Hydraulic mechanical leg vibration reduction control method based on rotary magneto-rheological damping knee joint

Abstract

The invention relates to a hydraulic mechanical leg vibration reduction control method based on a rotary magneto-rheological damping knee joint, which comprises the following steps of: inputting an error of a displacement signal of a hydraulic actuator into a hydraulic PID (Proportion Integration Differentiation) controller, and controlling the hydraulic actuator to drive a mechanical leg to act; a mechanical leg dynamic model is established, and the loading force on the hydraulic actuator obtained through conversion of torque and force of the mechanical leg is obtained; establishing a hydraulic actuator driving load balance equation; establishing a system motion state discriminant in a stable state; a driving load balance equation and a system motion state discriminant are combined, and expected output damping torque and damper output force with the ideal targets that the force of the hydraulic actuator is balanced and the system motion error is 0 are obtained; and the expected output damping torque is input into the controller, so that the output damping force acts on the hydraulic actuator, and vibration suppression is achieved. According to the invention, system driving load balance and high-precision motion control are both considered, and accurate and efficient damping of the hydraulic mechanical leg can be realized.

Description

Technical Field

[0001] This invention belongs to the field of vibration reduction and control technology for mechanical legs, and particularly relates to a vibration reduction and control method for hydraulic mechanical legs based on a rotary magnetorheological damping knee joint. Background Technology

[0002] Since the beginning of the 21st century, robots have transformed from industrial applications to fields such as medical services, education, entertainment, and surveying and rescue, becoming an important indicator of a country's scientific research level. Hydraulic legged robots possess higher power density and stronger terrain adaptability, showing potential applications in environmental exploration and military transportation in unstructured terrain. The hydraulic valve-controlled cylinder system, as the power actuator of the legged robot, primarily converts the extension and retraction motion of the piston rod into complex gait of the mechanical leg through a leg linkage mechanism. However, the inherent underdamping characteristics of the hydraulic valve-controlled cylinder system have always been a challenging problem in hydraulic systems. The resulting oscillations lead to low precision and poor controllability of hydraulic equipment, causing large contact collision forces or foot oscillations when the legged robot interacts with the ground or performs complex movements. Therefore, improving the vibration reduction and impact resistance of hydraulic legged robots is of great significance for enhancing their motion stability and extending their lifespan.

[0003] In recent years, magnetorheological fluids have gradually come into view as novel smart materials. Magnetorheological fluids possess unique magnetorheological effects, allowing their apparent viscosity to change with the magnitude of an applied magnetic field, providing a novel approach to vibration control in mechanical systems. Based on this, magnetorheological dampers exhibit relatively simple structures, excellent performance, and safe and reliable operation. Their output can be controlled by adjusting the input current, resulting in low energy consumption, fast response, and real-time continuous adjustment of the output.

[0004] While current vibration suppression and control methods for hydraulic mechanical legs offer some solutions, they still have shortcomings and limitations. Traditional vibration reduction solutions suffer from fixed damping and slow response times. Magnetorheological damper control methods suffer from inaccurate control force and current, leading to poor control performance. These shortcomings are mainly as follows:

[0005] 1. Regarding vibration reduction control schemes for hydraulic mechanical legs, current research directions include: hybrid vibration reduction control using hydraulic and electric drive systems; passive control of hydraulic mechanical legs by generating damping using fixed damping dampers; and improving the dynamic response capability of hydraulic systems by optimizing fluid channels, valve design, and fluid flow paths to enhance vibration reduction. Each of these solutions suffers from drawbacks such as system complexity, non-adjustable damping, and poor control adaptability. For example, the paper "Research on Flexible Joints of Rotary Magnetorheological Robots with Variable Stiffness and Damping" combines the damping characteristics of magnetorheological dampers with the variable stiffness characteristics of springs to design a flexible joint capable of variable stiffness and damping, which has been applied to flexible robots. This device has the advantages of compact structure and low energy consumption. However, this method has shortcomings such as the inability to adjust damping stiffness in real time and the inability to directly and quickly respond to vibrations.

