A test hydraulic system

Abstract

This application discloses a test hydraulic system, including a gantry and Z-axis, X-axis, and Y-axis loading mechanisms mounted on the gantry. The loading mechanism, which loads along the pedaling direction of a legged robot, includes a support frame, a loading cylinder, a stroke reduction component, and a hydraulic control module. The loading cylinder is fixedly mounted on the support frame and connected to the hydraulic control module, which provides back pressure when the piston rod of the loading cylinder extends. The stroke reduction component is mounted on the support frame and connected to the piston rod of the loading cylinder via a traction end. The stroke reduction component is used to reduce the stroke of the legged robot according to a set ratio to traction the piston rod of the loading cylinder. The advantages of this application are: by using a stroke reduction component for transmission, instead of direct pedaling action on the loading cylinder, the stability problem of the piston rod caused by the long stroke of the loading cylinder is avoided, and the size of the support frame is effectively reduced, thus lowering costs.

Description

Technical Field

[0001] This application relates to the field of hydraulic technology, and in particular to a test hydraulic system. Background Technology

[0002] Current performance testing of legged robots, whether for the whole machine or a single leg, typically employs treadmill-like testing devices. These devices generally lack the loading capability for foot contact testing; even when loading is applied, it's a passive, uncontrollable loading process. Furthermore, the leg cannot interact with the main unit, making repeated pedaling tests impossible and failing to meet the performance testing requirements for multiple reciprocating loads on a single leg. Some technologies use direct hydraulic cylinder thrust, where the pedaling action directly impacts the cylinder. Due to the long pedaling stroke of the robotic leg, this results in a long cylinder stroke. Piston stability issues necessitate a larger piston area, increasing the minimum test pedaling force. Simultaneously, the pedaling support frame becomes very long, leading to an extremely large testing frame. Summary of the Invention

[0003] One objective of this application is to provide a test hydraulic system that can solve at least one of the defects in the aforementioned background art.

[0004] To achieve at least one of the above objectives, the technical solution adopted in this application is as follows: a test hydraulic system, including a gantry frame and a Z-axis loading mechanism, an X-axis loading mechanism, and a Y-axis loading mechanism mounted on the gantry frame; the Z-axis loading mechanism is used to mount a legged robot and perform vertical loading; the X-axis loading mechanism and the Y-axis loading mechanism are used to perform horizontal loading on the legged robot; wherein, the loading mechanism that performs loading along the main pedaling direction of the legged robot includes a support frame, a loading cylinder, a stroke reduction component, and a hydraulic control module; the loading cylinder is fixedly mounted on the support frame and connected to the hydraulic control module, the hydraulic control module being adapted to provide back pressure when the piston rod of the loading cylinder extends; the stroke reduction component is mounted on the support frame and connected to the piston rod of the loading cylinder through a traction end, the bearing end of the stroke reduction component being used to cooperate with the pedaling motion of the legged robot, the stroke reduction component being adapted to perform synchronous pedaling with the legged robot, and to traction the piston rod of the loading cylinder after reducing the stroke of the legged robot according to a set ratio.

[0005] Preferably, the stroke reduction assembly includes a first lead screw and a second lead screw; the first lead screw and the second lead screw are arranged in parallel and rotatably mounted on the support frame; a slider that slides and engages with the support frame is mounted on the first lead screw, and the slider is connected to the piston rod of the loading cylinder; an output platform that slides and engages with the support frame is mounted on the second lead screw, and the output platform is used to connect to another loading mechanism or to support a legged robot; the first lead screw and the second lead screw are connected by a transmission assembly; the second lead screw is adapted to convert the pedaling motion of the legged robot into rotational motion, and the first lead screw is adapted to convert the rotational motion into linear traction motion on the loading cylinder; the extension stroke of the loading cylinder is adjusted by the reduction ratio of the transmission assembly and / or the lead ratio of the first lead screw and the second lead screw.

[0006] Preferably, the stroke reduction component further includes a rotating device, which is fixedly mounted on the support frame and connected to one of the lead screws via an output end; the rotating device is adapted to continuously output a fixed torque when the legged robot performs a pedaling action to overcome the frictional force required for the rotation of the first lead screw and the second lead screw; the rotating device is adapted to drive the first lead screw and the second lead screw to reset the output platform and the slider after the legged robot completes the pedaling action.

[0007] Preferably, the X-axis loading mechanism and the Y-axis loading mechanism have the same structure, the Y-axis loading mechanism is installed above the X-axis loading mechanism and supports the legged robot through the bearing end; the loading direction of the X-axis loading mechanism is along the main pedaling action direction of the legged robot.

[0008] Preferably, the hydraulic control module includes an oil replenishment circuit, an overflow valve assembly, and a return circuit; the first end of the oil replenishment circuit is connected to the hydraulic pressure source and the oil tank, and the second end of the oil replenishment circuit is connected to the rodless chamber and the rod chamber of the loading cylinder; the overflow valve assembly is connected between the rod chamber of the loading cylinder and the oil tank; one end of the return circuit is connected to the rod chamber and the rodless chamber of the loading cylinder, and the other end of the return circuit is connected to the hydraulic pressure source and the oil tank; the oil replenishment circuit is adapted to simultaneously supply oil to the rod chamber and the rodless chamber of the loading cylinder during the pedaling test of the legged robot, at which time the overflow valve assembly is adapted to provide back pressure to the rod chamber of the loading cylinder to simulate pedaling resistance; after the legged robot completes the pedaling action, the oil replenishment circuit is adapted to connect both the rod chamber and the rodless chamber of the loading cylinder to the oil tank, so that the rotating device drives the lead screw to reset the loading cylinder; the return circuit is adapted to drive the loading cylinder to reset when the rotating device fails.

