A manned lunar vehicle moving system and fault coping method capable of coping with multiple faults

Abstract

A manned lunar vehicle moving system and fault handling method capable of coping with multiple faults, (1) when the steering is damaged, the wheels normally travel; when the steering fails but can be reversed, the faulty wheel is turned back to normal and locked, and the whole vehicle uses the non-faulty wheel to steer; when the steering fails and cannot be reversed, if the steering angle is not at the limit angle when the faulty wheel is locked, the non-faulty wheel is used to steer, and if the steering angle is at the limit angle when the faulty wheel is locked, the steering is realized in a differential or torque coordination distribution mode. (2) When the drive assembly is damaged and the wheel surface is not damaged, the faulty wheel drive is unlocked to a follow-up state; when the steering is not damaged, the four-wheel steering is used and the steering angle of the faulty wheel is adjusted to match the friction braking force of each wheel and the moon surface to realize braking, and step (1) is used when the steering is damaged; (3) when the wheel surface is damaged, if the steering is not damaged or fails but can be reversed, the faulty wheel is turned back to normal and locked, and a spare wheel is inserted; if the steering fails and cannot be reversed, the faulty wheel is removed and a spare wheel is inserted to travel.

Description

TECHNICAL FIELD

[0001] The present application relates to a manned lunar rover moving system and a fault handling method capable of coping with multiple faults. The moving ability of the manned lunar rover under fault conditions is ensured by isolating the drive of the driving wheel, locking the steering, or replacing the driving wheel with a spare wheel. BACKGROUND

[0002] As an important transportation tool for astronauts to perform tasks on the moon in the future, the moving ability and return ability of the manned lunar rover under fault conditions are particularly important. The unknown environment on the moon has a greater impact on the driving ability of the driving wheels of the manned lunar rover, and situations such as wheel drive damage, wheel steering damage, or wheel surface damage may occur. In order to ensure the safety of astronauts, when the moving system of the manned lunar rover fails, sufficient fault handling measures need to be taken to ensure that it still has driving ability to return safely.

[0003] Currently, the manned lunar rover that has successfully landed on the moon multiple times is the Apollo lunar rover of the United States, which has four driving wheels. When the wheel rotation fails, the drive can be unlocked to turn it into a passive wheel, and the remaining wheels can be driven to maintain driving. This method can provide some fault handling capability, but when the wheel surface fails or the wheel completely loses its driving ability (such as being stuck), the entire vehicle will be unable to drive, and astronauts will still face a threat to their safety.

[0004] Patent: A large foldable manned lunar rover that can be separated and reconstructed, CN202210930140.3, proposed by Beijing Spacecraft General Design Department, provides a configuration scheme in which a large 4-wheel vehicle is separated into two small 3-wheel vehicles. When the driving wheels fail, the two vehicles are separated, and the small 3-wheel vehicle that is not damaged is used to return safely, ensuring the safety of astronauts. The passive wheels of this system are folded on the bottom plate of the vehicle and need to be released and supported on the lunar surface when separation is required. It has several obvious shortcomings: 1. The driving stability of a 3-wheel vehicle is poor, and when two people drive, the smaller passive wheels bear a large weight, which can easily sink into soft lunar soil, causing the required driving traction to increase rapidly, and in severe cases, the vehicle may not be able to continue driving; 2. It is mainly used for damage to wheels on the same end, such as single front wheel or double front wheel damage. When the front and rear wheels are damaged, the rear part of the vehicle will not function properly after separation, but when the front and rear wheels are damaged, the passive wheels are in the middle of the vehicle, so the passive wheels cannot replace the driving wheels when the two vehicles are not separated; 3. The vehicle increases the unlocking and separation mechanism for separation function, and many devices need to be duplicated, which has a large weight penalty, high complexity, and low reliability. In summary, this patent provides a method to improve safety, but there are still defects, and further improvement is necessary.