[0006] 2. Regarding control methods for magnetorheological dampers: Current control methods mainly include adaptive control, state-space based control, and optimization algorithm-based control. However, for hydraulic mechanical legs using magnetorheological dampers for vibration reduction, existing methods mostly rely on calculations based on single vibration or impact signals for the core vibration reduction design, such as vibration sensor feedback signals, hydraulic actuator displacement, velocity, and load force. This neglects the overall drive load balance of the hydraulic mechanical leg system and the control accuracy requirements during motion. As a result, while vibration reduction may be effective to some extent, when the mechanical leg simultaneously undertakes complex motion control, precise positioning, and force control, the system may experience problems such as response lag, positioning errors, unstable force control, and inconsistent actions. For example, Chinese patent application number 201710583259.7 uses an accelerometer to detect and generate vibration feedback signals to control the magnetorheological damper and adjust its output force and stiffness. While this control strategy provides some vibration buffering, it lacks comprehensive consideration of system motion control and cannot meet the control accuracy requirements. In the master's thesis "Design of Robot Foot Vibration Isolator Based on Magnetorheological Elastomer," the corresponding vibration and impact signals were first obtained by combining the foot contact force curve with the dynamic model of the magnetorheological elastomer (MRE) vibration isolator. A fuzzy PID controller was used to control the current of the MRE vibration isolator, thereby adjusting the damping force to achieve vibration reduction. However, because the output damping force of the MRE vibration isolator is based only on the robot's foot vibration signal and lacks consideration of the overall motion state, this control method suffers from insufficient accuracy in controlling the overall system motion. Summary of the Invention

[0007] The present invention addresses the problems existing in the prior art. Specifically, the technical problem to be solved by the present invention is to provide a vibration reduction control method for a hydraulic mechanical leg based on a rotary magnetorheological damping knee joint, so as to achieve precise and efficient vibration reduction of the hydraulic mechanical leg.

[0008] To achieve the above objectives, the technical solution adopted by this invention is: a vibration reduction control method for a hydraulic mechanical leg based on a rotary magnetorheological damping knee joint. The mechanical leg includes a thigh structure, a knee joint, and a lower leg structure connected in sequence. The knee joint employs a rotary magnetorheological damper. The lower end of the thigh structure is connected to the rotating shaft of the rotary magnetorheological damper. A hydraulic actuator is provided at the rear end of the thigh structure, and the extension end of the hydraulic actuator is connected to the rotation input end of the rotary magnetorheological damper. The upper end of the lower leg structure is connected to the rotation output end of the rotary magnetorheological damper. The hydraulic actuator is controlled by a hydraulic PID controller, and the rotary magnetorheological damper is controlled by a damper PID controller to output damping force. The vibration reduction control method includes the following steps:

[0009] Step S1: Input the error of the displacement signal of the hydraulic actuator in the mechanical leg to the hydraulic PID controller, and drive the mechanical leg to perform the action by controlling the hydraulic actuator;

[0010] Step S2: Establish a dynamic model of the mechanical leg, obtain the torque generated by the mechanical leg through motion, and calculate the load force F on the hydraulic actuator by converting torque to force. L ;

[0011] Step S3: Establish the load balance equation for the hydraulic actuator drive;

[0012] Step S4: Establish a system motion state discriminant based on the system's steady state;

[0013] Step S5: Combine the hydraulic actuator drive load balance equation established in Step S3 with the system motion state discriminant established in Step S4 to obtain the desired output damping torque M and damper output force F of the rotary magnetorheological damper, with the ideal objective of hydraulic actuator force balance and system motion error of 0. M ;

[0014] Step S6: Input the desired output damping torque M0 of the damper to the damper PID controller, which then outputs a signal to the nonlinear controller. After nonlinear control, the output current signal I0 is sent to the motion state compensator, and finally the control current I is sent to the rotating magnetorheological damper, causing the rotating magnetorheological damper to output a damping force F. M It acts on hydraulic actuators to suppress vibration.

[0015] Furthermore, the expression for the hydraulic actuator drive load balance equation established in step S3 is as follows:

[0016]

[0017] Where A is the working area of ​​the hydraulic actuator piston; p1 and p2 are the pressures in the left and right chambers of the hydraulic actuator, respectively; m is the total mass of the hydraulic actuator piston and the external load referred to the hydraulic actuator piston; B p Where is the viscous damping coefficient; K is the load elastic stiffness. p The piston rod of the hydraulic actuator provides feedback displacement. This represents the external force acting on the piston. This is the force output by the magnetorheological damper.

