RU2747331C1 - Motion stabilization system for self-propelled transport and technological vehicles - Google Patents

Abstract

FIELD: motion stabilization systems.SUBSTANCE: invention relates to motion stabilization systems for self-propelled transport and technological vehicles. The stabilization system contains a hydraulic cylinder with a dynamic load absorption device, including elastic and damping elements. The output of the position sensor of the movable component is connected to the input of the control unit relatively to the case. The elastic element is made in the form of gas springs. On each of the gas springs, damping elements are installed in the form of controlled chokes connected to the output of the control unit. Each of the gas springs is connected by pipelines through controlled chokes to a hydraulic cylinder.EFFECT: eliminating the resonance of the mobile component and the case is achieved.1 cl, 9 dwg

Description

The invention relates to systems for stabilizing the movement of self-propelled transport and technological machines (TTM) for agricultural, road-building, military and other purposes with a component having mobility relative to the machine body, in the form of mounted or semi-mounted functional equipment, working bodies and other devices.

When driving on a road with irregularities, self-propelled TTMs perceive external disturbing forces that deflect the machine body relative to the supporting surface and cause vibrations in all its parts. The action of the selected processes is accompanied by an increase in dynamic loads not only on units and parts, but also on machine operators, creating uncomfortable or even unsafe working conditions for them, as well as complicating the machine control process. It is known that the action of dynamic loads is the reason for a decrease in the speed and productivity of self-propelled TTMs up to 40-50%. In this connection, the development of systems for stabilizing the movement of TTM is an urgent task for modern mechanical engineering.

Since self-propelled vehicles, as a rule, have an uneven distribution of weight along the axes of the wheels, wheels of different standard sizes and, accordingly, stiffness, when the TTM moves on a road with irregularities, first of all, longitudinal-angular oscillations of the body relative to the supporting surface occur. Based on the analysis of the design and layout of self-propelled vehicles, the authors found that it is possible to reduce the negative phenomena associated with longitudinal-angular vibrations of self-propelled TTMs, possibly by absorbing vibrational energy, if an elastic-dissipative connection between the body and the moving component is provided, or stabilizing forces are applied to the body. due to the forced rotation of the movable component relative to the body. As a result of the analysis of the prior art of the invention, the following analogs and prototype were identified.

Known stabilization system for self-propelled transport and technological machines based on the principle of active dynamic stabilization, involving the application to the machine body of stabilizing forces from the actuator when turning the rolling component relative to the body, described in RF Patent No. 2708404, publ. 06.12.2019, IPC F16F 13/02 "Method of stabilizing the movement of self-propelled transport and technological machines." Such a system has state sensors, a control unit and an actuator that rotates the movable part of the machine relative to its body. When such a TTM moves along irregularities, linear and angular oscillations of the body occur, to which the condition sensors react and transmit a signal to the control unit. The control unit processes the signal from the status sensors and transmits the control signal to the actuator, which ensures the rotation of the moving part in the desired direction and with the specified kinematic parameters. A hydraulic, electromechanical, pneumatic or other type of drive can be used as an actuator for turning the movable part of the machine.

The disadvantages of a dedicated system include:

- the formation of additional dynamic loads on the supporting system and parts of the interface of the actuator with the body and the movable component;

- deterioration of vibration loading of the operator's workplace as a result of actuation of the executive drive;

- significant energy costs for stabilization, due to the need to apply efforts to the moving part of the machine.

Closer in technical essence is the system of motion stabilization of mobile mobile cranes selected as a prototype (Patent FR 2543936 - A1 Publicationdate: 1984-11-28 Inventor (s): OL-IPHANT LARRY JAMES Applicant (s): HARNISCHFEGER CORP), implemented on the basis of a hydraulic cylinder of a special design as a device that perceives and absorbs dynamic loads between the body and the moving part. When such a TTM moves along irregularities, its body sways and makes the movable component vibrate, the mobility of which is provided by a hydraulic cylinder with a device for absorbing dynamic loads. In this case, due to vibrations of the movable component, the working fluid is pushed out into the piston cavity from the rods of the zone of the hydraulic cylinders and vice versa. In the process of overflow, the liquid receives resistances from the chokes of a given flow area and zones with compressed gas available in the system. The specified elasticity is determined by the volume and pressure of the compressed gas, and the level of damping is provided by the selection of the flow area of the channels along the path of the working fluid flow. Thus, if we consider the TTM as a system consisting of a body and a moving component, then the body is stabilized by smoothing and absorbing vibrational energy in a device for absorbing dynamic loads by converting it into heat.

