Parallel branched legs for small unmanned vehicles carrying mobile equipment

Abstract

The application relates to a parallel type supporting chain leg of a small unmanned detection machine for carrying mobile equipment and belongs to the technical field of aerospace, which comprises a front landing gear and six main landing gears, the front landing gear is arranged at the front end of a machine body, the six main landing gears are symmetrically arranged at the two sides of the rear end of the machine body, and the front end of the machine body can realize forward inclination, backward inclination, upward movement and downward movement by controlling the extension and retraction of front buffer cylinders in the front landing gear and main buffer cylinders in the six main landing gears. The unmanned detection machine can realize forward inclination, backward inclination, upward movement and downward movement according to actual working conditions during work by adopting the multi-cylinder parallel type supporting chain leg, the anti-torsion structure and the locking mechanism are arranged on the main landing gears, the arrangement of the anti-torsion structure and the locking mechanism not only improves the impact resistance and the bearing capacity of the unmanned detection machine, but also prevents the supporting chain leg from moving or deforming during operation or work, improves the stability and safety of the unmanned detection machine, and has the advantages of compact structure, easy control and high motion control precision.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aerospace technology, and particularly relates to a small unmanned detection machine parallel type support chain leg for carrying mobile equipment. BACKGROUND

[0002] In recent years, small unmanned aerial vehicles are widely used in various fields due to their small size and strong maneuverability. Unmanned aerial vehicles can not only perform patrol work in the air, but also can perform work tasks in some dangerous environments. For example, they can carry detection vehicles and transport them to designated work sites for environmental exploration work, which requires unmanned aerial vehicles to have excellent carrying capacity, transportation capacity on complex ground and take-off and landing functions to smoothly complete the loading and unloading work of the detection vehicle and then complete the exploration task.

[0003] However, most of the existing unmanned aerial vehicle wheel leg mechanisms only play a supporting and buffering role and adopt a motor driving system, have limited carrying capacity and do not have a lifting function, resulting in that most unmanned aerial vehicles can only perform air patrol work and cannot smoothly travel on complex terrain and stop on complex terrain to perform ground exploration tasks. The unmanned aerial vehicle wheel leg mechanism is a multi-cylinder parallel mechanism, which needs multi-cylinder cooperative movement to realize the pitching of the unmanned aerial vehicle body and to ensure that the body forms a certain slope with the ground to facilitate the loading and unloading of various detection equipment. Therefore, the unmanned aerial vehicle support chain leg needs to have high precision controllability and high strength carrying capacity, and it is necessary to propose a small unmanned detection machine parallel type support chain leg for carrying mobile equipment to solve the above technical problems. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides a small unmanned detection machine parallel type support chain leg for carrying mobile equipment, which adopts a multi-cylinder parallel type support chain leg. When working, the unmanned aerial vehicle can realize forward tilting, backward tilting, upward movement and downward movement according to the actual working conditions, and an anti-torsion structure and a locking mechanism are arranged on the main landing gear. The arrangement of the anti-torsion structure and the locking mechanism not only improves the impact resistance and carrying capacity of the unmanned aerial vehicle, but also prevents the support chain leg from moving or deforming during operation or work, thereby improving the stability and safety of the unmanned aerial vehicle.

