Pre-tightening type quasi-zero stiffness connecting device for surgical robot

Abstract

A pre-tightening type quasi-zero stiffness connecting device of a surgical robot relates to the field of surgical robots and comprises a mechanical arm connecting mechanism and a quasi-zero stiffness connecting mechanism. The quasi-zero stiffness connecting mechanism comprises an adapter, a guide shaft, a connecting piece, a fixing nut, a tuning nut, a linear spring and a disc spring; the adapter is connected with the mechanical arm connecting mechanism; the connector is slidably connected with the guide shaft, the fixing nut and the tuning nut are both in threaded connection with the guide shaft, the linear spring is clamped between the adapter and the guide shaft, and the disc spring is clamped between the guide shaft and the connector. The device at least has the advantages of being high in vibration suppression efficiency, large in bearing capacity, wide in quasi-zero stiffness interval, controllable in interval and the like.

Description

Technical Field

[0001] This invention relates to the field of surgical robots, and more specifically, to a pre-tensioned quasi-zero stiffness connection device for surgical robots. Background Technology Surgical robots, with their advantages of precise positioning, surgical planning, accurate imaging, minimal invasiveness, and rapid postoperative recovery, have promoted the development of the medical industry while also bringing convenience and safety to doctors and patients. Compared with traditional surgery, surgical robots offer greater precision, minimal invasiveness, and safety. The robotic arm of a surgical robot drives the end effector or actuator through a connecting device. For different types of surgery, the precision, stiffness, and force feedback threshold of the robotic arm vary. For example, in orthopedic surgical robots, the high-speed movement of the end effector, such as a oscillating saw, can cause the robotic arm to vibrate, thus affecting surgical precision. The connecting device between the power unit and the robotic arm must not only have a connecting function but also provide good vibration isolation, ensuring overall stiffness while preventing or absorbing the energy from the vibration response of the power unit transmitted to the robotic arm.

[0002] The inventors discovered in their research that existing surgical robot stiffness connection devices have at least the following drawbacks: Poor vibration isolation performance results in a large force feedback amplitude to the robotic arm, affecting surgical precision and easily generating large impact loads. The structure stiffness and vibration reduction function are manually controlled to apply different working conditions, making it impossible to simultaneously possess both high stiffness and vibration reduction functions. Summary of the Invention

[0003] The present invention aims to provide, for example, a pre-tensioned quasi-zero stiffness connection device for surgical robots, which has advantages such as high vibration suppression efficiency, large load-bearing capacity, wide quasi-zero stiffness range, and controllable range.

[0004] The embodiments of the present invention can be implemented as follows: In a first aspect, the present invention provides a pre-tensioned quasi-zero stiffness connection device for a surgical robot, comprising: Robotic arm connection mechanism and quasi-zero stiffness connection mechanism; The quasi-zero stiffness connection mechanism includes an adapter, a guide shaft, a connector, a fixing nut, a tuning nut, a linear spring, and a disc spring. The adapter is connected to the robotic arm connection mechanism. The guide shaft is slidably connected to the adapter, and the two cooperate to define a first installation space. The connector is slidably connected to the guide shaft, and the connector and the adapter cooperate to define a second installation space. The fixing nut and the tuning nut are both screwed to the guide shaft. The tuning nut adjusts the compression or combined stiffness of the disc spring and the linear spring by adjusting the degree of tightening. The fixing nut fixes the spatial position of the guide shaft and the compression of the disc spring and the linear spring by tightening, thus fixing the quasi-zero stiffness characteristics of the system. The linear spring is located in the first mounting space and is clamped between the adapter and the guide shaft, while the disc spring is located in the second mounting space and is clamped between the guide shaft and the connector.

[0005] In an optional embodiment, the guide shaft includes a central shaft body and a limiting protrusion, the limiting protrusion being fixed to the outer peripheral surface of the central shaft body, and the limiting protrusion having a limiting surface facing the adapter. One end of the linear spring contacts the adapter, and the other end of the linear spring contacts the limiting surface; the fixing nut is located on the side of the adapter away from the limiting surface.

