EP1396642A1 - Method of controlling a pneumatic or hydraulic actuator - Google Patents

Abstract

The procedure for the control of a pneumatically or hydraulically operated actuator (2) is such that different movement phases of the actuator are initiated in dependence upon the distance covered by its piston (4), and the movement phases are controlled only through the application and release of a fluid pressure acting upon the piston. The beginning and/or end of one or more accelerating and/or braking phases are determined in dependence upon the distance covered. An Independent claim is included for a device for the operating of a pneumatically or hydraulically operated actuator in which a control unit can initiate different movement phases of the piston in dependence upon distance covered by the piston.

Description

The invention relates to a method for controlling a pneumatic or hydraulically operated actuator and a device for Operating a pneumatically or hydraulically actuated actuator.

Important, for example, when controlling the movement of the pistons of pneumatic working cylinders is the end position damping. This should Impacts with the fastest possible movement from one end position to the avoid others. The easiest known system to achieve Such end position damping is more mechanical Damper. However, they have the disadvantage that they cannot be used flexibly are, since they are each optimized for a certain moving mass are to absorb their kinetic energy on impact. additionally such dampers are subject to wear and require one additional space requirement near the cylinder. Similar disadvantages have air chambers integrated in the cylinder with variable outlet openings. These are also not flexible because they are specific to each moving mass can be adjusted.

A known electronic end position damping is said to have these disadvantages eliminate at which a speed ramp is specified, which is regulated by a continuously operating, linear controller becomes. However, this system has the disadvantage that it is due to the required proportional valves is relatively expensive. Furthermore, are also at this system limits the tolerated changes in the moving mass, since they may not exceed 30%. Furthermore, this continues System a certain, in particular symmetrical structure of the Cylinder, the piston and the supply structure ahead.

It is an object of the invention to provide an improved control method a pneumatically or hydraulically actuated actuator and a corresponding one To create a device which has an improved end position damping enable. This task is accomplished through a process with the features specified in claim 1 and by a device solved with the features specified in claim 18. preferred Embodiments result from the respective subclaims.

According to the method according to the invention, the different Movement phases of the actuator, for example acceleration and braking phases depending on the piston of the actuator controlled distance. However, this takes place within the individual phases are not controlled by proportional valves, rather, the movement phases are only switched on and off a fluid pressure acting on the piston or a fluid differential pressure controlled. This is the fluid pressure around a predetermined supply pressure. It is therefore possible to Control, in particular a closed loop control solely via switching valves to effect, which simplifies the construction of the entire system. The actuator to be controlled can be any one Actuator, for example a cylinder or rotor with corresponding designed piston act. For a rotor this corresponds to traveled distance of a rotation, i.e. an angle. The method is, for example, in the case of actuators acting on one or two sides or cylinders with or without piston rod applicable. at A single-acting actuator will only have one side with a fluid pressure acted upon, preferably in the opposite direction a spring force acts. The control of the individual movement phases depending on the adjustment path enables the actuator or a piston of the actuator targeted at any position and preferably to stop steamed. So it is possible in one cylinder for example, to approach and hold intermediate positions.

Preferably the beginning and / or end of one or more accelerating and / or braking phases depending on the distance traveled Path determined. This enables the corresponding movement phases depending on the adjustment path or angle of the cob initiate that an optimal cushioning is achieved. On a further regulation, in particular pressure regulation during the individual Phases are omitted. The control and end position damping is only achieved by controlling the switching times.

The waypoints or angles at which the Phases are ended and / or started depending on a mass index of the mass to be moved. The mass index is a value which is proportional to the particular to be moved Mass is and enables the system and in particular the Adjust end position damping to different masses.

