CN102440854A - Human-machine coupling overload carrying system device and control method thereof - Google Patents

Abstract

The invention relates to a human-machine coupling overload carrying system device and a control method thereof, which is characterized in that pressure sensors and angle sensors are mounted under the feet of a human body and at the knee joints of rigid limbs of an overload carrying system respectively, so as to perceive movement information and force information of the human body and the rigid limbs of the overload carrying system real-timely, and then real-time and accurate information can be provided for human-machine coupling control; through adoption of a human-machine coupling smart control method, different control algorithms are adopted according to different gaits, position feedback control and force feedback control are performed to an executive device, and the movement information and the force information of the human body, which are perceived by the sensors, are transformed into control parameters through filtering and fusion, so that a control actuator can output a proper force real-timely in a follow-up manner, tracks the human body movement and provides an efficient and proper assisting force for the human body movement real-timely; through adoption of a gas energy storage airtight cavity actuator device, the assisting effect of hydraulic cylinder return movement can be achieved, so that flexibility and comfortableness of human-machine coupling movement are improved.

Description

Man-machine coupling heavy-load carrying system device and control method thereof

Technical Field

The present invention relates to a carrying system device and a control method thereof, and more particularly, to a man-machine coupled heavy-load carrying system device and a control method thereof.

Background

In the long journey, people need to carry more and more equipment and supplies, which affects the travelling speed, the walking distance and the maneuverability of people and often leads to mental fatigue or physical injury. When the traditional robot control technology is adopted to assist the human body carrying load exercise, the carrying assisting system is difficult to meet the real-time performance and accuracy of control under the condition of human body load and the flexibility of man-machine cooperative exercise, and particularly under the heavy load condition, when the human body carries out rapid walking, running, jumping and other strenuous exercises, the traditional devices and the control method thereof can cause certain obstruction to the human body exercise, and the exercise cooperativity is influenced.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a human-machine coupled heavy-load carrying system apparatus and a control method thereof, which can improve the real-time performance and accuracy of sensing control of the heavy-load carrying system and the flexibility of human-machine cooperative motion.

The invention adopts the following technical scheme: a man-machine coupling heavy-load carrying system device comprises a rigid limb correspondingly coupled with a lower limb of a human body, wherein the rigid limb comprises two groups of shank parts and thigh parts, two knee joints and actuators connected between the shank parts and the thigh parts, two sensing boots connected to the bottoms of the shank parts, a back frame arranged at the upper parts of the two thigh parts and positioned at the back of the human body, a control system and a power supply; the method is characterized in that: each actuator comprises a hydraulic cylinder, the hydraulic cylinder is connected to the middle part of the thigh part and is sequentially connected with a servo valve, an electro-hydraulic reversing valve, an oil tank and an oil pump through oil pipes, and the oil tank and the oil pump are arranged on the lower part of the back frame; a piston rod of the hydraulic cylinder is connected with the middle part of the shank part, and the inner end of the piston rod is provided with a circle of flange which divides the hydraulic cylinder into a hydraulic cavity and a gas energy storage cavity; the control system comprises two groups of plantar pressure sensors arranged in the two sensing boots, two knee joint angle sensors arranged at the two knee joints, a gait judging module arranged in a control board card on the back frame, an actuator position calculating module, a controller module, an amplifier module, a hydraulic pressure adjusting module, an actuator equivalent module, a supporting load compensation module and two summers; the gait judging module compares and judges the obtained plantar pressure sensor signal with a preset threshold value in the gait judging module; the actuator position calculation module calculates the position Y of the piston rod according to the knee joint angle change value theta output by the knee joint sensor and a relation between the position Y of the piston rod preset in the knee joint angle change value theta; the controller module is through the preset mathematical model expression G of PID controller therein_PIDConverting the obtained deviation value into a voltage control signal U_ctrlAnd outputs it to the amplifier module; the amplifier module passes through a preset relational expression K in the amplifier module_aWill inputVoltage control signal U of_ctrlConverting the current into a servo current amount I and outputting the servo current amount I to a hydraulic adjusting module; the hydraulic adjusting module passes through a relation G preset in the hydraulic adjusting module_svConverting the input servo current I into the opening x of the servo valve_vAnd outputting the data to an actuator equivalent module, wherein the actuator equivalent module outputs an equivalent mathematical model expression G preset in the actuator equivalent module_eqThe opening degree x of the servo valve_vAnd a supporting load compensation force F fed back by the supporting load compensation module_compConverted into the position Y that the piston rod should output_needThe supporting load compensation module is provided with an equivalent mathematical model G preset in the supporting load compensation module_compPosition Y to be output by the piston rod_needSupporting load compensation force F converted into piston rod output_compAnd feeds it back to the equivalent module of the executive.

The two plantar pressure sensors are respectively arranged at the parts contacted with the front sole and the rear heel of the human body, and the plantar pressure sensors output voltage signals.

A mathematical model expression G of a PID controller preset in the controller module_PIDComprises the following steps:

G_PID＝K_P+T_Ds+T_I/s

in the formula: k_PIs a proportionality coefficient, T_DIs a differential coefficient, T_IIs an integral coefficient.

A mathematical model expression G of a PID controller preset in the controller module_PIDComprises the following steps:

G_PID＝K_P+T_Ds+T_I/s

in the formula: k_PIs a proportionality coefficient, T_DIs a differential coefficient, T_IIs an integral coefficient.

The relation between the position Y of the piston rod preset in the actuator position calculation module and the angle change value theta of the knee joint is as follows:

<math> <mrow> <mi>Y</mi> <mo>=</mo> <msqrt> <msup> <mrow> <mi>Dist</mi> <mn>1</mn> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup> <mrow> <mi>Dist</mi> <mn>2</mn> </mrow> <mn>2</mn> </msup> <mo>-</mo> <mn>2</mn> <mo>&times;</mo> <mi>Dist</mi> <mn>1</mn> <mo>&times;</mo> <mi>Dist</mi> <mn>2</mn> <mo>&times;</mo> <mi>cos</mi> <mrow> <mo>(</mo> <msub> <mi>&theta;</mi> <mi>init</mi> </msub> <mo>-</mo> <mi>&theta;</mi> <mo>)</mo> </mrow> </msqrt> </mrow> </math>

in the formula: theta_initIs the initial angle value of the knee joint when the human body stands still and upright, and Dist1 is the distance between the connecting point of the hydraulic cylinder on the thigh part and the knee joint; dist2 is the distance between the connection point of the hydraulic cylinder on the lower leg part and the knee joint;

preset relation K in amplifier module_aComprises the following steps:

$K_a=\frac{I}{U_{\mathrm{ctrl}}}$

in the formula: k_aIs an amplification gain constant;

relation G preset in hydraulic adjusting module_svComprises the following steps:

<math> <mrow> <msub> <mi>G</mi> <mi>sv</mi> </msub> <mo>=</mo> <mfrac> <msub> <mi>x</mi> <mi>v</mi> </msub> <mi>I</mi> </mfrac> <mo>=</mo> <mfrac> <msub> <mi>K</mi> <mi>sv</mi> </msub> <mrow> <mfrac> <msup> <mi>s</mi> <mn>2</mn> </msup> <msup> <msub> <mi>&omega;</mi> <mi>sv</mi> </msub> <mn>2</mn> </msup> </mfrac> <mo>+</mo> <mfrac> <msub> <mrow> <mn>2</mn> <mi>&xi;</mi> </mrow> <mi>sv</mi> </msub> <msub> <mi>&omega;</mi> <mi>sv</mi> </msub> </mfrac> <mi>s</mi> <mo>+</mo> <mn>1</mn> </mrow> </mfrac> </mrow> </math>

in the formula: omega_svIs the natural frequency, ξ, of the servo valve_svIs the damping ratio of the servo valve, K_svIs the gain constant of the servo valve;

equivalent mathematical model G preset in equivalent module of actuator_eqComprises the following steps:

<math> <mrow> <msub> <mi>G</mi> <mi>eq</mi> </msub> <mo>=</mo> <mfrac> <mfrac> <msub> <mi>K</mi> <mi>q</mi> </msub> <msub> <mi>A</mi> <mi>p</mi> </msub> </mfrac> <mrow> <mfrac> <mrow> <msub> <mi>V</mi> <mi>t</mi> </msub> <msub> <mi>m</mi> <mi>t</mi> </msub> </mrow> <mrow> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mrow> </mfrac> <msup> <mi>s</mi> <mn>3</mn> </msup> <mo>+</mo> <mrow> <mo>(</mo> <mfrac> <mrow> <msub> <mi>m</mi> <mi>t</mi> </msub> <msub> <mi>K</mi> <mi>ce</mi> </msub> </mrow> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>+</mo> <mfrac> <mrow> <msub> <mi>B</mi> <mi>e</mi> </msub> <msub> <mi>V</mi> <mi>t</mi> </msub> </mrow> <mrow> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mrow> </mfrac> <mo>)</mo> </mrow> <msup> <mi>s</mi> <mn>2</mn> </msup> <mo>+</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mfrac> <mrow> <msub> <mi>B</mi> <mi>e</mi> </msub> <msub> <mi>K</mi> <mi>ce</mi> </msub> </mrow> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>+</mo> <mfrac> <msub> <mi>KK</mi> <mi>ce</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>)</mo> </mrow> <mi>s</mi> <mo>+</mo> <mfrac> <msub> <mi>KK</mi> <mi>ce</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> </mrow> </mfrac> </mrow> </math>

in the formula: m is_tIs the mass of the shank part of the rigid limb, B_eIs damping of rigid limbs, beta_eIs the modulus of elasticity, K, of the hydraulic oil in the hydraulic cylinder_ceIs the total flow-pressure coefficient of the servo valve, K is the spring rate of the rigid body, K_qIs the flow gain of the servo valve, A_pIs the effective area, V, of the piston rod_tIs the total volume of the hydraulic cylinder;

equivalent mathematical model G preset in supporting load compensation module_compComprises the following steps:

G_comp＝G_YtoFG_FtoFK

wherein,

<math> <mrow> <msub> <mi>G</mi> <mi>FtoFK</mi> </msub> <mo>=</mo> <mfrac> <mn>1</mn> <mrow> <msub> <mi>K</mi> <mi>q</mi> </msub> <msub> <mi>A</mi> <mi>p</mi> </msub> </mrow> </mfrac> <mrow> <mo>(</mo> <msub> <mi>K</mi> <mi>ce</mi> </msub> <mo>+</mo> <mfrac> <msub> <mi>V</mi> <mi>t</mi> </msub> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> </mfrac> <mi>s</mi> <mo>)</mo> </mrow> </mrow> </math>

$G_{\mathrm{YtoF}}=\frac{F_{\mathrm{comp}}}{Y_{\mathrm{need}}}.$

selecting G in the following range according to the gait obtained by the gait judging module_YtoFThe value of (c):

0≤G_YtoF≤1866

wherein, when the walking swing of one leg is performed, G_YtoF＝0；

The control method of the man-machine coupling heavy-load carrying system comprises the following steps: 1) a hydraulic cylinder is arranged on a thigh part of a rigid limb of the man-machine coupling heavy-load carrying system, a piston rod of the hydraulic cylinder is connected with the thigh part of the rigid limb, and a circle of flange is arranged at the inner end of the piston rod to divide the hydraulic cylinder into a hydraulic cavity and a gas energy storage cavity; meanwhile, a sole pressure sensor and a knee joint angle sensor corresponding to a human body are arranged in a control system of the rigid body, and a gait judging module, an actuator position calculating module, a controller module, an amplifier module, a hydraulic adjusting module, an actuator equivalent module, a supporting load compensation module and two adders are arranged on a control board card; 2) the sole pressure sensor acquires sole pressure information, and the knee joint angle sensor acquires knee joint rotation angle information; 3) the gait judging module compares and judges the obtained plantar pressure sensor signal with a preset threshold value in the gait judging module, and selects one of the following three control instructions to execute according to a judging result:

firstly, when the walking support is in a single-leg walking support state, executing a position closed-loop control instruction and a force closed-loop control instruction, and entering a step 4);

executing a position closed-loop control instruction when the two legs are in static support, and entering the step 5);

thirdly, when the user walks and swings with one leg, executing a gradual change open-loop control instruction, and entering the step 6);

