Driving method, device, storage medium and processor of mechanical exoskeleton

Abstract

The application discloses a driving method and device of a mechanical exoskeleton, a storage medium and a processor. The method comprises the following steps: based on current position information of an actuator, a target motor generates a driving signal; based on the driving signal, a hydraulic valve generates a hydraulic signal; and based on the hydraulic signal, the hydraulic valve controls the motion state of the actuator, so as to adjust the position information of the actuator from the current position information to target position information, wherein the position information of the actuator is used to control the joint of the mechanical exoskeleton to move. The application solves the technical problem of low safety of the mechanical exoskeleton in use.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of exoskeleton driving, and in particular, to a driving method and device of a mechanical exoskeleton, a storage medium and a processor. BACKGROUND

[0002] At present, the exoskeleton applied to physical enhancement as a wearable mechanical device with strong functions has been paid more and more attention by domestic and foreign scholars and researchers, has become a new research hotspot, and is gradually applied to the military field. However, the existing mechanical exoskeleton driving system has large volume and weight, and the driving oil circuit is also relatively complex, thereby causing safety problems of the mechanical exoskeleton in the use process.

[0003] At present, no effective solution has been proposed for the technical problem of low safety of the mechanical exoskeleton in the use process. SUMMARY

[0004] The present disclosure provides a driving method and device of a mechanical exoskeleton, a storage medium and a processor to at least solve the technical problem of low safety of the mechanical exoskeleton in the use process.

[0005] According to an aspect of an embodiment of the present disclosure, a driving method of a mechanical exoskeleton is provided. The method can include: controlling a target motor to generate a driving signal based on current position information of an actuator; generating a hydraulic signal for a hydraulic valve based on the driving signal; and controlling the hydraulic valve to control a motion state of the actuator based on the hydraulic signal to adjust the position information of the actuator from the current position information to target position information, wherein the position information of the actuator is used to control a joint of the mechanical exoskeleton to move.

[0006] Optionally, generating the hydraulic signal for the hydraulic valve based on the driving signal includes: driving a hydraulic pump to generate the hydraulic signal for the hydraulic valve based on the driving signal.

[0007] Optionally, controlling the hydraulic valve to control the motion state of the actuator based on the hydraulic signal includes: controlling a target speed and a target torque of the actuator motion based on the hydraulic signal, wherein the target speed and the target torque are in an inverse relationship.

[0008] Optionally, the back electromotive force of the stator phase winding when the target motor rotates is determined based on a trapezoidal wave function, wherein a waveform of the trapezoidal wave function is consistent with an air gap magnetic field waveform of the target motor; the stator phase winding voltage of the target motor is determined based on the back electromotive force; and the driving signal of the target motor is generated by controlling the target motor to generate the driving signal based on the stator phase winding voltage.

[0009] Optionally, the counter electromotive force of the stator phase winding of the target motor during rotation of the target motor is determined based on the trapezoidal wave function, the flux linkage of the target motor, and the angular velocity of the rotor of the target motor.

[0010] Optionally, the trapezoidal wave function is determined based on the electromagnetic torque of the target motor.

[0011] Optionally, the stator phase winding voltage of the target motor is determined based on the counter electromotive force, the stator phase winding resistance of the target motor, and the stator phase winding current.

[0012] Optionally, the three-phase Hall signals of the target motor are determined based on the target variable of the trapezoidal wave function, the target variable being determined by a target phase angle of the target motor, and the three-phase Hall signals being signals of three-phase Hall effect sensors of the target motor.

[0013] Optionally, when a first Hall signal of the three-phase Hall signals is determined to have a phase abnormality, a phase of a second Hall signal of the three-phase Hall signals that has a normal phase is delayed to obtain a third Hall signal, and the first Hall signal is reconstructed based on the third Hall signal.

[0014] Optionally, delaying the phase of the second Hall signal of the three-phase Hall signals that has the normal phase to obtain the third Hall signal includes delaying the phase of the second Hall signal by a target electrical angle to obtain the third Hall signal, the target electrical angle being used to represent a difference angle between the three-phase Hall signals.

[0015] According to another aspect of the embodiments of the present disclosure, a driving device of a mechanical exoskeleton is also provided. The device can include a first control unit configured to control a target motor to generate a driving signal based on current position information of an actuator; a generation unit configured to generate a hydraulic signal for a hydraulic valve based on the driving signal; and a second control unit configured to control the hydraulic valve to control a movement state of the actuator based on the hydraulic signal, so as to adjust the position information of the actuator from the current position information to target position information, wherein the position information of the actuator is used to control a joint of the mechanical exoskeleton to move.

[0016] According to another aspect of the embodiments of the present disclosure, a computer readable storage medium is also provided. The computer readable storage medium includes a stored program, wherein the program, when executed by a processor, controls a device in which the computer readable storage medium is located to perform the control method of the rope according to the embodiments of the present disclosure.

[0017] According to another aspect of the embodiments of the present disclosure, a processor is also provided. The processor is configured to execute a program, wherein the program, when executed, performs the control method of the rope according to the embodiments of the present disclosure.