[0009] Preferably, the oil replenishment circuit includes a first control valve, a second directional valve, a first hydraulically controlled check valve, a check valve, and a second control valve; the rodless chamber and the rod chamber of the loading cylinder are respectively connected to one side of the first control valve through the first hydraulically controlled check valve and the check valve, and the other side of the first control valve is connected to a hydraulic pressure source to form an oil supply branch; the rod chamber of the loading cylinder is connected to the oil tank in sequence through the second control valve and the overflow valve group to form a return oil branch; the control end of the first hydraulically controlled check valve is connected to the hydraulic pressure source through the second directional valve; when the legged robot performs pedaling... When the robot pedals, the first control valve opens the oil supply branch, allowing the oil pressure source to simultaneously supply oil to both the rod-side and rodless-side chambers of the loading cylinder. Simultaneously, the second control valve opens the return oil branch and provides return oil back pressure to the rod-side chamber of the loading cylinder through the overflow valve assembly. After the legged robot completes the pedaling motion, the first control valve closes, and the second directional valve opens, connecting the rodless-side chamber of the loading cylinder to the oil tank via the first hydraulic check valve. At the same time, the second control valve remains open and controls the overflow valve assembly to adjust the return oil back pressure to zero.

[0010] Preferably, the retraction circuit includes a third directional valve, two second hydraulically controlled check valves, and two throttle valves; a single second hydraulically controlled check valve is connected to the corresponding throttle valve to form a connecting branch; the rod-side and rodless-side chambers of the loading cylinder are both connected to one side port of the third directional valve through the corresponding connecting branch, and the other side port of the third directional valve is connected to the hydraulic pressure source and the oil tank respectively; the third directional valve is adapted to remain closed when the legged robot is pedaling and the rotating device is working normally; when the legged robot completes pedaling and the rotating device malfunctions, the third directional valve is opened, so that the hydraulic pressure source supplies oil to the rod-side chamber of the loading cylinder, while the oil in the rodless-side chamber of the loading cylinder flows back to the oil tank.

[0011] Preferably, the hydraulic control module further includes a pressure reducing valve, a first directional valve, and an accumulator; the hydraulic pressure source is connected to the input end of the oil supply branch through the pressure reducing valve and the first directional valve connected in sequence. The pressure reducing valve is used to reduce the oil supply pressure of the hydraulic pressure source to compensate for the friction generated by the loading cylinder during the piston rod extension process. The first directional valve is used to control the working cut-in of the hydraulic pressure source; the accumulator is connected in parallel to the input end of the oil supply branch as an auxiliary oil source.

[0012] Preferably, the test hydraulic system further includes a tilt simulation mechanism, which is located below the X-axis loading mechanism and the Y-axis loading mechanism and connected to the loading mechanism located below the stacked structure. The tilt simulation mechanism includes four drive cylinders and a control oil circuit. The four drive cylinders are arranged in a 2×2 array, and the control oil circuit is connected to the four drive cylinders. The control oil circuit controls the four drive cylinders to perform not exactly the same extension and retraction movements, so that the overall structure formed by the X-axis loading mechanism and the Y-axis loading mechanism can simulate tilting in different directions and to different degrees.

[0013] Preferably, the control oil circuit has four components, each controlling a corresponding drive cylinder. Each control oil circuit includes a third hydraulically controlled check valve, a proportional valve, and a third directional valve. The rod-side and rodless-side chambers of the drive cylinder are connected to one port of the proportional valve via the third hydraulically controlled check valve. The other port of the proportional valve is connected to a hydraulic pressure source and an oil tank. One port of the third directional valve is connected to the hydraulic pressure source and the oil tank, while the other port is connected to two third hydraulically controlled check valves. The proportional valve is adapted to control the hydraulic pressure source to supply oil to the rodless or rod-side chamber of the drive cylinder. The third directional valve is adapted to control the third hydraulically controlled check valve connected to the non-supply chamber of the drive cylinder to open, allowing the oil in the non-supply chamber to flow back to the oil tank.

[0014] Compared with the prior art, the beneficial effects of this application are as follows:

[0015] (1) The technical solution of this application can realize active loading or variable loading, and apply accurate load force at the same time, load from multiple dimensions, thereby simulating the friction force during pedaling, and all pedaling force data can be recorded. At the same time, after pedaling, the loading mechanism can accurately return to its original position. The loading mechanism can effectively interact with the legs of the legged robot to realize repeated identical pedaling tests and verify the pedaling effect of the legged robot.

[0016] (2) The screw drive is used instead of the pedal directly acting on the loading cylinder, thus avoiding the piston rod stability problem caused by the long stroke of the loading cylinder, and also effectively reducing the volume of the support frame and reducing costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall architecture of this application.

[0018] Figure 2 This is a schematic diagram of the superimposed installation structure of the X-axis loading mechanism and the Y-axis loading mechanism in this application.

[0019] Figure 3 This is a schematic diagram of the X-axis loading mechanism in this application.