The start and / or end of the individual phases is preferred current system parameters adjusted. In this way, an adaptive Control can be created, which enables the control of the actuator, for example a drive cylinder during this Operation in different environmental conditions, e.g. B. different masses to be moved. For example it is possible, the control system first with an unspecific parameter set deliver and the exact for the respective drive system specific parameters during the first operation, e.g. while one or more learning trips with the unspecific parameter set derived from the behavior of the drive system. Alternatively, you can the individual phases of the movement control of the piston according to preset Sections of the adjustment path can be started. A Such a setting is particularly important when the Cylinder or actuator selected, this then according to a fixed predetermined program is controlled. Doing so may be a possibility be provided, various programs on a control device select which to use on different actuators or drive cylinders or their areas of application are adapted. In particular it is conceivable different programs for different to be moved To provide masses, which before commissioning the controller Program is selected, which of the mass to be moved comes closest.

The current system parameters preferably include the piston position, the fluid pressure, the time and / or derived from these quantities Sizes. Preferably, the supply pressure can be adjusted accordingly Sensors are detected. The piston position can by known Displacement sensors, e.g. incremental encoders or potentiometers respectively. The evaluation and adaptation of the behavior-determining System parameters are preferably carried out only once during a movement process, preferably at the end of the movement process. Based on the acquisition and evaluation of the current system parameters can both the current, currently running movement as well as the subsequent movements of the piston be adjusted accordingly by shifting the beginning or End of the respective movement phase.

The system is preferably designed such that the mass index of the mass to be moved is determined automatically by the system. This enables automatic adjustment of the system or control to different masses to be moved without corresponding Adjustment or programming work is required. This provision the mass index is not based on the previously described method limited, rather such an automatic detection of the mass index also for other control procedures for pneumatic or hydraulic actuators are used.

The mass index can preferably be based on the accelerations that have taken place and / or speeds of the piston in one preferably path interval determined independently by the system or after a predetermined one Period of time can be determined. The one currently to be moved In principle, mass can be derived from the acting forces, i.e. H. the acting one Press and the occurring acceleration of the piston is determined become. However, since it is difficult to determine the mass required To determine sizes precisely at any time and in particular the friction that occurs is difficult to take into account, can alternatively only be a mass index from the quantities mentioned be determined which is the relationship between different moving Represents masses. If the fluid pressure is known, this can be done Acceleration can be determined by that at a particular Position or after a certain time after the start of acceleration the speed of the piston is determined. The speed again, by measuring the length of time the piston takes to cover the distance between two waypoints become. Depending on the determined mass or the determined Mass index can then the individual phases of the movement of the Pistons can be controlled. In the controller, values for certain Masses, e.g. for the minimum and maximum mass, and in particular the times for the start of each braking and / or damping phases can be specified, from which then for the currently determined mass or the currently determined mass index the respective values or times are interpolated. However preferred the respective start and end points for the individual movement phases currently based on the determined mass index calculated.