[0006] In an optional embodiment, the quasi-zero stiffness connection mechanism further includes a limiting block connected to the adapter, the limiting block being used to contact the limiting surface to limit the compression displacement of the linear spring.

[0007] In an optional embodiment, the connector includes a connecting cylinder and a support plate. The support plate is provided with an assembly through hole. The support plate is fixed to the connecting cylinder. The guide shaft passes through the assembly through hole. The tuning nut is located on the side of the support plate away from the fixing nut. The connecting cylinder and the adapter are slidably fitted together.

[0008] In an optional embodiment, the adapter includes an adapter plate and an adapter cylinder, the adapter plate and the adapter cylinder are fixedly connected, and the linear spring is located inside the adapter cylinder; the connecting cylinder is sleeved outside the adapter cylinder, and the connecting cylinder and the adapter cylinder are slidably connected. The disc spring is clamped between the adapter cylinder and the support plate.

[0009] In an optional embodiment, the end face of the adapter cylinder away from the adapter plate is provided with an annular limiting groove, and the disc spring is assembled in the annular limiting groove.

[0010] In an optional embodiment, the inner peripheral wall of the connecting cylinder is provided with a limiting step, which is used to contact the end face of the adapter cylinder to limit the compression displacement of the disc spring.

[0011] In an optional embodiment, there are multiple disc springs, which are stacked, paired, or combined, and an equalizing plate is provided between adjacent disc springs.

[0012] In an optional embodiment, the height-to-thickness ratio of the disc spring is set to be greater than [missing information]. .

[0013] In an optional embodiment, the robotic arm connection mechanism includes a connecting plate, a locking screw, and an anti-detachment washer; the connecting plate is provided with a positioning through hole, and the anti-detachment washer is fixed on the connecting plate; the locking screw is provided with an anti-detachment protrusion, and the locking screw passes through the anti-detachment washer and is inserted into the positioning through hole; the anti-detachment washer is used to contact the anti-detachment protrusion to prevent the locking screw from exiting the positioning through hole.

[0014] The beneficial effects of the embodiments of the present invention include, for example: In summary, the pre-tensioned quasi-zero stiffness connection device for surgical robots provided in this embodiment, when applied to surgical robots, can connect the robotic arm and power unit of the surgical robot. This achieves vibration isolation between the robotic arm and the power unit, improving operational reliability. Specifically, according to vibration theory, a frequency ratio (i.e., the ratio of the excitation frequency to the natural frequency) greater than... Only then can it achieve vibration isolation, and since the excitation frequency of the power unit is generally high, the natural frequency of the structure should be less than that of the power unit. A vibration isolation effect requires an excitation frequency that is several times higher.

[0015] In existing technologies, reducing the natural frequency involves either reducing stiffness or increasing mass. However, reducing stiffness leads to structural instability, while increasing mass is limited by installation space. In this embodiment, a disc spring with negative stiffness is selected, while a linear spring provides positive stiffness. Through reasonable parameter design, the negative stiffness of the disc spring and the positive stiffness of the linear spring cancel each other out, forming a quasi-zero stiffness range. By rotating the fixing nut and tuning nut, the combined stiffness of the linear spring and disc spring is adjusted and fixed, thereby regulating the preload applied to the device by both, canceling out the first positive stiffness range, and thus entering the quasi-zero stiffness range. In this range (i.e., the working range), displacement increases while the load remains essentially unchanged; therefore, almost no dynamic load acts on the robotic arm. Compared to traditional linear vibration isolation systems, the quasi-zero stiffness system has an extremely low natural frequency. At the same excitation frequency, the frequency ratio (excitation frequency / natural frequency) is much greater than that of a linear vibration isolator, making it easier to enter the vibration isolation zone. At the same time, the preload applied by the linear spring and disc spring can significantly increase the upper limit of the load-bearing capacity, greatly improving the static load-bearing capacity. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the pre-tensioned quasi-zero stiffness connection device for the surgical robot in this embodiment; Figure 2 This is a schematic diagram of the robotic arm connection mechanism in this embodiment; Figure 3 This is a schematic diagram of the quasi-zero stiffness connection mechanism in this embodiment; Figure 4 This is a schematic diagram of the adapter in this embodiment; Figure 5 This is a schematic diagram of the guide shaft in this embodiment; Figure 6 This is a schematic diagram of the connector in this embodiment; Figure 7 This is a schematic diagram of the disc spring in this embodiment; Figure 8 This is a schematic diagram of the disc spring stacking assembly in this embodiment; Figure 9 This is a schematic diagram of the disc spring mating assembly in this embodiment; Figure 10 This is a schematic diagram of the disc spring composite assembly in this embodiment; Figure 11This is a schematic diagram illustrating the mechanical principle of the pre-tensioned quasi-zero stiffness connection device for the surgical robot in this embodiment.

