RU2780069C1 - Highly mobile research rover - Google Patents

Abstract

FIELD: space engineering.

SUBSTANCE: invention relates to space engineering and is intended to increase the mobility of research rovers. The planet rover is mounted on a statically balanced two-track two-wheeled chassis with dynamic stability control. The wheels of a uniaxial planetary rover are mounted on the chassis frame on a spring-loaded suspension in the form of carriages suspended on springs on vertical racks of the frame. The rover is equipped with large-area folding disk-shaped solar panels. A wind power plant in the form of a flat rotor with a vertical axis is installed on the body. The wheel rims are equipped with arcuate dampers-grousers made of alloy steel.

EFFECT: increase in the mobility and efficiency of space expeditions to planets with a solid surface is achieved.

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Description

The invention relates to space engineering and is intended for use in the creation of autonomous mobile robotic research stations-planetary rovers for the study of planets with a solid surface, mainly the Moon and Mars.

Autonomous mobile robotic research stations-planetary rovers for space expeditions are known, which are a body aggregated on an all-terrain chassis with built-in and mounted navigation and research equipment and solar cells.

The success of the mission of the research rover and the entire space expedition with a long flight and landing on the surface of the planet under study is determined by the mobility of the rover, which determines the length of the route traveled by the rover during the active operation of the route. The length and complexity of the routes of movement are planned based on the cross-country ability, controllability, maneuverability, observability of control, energy efficiency and survivability of the chassis, which determine the technical speed of movement of the planetary rover. The maximum speed of movement of modern planetary rovers is meters per second, and the technical speed is calculated in centimeters per second.

The following technical solutions are known, similar in technical essence:

1. A.L. Kemurdzhian, V.V. Gromov, I.F. Kazukalo, MM. Malenkov, V.K. Mishkinyuk, V.N. Petriga, IM. Rosenzeig. Planet rovers. Moscow. "Engineering". 1993.

2. Email resource: - https://cyberleninka.ru/article/n/analiz-podvizhnosti-marsohodov-dlya-razrabotki-sistem-peredvizheniya-i-algoritmov-upravleniya-planetohodami-novogo-pokoleniya.

3. Mastering the universe. Planet rovers. Past, present, future - Information copied from the site https://robotics.ua/shows/modernity/3003-the_development_of_the_universe_planetary_rovers_past_present_future; https://ru.qwe.wiki/wiki/Rocker-bogie.

4. Dobretsov R.Yu., Matrosov S.I., Borisov E.G., Komarov I.A., Telyatnikov D.E. MOBILE COMPLEX OF LOCAL MONITORING RCL-LAB.[ //https://www.elibrary.ru/item.asp?id=32854031]

5. V.N. Naumov, O.E. Kozlov, K.Yu. Mashkov, K.E. Byakov. Analysis of the designs of elastic wheels for promising Russian lunar rovers in terms of assessing the passability. Email resource: - http://izvuzmash.ru/articles/1455/1455.pdf.

6. Michaud, Saint-Fan; Gibbesch, A.; Ther, Thomas; Krebs, Ambroise; Lee, C.; Despont, B.; Schfer, B.; Slade, R. Development of the ExoMars chassis and locomotion subsystem. Email resource: - https://doi.org/10.3929/ethz-a-010034575.

7. Malenkov Mikhail Ivanovich, Volov Valery Anatolyevich. COMPARATIVE ANALYSIS OF UNDERCARRIAGE COMPONENTS OF SELF-PROPELLED CHASSIS OF PLANET ROVERS. Email resource: https://cyberleninka.ru/article/n/sravnitelnyy-analiz-komponentov-hodovoy-chasti-samohodnyh-shassi-planetohodov.

8. Ramón Gonzalez, Dimitrios Apostolopoulos. Improving rover mobility through traction control: simulating rovers on the Moon. Email resource: - https://www.researchgate.net/publication/331689572_Improving_rover_mobility_through_traction_control_simulating_rovers_on_the_Moon.

