Low-power reversing valve for a legged robot and its control and feedback regulation method

Abstract

The present invention discloses a low-power reversing valve for a leg-foot robot, as well as its control and feedback regulation method, which relates to the field of reversing valve design. The valve mainly includes: a valve body, a second valve sleeve, a second valve core, a first valve sleeve, a first valve core, a transmission shaft assembly, and a T1 oil port groove group, a P1 oil port groove group, an A oil port groove group, a B oil port groove group, a P2 oil port groove group, and a T2 oil port groove group. The reversing valve realizes the functions of oil circuit connection, cut-off, and commutation by controlling the rotational movement of the valve core relative to the valve body, achieves a large oil flow rate within a small-sized valve body, and requires very small driving torque and power. Only a small motor is needed to complete the flexion and extension of the robot's leg-foot and track the target pressure difference within a certain range in real time. The present invention has excellent characteristics such as small size, light weight, low energy consumption, fast response, large throughput, and small flow resistance, and can replace domestic products of the same type.

Description

Technical Field

[0001] The present invention relates to the field of directional valve design, and particularly to a low-power directional valve for a legged robot and its control and feedback regulation method. Background Art

[0002] Directional valves are widely used in the hydraulic field. They mainly achieve the functions of connecting, cutting off, and reversing oil circuits through the relative movement of the spool within the valve body. Classified by the relative movement mode of the spool and the valve body, there are two types: spool valves and rotary valves.

[0003] Spool valves are the most commonly used directional valves in hydraulic systems. They achieve the reversal of oil circuits by controlling the translational movement of the spool relative to the valve body. Common electromagnetic directional valves and hydraulic directional valves are both spool valves. Spool valves have the advantages of simple structure, convenient control, and mature technology. However, affected by oil pressure, the greater the pressure, the greater the thrust required to control the spool, and the greater the system power consumption. Therefore, they are not suitable for small and low-power hydraulic systems.

[0004] Rotary valves achieve the reversal of oil circuits by controlling the rotational movement of the spool relative to the valve body. A common one is the manual directional valve, which controls the on-off of different oil circuits through the rotation of the handle. Rotary valves have poor sealing performance and unbalanced radial forces, and are generally used in low-pressure and small-flow systems.

[0005] Legged robots need to meet the requirements of being lightweight and convenient. Commonly used directional valves and their hydraulic systems are extremely bulky and require a large battery or fuel for driving. In order to overcome the defects of large power consumption of spool valves and small flow rate of rotary valves, it is necessary to design a directional valve and its control method that are small in size, light in weight, low in energy consumption, fast in response, large in throughput, and small in flow resistance for legged robots. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects in the prior art and provide a low-power directional valve for a legged robot and its control and feedback regulation method, which are small in size, light in weight, low in energy consumption, fast in response, large in throughput, and small in flow resistance. The present invention can effectively realize the functions of the directional valve, achieve a large oil flow rate within a small-sized valve body, and the power for driving the directional valve is only within 10W.

[0007] The specific technical solutions adopted by the present invention are as follows:

[0008] In a first aspect, the present invention provides a low-power directional valve for a legged robot, including a valve body; a second sealing end cover is sealed on the top of the valve body, a first sealing end cover is sealed on the bottom, and an upper valve cavity and a lower valve cavity that are independent of each other are coaxially arranged inside the valve body in the vertical direction. The upper valve cavity and the lower valve cavity are separated by an intermediate plate assembly fixed in the valve body;

[0009] A second valve sleeve and a second valve core which cooperate with each other are arranged in the upper valve cavity. The second valve sleeve is fixed to the inner wall of the valve body, and the second valve core is rotatably connected to the inside of the second valve sleeve. A first valve sleeve and a first valve core which cooperate with each other are arranged in the lower valve cavity. The first valve sleeve is fixed to the inner wall of the valve body, and the first valve core is rotatably connected to the inside of the first valve sleeve. A transmission shaft assembly which penetrates through the second valve core and the first valve core is hermetically arranged at the central axis of the valve body. The second valve core and the first valve core can be driven to rotate synchronously through the transmission shaft assembly.

[0010] Three groups of slots are respectively arranged axially on the second valve sleeve and the second valve core. Each group of slots is arranged circumferentially and are, from top to bottom, a T1 oil port slot group, a P1 oil port slot group, and an A oil port slot group in sequence. Three groups of slots are respectively arranged axially on the first valve sleeve and the first valve core. Each group of slots is arranged circumferentially and are, from top to bottom, a B oil port slot group, a P2 oil port slot group, and a T2 oil port slot group in sequence. The A oil port slot group is always in communication with the oil passage inside the second valve core, and the B oil port slot group is always in communication with the oil passage inside the first valve core. The cooperation relationship of the T1 oil port slot group, the P1 oil port slot group, the P2 oil port slot group, and the T2 oil port slot group can be adjusted by rotation to realize the on-off of different oil port slot groups.