[0018] In the embodiment of the present disclosure, based on the current position information of the actuator, a control target motor generates a driving signal; based on the driving signal, a hydraulic valve generates a hydraulic signal; based on the hydraulic signal, the hydraulic valve controls the motion state of the actuator to adjust the position information of the actuator from the current position information to the target position information, wherein the position information of the actuator is used to control the joint of the mechanical exoskeleton to move. That is, first, the driving signal is generated according to the current position information of the actuator, and then the hydraulic signal is generated based on the driving signal, so as to control the motion state of the actuator, and then adjust the actuator from the current position to the target position, thereby solving the technical problem of low safety of the mechanical exoskeleton in use, and achieving the technical effect of improving the safety of the mechanical exoskeleton in use. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings described herein are used to provide further understanding of the present disclosure, and form a part of the present application. The illustrative embodiments of the present disclosure and their descriptions serve to explain the present disclosure, and do not constitute an improper limitation on the present disclosure. In the drawings:

[0020] Figure 1 is a flow chart of a lower limb exoskeleton driving method according to an embodiment of the present disclosure;

[0021] Figure 2 is a structural block diagram of an exoskeleton driving system according to an embodiment of the present disclosure;

[0022] Figure 3 is a schematic diagram of a lower limb exoskeleton hydraulic driving system according to an embodiment of the present disclosure;

[0023] Figure 4 is a structural diagram of a lower limb exoskeleton hydraulic system according to an embodiment of the present disclosure;

[0024] Figure 5 is an equivalent circuit diagram of a brushless direct current motor according to an embodiment of the present disclosure;

[0025] Figure 6 is a waveform diagram of a trapezoidal wave function according to an embodiment of the present disclosure;

[0026] Figure 7 is a signal waveform diagram of a rotating electrical period three-phase Hall effect sensor according to an embodiment of the present disclosure;

[0027] Figure 8 is a waveform diagram of Hall fault detection and identification according to an embodiment of the present disclosure;

[0028] Figure 9 is a Hall signal reconstruction waveform diagram when Hall phase A fails according to an embodiment of the present disclosure;

[0029] Fig. 10(a) is a speed diagram of a simulation output according to an embodiment of the present disclosure;

[0030] Fig. 10(b) is a torque output diagram according to an embodiment of the present disclosure;

[0031] Fig. 10(c) is a phase current diagram according to an embodiment of the present disclosure;

[0032] Fig. 10(d) is a back electromotive force waveform diagram according to an embodiment of the present disclosure;

[0033] Figure 11 Fig. 11 is a schematic diagram of a driving device of a mechanical exoskeleton according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] In order to make the personnel in the technical field better understand the present disclosure scheme, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, not all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present disclosure.

[0035] It should be noted that the terms "first", "second", and the like in the specification and claims of the present disclosure and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or a chronological order. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0036] Embodiment 1

[0037] According to an embodiment of the present disclosure, an embodiment of a driving method of a mechanical exoskeleton is provided.

[0038] The steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown herein.

[0039] Figure 1 Fig. 12 is a flowchart of a driving method of a mechanical exoskeleton according to an embodiment of the present disclosure. As shown in Fig. 12, the driving method of the mechanical exoskeleton according to the present embodiment includes the following steps. Figure 1As shown, the method can include the following steps:

[0040] In step S102, a target motor is controlled to generate a driving signal based on current position information of an actuator.

[0041] In the technical solution provided by the above step S102 of the disclosure, the actuator is used to be controlled by the hydraulic signal, and the joint of the mechanical exoskeleton is controlled to move, which can include a hip joint hydraulic cylinder and a knee joint hydraulic cylinder, the target motor is a direct current motor, and the driving signal can include extension or retraction of the hip joint and the knee joint.

[0042] Optionally, the direct current motor can automatically determine whether the next action is extension or retraction according to the position information of the lower extremity exoskeleton currently located.

[0043] In step S104, a hydraulic signal is generated for a hydraulic valve based on the driving signal.

[0044] In the technical solution provided by the above step S104 of the disclosure, the direct current motor drives a micro hydraulic pump to provide hydraulic power for the exoskeleton, and the hydraulic valve realizes logical control for the exoskeleton driving system according to the received driving signal, wherein the hydraulic signal is the extension or retraction of the hip joint and the knee joint hydraulic cylinder.

[0045] For example, the entire hydraulic driving system is divided into two hydraulic circuits according to the driving of the left leg and the right leg, and the high-pressure oil generated by the gear pump driven by the direct current motor can directly drive the extension of the hip joint and the knee joint hydraulic cylinder after passing through the check valve, while the retraction of the hip joint and the knee joint hydraulic cylinder is controlled by the normally closed electromagnetic valve.

[0046] In step S106, the movement state of the actuator is controlled by the hydraulic valve based on the hydraulic signal to adjust the position information of the actuator from the current position information to the target position information, wherein the position information of the actuator is used to control the joint of the mechanical exoskeleton to move.

[0047] In the technical solution provided by the above step S106 of the disclosure, the hydraulic valve controls the extension or retraction of the hip joint and the knee joint hydraulic cylinder according to the hydraulic signal, thereby controlling the movement state of the lower extremity exoskeleton, wherein the movement state can include forward movement or backward movement, which is not limited here.

[0048] By the steps S102 to S106, the target motor generates the driving signal based on the current position information of the actuator, the hydraulic signal is generated for the hydraulic valve based on the driving signal, and the motion state of the actuator is controlled by the hydraulic valve based on the hydraulic signal, so as to adjust the position information of the actuator from the current position information to the target position information, wherein the position information of the actuator is used to control the joint of the mechanical exoskeleton to move. That is, the driving signal is first generated according to the current position information of the actuator, and then the hydraulic signal is generated based on the driving signal, so as to control the motion state of the actuator, and then the actuator is adjusted from the current position to the target position, thereby solving the technical problem of low safety of the mechanical exoskeleton in use, and achieving the technical effect of improving the safety of the mechanical exoskeleton in use.