[0018] Furthermore, in the system motion state discrimination formula established in step S4, to ensure that the system motion error is 0, the piston rod of the hydraulic actuator should satisfy:

[0019]

[0020] Where W is the weight matrix, E is the error matrix. ;

[0021] Where k1 and k2 are both constants and k1>0, k2>0; , , These are the piston rod displacement error, speed error, and acceleration error of the hydraulic actuator, respectively.

[0022] Furthermore, the expressions for the piston rod displacement error, velocity error, and acceleration error of the hydraulic actuator are as follows:

[0023] ;

[0024] ;

[0025] ;

[0026] in, , , These are the desired displacement, velocity, and acceleration of the piston rod of the hydraulic actuator, respectively.

[0027] Furthermore, in step S5, the rotary magnetorheological damper, with the ideal objective of achieving force balance of the hydraulic actuator while ensuring zero system motion error, is expected to output a damping force F. M The expression is:

[0028]

[0029] .

[0030] Furthermore, in step S6, the rule for the motion state compensator is: the piston rod displacement error of the hydraulic actuator... Error of piston rod speed with hydraulic actuator When the same sign is present, meaning the hydraulic mechanical leg is moving away from its equilibrium state, the output current signal I = I0; the piston rod displacement error of the hydraulic actuator... Error of piston rod speed with hydraulic actuator When the signal is different, that is, the hydraulic mechanical leg is approaching a balanced state, the output current signal I=0.

[0031] Compared with the prior art, the present invention has the following advantages: The present invention establishes a load balance equation based on the hydraulic actuator drive and an error equation for the system motion state, and solves the two equations simultaneously with two ideal targets with zero error. The resulting desired damping torque M of the rotary magnetorheological damper ensures that the hydraulic mechanical leg completes the desired working condition action. This control method takes into account both system drive load balance and high-precision motion control, and can achieve precise and efficient vibration reduction of the hydraulic mechanical leg. Attached Figure Description

[0032] Figure 1 This is a three-dimensional structural diagram of the mechanical leg in an embodiment of the present invention;

[0033] Figure 2 This is a three-dimensional structural diagram of the rotary magnetorheological damper in an embodiment of the present invention;

[0034] Figure 3 This is a cross-sectional schematic diagram of the rotary magnetorheological damper in an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the operation of the rotating magnetorheological damper knee joint in an embodiment of the present invention;

[0036] Figure 5 This is a block diagram of the vibration reduction control method according to an embodiment of the present invention.

[0037] In the picture:

[0038] 1-Lower leg structure; 2-Rotary magnetorheological damper; 3-Hydraulic actuator; 4-Thigh structure; 5-Rear mechanical leg fixing frame; 6-Base plate; 7-Front mechanical leg fixing frame; 8-Mechanical leg support frame; 9-Knee joint; 10-Metal leg plate; 21-Hydraulic actuator connecting plate; 22-Outer shell end cover; 23-Bearing end cover; 24-Lower leg connecting plate; 25-Sector rotor; 26-Multi-channel stator. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0040] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0041] like Figures 1-4 As shown, the hydraulic mechanical leg includes a thigh structure 4, a knee joint 9, and a lower leg structure 1 connected in sequence. The knee joint 9 adopts a rotary magnetorheological damper 2, which is used to adjust the damping force of the hydraulic mechanical leg. The lower end of the thigh structure 4 is connected to the rotating shaft of the rotary magnetorheological damper 2. A hydraulic actuator 3 is provided at the rear end of the thigh structure 4. The telescopic end of the hydraulic actuator 3 is connected to the rotary input end of the rotary magnetorheological damper 2. The knee joint works in concert with the rotary magnetorheological damper and the hydraulic actuator to adjust the damping force of the knee joint to reduce vibration. The upper end of the lower leg structure 1 is connected to the rotary output end of the rotary magnetorheological damper 2. The hydraulic actuator 3 is controlled by a hydraulic PID controller to drive the hydraulic mechanical leg. The rotary magnetorheological damper 2 is controlled by a damper PID controller to output damping force. The desired damping force of the rotary magnetorheological damper is obtained through a comprehensive control calculation method, and the output current of the rotary magnetorheological damper is controlled by the damper PID controller, thereby controlling the output damping force of the damper to realize vibration reduction of the hydraulic mechanical leg.

