DE102017117000A1 - Method for controlling an actuator and actuator - Google Patents

Abstract

Method for controlling a fluidically actuated actuator (10), wherein the actuator (10) has at least one piston (12) which delimits at least two chambers (14, 16) and an actuator (18) which depends on the distance traveled by the actuator Piston (12) is movable in different movement phases, wherein the chambers (14, 16) are independently ventilated or vented by switching on and off of a fluid pressure, and wherein in an acceleration phase of the actuator (18) the sliding chamber (14, 16) ventilated and braking chamber (16, 14) is vented, characterized in that the braking phase comprises a fluidic braking phase and a mechanical braking phase, wherein the switching on and off of the fluid pressure in the fluidic braking phase is such that the sliding chamber (14, 16 ) is vented and the braking chamber (16, 14) is vented, and that adjoins the fluidic braking phase, the mechanical braking phase in which a Abbre msung by means of a mechanical damper (30).

Description

The invention relates to a method for controlling a particular pneumatically actuated actuator. Actuators may be in particular pivoting or linear units, which are used in handling technology. Such an actuator has at least one piston which delimits at least two chambers and an actuator which can be moved in different movement phases as a function of the distance traveled by the piston. The chambers are independently ventilated or vented by switching on and off of a fluid pressure, wherein the sliding chamber is vented in an acceleration phase and the braking chamber is vented.

Such a method and an actuator performing the method is for example from EP 1 396 642 A1 known. There, a braking phase is described in which the braking chamber is closed and vented until the piston comes to a standstill. Ventilation in the chamber has the advantage that sufficient damping can be provided; however, reacts with changing, provided on the actuator masses not linear.

Another, similar process is from the DE 10 2016 107 407 A1 known.

The present invention is based on the object to further develop the method described above and to shorten the braking phase with suitable damping.

This object is achieved by a method having the features of patent claim 1. Accordingly, it is provided that the braking phase comprises a fluidic braking phase and a mechanical braking phase, wherein the switching on and off of the fluid pressure in the fluidic braking phase takes place in such a way that the sliding chamber vents and the braking chamber is vented, and that after the initiation of the fluidic braking phase, a mechanical braking phase is performed, in which the actuator is braked by means of a mechanical damper. The braking by means of the mechanical damper takes place via a suitable, in particular specifiable braking distance, which is significantly greater than zero. Advantageously, the design is such that more than half of the total braking distance relates to the physical braking phase and that the mechanical damper preferably comes into play only at the end of movement of the actuator.

Suitable mechanical dampers are, for example, elastomers, suitable spring units, spring pillows, for example of base material or metal, or also hydraulic damper units.

The division of the braking phase in the fluidic and in the mechanical braking phase has the advantage that is first braked fluidly. Here, a bumpless delay of the actuator can be achieved by appropriate venting and venting the chambers. In the mechanical braking phase, in which the piston, the actuator or intermediate links strike the mechanical damper, a high deceleration power can be provided, which is preferably also largely or completely shock-free. While in the fluidic braking phase almost no wear on the components occurs, the invention takes during the mechanical braking phase wear in the mechanical damper in order to provide a suitable, high deceleration performance can. It has been found that the combination of a fluidic braking phase and a mechanical braking phase according to the invention is particularly advantageous and leads to short cycle times.

Overall, this makes the behavior of the actuator more robust. On the actuator, for example, other components such as adapter elements, tools, grippers or the like, which may have a considerable mass, are arranged. During operation of the actuator, consequently, the mass of these components must also be accelerated and decelerated without overloading or damaging the actuator.

It is also advantageous if the deceleration characteristic of the mechanical damper and / or the stroke of the mechanical damper is adjustable as a function of the switching on and off of the fluid pressure. Depending on the admission of the respective chamber with compressed air during the braking phase, other forces acting on the mechanical damper forces may result. The deceleration characteristic of the mechanical damper and / or the stroke of the mechanical damper can then in particular be adjusted manually or electrically as a function of these forces so that optimum mechanical braking can be achieved.

According to the invention it can be provided that the switching on and off of the fluid pressure takes place in such a way that in the mechanical braking phase either the sliding chamber is vented and the braking chamber ventilated or the sliding chamber and the braking chamber are vented. In the event that in the mechanical braking phase, the braking chamber is also ventilated, braking can not only be done exclusively on the mechanical damper, but also on the pressurization, so ventilate, the braking chamber.

Furthermore, it is conceivable that the switching on and off of the fluid pressure takes place in such a way that adjoining the mechanical braking phase is a pressure phase in which the sliding chamber is ventilated and the braking chamber is vented. By venting the sliding chamber can then be ensured a safe persistence of the actuator in the end position. In particular, it can be prevented that a kickback effect arises, which causes an unintended operation of the actuator from the end position in the opposite direction when reaching the end position.

The switching on and off of the fluid pressure can be such that the pressing phase is initiated before or with reaching the end position of the actuator. An early initiation of the pressure phase can result in that it is reliably prevented that the actuator, and in particular a mass arranged on the actuator, unintentionally leaves the end position after it has been reached.