[0011] The A oil port slot group is externally connected to the rod chamber of the hydraulic cylinder of the leg robot through a pipeline, the B oil port slot group is externally connected to the rodless chamber of the hydraulic cylinder of the leg robot through a pipeline, the P1 oil port slot group and the P2 oil port slot group are connected outside the valve body through a pipeline and are connected to the high-pressure oil circuit, and the T1 oil port slot group and the T2 oil port slot group are connected outside the valve body through a pipeline and are connected to the low-pressure oil circuit. Both the high-pressure oil circuit and the low-pressure oil circuit are arranged outside the low-power reversing valve.

[0012] Preferably, the intermediate plate assembly includes a lower intermediate plate and an upper intermediate plate which are arranged in a fitting manner. The lower intermediate plate and the upper intermediate plate are fixedly connected to the inner wall of the valve body to isolate the oil passages inside the first valve core and the second valve core.

[0013] Preferably, both the second sealing end cover and the first sealing end cover are connected to the valve body through threads, and an O-shaped oil seal is arranged at the connection. A dust cover is also arranged on the second sealing end cover.

[0014] Preferably, both the second valve sleeve and the first valve sleeve are fixed to the valve body through positioning pins.

[0015] Preferably, the transmission shaft assembly includes a first coupling cross block, a first transmission shaft, a second transmission shaft, a second coupling cross block, and a pin.

[0016] A first coupling cross block is provided at the bottom of the lower valve cavity, and a second coupling cross block is provided at the top of the upper valve cavity. One end of the first transmission shaft is fixed to the first coupling cross block, and the other end is connected to the bottom of the second coupling cross block through a pin. A second transmission shaft is fixed to the top of the second coupling cross block, and the upper end of the second transmission shaft extends out of the valve body. The first transmission shaft and the second transmission shaft are arranged coaxially and vertically.

[0017] Further, the connection between the second transmission shaft and the valve body is sealed by a hole shaft oil seal and an output shaft sealing support ring.

[0018] Preferably, a motor is also installed on the valve body through a motor mounting seat. Transmission wheels are fixed on both the output shaft of the motor and the transmission shaft assembly, and a transmission belt is connected between the two transmission wheels. The output shaft of the motor can drive the transmission shaft assembly to rotate through the transmission wheels and the transmission belt.

[0019] Preferably, an encoder for measuring rotational displacement is also coaxially fixed at the top of the transmission shaft assembly, and the encoder is installed on the valve body through an encoder mounting seat.

[0020] In a second aspect, the present invention provides a control method for a low-power reversing valve for a leg-foot robot according to any one of the first aspects, specifically as follows:

[0021] By adjusting the opening positions of the T1 oil port groove group, P1 oil port groove group, A oil port groove group, B oil port groove group, P2 oil port groove group, and T2 oil port groove group, the low-power reversing valve can achieve the following three oil circuit connection states:

[0022] In the first state, the rotation angle of the transmission shaft assembly is 0°. At this time, the T1 oil port groove group and the P2 oil port groove group are in a disconnected state, and the P1 oil port groove group and the T2 oil port groove group are in a connected state. The rod chamber of the hydraulic cylinder of the leg-foot robot is filled with high-pressure oil through the connection of the P1 oil port groove group and the A oil port groove group, and the rodless chamber of the hydraulic cylinder of the leg-foot robot is filled with low-pressure oil through the connection of the T2 oil port groove group and the B oil port groove group. Under the action of the pressure difference, the piston rod in the hydraulic cylinder exerts a thrust on the leg-foot, controlling the leg-foot of the robot to be in a flexed state.

[0023] In the second state, the rotation angle of the transmission shaft assembly is 40°. The T1 oil port groove group and the T2 oil port groove group are in a connected state, and the P1 oil port groove group and the P2 oil port groove group are in a disconnected state. At this time, the T1 oil port groove group is connected to the A oil port groove group, and the T2 oil port groove group is connected to the B oil port groove group, so that the rodless chamber and the rod chamber of the hydraulic cylinder of the leg-foot robot are both filled with low-pressure oil with the same pressure, and the hydraulic cylinder does not exert force on the leg-foot, controlling the leg-foot robot to be in a static state.

[0024] In the third state, the rotation angle of the transmission shaft assembly is 80°. At this time, the T1 oil port groove group and the P2 oil port groove group are in a connected state, and the P1 oil port groove group and the T2 oil port groove group are in a disconnected state. The B oil port groove group is connected through the P2 oil port groove group to fill the rodless cavity of the leg-foot robot hydraulic cylinder with low-pressure oil, and the A oil port groove group is connected through the T1 oil port groove group to fill the rodless and rod cavities of the leg-foot robot hydraulic cylinder with high-pressure oil. Under the action of the pressure difference, the piston rod in the hydraulic cylinder exerts a pulling force on the leg-foot to control the robot's leg-foot to be in an extended state.