[0005] The technical scheme adopted by the present application is a kind of small unmanned detection machine for carrying mobile equipment parallel type branch chain leg, it includes front landing gear and six main landing gear, the front landing gear is located at the front end of fuselage, and the front landing gear includes front connecting block, front push rod, first force sensor, front buffer cylinder and front piston rod, the upper end of the front push rod is connected with the first rotating pair of the fuselage through the front connecting block, and the lower end of the front push rod is provided with front wheel, the front buffer cylinder is arranged at the rear side of the front push rod, the upper end of the front buffer cylinder is provided with the first force sensor, and the upper end of the first force sensor is connected with the second rotating pair of the fuselage through the front connecting block, the front piston rod slides in the front buffer cylinder, and the lower end of the front piston rod is connected with the third rotating pair of the front push rod;The six main landing gears are symmetrically arranged on both sides of the rear end of the fuselage, and each main landing gear includes second force sensor, transition plate, main buffer cylinder, rocker, main piston rod, rocker arm, main wheel, main connecting block and locking mechanism, the main landing gear is connected with the fuselage through the main connecting block, and the second force sensor is arranged below the main connecting block, the second force sensor is arranged below the transition plate, and the upper end of the main buffer cylinder is connected with the transition plate, the main piston rod slides in the main buffer cylinder, the main piston rod slides in the main buffer cylinder, and the lower end of the main piston rod is connected with the fourth rotating pair at the middle of the rocker arm, the rocker and rocker arm are arranged on the front side of the main buffer cylinder, the upper end of the rocker is connected with the fifth rotating pair of the side of the main buffer cylinder, the lower end of the rocker is connected with the sixth rotating pair of the upper end of the rocker arm, and the lower end of the rocker arm is provided with main wheel, the main buffer cylinder, rocker and rocker arm jointly constitute a quadrilateral mechanism, and the locking mechanism is arranged on the first side of the main buffer cylinder, by controlling the extension and contraction of the front buffer cylinder in the front landing gear and the main buffer cylinder in the six main landing gears, the front and rear inclination, ascending and descending movement of the fuselage can be realized.

[0006] Further, the locking mechanism includes first connecting rod, second connecting rod, third connecting rod and fourth connecting rod, the upper end of the first connecting rod is connected with the seventh rotating pair of the main connecting block, and the middle of the first connecting rod is connected with the upper end of the second connecting rod through the eighth rotating pair, the lower end of the second connecting rod is connected with the ninth rotating pair of the first side of the main buffer cylinder, the upper end of the third connecting rod is connected with the tenth rotating pair of the first side of the main buffer cylinder, the lower end of the third connecting rod is connected with the lower end of the first connecting rod and the upper end of the fourth connecting rod through the eleventh rotating pair, and the lower end of the fourth connecting rod is connected with the twelfth rotating pair of the first side of the main buffer cylinder.

[0007] Preferably, the first rotating pair center axis is parallel to the fourth rotating pair center axis, and the fourth rotating pair center axis is perpendicular to the seventh rotating pair axis.

[0008] Further, the front buffer cylinder is further provided with a first servo valve and a first displacement sensor, the first servo valve is located at the first side of the front buffer cylinder, the first displacement sensor is located at the second side of the front buffer cylinder, and the extension end of the first displacement sensor is connected with the lower end of the front piston rod in the front buffer cylinder through a clamping plate.

[0009] Further, the six main landing gears are each provided with a second servo valve and a second displacement sensor, the second servo valve is located at the second side of the main buffer cylinder, the second displacement sensor is located at the third side of the main buffer cylinder, and the extension end of the second displacement sensor is connected with the lower end of the main piston rod in the main buffer cylinder through a clamping plate.

[0010] Preferably, the bottom of the fuselage is further provided with a signal amplifier for converting sensor signals.

[0011] The characteristics and advantages of the present application are:

[0012] 1. The parallel chain leg of the small unmanned detection machine for carrying mobile equipment provided by the present application adopts a multi-cylinder parallel chain leg, the main landing gear and the front landing gear are sequentially extended and retracted according to the action sequence during work, the front tilt, rear tilt, ascending and descending movements of the unmanned aerial vehicle fuselage can be realized, the unmanned aerial vehicle can form a certain slope with the ground through fuselage pitching according to the actual working condition, the carrying capacity and the transportation capacity of the unmanned aerial vehicle in complex terrain can be improved, and the detection device is convenient to move and carry, so that the detection efficiency is improved.

[0013] 2. The parallel chain leg of the small unmanned detection machine for carrying mobile equipment provided by the present application is provided with a torsion-resistant structure mainly composed of a rocker and a rocker arm at the front side of the main landing gear, and is provided with a locking mechanism on one side of the main landing gear, the setting of the torsion-resistant structure and the locking mechanism not only improves the impact resistance of the whole main landing gear, but also prevents the main landing gear from moving or deforming during operation or work, thereby improving the stability and safety of the main landing gear.

[0014] 3. The parallel chain leg of the small unmanned detection machine for carrying mobile equipment provided by the present application integrates the servo valve, the force sensor, the displacement sensor and other components, greatly reduces the volume and mass of the buffer cylinder, makes the overall structure of the chain leg more compact, thereby significantly reduces the demand for installation space, and the buffer cylinder does not need external pipeline during work, which can greatly improve the working performance of the buffer cylinder.

