FI130255B

FI130255B - An arrangement and a method for a robot device

Info

Publication number: FI130255B
Application number: FI20185101A
Authority: FI
Inventors: Vesa Hirvonen; Ville Hirvonen
Original assignee: Masinova Oy
Priority date: 2018-02-06
Filing date: 2018-02-06
Publication date: 2023-05-12
Also published as: CN111936277A; FI20185101A1; WO2019155121A1; CN111936277B

Abstract

The invention relates to an arrangement and a method for increasing the stroke speed of a robot device by adjusting the stroke length in speed and by balancing the robot device. The problem of increasing a stroke speed is vibration that can make the stroke inaccurate and may break the robot device in question. In the present invention, the arrangement comprises a double crankshaft, flywheels in connection with the crankshafts, two motors for adjusting the a stroke length by adjusting the position of said crankshafts in relation to said flywheels, wherein one motor is for rotating the crankshafts and the other for the flywheels.

Description

AN ARRANGEMENT AND A METHOD FOR A ROBOT DEVICE

Technical field

Generally, the invention relates to an arrangement and a method for a robot device, and more particularly the invention relates to an arrangement and a method for ad- justing the stroke length during an operation speed and balancing the Z-axis of the robot device in high speed.

Background technology

Robot devices can be programmed to provide a stroke or a press in the Z-axis. How- ever, adjusting a stroke length may be difficult to perform. Usually, the robot device has to be stopped when adjusting the stroke length, which takes time.

Normally, a stroke in Z-axis is arranged sin such a way that the striking device exe- cutes a reciprocating movement. Unfortunately, this is known to wear motors and mechanics in a robot device, which may shorten the life cycle of the robot device or at least cause costs due to repairing or replacing the worn parts.

The stroke speed of robot devices may be difficult to increase, because vibrations caused by the weight of the striking ram increase, when trying to increase the stroke speed. The vibrations decrease the stroke accuracy and may break the robot device.

This problem has been trying to solve by adding weight to the device for balancing © the ram, but in many cases, these solutions lead to very heavy devices, which can also & require a lot of space. For example, in a clean room circumstances, there are a lack

S of space, so big and heavy robot devices are especially impractical to use there.

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= — 25 Summary of the invention

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< It is an objective of the present invention to implement such a solution, that the pre-

I viously mentioned drawbacks of the prior art could be diminished. In particular, the invention is implied to solve how to increase striking speed of a robot device.

The objective of the invention is met by the features disclosed in the independent patent claims.

An arrangement for increasing a striking speed of a robot device according to the present invention is characterized by the features of claim 1.

According to an embodiment of the present invention, the arrangement for increasing a striking speed of a robot device comprises a double crankshaft, flywheels in con- nection with said crankshafts, two motors for adjusting the a stroke length by adjust- ing the position of said crankshafts in relation to said flywheels, wherein one motor is for rotating said crankshafts and the other for said flywheels.

In this embodiment, the stroke speed may be increased by a solution, wherein the stroke length can be adjusted in an operation speed without a need to stop the robot device for a stroke length adjustment.

In an embodiment, the arrangement further comprises a counterweight for balancing said Z-axis, so that said counterweight is connected in one crankshaft and a movable weight of said Z-axis in the other crankshaft, and wherein a phase difference between said crankshafts is 180° degrees. In this embodiment, the stroke speed of a robot de- vice may be increased by a solution, wherein the vibration caused by the inertia of a movable mass is decreased by the counterweight.

In one embodiment, the mass of the counterweight is selected to be the same as the mass of the movable weight. This feature may further enable to minimize the vibra- tion and help to increase the stroke speed.

In one embodiment, the shape of the counterweight is cylindrical, so that its center of © gravity is arrangeable in the same vertical axis with the movable weight. In this way

N it may be able to minimize the sideway vibration caused by moving weights in high

S 25 speed.

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7 In another embodiment, at least one pulling spring is arranged in Z-axis for lighten = the weight of the movable weight and/or the counterweight. In this feature, the static

S weight of the robot device in Z-axis may be able to compensate. < In an embodiment, horizontal arms of the robot device comprise adjustable counter-

N 30 weights. This feature may enable to balance also the horizontal arms of the robot device in order to avoid or at least minimize the vibration caused by the movement of these arms.