The method according to the invention is particularly suitable for control the movement of a piston of a double acting, in particular pneumatic actuator, such as a drive cylinder. The method particularly concerns the end position damping of the piston in the cylinder. A first, accelerating phase is provided for this, in which a sliding chamber on a first side, d. H. on the rear side of the piston is ventilated. At the same time, a braking chamber on the opposite Side, d. H. on the front of the Piston vented. This increases the pressure in the pushing Chamber as the pressure in the braking chamber decreases can. Because of this pressure drop, a force is exerted on the piston generated, which accelerates this. When the piston is in motion the volume of the pushing chamber increases, while reducing the volume of the braking chamber. On the acceleration phase, in which the piston in a certain direction is set, at least one first braking phase follow in which the pushing chamber continues ventilated and the braking chamber is closed. This will achieves that the fluid trapped in the braking chamber or the air trapped in the first braking chamber this cannot escape. The further movement of the piston causes that the volume of the braking chamber is reduced, whereby the fluid in the brake chamber is compressed and the pressure continues to rise in this chamber. The pressure in the braking increases Chamber on the supply pressure, which of a Compressed air source for actuating the cylinder is generated. Thus increases the pressure in the braking chamber so far that it is higher than that Pressure in the sliding chamber is. This creates a force which works against the direction of movement of the piston and which reduces the kinetic energy of the piston. When the pressure in the braking Chamber would rise too much, the force opposed the desired direction of movement, will be sufficient at some point, to reverse the movement of the piston so that it opposes itself the desired direction of movement. The piston would start to swing. To prevent this, the Pressure in the braking chamber is reduced or constant again being held. This is done by braking in at least one second Phase closed the pushing chamber and the braking chamber ventilated. By ventilating the braking chamber, a Connection of the braking chamber with the compressed air supply established. As explained in the braking chamber, however, there is a pressure there is higher than the supply pressure, the air flows from the braking chamber now back into the supply line. this has opposite the ventilation of the braking chamber to the environment the advantage that the fluid or air from the braking chamber escapes more slowly and the piston is braked further. Would If the braking chamber is vented to the environment, the air could or the fluid escape very quickly, causing the piston to come back would be accelerated. The backflow of the fluid from the braking end Chamber in the supply line has the further advantage that the air or the fluid is not lost, so that the air consumption of the system can be reduced. The method according to the invention thus enables targeted with a simple construction and effective cushioning of a piston at the same time reduced air consumption. The method according to the invention needs no proportional valves for its execution, they are only Switching valves required because the two chambers, i.e. H. the pushing and the braking chamber, either completely closed or the end or ventilation lines are fully open. There is an adjustable throttling effect in the ventilation lines not desired and not required. Even if the procedure here The method can be described for a pneumatic cylinder also apply accordingly to a hydraulic cylinder, but then the influence of the compressibility of the fluid cannot be exploited.

A damping phase is preferably additionally provided, in which both the pushing and the braking chamber are ventilated. This damping phase follows the second braking phase on. In this phase the pushing chamber is ventilated again ensure that the force is against the direction of movement does not act on the piston for too long. By re-venting The pushing chamber becomes the pressure difference between the two Chambers again decreased. At the same time, the fluid is braking in the Chamber continues to be fed back into the supply line since the Pressure in the braking chamber continues to be higher than the supply pressure is. By providing this damping phase, an optimized Damping of the piston when it reaches its end position become.

Furthermore, there is preferably at least one pressing phase in the method provided in which the pushing chamber is ventilated and the Braking chamber is vented when the piston is close to one End position. This setting means that the Piston reached in the end position, because by venting the pushing and venting the braking chamber a maximum pressure difference between the two chambers and thus a maximum force the piston is generated. This force pushes the piston into its end position, whereby it achieves the best possible hold there.

This pressing phase preferably follows the damping phase. D. H. after the piston has reached its end position, it is damped kept active there.

According to the invention, the individual phases are dependent on the adjustment path of the piston started. The adjustment path is known by Position transducers, e.g. incremental encoders, recorded and from a control device for starting the individual movement phases considered accordingly. By being in certain positions the braking phases of the adjustment path are initiated, it can be ensured that the piston reaches its end positions is optimally damped and not with too high a kinetic Energy reaches the end position. Furthermore, the maximum acceleration can simultaneously of the piston can be reached and ensured that the piston does not stop before reaching the end position.

With increasing mass, the transition from the accelerating is preferred Phase shifted to the braking phase, d. H. the braking phase is earlier, after a shorter adjustment of the Piston initiated. The system thus the phase transitions independently to the current crowd. With greater mass, the moving Pistons also have higher kinetic energy, making an earlier one Braking is required. This can be the moving mass or a for this representative mass index during the currently running movement or determined during a previous movement of the piston become. For example, the piston can be controlled at a first Movement take place according to a maximum mass and during this movement the current mass can be determined so that in subsequent Piston movements control the appropriate mass can be adjusted and the transition point from the accelerating Phase selected corresponding to the first braking phase can be. The transition from the first braking phase to the second braking phase should depend on the current system parameters and especially the current mass. It is it is important that the feedback of the pressure from the braking Chamber in the supply line starts on time. At dead time of the valves, the signal to switch on must preferably be taken into account the venting valve of the braking chamber before the actual one Exceeding the supply pressure in the braking Chamber are given. Otherwise it would be in the braking chamber built up such a high pressure, which would be sufficient, the direction of movement reverse. To control the transition of the first braking phase to the second braking phase can for example the derivation of the force occurring can be used, if this exceeds a predetermined threshold, from the first braking phase passed into the second braking phase becomes. The duration of the second braking phase is again dependent from the moving mass. At high mass, this phase can be due the greater kinetic energy and inertia last longer.