[0015] 4. The parallel chain leg of the small unmanned detection machine for carrying mobile equipment provided by the present application adopts a servo control system motion, which can realize high-precision motion control to ensure smooth landing on complex and rugged terrain and reliably perform detection tasks. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is the schematic diagram of the parallel type supporting chain leg of the small unmanned detection machine for carrying mobile equipment according to the present application;

[0017] Figure 2 is the left view of the front landing gear according to the present application;

[0018] Figure 3 is the right view of the front landing gear according to the present application;

[0019] Figure 4 is the right view of the main landing gear according to the present application;

[0020] Figure 5 is the left view of the main landing gear according to the present application;

[0021] Figure 6 is the front view of the main landing gear according to the present application.

[0022] Main reference signs:

[0023] main landing gear 1; fuselage 2; front landing gear 3; second force sensor 4; transition plate 5; main buffer cylinder 6; second servo valve 7; rocker 8; main piston rod 9; second pin shaft 10; rocker arm 11; second fish-eye bearing 12; main wheel 13; second displacement sensor 14; main connecting block 15; second clamp 16; first connecting rod 17; second connecting rod 18; third connecting rod 19; fourth connecting rod 20; front connecting block 21; front push rod 22; first force sensor 23; front buffer cylinder 24; first servo valve 25; first displacement sensor 26; front piston rod 27; first fish-eye bearing 28, first clamp 29, first pin shaft 30; front wheel 31. DETAILED DESCRIPTION

[0024] To make the technical content, structural features, achieved purposes and effects of the present application clear, the following will be described in detail in combination with the drawings of the specification.

[0025] The parallel type supporting chain leg of the small unmanned detection machine for carrying mobile equipment according to the present application, especially for small unmanned detection machines, as shown in Figure 1 , comprises a front landing gear 3 and six main landing gears 1, and through controlling the extension and contraction of the front buffer cylinder 24 in the front landing gear 3 and the main buffer cylinder 6 in the six main landing gears 1, the front and rear tilting and the up and down movement of the fuselage can be realized.

[0026] As shown in Figure 2 and Figure 3As shown in the figure, the front landing gear 3 is arranged at the front end of the fuselage 2, and the front landing gear 3 comprises a front connecting block 21, a front push rod 22, a first force sensor 23, a front buffer cylinder 24 and a front piston rod 27, the upper end of the front push rod 22 is connected with the first rotary pair of the fuselage 2 through the front connecting block 21, and the lower end of the front push rod 22 is provided with a front wheel 31, the front buffer cylinder 24 is arranged at the rear side of the front push rod 22, the upper end of the front buffer cylinder 24 is provided with the first force sensor 23, and the upper end of the first force sensor 23 is connected with the second rotary pair of the fuselage 2 through the front connecting block 21, the front piston rod 27 slides in the front buffer cylinder 24, and the lower end of the front piston rod 27 is connected with the third rotary pair of the front push rod 22 through the first fish-eye bearing 28, the first pin shaft 30 and the first clamp 29, and the lowering and lifting of the front landing gear 3 are realized by the extension and retraction of the front piston rod 27.

[0027] Specifically, the front buffer cylinder 24 is further provided with a first servo valve 25 and a first displacement sensor 26, the first servo valve 25 is located at the first side of the front buffer cylinder 24, and the first displacement sensor 26 is located at the second side of the front buffer cylinder 24, and the extension end of the first displacement sensor 26 is connected with the lower end of the front piston rod 27 in the front buffer cylinder 24 through a clamping plate, so as to obtain the accurate position of the front piston rod 27 in the front buffer cylinder 24, thereby realizing the position control of the front buffer cylinder 24 and ensuring the smooth completion of the transportation action.