[0020] Figure 4 This is a simplified schematic diagram illustrating the working principle of the X-axis loading mechanism in this application during the testing process.

[0021] Figure 5 This is a schematic diagram of the hydraulic control module in this application.

[0022] Figure 6 This is a schematic diagram of the hydraulic control structure of the tilting simulation mechanism in this application.

[0023] In the diagram: Z-axis loading mechanism 1, lifting device 2, X-axis loading mechanism 3, support frame 31, first lead screw 32, slider 33, loading cylinder 34, second lead screw 35, rotating device 36, first gear 371, second gear 372, pressure reducing valve 301, first reversing valve 302, first control valve 303, check valve 304, second control valve 305, first hydraulic check valve 306, second reversing valve 307, overflow valve group 308, accumulator 309, third reversing valve 310, second hydraulic check valve 311, throttle valve 312, Y-axis loading mechanism 4, output platform 5, mounting frame 6, gantry frame 7, tilting simulation mechanism 8, drive cylinder 81, third hydraulic check valve 82, proportional valve 83, third reversing valve 84. Detailed Implementation

[0024] The present application will now be further described in conjunction with specific embodiments. It should be noted that, in the description of this specification, the use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0025] In the description of this application, it should be noted that the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., which indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application 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 should not be construed as limiting the specific protection scope of this application.

[0026] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0027] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0029] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0030] One preferred embodiment of this application, such as Figures 1 to 3As shown, a test hydraulic system includes a gantry frame 7 and Z-axis loading mechanism 1, X-axis loading mechanism 3, Y-axis loading mechanism 4, and tilting simulation mechanism 8 mounted on the gantry frame 7. The Z-axis loading mechanism 1 is mounted on the top of the gantry frame 7 and connected to the legs of the legged robot to be tested via a mounting bracket 6. It should be noted that the pedaling test of the legged robot mainly tests its legs; therefore, it is not necessary to install the entire legged robot, only its legs need to be mounted on the Z-axis loading mechanism 1 for the pedaling test. Since only the legs of the legged robot are tested, the Z-axis loading mechanism 1 can actively load the legs of the legged robot to simulate its upper body weight, and also simulate the inertial load generated by the legs based on the upper body weight during the pedaling process.

[0031] The X-axis loading mechanism 3 and Y-axis loading mechanism 4 are located below the Z-axis loading mechanism 1 and are stacked vertically to form an overall structure for horizontal loading of the legged robot. The robot's feet can be movably mounted on the upper surface of this overall structure. Thus, the X-axis loading mechanism 3 can simulate the ground friction force exerted on the legged robot in the X-axis direction, and the Y-axis loading mechanism 4 can simulate the ground friction force exerted on the legged robot in the Y-axis direction. That is, during the legged robot's pedaling test, the X-axis loading mechanism 3 moves along the X-axis with the robot's legs, simulating the friction force applied by the ground along the X-axis, and the Y-axis loading mechanism 4 moves along the Y-axis with the robot's legs, simulating the friction force applied by the ground along the Y-axis, ensuring that the robot's legs can maintain their mounting position while performing the pedaling action. Compared to traditional methods, the technical solution of this application can achieve active or variable loading, simultaneously applying accurate load forces from multiple dimensions to simulate the friction force during pedaling, and all pedaling force data can be recorded. At the same time, after the pedaling is completed, the loading mechanism can accurately return to its original position. The loading mechanism can effectively interact with the legs of the legged robot to achieve repeated identical pedaling tests and verify the pedaling effect of the legged robot.

[0032] The horizontal pedaling motion of a legged robot can be decomposed into a primary motion direction and a secondary motion direction; the pedaling motion has a larger stroke in the primary motion direction. In the X-axis loading mechanism 3 and Y-axis loading mechanism 4, the loading mechanism that loads at least along the primary pedaling motion direction of the legged robot includes a support frame 31, a loading cylinder 34, a stroke reduction component, and a hydraulic control module. The loading cylinder 34 is fixedly installed on the support frame 31 and connected to the hydraulic control module. The piston rod of the loading cylinder 34 can extend with the pedaling motion of the legged robot. The hydraulic control module can provide back pressure when the piston rod of the loading cylinder 34 extends to simulate the friction force of the ground on the legged robot. The stroke reduction component is installed on the support frame 31 and connected to the piston rod of the loading cylinder 34 through a traction end. The bearing end of the stroke reduction component is used to cooperate with the pedaling motion of the legged robot. The stroke reduction component can pedal synchronously with the legged robot and reduce the stroke of the legged robot according to a set ratio to traction the piston rod of the loading cylinder 34. This application uses a speed reduction transmission method with a stroke reduction component instead of the traditional method of directly applying pedal to the loading cylinder 34. This can effectively avoid the piston rod stability problem caused by the long stroke of the loading cylinder 34 in the traditional method, and also effectively reduce the volume of the support frame 31 and reduce costs.

[0033] The tilting simulation mechanism 8 is installed at the bottom of the gantry 7 and is located below the overall structure in which the X-axis loading mechanism 3 and the Y-axis loading mechanism 4 are stacked. The drive end of the tilting simulation mechanism 8 is connected to the overall structure in which the X-axis loading mechanism 3 and the Y-axis loading mechanism 4 are stacked, so that the tilting simulation mechanism 8 can drive the overall structure in which the X-axis loading mechanism 3 and the Y-axis loading mechanism 4 are stacked to tilt to different degrees in different directions, so as to simulate the various complex road conditions faced by the legged robot in actual use.