9. Ramon Gonzalez, Karl Iagnemma. Slippage estimation and compensation for planetary exploration rovers. State of the art and future challenges. Email resource:

10. Raymond Arvidson P. De Grosse Jr. John P. Grotzinger E. K. Stilly. Relating geologic units and mobility system kinematics contributing to Curiosity wheel damage at Gale Crater, Mars. Email resource:-

11. In-situ Exploration and Sample Return: Autonomous Planetary Mobility. [https://mars.nasa.gov/mer/mission/technology/autonomous-planetary-mobility/].

12. Scott Moreland, Krzysztof Skonieczny, David Wettergreen, Vivake Asnani, Colin Creager, Heather Oravec. Inching Locomotion for Planetary Rover Mobility. https://ri.cmu.edu/pub_files/2011/3/inching_ieeeAERO2011.pdf.

13. Michaud, Stéphane, Gibbesch, A. Thüer, Thomas, Krebs, Ambroise, Lee C., Despont B., Schäfer B., Slade R. Development of the ExoMars Chassis and Locomotion Subsystem.

[https://www.researchgate.net/publication/224999438_Development_of_the_ExoMars_Chassis_and_Locomotion_Subsystem].

14. V.N. Naumov, O.E. Kozlov, K.Yu. Mashkov, K.E. Byakov. Analysis of the designs of elastic wheels for promising Russian lunar rovers in terms of assessing the passability. // NEWS OF HIGHER EDUCATIONAL INSTITUTIONS. ENGINEERING №8 [689] 2017. S. - 54-66.

15. M.I. Malenkov, V.A. Volov, N.K. Guseva, E.A. Lazarev. ANALYSIS OF MOBILITY OF MARS ROVERS FOR THE DEVELOPMENT OF PROMOTION SYSTEMS AND ALGORITHMS FOR CONTROL OF PLANET ROVERS OF A NEW GENERATION // Izvestiya SFU. Technical sciences Izvestiya SFedU. Engineering Sciences. S. - 82-95.1.

16. Robert Bauer, Winnie Leung, Tim Barfoot. DEVELOPMENT OF A DYNAMIC SIMULATION TOOL FOR THE EXOMARS ROVER. // 8th ESA Workshop on Advanced Space Technologies for Robotics and Automation, ASTRA 2004, ESTEC, Noordwijk, The Netherlands, 2-4 November, 2004, pp. 251-258.

17. M.I. Malenkov, V.A. Volov. COMPARATIVE ANALYSIS OF UNDERCARRIAGE COMPONENTS OF SELF-PROPELLED CHASSIS OF PLANET ROVERS. // Izvestiya SFedU. Technical sciences Izvestiya SFedU. Engineering Sciences. S. - 169-185.

18. Becker M.G. Introduction to the theory of terrain-machine systems. Engineering. 1973 520s.

19. Wang Qionga, Yu Dengyunc, Jia Yangb. Research progress and future development on mission planning technologies of planetary rover. Email resource: - https://www.sciencedirect.com/science/article/pii/S1877705814038120.

19. Richard Volpe. Rover Functional Autonomy Development for the Mars Mobile Science Laborator. Email resource: - https://www-robotics.jpl.nasa.gov/publications/Richard_Volpe/aerospace03.pdf

20. NASA's Next Mars Rover to Test Tech Useful for Human Missions. Email resource:- https://www.nasa.gov/directorates/spacetech/NASAs_Next_Mars_Rover_to_Test_Tech_Useful_for_Human_Missions.

21. Extended Length Marsupial Rover Sensing Tether. LUNA INNOVATIONS INCORPORATED. Email resource: - https://www.sbir.gov/sbirsearch/detail/1426353.