Driving over a single unevenness

In the case of overcoming a single unevenness, the body receives perturbation and transfers it to the moving component through the suspension with elastic and damping devices that provide smoothing and absorption of vibrations. Since the TTM received a single disturbance, then on the oscillogram one can observe the transient process until the position of the body and the adapter is completely stabilized due to the dissipation of the vibration energy.

Long road travel

In the case of prolonged movement on a road with irregularities, the machine body and the movable component perform harmonic oscillations: the frame relative to the supporting surface, and the movable component relative to the frame. In this case, according to the condition of ensuring the effect of dynamic damping, the vibration frequency of the body should be less than the vibration frequency of the movable component.

After the start of movement, the body receives perturbation from the supporting surface, as a result of which it vibrates and induces perturbations on the moving component, which has mobility relative to the body. For some time, each of the parts vibrates independently of each other, however, due to the difference in vibration frequencies, a moment comes when the directions of movement of the parts coincide, and as a result, a resonance effect occurs, which manifests itself in a sharp increase in the amplitude of vibrations not only of the movable component as less massive element TMM, but also the body as a result of the transfer of disturbances to it from the moving component.

As a result of the emerging resonances, additional dynamic loads arise on the driver, the body and the moving component, which does not allow the use of this system in transport modes of movement.

Thus, this system has the following disadvantages:

- the complexity of the system design. The system assumes the presence of a non-standard hydraulic cylinder of a special design;

- limited efficiency. The system is effective in case of collision with single obstacles. In the case of prolonged movement of the TTM on an uneven road, the resonance of vibrations of the movable composite mass relative to the body with vibrations of the body relative to the support base is possible;

- the impossibility of regulating the elastic and damping characteristics of the system, which makes it possible to stabilize movements after colliding with a single unevenness only for a specific mounted rolling component. In the case of using a different rolling component, the efficiency of the system is reduced.

Based on the analysis of the conditions of movement, the design and layout of the TTM, the authors found that in the case of a prolonged movement of the TTM on an uneven road with a rolling component connected to the body using an elastic-damping connection, the resonant phenomenon can be eliminated by short-term detuning of the natural vibration frequencies of the rolling component relative to the body, for which it will be necessary to promptly change the dynamic characteristics of the vibrating system of the moving composite mass, for example, by changing the stiffness of the elastic-damping connection.

The objective of the invention is to reduce the dynamic loads acting on the machine, its parts and the operator during prolonged movement of self-propelled TTM on an uneven road with a component of the machine having mobility relative to its body, in the form of mounted or semi-mounted functional equipment, working bodies and other devices.

The technical result is the elimination of resonance of the rolling component and the housing when implementing dynamic vibration damping during prolonged movement on an uneven road by promptly changing the suspension stiffness of the rolling component and, accordingly, the natural vibration frequency of the rolling component relative to the housing.

The specified technical result is achieved due to the fact that the system for stabilizing the movement of self-propelled transport and technological machines contains a hydraulic cylinder with a device for absorbing dynamic loads, including elastic and damping elements, and the system additionally contains a control unit and a position sensor of the moving component relative to the body, the output of which is connected to the input of the control unit, and the elastic element is made in the form of two or more gas springs with damping elements installed on each of them in the form of controlled throttles connected to the output of the control unit, while each of the gas springs is connected by pipelines through controlled throttles to a hydraulic cylinder.

FIG. 1 shows a diagram and the main elements of a self-propelled TTM.

FIG. 2 shows an oscillogram of the angles of inclination of the body 1 and the movable component 2 in the case of prolonged movement on the road with irregularities of the TTM with rigid fastening of the movable component 2 with the frame 1, obtained as a result of experimental measurements.