[0018] icon: 100 - Robotic arm connection mechanism; 110 - Connecting plate; 111 - Positioning groove; 112 - Positioning through hole; 120 - Locking screw; 130 - Anti-detachment washer; 200 - Quasi-zero stiffness connection mechanism; 201 - First installation space; 202 - Second installation space; 210 - Adapter; 211 - Adapter plate; 2111 - First plate surface; 2112 - Second plate surface; 2113 - Clearance groove; 2114 - First guide hole; 212 - Adapter cylinder; 2121 - Annular limiting groove; 220 - Guide shaft; 221 - Central shaft; 222 - Limiting protrusion; 2221 - Limiting surface; 23 0-Connector; 231-Connecting cylinder; 232-Support plate; 2321-Second guide hole; 233-Limiting step; 234-First cavity; 235-Second cavity; 240-Fixing nut; 250-Tuning nut; 260-Linear spring; 270-Disc spring; 271-Reduced end; 272-Open end; 273-Outer conical surface; 274-Inner conical surface; 280-Limiting block; 290-Fixing screw; 300-Equalizing plate. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0023] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0024] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0025] To reduce the interference of vibration on the robotic arm, improve surgical accuracy, and reduce the probability of system lock-up failure, existing surgical robots have adopted measures to reduce stiffness or increase mass. However, reducing stiffness leads to structural instability, while increasing mass is limited by installation space, and both have corresponding drawbacks.

[0026] In view of this, the designers have provided a pre-tensioned quasi-zero stiffness connection device for surgical robots, which can improve the vibration isolation effect of the device without reducing structural stiffness or increasing volume, thereby reducing the interference of vibration on the robotic arm.

[0027] Please refer to Figures 1-11 This embodiment provides a pre-tensioned quasi-zero stiffness connection device for a surgical robot, comprising: Robotic arm connecting mechanism 100 and quasi-zero stiffness connecting mechanism 200; The quasi-zero stiffness connection mechanism 200 includes an adapter 210, a guide shaft 220, a connector 230, a fixing nut 240, a tuning nut 250, a linear spring 260, and a disc spring 270. The adapter 210 is connected to the robotic arm connection mechanism 100. The guide shaft 220 is slidably connected to the adapter 210, and the two cooperate to define a first installation space 201. The connector 230 is slidably connected to the guide shaft 220, and the connector 230 cooperates with the adapter 210 to define a second installation space 202. The fixing nut 240 and the tuning nut 250 are both screwed to the guide shaft 220. The tuning nut adjusts the compression or combined stiffness (combined stiffness, i.e., quasi-zero stiffness) of the disc spring and the linear spring by adjusting the degree of tightening. The fixing nut fixes the spatial position of the guide shaft and the compression of the disc spring and the linear spring by tightening, i.e., fixes the quasi-zero stiffness characteristics of the system. The linear spring 260 is located in the first mounting space 201 and is clamped between the adapter 210 and the guide shaft 220, while the disc spring 270 is located in the second mounting space 202 and is clamped between the guide shaft 220 and the connector 230.

[0028] As described above, the pre-tensioned quasi-zero stiffness connection device for surgical robots provided in this embodiment operates as follows: The pre-tensioned quasi-zero stiffness connection device of the surgical robot has quasi-zero stiffness characteristics through pre-tensioning. It is then connected to the surgical robot arm through the robotic arm connection mechanism. At the same time, the power unit is installed below the connection. The force load generated by the power unit when it is working is isolated after passing through the pre-tensioned quasi-zero stiffness connection device of the surgical robot, which greatly reduces the force feedback to the robotic arm and avoids the robotic arm shaking and locking.