4) the actuator position calculation module obtains the knee joint angle expected change value theta output by the knee joint angle sensor_expAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the expected position Y of the piston rod_expAnd output to the adder; the actuator position calculation module obtains the actual change value theta of the knee joint angle output by the knee joint angle sensor_sensorAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the actual position Y of the piston rod_actAnd output to the adder; the adder obtains the expected position Y of the piston rod_expAnd the actual position Y_actSubtracting, and outputting the calculated deviation value to the controller module; the other adder subtracts the obtained sole pressure sensor signal from a sole expected signal value preset in the control system and outputs the calculated deviation value to the controller module; the controller module obtains the expected position Y of the piston rod according to the obtained expected position_expAnd the actual position Y_actAnd the deviation of the sole pressure sensor signal from the sole expected signal value, and a mathematical model expression G of a PID controller preset in the mathematical model expression G_PIDCalculating the voltage control signal U_ctrlAnd outputs it to the amplifier module, and proceeds to step 7); 5) the piston rod is arranged at a desired position Y_expIs set as the maximum value Y of the output position of the piston rod of the actuator when a person is in a two-leg static supporting state_maxAnd output to the adder; the actuator position calculation module obtains the actual change value theta of the knee joint angle output by the knee joint angle sensor_sensorAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the actual position Y of the piston rod_actAnd output to the adder; the adder will get the activityDesired position Y of the stopper rod_expAnd the actual position Y_actSubtracting, and outputting the calculated deviation value to the controller module; the controller module obtains the expected position Y of the piston rod according to the obtained expected position_expAnd the actual position Y_actAnd a mathematical model expression G of a PID controller preset in the deviation value_PIDCalculating the voltage control signal U_ctrlAnd outputs it to the amplifier module, and proceeds to step 7); 6) the actuator position calculation module obtains the knee joint angle expected change value theta output by the knee joint angle sensor_expAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the expected position Y of the piston rod_expAnd output to the adder; the adder obtains the expected position Y of the piston rod_expDirectly outputting the data to a controller module; the controller module obtains the expected position Y of the piston rod according to the obtained expected position_expAnd a mathematical model expression G of a PID controller preset therein_PIDCalculating the voltage control signal U_ctrlAnd outputs it to the amplifier module; 7) the amplifier module passes through a preset relational expression K in the amplifier module_aThe obtained voltage control signal U_ctrlConverting the current into a servo current amount I and outputting the servo current amount I to a hydraulic adjusting module; 8) the hydraulic adjusting module passes through a relation G preset in the hydraulic adjusting module_svConverting the obtained servo current I into the opening size x of the servo valve_vAnd output it to the equivalent module of the actuator; 9) the equivalent module of the actuator is expressed by an equivalent mathematical model expression G preset in the equivalent module_eqThe obtained opening size x of the servo valve_vAnd a supporting load compensation force F fed back by the supporting load compensation module_compConversion into the position Y to be output by the piston rod_needAnd outputs it to the supporting load compensation module; 10) the supporting load compensation module passes through an equivalent mathematical model G preset in the supporting load compensation module_compPosition Y to be output by the piston rod_needSupporting load compensation force F converted into piston rod output_compAnd feeding back the data to the equivalent module of the actuator, and returning to the step 2) until the control system sends an instruction to finish the circulation.

In the step 4), a sole expected signal preset in the control system and a preassigned sole expected supporting force F_expCorrespondingly, the desired supporting force F of the sole_expIs the sum of the weight of the heavy load and the weight of the heavy load carrying system device after the weight of the human body is deducted.

Due to the adoption of the technical scheme, the invention has the following advantages: 1. according to the invention, the pressure sensor and the angle sensor are respectively arranged on the heavy-load carrying system sensing boot and the knee joint of the rigid body, so that the foot sole pressure information and the knee joint angle information of the rigid body can be sensed in real time, and real-time and accurate information is provided for a man-machine coupling control system. 2. The invention adopts a man-machine coupling intelligent control method, adopts different control algorithms according to different gaits, and carries out position feedback control and force feedback control on the executing device, thereby being capable of tracking human body movement in real time and providing high-efficiency and proper assistance for the human body movement. 3. According to the invention, as the hydraulic cylinder actuator device with the gas energy storage cavity is adopted, the power assisting effect of the quick return stroke of the hydraulic cylinder actuator is realized, so that the flexibility and the comfort of the man-machine coupling motion are improved.

Drawings

FIG. 1 is a schematic view of a heavy-duty carrying system according to the present invention

FIG. 2 is a schematic view of an actuator of the present invention

FIG. 3 is a schematic diagram of the operating principle of the control system of the present invention

FIG. 4 is a schematic diagram of a control scheme of the present invention

FIG. 5 is a schematic view of the sole pressure sensor arrangement of the present invention

FIG. 6 is a schematic view of the angular change obtained by the knee joint sensor of the present invention

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in figure 1, the invention comprises a rigid limb correspondingly coupled with the lower limb of the human body, the rigid limb comprises two groups of shank parts 1 and thigh parts 2, two knee joints 3 and actuators 4 connected between the shank parts 1 and the thigh parts 2, two sensing boots 5 connected to the bottoms of the shank parts 1, a back frame 6 arranged at the upper parts of the two thigh parts 2 and positioned at the back of the human body, a control system 7 and a power supply 8.

As shown in fig. 2, the actuator 4 of the present invention comprises a hydraulic cylinder 41, one end of the hydraulic cylinder 41 is connected to the middle of the thigh part 2, and the end is provided with a nozzle 42, the nozzle 42 is connected with a servo valve 43, an electro-hydraulic directional valve 44, a fuel tank and a fuel pump 45 through oil pipes, and the fuel tank and the fuel pump 45 are arranged at the lower part of the back frame 6. A piston rod 46 is inserted at the other end of the hydraulic cylinder 41, a ring of flange 47 is arranged at the inner end of the piston rod 46 to divide the hydraulic cylinder 41 into a hydraulic cavity 48 and a gas energy storage cavity 49, and the outer end of the piston rod 46 is connected to the middle part of the lower leg part 1.

As shown in fig. 3 and 4, the control system 7 of the present invention includes four plantar pressure sensors 71, two knee joint angle sensors 72, a gait determination module 73, an actuator position calculation module 74, a controller module 75, an amplifier module 76, a hydraulic pressure adjustment module 77, an actuator equivalent module 78, a support load compensation module 79 and two adders, which are disposed in a control board card disposed at the lower portion of the back frame 6.

As shown in fig. 5, the four plantar pressure sensors 71 in the control system 7 are divided into two groups, each group having two plantar pressure sensors 71, and the two plantar pressure sensors 71 are respectively placed in the parts of a sensing shoe 5 that are in contact with the forefoot and the heel of the human body. The four plantar pressure sensors 71 send the measured voltage values to the gait determination module 73, and a given voltage threshold is preset in the gait determination module 73 and can be set according to the sensitivity of the sensors and experimental experience. The gait judging module 73 judges the current gait condition of the human body: when the sum of the output values of each of the two groups of plantar pressure sensors 71 is greater than a given voltage threshold, it indicates that the state of "resting support for both legs" is present; when the sum of the output values of only one group of the pressure sensors is larger than a given voltage threshold value, indicating that the leg is in a single-leg walking support state; while the other leg is in a "single leg walking swing" position (as shown in figure 4).