In order to achieve the increase in the effectiveness of planetary research, which is necessary for modern astronautics, it is necessary to increase the maximum speed of planetary rovers to tens of meters per second and the technical speed to meters per second. Achieving such speeds of movement over complex terrain with practically unknown soil properties should be ensured with extremely stringent restrictions on the weight and size characteristics of the chassis and the power-to-weight ratio of the planetary rover. Added to these conditions are technical difficulties due to cosmic radiation, low gravity, lack of an atmosphere, high abrasiveness and cohesiveness of the lunar regolith, or winds and dust storms on Mars. Another set of problems is created by a significant difference between the night and day temperatures of the surface of the planetary rover and the soil.

Currently, the most common six-wheeled chassis with a 6 × 6 × 4 wheel scheme with rocker-bogie type balancer suspension. A series of NASA rovers Sojourner, Spirit, Opportunity, Curiosity, Persevirance, the Chinese lunar rover Yutu and the promising European planetary rover Rosalind Franklin are aggregated on such chassis. This wheel scheme with balancer suspension provides the highest cross-country ability in the class of machines with multi-wheel chassis. But the balancing suspension of the wheels can only partially compensate for the shortcomings of the multi-wheeled chassis.

Firstly, the advantages of a chassis with a balancing wheel suspension are manifested when all wheels are evenly loaded. This condition is met when driving over terrain with a high bearing capacity of soil with irregularities, the radius of curvature of the envelope of which exceeds the radius of curvature of the longitudinal patency. When driving on slopes, uniform loading of the wheels is possible only in suspensions with active adaptation - the ability to shift the center of mass of the rover to the wheels with reduced load. Chassis of modern rovers do not have this ability. As a result, as a result of the addition of the static redistribution of the vertical load and the action of the reactive moment on the wheel drives, the load on the wheels is distributed unevenly and significantly limits the longitudinal permeability of planetary rovers. In multi-wheel chassis with passive balancing suspensions, the reactive moment from the wheels redistributes the load to the rear wheels. As a result, when driving uphill on loose, weakly cohesive soil, these features are manifested in the slipping of overloaded rear wheels and burying them in loose soil, and in the slipping of underloaded front wheels with the same effect. Under the conditions on the surface of Mars, rocky areas are more suitable for cross-country ability. When a wheel of a Curiosity-type rover hits a stone with a height exceeding the swing amplitude of the rocker arm, individual wheels sag and the six-wheel chassis turns into a four-wheel chassis with a corresponding loss of traction and controllability.

Secondly, since the resistance force F _c to the movement of a wheel of radius R with a load P when hitting an obstacle with a height h changes as

in conditions of movement along the road with obstacles commensurate with the radius of the wheels, the energy efficiency of a multi-wheeled chassis remains low even with a balancing suspension on long rocker arms due to the fact that some of the wheels will inevitably move in the kinematic mismatch mode.

Thirdly, in planetary rovers on the Rocker-Bogie chassis, the body is rigidly connected to the swing axis of the suspension rocker arms by means of gearing in the differential mechanism that combines the body of the vehicle with the onboard half-axes of rocker arm swing with propellers, or an additional balancing lever connecting the body to the suspension rocker arms. The differential mechanism and an additional balancer provide the body with half the angles of deviation of the body in the longitudinal plane from the horizontal than the angles of deviation of the rocker arms. When moving along a complex terrain with fast deflections of the rocker arms, the reactive moments on the nodes of the differential mechanism and in the attachment points of the balancing arm become significant, which creates an additional restriction on the speed of the planetary rover moving over uneven surfaces.

Fourth, another significant drawback of a multi-wheeled landing gear with balanced wheel suspension is the inconsistency with the requirement for a compact design of the planetary rover. The chassis of the Spirit, Opportunity, Curiosity, and Perseverance rovers, due to the large dimensions of its rocker arms, had to be supplemented with four reduced hinges, allowing them to be folded and the front wheels deployed. The total mass of these devices, not involved in setting the planetary rover in motion, reaches 7% of its mass. This is without taking into account the gearmotors on the four steering wheels, which provide control of the angle of rotation of the front and rear wheels. When maneuvering, the front and rear wheels of planetary rovers go beyond the dimensions of the planetary rover, reducing its longitudinal dynamic permeability.