[0005] In summary, the current research results in the mobile system design of manned lunar rover still have room for improvement in safety. Considering the launch weight and volume constraints, the main improvement direction is to use simple mechanisms to achieve fault isolation or add fewer components. SUMMARY

[0006] The technical problem solved by the present application is to provide a manned lunar rover mobile system and fault handling method that can cope with multiple faults. When the drive steering assembly of the active wheel fails, the drive is unlocked and the steering is locked by the joystick. In the event of extreme damage to the active wheel, a passive wheel is inserted to maintain driving capability. The two methods together constitute a manned lunar rover suspension system with high overall safety, small added weight and volume.

[0007] The technical solution of the present application is a manned lunar rover fault handling method that can cope with multiple faults. The manned lunar rover has four active wheels with independent drive and independent steering. The fault handling method ensures that the vehicle still has the ability to return when 1-2 active wheels fail. The method includes the following steps according to the fault form:

[0008] Fault form one: steering failure, wheels normal driving, steering failure but reverse driving, lock the fault wheel after steering back to normal, the vehicle uses 3 or 2 non-fault wheels to steer; steering failure and no reverse driving, if the steering angle is not at the limit angle when the fault wheel is locked, use non-fault wheels to steer, if the steering angle is at the limit angle when the fault wheel is locked, use differential or torque distribution to steer;

[0009] Fault form two: drive failure, but the wheel surface is not damaged, unlock the fault wheel to follow the state; steering is not damaged, use 4-wheel steering and adjust the steering angle of the fault wheel to match the frictional braking force of each wheel on the moon to achieve braking, steering is damaged, use fault form one to handle;

[0010] Fault form three: wheel surface damage, if the steering is not failed or failed but can be reversed, lock the fault wheel back to normal and insert a spare wheel to replace the active wheel; if the steering is failed and cannot be reversed, remove the fault wheel and insert a spare wheel to drive.

[0011] Preferably, when the drive fails, the steering is not damaged, and the specific handling steps are as follows:

[0012] Real-time calculation of the required braking torque of each wheel, the braking torque divided by the wheel radius is the braking force, and the steering angle of the fault wheel is asin(braking force / (wheel lateral friction coefficient * wheel normal pressure));

[0013] When only one wheel fails, the wheel can be steered to either side, and when two wheels fail, the steering directions of the two fault wheels must be opposite to cancel the lateral component.

[0014] Preferably, if only 1 wheel steering fails, the remaining 3 wheels are used to realize steering by controlling the axes of the 3 wheels to intersect at the rotation center; if 2 wheels steering fail, the remaining 2 wheels are used to realize steering by controlling the axes of the 2 wheels to intersect at the rotation center.

[0015] Preferably, the replacement of the main drive wheel with a damaged surface by a standby wheel according to actual conditions comprises:

[0016] When the steering is not failed or the steering fails but can be reversed, the failed wheel is installed with the standby wheel after being adjusted, the ground contact point of the standby wheel is lower than that of the failed wheel, the failed wheel is lifted off the lunar surface, and the standby wheel replaces the failed wheel;

[0017] When the failed wheel steering fails and cannot be reversed, the failed wheel is removed and installed with the standby wheel, and the standby wheel replaces the failed wheel;

[0018] In the above two cases, the contact point of the standby wheel with the ground is lower than that of the other non-failed main drive wheel with the ground, and the height difference is adapted by the up-and-down movement of the moving suspension to realize full-wheel adhesion.

[0019] A mobile system of a manned lunar rover capable of coping with multiple failures, which realizes a failure coping method of a manned lunar rover capable of coping with multiple failures, comprises four groups of suspension assemblies and standby wheels, each group of suspension assemblies comprising a suspension mounting bottom plate, a suspension, a drive assembly, a steering assembly, a main drive wheel and a control lever.

[0020] One end of the suspension is mounted on the bottom plate of the manned lunar rover through the suspension mounting plate, and the other end of the suspension is connected to the steering assembly, the output shaft of the steering assembly is connected to the drive assembly, the drive assembly provides driving power, and the steering assembly provides steering power.

