RU2335673C1 - Device stabilising lidar in horizon plane - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: device incorporates the casing with its position stabilised in space at external mechanical effects. It is arranged on the base to effect minor angular oscillations relative to the said base. The casing is made up of the upper and lower rings interconnected by struts. The upper ring is attached via the elastoviscous shock-absorbers arranged along the casing edges. The shock-absorbers consist of parallel flexible elements arranged in pairs and linear-type liquid dampers filled with viscous liquid. The brackets are attached to the car body floor.

EFFECT: simpler design and higher accuracy of lidar aiming in operating conditions in tracing objects.

1 dwg

Description

The invention relates to vibration technology and is intended for stabilization in the horizon plane of mobile lidars located on vehicles (for example, cars), which are affected by vibrating mechanical effects of a working car engine, which serves as a power generator of systems (navigation, television, gas analysis, functionally connected with lidar, weather systems, information),

Mobile lidars, rigidly mounted on the chassis (base, floor) of the transport device, as shown by experimental studies at the Institute of Atmospheric Optics SB RAS, experience mechanical vibrations of tens of hertz, leading to a change in the position of the light spot of the laser radiation on the probed object. Moreover, with an increase in the idle speed of the car engine, there is a tendency to increase the amplitude in individual frequency ranges.

There is a practice of installing devices on elastic shock absorbers, which either perform the functions of vibration absorbers of external disturbances, or, conversely, are dampers of the natural vibrations of the device (unit). The center of mass of the structure is located above the attachment points of the equipment and the efficiency of vibration absorption is determined only by the technical parameters of the elastic shock absorber.

By their principle of operation, such shock absorbers reduce the amplitude of oscillations, but do not eliminate it, moreover, a decrease in object vibrations in a certain frequency range.

Known passive type damper for reducing the amplitude of mechanical vibrations of the side rolling of the ship - Frome absorber (Mechanical vibrations and their role in technology. Publishing house "Science", the main edition of physical and mathematical literature. M., 1965, p. 156), selected as prototype, which contains communicating vessels filled with water, located on the sides of the ship. The principle of its operation is based on the inclination of the ship, a moment is created that is opposite to the roll moment, due to the displacement of the liquid, which is located in the tanks located on the sides of the ship. The disadvantage of this device is to reduce the amplitude of the oscillations, and not their elimination, in addition, this device can only work at very low frequencies, not more than tenths of a hertz units.

The objective of the invention is to provide a simple device for stabilizing the lidar in the horizontal plane and increasing the accuracy of the direction of the line of sight of the lidar in space in the operating mode when sensing objects.

The problem is solved due to the fact that in the proposed device stabilization of the lidar in the horizon plane containing the body, the position of which is stabilized in space under external vibrational mechanical influences and which is installed on the base with the ability to make small angular vibrations relative to this base

According to the invention, its housing consists of upper and lower rings interconnected by jibs, the upper ring being fixed through elastic-viscous shock absorbers located along the perimeter of the housing, consisting of parallel and pairwise arranged elastic elements and linear type liquid dampers filled with a viscous liquid, while the brackets, in turn, are fixed to the floor of the car.

The proposed device allows for stabilization of the object in the horizon plane due to the installation of the elastic elements of the beskardan suspension, providing the possibility of small angular movement of the frame along two orthogonal axes. When the case with the lidar is deflected, a moment arises opposite to the moment caused by external influences. In contrast to the prototype, the gimbal is replaced by orthogonally located four elastic elements and dampers, on which a lidar with a body is installed. These elastic elements with dampers enable small angular displacement similar to angular rotations relative to the axes of the frames of the gimbal.

The proposed device stabilization of the lidar in the horizon plane allows you to:

1. Hold the stabilization object strictly along the vertical of the place due to the pendulum of the frame.

2. Eliminate fluctuations in the line of sight of the lidar in the frequency range that occurs when the engine of the car is idling.

To explain the design of the proposed device, the figure shows its diagram.

In this diagram, the fastening of the nodes of an elastic-viscous suspension at the base, as well as the design of the elastic-viscous elements and the design of the optical system, are not conventionally shown in this diagram. The above does not interfere with understanding the essence of the principle of operation of the proposed device stabilization of the object in the horizon.

The composition of lidar 1 includes two telescopes: an emitter and a receiver. The optical elements of the telescopes are mounted on a common housing 2, representing a frame structure. The body 2 includes (upper 3 and lower 4) rings interconnected by jibs 5.

Lidar 1 is mounted on the upper ring 3 of the housing 2. The upper ring is fixed through elastic-viscous shock absorbers located along the perimeter of the housing, consisting of parallel-mounted pairwise mounted elastic elements 6 and liquid dampers of linear type 7, to the brackets 8. The brackets 8, in turn, are fixed to the base 9 cars 10.