[0049] The above method of the embodiment will be further introduced below.

[0050] As an optional implementation, in step S104, the hydraulic signal is generated for the hydraulic valve based on the driving signal, including: driving the hydraulic pump to generate the hydraulic signal for the hydraulic valve based on the driving signal.

[0051] In this embodiment, the hydraulic valve drives the hydraulic pump to realize logical control of the exoskeleton driving system according to the received driving signal, wherein the hydraulic signal is the elongation or retraction of the hydraulic cylinders of the hip joint and the knee joint.

[0052] As an optional implementation, in step S106, the motion state of the actuator is controlled by the hydraulic valve based on the hydraulic signal, including: controlling the target speed and the target torque of the actuator motion based on the hydraulic signal, wherein the target speed and the target torque are in inverse proportional relationship.

[0053] In this embodiment, the target speed is the flow of the actuator, and the target torque is the oil pressure of the actuator. The hydraulic and flow characteristics of the driving system belong to a dynamic problem, and the relationship between the speed and the torque of the actuator needs to be balanced by the hydraulic control valve to ensure that there is enough torque to drive the exoskeleton to move at the desired speed.

[0054] As an optional implementation, in step S106, the counter electromotive force of the stator phase winding when the target motor rotates is determined based on the trapezoidal wave function, wherein the waveform of the trapezoidal wave function is consistent with the air gap magnetic field waveform of the target motor; the stator phase winding voltage of the target motor is determined based on the counter electromotive force; and the driving signal of the target motor is generated, including: the driving signal of the target motor is generated based on the stator phase winding voltage.

[0055] In this embodiment, the trapezoidal wave function can be modeled by finite element analysis, Fourier transform or piecewise linear method. The first two modeling methods have high simulation accuracy, but the calculation amount is large, which will significantly reduce the simulation speed. In contrast, the piecewise linear method is simple to calculate, and the accuracy can meet the simulation requirements. Therefore, the piecewise linear method is used to establish the trapezoidal wave function in this embodiment to obtain the back electromotive force, so as to determine the stator phase winding voltage of the target motor during rotation, and generate the driving signal.

[0056] As an optional implementation, the back electromotive force of the stator phase winding of the target motor during rotation is determined based on the trapezoidal wave function, including: determining the back electromotive force based on the trapezoidal wave function, the flux linkage of the target motor and the angular velocity of the rotor of the target motor.

[0057] In this embodiment, the flux linkage of the target motor and the angular velocity of the rotor of the target motor can be obtained according to the Kirchhoff's current law and Newton's second law, so as to obtain the back electromotive force of the stator phase winding of the target motor during rotation, and the back electromotive force of the stator phase winding and the stator phase winding voltage satisfy the three-phase winding voltage balance equation of the brushless direct current motor.

[0058] As an optional implementation, the trapezoidal wave function is determined based on the electromagnetic torque of the target motor.

[0059] In this embodiment, the electromagnetic torque of the target motor is determined according to the periodicity of the waveform of the back electromotive force, and then the trapezoidal wave function is determined.

[0060] As an optional implementation, the stator phase winding voltage of the target motor is determined based on the back electromotive force, including: determining the stator phase winding voltage based on the stator phase winding resistance of the target motor, the stator phase winding current and the back electromotive force.

[0061] In this embodiment, the back electromotive force of the stator phase winding and the stator phase winding voltage satisfy the three-phase winding voltage balance equation of the brushless direct current motor, and the three-phase winding voltage balance equation of the brushless direct current motor can be expressed as:

[0062]

[0063] wherein, , , is the stator phase winding voltage; is the stator phase winding resistance; , , is the stator phase winding current; , , is the back electromotive force of the stator phase winding; is the self-induced electromotive force; For the mutual inductance coefficient.

[0064] Optionally, the stator phase winding voltage is determined according to the three-phase winding voltage balance equation of the brushless direct current motor and the counter electromotive force of the stator phase winding.

[0065] As an optional implementation, the three-phase Hall signals of the target motor are determined based on a target variable determined by a target phase angle of the target motor, and the three-phase Hall signals are signals of three-phase Hall effect sensors of the target motor.

[0066] In this embodiment, the installation position of the Hall effect sensor affects the phase difference of the Hall signals of the brushless direct current motor and the 0 position of the rotor electrical angle, so the modeling process needs to assume that the installation position of the Hall effect sensor is correct in advance.

[0067] As an optional implementation, when a first Hall signal with a phase abnormality is determined in the three-phase Hall signals, the phase of a second Hall signal with a normal phase in the three-phase Hall signals is delayed to obtain a third Hall signal; and the first Hall signal is reconstructed based on the third Hall signal.

[0068] In this embodiment, when at least two Hall effect sensors are working normally, the Hall signal of the exoskeleton power supply unit is reconstructed to realize single Hall sensor fault-tolerant control, wherein the single-phase Hall fault-tolerant control is based on speed estimation and signal delay, so the signal reconstruction time is affected by the motor speed estimation accuracy and the motor inertia.

[0069] As an optional implementation, the phase of the second Hall signal with a normal phase in the three-phase Hall signals is delayed to obtain a third Hall signal, including: delaying the phase of the second Hall signal by a target electrical angle to obtain the third Hall signal, wherein the target electrical angle is used to represent the difference angle between the three-phase Hall signals.

[0070] In this embodiment, when at least two Hall sensors are working normally, the signal delay and reconstruction can be used to realize Hall fault-tolerant control according to the feature that the three-phase Hall signals are separated by 120 degrees of electrical angle.