Furthermore, the transition from the accelerating phase to the braking phases, d. H. advanced to the first braking phase, if the piston is too large when it hits an end position has kinetic energy. That is, if during a first movement of the piston is found to be when it reaches the End position has too much kinetic energy and an undesirable one Shock is generated during a second movement the control set up so that the transition from the accelerating Phase to the braking phase after a shorter adjustment distance the piston, d. H. takes place earlier.

Conversely, the transition from the accelerating phase to the braking phases preferably shifted backwards if the Piston stops before reaching an end position. If with a first movement the piston is found to be braking too early is and does not reach its end position, can with subsequent movements the control can be set up so that the braking Phases only after a longer adjustment travel of the piston, d. H. later be initiated so that the piston reaches the specified end position.

Furthermore, the transition to the pressing phase is preferably controlled in such a way that that the transition to the pressing phase is advanced if the piston swings back when the end position is reached. By early active holding of the piston at which the maximum Pressure difference between the pushing and braking chamber prevails, swinging back of the piston can be prevented because this with the maximum possible force due to the pressure difference is pressed against the end position between the chambers.

The control of the actuator or piston can more preferably be dependent the direction of movement. So can for the two possible directions of movement with a double-acting actuator different cylinders are provided his. For example, piston surfaces of different sizes can be used be taken into account.

In a further preferred method variant, the piston is forward its movement, d. H. before the start of the accelerating phase Ventilation of the chambers biased on both sides of the piston. You can do this for example, the chambers are ventilated until about Half of the supply pressure prevails in both chambers. Through the Preload is achieved that the system is less sensitive to short switching cycles react and less tendency to vibrate. alternative or in addition, the piston can start before the accelerating phase be brought into a start position at one end of the cylinder.

In this starting position, the piston is preferably kept active, i.e. H. the piston is pressed against the corresponding end position. there the holding force acts against the direction of movement of the following movement taking place. This causes the beginning of the acceleration phase ambient pressure in the pushing chamber and in the braking chamber supply pressure prevails. If during the acceleration of the piston moves, the volume also decreases the braking chamber and increases the volume of the sliding chamber. This ensures that the pressure in the Chambers only increases or decreases comparatively slowly, so that during of the entire acceleration process always a high one Pressure level prevails in the entire system, which has a positive effect on controllability of the process or movement.

The invention further relates to a device for operating a pneumatically or hydraulically operated actuator. In the actuator at least one path measuring device for detecting at least one waypoint a piston is provided. With the path measuring device it can are a known position measuring system, which is constantly or continuously determines the position of the piston or only predetermined ones discrete piston positions recorded. If a predetermined piston position and the speed of the piston are known, the further waypoints which are used to control the movement phases of the Pistons are relevant, over which elapsed time can be determined. It This makes it possible to use a few position sensors to make the actuator dependent to control its adjustment path. It is also according to the invention a chamber is provided on at least one side of the piston, which Fluid pressure can be applied via at least one switching valve and is relaxing from this. That means the given fluid pressure is only switched on and off, i.e. in the case of pneumatics the chamber is only ventilated. Only a given one can do this Pressure, i.e. a supply pressure is applied, a Pressure control to control the movement of the piston does not take place. In addition, a control module is provided, which the different Phases of movement of the piston depending on it Initiates adjustment path. The control of the individual movement phases The switching valves are used in the above Wise.