It has also been found to be advantageous if the switching on and off of the fluid pressure takes place in such a way that a transitional phase is provided between the acceleration phase and the braking phase in which the sliding chamber is ventilated and the braking chamber is vented or in which the sliding chamber is vented and the braking chamber be ventilated. In the transition phase, for example, the speed of the actuator can be kept constant or largely constant.

The initiation of the respective movement phase can be carried out in particular as a function of a distance traveled by the actuator. A traveled path is also understood to mean a covered tilt angle if the actuator is a pivot unit. It is also conceivable that the respective movement phase is time-dependent. The individual movement phases are then assigned different durations.

Advantageously, to turn on and off the fluid pressure valves, and in particular controllable solenoid valves use.

The invention is also achieved by an actuator, in particular a pivoting or linear unit, with at least one piston, with two bounded by at least one piston chambers, and with an actuator which is movable in different movement phases depending on the distance traveled by the piston, wherein the chambers are independently ventilated or vented by switching fluid pressure on and off, and wherein a mechanical damper is provided. The actuator is also designed and set up to operate the method according to the invention.

The actuator may have a double-sided pressurizable piston, which limits the two chambers. It is also conceivable that the actuator has two pistons, the pistons then each defining at least one pressurizable chamber. The two pistons can then be synchronously coupled in motion via suitable components and drive the actuator, which can be designed as a linearly displaceable actuator or as a rotary actuator.

The actuator may also have a displacement sensor with which the path traveled by the actuator is detectable. In the case that the actuator is a rotary member, the distance traveled means the angle of rotation.

It is particularly advantageous if the actuator has its own control electronics, which is provided in particular within the housing of the actuator, and in the operation of the actuator, the valves, which are also preferably provided in the housing of the actuator, depending on the way detected by the displacement sensor or the Time is on. As a result, an actuator is provided in which all the essential components are included.

In this case, the deceleration characteristic of the mechanical damper is adjustable, the control electronics adjusted during operation of the actuator, the deceleration characteristic as a function of the control of the valves. This can be done an optimal tuning of the fluidic braking phase and the mechanical braking phase.

The control electronics as such can be designed so that they communicate with a higher-level control unit or machine control during operation of the actuator. The communication can be wired, for example via a bus system. The communication can also be wireless, for example via radio systems.

Furthermore, it may be advantageous if the deceleration characteristic of the mechanical damper is adjustable. It has turned out to be particularly advantageous if the deceleration characteristic of the mechanical damper can be adjusted via the control electronics inside the actuator. This has the advantage that depending on a switching on and off of the fluid pressure and the damping rate of the damper can be adjusted and adjusted accordingly.

The valves can be designed in particular as controllable solenoid valves. 3/2 Travel solenoid valves have proven to be advantageous here. The solenoid valves are controlled in particular by the actuator's own control electronics.

Further details and advantageous embodiments of the invention will become apparent from the following description, with reference to which an embodiment of the invention is described and explained in detail.

• 1 einen erfindungsgemäßen Aktuator in schematischer Darstellung.

Show it:

• 1 an actuator according to the invention in a schematic representation.

In the 1 is an actuator in the form of a swivel unit 10 shown. The swivel unit 10 includes two pistons 12 each having a pressurizable chamber 14 . 16 limit. The two pistons 12 are with an actuator 18 , which is designed here as a turntable, for example, coupled in motion via rack sections.

The chambers 14 . 16 each have their own 3/2-way solenoid valve 20, 22 with a compressed air line 24 connectable. In the switching position in which the compressed air line 24 the respective chamber 14 . 16 pressurized, the chamber becomes 14 . 16 consequently ventilated. In the position in which the respective solenoid valve 20 . 22 the respective chamber 14 . 16 depressurized, is the respective chamber 14 . 16 vented.

As is apparent from the schematic representation according to 1 shows, includes the pivot unit 10 a control electronics 26 which the two solenoid valves 20 . 22 independently of each other. As an input, the control electronics 26 a displacement measurement signal 28 on which the respective position of the actuator 18 detected and the control electronics 26 telling.

On the pressurizable chambers 14 . 16 opposite sides of the pistons 12 is a mechanical damper 30 intended. Preferably, the spring characteristic of the mechanical damper 30 via the control electronics 26 be adjusted.

The control electronics 26 can, for example, via a bus system with a higher-level control unit 32 be connected. The control unit 32 can, for example, for driving a handling system whose component is the pivoting unit 10 be provided. The higher-level control unit 32 turn, in turn, with a higher-level machine control 34 be connected. The swivel unit 33 can, however, also directly with the higher-level machine control 34 communicate.

During operation of the swivel unit 10 controls the control electronics 26 the valves 20 . 22 such that the actuator 18 can be moved in different phases of movement.

In an acceleration phase of the actuator 18 the sliding chamber, starting from the one in the 1 shown position the chamber 16 , ventilated and the braking chamber 14 vented, leaving the actuator 18 in the direction of the arrow 36 is accelerated.

The acceleration phase can be followed by a transitional phase in which the sliding chamber 16 and the braking chamber 14 be vented.