FIG. 3 shows schematically presented oscillograms of the angles of inclination of the housing 1 and the movable component 2 in the case of prolonged movement on the road with irregularities of the TTM with rigid fastening of the movable component 2 with the housing 1.

FIG. 4 shows schematically presented oscillograms of the angles of inclination of the housing 1 and the movable component 2 in the case of a TTM hitting a single unevenness when the dynamic stabilization system is turned on with a constant level of elastic-damping properties.

FIG. 5 shows the oscillograms of the angles of inclination of the body 1 and the movable component 2 in the case of continuous movement of the TTM on the road with irregularities with the included dynamic stabilization system with a constant level of elastic-damping properties, obtained as a result of experimental measurements.

FIG. 6 shows schematically presented oscillograms of the angles of inclination of the housing 1 and the movable component 2 in the case of continuous movement of the TTM on the road with irregularities with the included dynamic stabilization system with a constant level of elastic-damping properties.

FIG. 7 shows schematically presented oscillograms of the angles of inclination of the housing 1 and the movable component 2 in the case of prolonged movement on the road with irregularities of the TTM with the developed stabilization system.

FIG. 8 shows the oscillogram of the caster angles of the combine body obtained by means of simulation modeling when driving on a dirt road at a speed of 15 km / h with a developed stabilization system, as well as with a stabilization system, which has a constant level of elastic-damping properties.

FIG. 9 shows the oscillogram of the caster angles of the combine body obtained by means of simulation modeling when driving on a dirt road at a speed of 15 km / h with a developed stabilization system, as well as with a stabilization system, which has a constant level of elastic-damping properties.

Description of positions and accepted designations in the figures:

1 - case;

2 - movable component;

3 - hydraulic cylinder;

4 - device for absorbing dynamic loads;

5 - controlled choke;

6 - gas spring;

7 - control unit;

8 - position sensor of the movable component 2 relative to the housing 1;

9 - pipeline;

10 - swing joint of the movable component 2 relative to the housing 1;

11, 12 - hinges connecting the hydraulic cylinder with the housing 1 and the movable component 2, respectively;

C _to - the position of the center of mass of the body 1;

ϕ _C - the angle of the longitudinal inclination of the body 1 relative to the horizon;

ϕ ₀ - the angle of inclination of the movable component 2 relative to the horizon;

ϕ _0-C is the angle of rotation of the movable component 2 relative to the housing 1.

Statics

The system for stabilizing the movement of self-propelled transport and technological machines contains a hydraulic cylinder 3 with a device for absorbing dynamic loads 4, including elastic and damping elements. The system additionally contains a position sensor of the movable component 8 relative to the housing 1, the output of which is connected to the input of the control unit 7, the elastic element is made in the form of two or more gas springs 6 with damping elements installed on each of them in the form of controlled throttles 5 connected to the output control unit 7, with each of the gas springs 6 connected by pipelines 9 through controlled throttles 5 to the hydraulic cylinder 3.

The system of stabilization of the movement of self-propelled TTM can be implemented on the example of TTM with a rigid connection of the axles of the wheels with the body 1 and a rather massive movable component 2, which, thanks to the hydraulic cylinder 3 and the hinges 10, 11, 12, has one rotational degree of freedom relative to the body 1. An obligatory element of the system is a device for absorbing dynamic loads 4 connected to the hydraulic cylinder 3, including controlled throttles 5 and gas springs 6, also connected to the control unit 7 and the position sensor of the movable component 8 relative to the housing 1 (Fig. 1).

The presented example of a machine can be considered as a two-mass dynamic system (Fig. 1), between the main elements of which an elastic-damping connection is organized, and the specified change in the vibration frequency of the rolling component 2 relative to the housing 1 can be provided by operatively adjusting the rigidity of the device for absorbing dynamic loads 4 for by closing one or more gas springs by means of controlled throttles 5 6.