[0021] The standby wheel is installed at the corresponding interface of the steering assembly and fixed with the outer shell of the steering assembly when the main drive wheel surface is damaged; when the steering is not failed or failed but can be reversed, the failed wheel is adjusted and the standby wheel is directly installed without disassembling the failed wheel; the standby wheel does not contact the drive assembly of the main drive wheel and therefore has no active rotation ability, and the standby wheel rocker arm is fixed with the upper shell of the steering assembly and therefore has no steering ability. The standby wheel can only be passively rotated, and the forward direction of the wheel is the front-to-back direction of the vehicle body; after the standby wheel is installed, the failed wheel cannot be driven or steered; when the steering fails and cannot be reversed, the main drive wheel needs to be removed before the standby wheel is installed on the outer shell of the steering assembly, at which time the standby wheel is also in a passive rotation state.

[0022] Preferably, the drive assembly comprises a drive motor assembly, a harmonic reducer, an output shaft, a fixed groove, a sliding bearing, a drive pull ring and an elastic pressing plate.

[0023] The output shaft of the driving assembly is located in the center of the driving wheel spoke plate, one end of the driving assembly is connected to the output shaft of the steering assembly through the flange of the housing of the driving motor assembly, and the other end is provided with a fixed groove, a sliding bearing is arranged between the fixed groove and the driving wheel spoke plate, the fixed groove is an annular structure, a groove is arranged on the inner side of the structure for inserting and connecting with the petal structure on the output shaft of the driving assembly to realize torque transmission, the outer side of the annular structure is provided with two side protrusions and an outer convex groove which is outwardly inclined, the rectangular part of the driving pull ring is sequentially inserted into the gap between the two side protrusions and the outer convex groove through the driving wheel spoke plate, and is axially limited by the two spring plates on the outer side, the driving pull ring serves as a power transmission pin between the fixed groove and the driving wheel spoke plate when the driving pull ring is not pulled out; when the driving pull ring is pulled out, the elastic force of the elastic plate is broken, and then the driving pull ring is pulled out from the gap on the side of the fixed groove, so that the driving power cannot be transmitted to the driving wheel, and thus the driving wheel is unlocked to be in a follow-up state; when the driving wheel needs to be locked, the steering locking assembly is used to fix the rotation angle of the driving wheel.

[0024] The steering assembly comprises a steering motor assembly, a steering harmonic reducer, and a steering output shaft; the driving motor assembly drives the output shaft to rotate through the harmonic reducer, and then transmits the torque to the driving wheel spoke plate through the fixed groove and the driving pull ring, and drives the wheel to rotate; the steering motor assembly drives the steering output shaft to rotate through the steering harmonic reducer, and the steering output shaft is connected to the driving motor assembly, so that the driving assembly rotates around the steering output shaft, and then drives the wheel to steer.

[0025] Preferably, the steering locking assembly comprises a steering pull ring, a pin column, a pin cylinder, a compression spring, a pin, and an intermediate housing.

[0026] The housing of the steering assembly is divided into an upper housing, an intermediate housing, and a lower housing, and the three parts are fixedly connected; the upper housing is used to install the steering motor assembly, connect the upper suspension arm, and install a spare wheel; the intermediate housing is used to install the steering locking assembly; and the lower housing is used to install a steering position rotary variable and connect the lower suspension arm.

[0027] The intermediate housing is provided with a pin hole; the pin cylinder is installed on the intermediate housing and used to install the pin; the compression spring is installed between the pin and the bottom of the pin cylinder; the side wall of the pin is provided with an inner hole; in the unlocked state, the pin column connected to the steering pull ring is inserted into the inner hole of the pin, and the pre-tightening force of the compression spring prevents the pin column from being easily pulled out; in the locked state, the steering pull ring is pulled out to pull out the pin column, the pin is extended under the pushing force of the compression spring and enters the pin hole of the steering assembly output shaft after the steering assembly is returned to the normal position, and the locking is completed.

[0028] Preferably, the spare wheel comprises a passive wheel rocker arm, a wheel shaft assembly, a wheel, a plug, a claw, a rotating shaft, and a torsional spring.

[0029] The wheel is rotatably connected with one end of the rocker arm through an axle assembly, and a plug is installed at the other end of the rocker arm downwardly, two clamps are outwardly extended and installed inside the plug, a torsion spring is installed between the two clamps, the plug is used for cooperating with a socket on the upper shell of the wheel steering assembly, and after being inserted in place, the two clamps are extended and clamped into corresponding grooves on the upper shell of the wheel steering assembly under the pushing force of the torsion spring to realize locking.