[0029] Specifically, according to vibration theory, the frequency ratio (i.e., the ratio of the excitation frequency to the natural frequency) is greater than... Only then can it achieve vibration isolation, and since the excitation frequency of the power unit is generally high, the natural frequency of the structure should be less than that of the power unit. A vibration isolation effect requires an excitation frequency that is several times higher than the normal frequency. In existing technologies, reducing the natural frequency involves either reducing stiffness or increasing mass. However, reducing stiffness leads to structural instability, while increasing mass is limited by installation space. In this embodiment, a disc spring 270 with negative stiffness mechanical characteristics is selected, while a linear spring 260 provides positive stiffness. Through reasonable parameter design, the negative stiffness of the disc spring 270 and the positive stiffness of the linear spring 260 cancel each other out, forming a quasi-zero stiffness range. By rotating the fixing nut 240 and the tuning nut 250, the compression of the linear spring 260 and the disc spring 270 is adjusted respectively, thereby adjusting the preload applied to the device by both, canceling out the first positive stiffness range and entering the quasi-zero stiffness range. In this range, displacement increases while the load remains essentially unchanged; therefore, almost no dynamic load acts on the robotic arm, effectively improving vibration isolation performance. Compared to traditional linear vibration isolation systems, quasi-zero stiffness systems have extremely low natural frequencies. At the same excitation frequency, the frequency ratio (excitation frequency / natural frequency) is much greater than that of linear isolators, making it easier to enter the vibration isolation zone. Meanwhile, the preload applied by the linear spring 260 and disc spring 270 can significantly increase the upper limit of the load and greatly improve the static load capacity.

[0030] It should be noted that the tuning nut adjusts the compression of the disc spring and the linear spring by adjusting the degree of tightening, the tuning nut adjusts the combined stiffness of the disc spring and the linear spring by adjusting the degree of tightening, and the tuning nut adjusts the near-zero stiffness of the disc spring and the linear spring by adjusting the degree of tightening. All three expressions have the same meaning.

[0031] The following embodiments illustrate the details of the pre-tensioned quasi-zero stiffness connection device for surgical robots of this application by way of example.

[0032] Please refer to Figures 1-11 In this embodiment, optionally, the pre-tensioned quasi-zero stiffness connection device for the surgical robot includes a robotic arm connection mechanism 100 and a quasi-zero stiffness connection mechanism 200. The robotic arm connection mechanism 100 is used for detachable connection with the robot's robotic arm, and the quasi-zero stiffness connection mechanism 200 is connected to the robotic arm connection mechanism 100 and is used for connecting the power unit. Thus, through the design of the connection device, vibration isolation between the robotic arm and the power unit can be achieved, improving operational reliability.

[0033] Please refer to Figures 1-2 In this embodiment, optionally, the robotic arm connection mechanism 100 includes a connecting plate 110, a locking screw 120, and an anti-detachment washer 130. A positioning groove 111 is provided on one side of the connecting plate 110, and a positioning through hole 112 is provided on the connecting plate 110. The positioning through hole 112 can be a circular hole, with one end penetrating the bottom wall of the positioning groove 111 and the other end penetrating the side of the connecting plate 110 away from the positioning groove 111. That is, the positioning through hole 112 connects to the positioning groove 111 at the bottom wall of the positioning groove 111. The anti-detachment washer 130 can be fixed to the connecting plate 110 by welding, and the anti-detachment washer 130 is located on the side of the positioning through hole 112 away from the positioning groove 111. The outer peripheral surface of the locking screw 120 is provided with an annular anti-loosening protrusion. The locking screw 120 passes through the anti-loosening washer 130 and is inserted into the positioning through hole 112. The anti-loosening protrusion is located on the side of the anti-loosening washer 130 near the positioning groove 111. With this design, the anti-loosening washer 130 is used to contact the anti-loosening protrusion to limit the locking screw 120 from exiting the positioning through hole 112 in the direction from the opening of the positioning groove 111 to the bottom wall of the groove.