For example, the device is used to operate or move a double-acting, in particular pneumatic actuator or drive cylinder. The double-acting drive cylinder has a known Way two arranged on opposite sides of a piston Chambers, each of which can be ventilated and vented via at least one valve are. A control module is also provided, via which the Valves are operated and which is set up the movement of the piston according to the method explained above with its preferred Control variants. The device according to the invention has a simple setup because it uses inexpensive standard components gets along and the required end position damping during the movement of the piston in the drive cylinder only by one in the Control module stored in hard or software control program is achieved. The valves are designed as switching valves. This simplifies construction and reduces the cost of the device. at The switching valves are applied using the method according to the invention not pulsed easily. This would wear out a lot of the valves and also do not cause rapid acceleration allow the piston because the acceleration due to the dead times the valves would only be braked. The maximum acceleration and maximum speed comes with a minimum number of switching operations, which also increases the valve life becomes.

The device according to the invention preferably has individual modules which control, in particular closed loop control or Take control of individual movements of the piston. So is preferably a parking module is provided which controls the valves, to put the piston in a parking position. This parking position is preferably a starting position in an end position of the cylinder, in which the piston is kept active. To keep active, the Pressurized chamber of the piston facing away from the end of the cylinder, while the chamber is at the end of the cylinder facing side of the piston is vented. This will make the piston pressed against the end of the cylinder with maximum force.

Alternatively or additionally, a start module is provided, which the Controls the preload of the piston before it moves. For preload of the piston, as explained above, the chambers on both Sides of the piston are pressurized to keep the piston moving better control or control. This toughening and in particular the amount of pressure applied for preloading we are controlled by the start module.

Furthermore, the control module preferably assigns a separate module End position damping, which accelerates and brakes controls the piston. The module for cushioning takes over thus the control of the acceleration and the Braking the piston in the manner described above, i. H. it directs the acceleration phase, the braking phases, the damping phases Phase and / or the pressing phase and monitors them. A storage device for is also preferred in the device Storage of the control parameters provided. So those in previous Movements of the piston determined current System parameters are stored in this memory for subsequent Control movements accordingly. alternative can from the determined system parameters, for example the mass to be moved, first corresponding control parameters such as the start of the braking phase and are stored in the memory. In subsequent Movements of the piston then these values from the Memory read out and the piston from the control module and in particular controlled according to the module for end position damping or regulated. Furthermore, predefined in the memory Control parameters or programs can be stored, which is independent from the currently determined system parameters for control of the piston can be accessed, for example, when commissioning to control a first sequence of movements of the piston.

Fig. 1

schematisch den Aufbau der erfindungsgemäßen Vorrichtung zum Betreiben eines Antriebszylinders und

Fig. 2

schematisch den Aufbau des erfindungsgemäßen Steuerungsmoduls.

The invention is described below by way of example with reference to the attached figures. In these shows:

Fig. 1

schematically the structure of the device according to the invention for operating a drive cylinder and

Fig. 2

schematically the structure of the control module according to the invention.

The device according to the invention is used to control or actuate of a double-acting pneumatic drive cylinder 2. Inside of the drive cylinder 2, a piston 4 is arranged, which in the usual Way with one or two piston rods to move external, here facilities not shown is connected. The piston 4 is of both Sides can be pressurized so that it becomes a front cylinder chamber 6 and a rear cylinder chamber 8 at opposite Formed sides of the piston 4. The piston 4 is also in a known manner with a position detection device 10, for example an incremental encoder connected to the position of the piston 4 inside the To be able to determine cylinder 2.

The front cylinder chamber is with a ventilation valve 12 and one Vent valve 14 connected. The rear cylinder chamber is corresponding 8 with a ventilation valve 16 and a ventilation valve 18 connected. The ventilation valves 12 and 16 are connected to a supply line 20 in connection, which is connected to a compressed air source is.

There is also a pressure sensor 22 for determining the pressure in the front Cylinder chamber 6, a pressure sensor 24 for determining the pressure in the rear cylinder chamber 8 and a pressure sensor 26 for determining of the pressure in the supply line 20 is provided. The valves 12, 14, 16 and 18 are preferably electrical by a control unit 28 actuated. The position detection device 10 and the three Pressure sensors 22, 24 and 26 are also connected to the signal lines Control unit 28 connected so that the control unit 28 information about the pressure in the front cylinder chamber 6, the rear cylinder chamber 8 and in the supply line 20 and on the position the piston 4 receives. The control unit 28 can also be an input device 30 for input of commands or data by a user which have for communication with other control devices. The Input device 30 can be a keyboard or unidirectional or bidirectional Interface be formed.