[0030] After the spare wheel is installed, the active wheel which is not removed cannot rotate and steer, the spare wheel is lower than the active wheel in contact with the ground, the active wheel is lifted up by the spare wheel, and the active wheel is replaced by the spare wheel to travel, but the spare wheel has no steering capability.

[0031] Preferably, the operating rod comprises a hollow rod and a hook installed at the end of the hollow rod, the hook is used for hooking the driving pull ring and the steering pull ring to realize driving unlocking and steering locking.

[0032] Preferably, a support head is installed at the end of the operating rod which is not installed with the hook, the support head is used for supporting the vehicle body after the support head is inserted into the lunar soil, and the vehicle body is supported by the operating rod for removing the active wheel.

[0033] The present application has the following beneficial effects compared with the prior art:

[0034] The scheme of the present application for driving unlocking of the active wheel, steering locking and insertion of the spare wheel comprehensively guarantees the safe return of the manned lunar rover moving system under the fault working condition. In the extreme case of damage of the wheel surface, only simple driving unlocking and steering locking are needed to guarantee the driving capability, and the weight and volume of the added components are small. In the extreme case of damage of the wheel surface, the spare wheel is inserted to continue driving, and only two passive wheel components need to be carried on the vehicle body. The passive wheel rocker arm is simple in design and operation, and is automatically locked after being inserted. The weight of the passive wheel rocker arm is relatively light. The scheme of the present application is simple to realize, has small weight and volume cost, and is comprehensive and effective in fault response. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 Brake configuration for the failure wheel follow-up;

[0036] Figure 2 Response measure for the failure of two wheels of the steering assembly;

[0037] Figure 3 Response to the steering assembly lock failure;

[0038] Figure 4 Suspension wheel assembly with multiple failure response capability;

[0039] Figure 5 Sectional view of the active wheel driving failure isolation mechanism;

[0040] Figure 6 Side view of the active wheel driving failure isolation mechanism;

[0041] Figure 7 Active wheel steering fault isolation mechanism cross-sectional view;

[0042] Figure 8 Joystick;

[0043] Figure 9 Spare wheel installation process schematic diagram;

[0044] Figure 10 Spare wheel assembly diagram;

[0045] Figure 11 Spare wheel rocker arm vertical insertion mechanism. DETAILED DESCRIPTION

[0046] The application will be further described below in conjunction with examples.

[0047] The manned lunar rover is composed of a bottom plate and four groups of suspensions, each group of suspension has one active wheel, and the four wheels are independently driven and independently steered. The moving system of the manned lunar rover has four active wheels 5, and the main fault mode is that one or two active wheels 5 fail. The fault mode coping scheme proposed by the application is used to ensure that the whole vehicle still has the ability to return when one or two active wheels 5 fail. The main active wheel faults are wheel drive assembly 3 damage, wheel steering assembly 4 damage, and active wheel 5 surface damage. The fault coping method of the application ensures that the whole vehicle still has the ability to return when one or two active wheels fail. This method is mainly aimed at the three main fault forms of the moving system: drive assembly failure, steering assembly failure, and wheel surface failure. The three fault forms can occur independently or in combination. The fault coping method steps include:

[0048] Fault form one: steering failure, normal wheel travel, steering failure but reverse driving, after the fault wheel is steered back to normal and locked, the whole vehicle uses three or two non-fault wheels to steer; steering failure and no reverse driving, if the steering angle is not at the limit angle when the fault wheel is locked, use non-fault wheels to steer, if the steering angle is at the limit angle when the fault wheel is locked, use differential or torque coordination distribution to steer;

[0049] Fault form two: drive failure, but the wheel surface is not damaged, unlock the fault wheel drive to follow the state; steering is not damaged, use four-wheel steering and adjust the steering angle of the fault wheel to match the friction braking force of each wheel and the moon surface to realize braking, steering is damaged, use fault form one coping method;

[0050] Fault form three: wheel surface damage, if the steering is not failed or ineffective but can be reversed, steer the fault wheel back to normal and lock, and insert a spare wheel to replace the active wheel; if the steering is ineffective and cannot be reversed, remove the fault wheel and insert a spare wheel to drive.