[0034] It should be noted that there can be multiple positioning through holes 112, arranged in a circular pattern. Each positioning through hole 112 can position one locking screw 120, and correspondingly, an anti-loosening washer 130 can be configured at each positioning through hole 112, with each anti-loosening washer 130 cooperating with the corresponding locking screw 120. Connecting the robotic arm with multiple locking screws 120 improves the connection's firmness. The robotic arm can be inserted into the positioning groove 111, improving the structural compactness.

[0035] Please refer to Figures 1-10In this embodiment, the optional quasi-zero stiffness connection mechanism 200 includes an adapter 210, a guide shaft 220, a connector 230, a fixing nut 240, a tuning nut 250, a linear spring 260, a disc spring 270, a limiting block 280, and a fixing screw 290. The adapter 210 can be fixedly connected to the connecting plate 110 via screws or other structural components. Obviously, the adapter 210 can also be fixedly connected to the connecting plate 110 in other ways. The guide shaft 220 is slidably connected to the adapter 210 along a preset direction. The connector 230 is slidably connected to the guide shaft 220 along a preset direction. The fixing nut 240 and the tuning nut 250 are both screwed to the guide shaft 220, and are arranged at intervals. A linear spring 260 is clamped between a guide shaft 220 and an adapter 210, providing elastic force extending in a preset direction. A disc spring 270 is clamped between an adapter 210 and a connector 230, also providing elastic force extending in a preset direction. A limiting block 280 is fixed to the adapter 210 by a fixing screw 290. The limiting block 280 can contact the guide shaft 220 to limit the compressed length of the linear spring 260, preventing over-compression and damage to the linear spring 260.

[0036] Please refer to Figure 4 Optionally, the adapter 210 includes an integrally structured adapter plate 211 and adapter cylinder 212. The adapter plate 211 can be fixedly connected to the connecting disc 110 by screws or other structural components. The adapter plate 211 has a first plate surface 2111 and a second plate surface 2112 opposite to each other in a preset direction. The first plate surface 2111 is provided with a clearance groove 2113, and the bottom wall of the clearance groove 2113 is provided with a first guide hole 2114. The port of the first guide hole 2114 is located on the second plate surface 2112. The clearance groove 2113 and the first guide hole 2114 can be coaxially arranged, which is beneficial for processing. The adapter cylinder 212 is located on the second plate surface 2112. The adapter cylinder 212 can be a cylindrical cylinder, and the adapter cylinder 212 is coaxially arranged with the first guide hole 2114. Meanwhile, an annular limiting groove 2121 is provided on the end face of the adapter cylinder 212 away from the adapter plate 211, and one side of the annular limiting groove 2121 is connected to the cylinder cavity of the adapter cylinder 212.

[0037] Please refer to Figure 5Optionally, the guide shaft 220 can be configured as a stepped shaft. The guide shaft 220 includes an integral central shaft body 221 and a limiting protrusion 222. The central shaft body 221 can be cylindrical, and the limiting protrusion 222 can be an annular structure fitted around the central shaft body 221; both are coaxially arranged. The limiting protrusion 222 divides the central shaft body 221 into a first shaft segment and a second shaft segment. The outer circumferential surface of the first shaft segment is provided with external threads. The first shaft segment passes through the first guide hole 2114 and extends into the clearance groove 2113. The fixing nut 240 is screwed into the external threads of the first shaft segment. The outer circumferential surface of the second shaft segment is provided with external threads, and the tuning nut 250 is screwed into the external threads of the second shaft segment.

[0038] Please refer to Figure 6 Optionally, the connector 230 includes an integral connecting cylinder 231 and a support plate 232. The connecting cylinder 231 can be a cylindrical cylinder, and the support plate 232 is located inside the connecting cylinder 231 and is coaxially arranged with the connecting cylinder 231. A second guide hole 2321 is provided at the middle position of the support plate 232. The second guide hole 2321 can be a circular hole and is coaxially arranged with the connecting cylinder 231. The support plate 232 divides the cavity of the connecting cylinder 231 into a first cavity 234 and a second cavity 235. A second shaft segment passes through the first cavity 234 and the second guide hole 2321 and extends into the second cavity 235. The tuning nut 250 is located inside the second cavity 235. The connecting cylinder 231 can be connected to the power device by bolts or other structural components.