[0071] In the embodiment of the present disclosure, based on the current position information of the actuator, a control target motor generates a driving signal; based on the driving signal, a hydraulic valve generates a hydraulic signal; based on the hydraulic signal, the hydraulic valve controls the motion state of the actuator to adjust the position information of the actuator from the current position information to the target position information, wherein the position information of the actuator is used to control the joint of the mechanical exoskeleton to move. That is, first, the driving signal is generated according to the current position information of the actuator, and then the hydraulic signal is generated based on the driving signal, so as to control the motion state of the actuator, and then adjust the actuator from the current position to the target position, thereby solving the technical problem of low safety of the mechanical exoskeleton in use, and achieving the technical effect of improving the safety of the mechanical exoskeleton in use.

[0072] Embodiment 2

[0073] The technical solutions of the embodiments of the present disclosure will be illustrated below in combination with preferred embodiments.

[0074] It is of great significance to study the lower limb exoskeleton with the main design goal of enhancing the body's load-carrying capacity and reducing the body's metabolic consumption, aiming at individual operation, especially the urgent application needs of individual operation in complex environments such as high cold and high altitude.

[0075] The term "exoskeleton" comes from the hard shell of insects and shellfish in biology. The "exoskeleton" mainly provides protection and support functions for insects and shellfish. The "human mechanical exoskeleton system" is a device worn on the outside of the operator's body, which provides the wearer with body support, protection and other functions, and also provides the wearer with additional power or ability, enhances human function, and enables the wearer to complete certain difficult functions and tasks.

[0076] The lower limb exoskeleton is a human load-assisting device, which mainly designs an external support for the wearer according to the idea of bionics, amplifies the wearer's limb movement while transmitting the weight of the external device to the ground, and achieves both enhanced work capacity and maintained mobility. It is not restricted by road conditions, weather environment, operation time and space. The anthropomorphic structure design can make the exoskeleton and the user's limbs move in coordination, the weight is transferred to the legs and the ground through the exoskeleton skeleton, and the wearer feels only 40% or even lower of the actual weight, thereby greatly reducing the physical consumption of the wearer, enabling the wearer to maintain sufficient physical energy after high-intensity work, and improving work efficiency.

[0077] Since the lower extremity exoskeleton is designed to help human beings walk with load, enhance walking ability and speed, and reduce fatigue after long-distance walking with load, it can be widely applied to civil fields such as rescue and disaster relief, climbing, building and industrial assistance.

[0078] The lower extremity exoskeleton needs to realize human body assistance. In the support phase, the "rigidity" needs to be embodied to support the human body, and in the swing phase, the load does not interfere with the normal walking of the human body, so as to achieve the minimum human-machine interaction force. Both have obvious different functional requirements and have the essential connection of "the same mechanical structure".

[0079] The existing mechanical exoskeleton driving system has large volume and weight, and the driving oil circuit is also relatively complex, thereby causing safety problems of the mechanical exoskeleton in the use process.

[0080] However, the application provides a driving method of the mechanical exoskeleton, which can ensure normal operation of the motor by increasing a fault-tolerant control module of the motor, thereby improving reliability and safety of the mechanical exoskeleton.

[0081] In the embodiment, a structure block diagram of an exoskeleton driving system is provided, as shown in Figure 2 , and Figure 2 is a structure block diagram of an exoskeleton driving system according to an embodiment of the present disclosure. The load motor type exoskeleton of the embodiment uses a battery-hydraulic power mode, adopts a lithium battery (the battery is a lithium battery) as an energy source, provides hydraulic power for the exoskeleton through a direct-current motor driving micro hydraulic pump, realizes logic control through a hydraulic valve, and uses a hip joint hydraulic cylinder and a knee joint hydraulic cylinder as an actuator, thereby realizing control of lower limb joint movement.

[0082] In the embodiment, a principle diagram of a lower extremity exoskeleton hydraulic driving system is also provided, as shown in Figure 3 , and Figure 3 is a principle diagram of a lower extremity exoskeleton hydraulic driving system according to an embodiment of the present disclosure. The lower extremity exoskeleton hydraulic driving system comprises a closed oil bag 301, a first three-way joint 302, a first hydraulic pipe type overflow valve (YF-L8H1-S) 303, a first electric gear pump 304, a first one-way valve 305, a normally closed two-way electromagnetic valve 306, a first four-way joint 307, a first oil cylinder (1670) 308, an M6 inner oil cylinder (1430) 309, a second three-way joint 310, a second hydraulic pipe type overflow valve (YF-L8H1-S) 311, a second electric gear pump 312, a second one-way valve 313, a normally open two-way electromagnetic valve 314, a second four-way joint 315, a second oil cylinder (1670) 316, and an oil cylinder (1430) 317.

[0083] In the lower limb exoskeleton hydraulic drive system of the embodiment, the entire hydraulic drive system is divided into two hydraulic circuits according to the drive of the left leg and the right leg. The high-pressure oil liquid generated by the gear pump driven by the DC motor can directly drive the hip joint and the knee joint hydraulic cylinder to extend after passing through the check valve. The input oil pressure and flow of the two cylinders are directly controlled by the motor, and the retraction of the two cylinders is controlled by the normally closed electromagnetic valve. The drive oil path of the joint hydraulic cylinder in the actuator is connected by parallel connection. In the design of the joint hydraulic cylinder, the single-acting oil cylinder (active in the extension direction and passive in the retraction direction) is used in the hip joint hydraulic cylinder and the knee joint hydraulic cylinder in the wearable hydraulic system of the disclosure, and the phase conversion and flow control of each cylinder are performed through the hydraulic control valve, so that the control of the joint movement is realized.