[0051] Table 1 fault coping method

[0052]

[0053] When driving in failure, the steering is not damaged, and the steering angle of the failure wheel is adjusted to match the friction braking force of each wheel and the moon surface to realize braking: when the vehicle needs to brake, the control system will calculate the required braking torque of each wheel in real time, and the braking torque divided by the wheel radius is the braking force, and the failure wheel steering angle =asin(braking force / (wheel lateral friction coefficient * wheel normal pressure)). When only one wheel fails, the steering direction of the wheel can be either side, and when two wheels fail, the steering directions of the two failure wheels are opposite to offset the lateral component, as shown in Figure 1 .

[0054] If only one wheel steering fails, the remaining three wheels are used to realize steering, and the axes of the three wheels are controlled to intersect at the rotation center; if two wheels steering fail, the remaining two wheels are used to realize steering, and the axes of the two wheels are controlled to intersect at the rotation center, as shown in Figure 2 .

[0055] The present application gives a kind of manned lunar vehicle moving system to realize the above-mentioned failure response, as shown in Figure 4 , including four groups of suspension assemblies, spare wheel 7, each group of suspension assembly includes suspension mounting bottom plate 1, suspension 2, drive assembly 3, steering assembly 4, driving wheel 5, and the whole vehicle is equipped with 1 joystick 6;

[0056] The suspension is installed on the bottom plate of the manned lunar vehicle through the suspension mounting plate 1 at one end, and the other end is connected to the steering assembly 4, the output shaft 4-7 of the steering assembly 4 is connected to the drive assembly 3, and the drive assembly 3 provides driving power, and the steering assembly 4 provides steering power;

[0057] The spare wheel 7 is installed to the corresponding interface of the steering assembly 4 when the driving wheel surface is damaged and is fixed with the upper shell 4-8 of the steering assembly; when the steering is not failed or failed but can be reversed, the failure wheel is returned to normal, and the spare wheel 7 is directly installed without disassembling the failure wheel. The spare wheel 7 does not contact with the drive assembly 3 of the driving wheel, so it has no active rotation ability, and the spare wheel rocker arm 7-1 is fixed with the upper shell 4-8 of the steering assembly 4, so it has no steering ability. The spare wheel 7 can only be passively rotated, and the wheel forward direction of the vehicle body is the front and rear direction. After installing the spare wheel 7, the failure wheel cannot be driven and cannot be steered. When the steering fails and cannot be reversed, the driving wheel 5 needs to be removed before the spare wheel 7 can be installed on the upper shell 4-8 of the steering assembly, at which time the spare wheel is also in a passive rotation state.

[0058] As shown in Figure 5As shown, the drive assembly includes drive motor assembly 3-7, harmonic reducer 3-6, output shaft 3-1, fixed slot 3-2, sliding bearing 3-3, drive pull ring 3-4, elastic pressure plate 3-5;

[0059] The drive assembly output shaft 3-1 is located at the center of the driving spoke plate 5-1, and one end of the drive assembly is connected to the output shaft 4-7 of the steering assembly through the flange of the drive motor assembly 3-7, and the other end is installed with the fixed slot 3-2, and the sliding bearing 3-3 is installed between the fixed slot 3-2 and the driving spoke plate 5-1, the fixed slot 3-2 is an annular structure, the inner side of the structure is provided with a groove for realizing the insertion connection with the petal structure on the drive assembly output shaft 3-1, realizing torque transmission, the outer side of the annular structure 3-2 is provided with two side protrusions and an outwardly convex groove, the rectangular part of the drive pull ring 3-4 passes through the driving spoke plate 5-1, the gap between the two side protrusions to the outer convex groove, and is axially limited by the two spring pressure plates 3-5 on the outer side, when the drive pull ring 3-4 is not pulled out, it serves as a power transmission pin between the fixed slot 3-2 and the driving spoke plate 5-1; When the drive pull ring 3-4 is pulled, it breaks through the elastic force of the elastic pressure plate 3-5, and then is pulled out from the gap on the side of the fixed slot 3-2, so that the driving power cannot be transmitted to the driving wheel, thus realizing the unlocking of the driving wheel to the follow-up state; When the driving wheel needs to be locked, the steering locking assembly is used to fix the steering angle of the driving wheel;