To prevent excavation of wheels buried in loose soils or dangerous concentrations of load on the chassis suspension units due to difficult terrain, it is necessary to perform a large amount of work on choosing the route for passing the next section of the track. This significantly reduces the technical speed of movement of planetary rovers. To increase the efficiency of the preliminary analysis of the conditions of movement, the latest version of the rover, Perseverance, was equipped with a flying drone capable of short-term flights for reconnaissance and providing the artificial intelligence of the rover control unit with information about the nature of the terrain on the route of movement. To resort to such measures is also forced by the danger of collision of wheels with sharp edges of boulder fragments during the movement of the planetary rover. Because of such collisions, not only the resistance to the movement of the planetary rover increases, but the wheels themselves are also damaged. Especially such effects are manifested when driving down the slope, when the dynamic moments on the rear wheels press the front wheels into the ground. To prolong the life of the damaged front wheels on the rover, Curiosity had to switch to reverse and load a special program into its motor-wheel control system, "which constantly analyzes how each of Curiosity's six wheels presses on the ground, and controls the movement of each of them in real time mode. Thanks to it, the rover can move at a speed at which the wheels will not slip and push each other into pebbles and other potentially dangerous objects, as well as slip or turn in place. In reality, these measures are palliative, do not lead to the complete exclusion of slippage or excavation of wheels into the ground.

Fifth, due to the fact that the terrain-machine system with a six-wheeled chassis has 30 redundant connections, during the movement and maneuvering of the machine, states of kinetic mismatch occur in the system, leading to a decrease in the controllability and observability of the control of the movement of the machine.

Known attempts to overcome these shortcomings of the Rocker-Bogie scheme by creating wheel-walking chassis of various kinematic schemes are futile, since the redundancy of these structures is even greater, and the mass of additional - ballast - units and mechanisms is tens of percent of the mass of the structure, which excludes their use for creating mobile autonomous research stations for space expeditions.

Thus, the chassis of modern autonomous robotic planetary rovers do not have sufficient cross-country ability, controllability, maneuverability, control observability, sufficient technical speed and chassis survivability to provide the mobility necessary to increase the efficiency of space expeditions.

The objective of the invention is to achieve a technical result in the form of increased mobility of research rovers.

The specified technical result is achieved by the fact that the research planetary rover is mounted on a statically balanced two-track two-wheeled chassis with dynamic stability control (hereinafter referred to as a single-axle chassis).

A single-axle chassis increases the mobility of various vehicles (RF patents No. 2090429, 2102272, 2405122, 2421202) due to a number of technical features.

Firstly, in a statically balanced single-axle chassis, the diameter of the wheels is a multiple of the diameter of the wheels of a multi-wheeled chassis. A multiple larger diameter of the wheel propeller automatically provides a multiple increase in the energy efficiency of overcoming a single obstacle due to the dependence indicated in (1). According to this dependence, with a twofold increase in the radius of the wheel from a value of about 1.1 of the height of the obstacle, the force of resistance to the movement of the wheel decreases by more than five times and continues to decrease with a further increase in the radius of the wheel, creating the effect of "smoothing" the path. Accordingly, the energy efficiency of a single-axle chassis when overcoming obstacles significantly exceeds the energy efficiency of a multi-wheel chassis.

Secondly, the speed-limiting vibration loads on the body are reduced due to a decrease in the number of collisions of propellers with obstacles and a decrease in vertical accelerations during a single collision with obstacles in accordance with the ratio of vertical accelerations for wheels of different radii, proportional to the ratio

where k is the ratio of the wheel radii, and ή is the ratio of the height of the obstacle to the radius of the smaller wheel.

In accordance with this ratio, with a two-fold increase in the radius of the wheel, the value of vertical acceleration decreases by 1.43 times and, accordingly, the vibration loads on the body of the planetary rover decrease by a factor of 1.