[0025] When controlling the leg-foot to flex, the transmission shaft assembly is rotated to 0° by the motor drive, so that the piston rod in the hydraulic cylinder returns. The rodless cavity of the hydraulic cylinder is filled with low-pressure oil, and the rod cavity is filled with high-pressure oil, realizing that the hydraulic cylinder provides a pulling force for the leg-foot.

[0026] When controlling the leg-foot to extend, the transmission shaft assembly is rotated from 0° to 80° through 40° by the motor drive, so that the piston rod in the hydraulic cylinder is pushed out. The rodless cavity of the hydraulic cylinder is filled with high-pressure oil, and the rod cavity is filled with low-pressure oil, realizing that the hydraulic cylinder provides a pushing force for the leg-foot.

[0027] In a third aspect, the present invention provides a feedback adjustment method using any one of the low-power reversing valves for leg-foot robots in the first aspect, specifically as follows:

[0028] The transmission shaft assembly is connected to a motor provided with a controller, and the controller is used to control the rotation angle of the transmission shaft assembly through the motor.

[0029] Input the difference e between the ideal pressure difference ΔP between the two chambers of the hydraulic cylinder and the actual pressure difference ΔP between the two chambers of the hydraulic cylinder into the controller, and obtain the flow rate Q(t) through the following formula: d Among them, K is the feedback coefficient, ρ is the density of high-pressure oil and low-pressure oil; P

[0030]

[0031] is the pressure difference coefficient, B is the pressure difference coefficient, P h is the high-pressure oil pressure, P l is the low-pressure oil pressure, v is the piston movement speed of the hydraulic cylinder, v < 0 means the leg-foot flexes, v > 0 means the leg-foot extends; n is an auxiliary parameter;

[0032] Substitute the obtained flow rate Q(t) into the pressure-flow model of the reversing valve, as shown in the following formula, to obtain the actual valve port flow area A of the reversing valve;

[0033]

[0034] Among them, ΔP v is the oil pressure difference before and after passing through the reversing valve, which is calculated by the above formula; Cd is the pressure - flow coefficient of the flow port of the directional valve;

[0035] Subsequently, the actual flow - through area A of the valve port of the obtained directional valve is compared with the maximum flow - through area A when the valve sleeve and the valve core cooperate with each other: If A < A max , then the controller controls the drive shaft assembly to rotate to the angle where A max is located through the motor; otherwise, it indicates that the drive shaft assembly has rotated to the angle where A max is located. max

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] In the present invention, the valve core is axially inserted into the valve sleeve, and the circumferential position of the valve core is adjusted by rotation to achieve the mutual cooperation of the circular grooves on the valve core and the circular grooves on the valve sleeve, so as to realize the on - off and commutation of the oil circuit. Among them, on the same axial section, there are three or six circumferentially evenly distributed circular grooves on both the valve core and the valve sleeve, so as to have a large oil flow rate per unit time. Since the valve core is adjusted for commutation by rotation, the commutation driving force of the device of the present invention is not affected by the oil pressure, but only affected by the resistance generated by friction between the valve core and the valve sleeve and between the drive shaft and the O - type oil seal. Therefore, the commutation driving torque required for this device is very small. When the directional valve remains in a certain state without commutation, the device does not require additional energy consumption to maintain this state. Therefore, the power consumption required for this device is extremely low. The directional valve can track the target pressure difference within a certain range in real - time under the valve core control system. The overall volume of this device is very small and can be placed in a cuboid with a length of 50 mm, a width of 50 mm, and a height of 100 mm, which meets the requirements of light weight, small size, and low power consumption for leg - foot robots. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic structural diagram of a low - power - consumption directional valve;

[0039] Figure 2 is an assembly sectional view of a low - power - consumption directional valve;

[0040] Figure 3 is an axial view of the T1 oil - port groove group, P1 oil - port groove group, P2 oil - port groove group, and T2 oil - port groove group;

[0041] Figure 4 is a three - dimensional structural diagram of the first valve - sleeve device of the low - power - consumption directional valve;

[0042] Figure 5 is a three - dimensional structural diagram of the first valve - core device of the low - power - consumption directional valve;

[0043] Figure 6 is a schematic diagram of the principle of a leg - foot hydraulic system;

[0044] ​Figure 7 It is the oil circuit diagram of the leg and foot in the flexed and extended states;

[0045] Figure 8 It is the schematic diagram of the feedback control of the low-power reversing valve;

[0046] Figure 9 It is the axial view of the oil outlet when the valve core and valve sleeve are not fully mated;

[0047] The reference numerals in the figure are: the first sealing end cover 1, the first valve sleeve 2, the first valve core 3, the valve body 4, the transmission shaft assembly 5, the first coupling cross block 501, the first transmission shaft 502, the second transmission shaft 503, the second coupling cross block 504, the pin 505, the intermediate plate assembly 6, the lower intermediate plate 601, the upper intermediate plate 602, the second valve sleeve 7, the second valve core 8, the second sealing end cover 901, the hole shaft oil seal 902, the shaft outlet sealing support ring 903, the dust cover 904, the motor 10, the transmission wheel 11, the transmission belt 12, the encoder 13, the encoder mounting seat 14, the motor mounting seat 15, the O-ring oil seal 16, the positioning pin 17. Specific embodiments

[0048] The present invention will be further described and explained below in conjunction with the accompanying drawings and specific embodiments. The technical features of each embodiment in the present invention can be combined correspondingly without conflict.