[0084] Optionally, the hydraulic circuit of the lower limb exoskeleton is a closed system as a whole, that is, the flow passages of various hydraulic elements such as pipes, joints, valve blocks, actuators, pump bodies in the circuit form a closed cavity as a whole, and the hydraulic medium does not contact with air. The closed system can prevent the hydraulic medium from being polluted by solid particles and moisture from air, and avoid air mixing into the hydraulic medium to reduce the elastic modulus thereof.

[0085] Optionally, the structure of the hydraulic system of the lower limb exoskeleton is as shown in Figure 4 Figure 4 is a structure diagram of a lower limb exoskeleton hydraulic system according to the embodiment of the disclosure. The structure of the lower limb exoskeleton hydraulic system can include: PA (nylon) hose 401, two-position two-way normally closed high-pressure electromagnetic valve 402, hip joint hydraulic cylinder 403, sealed oil bag 404, gear pump 405, DC motor 406, hydraulic pipe type overflow valve 407, pressure gauge 408, high-pressure hose 409, knee joint hydraulic cylinder 410.

[0086] In the lower limb exoskeleton hydraulic system of the embodiment, the hydraulic pumps, hydraulic cylinders, reversing valves, pressure gauges and other hydraulic elements of the two routes are integrated into a micro hydraulic station. Two hydraulic pipes are respectively extended in the hydraulic station for driving the hip joint hydraulic cylinder and the knee joint hydraulic cylinder. The oil return pipe and the oil inlet pipe of the two cylinders share the same hydraulic pipe. The hydraulic pump used in the hydraulic system is a high-speed gear pump, which can reach a working speed of 10000 rpm. The pump can be directly driven by the motor, reducing the transmission and speed change mechanism between the motor and the hydraulic pump, and reducing the overall weight and space occupation. At the same time, high speed also has the characteristics of small volume and light weight, which is a key element to realize a high-power density drive system.

[0087] Optionally, the working parameters of the hydraulic pump are determined by factors such as torque matching of the motor, working efficiency, and the like. The specific parameters are shown in Table 1, which is a parameter design table of a lower limb exoskeleton hydraulic drive system according to the embodiment of the disclosure.

[0088] Table 1 Parameter design table of lower limb exoskeleton hydraulic drive system​

[0089]

[0090] The main difficulty in the design of the exoskeleton drive system actuator is to select the actuator size and mounting position so that the joint torque output by the actuator always exceeds the torque required by the exoskeleton. However, when the output torque of the actuator exceeds the required joint torque too much, it will result in low system efficiency and increased energy loss. Therefore, the design of the actuator needs to consider the relationship between the peak torque size and its power efficiency.

[0091] The design of the hydraulic actuator solves the static calculation problem of the exoskeleton drive system, while the hydraulic and flow characteristics of the drive system are dynamic problems that need to be solved through the calculation of the hydraulic control valve. The flow transmitted to the actuator is inversely proportional to the oil pressure, so the control valve is needed to balance the relationship between the actuator output speed (flow) and torque (oil pressure) to ensure that at the desired speed, there is enough torque to drive the exoskeleton to walk.

[0092] As an optional embodiment, a direct current motor modeling and fault-tolerant control optimization method is proposed, which mainly includes the following parts:

[0093] The first part is the modeling of the direct current motor.

[0094] In order to simplify the motor model and ensure the accuracy of the actual engineering application, the following six assumptions need to be made before modeling the brushless direct current motor:

[0095] (1) The three-phase winding space is uniform and completely symmetrical;

[0096] (2) The three-phase Hall is uniformly spaced at 120 degrees;

[0097] (3) The air gap magnetic field waveform is an ideal trapezoidal wave;

[0098] (4) Ignore the effects of motor tooth slot effect, armature reaction and commutation process

[0099] (5) Ignore the magnetic saturation effect of the motor;

[0100] (6) Ignore the hysteresis loss and eddy current loss of the motor.

[0101] After modeling the brushless direct current motor, its equivalent circuit diagram is as shown in Figure 5 , Figure 5 is an equivalent circuit diagram of a brushless direct current motor according to an embodiment of the disclosure. According to the electric vector direction and motor protocol shown in Figure 5 , the three-phase winding voltage balance equation of the brushless direct current motor can be expressed as:

[0102]

[0103] wherein, , , may be used to represent the stator phase winding voltage; may be used to represent the stator phase winding resistance; , , is the stator phase winding current; , , is the back electromotive force of the stator phase winding; is the self-induced electromotive force; is the mutual inductance coefficient.

[0104] According to Kirchhoff's current law, the three-phase currents of the star-connected brushless DC motor satisfy:

[0105]

[0106] For a three-phase symmetrical synchronous motor, if only the fundamental component of the motor back electromotive force is considered, then:

[0107]

[0108] According to Newton's second law, the kinematic equation can be expressed as:

[0109]

[0110]

[0111]

[0112] wherein, is the electromagnetic torque of the motor; is the damping constant; is the moment of inertia; is the load torque; is the mechanical angular velocity of the rotor; is the electrical angle of the rotor; is the mechanical angle of the rotor; is the number of rotors.