[0060] As shown in Figure 6 , the drive motor assembly 3-7 drives the output shaft 3-1 to rotate through the harmonic reducer 3-6, and then transmits the torque to the driving spoke plate 5-1 through the fixed slot 3-2 and the drive pull ring 3-4, and then drives the wheel 5 to rotate; The steering motor assembly drives the steering output shaft to rotate through the steering harmonic reducer, and the steering output shaft is connected to the drive motor assembly 3-7, so that it will make the drive assembly 3 rotate around the steering output shaft 4-7, and then drive the wheel 5 to steer.

[0061] The steering assembly 4 includes a steering motor assembly, a steering harmonic reducer, and a steering output shaft. The steering motor assembly drives the steering output shaft to rotate through the steering harmonic reducer, and the steering output shaft is connected to the drive motor assembly, so that it will make the drive assembly rotate around the steering output shaft, and then drive the wheel to steer. The steering assembly and the drive assembly inside the present application are similar in structure, but the performance is different due to different models; The shell of the steering assembly is divided into an upper shell 4-8, an intermediate shell 4-6 and a lower shell, and the three parts are fixedly connected, the upper shell 4-8 is used to install the steering motor assembly, connect the upper suspension arm and install the spare wheel 7; The intermediate shell 4-6 is used to install the steering locking assembly, and the lower shell is used to install the steering position rotary variable and connect the lower suspension arm.

[0062] As shown in Figure 7As shown, the steering locking assembly includes a steering pull ring 4-1, a pin column 4-2, a pin barrel 4-3, a compression spring 4-4, a pin 4-5, and an intermediate housing 4-6; the intermediate housing 4-6 is provided with a pin hole; the pin barrel 4-3 is installed on the intermediate housing 4-6 and used for installing the pin 4-5; the compression spring 4-4 is installed between the pin 4-5 and the bottom of the pin barrel 4-3; the side wall of the pin 4-5 is provided with an inner hole; in a non-locking state, the pin column 4-2 connected with the steering pull ring 4-1 is inserted into the inner hole of the pin 4-5 from the side wall of the pin barrel 4-3; the pin column 4-2 is not easily pulled out by using the pre-tightening force of the compression spring 4-4; when locking, the steering pull ring 4-1 is pulled out and then the pin column 4-2 is pulled out; the pin 4-5 is extended under the thrust of the compression spring 4-4 and enters the pin hole of the steering assembly output shaft 4-7, and the locking is completed.

[0063] As shown in Figure 9 , 10 , 11, the spare wheel includes a passive wheel rocker arm 7-1, a wheel shaft assembly 7-2, a wheel 7-3, a plug 7-4, a claw 7-5, a rotating shaft 7-6, and a torsional spring 7-7; the wheel is rotatably connected with one end of the rocker arm through the wheel shaft assembly 7-2; the other end of the rocker arm is downwardly installed with the plug 7-4; two claws 7-5 are outwardly extended and installed inside the plug 7-4; the torsional spring 7-7 is installed between the two claws 7-5; the plug 7-4 is used for cooperating with the insertion hole on the upper housing 4-8 of the wheel steering assembly; after being inserted in place, the two claws 7-5 are extended and clamped into the corresponding grooves on the upper housing 4-8 of the wheel steering assembly under the thrust of the torsional spring 7-7, and the locking is realized.

[0064] As shown in Figure 8 , the operating rod 6 includes a hollow rod 6-2 and a hook 6-1 installed at the end of the hollow rod 6-2; the hook 6-1 is used for hooking the driving pull ring 3-4 and the steering pull ring 4-1, and realizing the driving unlocking and the steering locking.

[0065] The non-hook installed end of the operating rod 6 is installed with a supporting head 6-3, which is used for supporting the vehicle body after being inserted into the lunar soil, and is used for disassembling the driving wheel 5.