[0049] As Figure 1 and 2 shown, a low-power reversing valve for a leg and foot robot provided by the present invention mainly includes a valve body 4. The top of the valve body 4 is sealed with a second sealing end cover 901, the bottom is sealed with a first sealing end cover 1, and an upper valve cavity and a lower valve cavity are provided inside. The upper valve cavity and the lower valve cavity are coaxially arranged in the vertical direction, and the two valve cavities are independent of each other, separated by an intermediate plate assembly 6 and the two cavities are not communicated with each other. The intermediate plate assembly 6 is hermetically fixed to the inner side wall of the valve body 4 and can completely cover the cross section of the valve body 4 where it is located.

[0050] In this embodiment, the intermediate plate assembly 6 includes a lower intermediate plate 601 and an upper intermediate plate 602. The lower intermediate plate 601 and the upper intermediate plate 602 are arranged in a fitting manner, and both are fixedly connected to the inner wall of the valve body 4 through O-ring seals. Among them, the sealed area surrounded by the second sealing end cover 901, the inner wall of the valve body 4 and the upper intermediate plate 602 is the upper valve cavity, and the sealed area surrounded by the first sealing end cover 1, the inner wall of the valve body 4 and the lower intermediate plate 601 is the lower valve cavity. The second sealing end cover 901 and the first sealing end cover 1 can be threadedly connected to the valve body 4, and an O-ring oil seal 16 is provided at the connection. A dust cover 904 can also be provided on the second sealing end cover 901.

[0051] In the low-power reversing valve of the present invention, a second valve sleeve 7 and a second valve core 8 which cooperate with each other are arranged in the upper valve cavity. The second valve sleeve 7 is fixed to the inner wall of the valve body 4, and the second valve core 8 is rotatably connected to the inside of the second valve sleeve 7. A first valve sleeve 2 and a first valve core 3 which cooperate with each other are arranged in the lower valve cavity. The first valve sleeve 2 is fixed to the inner wall of the valve body 4, and the first valve core 3 is rotatably connected to the inside of the first valve sleeve 2. A transmission shaft assembly 5 which penetrates through the second valve core 8 and the first valve core 3 is hermetically arranged at the central axis of the valve body 4. The second valve core 8 and the first valve core 3 can be driven to rotate synchronously through the transmission shaft assembly 5.

[0052] In the low-power reversing valve of the present invention, the second valve sleeve 7 and the second valve core 8 are respectively provided with three groups of slots along the axial direction. Each group of slots is arranged circumferentially, and are successively the T1 oil port slot group, the P1 oil port slot group, and the A oil port slot group from top to bottom. The first valve sleeve 2 and the first valve core 3 are respectively provided with three groups of slots along the axial direction. Each group of slots is arranged circumferentially, and are successively the B oil port slot group, the P2 oil port slot group, and the T2 oil port slot group from top to bottom. Among them, the A oil port slot group is always in communication with the oil passage inside the second valve core 8, and the B oil port slot group is always in communication with the oil passage inside the first valve core 3. The cooperation relationship of the T1 oil port slot group, the P1 oil port slot group, the P2 oil port slot group, and the T2 oil port slot group can be adjusted by rotation to realize the on-off of different oil port slot groups.

[0053] As Figure 3 shown, the present invention provides a cross-sectional view of the cooperation relationship of the T1 oil port slot group, the P1 oil port slot group, the P2 oil port slot group, and the T2 oil port slot group. The inside of this cross-section is the oil inlet, and the outside is the oil outlet. When the slots of the inner-side valve core of this cross-section exactly align with the slots of the outer-side valve body, the passage of the oil inlet and the oil outlet is realized. There are three slots each on the valve core and the valve sleeve of this cross-section as the flow ports, realizing the characteristic of large flow rate, and the symmetrical structure reduces the interference of the radial force. As Figure 4 and 5 shown, a structural schematic diagram of the first valve sleeve and the first valve core is given. That is to say, slot holes are provided on both the first valve sleeve and the first valve core. The slots at the same cross-section on the first valve sleeve and the first valve core are called a group of slots that can cooperate with each other to realize on-off. The opening positions of each group of slots can be adjusted as needed.