[0113] The relationship between the motor output torque equation and the rotor angular velocity can be expressed as:

[0114]

[0115] The back electromotive force generated by the stator phase winding when the motor rotates can be expressed as:

[0116]

[0117]

[0118]

[0119] The waveform of the back electromotive force has periodicity, in order to facilitate the generalization of the waveform function, the variable can be expressed as:

[0120]

[0121] wherein, is a trapezoidal wave function with an amplitude of 1, and the waveform is consistent with the air gap magnetic field; is the magnetic linkage; is the remaining electrical angle stage Divided by , and b stage leads a stage by 120° phase angle, and a stage leads c stage by 120° phase angle; is the first stage phase angle of stage .

[0122] Optionally, in this embodiment, for the trapezoidal wave function can be explained as follows.

[0123] The trapezoidal wave function can be modeled by finite element analysis, Fourier transform or piecewise linear method. The simulation accuracy of the first two modeling methods is high, but the calculation amount is large, which will significantly reduce the simulation speed. In comparison, the piecewise linear method is simple to calculate, and the accuracy can meet the simulation requirements. Therefore, the linear method is used to establish the back electromotive force analysis model. Set , the initial stage of the back electromotive force phase angle is , then . Therefore, can be simplified as , and the trapezoidal wave function is as shown in Figure 6 , and Figure 6 is a trapezoidal wave function waveform diagram according to an embodiment of the disclosure, and the trapezoidal wave function can be expressed as:

[0124]

[0125] The trapezoidal wave functions corresponding to the b-phase winding and the c-phase winding can be expressed as:

[0126]

[0127]

[0128] Second part, Hall sensor modeling.

[0129] The installation position of the Hall effect sensor affects the phase difference of the Hall signal of the brushless DC motor and the 0° position of the rotor electrical angle, so the modeling process needs to assume that the installation position of the Hall effect sensor is correct in advance. Therefore, the change of the signal waveform of the three-phase Hall effect sensor of the motor in one rotating electrical cycle can be expressed as Figure 7 , Figure 7 is a rotating electrical cycle three-phase Hall effect sensor signal waveform diagram according to an embodiment of the disclosure.

[0130] The relationship between the Hall signal and the remaining electrical angle stage divided by ) can be expressed by the function , , :

[0131]

[0132]

[0133]

[0134] Part III, fault-tolerant controller design.

[0135] In the case of normal operation of at least two Hall effect sensors, single Hall sensor fault-tolerant control can be achieved by reconstructing the Hall signal of the exoskeleton power supply unit. The key to the design of the Hall fault-tolerant controller is to correctly identify the type of Hall signal failure during the driving rotation process. The detailed fault types are shown in Table 2, which is a Hall fault type table according to an embodiment of the disclosure.

[0136] Table 2 Hall fault type table

[0137]

[0138] Assuming that the brush pole of the DC brushless motor is 2P, under normal circumstances, the three-phase Hall sensor output signal has 6 transitions per pole when the motor is operating normally. Therefore, the Hall signal transition edge number output by the magnetic pole motor 2P can be expressed as:

[0139]

[0140] wherein represents the estimated rotor electrical angular velocity, represents the electrical angle corresponding to the adjacent Hall edge, represents the time interval of adjacent Hall edges.

[0141] According to the electrical difference between the state changes of the three-phase Hall signals of the fault-free Hall is 120° electrical angle, it can be inferred that the Hall signal of the fault phase can be regenerated by delaying the signals of other phases. Thus, the signal reconstruction function can be derived:

[0142]

[0143]

[0144]

[0145] Then the electrical angle The estimated delay time can be represented as:

[0146]

[0147] That is, That is, the motor rotates The estimated time interval of the electrical angle.

[0148] The fourth part is the fault-tolerant control simulation analysis.

[0149] Based on the above research content, the mathematical model of the motor and the fault-tolerant strategy can be simulated and analyzed by using MATLAB / Simulink. In order to better verify the correctness and effectiveness of the model and the fault-tolerant algorithm, the motor parameters used for simulation are shown in Table 3, which is a kind of motor parameters used for simulation according to the embodiment of the present disclosure.

[0150] Table 3 Motor parameters used for simulation

[0151]

[0152] In the fault detection and fault type identification simulation of the fault-tolerant controller, since the Hall fault-tolerant controller is based on the edge of the Hall signal for fault-tolerant control, whether the Hall sensor is working fault or short circuit fault, the fault phenomenon of the Hall fault-tolerant controller is consistent.

[0153] For example, taking the short circuit fault of the Hall sensor as an example, the short circuit faults of the Hall phases A, B and C are set at 1.5s after the simulation starts. The system simulation time is set to 2s, as shown in Figure 8 Figure 8 ​is a Hall fault detection and identification waveform according to an embodiment of the disclosure. As can be seen from the figure, the time interval from the occurrence of the short-circuit fault of Hall phase A to the detection and identification is 0.03 s, the identification time of Hall phase B is 0.04 s, and the identification time of Hall phase C is 0.01 s. The speed of the motor and the time of the fault occurrence will affect the identification time of the fault, and the identification time is the difference between the fault time and the nearest Hall edge time.

[0154] For example, in the fault signal reconstruction simulation of the fault-tolerant controller, taking the short-circuit fault of Hall phase A as an example, the short-circuit fault of Hall phase A is introduced at 1.5 s after the simulation starts, and the simulation waveform is as shown in Figure 9 Figure 9 is a Hall signal reconstruction waveform when Hall phase A fails according to an embodiment of the disclosure. As can be seen from the figure, the time interval from the occurrence of the short-circuit fault of Hall phase A to the reconstruction output is 0.033 s. Since the single-phase Hall fault-tolerant control is based on speed estimation and signal delay, the signal reconstruction time is affected by the accuracy of the motor speed estimation and the motor inertia.