As shown in fig. 1 and 3, the two knee joint angle sensors 72 of the control system 7 are provided at the two knee joints 3, and the two knee joint sensors 72 output the measured knee joint angle change value θ to the actuator position calculation module 74. A relational expression between the current position Y of the piston rod 46 and the knee joint angle variation value θ is preset in the actuator position calculation module 74, and the relational expression is as follows:

<math> <mrow> <mi>Y</mi> <mo>=</mo> <msqrt> <msup> <mrow> <mi>Dist</mi> <mn>1</mn> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup> <mrow> <mi>Dist</mi> <mn>2</mn> </mrow> <mn>2</mn> </msup> <mo>-</mo> <mn>2</mn> <mo>&times;</mo> <mi>Dist</mi> <mn>1</mn> <mo>&times;</mo> <mi>Dist</mi> <mn>2</mn> <mo>&times;</mo> <mi>cos</mi> <mrow> <mo>(</mo> <msub> <mi>&theta;</mi> <mi>init</mi> </msub> <mo>-</mo> <mi>&theta;</mi> <mo>)</mo> </mrow> </msqrt> </mrow> </math>

in the formula: theta_initIs the initial angle value of the knee joint 3 when the human body is still and upright, Dist1 is the distance between the knee joint 3 and the connecting point of the hydraulic cylinder 21 on the thigh part 2; dist2 is the distance between the connection point of the hydraulic cylinder 21 on the lower leg member 1 and the knee joint 3 (as shown in figure 6). When in useWhen the human body is in an upright state, the knee joint angle sensor 72 outputs an angle change value theta of zero; when the shank part 1 is bent backwards, the angle change value theta is set to be a positive value; the angle change value θ is set to a negative value when the lower leg part 1 extends forward. The actuator position calculating module 74 may calculate the piston rod position Y according to the known knee joint angle variation value θ, or conversely, may calculate the knee joint angle variation value θ according to the known piston rod position Y.

As shown in fig. 3, the mathematical model expression G of the first-order and second-order PID controllers is preset in the controller module 75 of the control system 7_PID：

G_PID＝K_P+T_Ds+T_I/s

The controller module 75 may adjust the scaling factor K in the above equation according to the gait and the system performance requirements (e.g., stability, tracking accuracy, and rapidity)_PDifferential coefficient T_DAnd integral coefficient T_IThe control parameters are chosen to be different values. The function of the controller module 75 is to convert the derived deviation into a voltage control signal U_ctrlAnd output to the amplifier module 76. Other forms of mathematical controller models may also be preset in the controller module 75.

As shown in fig. 3, a voltage control signal U provided by a controller module 75 is preset in an amplifier module 76 of the control system 7_ctrlRelation K with servo current I_a：

$K_a=\frac{I}{U_{\mathrm{ctrl}}}$

K_aIs an amplification gain constant, and the magnitude of the amplification gain constant can be set according to the system requirements. The function of the amplifier module 76 is to control the voltage U given by the controller module 75_ctrlConverts it into the amount of servo current I, and outputs the amount of servo current I to the hydraulic pressure adjusting module 77.

As shown in FIG. 3, a servo current I and an opening x of the valve of the servo valve 43 are preset in the hydraulic pressure regulation module 77 of the control system 7_vRelation G of_sv：

<math> <mrow> <msub> <mi>G</mi> <mi>sv</mi> </msub> <mo>=</mo> <mfrac> <msub> <mi>x</mi> <mi>v</mi> </msub> <mi>I</mi> </mfrac> <mo>=</mo> <mfrac> <msub> <mi>K</mi> <mi>sv</mi> </msub> <mrow> <mfrac> <msup> <mi>s</mi> <mn>2</mn> </msup> <msup> <msub> <mi>&omega;</mi> <mi>sv</mi> </msub> <mn>2</mn> </msup> </mfrac> <mo>+</mo> <mfrac> <msub> <mrow> <mn>2</mn> <mi>&xi;</mi> </mrow> <mi>sv</mi> </msub> <msub> <mi>&omega;</mi> <mi>sv</mi> </msub> </mfrac> <mi>s</mi> <mo>+</mo> <mn>1</mn> </mrow> </mfrac> </mrow> </math>

In the formula: omega_svIs the natural frequency, ξ, of the servo valve 43_svIs the damping ratio, K, of the servo valve 43_svIs the gain constant of the servo valve 43, K_svIs determined by the performance parameters of the servo valve 43. The function of the hydraulic regulation module 77 is to convert the amount of servo current I given by the amplifier module 76 into the size x of the opening of the valve of the servo valve 43_vThereby regulating the flow of hydraulic oil into hydraulic chamber 48.

The piston rod 46 in the actuator 4 of the invention overcomes the weight constraint force to move to the position to be reached under the action of the hydraulic oil entering the hydraulic cavity 48, thereby tracking the human body movement in real time and providing high-efficiency and proper assistance for the human body movement. Referring to technical data about the principle of a position feedback control system in a hydraulic control system, the actuator 4 of the invention is expressed by the following mathematical model formula:

<math> <mrow> <msub> <mi>Y</mi> <mi>need</mi> </msub> <mo>=</mo> <mfrac> <mrow> <mfrac> <msub> <mi>K</mi> <mi>q</mi> </msub> <msub> <mi>A</mi> <mi>p</mi> </msub> </mfrac> <msub> <mi>x</mi> <mi>v</mi> </msub> <mo>-</mo> <mfrac> <mn>1</mn> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mrow> <mo>(</mo> <msub> <mi>K</mi> <mi>ce</mi> </msub> <mo>+</mo> <mfrac> <msub> <mi>V</mi> <mi>t</mi> </msub> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> </mfrac> <mi>s</mi> <mo>)</mo> </mrow> <msub> <mi>F</mi> <mi>comp</mi> </msub> </mrow> <mrow> <mfrac> <mrow> <msub> <mi>V</mi> <mi>t</mi> </msub> <msub> <mi>m</mi> <mi>t</mi> </msub> </mrow> <mrow> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mrow> </mfrac> <msup> <mi>s</mi> <mn>3</mn> </msup> <mo>+</mo> <mrow> <mo>(</mo> <mfrac> <mrow> <msub> <mi>m</mi> <mi>t</mi> </msub> <msub> <mi>K</mi> <mi>ce</mi> </msub> </mrow> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>+</mo> <mfrac> <mrow> <msub> <mi>B</mi> <mi>e</mi> </msub> <msub> <mi>V</mi> <mi>t</mi> </msub> </mrow> <mrow> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mrow> </mfrac> <mo>)</mo> </mrow> <msup> <mi>s</mi> <mn>2</mn> </msup> <mo>+</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mfrac> <mrow> <msub> <mi>B</mi> <mi>e</mi> </msub> <msub> <mi>K</mi> <mi>ce</mi> </msub> </mrow> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>+</mo> <mfrac> <msub> <mi>KK</mi> <mi>ce</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>)</mo> </mrow> <mi>s</mi> <mo>+</mo> <mfrac> <msub> <mi>KK</mi> <mi>ce</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> </mrow> </mfrac> </mrow> </math>

in the formula: f_compIs a supporting load compensating force, Y_needIs the position, m, that the piston rod 46 should output_tIs the mass of the shank part 1 of the rigid limb, B_eIs damping of rigid limbs, beta_eIs the modulus of elasticity, K, of the hydraulic oil in the hydraulic cylinder 41_ceIs the total flow-pressure coefficient of the servo valve 43, K is the spring rate of the rigid body, K_qIs the flow gain of the servo valve 43, A_pIs the effective area, V, of the piston rod 46_tIs the total volume of the hydraulic cylinder 41. The above formula can also be equivalent to:

Y_need＝(x_v-Y_needG_YtoFG_FtoFK)×G_eq

wherein,

<math> <mrow> <msub> <mi>G</mi> <mi>eq</mi> </msub> <mo>=</mo> <mfrac> <mfrac> <msub> <mi>K</mi> <mi>q</mi> </msub> <msub> <mi>A</mi> <mi>p</mi> </msub> </mfrac> <mrow> <mfrac> <mrow> <msub> <mi>V</mi> <mi>t</mi> </msub> <msub> <mi>m</mi> <mi>t</mi> </msub> </mrow> <mrow> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mrow> </mfrac> <msup> <mi>s</mi> <mn>3</mn> </msup> <mo>+</mo> <mrow> <mo>(</mo> <mfrac> <mrow> <msub> <mi>m</mi> <mi>t</mi> </msub> <msub> <mi>K</mi> <mi>ce</mi> </msub> </mrow> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>+</mo> <mfrac> <mrow> <msub> <mi>B</mi> <mi>e</mi> </msub> <msub> <mi>V</mi> <mi>t</mi> </msub> </mrow> <mrow> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mrow> </mfrac> <mo>)</mo> </mrow> <msup> <mi>s</mi> <mn>2</mn> </msup> <mo>+</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mfrac> <mrow> <msub> <mi>B</mi> <mi>e</mi> </msub> <msub> <mi>K</mi> <mi>ce</mi> </msub> </mrow> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>+</mo> <mfrac> <msub> <mi>KK</mi> <mi>ce</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>)</mo> </mrow> <mi>s</mi> <mo>+</mo> <mfrac> <msub> <mi>KK</mi> <mi>ce</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> </mrow> </mfrac> </mrow> </math>

<math> <mrow> <msub> <mi>G</mi> <mi>FtoFK</mi> </msub> <mo>=</mo> <mfrac> <mn>1</mn> <mrow> <msub> <mi>K</mi> <mi>q</mi> </msub> <msub> <mi>A</mi> <mi>p</mi> </msub> </mrow> </mfrac> <mrow> <mo>(</mo> <msub> <mi>K</mi> <mi>ce</mi> </msub> <mo>+</mo> <mfrac> <msub> <mi>V</mi> <mi>t</mi> </msub> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> </mfrac> <mi>s</mi> <mo>)</mo> </mrow> </mrow> </math>

$G_{\mathrm{YtoF}}=\frac{F_{\mathrm{comp}}}{Y_{\mathrm{need}}}$

as shown in fig. 3, the actuator equivalent module 78 of the control system 7 is preset with the equivalent mathematical model G_eq. The function of the equivalent actuator module 78 is to adjust the opening x of the valve of the servo valve 43 given by the hydraulic pressure adjustment module 77_vAnd supporting load compensation force F given by supporting load compensation module 79_compConverted into the position Y of the actuator 4 at which the piston rod 46 should be output_needThereby controlling the piston rod 46 in the actuator 4 to move to the position that should be reached.

As shown in FIG. 3, an equivalent mathematical model G is preset in the supporting load compensation module 79 of the control system 7_comp：

G_comp＝G_YtoFG_FtoFK

In the above formula, according to different gaits, G_YtoFAlso different in value, and G is obtained according to experimental tests_YtoFThe value ranges of (a) are generally:

0≤G_YtoF≤1866

when in single-leg walking swing, G_YtoF＝0。

The function of the supporting load compensation module 79 is to take into account the currently obtained position Y that the piston rod 46 should output_needCalculating the supporting load compensation force F that should be output by the piston rod 46 at present_compAnd outputs feedback to the actuator equivalent module 78.

Open loop transfer function G of the entire control system 7_openNamely:

$G_{\mathrm{open}}=\frac{G_{\mathrm{PID}}{K}_a{G}_{\mathrm{sv}}{G}_{\mathrm{eq}}}{(1+G_{\mathrm{hyd}\_\mathrm{eq}}{G}_{\mathrm{YtoF}}{G}_{\mathrm{FtoFK}})}$

as shown in fig. 4, the power supply 8 of the present invention is disposed at the lower portion of the back frame 6, and the power supply 8 may be a lithium battery device, and the lithium battery supplies power to the electric devices such as the plantar pressure sensor 71, the knee joint angle sensor 72, the control system 7, the servo valve 43, and the oil pump.

As shown in fig. 3, the control system 7 operates as follows:

when the human body moves, the knee joint generates a desired rotation angle theta_expThe angle is measured by the knee angle sensor 72 and transmitted to the actuator position calculation module 74 to calculate the desired position Y of the piston rod 46 in the actuator 4_exp(ii) a Meanwhile, the knee joint angle sensor 72 measures the actual knee joint 3 rotation angle θ_sensorThe actual position Y of the current piston rod 46 is calculated by the actuator position calculation module 74_act(ii) a Desired position Y of piston rod 46_expAnd an actual position Y_actAre all input to the adder, the subtracted deviation value is used as the input signal of the controller block 75, and the controller block 75 outputs the corresponding voltage control signal U_ctrlVoltage control signal U_ctrlThe signal is converted into a servo current signal I by an amplifier module 76, the servo current signal I is input to a hydraulic pressure adjusting module 77, and the opening degree x of the valve of the servo valve 43 is calculated_vThereby regulating the amount of oil flow into hydraulic chamber 48. In addition, the gait determination module 73 determines the current gait according to the voltage value output by the plantar pressure sensor 71. The supporting load compensation module 79 gives the supporting load compensation force F required to be output by the piston rod 46 of the actuator 4 according to the current gait_compSupporting load compensation force F_compAnd the opening size x of the valve of the hydraulic valve_vAre input together into an actuator equivalent module 78, which calculates the position Y that the piston rod 46 should output_need. By the closed-loop feedback control of the position of the piston rod 46, the rotation angle of the shank part 1 relative to the thigh part 2 can be kept consistent with the angle expected to change by the knee joint when a person moves the legs, and the purpose of man-machine coordination movement is achieved. When the human leg is in the state of single leg walking support, the voltage value output by the plantar pressure sensor 71 is input into another adder and is compared with a desired voltage value U preset in the control system 7_expThe difference is also input to the controller block 75 as an input signal for force feedback control. Wherein the desired voltage value U_expIs a predetermined desired supporting force F of the sole_expCorresponding voltage value, desired supporting force F of sole_expCan be set as the sum of the dead weight of the carrying system device with heavy load and the dead weight of the human body after deducting the dead weight of the human body, U_expAnd F_expThe corresponding relationship of (a) is determined by the conversion relationship between the input and output of the plantar pressure sensor 71, and the conversion relationship is different for different plantar pressure sensors. Thus, by the force closed loop feedback control, the piston rod 46 can rapidly exert force in the single-leg walking support stage, and the interference force generated by load is compensated, so that people can feel labor-saving.

