressure; an anti-radial expansion mechanism is also installed in the flexible body, and the anti-radial expansion mechanism is used to limit the radial expansion of the flexible body when the flexible body is deformed, so that the flexible body can only perform telescopic movement in the axial direction; The first cavity is opened inside the flexible body along the length direction thereof; the anti-radial expansion mechanism is made of a retractable material, is sleeved on the outside of the first cavity, and has two ends connected to the inner walls of the two ends of the flexible body; The flexible body comprises a flexible tube and two sealing end covers; the first cavity is opened inside the flexible tube, and the two sealing end covers are respectively arranged at one end of the flexible tube and seal it; the connecting tube is installed on one of the sealing end covers.

2. The flexible actuator for assisting ultrasonic inspection according to claim 1, characterized in that: The anti-radial expansion mechanism may adopt any one of the following mechanisms: a spring, a telescopic mesh tube.

3. The flexible actuator for assisting ultrasonic inspection according to claim 1, characterized in that: The flexible body is made of a flexible material that can generate deformation.

4. A flexible connection device for assisting ultrasonic inspection, characterized in that: It includes a bottom plate, a top plate, and several flexible actuators as described in any one of claims 1 to 3; several of the flexible actuators are movably connected between the bottom plate and the top plate, and each flexible actuator is also connected to a pressure sensor, which is used to monitor the internal pressure of the flexible actuator.

5. The flexible connection device for assisting ultrasonic inspection according to claim 4, characterized in that: The top plate and the bottom plate are also equipped with a plurality of connecting joints, and each connecting joint has at least two degrees of freedom; a plurality of the flexible actuators are arranged between the bottom plate and the top plate at intervals in the circumferential direction, and the two ends of each flexible actuator are respectively movably connected to the bottom plate and the top plate via a connecting joint.

6. The flexible connection device for assisting ultrasonic inspection according to claim 5, characterized in that: The connecting joint adopts any one of the following mechanisms: a spherical rotating joint and a universal joint.

7. A flexible robot for assisting ultrasonic examination, characterized in that: It comprises a robot arm RCM mechanism and the flexible connection device described in any one of claims 4 to 6; the robot arm RCM mechanism is drivingly connected to the flexible connection device, and the top plate or bottom plate of the flexible connection device is used to install ultrasonic detection equipment.

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