An elastic element 6 and a damper 7 are attached to the upper ring 3. The elastic element 6 can be made in the form of a cylindrical compression screw spring or a multi-core compression screw spring, which has a flatter characteristic with small dimensions, or it can be an automobile spring.

The other end of the elastic element 6 is attached to the bracket 8.

In the process of transportation, to prevent damage to the elements of the moving part due to a collision with the case, there are two transport arresters 11 (conditionally shown in the figure) that rigidly fix the moving part of the mechanical system in space (lower ring 4 with brackets 8)

Damper 7 represents a typical design of a damping device of a linear type and consists of a cylindrical body mounted on the upper ring 3; the piston 13 mounted on the bracket 8. The piston 13 can be linearly moved in the damper housing 12, while the piston 13 is connected to the bracket 8 through a decoupling device that allows the piston 13 to make small angular movements in the damper housing 12. The internal cavity of the damper body is filled with a very viscous (e.g. polysiloxane) fluid.

Thus, lidar 1 is installed through elastic-viscous shock absorbers (spring 6, damper 7) on brackets 8, which, in turn, are attached to the car 10. The pendulum movable system has a center of mass (cm) below the plane of the elastic-viscous shock absorbers .

The proposed device operates as follows.

In the operating mode of the lidar 1, it is affected by vibrational mechanical loads from the working engine 9 of the car 10, which serves as a power generator of the systems (navigation, gas analysis, information, television, meteorological systems) functionally connected to the lidar 1.

Due to the pendulum of the mechanical system (lidar 1 - housing 2) at any time, the vertical position of this mechanical system is ensured along the vertical, and the suspension of the frame of elastic elements 6 and dampers 7 allows damping of vibrations from external mechanical influences, for example, from engine operation car 9 idling in the operating mode of lidar 1

In this device, the dynamics of the mechanical system (lidar-frame) is described by a system of differential equations:

,

,

where J _α , J _β are the moments of inertia of the frame relative to the suspension axis in orthogonal directions;

μ _α , μ _β - damping coefficients;

c _α , c _β are the stiffness coefficients of the elastic element;

P is the weight of the structure;

P is the frequency of external influences;

l is the distance from the axis to the center of mass of the moving part;

Q is the amplitude of the external periodic effect.

The maximum amplitude of the frame with external influence Q is determined by the expression

,

,

where k is the natural frequency of the frame, p is the frequency of external influences.

From the expression (1) it can be seen that the greater the difference between the natural frequency of the device and the external frequencies of the mechanical effect and the larger the damping coefficient μ, the smaller the oscillation amplitudes of the stabilizing device A.

Thus, the proposed device allows to solve the problem of eliminating the influence of external vibrational mechanical influences on the position of the line of sight of the lidar when probing objects, since in the operating mode of the lidar external vibrational mechanical influences will be damped in the elastic elements operating as a frequency filter due to the significant difference in their own low the frequency of a suspended mechanical pendulum, the role of which is played by a housing with a lidar fixed to it, and also quenched in parallel mounted elm their dampers, achieved the task of eliminating the influence of external vibration of mechanical impact on the lidar line of sight at sounding object. It should be borne in mind that in such a mechanical system, in the operating mode of the lidar, we have a case of small oscillations, when the natural frequency of the pendulum does not depend on the oscillation amplitude of the latter, which further increases the efficiency of the proposed passive stabilization system. The proposed device allows you to:

1) Due to the filtering properties of the elastic element (springs, springs), exclude external mechanical vibrational influences on the lidar of the working vehicle engine in the idle frequency range.

2) Additionally, due to the parallel inclusion in the design of the suspension unit of the damping device, additional absorption of external mechanical influences is made.

3) The presence of the pendulum ensures a constant position of the lidar in the horizontal plane in the vertical direction of the place, as well as stabilization of the mechanical system in the horizontal plane under unauthorized mechanical influences (for example, walking around the cabin, shifting the lidar equipment, etc.), causing the floor of the transport facilities.

Claims (1)

A lidar stabilization device in the horizon plane, comprising a housing whose position is stabilized in space under external vibrational mechanical influences and which is installed on the base with the ability to make small angular vibrations relative to this base, characterized in that its housing consists of upper and lower rings connected between by jibs, and the upper ring is fixed through elastic-viscous shock absorbers located along the perimeter of the body, consisting of parallel and pairwise arranged linear elastic elements and liquid dampers of linear type filled with viscous liquid, while the brackets, in turn, are fixed to the floor of the car.