[0028] As shown in the figure, Figures 4-6 The six main landing gears 1 are symmetrically arranged at the two sides of the rear end of the fuselage 2, and each main landing gear 1 comprises a second force sensor 4, a transition plate 5, a main buffer cylinder 6, a rocker 8, a main piston rod 9, a rocker arm 11, a main wheel 13, a main connecting block 15 and a locking mechanism, the main landing gear 1 is connected with the fuselage 2 through the main connecting block 15, the second force sensor 4 is arranged below the main connecting block 15, the transition plate 5 is arranged below the second force sensor 4, the upper end of the main buffer cylinder 6 is connected with the transition plate 5, the transition plate 5 is used to realize the force transmission between the second force sensor 4 and the main buffer cylinder 6, the main piston rod 9 slides in the main buffer cylinder 6, and the lower end of the main piston rod 9 is connected with the fourth rotary pair of the middle part of the rocker arm 11, the rocker 8 and the rocker arm 11 are arranged at the front side of the main buffer cylinder 6, the upper end of the rocker 8 is connected with the fifth rotary pair of the side of the main buffer cylinder 6, the lower end of the rocker 8 is connected with the upper end of the rocker arm 11 through the second fish-eye bearing 12, the pin shaft 10 and the second clamp 16, and the lower end of the rocker arm 11 is provided with the main wheel 13, the main buffer cylinder 6, the rocker 8 and the rocker arm 11 jointly constitute a quadrilateral mechanism, which can avoid the main buffer cylinder 6 from being subjected to the radial force, better complete the action of tilting the fuselage and the like, and be beneficial to the transportation of the mobile equipment, and the locking mechanism is arranged at the first side of the main buffer cylinder 6, and is used to prevent the main landing gear from moving or deforming during the operation or work process, thereby improving the stability and safety of the main landing gear.

[0029] As shown in the figure, Figure 6As shown, the locking mechanism comprises a first connecting rod 17, a second connecting rod 18, a third connecting rod 19 and a fourth connecting rod 20, the upper end of the first connecting rod 17 is connected with the seventh rotary pair of the main connecting block 15, and the middle of the first connecting rod 17 is connected with the upper end of the second connecting rod 18 through the eighth rotary pair, the lower end of the second connecting rod 18 is connected with the first side of the main buffer cylinder 6 through the ninth rotary pair, the upper end of the third connecting rod 19 is connected with the first side of the main buffer cylinder 6 through the tenth rotary pair, the lower end of the third connecting rod 19 is connected with the lower end of the first connecting rod 17 and the upper end of the fourth connecting rod 20 through the eleventh rotary pair, and the lower end of the fourth connecting rod 20 is connected with the first side of the main buffer cylinder 6 through the twelfth rotary pair, the first rotary pair center axis is parallel to the fourth rotary pair center axis, and the fourth rotary pair center axis is perpendicular to the seventh rotary pair axis.

[0030] The second servo valve 7 is located on the second side of the main buffer cylinder 6, and the second displacement sensor 14 is located on the third side of the main buffer cylinder 6, and the extension end of the second displacement sensor 14 is connected with the lower end of the main piston rod 9 in the main buffer cylinder 6 through a clamping plate, so as to obtain the accurate position of the main piston rod 9 in the main buffer cylinder 6, thereby realizing the position control of the main buffer cylinder 6 and ensuring the smooth completion of the transportation action.

[0031] The bottom of the fuselage 2 is also provided with a signal amplifier for converting sensor signals. The first force sensor 23, the second force sensor 4, the first displacement sensor 26 and the second displacement sensor 14 are connected with the signal amplifier respectively, the signals are converted into electric signals through the amplifier, the signal processing and conversion are carried out by the industrial computer to output the voltage signals, the voltage signals are transmitted to the servo valve amplifier, and finally the opening sizes of the first servo valve 25 and the second servo valve 7 are controlled to realize the extension and retraction of the buffer cylinder, that is, the rising and falling of the landing gear, and whether the final position is reached is judged according to the signals of the first displacement sensor 26 and the second displacement sensor 14.

[0032] A parallel branch leg of a small unmanned detection machine for carrying mobile equipment according to the present application, as shown, comprises a front landing gear 3 and six main landing gears 1. Figures 1-6 During use, the front tilting, descending, rear tilting and ascending movements can be realized.