[0039] Furthermore, a limiting step 233 is provided on the inner peripheral wall of the connecting cylinder 231 corresponding to the first cavity 234. The limiting step 233 protrudes inward relative to the inner peripheral wall. The limiting step 233 can be an annular step and is coaxially arranged with the connecting cylinder 231.

[0040] The specific assembly structure of the quasi-zero stiffness connection mechanism 200 provided in this embodiment is as follows: A guide shaft 220 passes through the adapter cylinder 212. The first section of the guide shaft 220 passes through the first guide hole 2114 and extends into the clearance groove 2113. A fixing nut 240 is located in the clearance groove 2113 and screwed onto the first section. The limiting protrusion 222 of the guide shaft 220 cooperates with the adapter plate 211 to define a first installation space 201. A limiting block 280 is fixed to the second plate surface 2112 of the adapter plate 211 by fixing screws 290 and is located within the first installation space 201. Simultaneously, a linear spring 260 is sleeved around the limiting block 280 and is located within the first installation space 201. One end of the linear spring 260 contacts the second plate surface 2112, and the other end contacts the limiting protrusion 222 near the limiting surface 2221 of the adapter plate 211. When the linear spring 260 is compressed, the limiting surface 2221 gradually approaches the limiting block 280, and the two can come into contact, thereby limiting the compression of the linear spring 260 and preventing the linear spring 260 from being over-compressed and damaged. The connecting cylinder 231 of the connector 230 is sleeved on the outside of the adapter cylinder 212, and the two are slidably connected in a preset direction. The support plate 232 and the adapter cylinder 212 define a second mounting space 202. The second shaft segment of the guide shaft 220 passes through the first cavity 234 and the second guide hole 2321 on the support plate 232 and extends into the second cavity 235. The tuning nut 250 is screwed to the second shaft segment and is located in the second cavity 235. The disc spring 270 is sleeved on the outside of the second shaft segment and is clamped between the annular limiting groove and the support plate.

[0041] The preset direction is consistent with the axial direction of the guide shaft 220.

[0042] It should be understood that during the assembly of the pre-tightened quasi-zero stiffness connection device, the sequence of action of the tuning nut and the fixing nut is as follows: first, the tuning nut is screwed to the designed position, and then the fixing nut is used to fix the entire structure to maintain the designed quasi-zero stiffness mechanical characteristics. When the tuning nut 250 is rotated, the connecting piece 230 can slide relative to the adapter cylinder 212 in a preset direction. When the connecting piece 230 moves close to the adapter cylinder 212, the end face of the adapter cylinder 212 can contact the end face of the limiting step 233, thereby controlling the compression of the disc spring 270 and preventing the disc spring 270 from being over-compressed and damaged.

[0043] Please refer to Figures 7-10 Optionally, the disc spring 270 has a constricted end 271 and an open end 272. The distance between the constricted end 271 and the open end 272 is h0, representing the height of the disc spring 270. The distance between the outer conical surface 273 and the inner conical surface 274 of the disc spring 270 is t, where t represents the thickness of the disc spring 270. In this embodiment, the ratio of the height to the thickness of the disc spring 270 is greater than... This gives the disc spring 270 negative stiffness mechanical properties.

[0044] Specifically, the following formulas (1) and (2) can be used to illustrate the relationship between the load and displacement of disc spring 270:

[0045] (2) Where F represents the load on disc spring 270; f represents the displacement compression; μ represents Poisson's ratio; D represents the outer diameter of disc spring 270; E represents the elastic modulus; S represents the thickness of disc spring 270; C represents the ratio of the inner and outer diameters of disc spring 270; and h0 represents the height of disc spring 270.