To dampen shocks transmitted to the body of the planetary rover from the frame of a single-axle landing gear, the wheels of a single-axle planetary rover are mounted on the chassis frame on a spring-loaded suspension. To do this, carriages are put on the vertical racks of the reverse U-shaped frame, to which wheels are attached, the carriages are connected to the frame racks by springs, and between them by a cable-block system that acts as a stabilizer of the rover's transverse stability. Also, the carriages can be freely installed on the vertical racks of the frame and interconnected by a cable-block system with a spring insert. The carriages can be kinematically decoupled from the frame posts by means of sliders or linear bearings.

Thirdly, a single-axle statically balanced chassis has a much smaller number of redundant links in the terrain-machine system. In particular, in the terrain-machine system with a rover on a single-axle chassis with an additional degree of freedom in the form of a controlled displacement of the body relative to the chassis, there are 7 redundant links. Accordingly, in comparison with a multi-wheeled planetary rover, a planetary rover on a single-axle chassis moves almost in the mode of complete kinematic compliance, and the controllability and observability of the control of such a planetary rover is significantly higher than that of a planetary rover of any other design.

Fourth, unlike multi-wheeled planetary rovers, a planetary rover on a single-axle chassis has no passability limitation due to longitudinal clearance. Also, there is practically no restriction of patency due to the stop of body elements protruding beyond the dimensions of the mover into an obstacle.

Fifth, a multiple reduction in the excavation immersion of propulsors into the ground due to the greater ground clearance of a wheel of a larger radius ensures overcoming areas that are insurmountable for Curiosity/Perseverance-type planetary rovers due to burrowing of loaded wheels into loose soil. Accordingly, route selection time and route length are reduced.

In general, taking into account the above factors, a planetary rover on a single-axle chassis with the weight and dimensions of the Curiosity/Perseverance rovers will be able to cover the Curiosity route with a multiple higher technical speed due to an increase in the coefficients of geometric, dynamic geometric and reference passability and an increase in the maximum speed of movement of for the effect of "smoothing the path", as well as increasing energy efficiency, maneuverability, controllability and observability of control due to movement in the kinematic compliance mode.

To increase the power-to-weight ratio of the planetary rover, solar cells are installed on a single-axle chassis - large-area photoelectric converters in the form of folding disk panels connected to each other by hinges, fixed on hinged brackets, installed in containers kinematically decoupled from the wheels, driven or not driven from individual engines, containers for solar cell panels in disks wheels. During the movement of planetary rovers, the panels are folded into containers in wheel disks. In the battery charging mode, the planetary rover is installed so that the deployed solar cell panels are directed towards the Sun, and the drives in the mounts of the hinged brackets or in the mounts of the containers, according to the signals from the sun position sensors, give the panels an optimal angle of inclination. In another variant, thermal and/or photoactive rods/pushers attached to the panels or to hinged brackets can be used as drives for adjusting the inclination of the panels, changing their geometric parameters when sunlight hits them and changing the angle of inclination of the panels.

To increase the survivability of rovers at night and in winter, a wind power plant in the form of a flat rotor with a vertical axis is installed on the body body, designed to recharge the batteries of the planetary rover in the absence of sunlight or the impossibility of opening solar panels in strong winds.

To reduce shock loads on the structure of the planetary rover and increase the adhesion of wheels to the ground, the wheel rims of the planetary rover are equipped with arched dampers-lugs made of alloy steel, which dampen shock loads on the wheels due to elastic deformation and increase the traction characteristics of the wheels when moving on weakly cohesive soils. Grouser dampers have the form of semi-ellipsoid arcuate strips, fixed with their ends at the edges of the wheel rim at an angle to the plane of the longitudinal section of the wheel and at an angle to each other. The width of the dampers, the angle of inclination to the plane of the wheel and the ellipticity of the damper-lug arc are determined in accordance with the gravitational conditions on the surface of the planet under study, taking into account the nature of the terrain and soil in the study area. Also, in accordance with the expected conditions of movement over the terrain, the profile of the longitudinal section of the steel strip of the damper-lug, necessary to ensure the effectiveness and longevity of dampers-lugs, the points of attachment of the ends of the damper-lugs to the rim, necessary to ensure the effectiveness and longevity of the dampers-lugs, are determined - in the area of the location of the near focal parameters, or in the area of the location the ends of the major axis of the ellipse, or in the region of the far focal parameters, and the nature of the attachment of the damper-lug to the rim - rigid or articulated.