Changes in the parameters of the elastic-damping device is ensured by changing the number of connected gas springs and the stiffness of each of them, as well as the size of the flow area determined by the degree of opening of the controlled throttles 5 on the path of the working fluid flow from the hydraulic cylinder 3 to the gas springs 6. For this, the system is operatively through controlled (e) throttle (s) 5 disconnects one or more gas springs 6 from the hydraulic cylinder 3 (Fig. 1). The efficiency of the system is determined not only by the amount of absorbed energy in the device for absorbing dynamic loads 4, but also by the dynamic parameters (the direction of the acting forces, reactions and moments) between the housing 1 and the movable component 2.

As elastic elements of the device for absorbing dynamic loads, gas springs 6 can be used, which are containers, the internal volume of which is divided by means of an elastic diaphragm into two cavities, one of which is filled with gas, and the other with a working fluid and communicates with the hydraulic cylinder 3 by means of pipelines 9 ...

The parameters of the gas springs 6 are determined by their stiffness. Rigidity should be understood as a property of gas springs 6, similar to the stiffness of a compression spring and is defined as the ratio of the applied force to the angle of rotation of the movable component 2 relative to the housing 1. The stiffness of the gas springs 6 of the device for absorbing dynamic loads 4 is determined by the gas pressure, as well as the area of action on the elastic diaphragm ...

The damping properties of the device for absorbing dynamic loads 4 are determined by the flow area of the channel and pipelines connecting the hydraulic cylinder 3 and the gas springs 6. The flow area can also be changed using controlled throttles 5.

Dynamics

We will consider the working process of the developed stabilization system using the example of a self-propelled TTM, which includes a body 1 and a movable component 2 in the form of attachments located in front, between which, due to the hydraulic cylinder 3, fixed on the hinges 11 and 12, and the hinge 10, one rotational degree of freedom is provided. When the TTM is moving with the stabilization system turned off, the body of the machine 1, due to the compliance of the tires, performs mainly longitudinal-angular oscillations relative to the point C _to . The oscillogram ϕ _C and ϕ ₀ (Fig. 2) shows the harmonic synchronous nature of the change in these parameters. The vibration amplitude is determined by the nature of the interaction of the wheel with the road, the parameters of the unevenness of the road, the vibration frequency is determined by the mass-inertial parameters of the TTM, the stiffness of the tires, and other parameters. Since the movable component 2 is rigidly connected to the housing 1, in FIG. 2 and FIG. 3 the value f ₀ reflect the change in the position of the movable composite mass 2 relative to the support surface.

If the motion stabilization system is switched on, the hydraulic cylinder 3 communicates with the device for absorbing dynamic loads 4 with the specified elastic-damping properties (Fig. 1). When hitting a single unevenness, there is a synchronous deflection of the housing 1 and the movable component 2 relative to the horizon, and the movable component 2 due to the communication of the hydraulic cylinder 3 with the device for absorbing dynamic loads 4 also still rotates on the hinge 10 relative to the housing 1 (Fig. 1). FIG. 4 shows the changes in ϕ _C and ϕ _0-C and it can be seen that there is a stabilization of the movement of the body 1 and the oscillations of the rolling component 2 due to the absorption of the dynamic load by the stabilization system operating according to the prototype principle. Despite the difference in the vibration frequencies of the body 1 on the elastic tires and the movable component 2 relative to the body 1, there is no resonance between these oscillating parts, since the device for absorbing dynamic loads 4 dampens the oscillatory process until the direction of movement of the oscillating masses of the TTM may coincide (Fig. 4). Thus, the stabilization system with a constant level of elastic-damping properties is effective when hitting single irregularities.

In the case of a continuous movement of the TTM on a road with irregularities with the stabilization system turned on, having a constant level of elastic-damping properties, the vibrations of the body 1 and the movable component 2 relative to the body have different frequencies. In this case, a moment in time always arises when the directions of oscillations of the housing 1 and the movable component 2 coincide, a resonance occurs, accompanied by a sharp increase in the acting dynamic loads on all structural elements of the TTM and the operator (Figs. 5-6).

The principle of operation of the developed stabilization system is based on the operational change in the rigidity of the device for absorbing dynamic loads 4, depending on the angle of rotation of the rolling component relative to the body (ϕ _0-C ). The creation of a stabilization system with variable elasticity is possible on the basis of gas springs with a variable structure. Under the variable structure we mean the variable volume of the cavity of the gas springs due to the use of two or more similar devices connected to the hydraulic cylinder 3 by means of individual controlled throttles 5.