[0042] In this hydraulic mechanical leg, such as Figure 4 As shown, when the hydraulic actuator 3 and the rotary magnetorheological damper 2 work in coordination, the damper is subjected to the vibration force of the hydraulic actuator and the leg structure 1 and converts it into rotational torques F1 and F2, and then into rotational torques M1 and M2. After the damper rotates, the magnetorheological fluid flows through the multi-channel rotor and is subjected to the electromagnetic field to form internal chains, generating a damping force that hinders the movement, thereby suppressing the vibration of the hydraulic mechanical leg.

[0043] In this hydraulic mechanical leg, such as Figure 1As shown, the thigh structure 4 includes a base plate 6, a pair of left and right distributed metal leg plates 10, a front mechanical leg fixing frame 7, a rear mechanical leg fixing frame 5, and a mechanical leg support frame 8. The pair of metal leg plates 10 are located below the base plate 6. The lower ends of the pair of metal leg plates 10 are connected to the left and right ends of the rotating shaft of the rotary magnetorheological damper 2 through square holes and fixed with nuts. The hydraulic actuator 3 is hinged to the rotary magnetorheological damper 2 by bolts, transmitting the linear motion of the hydraulic actuator 3 to the rotary magnetorheological damper to become rotational motion. The front mechanical leg fixing frame 7 and the rear mechanical leg fixing frame 5 are both inverted U-shaped and are fixed to the front and rear ends of the bottom of the base plate 6, respectively. The upper ends of the pair of metal leg plates 10 are hinged to the rear mechanical leg fixing frame 5. The front end of the mechanical leg support frame 8 is hinged to the front mechanical leg fixing frame 7, and the rear end is hinged to the pair of metal leg plates 10. The hydraulic actuator 3 is located between a pair of metal leg plates 10, and the base of the hydraulic actuator 3 is rotatably connected to the connecting shaft between the pair of metal leg plates 10.

[0044] In this hydraulic mechanical leg, the rotary magnetorheological damper switches between different operating modes by adjusting the gap between its internal flow channel and the sector block. When the flow channel gap is large, the damper operates in valve mode; while when the gap is small, the damper operates in squeeze valve mode. This mechanism allows the damping force to be adjusted according to the real-time needs of the hydraulic mechanical leg, effectively enhancing vibration reduction performance.

[0045] In this hydraulic mechanical leg, the linear motion of the hydraulic actuator is converted into the rotational motion of a rotary magnetorheological damper. The internal magnetorheological fluid flows through the damping channel, generating damping force under the influence of a magnetic field. This hydraulic mechanical leg utilizes the adjustable damping characteristics of the magnetorheological damper to achieve rapid action response, high position control accuracy, and adaptively adjustable damping force, enabling coupled vibration reduction control of the mechanical leg.

[0046] like Figure 5 As shown, the present invention discloses a hydraulic mechanical leg vibration reduction control method based on a rotary magnetorheological damping knee joint, the vibration reduction control method comprising the following steps:

[0047] Step S1: Input the error of the displacement signal of the hydraulic actuator in the mechanical leg to the hydraulic PID controller, and control the hydraulic actuator to drive the mechanical leg to perform the action through the four-way slide valve;

[0048] Step S2: Establish a dynamic model of the mechanical leg, obtain the torque generated by the mechanical leg through motion, and calculate the load force F on the hydraulic actuator by converting torque to force. L ;

[0049] Step S3: Establish the load balance equation for the hydraulic actuator drive;

[0050] Step S4: Establish a system motion state discriminant based on the system's steady state;

[0051] Step S5: Combine the hydraulic actuator drive load balance equation established in Step S3 with the system motion state discriminant established in Step S4 to obtain the desired output damping torque M and damper output force F of the rotary magnetorheological damper, with the ideal objective of hydraulic actuator force balance and system motion error of 0. M ;

[0052] Step S6: Input the desired output damping torque M0 of the damper to the damper PID controller, which then outputs a signal to the nonlinear controller. After nonlinear control, the output current signal I0 is sent to the motion state compensator, and finally the control current I is sent to the rotating magnetorheological damper, causing the rotating magnetorheological damper to output a damping force F. M It acts on hydraulic actuators to suppress vibration.