[0066] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application by using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, which does not deviate from the technical solutions of the present application, shall fall within the protection scope of the present application.

Claims

1. A multi-fault tolerant manned lunar rover mobility system, characterized by: The application relates to a four-wheel suspension lunar rover, which comprises four sets of suspension assemblies, spare wheels, a suspension mounting base plate, a suspension, a driving assembly, a steering assembly, a driving wheel and a control lever. One end of the suspension is mounted on the bottom plate of the lunar rover through the suspension mounting plate, and the other end of the suspension is connected to the steering assembly; the output shaft of the steering assembly is connected to the driving assembly; the driving assembly provides driving power; and the steering assembly provides steering power. When the driving wheel surface is damaged, the spare wheel is installed at the corresponding interface of the steering assembly and is fixed to the steering assembly shell; when the steering is not failed or is failed but can be reversed, the faulty wheel is returned to normal, and the spare wheel is directly installed without disassembling the faulty wheel. When the steering is failed and cannot be reversed, the driving wheel needs to be removed, and then the spare wheel is installed to the steering assembly shell; the spare wheel has no driving and steering capability and is in a passive rotating state. The driving assembly comprises a driving motor assembly, a harmonic reducer, an output shaft, a fixed groove, a sliding bearing, a driving pull ring and an elastic pressing plate. The output shaft of the driving assembly is located at the center of the driving wheel spoke plate; one end of the driving assembly is connected to the output shaft of the steering assembly through the flange of the driving motor assembly shell; and the other end is provided with the fixed groove; the sliding bearing is arranged between the fixed groove and the driving wheel spoke plate; the fixed groove is a ring structure; a groove is arranged on the inner side of the ring structure for realizing insertion connection with the petal structure on the output shaft of the driving assembly and realizing torque transmission; the outer side of the ring structure is provided with two side protrusions and an outwardly protruding groove; the rectangular part of the driving pull ring passes through the driving wheel spoke plate, the gap between the two side protrusions and the outwardly protruding groove in sequence, and is axially limited by the two spring pressing plates on the outer side; when the driving pull ring is not pulled out, the driving pull ring serves as a power transmission pin between the fixed groove and the driving wheel spoke plate; when the driving pull ring is pulled, the elastic force of the elastic pressing plate is broken, and then the driving pull ring is pulled out from the gap on the side of the fixed groove; the driving power cannot be transmitted to the driving wheel, so that the driving wheel is unlocked to be in a passive state; when the driving wheel needs to be locked, the steering locking assembly is used to fix the rotation angle of the driving wheel. The steering assembly comprises a steering motor assembly, a steering harmonic reducer and a steering output shaft. The driving motor assembly drives the output shaft to rotate through the harmonic reducer, and then transmits the torque to the driving wheel spoke plate through the fixed groove and the driving pull ring, so that the wheel is driven to rotate. The steering motor assembly drives the steering output shaft to rotate through the steering harmonic reducer; the steering output shaft is connected to the driving motor assembly, so that the driving assembly is rotated around the steering output shaft, and the wheel is steered.

2. The mobile system for a lunar lander of claim 1, wherein: The steering locking assembly comprises a steering pull ring, a pin column, a pin cylinder, a compression spring, a pin and an intermediate shell. The shell of the steering assembly is divided into an upper shell, an intermediate shell and a lower shell, and the three parts are fixedly connected; the upper shell is used for mounting the steering motor assembly, connecting the upper suspension arm and mounting the spare wheel; the intermediate shell is used for mounting the steering locking assembly; and the lower shell is used for mounting the steering position rotary variable and connecting the lower suspension arm. The intermediate shell is provided with a pin hole; a pin cylinder is installed on the intermediate shell for installing a pin; a compression spring is installed between the pin and the bottom of the pin cylinder, the side wall of the pin is provided with an inner hole, in a non-locking state, the pin column connected by the steering pull ring is inserted into the inner hole of the pin from the side wall of the pin cylinder, the pin column cannot be easily pulled out by using the pre-tightening force of the compression spring, in the locking state, the steering pull ring is pulled out and the pin column is pulled out, the pin is stretched out under the thrust of the compression spring and enters the pin hole of the output shaft of the steering assembly, and the locking is completed.