The actuator 4 works according to the following principle:

when the control system 7 of the invention sends out a command signal, the electro-hydraulic directional valve 44 of the actuator 4 is switched on in the positive direction, hydraulic oil enters the hydraulic cavity 48 through the nozzle 42, under the action of the hydraulic oil, the piston rod 46 moves to enable the shank part 1 of the rigid body to move, and meanwhile, the air sealed in the gas energy storage cavity 49 is compressed; when the control system 7 sends a signal to enable the electro-hydraulic directional valve 44 to return to the middle position, hydraulic oil cannot enter the hydraulic cavity 48, oil in the hydraulic cavity 48 cannot return to the oil tank, and the actuator 4 becomes a rigid structural part to support load; when the control system 7 sends a signal, the electro-hydraulic directional valve 44 is reversely connected, the hydraulic cavity 48 is connected with the oil tank, the piston rod 46 returns rapidly under the combined action of compressed air in the gas energy storage cavity 49 and the torque of the legs when the human body naturally walks, and oil in the hydraulic cavity 48 is pressed back to the oil tank.

The control method comprises the following steps:

1) the sole pressure sensor acquires sole pressure information, and the knee joint angle sensor acquires knee joint rotation angle information;

2) the gait judging module compares and judges the obtained plantar pressure sensor signal with a preset threshold value in the gait judging module, and selects one of the following three control instructions to execute according to a judging result:

firstly, when the walking support is in a single-leg walking support state, executing a position closed-loop control instruction and a force closed-loop control instruction, and entering a step 3);

secondly, when the two legs are in static support, executing a position closed-loop control instruction, and entering the step 4);

thirdly, when the user walks and swings with one leg, executing a gradual change open-loop control instruction, and entering the step 5);

3) the actuator position calculation module obtains the knee joint angle expected change value theta output by the knee joint angle sensor_expAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the expected position Y of the piston rod_expAnd output to the adder;

the actuator position calculation module obtains the actual change value theta of the knee joint angle output by the knee joint angle sensor_sensorAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the actual position Y of the piston rod_actAnd output to the adder;

the adder obtains the expected position Y of the piston rod_expAnd the actual position Y_actSubtracting, and outputting the calculated deviation value to the controller module;

the other adder subtracts the obtained sole pressure sensor signal from a sole expected signal value preset in the control system and outputs the calculated deviation value to the controller module;

the controller module obtains the expected position Y of the piston rod according to the obtained expected position_expAnd the actual position Y_actAnd the deviation of the sole pressure sensor signal from the sole expected signal value, and a mathematical model expression G of a PID controller preset in the mathematical model expression G_PIDCalculating the voltage control signal U_ctrlAnd outputs it to the amplifier module, and proceeds to step 6);

4) the piston rod is arranged at a desired position Y_expIs set as the maximum value Y of the output position of the piston rod of the actuator when a person is in a two-leg static supporting state_maxAnd output to the adder;

the actuator position calculation module obtains the actual change value theta of the knee joint angle output by the knee joint angle sensor_sensorAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the actual position Y of the piston rod_actAnd output to the adder;

the adder obtains the expected position Y of the piston rod_expAnd the actual position Y_actSubtracting, and outputting the calculated deviation value to the controller module;

the controller module obtains the expected position Y of the piston rod according to the obtained expected position_expAnd the actual position Y_actAnd a mathematical model expression G of a PID controller preset in the deviation value_PIDCalculating the voltage control signal U_ctrlAnd outputs it to the amplifier module, and proceeds to step 6);

5) the actuator position calculation module obtains the knee joint angle expected change value theta output by the knee joint angle sensor_expAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the expected position Y of the piston rod_expAnd output to the adder;

the adder obtains the expected position Y of the piston rod_expDirectly outputting the data to a controller module;

the controller module is based on the obtainedDesired position Y of the piston rod_expAnd a mathematical model expression G of a PID controller preset therein_PIDCalculating the voltage control signal U_ctrlAnd outputs it to the amplifier module;

6) the amplifier module passes through a preset relational expression K in the amplifier module_aThe obtained voltage control signal U_ctrlConverting the current into a servo current amount I and outputting the servo current amount I to a hydraulic adjusting module;

7) the hydraulic adjusting module passes through a relation G preset in the hydraulic adjusting module_svConverting the obtained servo current I into the opening size x of the servo valve_vAnd output it to the equivalent module of the actuator;

8) the equivalent module of the actuator is expressed by an equivalent mathematical model expression G preset in the equivalent module_eqThe obtained opening size x of the servo valve_vAnd a supporting load compensation force F fed back by the supporting load compensation module_compConversion into the position Y to be output by the piston rod_needAnd outputs it to the supporting load compensation module;

9) the supporting load compensation module passes through an equivalent mathematical model G preset in the supporting load compensation module_compPosition Y to be output by the piston rod_needSupporting load compensation force F converted into piston rod output_compAnd feeding back the data to the equivalent module of the actuator, and returning to the step 1) until the control system sends an instruction to finish the circulation.

In the above embodiment, the knee joint angle sensor may adopt a rotary incremental encoder.

In the above embodiment, when more accurate position servo tracking control is required, the actuator may further adopt motor power drive instead of hydraulic pump power drive, and the embodiment is similar to the hydraulic pump power drive, except that: the rotating motion of the permanent magnet brushless motor is converted into the reciprocating linear motion of the knee joint hydraulic cylinder actuator through the conversion device, and the controller can realize accurate servo tracking control of different expected positions only by controlling the rotating speed of the motor in different motion states, so that the coordination control of certain special actions such as going upstairs and downstairs, kicking legs, squatting and the like can be realized.

The above embodiments are only used for illustrating the present invention, and the structure, connection mode and the like of each component can be changed, and all equivalent changes and modifications based on the technical scheme of the present invention should not be excluded from the protection scope of the present invention.

Claims (8)

1. A device of a man-machine coupling heavy-load carrying system comprises a rigid limb correspondingly coupled with a lower limb of a human body, wherein the rigid limb comprises two groups of shank parts and thigh parts, two knee joints and actuators connected between the shank parts and the thigh parts, two sensing shoes connected to the bottoms of the shank parts, a back frame arranged at the upper parts of the two thigh parts and positioned at the back of the human body, a control system and a power supply; the method is characterized in that:

each actuator comprises a hydraulic cylinder, the hydraulic cylinder is connected to the middle part of the thigh part and is sequentially connected with a servo valve, an electro-hydraulic reversing valve, an oil tank and an oil pump through oil pipes, and the oil tank and the oil pump are arranged on the lower part of the back frame; a piston rod of the hydraulic cylinder is connected with the middle part of the shank part, and a circle of flange which divides the hydraulic cylinder into a hydraulic cavity and a gas energy storage cavity is arranged at the inner end of the piston rod;