[0046] According to the above formula, different mechanical properties can be obtained by selecting the appropriate disc spring 270. Therefore, in this embodiment, the disc spring 270 with a height-to-thickness ratio greater than [missing value] is selected. The disc spring 270 possesses negative stiffness mechanical characteristics, while the linear spring 260 provides positive stiffness. Through reasonable parameter design, the positive and negative stiffnesses of the disc spring 270 and the linear spring 260 cancel each other out. By preloading, a quasi-zero stiffness range is formed. Within this range, as displacement increases, the load remains essentially unchanged, with almost no load acting on the robotic arm. Compared to traditional linear vibration isolation systems, the quasi-zero stiffness system, due to its extremely low natural frequency, has a much higher frequency ratio (excitation frequency / natural frequency) at the same excitation frequency, making it easier to enter the isolation zone. Furthermore, preloading can significantly increase the upper limit of load capacity, greatly improving the static load-bearing capacity.

[0047] It should be understood that there can be one or more disc springs 270. When there are multiple disc springs 270, the multiple disc springs 270 are stacked and arranged, and an equalizing plate 300 is provided between adjacent disc springs 270. The disc springs 270 are in contact with the equalizing plate, the contact area is large, it is not easy to generate torsion, and it can stably provide elastic force extending in the preset direction.

[0048] For example, in this embodiment, there are two disc springs 270, and a pressure equalizing plate 300 is provided between the two disc springs 270. The constricted ends 271 of both disc springs 270 are in contact with the pressure equalizing plate, the open end 272 of one disc spring 270 is in contact with the annular limiting groove 2121, and the open end 272 of the other disc spring 270 is in contact with the support plate 232. Alternatively, multiple disc springs 270 can be stacked. In other words, the number and arrangement of the disc springs 270 can be designed as needed.

[0049] In other embodiments, optionally, the adapter 210 and the robotic arm connection mechanism 100 can be configured as an integral structure, that is, the adapter plate 211 and the connecting plate 110 are integrated into one piece, and the locking screw 120 is directly assembled with the adapter plate 211. The robotic arm is positioned by the adapter plate 211 and locked by the locking screw 120.

[0050] The pre-tensioned quasi-zero stiffness connection device for surgical robots provided in this embodiment has at least the following advantages: 1. Compared with traditional surgical robot connection devices, the embodiments of this application can achieve near-zero stiffness, thereby greatly improving vibration isolation efficiency, effectively suppressing vibration transmission, and reducing the probability of system lock-up failure; 2. Expand the effective vibration isolation frequency band, implement ultra-low frequency vibration isolation, and avoid vibration impact during equipment start-up and shutdown; 3. By using pre-tightening, the poor robustness of quasi-zero stiffness vibration isolators at the equilibrium position is addressed, the quasi-zero stiffness range is increased, and the stability at the equilibrium position is improved; 4. By adjusting and fixing the stiffness characteristics of the system with tuning nuts and fixing nuts, the preload is equivalent to adding an initial load to the system, which can significantly increase the upper limit of the load and greatly improve the static load capacity. 5. Precise control of the pre-tightened quasi-zero stiffness point: the working point is locked by pre-compression, and the vibration isolation response time is basically zero; 6. The pre-tensioned quasi-zero stiffness connection device of this surgical robot does not require the introduction of electromagnetic control, adopts a purely mechanical structure, and does not need to consider EMC-related issues.

[0051] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A pre-tensioned quasi-zero stiffness connection device for a surgical robot, characterized in that, include: Robotic arm connection mechanism (100) and quasi-zero stiffness connection mechanism (200); The quasi-zero stiffness connection mechanism (200) includes an adapter (210), a guide shaft (220), a connector (230), a fixing nut (240), a tuning nut (250), a linear spring (260), and a disc spring (270); the adapter (210) is connected to the robotic arm connection mechanism (100); the guide shaft (220) is slidably connected to the adapter (210), and the two cooperate to define a first installation space (201); the connector (230) is slidably connected to the guide shaft (220). The connecting piece (230) and the adapter piece (210) cooperate to define a second installation space (202); the fixing nut (240) and the tuning nut (250) are both screwed to the guide shaft (220). The tuning nut (250) adjusts the compression or combined stiffness of the disc spring (270) and the linear spring (260) by the degree of tightening. The fixing nut (240) fixes the spatial position of the guide shaft (220) and the compression of the disc spring (270) and the linear spring (260) by tightening. The linear spring (260) is located in the first mounting space (201) and is clamped between the adapter (210) and the guide shaft (220), and the disc spring (270) is located in the second mounting space (202) and is clamped between the guide shaft (220) and the connector (230).