[0034] It is important to know that, depending on the type of legged robot, the Z-axis loading mechanism 1, X-axis loading mechanism 3, and Y-axis loading mechanism 4 can apply different loads as needed. Meanwhile, the Z-axis loading mechanism 1 is installed on the top crossbeam of the gantry 7, and the crossbeam can be vertically adjusted by the lifting devices 2 installed on both sides to ensure that the height between the Z-axis loading mechanism 1 and the X-axis loading mechanism 3 and Y-axis loading mechanism 4 stacked together can accommodate different types of legged robots for testing.

[0035] In this embodiment, as Figure 2As shown, the superimposed arrangement of the X-axis loading mechanism 3 and the Y-axis loading mechanism 4 can be such that the X-axis loading mechanism 3 is on top, or the Y-axis loading mechanism 4 is on top. The main direction of the legged robot's pedaling motion can be along the X-axis or the Y-axis. For ease of subsequent description, in this embodiment, the Y-axis loading mechanism 4 is preferably positioned above the X-axis loading mechanism 3, and the main direction of the legged robot's pedaling motion is along the X-axis. Since the legged robot has a large stroke in the main pedaling direction, in this embodiment, a stroke reduction component can be set in the X-axis loading mechanism 3 to reduce the pedaling stroke. For the Y-axis loading mechanism 4, since the pedaling motion has a short stroke in the secondary direction, a traditional setting method can be used. However, in order to further reduce the installation space of the Y-axis loading mechanism 4 and improve the simulation accuracy, in this embodiment, the Y-axis loading mechanism 4 adopts the same structure as the X-axis loading mechanism 3, except that the total length of the Y-axis loading mechanism 4 is adaptively shortened and does not need to be the same length as the X-axis loading mechanism 3.

[0036] In this embodiment, there are various specific structures for the range reduction component that can achieve the above functions. For ease of understanding, a specific example will be used for detailed explanation below. Figure 3 and Figure 4 As shown, the stroke reduction assembly includes a first lead screw 32 and a second lead screw 35. The first lead screw 32 and the second lead screw 35 are arranged in parallel and rotatably mounted on the support frame 31. A slider 33 that slides and engages with the support frame 31 is mounted on the first lead screw 32, and the slider 33 is connected to the piston rod of the loading cylinder 34. The second lead screw 35 is located above the first lead screw 32 and has an output platform 5 that slides and engages with the support frame 31. The output platform 5 is used to connect to another loading mechanism or to support a legged robot. That is, in the X-axis loading mechanism 3, the output platform 5 is used to connect to the support frame 31 of the Y-axis loading mechanism 4; in the Y-axis loading mechanism 3, the output platform 5 serves as a pedal for the legged robot's pedaling test. The first lead screw 32 and the second lead screw 35 are connected by a transmission assembly.

[0037] It is important to know that in the pedaling test of the legged robot, the working process of the X-axis loading mechanism 3 and the Y-axis loading mechanism 4 is the same, only the direction of movement is different. For ease of understanding, the following will take the X-axis loading mechanism 3 as an example to describe its specific working process in the pedaling test of the legged robot in detail.

[0038] Specifically, such as Figure 4As shown, with the legged robot's pedaling motion, the output platform 5 of the X-axis loading mechanism 3 moves along the X-axis, thereby driving the second lead screw 35 to rotate. That is, the second lead screw 35 converts the legged robot's pedaling motion into rotational motion. At this time, the rotation of the second lead screw 35 is decelerated by the transmission assembly and transmitted to the first lead screw 32. The first lead screw 32 then extends the piston rod of the loading cylinder 34 via the slider 33. In other words, the first lead screw 32 converts the rotational motion into linear traction motion on the loading cylinder 34. Compared to traditional methods, this application uses a lead screw drive with a reduced stroke, avoiding the need for a thicker cylinder for the long stroke of the loading cylinder 34, which would ultimately lead to a decrease in the back pressure setting value, falling below the proportional overflow setting range, and thus requiring an increase in the minimum pedaling force.

[0039] It is understood that the specific degree to which the reduction component reduces the pedal stroke can be set according to the actual needs of those skilled in the art. For example, it can be reduced to half, one-third, or one-quarter. In this embodiment, it is preferred to reduce the pedal stroke to half; that is, the pedal stroke is L, and the piston rod extension distance of the loading cylinder 34 is L / 2.

[0040] The reduction in pedal stroke by the reduction component can be adjusted through the reduction ratio of the transmission component and / or the lead ratio of the first lead screw 32 and the second lead screw 35. For example, the reduction ratio of the transmission component can be set to 0.5; then, with the same lead of the first lead screw 32 and the second lead screw 35, the second lead screw 35 rotates two revolutions for the first lead screw 32 to rotate one revolution. Alternatively, the lead ratio of the first lead screw 32 and the second lead screw 35 can be set to 0.5; then, with a transmission component speed ratio of 1, the second lead screw 35 drives the output platform 5 to travel a distance of two screw pitches before the first lead screw 32 drives the slider 33 to extend the piston rod of the loading cylinder 34 by one screw pitch. Of course, both the reduction ratio of the transmission component and the lead ratio of the first lead screw 32 and the second lead screw 35 can be set to less than 1.