[0155] In the no-load fault-tolerant simulation, the reference speed , the sampling time , the proportional factor , and the integral time constant are set. A constant torque load is added at 1 s after the simulation starts , and Hall phase A is set to fail at 1.5 s after the start. The rotor speed, torque, phase current, and back-EMF of the simulation output are shown in FIG. 10, which is a speed, output torque, phase current, and back-EMF waveform diagram of the simulation output according to an embodiment of the disclosure. As can be seen from the figure, at 1.7 s after the fault occurs, the system returns to normal operation, and the fault-tolerant adjustment time is 0.2 s. During the short-circuit fault of Hall phase A, the speed of the system drops to 160 rpm, and the dynamic torque of the motor also drops to 3.63 Nm. The simulation results show that the Hall fault-tolerant controller can quickly reconstruct the position signal required for motor rotation in the case of a Hall fault, ensuring that the power system continues to operate stably.

[0156] ​In this embodiment, for the power system Hall device fault-tolerant control requirements in the DC motor design of the lower extremity exoskeleton driving system, a dynamic system simulation model is established in the MATLAB\simulink environment, and the characteristics of the model are simulated to verify the correctness of the model. From the simulation results, it can be seen that the model meets the requirements of the motor characteristics. Then a single-phase Hall fault-tolerant control method based on model speed estimation and signal delay is studied. When at least two Hall sensors are working normally, according to the characteristics of the three-phase Hall signal interval of 120 degrees of electrical angle, the signal delay and reconstruction can realize the Hall fault-tolerant control. The simulation results from the fault-tolerant control of the power system show that the Hall fault-tolerant control strategy can quickly and effectively reconstruct the Hall position signal, ignore the error caused by the failure of a single Hall sensor, and ensure the stable operation of the motor control system, thereby controlling the motion state of the actuator, solving the technical problem of low safety of the mechanical exoskeleton in use, and realizing the technical effect of improving the safety of the mechanical exoskeleton in use.

[0157] Embodiment 3

[0158] The embodiment of the present disclosure also provides a driving device of a mechanical exoskeleton. It should be noted that the device of this embodiment can be used to execute the driving method of the mechanical exoskeleton in Embodiment 2 of the present disclosure.

[0159] Figure 11 is a schematic diagram of a driving device of a mechanical exoskeleton according to an embodiment of the present disclosure. As shown in Figure 11 the driving device 1100 of the mechanical exoskeleton can include a first control unit 1101, a generation unit 1102, and a second control unit 1103.

[0160] The first control unit 1101 is configured to control a target motor to generate a driving signal based on current position information of an actuator;

[0161] The generation unit 1102 is configured to generate a hydraulic signal for a hydraulic valve based on the driving signal;

[0162] The second control unit 1103 is configured to control the hydraulic valve to control the motion state of the actuator based on the hydraulic signal, so as to adjust the position information of the actuator from the current position information to target position information, wherein the position information of the actuator is used to control the joint of the mechanical exoskeleton to move.

[0163] Optionally, the generation unit 1102 includes a generation module configured to drive a hydraulic pump to generate a hydraulic signal for a hydraulic valve based on the driving signal.

[0164] Optionally, the second control unit 1103 comprises a second control module configured to control a target speed and a target torque of the motion of the actuator based on the hydraulic signal, wherein the target speed is inversely proportional to the target torque.

[0165] Optionally, the second control module is further configured to determine a back electromotive force of the stator phase winding of the target motor during rotation of the target motor based on a trapezoidal wave function, wherein a waveform of the trapezoidal wave function is consistent with a waveform of the air gap magnetic field of the target motor; determine a stator phase winding voltage of the target motor based on the back electromotive force; and control the target motor to generate the driving signal based on the stator phase winding voltage.

[0166] Optionally, the second control module is further configured to determine the back electromotive force of the stator phase winding of the target motor during rotation of the target motor based on the trapezoidal wave function, comprising: determining the back electromotive force based on the trapezoidal wave function, a flux of the target motor, and an angular velocity of a rotor of the target motor.

[0167] Optionally, the trapezoidal wave function is determined based on an electromagnetic torque of the target motor.

[0168] Optionally, the stator phase winding voltage of the target motor is determined based on the back electromotive force, comprising: determining the stator phase winding voltage based on a resistance of the stator phase winding of the target motor, a current of the stator phase winding, and the back electromotive force.

[0169] Optionally, the three-phase Hall signals of the target motor are determined based on a target variable of the trapezoidal wave function, wherein the target variable is determined by a target phase angle of the target motor, and the three-phase Hall signals are signals of three-phase Hall effect sensors of the target motor.

[0170] Optionally, when a first Hall signal of the three-phase Hall signals is determined to have a phase abnormality, a phase of a second Hall signal of the three-phase Hall signals that has a normal phase is delayed to obtain a third Hall signal; and the first Hall signal is reconstructed based on the third Hall signal.

[0171] Optionally, the phase of the second Hall signal of the three-phase Hall signals that has the normal phase is delayed to obtain the third Hall signal, comprising: delaying the phase of the second Hall signal by a target electrical angle to obtain the third Hall signal, wherein the target electrical angle is used to represent a difference angle between the three-phase Hall signals.