A method for increasing a striking speed of a robot device according to the present invention is characterized by the features of claim 7.

According to an embodiment of the present invention, a method for increasing a strik- ing speed of a robot device comprising an arrangement according to the present in- vention comprises at least a step of adjusting a stroke length by adjusting the position of the crankshafts in relation to the flywheels.

In an embodiment, the method comprises further steps of arranging said counter- weight in connection with one crankshaft and a movable weight of said Z-axis in the other crankshaft and arranging a phase difference between said crankshafts to be 180° degrees.

Some preferable embodiments of the invention are described in the dependent claims.

Significant advantages can be achieved with the present invention when compared to prior art solutions. The arrangement according to the present invention with the dou- ble crankshaft may be used for fast linear movement. Comparing to reciprocating movement the linear rotating movement may eliminate or at least reduce motors and mechanics wearing of the stroke system in a robot device. In addition, acceleration and deceleration in both ends of the linear movement may be able to be optimized in relation to speed. In this way, it may be possible to increase the stroke speed of a robot device.

The stroke length of a robot device may be able to be adjusted in every round and in full speed by using the arrangement according to the present invention. This may enable faster operation and easy programming of a stroke length function. In addition, the stroke length is steplessly adjustable from zero to the maximum stroke length. = The arrangement according to the present invention may also enable the starting and

N 25 ending points of the stroke length.

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I and compactible, which can mean that a robot device having the arrangement in ques- = tion may be a lot faster than a common robot device, for example ten times faster

O achieving even a stroke speed of 360 stroke rpm/min. However, the robot device hav- < 30 ing the arrangement in guestion may not reguire a bigger space for itself, but it may > be able to fit in a space of an average robot device. The robot device having the ar- rangement in guestion may be able to use in various purposes and in various condi- tions, such as a clean room condition.

The expression “high speed” refers herein to a crankshaft speed, which can be 300 rpm/min or more.

The expression “a number of” refers herein to any positive integer starting from one (1), e.g. to one, two, or three.

The terms “a” and “an”, as used herein, are defined as one or more than one.

Short description of the drawings

Next, the invention is described in more detail with reference to the appended draw- ings, in which

Fig. 1 depicts a perspective view of the arrangement according to an embodiment of the present invention in a robot device,

Fig. 2a — depicts a perspective view of the arrangement according to an embodiment of the present invention in a robot device in a stroke down —position,

Fig. 2b — depicts a perspective view of the arrangement in Fig. 2a in a stroke middle or stroke length zero —position,

Fig. 2c depicts a perspective view of the arrangement in Fig. 2a in a stroke up — position,

Fig. 3a — depicts a front view of the double crankshaft and flywheels according to an embodiment of the present invention in a robot device in a stroke down —position, = 20 Fig.3b depicts a front view of the double crankshaft and flywheels in Fig. 3a in a

N stroke middle or stroke length zero —position,

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O Fig. 3c — depicts a front view of the double crankshaft and flywheels in Fig. 3a in a

I stroke up —position, a

S Fig.4a = depicts a perspective view of 3a,

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2 25 Fig.4b depicts a perspective view of 3b,

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Fig. 4c — depicts a perspective view of 3c,

Fig. 5a and 5b depict adjustable counterweights in other arms of a robot device,

Fig. 6 is a flowchart of a method according to an embodiment of the present in- vention.

Detailed description of the embodiments 5 In the Figures herein, unique features receive unique reference numerals, while fea- tures that are the same in more than one drawing receive the same reference numerals throughout. Further, certain terms of orientation may be used, such as "upper," "lower," "top," "bottom," "left," "right," "inside," "outside," "interior," "exterior," "in- ner," and "outer." These terms are generally for convenience of reference, and should be so understood unless a particular embodiment requires otherwise.

Fig. 1 depicts a perspective view of the arrangement according to an embodiment of the present invention in a robot device. The arrangement comprises two motors 102 and 104 for Z-axis of the robot device in question, a double crankshaft 106 and fly- wheels 108 in connection with the crankshafts 106. The motors 102 and 104 are for adjusting a stroke length by adjusting the position of the crankshafts 106 in relation to the flywheels 108 in such a way that one motor is for rotating the crankshafts 106 and the other for the flywheels 108, as will be described in more detail below.