[0033] Forward movement: the front piston rod 27 of the front buffer cylinder 24 in the front landing gear 3 extends, pushing the front push rod 22 to drive the front wheel 31 to extend forward, at this time the front landing gear 3 is lowered, facilitating the detection equipment placed on the unmanned aerial vehicle to leave the unmanned aerial vehicle to perform the detection task. The main buffer cylinder 6 in the main landing gear 1 does not actively exert force but follows according to the positional relationship, the first force sensor 23 and the first displacement sensor 26 are connected with the amplifier respectively, the signals are converted into electrical signals through the amplifier, the signal processing and conversion are performed by the industrial computer to output the voltage signal, which is transmitted to the servo valve amplifier, and finally controls the opening size of the first servo valve 25 to realize the extension and retraction of the front piston rod 27 in the front buffer cylinder 24, i.e. the rising and lowering of the landing gear, whether the last position is reached is judged according to the signal of the first displacement sensor 26.

[0034] Lowering movement: the main piston rod 9 of the main buffer cylinder 6 in the main landing gear 1 retracts, the main buffer cylinder 6 in the main landing gear 1 is lowered, and the platform of the fuselage 2 is lowered as a whole to avoid damage caused by excessive force when the front landing gear 3 is retracted. The second force sensor 4 and the second displacement sensor 14 are connected with the amplifier respectively, the signals are converted into electrical signals through the amplifier, the signal processing and conversion are performed by the industrial computer to output the voltage signal, which is transmitted to the servo valve amplifier, and finally controls the opening size of the second servo valve 7 to realize the extension and retraction of the main buffer cylinder 6, i.e. the rising and lowering of the landing gear, whether the last position is reached is judged according to the signal of the second displacement sensor 14.

[0035] Rearward movement: the front piston rod 27 of the front buffer cylinder 24 in the front landing gear 3 retracts, and the front landing gear 3 is retracted. This action can also be used as the starting action for the transport equipment to enter from the rear side of the unmanned aerial vehicle. The first force sensor 23 and the first displacement sensor 26 are connected with the amplifier respectively, the signals are converted into electrical signals through the amplifier, the signal processing and conversion are performed by the industrial computer to output the voltage signal, which is transmitted to the servo valve amplifier, and finally controls the opening size of the first servo valve 25 to realize the extension and retraction of the front piston rod 27 in the front buffer cylinder 24, i.e. the rising and lowering of the landing gear, whether the last position is reached is judged according to the signal of the first displacement sensor 26.

[0036] Rising movement: the main piston rod 9 of the main buffer cylinder 6 in the main landing gear 1 extends, the main landing gear 1 is raised, and the platform of the fuselage 2 remains stable, and the unmanned aerial vehicle returns to the take-off preparation state. The second force sensor 4 and the second displacement sensor 14 are connected with the amplifier respectively, the signals are converted into electrical signals through the amplifier, the signal processing and conversion are performed by the industrial computer to output the voltage signal, which is transmitted to the servo valve amplifier, and finally controls the opening size of the second servo valve 7 to realize the extension and retraction of the main buffer cylinder 6, i.e. the rising and lowering of the landing gear, whether the last position is reached is judged according to the signal of the second displacement sensor 14.

[0037] The application adopts a multi-cylinder parallel type branched chain leg, and the main landing gear and the front landing gear are sequentially extended and retracted according to the action sequence during work, so that the forward tilting, backward tilting, ascending and descending movements of the unmanned aerial vehicle body can be realized; the unmanned aerial vehicle can be tilted to a certain slope with the ground according to the actual working condition, which not only improves the carrying capacity of the unmanned aerial vehicle and the transportation capacity under complex terrain, but also facilitates the movement of the carried detection device to improve the detection efficiency; meanwhile, a torsion-resistant structure mainly composed of a rocker and a rocker arm is arranged on the front side of the main landing gear, and a locking mechanism is arranged on one side of the main landing gear, so that the impact resistance of the whole main landing gear is improved, and the movement or deformation of the main landing gear during operation or work is prevented, so that the stability and safety of the main landing gear are improved; furthermore, the servo valve, force sensor, displacement sensor and other components are integrated together, so that the volume and mass of the buffer cylinder are greatly reduced, the overall structure of the branched chain leg is more compact, the demand for installation space is significantly reduced, the buffer cylinder does not need external pipelines during work, and the working performance of the buffer cylinder can be greatly improved; in addition, the servo control system is used for movement, so that high-precision movement control can be realized to ensure smooth landing on complex and rugged terrain and reliably perform the detection task.