[0041] In this embodiment, there are various specific structures for the transmission assembly capable of achieving synchronous rotation of the first lead screw 32 and the second lead screw 35. For example, the transmission assembly can adopt a gear transmission structure, a chain transmission structure, or a belt transmission structure, etc. To improve transmission accuracy, a gear transmission structure is preferred in this embodiment. Figure 4 As shown, a first gear 371 is installed at one end of the first lead screw 32, and a second gear 372 is installed at the same end of the second lead screw 372. The first gear 371 and the second gear 372 mesh with each other.

[0042] Those skilled in the art should know that after the legged robot completes its pedaling action, the output platform 5 needs to be reset to its initial position for the next round of pedaling action testing. There are several ways to reset the output platform 5. It can be achieved by using a hydraulic control module to drive the loading cylinder 34, or by driving the first lead screw 32 and the second lead screw 35 to rotate in opposite directions. For ease of understanding, the following detailed explanation will use the example of resetting by rotating the first lead screw 32 and the second lead screw 35 in opposite directions.

[0043] In this embodiment, as Figure 3 and Figure 4 As shown, the stroke reduction assembly also includes a rotating device 36, which is fixedly installed on the support frame 31 and connected to one of the lead screws through the output end. After the legged robot completes the pedaling action, the rotating device 36 can drive the first lead screw 32 to drive the slider 33 to reset, while the second lead screw 35 drives the output platform 5 to reset.

[0044] It is understood that the specific structure and working principle of the rotating device 36 are well known to those skilled in the art, and therefore will not be described in detail here. Common rotating devices 36 include motors, rotary cylinders, and rotary hydraulic cylinders. In this embodiment, a servo motor is preferred. The rotating device 36 can be connected to the first lead screw 32, or it can be connected to the second lead screw 35. Alternatively, two rotating devices 36 can be provided, each connected to one of the two lead screws.

[0045] It is important to note that during the footed robot's pedaling test, the rotation of the first lead screw 32 and the second lead screw 35 is driven by the robot's pedaling force. If the rotating device 36 is in a stopped state, it may interfere with the rotation of the first lead screw 32 and the second lead screw 35. Furthermore, the rotation of the first lead screw 32 and the second lead screw 35 under the pedaling force needs to overcome frictional resistance, which can affect the loading accuracy of the loading cylinder 34. Therefore, in this embodiment, during the footed robot's pedaling test, the rotating device 36 can perform synchronous rotation and continuously output a fixed torque to overcome the frictional force required for the rotation of the first lead screw 32 and the second lead screw 35.

[0046] The fixed torque continuously output by the rotating device 36 can be obtained by calibrating the X-axis loading mechanism 3 and the Y-axis loading mechanism 4 under no-load conditions. That is, with the X-axis loading mechanism 3 and the Y-axis loading mechanism 4 in an unloaded state, the critical value at which the rotating device 36 can just drive the first lead screw 32 and the second lead screw 35 to rotate is taken as the fixed torque continuously output during the pedaling test.

[0047] In this embodiment, as Figure 5As shown, the hydraulic control module includes a replenishment circuit, an overflow valve assembly 308, and a retraction circuit. The first end of the replenishment circuit is connected to the hydraulic pressure source P and the oil tank T, and the second end of the replenishment circuit is connected to the rodless chamber and the rod chamber of the loading cylinder 34. The overflow valve assembly 308 is connected between the rod chamber of the loading cylinder 34 and the oil tank T. One end of the retraction circuit is connected to the rod chamber and the rodless chamber of the loading cylinder 34, and the other end of the retraction circuit is connected to the hydraulic pressure source P and the oil tank T.

[0048] During the pedaling test of the legged robot, the oil replenishment circuit can simultaneously supply oil to both the rod-side and rodless sides of the loading cylinder 34. Simultaneously, the overflow valve assembly 308 connects the rod-side of the loading cylinder 34 to the oil tank T, and can set the overflow pressure to provide back pressure to the rod-side of the loading cylinder 34 to simulate pedaling resistance. At this time, the rod-side of the loading cylinder 34 forms a B-type half-bridge structure through the oil replenishment circuit and the overflow valve assembly 308, effectively improving the stability of the back pressure. After the legged robot completes the pedaling action, the oil replenishment circuit connects both the rod-side and rodless sides of the loading cylinder 34 to the oil tank, ensuring that the loading cylinder 34 is in a floating state with no pressure in either the rod-side or rodless sides. This ensures that the rotating device 36 can smoothly drive the lead screw to reset the piston rod of the loading cylinder 34. The retraction circuit can drive the loading cylinder 34 to reset in case of a malfunction in the rotating device 36.

[0049] In this embodiment, there are various specific structures for the oil replenishment circuit that can achieve the above functions. For ease of understanding, a specific example will be used for detailed explanation below. Figure 5 As shown, the oil replenishment circuit includes a first control valve 303, a second directional valve 307, a first hydraulically controlled check valve 306, a check valve 304, and a second control valve 305. The rodless chamber and rod chamber of the loading cylinder 34 are connected to one side of the first control valve 303 via the first hydraulically controlled check valve 306 and the check valve 304, respectively. The other side of the first control valve 303 is connected to the oil pressure source P to form an oil supply branch. The rod chamber of the loading cylinder 34 is connected to the oil tank T via the second control valve 305 and the relief valve assembly 308 to form a return oil branch. The control end of the first hydraulically controlled check valve 306 is connected to the oil pressure source via the second directional valve 307; the unidirectional conduction direction of the first hydraulically controlled check valve 306 and the check valve 304 faces the loading cylinder 34.