[0054] In the low-power reversing valve of the present invention, as Figure 6As shown in the figure, the A oil port groove group is externally connected to the rod chamber of the hydraulic cylinder of the leg robot through a pipeline, the B oil port groove group is externally connected to the rodless chamber of the hydraulic cylinder of the leg robot through a pipeline, the P1 oil port groove group and the P2 oil port groove group are connected outside the valve body 4 through a pipeline and are connected to the high-pressure oil circuit, and the T1 oil port groove group and the T2 oil port groove group are connected outside the valve body 4 through a pipeline and are connected to the low-pressure oil circuit. The rodless chamber and the rod chamber here are the names defined relative to whether there is a hydraulic rod in the hydraulic cylinder. The side with the hydraulic rod is called the rod chamber, and the side without the hydraulic rod is called the rodless chamber.

[0055] In this embodiment, both the second valve sleeve 7 and the first valve sleeve 2 can be fixed to the valve body 4 through the positioning pin 17. The transmission shaft assembly 5 includes a first coupling cross block 501, a first transmission shaft 502, a second transmission shaft 503, a second coupling cross block 504 and a pin 505. Specifically, a first coupling cross block 501 is provided at the bottom of the lower valve cavity, and a second coupling cross block 504 is provided at the top of the upper valve cavity; one end of the first transmission shaft 502 is fixed to the first coupling cross block 501, and the other end is connected to the bottom of the second coupling cross block 504 through the pin 505; a second transmission shaft 503 is fixed to the top of the second coupling cross block 504, and the upper end of the second transmission shaft 503 extends out of the valve body 4; the first transmission shaft 502 and the second transmission shaft 503 are arranged coaxially and vertically; the connection between the second transmission shaft 503 and the valve body 4 is sealed through the hole shaft oil seal 902 and the shaft outlet sealing support ring 903.

[0056] In this embodiment, a motor 10 is also installed on the valve body 4 through the motor mounting seat 15. Transmission wheels 11 are fixed on both the output shaft of the motor 10 and the transmission shaft assembly 5, and a transmission belt 12 is connected between the two transmission wheels 11. When the output shaft of the motor 10 rotates, it can drive the transmission shaft assembly 5 to rotate through the transmission wheels 11 and the transmission belt 12. A encoder 13 for measuring the rotational displacement is coaxially fixed on the top of the transmission shaft assembly 5, and the encoder 13 is installed on the valve body 4 through the encoder mounting seat 14.

[0057] In this embodiment, the transmission shaft can be restricted to rotate only within a fixed angle range by setting a pin. As shown in Table 1, a method of opening each groove group in this embodiment and the corresponding state of the leg robot are given.

[0058] Table 1

[0059]

[0060] According to Table 1 combined with Figure 7 It can be seen that within this angle range, the low-power reversing valve can achieve the following three oil circuit connection states:

[0061] In the first state, the rotation angle of the transmission shaft assembly 5 is 0°. At this time, the T1 oil port groove group and the P2 oil port groove group are in a disconnected state, and the P1 oil port groove group and the T2 oil port groove group are in a connected state. The rodless cavity of the hydraulic cylinder of the leg-foot robot is filled with high-pressure hydraulic oil by connecting the A oil port groove group through the P1 oil port groove group, and the rodless cavity of the hydraulic cylinder of the leg-foot robot is filled with low-pressure hydraulic oil by connecting the B oil port groove group through the T2 oil port groove group. Under the action of the pressure difference, the piston rod in the hydraulic cylinder applies a thrust to the leg-foot, controlling the leg-foot of the robot to be in a flexed state.

[0062] In the second state, the rotation angle of the transmission shaft assembly 5 is 40°. The T1 oil port groove group and the T2 oil port groove group are in a connected state, and the P1 oil port groove group and the P2 oil port groove group are in a disconnected state. At this time, the T1 oil port groove group is connected to the A oil port groove group, and the T2 oil port groove group is connected to the B oil port groove group, so that both the rodless cavity and the rod cavity of the hydraulic cylinder of the leg-foot robot are filled with low-pressure hydraulic oil with the same pressure, and the hydraulic cylinder does not apply force to the leg-foot, controlling the leg-foot robot to be in a static state.

[0063] In the third state, the rotation angle of the transmission shaft assembly 5 is 80°. At this time, the T1 oil port groove group and the P2 oil port groove group are in a connected state, and the P1 oil port groove group and the T2 oil port groove group are in a disconnected state. The rodless cavity of the hydraulic cylinder of the leg-foot robot is filled with low-pressure hydraulic oil by connecting the B oil port groove group through the P2 oil port groove group, and the rod cavity and the rodless cavity of the hydraulic cylinder of the leg-foot robot are filled with high-pressure hydraulic oil by connecting the A oil port groove group through the T1 oil port groove group. Under the action of the pressure difference, the piston rod in the hydraulic cylinder applies a pulling force to the leg-foot, controlling the leg-foot of the robot to be in an extended state.

[0064] Since the oil port P1 and the oil port P2 are connected in the external oil circuit, and the oil port T1 and the oil port T2 are connected in the external oil circuit, the oil circuit under the structure of this embodiment realizes the function of a three-position four-way directional control valve.