[0053] In this embodiment, the expression for the hydraulic actuator drive load balance equation established in step S3 is as follows:

[0054]

[0055] Where A is the working area of ​​the hydraulic actuator piston; p1 and p2 are the pressures in the left and right chambers of the hydraulic actuator, respectively; m is the total mass of the hydraulic actuator piston and the external load referred to the hydraulic actuator piston; B p Where is the viscous damping coefficient; K is the load elastic stiffness. p The piston rod of the hydraulic actuator provides feedback displacement. This represents the external force acting on the piston. This is the force output by the magnetorheological damper.

[0056] In this embodiment, in the system motion state discrimination formula established in step S4, in order to make the system motion error zero, the piston rod of the hydraulic actuator should satisfy:

[0057]

[0058] Where W is the weight matrix, E is the error matrix. ;

[0059] Where k1 and k2 are both constants and k1>0, k2>0; , , These are the piston rod displacement error, speed error, and acceleration error of the hydraulic actuator, respectively.

[0060] In this embodiment, the expressions for the piston rod displacement error, velocity error, and acceleration error of the hydraulic actuator are as follows:

[0061] ;

[0062] ;

[0063] ;

[0064] in, , , These are the desired displacement, velocity, and acceleration of the piston rod of the hydraulic actuator, respectively.

[0065] In this embodiment, in step S5, the rotary magnetorheological damper aims to output a damping force F with the goal of achieving hydraulic actuator force balance and zero system motion error. M The expression is:

[0066]

[0067] ;

[0068] Where R is the distance from the center of the rotary magnetorheological damper to its connection point with the hydraulic actuator.

[0069] In this embodiment, in step S6, the rule of the motion state compensator is: the piston rod displacement error of the hydraulic actuator Error of piston rod speed with hydraulic actuator When the same sign is present, meaning the hydraulic mechanical leg is moving away from its equilibrium state, the output current signal I = I0; the piston rod displacement error of the hydraulic actuator... Error of piston rod speed with hydraulic actuator When the signal is different, that is, the hydraulic mechanical leg is approaching a balanced state, the output current signal I=0.

[0070] This invention applies a rotary magnetorheological damper as a knee joint in a hydraulic mechanical leg structure. The linear motion of the hydraulic actuator is converted into the rotational motion of the rotary magnetorheological damper, allowing the internal magnetorheological fluid to flow through the damping channel and generate damping force under the influence of a magnetic field. By utilizing the adjustable damping characteristics of the rotary magnetorheological damper, a coupled vibration reduction control system for the mechanical leg is achieved, characterized by rapid action response, high position control accuracy, and adaptively adjustable damping force. Specifically, the coupled vibration reduction control method for the magnetorheological damped knee joint establishes a load balance equation based on the hydraulic actuator drive and an error equation based on the system motion state. These two equations are solved simultaneously with two ideal targets having zero error, yielding the desired damping torque M of the rotary magnetorheological damper. This method ensures that the hydraulic mechanical leg completes the desired operating conditions while balancing the system drive load and achieving high-precision motion control, thus enabling precise and efficient vibration reduction for the hydraulic mechanical leg.

[0071] If this invention discloses or relates to components or structural parts that are fixedly connected to each other, then, unless otherwise stated, a fixed connection can be understood as: a fixed connection that can be detached (e.g., using bolts or screws), or a fixed connection that cannot be detached (e.g., riveting, welding). Of course, a fixed connection can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).