[0050] When the legged robot pedals, the first control valve 303 is turned on to control the oil supply branch to be connected. At this time, the pressure oil from the oil pressure source P flows to the rodless chamber of the loading cylinder 34 through the first hydraulic check valve 306 after passing through the first control valve 303, and flows to the rod chamber of the loading cylinder 34 through the check valve 304. At the same time, the second control valve 305 is turned on to control the return oil branch to be connected. This allows the oil in the rod chamber of the loading cylinder 34 to flow back to the oil tank T through the overflow valve group 308 after passing through the second control valve 305. At this time, the overflow pressure set by the overflow valve group 308 can provide the return oil back pressure to the rod chamber of the loading cylinder 34.

[0051] After the legged robot completes its pedaling motion, the first control valve 303 is shut off, preventing the hydraulic pressure source P from supplying oil. Simultaneously, the second directional valve 307 is opened, which in turn controls the first hydraulic check valve 306 to open, allowing the rodless chamber of the loading cylinder 304 to connect to the oil tank T via the first hydraulic check valve 306. At this time, the second control valve 305 remains open and controls the overflow valve group 308 to adjust the return oil back pressure to zero, which allows the rod chamber of the loading cylinder 304 to be equivalent to being directly connected to the oil tank T.

[0052] It is understood that the specific structures and working principles of the first control valve 303, the second directional valve 307, the first hydraulically controlled check valve 306, the check valve 304, the second control valve 305, and the relief valve assembly 308 are all well-known technologies to those skilled in the art, and therefore will not be described in detail here. For example, the first control valve 303 and the second control valve 305 can be cartridge valves based on solenoid valve pilot control; the second directional valve 307 can be a two-position four-way directional valve, and the check valve 304 can be a hydraulically controlled cartridge valve. The relief valve assembly 308 can be a combination structure of a cartridge valve, a relief valve, and a directional valve. The relief valve can be connected to the control end of the cartridge valve. Based on the relief pressure setting of the relief valve, the pressure at which the cartridge valve opens can be formed, i.e., the return oil back pressure. The directional valve can directly connect the control end of the cartridge valve to the oil tank T to adjust the opening pressure of the cartridge valve to zero, i.e., adjust the return oil back pressure to zero.

[0053] In this embodiment, the hydraulic control module further includes a pressure reducing valve 301 and a first directional valve 302; the hydraulic pressure source P is connected to the input end of the oil supply branch through the pressure reducing valve 301 and the first directional valve 302 connected in sequence. The pressure reducing valve 301 is used to reduce the oil supply pressure of the hydraulic pressure source P to eliminate the frictional resistance generated by the loading cylinder 34 during pedaling; the first directional valve 302 is used to control the working input of the hydraulic pressure source P.

[0054] Understandably, during the extension of the piston rod of the loading cylinder 34, the rodless chamber needs to be replenished with oil in a timely manner to avoid gaps. During the extension, frictional resistance is generated between the piston rod and the cylinder body, which affects the accuracy of the legged robot's pedaling test. Therefore, the oil supply pressure to the rodless chamber of the loading cylinder 34 needs to compensate for the frictional resistance generated by the piston rod's movement. Since the output pressure of the oil pressure source P is generally quite high, it needs to be reduced by the pressure reducing valve 301. The calculation expression for the output pressure P1 of the pressure reducing valve 301 is: F = P1(A1 - A2); where F represents the frictional resistance between the piston rod of the loading cylinder 34 and the cylinder body during extension, and A1 and A2 represent the cross-sectional areas of the rodless and rod-side chambers of the loading cylinder 34, respectively.

[0055] In this embodiment, during the pedaling process of the legged robot, the pedaling motion is not a constant process but a variable-speed motion. This results in the piston rod extension motion of the loading cylinder 34 also being a variable-speed motion. Since the flow rate of the oil replenishment branch is generally constant, when the piston rod motion of the loading cylinder 34 changes abruptly, the flow rate of the oil replenishment branch may not be able to meet the motion requirements of the loading cylinder 34. Therefore... Figure 5 As shown, the hydraulic control module also includes an accumulator 309 connected in parallel to the input end of the oil supply branch. The accumulator 309 can serve as an auxiliary oil source to replenish the oil in time when pedaling too fast.

[0056] In this embodiment, there are various specific structures for the fallback loop that can achieve the above functions. For ease of understanding, a specific example will be used below for detailed explanation. Figure 5 As shown, the retraction circuit includes a third directional valve 310, two second hydraulically controlled check valves 311, and two throttle valves 312. A single second hydraulically controlled check valve 311 is connected to its corresponding throttle valve 312 to form a connecting branch. The rod-side and rodless-side chambers of the loading cylinder 34 are connected to one port of the third directional valve 310 via corresponding connecting branches. The other port of the third directional valve 310 is connected to the hydraulic pressure source P and the oil tank T, respectively. The third directional valve 310 can remain closed when the legged robot is pedaling and the rotating device 36 is working normally. When the legged robot completes pedaling and the rotating device 36 malfunctions, the third directional valve 310 is opened, allowing the hydraulic pressure source P to supply oil to the rod-side chamber of the loading cylinder 34, while the oil in the rodless-side chamber of the loading cylinder 34 flows back to the oil tank T.