the control system comprises two groups of plantar pressure sensors arranged in the two sensing boots, two knee joint angle sensors arranged at the two knee joints, a gait judging module, an actuator position calculating module, a controller module, an amplifier module, a hydraulic adjusting module, an actuator equivalent module, a supporting load compensation module and two summers, wherein the gait judging module, the actuator position calculating module, the controller module, the amplifier module, the hydraulic adjusting module, the actuator equivalent module, the supporting load compensation module and the two summers are arranged in a control board card on the back frame;

the gait judging module compares and judges the obtained plantar pressure sensor signal with a preset threshold value in the gait judging module; the actuator position calculating module calculates the position Y of the piston rod according to the knee joint angle change value theta output by the obtained knee joint sensor and a relational expression between the position Y of the piston rod preset in the knee joint angle change value theta; the controller module is used for controlling the PID controller through a preset mathematical model expression G_PIDConverting the obtained deviation value into a voltage control signal U_ctrlAnd outputs it to the amplifier module; the amplifier module passes through a preset relational expression K in the amplifier module_aThe input voltage control signal U_ctrlConverting the current into a servo current amount I and outputting the servo current amount I to the hydraulic adjusting module; the hydraulic adjusting module passes through a relation G preset in the hydraulic adjusting module_svConverting the input servo current I into the opening x of the servo valve_vAnd outputting the equivalent data to the equivalent module of the actuator, wherein the equivalent module of the actuator outputs the equivalent data to the equivalent module of the actuator through an equivalent mathematical model expression G preset in the equivalent module of the actuator_eqThe opening degree x of the servo valve_vAnd a supporting load compensation force F fed back by the supporting load compensation module_compConverted into the position Y that the piston rod should output_needThe supporting load compensation module is provided with an equivalent mathematical model G preset in the supporting load compensation module_compThe piston rodPosition Y to be output_needA supporting load compensation force F converted into the force which the piston rod should output_compAnd feeds back the equivalent module of the actuator.

2. The apparatus of claim 1, wherein the portable system further comprises: the two plantar pressure sensors are respectively arranged at the parts contacted with the front sole and the rear heel of the human body, and the plantar pressure sensors output voltage signals.

3. The apparatus of claim 1, wherein the portable system further comprises: a mathematical model expression G of a PID controller preset in the controller module_PIDComprises the following steps:

G_PID＝K_P+T_Ds+T_I/s

in the formula: k_PIs a proportionality coefficient, T_DIs a differential coefficient, T_IIs an integral coefficient.

4. The apparatus of claim 2, wherein the portable device comprises: a mathematical model expression G of a PID controller preset in the controller module_PIDComprises the following steps:

G_PID＝K_P+T_Ds+T_I/s

in the formula: k_PIs a proportionality coefficient, T_DIs a differential coefficient, T_IIs an integral coefficient.

5. The apparatus of claim 1, 2, 3 or 4, wherein the heavy-duty portable system further comprises: the relation between the position Y of the piston rod preset in the actuator position calculation module and the angle change value theta of the knee joint is as follows:

<math> <mrow> <mi>Y</mi> <mo>=</mo> <msqrt> <msup> <mrow> <mi>Dist</mi> <mn>1</mn> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup> <mrow> <mi>Dist</mi> <mn>2</mn> </mrow> <mn>2</mn> </msup> <mo>-</mo> <mn>2</mn> <mo>&times;</mo> <mi>Dist</mi> <mn>1</mn> <mo>&times;</mo> <mi>Dist</mi> <mn>2</mn> <mo>&times;</mo> <mi>cos</mi> <mrow> <mo>(</mo> <msub> <mi>&theta;</mi> <mi>init</mi> </msub> <mo>-</mo> <mi>&theta;</mi> <mo>)</mo> </mrow> </msqrt> </mrow> </math>

in the formula: theta_initIs the initial angle value of the knee joint when the human body stands still and upright, and Dist1 is the distance between the connecting point of the hydraulic cylinder on the thigh part and the knee joint; dist2 is the distance between the connection point of the hydraulic cylinder on the lower leg part and the knee joint;

a preset relation K in the amplifier module_aComprises the following steps:

$K_a=\frac{I}{U_{\mathrm{ctrl}}}$

in the formula: k_aIs an amplification gain constant;

a preset relational expression G in the hydraulic adjusting module_svComprises the following steps:

<math> <mrow> <msub> <mi>G</mi> <mi>sv</mi> </msub> <mo>=</mo> <mfrac> <msub> <mi>x</mi> <mi>v</mi> </msub> <mi>I</mi> </mfrac> <mo>=</mo> <mfrac> <msub> <mi>K</mi> <mi>sv</mi> </msub> <mrow> <mfrac> <msup> <mi>s</mi> <mn>2</mn> </msup> <msup> <msub> <mi>&omega;</mi> <mi>sv</mi> </msub> <mn>2</mn> </msup> </mfrac> <mo>+</mo> <mfrac> <msub> <mrow> <mn>2</mn> <mi>&xi;</mi> </mrow> <mi>sv</mi> </msub> <msub> <mi>&omega;</mi> <mi>sv</mi> </msub> </mfrac> <mi>s</mi> <mo>+</mo> <mn>1</mn> </mrow> </mfrac> </mrow> </math>

in the formula: omega_svIs the natural frequency, ξ, of the servo valve_svIs the damping ratio of the servo valve, K_svIs the gain constant of the servo valve;

an equivalent mathematical model G preset in the equivalent module of the actuator_eqComprises the following steps:

<math> <mrow> <msub> <mi>G</mi> <mi>eq</mi> </msub> <mo>=</mo> <mfrac> <mfrac> <msub> <mi>K</mi> <mi>q</mi> </msub> <msub> <mi>A</mi> <mi>p</mi> </msub> </mfrac> <mrow> <mfrac> <mrow> <msub> <mi>V</mi> <mi>t</mi> </msub> <msub> <mi>m</mi> <mi>t</mi> </msub> </mrow> <mrow> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mrow> </mfrac> <msup> <mi>s</mi> <mn>3</mn> </msup> <mo>+</mo> <mrow> <mo>(</mo> <mfrac> <mrow> <msub> <mi>m</mi> <mi>t</mi> </msub> <msub> <mi>K</mi> <mi>ce</mi> </msub> </mrow> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>+</mo> <mfrac> <mrow> <msub> <mi>B</mi> <mi>e</mi> </msub> <msub> <mi>V</mi> <mi>t</mi> </msub> </mrow> <mrow> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mrow> </mfrac> <mo>)</mo> </mrow> <msup> <mi>s</mi> <mn>2</mn> </msup> <mo>+</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mfrac> <mrow> <msub> <mi>B</mi> <mi>e</mi> </msub> <msub> <mi>K</mi> <mi>ce</mi> </msub> </mrow> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>+</mo> <mfrac> <msub> <mi>KK</mi> <mi>ce</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> <mo>)</mo> </mrow> <mi>s</mi> <mo>+</mo> <mfrac> <msub> <mi>KK</mi> <mi>ce</mi> </msub> <msubsup> <mi>A</mi> <mi>p</mi> <mn>2</mn> </msubsup> </mfrac> </mrow> </mfrac> </mrow> </math>

in the formula: m is_tIs the mass of the shank part of said rigid limb, B_eIs the damping of said rigid limbs, beta_eIs the modulus of elasticity, K, of the hydraulic oil in the hydraulic cylinder_ceIs the total flow-pressure coefficient of the servo valve, K is the spring rate of the rigid body, K_qIs the flow gain of the servo valve, A_pIs the effective area, V, of the piston rod_tIs the total volume of the hydraulic cylinder;

an equivalent mathematical model G preset in the supporting load compensation module_compComprises the following steps:

G_comp＝G_YtoFG_FtoFK

wherein,

<math> <mrow> <msub> <mi>G</mi> <mi>FtoFK</mi> </msub> <mo>=</mo> <mfrac> <mn>1</mn> <mrow> <msub> <mi>K</mi> <mi>q</mi> </msub> <msub> <mi>A</mi> <mi>p</mi> </msub> </mrow> </mfrac> <mrow> <mo>(</mo> <msub> <mi>K</mi> <mi>ce</mi> </msub> <mo>+</mo> <mfrac> <msub> <mi>V</mi> <mi>t</mi> </msub> <msub> <mrow> <mn>4</mn> <mi>&beta;</mi> </mrow> <mi>e</mi> </msub> </mfrac> <mi>s</mi> <mo>)</mo> </mrow> </mrow> </math>

$G_{\mathrm{YtoF}}=\frac{F_{\mathrm{comp}}}{Y_{\mathrm{need}}}.$

6. the apparatus of claim 5, wherein the portable device comprises: selecting G in the following range according to the gait obtained by the gait judging module_YtoFThe value of (c):

0≤G_YtoF≤1866

wherein, when the walking swing of one leg is performed, G_YtoF＝0。

7. The method for controlling a human-computer coupled heavy-duty carrying system according to any one of claims 1 to 6, comprising the steps of:

1) a hydraulic cylinder is arranged on a thigh part of a rigid limb of the man-machine coupling heavy-load carrying system, a piston rod of the hydraulic cylinder is connected with the thigh part of the rigid limb, and a circle of flange is arranged at the inner end of the piston rod to divide the hydraulic cylinder into a hydraulic cavity and a gas energy storage cavity; meanwhile, a sole pressure sensor and a knee joint angle sensor corresponding to a human body are arranged in a control system of the rigid body, and a gait judging module, an actuator position calculating module, a controller module, an amplifier module, a hydraulic adjusting module, an actuator equivalent module, a supporting load compensation module and two adders are arranged on a control board card;

2) the sole pressure sensor acquires sole pressure information, and the knee joint angle sensor acquires knee joint rotation angle information;

3) the gait judging module compares and judges the obtained plantar pressure sensor signal with a preset threshold value in the gait judging module, and selects one of the following three control instructions to execute according to a judging result:

firstly, when the walking support is in a single-leg walking support state, executing a position closed-loop control instruction and a force closed-loop control instruction, and entering a step 4);

executing a position closed-loop control instruction when the two legs are in static support, and entering the step 5);

thirdly, when the user walks and swings with one leg, executing a gradual change open-loop control instruction, and entering the step 6);

4) the actuator position calculation module obtains the knee joint angle expected change value theta output by the knee joint angle sensor_expAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the expected position Y of the piston rod_expAnd output to the adder;

the actuator position calculation module obtains the actual change value theta of the knee joint angle output by the knee joint angle sensor_sensorAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the actual position Y of the piston rod_actAnd output to the adder;

the adder obtains the expected position Y of the piston rod_expAnd the actual position Y_actSubtracting, and outputting the calculated deviation value to the controller module;

the other adder subtracts the obtained sole pressure sensor signal from a sole expected signal value preset in the control system and outputs the calculated deviation value to the controller module;

the controller module obtains the expected position Y of the piston rod according to the obtained expected position_expAnd the actual position Y_actAnd the deviation of the sole pressure sensor signal from the sole expected signal value, and a mathematical model expression G of a PID controller preset in the mathematical model expression G_PIDCalculating the voltage control signal U_ctrlAnd outputs it to the amplifier module, and proceeds to step 7);

5) the piston rod is arranged at a desired position Y_expIs set as the maximum value Y of the output position of the piston rod of the actuator when a person is in a two-leg static supporting state_maxAnd output to the adder;

the actuator position calculation module obtains the actual change value theta of the knee joint angle output by the knee joint angle sensor_sensorAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the actual position Y of the piston rod_actAnd output to the adder;

the adder will get the activityDesired position Y of the stopper rod_expAnd the actual position Y_actSubtracting, and outputting the calculated deviation value to the controller module;

the controller module obtains the expected position Y of the piston rod according to the obtained expected position_expAnd the actual position Y_actAnd a mathematical model expression G of a PID controller preset in the deviation value_PIDCalculating the voltage control signal U_ctrlAnd outputs it to the amplifier module, and proceeds to step 7);

6) the actuator position calculation module obtains the knee joint angle expected change value theta output by the knee joint angle sensor_expAnd a relation between the position Y of the piston rod preset in the position Y and the angle change value theta of the knee joint, and calculating the expected position Y of the piston rod_expAnd output to the adder;

the adder obtains the expected position Y of the piston rod_expDirectly outputting the data to a controller module;

the controller module obtains the expected position Y of the piston rod according to the obtained expected position_expAnd a mathematical model expression G of a PID controller preset therein_PIDCalculating the voltage control signal U_ctrlAnd outputs it to the amplifier module;

7) the amplifier module passes through a preset relational expression K in the amplifier module_aThe obtained voltage control signal U_ctrlConverting the current into a servo current amount I and outputting the servo current amount I to a hydraulic adjusting module;

8) the hydraulic adjusting module passes through a relation G preset in the hydraulic adjusting module_svConverting the obtained servo current I into the opening size x of the servo valve_vAnd output it to the equivalent module of the actuator;

9) the equivalent module of the actuator is expressed by an equivalent mathematical model expression G preset in the equivalent module_eqThe obtained opening size x of the servo valve_vAnd a supporting load compensation force F fed back by the supporting load compensation module_compConversion into the position Y to be output by the piston rod_needAnd outputs it to the supporting load compensation module;

10) the supporting load compensation module passes through an equivalent mathematical model G preset in the supporting load compensation module_compThe piston rod shouldPosition Y of the output_needSupporting load compensation force F converted into piston rod output_compAnd feeding back the data to the equivalent module of the actuator, and returning to the step 2) until the control system sends an instruction to finish the circulation.

8. The method of claim 7, wherein the method further comprises: in the step 4), a sole expected signal preset in the control system and a preassigned sole expected supporting force F_expCorrespondingly, the desired supporting force F of the sole_expIs the sum of the weight of the heavy load and the weight of the heavy load carrying system device after the weight of the human body is deducted.

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