3. The mobile system for a lunar lander of claim 2, wherein: The spare wheel comprises a passive wheel rocker arm, a wheel shaft assembly, a wheel, a plug, a claw, a rotating shaft and a torsional spring. The wheel is rotatably connected to one end of the rocker arm through the wheel shaft assembly, the plug is installed at the other end of the rocker arm, two claws are outwardly extended and installed in the plug, the torsional spring is installed between the two claws, the plug is used for cooperating with the jack in the upper shell of the wheel steering assembly, after being inserted into the position, the two claws are extended and locked in the corresponding grooves in the upper shell of the wheel steering assembly under the thrust of the torsional spring.

4. The mobile system for a lunar lander of claim 1, wherein: The operating rod comprises a hollow rod and a hook installed at the end of the hollow rod, the hook is used for hooking the driving pull ring and the steering pull ring, and driving unlocking and steering locking are realized.

5. The mobile system of the lunar lander of claim 4, wherein: The non-hook end of the operating rod is provided with a supporting head, which is used for supporting the vehicle body after being inserted into the lunar soil, and is used for disassembling the driving wheel.

6. A method for coping with the failure of a mobile system of a manned lunar rover capable of coping with multiple failures according to claim 1, characterized in that: The manned lunar rover has four driving wheels which are independently driven and steered. The failure response method ensures that the whole vehicle still has the ability to return when one or two driving wheels fail, and the response steps include: Failure form one: steering failure, normal wheel driving, steering failure but reverse driving, after the steering of the failed wheel is returned to normal and locked, the whole vehicle is steered by three or two non-failed wheels; steering failure and no reverse driving, if the steering angle is not at the limit angle when the failed wheel is locked, steering is realized by using non-failed wheels, if the steering angle is at the limit angle when the failed wheel is locked, steering is realized by using differential or torque coordination distribution; Failure form two: driving failure, but the wheel surface is not damaged, the failed wheel is unlocked to be a follower; steering is not damaged, four-wheel steering is adopted and the steering angle of the failed wheel is adjusted to match the friction braking force of each wheel and the moon surface to realize braking, steering is damaged, and the failure form one is adopted for response; Failure form three: wheel surface damage, if the steering is not failed or ineffective but can be reversed, the steering of the failed wheel is returned to normal and locked, and the spare wheel is inserted to replace the driving wheel; if the steering is ineffective and cannot be reversed, the failed wheel is removed and the spare wheel is inserted to drive.

7. The method of claim 6, wherein: When the driving fails, the specific processing steps when the steering is not damaged are as follows: Real-time calculation of the required braking torque of each wheel, the braking torque divided by the wheel radius is the braking force, and the steering angle of the failed wheel is asin(braking force / (wheel lateral friction coefficient * wheel normal pressure)); When only one wheel fails, the wheel can be steered to either side, and when two wheels fail, the steering directions of the two failed wheels are opposite to offset the lateral component.

8. The method of claim 6, wherein: If only one wheel fails to steer, the remaining three wheels are used to realize steering, and the axes of the three wheels are controlled to intersect at the rotation center; if two wheels fail to steer, the remaining two wheels are used to realize steering, and the axes of the two wheels are controlled to intersect at the rotation center.

9. The method of claim 6, wherein: The third form of failure, the insertion of a spare wheel instead of the driving wheel includes: When the steering is not failed or the steering is failed but can be reversed, the spare wheel is installed after the failed wheel is aligned, the contact point of the spare wheel is lower than the contact point of the failed wheel, the failed wheel is lifted off the lunar surface, and the spare wheel replaces the failed wheel; When the failed wheel steering is failed and cannot be reversed, the failed wheel is removed, the spare wheel is installed, and the spare wheel replaces the failed wheel; In the above two cases, the contact point of the spare wheel with the lunar surface is lower than the contact point of other non-failed driving wheels with the lunar surface, and the height difference is adapted through the up-down movement of the moving suspension to realize full-wheel adhesion.

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