2. The pre-tensioned quasi-zero stiffness connection device for surgical robots according to claim 1, characterized in that: The guide shaft (220) includes a central shaft body (221) and a limiting protrusion (222). The limiting protrusion (222) is fixed to the outer peripheral surface of the central shaft body (221), and the limiting protrusion (222) has a limiting surface (2221) facing the adapter (210). One end of the linear spring (260) is in contact with the adapter (210), and the other end of the linear spring (260) is in contact with the limiting surface (2221); the fixing nut (240) is located on the side of the adapter (210) away from the limiting surface (2221).

3. The pre-tensioned quasi-zero stiffness connection device for surgical robots according to claim 2, characterized in that: The quasi-zero stiffness connection mechanism (200) further includes a limiting block (280) connected to the adapter (210). The limiting block (280) is used to contact the limiting surface (2221) to limit the compression displacement of the linear spring (260).

4. The pre-tensioned quasi-zero stiffness connection device for surgical robots according to claim 1, characterized in that: The connector (230) includes a connecting cylinder (231) and a support plate (232). The support plate (232) is provided with an assembly through hole. The support plate (232) is fixed inside the connecting cylinder (231). The guide shaft (220) passes through the assembly through hole. The tuning nut (250) is located on the side of the support plate (232) away from the fixing nut (240). The connecting cylinder (231) and the adapter (210) are slidably fitted together.

5. The pre-tensioned quasi-zero stiffness connection device for surgical robots according to claim 4, characterized in that: The adapter (210) includes an adapter plate (211) and an adapter cylinder (212). The adapter plate (211) is fixedly connected to the adapter cylinder (212), and the linear spring (260) is located inside the adapter cylinder (212). The connecting cylinder (231) is sleeved on the outside of the adapter cylinder (212), and the connecting cylinder (231) is slidably connected to the adapter cylinder (212). The disc spring (270) is held between the adapter cylinder (212) and the support plate (232).

6. The pre-tensioned quasi-zero stiffness connection device for surgical robots according to claim 5, characterized in that: The end face of the adapter cylinder (212) away from the adapter plate (211) is provided with an annular limiting groove (2121), and the disc spring (270) is assembled in the annular limiting groove (2121).

7. The pre-tensioned quasi-zero stiffness connection device for surgical robots according to claim 5, characterized in that: The inner circumferential wall of the connecting cylinder (231) is provided with a limiting step (233), which is used to contact the end face of the adapter cylinder (212) to limit the compression displacement of the disc spring (270).

8. The pre-tensioned quasi-zero stiffness connection device for surgical robots according to any one of claims 1-7, characterized in that: The number of disc springs (270) is multiple, and the multiple disc springs (270) are stacked, paired, or combined. A pressure equalizing plate (300) is provided between adjacent disc springs (270).

9. The pre-tensioned quasi-zero stiffness connection device for surgical robots according to any one of claims 1-7, characterized in that: The height-to-thickness ratio of the disc spring (270) is set to be greater than 1. .

10. The pre-tensioned quasi-zero stiffness connection device for surgical robots according to any one of claims 1-7, characterized in that: The robotic arm connection mechanism (100) includes a connecting plate (110), a locking screw (120), and an anti-detachment washer (130); the connecting plate (110) is provided with a positioning through hole (112), and the anti-detachment washer (130) is fixed on the connecting plate (110); the locking screw (120) is provided with an anti-detachment protrusion, and the locking screw (120) passes through the anti-detachment washer (130) and is inserted into the positioning through hole (112); the anti-detachment washer (130) is used to contact the anti-detachment protrusion to restrict the locking screw (120) from exiting the positioning through hole (112).

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