[0065] Based on the opening positions of the above-mentioned T1 oil port groove group, P1 oil port groove group, A oil port groove group, B oil port groove group, P2 oil port groove group and T2 oil port groove group, in this embodiment, the high-pressure oil circuit (P h = 15 MPa) is connected to the oil port P, that is, commonly connected to the oil port P1 and the oil port P2 of the directional control valve. The low-pressure oil circuit (P l = 1.5 MPa) is connected to the oil port T, that is, commonly connected to the oil port T1 and the oil port T2 of the directional control valve. When the motor drives the directional control valve to rotate to 0°, 40°, and 80° respectively, the directional control valve can be switched to the three phases of the left position, the middle position, and the right position as shown in Table 1, specifically as follows:

[0066] When controlling the leg-foot to flex, the transmission shaft assembly 5 is driven by the motor 10 to rotate to 0°, so that the piston rod in the hydraulic cylinder returns. The rodless cavity of the hydraulic cylinder is filled with low-pressure hydraulic oil, and the rod cavity is filled with high-pressure hydraulic oil, realizing that the hydraulic cylinder provides a pulling force for the leg-foot.

[0067] When controlling the leg and foot to extend, the drive shaft assembly 5 is driven by the motor 10 to rotate from 0° through 40° to 80°, so that the piston rod in the hydraulic cylinder is pushed out. The rodless cavity of the hydraulic cylinder is filled with high-pressure hydraulic fluid, and the rod cavity is filled with low-pressure hydraulic fluid, so as to realize that the hydraulic cylinder provides thrust for the leg and foot.

[0068] In addition, the present invention also provides a feedback adjustment method using the above-mentioned low-power reversing valve, which is specifically as follows:

[0069] As Figure 9 shown, when the spool and the valve sleeve are not fully matched, a certain pressure drop will occur when the hydraulic oil passes through the reversing valve. Therefore, when the leg and foot move, since the output force of the hydraulic cylinder is affected by the damping of the reversing valve and the flow rate. In order to ensure that the output thrust of the hydraulic cylinder is consistent with the target thrust, a negative feedback control can be designed to adjust the flow area of the reversing valve to achieve tracking of the target output thrust. In this embodiment, the feedback adjustment is realized by setting a controller. Specifically, the controller is connected to the motor 10. According to the flow rate and the pressure difference between the two chambers of the hydraulic cylinder, the flow area of the valve port of the reversing valve can be inversely calculated and then adjusted, as Figure 8 shown.

[0070] First, the difference e between the ideal pressure difference ΔP d between the two chambers of the hydraulic cylinder and the actual pressure difference ΔP between the two chambers of the hydraulic cylinder is input to the controller, and the flow rate Q(t) is obtained through the following formula:

[0071]

[0072] where K is the feedback coefficient, ρ is the density of the high-pressure hydraulic fluid and the low-pressure hydraulic fluid; P B is the pressure difference coefficient, P h is the high-pressure hydraulic pressure, P l is the low-pressure hydraulic pressure, v is the piston movement speed of the hydraulic cylinder, v<0 means the leg and foot are buckled, v>0 means the leg and foot are extended; n is an auxiliary parameter;

[0073] Subsequently, the obtained flow rate Q(t) is brought into the pressure-flow model of the reversing valve, as shown in the following formula, to obtain the actual flow area A of the valve port of the reversing valve;

[0074]

[0075] where ΔP v is the hydraulic pressure difference before and after passing through the reversing valve, which is calculated by the above formula; C d is the pressure-flow coefficient of the flow port of the reversing valve;

[0076] Subsequently, the obtained actual flow area A of the valve port of the reversing valve is compared with the maximum flow area A max when the valve sleeve and the spool are mutually matched: If A < Amax Then, the controller controls the transmission shaft assembly 5 to rotate to angle A through the motor 10 max ; otherwise, it indicates that the transmission shaft assembly 5 has rotated to angle A max where it is located.

[0077] The directional control valve of the present invention realizes the functions of oil circuit connection, disconnection, and commutation by controlling the rotational movement of the valve core relative to the valve body, achieves a large oil flow rate within a small-sized valve body, and requires very small driving torque and power. Only a small motor is needed to complete the flexion and extension of the robot leg and foot, and to track the target pressure difference within a certain range in real time. The present invention has excellent characteristics such as small size, light weight, low energy consumption, fast response, large throughput, and small flow resistance, and can replace domestic products of the same type.