General views of the layout design of the planetary rover on a single-axle chassis are shown in Fig. 1, 2, 3 and 4.

Figure 1 shows schematic representations of the front view of the rover with semi-deployed disk solar panels, side view and top view, as well as a cutout "A" of an exemplary view of a possible design of the attachment point of the lateral stability cable to the frame of the planetary rover and the attachment point of the support roller for the support rail body. The figures indicate: 1 - the body of the planetary rover; 2 - reverse U-shaped frame of the supporting structure of the planetary rover; 3 - soft suspension carriage for the wheels of the planetary rover; 4 - wheels of the planetary rover; 5 - support roller of the frame; 6 - brackets for fastening the support rollers of the frame; 7 - cable block of transverse stability of the planetary rover; 8 – lateral stability cable; 9 - soft suspension springs; 10 - block of video systems; 11 – wind turbine impeller; 12 - root panel of the solar battery; 13 - secondary panel of the solar battery; 14 - bracket; 15 – bracket hinge; 16 - butt hinge of the solar battery; 17 - interpanel hinge of the solar battery.

On FIG. 2 additionally approximate possible types of design of the wheel suspension to the frame and the wheel drive are indicated: 18 - a basket for fastening the hub to the body of the soft suspension carriage; 19 - mounting plate; 20 - screw for fastening the wheel gear to the wheel disk; 21 - the crown of the drive wheel of the gearbox; 22 - bearing housings for mounting the hub on the soft suspension carriage; 23 - flange for fastening the wheel drive motor reducer to the wheel reducer housing; 24 - wheel gear cover; 25 - e / motor of the motor reducer.

On FIG. 3 additional designations are not available.

On FIG. 4 additional designations are not available. Schematic representations are presented. I - front view of the planetary rover when moving on a flat flat horizontal surface; II - front view of the planetary rover when it hits a one-sided obstacle without a lateral stability cable. III - view of a planetary rover with a lateral stability cable when hitting a one-sided obstacle.

These differences in the design of the planetary rover provide a technical result in the form of increased mobility and can increase the efficiency of space expeditions to planets with a solid surface.

Claims (1)

A highly mobile research rover for space expeditions, which is a body mounted on an all-terrain chassis with built-in and attached navigation and research equipment and solar panels in the form of flat panels with photoelectric converters attached to them, characterized in that the research rover is mounted on a statically balanced two-track two-wheeled chassis with dynamic stability control (hereinafter referred to as a single-axle chassis) in the form of a controlled movement of the body relative to the wheels under the action of a drive that gives the body an acceleration of relative movement in accordance with the magnitude and direction of the resulting moment on the drive wheels of the planetary rover, and the drive wheels of the planetary rover are mounted on the chassis frame on a spring-loaded suspension, by means of carriages moving along the vertical racks of the frame and connected to them by springs, interconnected by a cable-block system of transverse stability of the plane rover, and the solar batteries of the rover are bundles of panels with photoelectric converters fastened with hinges, installed in containers located in the cavity of the wheel rims kinematically uncoupled from them with the possibility of opening and changing the inclination of the panel planes, and on the body of the planet rover there is a wind generator in the form of a flat rotor with a vertical axle, and on the rims of the wheels dampers-lugs are fixed in the form of semi-ellipsoid arcuate strips, fixed with their ends on the edges of the wheel rim at an angle to the plane of the longitudinal section of the wheel and at an angle to each other.

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