[0057] It is understood that the third directional valve 310 is used to control the opening or closing of the retraction circuit, and the throttle valve 312 is used to adjust the retraction speed of the loading cylinder 34. The specific structure and working principle of the third directional valve 310, the second hydraulic check valve 311, and the throttle valve 312 are well known to those skilled in the art, and therefore will not be described in detail here.

[0058] In this embodiment, as Figure 1 and Figure 6 As shown, the tilt simulation mechanism 8 includes four drive cylinders 81 and a control oil circuit. The four drive cylinders 81 are arranged in a 2×2 array, and the control oil circuit is connected to the four drive cylinders 81. The control oil circuit controls the four drive cylinders 81 to perform slightly different extension and retraction movements, so that the overall structure formed by the X-axis loading mechanism 3 and the Y-axis loading mechanism 4 can simulate tilting in different directions and to different degrees. Specifically, when the X-axis loading mechanism 3 is located below the Y-axis loading mechanism 4, the piston rod of the drive cylinder 81 is connected to the support frame 31 of the X-axis loading mechanism 3.

[0059] In this embodiment, as Figure 6 As shown, four control oil circuits are configured in parallel, with each control oil circuit controlling a corresponding drive cylinder 81. The control oil circuits include a third hydraulically controlled check valve 82, a proportional valve 83, and a third directional valve 84. Both the rod-side and rodless-side chambers of the drive cylinder 81 are connected to one port of the proportional valve 83 via the third hydraulically controlled check valve 82. The other port of the proportional valve 83 is connected to both the hydraulic pressure source and the oil tank. One port of the third directional valve 84 is connected to both the hydraulic pressure source and the oil tank, while the other port is connected to two third hydraulically controlled check valves 82. The proportional valve 83 can control the hydraulic pressure source P to supply oil to either the rodless or rod-side chamber of the drive cylinder 81. The third directional valve 84 can control the third hydraulically controlled check valve 82 connected to the non-supply chamber of the drive cylinder 81 to open, allowing the oil in the non-supply chamber to flow back to the oil tank T.

[0060] It is understandable that when simulating tilting of a legged robot in different directions, the third directional valve 84 of part of the control oil circuit can be opened, and the third directional valve 84 of the remaining control oil circuit can be closed, causing part of the drive cylinder 81 to perform upward or downward movements, thereby achieving the tilting of the overall structure formed by the X-axis loading mechanism 3 and the Y-axis loading mechanism 4. Those skilled in the art should know that the Z-axis loading mechanism 1 can be considered as including a single drive cylinder 81 and a corresponding control oil circuit; details can be found above, and therefore will not be repeated here.

[0061] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A test hydraulic system, characterized in that, The system includes a gantry frame and Z-axis, X-axis, and Y-axis loading mechanisms mounted on the gantry frame. The Z-axis loading mechanism is used to mount the legged robot and apply vertical loading. The X-axis and Y-axis loading mechanisms are stacked and used to apply horizontal loading to the legged robot. The loading mechanism that applies loading along the main pedaling direction of the legged robot includes: Support frame; A loading cylinder; the loading cylinder is fixedly installed on the support frame and connected to the hydraulic control module; Hydraulic control module; the hydraulic control module is adapted to provide back pressure when the piston rod of the loading cylinder extends; and A stroke reduction component; the stroke reduction component is installed on the support frame and connected to the piston rod of the loading cylinder through the traction end. The bearing end of the stroke reduction component is used to cooperate with the pedaling motion of the legged robot. The stroke reduction component is adapted to pedal synchronously with the legged robot and to pull the piston rod of the loading cylinder after reducing the stroke of the legged robot according to a set ratio. The range reduction component includes: A first lead screw; the first lead screw is rotatably mounted on the support frame, and a slider that slides on the first lead screw is slidably engaged with the support frame; the slider is connected to the piston rod of the loading cylinder; and The second lead screw is rotatably mounted on the support frame and arranged parallel to the first lead screw. An output platform that slides with the support frame is mounted on the second lead screw. The output platform is used to connect to another loading mechanism or to support a legged robot. The first lead screw and the second lead screw are connected by a transmission assembly. The second lead screw is adapted to convert the pedaling motion of the legged robot into rotational motion, and the first lead screw is adapted to convert the rotational motion into linear traction of the loading cylinder; the extension stroke of the loading cylinder is adjusted by the reduction ratio of the transmission assembly and / or the lead ratio of the first lead screw and the second lead screw.

2. The test hydraulic system as described in claim 1, characterized in that, The stroke reduction assembly also includes a rotating device, which is fixedly installed on the support frame and connected to one of the lead screws through its output end; The rotating device is adapted to continuously output a fixed torque when the legged robot is pedaling to overcome the friction required for the rotation of the first lead screw and the second lead screw; The rotating device is adapted to drive the first lead screw and the second lead screw to reset the output platform and the slider after the legged robot completes the pedaling action.

3. The test hydraulic system as described in claim 1 or 2, characterized in that, The X-axis loading mechanism and the Y-axis loading mechanism have the same structure. The Y-axis loading mechanism is installed above the X-axis loading mechanism and supports the legged robot through the bearing end. The loading direction of the X-axis loading mechanism is along the main pedaling action direction of the legged robot.