[0072] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0073] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A vibration reduction control method for a hydraulic mechanical leg based on a rotary magnetorheological damping knee joint, the mechanical leg comprising a thigh structure, a knee joint, and a lower leg structure connected in sequence, wherein the knee joint employs a rotary magnetorheological damper, the lower end of the thigh structure is connected to the rotating shaft of the rotary magnetorheological damper, a hydraulic actuator is provided at the rear end of the thigh structure, the extension end of the hydraulic actuator is connected to the rotation input end of the rotary magnetorheological damper; the upper end of the lower leg structure is connected to the rotation output end of the rotary magnetorheological damper, characterized in that: The hydraulic actuator is controlled by a hydraulic PID controller, and the rotary magnetorheological damper is controlled by a damper PID controller to output damping force; the vibration reduction control method includes the following steps: Step S1: Input the error of the displacement signal of the hydraulic actuator in the mechanical leg to the hydraulic PID controller, and drive the mechanical leg to perform the action by controlling the hydraulic actuator; Step S2: Establish a dynamic model of the mechanical leg, obtain the torque generated by the mechanical leg through motion, and calculate the load force F on the hydraulic actuator by converting torque to force. L ; Step S3: Establish the load balance equation for the hydraulic actuator drive; Step S4: Establish a system motion state discriminant based on the system's steady state; Step S5: Combine the hydraulic actuator drive load balance equation established in Step S3 with the system motion state discriminant established in Step S4 to obtain the desired output damping torque M and damper output force F of the rotary magnetorheological damper, with the ideal objective of hydraulic actuator force balance and system motion error of 0. M ; Step S6: Input the desired output damping torque M0 of the damper to the damper PID controller, which then outputs a signal to the nonlinear controller. After nonlinear control, the output current signal I0 is sent to the motion state compensator, and finally the control current I is sent to the rotating magnetorheological damper, causing the rotating magnetorheological damper to output damping force F. M It acts on hydraulic actuators to suppress vibration.

2. The vibration reduction control method for a hydraulic mechanical leg based on a rotary magnetorheological damping knee joint according to claim 1, characterized in that: The expression for the hydraulic actuator drive load balance equation established in step S3 is as follows: Where A is the working area of ​​the hydraulic actuator piston; p1 and p2 are the pressures in the left and right chambers of the hydraulic actuator, respectively; m is the total mass of the hydraulic actuator piston and the external load referred to the hydraulic actuator piston; B p Where is the viscous damping coefficient; K is the load elastic stiffness. p The piston rod of the hydraulic actuator provides feedback displacement. This represents the external force acting on the piston. This is the force output by the magnetorheological damper.

3. The vibration reduction control method for a hydraulic mechanical leg based on a rotary magnetorheological damping knee joint according to claim 1, characterized in that: In the system motion state discrimination formula established in step S4, to ensure that the system motion error is 0, the piston rod of the hydraulic actuator should satisfy the following: Where W is the weight matrix, E is the error matrix. ; Where k1 and k2 are both constants and k1>0, k2>0; , , These are the piston rod displacement error, speed error, and acceleration error of the hydraulic actuator, respectively.

4. The hydraulic mechanical leg vibration reduction control method based on a rotary magnetorheological damping knee joint according to claim 3, characterized in that: The expressions for the piston rod displacement error, velocity error, and acceleration error of the hydraulic actuator are as follows: ； ； ； in, , , These are the desired displacement, velocity, and acceleration of the piston rod of the hydraulic actuator, respectively.

5. The hydraulic mechanical leg vibration reduction control method based on a rotary magnetorheological damping knee joint according to claim 1, characterized in that: In step S5, the rotary magnetorheological damper, with the ideal objective of achieving force balance of the hydraulic actuator and zero system motion error, is expected to output a damping force F. M0 The expression is: 。 6. The vibration reduction control method for a hydraulic mechanical leg based on a rotary magnetorheological damping knee joint according to claim 1, characterized in that: In step S6, the rule for the motion compensator is: the piston rod displacement error of the hydraulic actuator Error of piston rod speed with hydraulic actuator When the same sign is present, meaning the hydraulic mechanical leg is moving away from its equilibrium state, the output current signal I = I0; the piston rod displacement error of the hydraulic actuator... Error of piston rod speed with hydraulic actuator When the signal is different, that is, the hydraulic mechanical leg is approaching a balanced state, the output current signal I=0.

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