The movement of the piston 4 in the cylinder 2 in the X direction takes place according to the following control procedure, which is a cushioning of the piston 4 in the cylinder 2 when the end position 32 is reached. When moving in the direction X, the rear cylinder chamber 8 forms the pushing and the front cylinder chamber 6 the braking chamber. 1 shows a position of the piston 4 between the end positions 32 and 34, d. H. while moving. Before the movement begins Piston 4 in the X direction, the piston 4 is preferably biased, by the front cylinder chamber 6 and the rear cylinder chamber 8 are pressurized. This can cause an undesirable Swinging of the piston 4 can be avoided. Alternatively or then the piston 4 is preferably first in the end position 34 moved or kept active in this by the front cylinder chamber 6 is ventilated and the rear cylinder chamber 8 is vented. When venting and venting, note that the valves 12 to 18 are pure switching valves, which have only two states, namely have opened and closed. Instead of for every cylinder chamber a vent valve and a vent valve, d. H. four 2/2-way switching valves two 5/3-way or two 3/3-way valves can also be provided are provided, which aerate and vent the cylinder chambers 6 and 8. These valves also each point to the ventilation process only two switching states, namely line open and line closed on. It is important that the cylinder chambers 6 and 8 over the Valves can be closed completely.

From the end position 34, the piston 4 is accelerated in the X direction by the rear cylinder chamber 8 by opening the exposure valve 16 is ventilated. At the same time, the front cylinder chamber 6 is opened of the vent valve 14 vented. This leads to an increase in pressure in the rear cylinder chamber 8 and to a pressure drop in the front Cylinder chamber 6, whereby the piston 4 accelerates in the X direction becomes. The movement or position of the piston 4 in the direction X is detected by the position detection device 10. To The control unit 28 ends the described in a predetermined adjustment path Acceleration phase and begins the first braking phase. For this purpose, the vent valve 14 of the front cylinder chamber 6 is closed. This causes the pressure of the fluid in the front Cylinder chamber 6 with further movement of the piston 4 in the direction X increases because the volume of the front cylinder chamber 6 decreases. The pressure in the front cylinder chamber 6 generates an increasing counterforce, which acts on the piston 4 and that generated by the pressure in the rear cylinder chamber 8 Counteracts force. This slows down the movement the piston 4.

Furthermore, the pressure in the front cylinder chamber 6 rises quickly about the level of pressure in the supply line 20. As soon as the pressure in the supply line 20, which from the pressure sensor 26 is detected, exceeded or shortly before this threshold value is reached, the control unit 28 begins the second braking phase. In the second braking phase, the ventilation valve 16 of the rear cylinder chamber 8 closed and the ventilation valve 12 of the front cylinder chamber 6 open. By doing that at the time in the front Cylinder chamber 6 there is now a pressure which is greater than that Pressure in the supply line 20, the front cylinder chamber 6th vented via the supply line 20. This venting takes place relatively slow because of the pressure difference between the front cylinder chamber 6 and the pressure in the supply line 20 is relatively low. The venting thus takes place much more slowly than it does via the vent valve 14 would take place to the environment. Through this slow venting the front cylinder chamber 6, the movement of the piston 4th braked further in the X direction.

After a further adjustment of the piston 4 in the direction X, which is detected by the position detection device 10, the ends Control unit 28 the second braking phase and begins a damping phase, in which the ventilation valve 16 for the rear piston chamber 18 is opened again. As a result, the rear cylinder chamber 8 pressurized again, preventing the force generated by the pressure in the front cylinder chamber 6 becomes large that the piston 4 moves back against the direction of movement X. becomes. This can prevent the piston from swinging back become.