4. The test hydraulic system as described in claim 2, characterized in that, The hydraulic control module includes: Oil replenishment circuit; the first end of the oil replenishment circuit is connected to the hydraulic pressure source and the oil tank, and the second end of the oil replenishment circuit is connected to the rodless chamber and the rod chamber of the loading cylinder; Overflow valve assembly; the overflow valve assembly is connected between the rod chamber of the loading cylinder and the oil tank; and A retraction circuit; one end of the retraction circuit is connected to the rod-side chamber and the rodless chamber of the loading cylinder, and the other end of the retraction circuit is connected to the hydraulic power source and the oil tank; The oil replenishment circuit is adapted to simultaneously supply oil to the rod chamber and rodless chamber of the loading cylinder during the pedaling test of the legged robot. At this time, the overflow valve group is adapted to provide back pressure to the rod chamber of the loading cylinder to simulate pedaling resistance. After the legged robot completes the pedaling action, the oil replenishment circuit is adapted to connect both the rod-side chamber and the rodless chamber of the loading cylinder to the oil tank, so that the rotating device drives the lead screw to reset the loading cylinder. The retraction circuit is adapted to drive the loading cylinder to reset when the rotating device malfunctions.

5. The test hydraulic system as described in claim 4, characterized in that, The oil replenishment circuit includes a first control valve, a second reversing valve, a first hydraulically controlled check valve, a check valve, and a second control valve. The rodless chamber and rod chamber of the loading cylinder are respectively connected to one side of the oil port of the first control valve through the first hydraulic check valve and the check valve, and the other side of the oil port of the first control valve is connected to the oil pressure source to form an oil supply branch. The rod chamber of the loading cylinder is connected to the oil tank in sequence through the second control valve and the overflow valve group to form a return oil branch; The control terminal of the first hydraulic check valve is connected to the oil pressure source through the second directional valve; When the legged robot is pedaling, the first control valve controls the oil supply branch to be open, so that the oil pressure source simultaneously supplies oil to the rod chamber and rodless chamber of the loading cylinder. At the same time, the second control valve controls the return oil branch to be open, and provides return oil back pressure to the rod chamber of the loading cylinder through the overflow valve group. After the legged robot completes its pedaling motion, the first control valve is turned off, and the second directional valve is turned on, so that the rodless chamber of the loading cylinder is connected to the oil tank through the first hydraulic check valve. At the same time, the second control valve remains on and controls the overflow valve group to adjust the return oil back pressure to zero.

6. The test hydraulic system as described in claim 4, characterized in that, The retraction circuit includes a third directional valve, two second hydraulically controlled check valves, and two throttle valves; A single second hydraulically controlled check valve is connected to the corresponding throttle valve to form a connection branch; The rod-side chamber and rodless chamber of the loading cylinder are both connected to one side port of the third directional valve through the corresponding connecting branch. The other side port of the third directional valve is connected to the oil pressure source and the oil tank, respectively. The third reversing valve is adapted to remain closed when the legged robot is pedaling and when the rotating device is working normally. When the legged robot completes its pedaling action and the rotating device malfunctions, the third reversing valve is activated, causing the hydraulic pressure source to supply oil to the rod chamber of the loading cylinder, while the oil in the rodless chamber of the loading cylinder flows back to the oil tank.

7. The test hydraulic system as described in claim 5, characterized in that, The hydraulic control module also includes a pressure reducing valve, a first directional valve, and an accumulator; The hydraulic power source is connected to the input end of the oil supply branch through the pressure reducing valve and the first reversing valve connected in sequence. The pressure reducing valve is used to reduce the oil supply pressure of the hydraulic power source to compensate for the friction generated by the loading cylinder during the extension of the piston rod. The first reversing valve is used to control the working cut-in of the hydraulic power source. The accumulator is connected in parallel to the input end of the oil supply branch as an auxiliary oil source.

8. The test hydraulic system as described in claim 1, characterized in that, The test hydraulic system also includes a tilting simulation mechanism, which is located below the X-axis loading mechanism and the Y-axis loading mechanism and connected to the loading mechanism located below the superimposed structure. The tilting simulation mechanism includes four drive cylinders and a control oil circuit; The four drive cylinders are arranged in a 2×2 array, and the control oil circuit is connected to the four drive cylinders; The control oil circuit controls the four drive cylinders to perform slightly different extension and retraction movements, so that the overall structure formed by the X-axis loading mechanism and the Y-axis loading mechanism can simulate tilting in different directions and to different degrees.

9. The test hydraulic system as described in claim 8, characterized in that, The control oil circuit is provided with four circuits, and each control oil circuit controls the corresponding drive cylinder. The control oil circuit includes a third hydraulically controlled check valve, a proportional valve, and a third directional valve; the rod-side and rodless-side chambers of the drive cylinder are both connected to one side of the proportional valve via the third hydraulically controlled check valve, and the other side of the proportional valve is connected to the hydraulic pressure source and the oil tank respectively; one side of the third directional valve is connected to the hydraulic pressure source and the oil tank, and the other side is connected to two of the third hydraulically controlled check valves respectively; The proportional valve is adapted to control the oil pressure source to supply oil to the rodless chamber or rod chamber of the drive cylinder; the third directional valve is adapted to control the third hydraulic control check valve connected to the non-supply chamber of the drive cylinder to open, so that the oil in the non-supply chamber flows back to the oil tank.

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