[0078] The embodiments described above are only a preferred solution of the present invention, but they are not intended to limit the present invention. Various changes and modifications can be made to the various technical features described in the above specific implementation without departing from the spirit and scope of the present invention. For example, increasing or decreasing the number of similar Figure 3 cross-sections on the valve core and the valve sleeve to realize a two-way three-way directional control valve or a three-way six-way directional control valve, etc. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods. Therefore, all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A low-power reversing valve for a legged robot, characterized in that, it includes a valve body (4); a second sealing end cover (901) is sealed at the top of the valve body (4), a first sealing end cover (1) is sealed at the bottom, and an upper valve cavity and a lower valve cavity that are independent of each other are coaxially arranged inside along the vertical direction. The upper valve cavity and the lower valve cavity are separated by an intermediate plate assembly (6) fixed inside the valve body (4); a second valve sleeve (7) and a second valve core (8) that cooperate with each other are arranged in the upper valve cavity. The second valve sleeve (7) is fixed to the inner wall of the valve body (4), and the second valve core (8) is rotatably connected to the inside of the second valve sleeve (7); a first valve sleeve (2) and a first valve core (3) that cooperate with each other are arranged in the lower valve cavity. The first valve sleeve (2) is fixed to the inner wall of the valve body (4), and the first valve core (3) is rotatably connected to the inside of the first valve sleeve (2); a drive shaft assembly (5) that penetrates through the second valve core (8) and the first valve core (3) is hermetically arranged at the central axis of the valve body (4), and the second valve core (8) and the first valve core (3) can be driven to rotate synchronously through the drive shaft assembly (5); the second valve sleeve (7) and the second valve core (8) are respectively provided with three groups of slots along the axial direction, and each group of slots is arranged circumferentially. From top to bottom, they are the T1 oil port slot group, the P1 oil port slot group, and the A oil port slot group; the first valve sleeve (2) and the first valve core (3) are respectively provided with three groups of slots along the axial direction, and each group of slots is arranged circumferentially. From top to bottom, they are the B oil port slot group, the P2 oil port slot group, and the T2 oil port slot group; the A oil port slot group is always in communication with the oil passage inside the second valve core (8), and the B oil port slot group is always in communication with the oil passage inside the first valve core (3); the cooperation relationship of the T1 oil port slot group, the P1 oil port slot group, the P2 oil port slot group, and the T2 oil port slot group can be adjusted by rotation to realize the on-off of different oil port slot groups; the A oil port slot group is externally connected to the rod chamber of the hydraulic cylinder of the legged robot through a pipeline, the B oil port slot group is externally connected to the rodless chamber of the hydraulic cylinder of the legged robot through a pipeline, the P1 oil port slot group and the P2 oil port slot group are connected outside the valve body (4) through a pipeline and are connected to the high-pressure oil circuit, and the T1 oil port slot group and the T2 oil port slot group are connected outside the valve body (4) through a pipeline and are connected to the low-pressure oil circuit.

2. The low-power reversing valve for a legged robot according to claim 1, characterized in that, the intermediate plate assembly (6) includes a lower intermediate plate (601) and an upper intermediate plate (602) that are attached; the lower intermediate plate (601) and the upper intermediate plate (602) are fixedly connected to the inner wall of the valve body (4) to isolate the oil passages inside the first valve core (3) and the second valve core (8).

3. The low-power reversing valve for a legged robot according to claim 1, characterized in that, the second sealing end cover (901) and the first sealing end cover (1) are both connected to the valve body (4) by threads, and an O-ring oil seal (16) is provided at the connection; a dust cover (904) is also provided on the second sealing end cover (901).

4. The low-power reversing valve for a legged robot according to claim 1, characterized in that, Both the second valve sleeve (7) and the first valve sleeve (2) are fixed to the valve body (4) by positioning pins (17).

5. The low-power reversing valve for a legged robot according to claim 1, characterized in that, the transmission shaft assembly (5) includes a first coupling cross block (501), a first transmission shaft (502), a second transmission shaft (503), a second coupling cross block (504) and a pin (505); a first coupling cross block (501) is provided at the bottom of the lower valve cavity, and a second coupling cross block (504) is provided at the top of the upper valve cavity; one end of the first transmission shaft (502) is fixed to the first coupling cross block (501), and the other end is connected to the bottom of the second coupling cross block (504) through a pin (505); a second transmission shaft (503) is fixed to the top of the second coupling cross block (504), and the upper end of the second transmission shaft (503) extends out of the valve body (4); the first transmission shaft (502) and the second transmission shaft (503) are arranged coaxially and vertically.

6. The low-power reversing valve for a legged robot according to claim 5, characterized in that, the connection between the second transmission shaft (503) and the valve body (4) is sealed by a hole shaft oil seal (902) and an output shaft sealing support ring (903).

7. The low-power reversing valve for a legged robot according to claim 1, characterized in that, a motor (10) is further installed on the valve body (4) through a motor mounting seat (15), drive wheels (11) are fixed on the output shaft of the motor (10) and the transmission shaft assembly (5), and a transmission belt (12) is connected between the two drive wheels (11); the output shaft of the motor (10) can drive the transmission shaft assembly (5) to rotate through the drive wheels (11) and the transmission belt (12).