After a further adjustment in the X direction, the control unit 28 initiated a pressing phase in which the ventilation valve 12 of the front cylinder chamber 6 closed and the vent valve 14 of the front cylinder chamber 6 is opened. simultaneously the rear cylinder chamber 8 is further ventilated. This will make the Piston by the maximum pressure difference between the front cylinder chamber 6 and the rear cylinder chamber 8 against the end position 32 pressed and kept active at this end position.

The acceleration and braking process of the piston 4 was here for described a movement in the X direction. For a movement Acceleration and deceleration take place against this direction accordingly, with the rear cylinder chamber 8 as braking and the front cylinder chamber 6 serves as a pushing chamber.

As described, the entire braking and damping process can to achieve end position damping when the piston moves 4 by a few switching operations of the switching valves 12, 14, 16 and 18 can be achieved. There is no pulsing of the switching valves, rather only a minimum number of switching operations is used. This enables maximum acceleration and maximum speed of the piston and reduces valve wear.

The times or waypoints along the travel path in the direction X on which the individual braking and damping phases started are, by the control unit 28 either after a predetermined, for example entered via the input device 30 or set program or depending on system parameters, which is determined by sensors 10, 20, 22 and 24 be determined. In particular, the moving mass or a value that is representative of the moving mass is taken into account, since at a large moving mass due to its greater kinetic energy earlier braking is required than a lower one moving mass. The system parameters are during the motion process currently to be controlled or in previous ones Movements are determined so that the system starts operating current system parameters are adjusted. So it can be a very precise control or regulation also for differently moved Masses are reached. The moving mass can vary by 100%. Furthermore, the control system can be connected to any system configuration, d. H. used pneumatic components, in particular also Cylinder with one - sided piston rod, rodless cylinder and Part-turn actuators, different moving masses and operating positions be adjusted. In the control unit 28 can for certain masses predefined braking points can be stored, which previously were determined experimentally. In operation, you can then on the basis of the determined system parameters for a specific determined moving mass the right braking points with the help of a fuzzy system be approximated. In doing so, intermediate values between the saved Approximates values, which is the ratio between reflect moving mass and braking point.

2 schematically shows the structure of the control module according to the invention or the control unit 28 according to the invention Damping procedure is briefly called NEED procedure, i.e. H. referred to as neuro-fuzzy electronic end position damping. The Control module receives user input via the input device 30. Furthermore, the sensors 10, 20, 22 and 24 (see Fig. 1) connected. The control unit 28 actuates the as actuators Switching valves 12, 14, 16 and 18, which have been explained with reference to FIG. 1. The control module 28 or the control unit 28 has three modules 36, 38 and 40. The first module 36 is a parking module, which serves the piston 4 preferably in a predetermined parking position at one of the end positions 32 and 34 before the start of the acceleration phase bring to. There is only a slow movement, which by pulsing the ventilation valve 12 or 16 depending on the direction of movement of the piston 4 is reached. The second module 38 is the module for End position damping or the NEED module, which the previously described Control or regulation for accelerating and braking the piston 4 executes. The third module 40 is a start module 40, which the described biasing of the piston by ventilation controls both cylinder chambers 6 and 8. Superordinate over these three Modules 36, 38 and 40 is a metasystem 42 which is based on the values determined by sensors 10, 20, 22 and 24 and by user information decides which of the three modules 36, 38 and 40 is activated should be to operate the actuators 12, 14, 16 and 18.