The working process of the developed stabilization system assumes that during continuous movement on the road with irregularities of the TTM with such a system, its body 1 oscillates on elastic tires, and the movable component 2 oscillates relative to the body 1 due to hinges 10, 11 and 12, as well as due to the connection hydraulic cylinder 3 through open controlled throttles 5 with gas springs 6. Position sensors of the rolling component 8 continuously register and transmit the values of ϕ _0-C to the control unit 7, installed with the possibility of calculating and transmitting the control signal to the variable throttles 5.

At the moment preceding the resonance, there is a coincidence of the directions of movement of the body 1 and the movable component 2, which leads to an increase in ϕ _C and ϕ _0-C . In this case, the position sensor of the movable component 8 relative to the housing 1, which has the ability to determine the value of ϕ ₀ . _C and transmitting signals, determines and transmits to the input to the control unit 7 the values ϕ _0-C . The control unit 7, based on the algorithm embedded in it, determines the difference between the current position of the rolling component 2 and the maximum permissible for these conditions. If the current position exceeds the maximum permissible, then the control unit 7 through its output gives a control signal to the controlled throttle 5, which provides partial or complete blocking of the flow of the working fluid from the hydraulic cylinder 3 to the gas springs 6 through the pipeline 9.

Thus, at the moment preceding the onset of resonance, the control unit 7 sends a signal to the controlled throttles 5, which overlap one or more gas springs 6 of the device for absorbing dynamic loads 4, which leads to an increase in the rigidity of the device for absorbing dynamic loads 4 and, as a consequence, to an increase in the natural vibration frequency of the movable component 2 relative to the housing 1, as well as a decrease in the vibration amplitude of the movable component 2 relative to the housing 1. The movable component 2 earlier reaches the extreme position and begins to move in the opposite direction even before the housing 1 reaches the extremum of the inclination angle (Fig. . 7).

When the extremum ϕ _{0-C is} reached, the movable component 2 begins to move in the opposite direction, which fixes the position sensor of the movable component 8 relative to the housing 1 and transmits the values of ϕ _0-C to the control unit 7, which in turn transmits the control signal to the controlled throttles 5, which open and communicate the hydraulic cylinder 3 with all gas springs 6, which is necessary to increase the amplitude of oscillations of the movable component 2, accumulate kinetic energy, which will subsequently be absorbed in subsequent oscillatory cycles.

Thus, the timing of the moment of reaching the extreme positions of the movable component 2 and the housing 1 occurs, as a result, the elimination of resonances and stabilization of the TMM motion due to the absorption of the vibration energy by the stabilization system.

The applicant has developed mathematical and simulation models, with the help of which the efficiency and operability of the proposed method for stabilizing TTM have been substantiated by the example of a self-propelled forage harvester with a movable component in the form of a hinged adapter. By means of simulation, oscillograms of changes in the angles of the longitudinal inclination of the harvester body (Fig. 8) and the angles of rotation of the rolling component in the form of a hinged adapter (Fig. 9) when the harvester moves along a dirt road at a speed of 15 km / h are constructed, from which it can be seen that stabilization the body of the machine according to the proposed method allows to reduce the peak values of the vibration parameter by more than 2 times.

The implementation of the described method makes it possible to reduce the dynamic loads acting on the machine and its operator by absorbing the vibration energy due to the communication of the hydraulic cylinder, which ensures the mobility of the component movable part, and a device for absorbing dynamic loads with variable stiffness.

Claims (1)

A system for stabilizing the movement of self-propelled transport and technological machines, containing a hydraulic cylinder with a device for absorbing dynamic loads, including elastic and damping elements, characterized in that it additionally contains a control unit and a position sensor of the moving component relative to the machine body, the output of which is connected to the input of the control unit, and the elastic element is made in the form of two or more gas springs with damping elements installed on each of them in the form of controlled throttles connected to the output of the control unit, while each of the gas springs is connected by pipelines through controlled throttles to a hydraulic cylinder.

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