[0172] In the driving device of the mechanical exoskeleton in this embodiment, first, a driving signal is generated according to current position information of the actuator, and then a hydraulic signal is generated based on the driving signal, so as to control the motion state of the actuator, and further adjust the actuator from the current position to the target position, thereby solving the technical problem of low safety of the mechanical exoskeleton in use, and achieving the technical effect of improving the safety of the mechanical exoskeleton in use.

[0173] Embodiment 4

[0174] According to the embodiments of the present disclosure, a computer readable storage medium is further provided. The computer readable storage medium includes a stored program, wherein the program, when executed by a processor, controls a device where the computer readable storage medium is located to perform the control method of the rope according to the embodiments of the present disclosure.

[0175] Embodiment 5

[0176] According to the embodiments of the present disclosure, a processor is further provided, which is used to execute a program, wherein the program, when executed, performs the control method of the rope according to the embodiments of the present disclosure.

[0177] The above-mentioned serial numbers of the embodiments of the present disclosure are only for description, and do not represent the advantages or disadvantages of the embodiments.

[0178] In the above-mentioned embodiments of the present disclosure, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0179] In several embodiments provided in the present application, it should be understood that the disclosed technical contents can be implemented by other means. Among them, the above-mentioned device embodiments are only schematic, for example, the division of the units can be a logical function division, and actual implementation can have another division mode, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units or models shown or discussed can be indirect coupling or communication connection through some interfaces, units or models, which can be electrical or other forms.

[0180] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or they can be distributed to multiple units. Part or all of the units can be selected according to actual needs to achieve the purpose of the present embodiment scheme.

[0181] In addition, each functional unit in each embodiment of the present disclosure can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be realized in the form of hardware or in the form of software functional unit.

[0182] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present disclosure, essentially or in other words, the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present disclosure. The aforementioned storage medium includes various media that can store program codes, such as a U disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, etc.

[0183] The above only describes the preferred embodiments of the present disclosure, and it should be pointed out that, for those skilled in the art, without departing from the principles of the present disclosure, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present disclosure.

Claims

1. A driving method of a mechanical exoskeleton, characterized by, The method comprises: determining a trapezoidal wave function based on an electromagnetic torque of a target motor; determining a back electromotive force based on the trapezoidal wave function, a flux linkage of the target motor, and an angular velocity of a rotor of the target motor, wherein a waveform of the trapezoidal wave function is consistent with an air gap magnetic field waveform of the target motor; determining a stator phase winding voltage based on a stator phase winding resistance, a stator phase winding current, and the back electromotive force of the target motor; controlling the target motor to generate a driving signal based on current position information of an actuator, wherein the controlling the target motor to generate the driving signal comprises controlling the target motor to generate the driving signal based on the stator phase winding voltage; generating a hydraulic signal for a hydraulic valve based on the driving signal; controlling the hydraulic valve to control a motion state of the actuator based on the hydraulic signal, so as to adjust position information of the actuator from the current position information to target position information, wherein the position information of the actuator is used to control a joint of a mechanical exoskeleton to move.

2. The method of claim 1, wherein, The method further comprises: driving a hydraulic pump to generate the hydraulic signal for the hydraulic valve based on the driving signal.

3. The method of claim 1, wherein, The method further comprises: controlling a target speed and a target torque of the actuator based on the hydraulic signal, wherein the target speed and the target torque are in an inverse relationship.

4. The method of claim 1, wherein: determining a three-phase Hall signal of the target motor based on a target variable of the trapezoidal wave function, wherein the target variable is determined by a target phase angle of the target motor, and the three-phase Hall signal is a signal of a three-phase Hall effect sensor of the target motor.

5. The method of claim 4, wherein, The method further comprises: determining a first Hall signal having a phase abnormality in the three-phase Hall signal, delaying a phase of a second Hall signal having a normal phase in the three-phase Hall signal to obtain a third Hall signal, and reconstructing the first Hall signal based on the third Hall signal. The method further comprises:

6. The method of claim 5, wherein, delaying the phase of the second Hall signal by a target electrical angle to obtain the third Hall signal, wherein the target electrical angle is used to represent a difference angle between the three-phase Hall signals. The method comprises:

7. A drive device of a mechanical exoskeleton, characterized by comprising: a first control unit configured to control a target motor to generate a driving signal based on current position information of an actuator, wherein the controlling the target motor to generate the driving signal comprises controlling the target motor to generate the driving signal based on a stator phase winding voltage; a generation unit configured to generate a hydraulic signal for a hydraulic valve based on the driving signal; a second control unit configured to control the hydraulic valve to control a motion state of the actuator based on the hydraulic signal, so as to adjust position information of the actuator from the current position information to target position information, wherein the position information of the actuator is used to control a joint of a mechanical exoskeleton to move. ​ The drive device of the mechanical exoskeleton is also configured to determine a trapezoidal wave function based on an electromagnetic torque of a target motor; determine a back electromotive force based on the trapezoidal wave function, a flux linkage of the target motor, and an angular velocity of a rotor of the target motor, wherein a waveform of the trapezoidal wave function is consistent with a waveform of an air gap magnetic field of the target motor; and determine a stator phase winding voltage based on a stator phase winding resistance, a stator phase winding current, and the back electromotive force of the target motor.

8. A computer-readable storage medium, characterized in that, The computer readable storage medium comprises a stored program, wherein the program, when executed by a processor, controls a device in which the computer readable storage medium is located to perform the method of any one of claims 1-6.

9. A processor, comprising: The processor is configured to execute a program, wherein the program, when executed, performs the method of any one of claims 1-6.

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