Even if the method according to the invention uses the example of a linear one Pneumatic cylinder has been described, the method can be used accordingly also with other pneumatic or hydraulic actuators, for example use rotors. Furthermore, the procedure also applicable to single-acting actuators in which the Fluid pressure acts against a spring force.

reference numeral

2

cylinder

4

piston

6

Front cylinder chamber

8th

Rear cylinder chamber

10

Position detection system

12, 16

ventilation valves

14, 18

vent valves

20

supply line

22, 24, 26

pressure sensors

28

control unit

30

input device

32, 34

end positions

36

Park module

38

NEED module

40

start module

42

metasystem

X

movement direction

Claims (23)

Method for controlling a pneumatically or hydraulically operated Actuator in which different phases of movement of the actuator depending on the distance traveled at least one piston are initiated and the movement phases only by turning one on and off on the piston acting fluid pressure can be controlled. The method of claim 1, at which start and / or end one or more accelerating and / or braking Phases can be determined depending on the distance traveled. The method of claim 2, wherein the waypoints at which the phases are ended and / or started depending on determined by a mass index of the mass to be moved become. Method according to one of the preceding claims, in which the beginning and / or end of the individual phases to current System parameters is adjusted. The method of claim 4, wherein the current system parameters the piston position, fluid pressure, time and / or off derived sizes from these sizes. Method for controlling a pneumatically or hydraulically operated Actuator in particular according to one of the preceding Claims in which a mass index of those to be moved Mass is determined automatically by the system. The method of claim 6, wherein the mass index is from accelerations and / or speeds of the Piston in a particular one which is preferably determined independently by the system Path interval is determined. Method according to one of the preceding claims, in which the actuator is a double-acting, in particular pneumatic actuator, and
at least one accelerating phase in which a pushing chamber (8) is ventilated on a first side of the piston and a braking chamber (6) on the opposite side of the piston (4) is vented,
at least a first braking phase in which the pushing chamber (8) is ventilated and the braking chamber (6) is closed, and
at least a second braking phase is provided, in which the pushing chamber (8) is closed and the braking chamber (6) is aerated. Method according to claim 8 with at least one damping phase, in which both the pushing (8) and the braking Chamber (6) are ventilated. Method according to claim 8 or 9 with at least one pressing phase, in which the pushing chamber (8) is ventilated and the braking chamber (6) is vented when the piston is located near an end position (32). The method of claim 9, wherein the pressing phase on the dampening phase follows. A method according to any one of claims 8 to 11, in which the Transition from the accelerating phase to the braking phase Phases are advanced with increasing mass. Method according to one of claims 8 to 12, wherein the Transition from the accelerating phase to the braking phase Phases is advanced if the piston (4) hits when an end position (32) has an excessive kinetic energy. Method according to one of claims 8 to 13, wherein the Transition from the accelerating phase to the braking phase Phases is shifted backwards if the piston (4) reaches before an end position (32) stops. A method according to any one of claims 8 to 14, in which the Transition to the pressing phase is advanced if the piston (4) swings back when the end position (32) is reached. Method according to one of the preceding claims, in which the control of the actuator (4) depending on the direction of movement (X) takes place. Method according to one of the preceding claims, in which the piston (4) before its movement by venting the Chambers (6, 8) is biased on both piston sides. Device for operating a pneumatically or hydraulically actuated actuator, at least one displacement measuring device for detecting at least one waypoint of a piston being provided in the actuator,
a chamber is provided on at least one side of the piston, which can be acted upon by a fluid pressure and relieved of this by at least one switching valve, and
a control module is provided which can initiate different phases of movement of the piston depending on the distance traveled by the piston. Device according to claim 18 for operating a double-acting especially pneumatic drive cylinder (2) with two arranged on opposite sides of a piston (4) Chambers (6, 8) which each have at least one valve (12, 14, 16, 18) can be aerated and vented, a control module (28) is provided, which is set up the movement of the piston (4) by means of a method according to one of claims 8 to 17 to control. Device according to one of claims 18 or 19, wherein the control module (28) has a parking module (36) which the valves (12, 14, 16, 18) controls to move the piston into (4) a parking position bring to. Device according to one of claims 18 to 20, wherein the Control module (28) has a start module (40), which the Preload of the piston (4) controls before its movement. Device according to one of claims 18 to 21, wherein the control module (28) a module (38) for end position damping which has the acceleration and deceleration of the Piston (4) controls. Device according to one of claims 18 to 22, wherein a non-volatile memory for storing the control parameters is provided.

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