8. The low-power reversing valve for a legged robot according to claim 1, characterized in that, an encoder (13) for measuring rotational displacement is coaxially fixed on the top of the transmission shaft assembly (5), and the encoder (13) is installed on the valve body (4) through an encoder mounting seat (14).

9. A control method using the low-power reversing valve for a legged robot according to any one of claims 1 to 8, characterized in that, specifically as follows: By adjusting the opening positions of the T1 oil port groove group, P1 oil port groove group, A oil port groove group, B oil port groove group, P2 oil port groove group and T2 oil port groove group, the low-power reversing valve can achieve the following three oil circuit connection states: In the first state, the rotation angle of the transmission shaft assembly (5) is 0°, at this time the T1 oil port groove group and the P2 oil port groove group are in a disconnected state, and the P1 oil port groove group and the T2 oil port groove group are in a connected state; the rod chamber of the hydraulic cylinder of the legged robot is filled with high-pressure oil through the connection of the P1 oil port groove group and the A oil port groove group, and the rodless chamber of the hydraulic cylinder of the legged robot is filled with low-pressure oil through the connection of the T2 oil port groove group and the B oil port groove group; under the action of the pressure difference, the piston rod in the hydraulic cylinder exerts a pulling force on the leg, controlling the leg of the robot to be in a flexed state; In the second state, the rotation angle of the transmission shaft assembly (5) is 40°. The T1 oil port groove group and the T2 oil port groove group are in a connected state, and the P1 oil port groove group and the P2 oil port groove group are in a disconnected state. At this time, the T1 oil port groove group is connected to the A oil port groove group, and the T2 oil port groove group is connected to the B oil port groove group, so that the rodless cavity and the rod cavity of the hydraulic cylinder of the legged robot are filled with low-pressure hydraulic oil with the same pressure, and the hydraulic cylinder does not apply force to the legs, controlling the legged robot to be in a static state; In the third state, the rotation angle of the transmission shaft assembly (5) is 80°. At this time, the T1 oil port groove group and the P2 oil port groove group are in a connected state, and the P1 oil port groove group and the T2 oil port groove group are in a disconnected state; the rodless cavity of the hydraulic cylinder of the legged robot is filled with low-pressure hydraulic oil through the P2 oil port groove group connected to the B oil port groove group, and the rodless cavity and the rod cavity of the hydraulic cylinder of the legged robot are filled with high-pressure hydraulic oil through the T1 oil port groove group connected to the A oil port groove group; under the action of the pressure difference, the piston rod in the hydraulic cylinder applies a thrust to the legs, controlling the legs of the robot to be in an extended state; When controlling the legs to flex, the piston rod in the hydraulic cylinder returns, and the transmission shaft assembly (5) rotates to 0°. The rodless cavity of the hydraulic cylinder is filled with low-pressure hydraulic oil, and the rod cavity is filled with high-pressure hydraulic oil, realizing that the hydraulic cylinder provides a pulling force for the legs; When controlling the legs to extend, the piston rod in the hydraulic cylinder is pushed out, and the transmission shaft assembly (5) rotates from 0° through 40° to 80°, so that the rodless cavity of the hydraulic cylinder is filled with high-pressure hydraulic oil, and the rod cavity is filled with low-pressure hydraulic oil, realizing that the hydraulic cylinder provides a thrust for the legs.

10. A feedback adjustment method for a low-power reversing valve for a legged robot according to any one of claims 1 to 8, characterized in that, specifically as follows: The transmission shaft assembly (5) is connected to a motor (10) provided with a controller, and the controller is used to control the rotation angle of the transmission shaft assembly (5) through the motor (10); Input the ideal pressure difference ΔP between the two chambers of the hydraulic cylinder into the controller d The difference e between the actual pressure difference ΔP between the two chambers of the hydraulic cylinder and the ideal value is used to obtain the flow rate Q(t) through the following formula: where K is the feedback coefficient, ρ is the density of the high-pressure and low-pressure hydraulic fluids; P B is the differential pressure coefficient, P h is the high-pressure hydraulic pressure, P l is the low-pressure hydraulic pressure, v is the movement speed of the hydraulic cylinder piston, v < 0 represents leg-foot buckling, v > 0 represents leg-foot extension; n is an auxiliary parameter; Substitute the obtained flow rate Q(t) into the pressure-flow model of the reversing valve, as shown in the following formula, to obtain the actual valve port flow area A of the reversing valve; Among them, ΔP v is the hydraulic pressure difference before and after the directional control valve and is calculated by the above formula; C d is the pressure-flow coefficient of the flow port of the directional control valve; Subsequently, the actual flow area A of the obtained reversing valve port is compared with the maximum flow area A when the valve sleeve and the valve core are in mutual cooperation: If A < A max , the controller controls the drive shaft assembly (5) to rotate to the angle where A max is located through the motor (10); otherwise, it indicates that the drive shaft assembly (5) has rotated to the angle where A max is located. max ​

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