[0038] The above-described embodiments are only used to describe the preferred embodiments of the present application, and various modifications and improvements to the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application defined by the claims.

Claims

1. A parallel branched leg for a small unmanned scout vehicle hosting mobile equipment, characterized by, It includes a front landing gear and six main landing gears, The front landing gear is arranged at the front end of the fuselage, and the front landing gear includes a front connecting block, a front push rod, a first force sensor, a front buffer cylinder and a front piston rod, the upper end of the front push rod is connected with the first rotating pair of the fuselage through the front connecting block, and the lower end of the front push rod is provided with a front wheel, the front buffer cylinder is arranged at the rear side of the front push rod, the upper end of the front buffer cylinder is provided with the first force sensor, and the upper end of the first force sensor is connected with the second rotating pair of the fuselage through the front connecting block, the front piston rod slides in the front buffer cylinder, and the lower end of the front piston rod is connected with the third rotating pair of the front push rod; The six main landing gears are symmetrically arranged at the two sides of the rear end of the fuselage, and each main landing gear includes a second force sensor, a transition plate, a main buffer cylinder, a rocker, a main piston rod, a rocker arm, a main wheel, a main connecting block and a locking mechanism, the main landing gear is connected with the fuselage through the main connecting block, the second force sensor is arranged below the main connecting block, the transition plate is arranged below the second force sensor, the upper end of the main buffer cylinder is connected with the transition plate, the main piston rod slides in the main buffer cylinder, and the lower end of the main piston rod is connected with the fourth rotating pair at the middle of the rocker arm, the rocker and the rocker arm are arranged at the front side of the main buffer cylinder, the upper end of the rocker is connected with the fifth rotating pair of the side surface of the main buffer cylinder, the lower end of the rocker is connected with the sixth rotating pair of the upper end of the rocker arm, and the lower end of the rocker arm is provided with a main wheel, the main buffer cylinder, the rocker and the rocker arm jointly constitute a quadrilateral mechanism, and the locking mechanism is arranged at the first side surface of the main buffer cylinder, by controlling the extension and contraction of the front buffer cylinder in the front landing gear and the main buffer cylinder in the six main landing gears, the forward and backward tilting and the upward and downward movement of the fuselage can be realized.

2. The parallel branched leg for a small unmanned vehicle carrying mobile equipment of claim 1, wherein, The locking mechanism includes a first connecting rod, a second connecting rod, a third connecting rod and a fourth connecting rod, the upper end of the first connecting rod is connected with the seventh rotating pair of the main connecting block, the middle of the first connecting rod is connected with the upper end of the second connecting rod through the eighth rotating pair, the lower end of the second connecting rod is connected with the ninth rotating pair of the first side surface of the main buffer cylinder, the upper end of the third connecting rod is connected with the tenth rotating pair of the first side surface of the main buffer cylinder, the lower end of the third connecting rod is connected with the lower end of the first connecting rod and the upper end of the fourth connecting rod through the eleventh rotating pair, and the lower end of the fourth connecting rod is connected with the twelfth rotating pair of the first side surface of the main buffer cylinder.

3. The parallel branched leg for a small unmanned vehicle carrying mobile equipment of claim 2, wherein, The central axis of the first rotating pair is parallel to the central axis of the fourth rotating pair, and the central axis of the fourth rotating pair is perpendicular to the axis of the seventh rotating pair.

4. The parallel branched leg for a small unmanned vehicle carrying mobile equipment of claim 1, wherein, The front buffer cylinder is further provided with a first servo valve and a first displacement sensor, the first servo valve is located at the first side surface of the front buffer cylinder, the first displacement sensor is located at the second side surface of the front buffer cylinder, and the extension end of the first displacement sensor is connected with the lower end of the front piston rod in the front buffer cylinder through a clamping plate.

5. The parallel branched leg for a small unmanned vehicle carrying mobile equipment of claim 4, wherein, The second servo valve is located on the second side of the main buffer cylinder, and the second displacement sensor is located on the third side of the main buffer cylinder, and the extension end of the second displacement sensor is connected with the lower end of the main piston rod in the main buffer cylinder through a clamping plate.

6. The parallel branched leg for a small unmanned vehicle carrying mobile equipment of claim 5, wherein, The bottom of the fuselage is also provided with a signal amplifier for converting sensor signals.

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