During operation, this braking phase is followed by a braking phase, which is in two parts. First, there is a fluidic braking phase in which the sliding chamber 16 vented and the braking chamber 14 is ventilated. Because of in the ventilated chamber 14 increasing pressure causes a delay of the piston 12 and thus the rotational movement of the actuator 18 , This fluidic braking phase is followed by a mechanical braking phase in which the respective piston 12 against the respective mechanical damper 30 moves. The mechanical damper 30 is thereby compressed and the movement of the piston and thus of the actuator 18 delayed until the pistons 12 , or the actuator 18 to reach their final position. When reaching the end position, or shortly before, a pressing phase takes place. In the Andrückphase is the sliding chamber 16 ventilated again and the braking chamber 14 vented so that a defined end position can be maintained. The fluidic combustion phase may also overlap with the mechanical braking phase; ie first, the fluidic braking phase is initiated. Subsequently, the mechanical braking phase is initiated during the fluidic braking phase. Finally, the fluidic braking phase is terminated, and the mechanical braking phase ultimately acts until the actuator 18 has reached the final position.

The fluidic braking phase and the mechanical braking phase are advantageously coordinated so that a bumpless delay can be ensured. For tuning and adjustment of the mechanical braking phase is in accordance 1 provided that the control electronics 26 the spring characteristic, and thus the deceleration rate of the mechanical damper 30 can adjust.

Overall, with the swivel unit shown 10 optimal acceleration and deceleration of the actuator 18 can be achieved, even with changing, on the actuator 18 provided masses.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1396642 A1 [0002]
• DE 102016107407 A1 [0003]

Claims (15)

Method for controlling a fluidically actuated actuator (10), wherein the actuator (10) has at least one piston (12), at least two chambers (14, 16) bounding the at least one piston (12) and an actuator (18) being provided wherein the actuator (18) is movable in different phases of movement in response to the travel of the piston (12), the chambers (14, 16) being independently ventable or ventable by switching fluid pressure on and off, and wherein in an acceleration phase characterized in that the braking phase comprises a fluidic braking phase and a mechanical braking phase, the switching on and off of the fluid pressure in the fluidic braking phase is such that the sliding chamber (14, 16) is vented and the braking chamber (16, 14) is vented, and that after Einleitun g the fluidic braking phase, a mechanical braking phase takes place in which a deceleration of the actuator (18) by means of a mechanical damper (30). Method according to Claim 1 , characterized in that the switching on and off of the fluid pressure is such that in the mechanical braking phase either venting the sliding chamber and the braking chamber are ventilated or the sliding chamber and the braking chamber are vented. Method according to Claim 1 or 2 , characterized in that the deceleration characteristic of the mechanical damper (30) and / or the stroke of the mechanical damper (30) is adjustable in dependence on the switching on and off of the fluid pressure Method according to Claim 1 . 2 or 3 , characterized in that the switching on and off of the fluid pressure takes place in such a way that adjoins the mechanical braking phase, a Andrückphase in which the sliding chamber ventilated and the braking chamber is vented. Method according to Claim 4 , characterized in that the switching on and off of the fluid pressure takes place in such a way that the pressing phase is initiated before or with reaching the end position of the actuator (18). Method according to one of the preceding claims, characterized in that the switching on and off of the fluid pressure is such that between the acceleration phase and the braking phase, a transitional phase is provided in which the sliding chamber vented and venting chamber vented or vented in the sliding chamber and the braking chamber to be vented. Method according to one of the preceding claims, characterized in that the initiation of the respective movement phase takes place as a function of a distance traveled and / or time-dependent. Method according to one of the preceding claims, characterized in that for switching on and off of the fluid pressure valves (20, 22) are used. Actuator, in particular pivoting or linear unit (10), with at least one piston (12), wherein the at least one piston (12) delimits at least two chambers (14, 16), with an actuator (18) which depends on the distance covered the piston (12) or the time in different movement phases is movable, wherein the chambers (14, 16) independently of each other by switching on and off of a fluid pressure ventilated or vented, and with a mechanical damper (30) for braking the actuator (30) before reaching an end position, wherein the actuator (10) is arranged so that it performs the method according to any one of the preceding claims in operation. Actuator (10) to Claim 9 , characterized in that the actuator (10) has a double-acting piston, which limits the two chambers or the actuator comprises two pistons (12), each defining at least one loadable chamber (14, 16). Actuator (10) to Claim 9 or 10 , characterized in that the actuator (10) has a displacement sensor (28) with which the distance covered by the actuator (18) is detectable. Actuator (10) to Claim 8 . 9 or 10 , characterized in that the actuator (10) has its own control electronics (26) which controls the valves (20) as a function of the path sensor (28) detected during operation of the actuator (10). Actuator (10) to Claim 12 , characterized in that the deceleration characteristic of the mechanical damper (30) is adjustable. Actuator (10) to Claim 12 and 13 , characterized in that the control electronics (28) during operation of the actuator (10), the delay characteristic in response to the control of the valves (20, 22) adjusted. Actuator (10) to Claim 12 . 13 or 14 , characterized in that the control electronics (26) designed such that it communicates with a higher-level control unit (32) or machine control (34) during operation of the actuator (10).

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