In an embodiment, the arrangement further comprises a counterweight 110 for bal- ancing said Z-axis. The movable weight 114 in Z-axis comprises other components of the robot device in question, such as arm units for X and Y-axes and motor units for moving the arm units in question.

The counterweight 110 1s connected in one crankshaft and the movable weight 114 © in the other. The flywheels 108 are preferably arranged to be at the both ends of the

N crankshafts 106 and between them, as will be described in more detailed below.

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© 25 In an embodiment, the mass of the counterweight 110 is selected to be the same as 7 the weight of the movable weight 114. The shape of the counterweight 110 is advan- = tageously cylindrical, so that its center of gravity can be arranged in the same vertical

S axis with the movable weight.

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2 According to an embodiment, at least one pulling spring 112 is arranged in Z-axis for

N 30 lighten the weight of said movable weight. The person skilled in the art understands that the arrangement can comprise more than one pulling spring and the characteris- tics of the springs may differ. The pulling string is connected from its upper end to the upper part of the robot device, preferably above the counterweight, and from its lower part to the movable weight.

Fig. 2a depicts a front view of the arrangement according to an embodiment of the present invention in a robot device in a stroke down —position, Fig. 2b the arrange- mentin Fig. 2a in a stroke middle or stroke length zero —position, and Fig. 2c the arrangement in Fig. 2a in a stroke up —position.

As can be seen in Figs. 2a-2c, the counterweight 110 is connected in one crankshaft 106a and a movable weight in another crankshaft 106b. In one embodiment, the phase difference between the counterweight 110 and said movable weight 114 is 180* de- grees, so that when the movable weight is in the stroke down —position, the counter- weight is in the up-position, and vice versa.

Fig. 3a depicts a front view of the double crankshaft and flywheels according to an embodiment of the present invention in a robot device in the stroke down —position,

Fig. 3b the double crankshaft and flywheels in Fig. 3a in the stroke middle or stroke length zero —position, and Fig. 3c the double crankshaft and flywheels in Fig. 3a in the stroke up —position. Respectively, Figs. 4a-4c depict a perspective view of Figs. 3a-3c.

In one embodiment, a stroke length is adjusted by adjusting the position of the crank- shaft 106a, 106b in relation to the flywheel 108. According to this embodiment, the motors (not shown in Figs 3a-3c, 4a-4c) are arranged to rotate the flywheels 108 and crankshafts 106a, 106b independently, so that one motor rotates flywheels 108 and the other crankshafts 106a, 106b.

As can be seen in the Figs. 3a and 3c, as well as 4a and 4c, the position of the crank- = shafts 106a, 106b in in relation to the flywheels 108 is arranged to be in the outermost

N 25 position, which means the longest stroke. In other words, when crankshaft is pointing <Q straight down, the end of the flywheel to which is connected with the crankshaft is

S also pointing down, and when crankshaft is pointing straight up, the end of the fly-

E wheel in guestion is also pointing up.

O In the Figs. 3c and 4c can be seen the stroke length zero —position. In this position, < 30 the crankshafts 106a, 106b are rotated 180 degrees from the maximum stroke position > to be the innermost position between the flywheels. In this case, when the motors are rotating the flywheels and the crankshafts, the stroke length is zero.

The stroke lengths between the zero and maximum are continuously adjusted by ad- justing the angle between the flywheels and the crankshafts between zero and 180 degrees.

Fig. 5a and 5b depict adjustable counterweights 402 in other arms 404a, 404b of the robot device. Typically, the robot device comprises at least two arms connected to- gether for covering x-y axes. The arms are moved in relation to each other into dif- ferent positions. According to the present invention, counterweight 402 are arranged in the horizontal axis of the arms 404a, 404b for compensate the mass of the arm in relation to the working axis.

The counterweight 402 are arranged to be movable in the horizontal axis and, when the arms 404a, 404b are moved, the counterweight 402 are moved in a position, wherein the weights of the arms are in balance at the point of view of the working axis 406.

Fig. 6 1s a flowchart of a method according to an embodiment of the present invention.

IS At step 502, the counterweight is arranged in connection with one crankshaft and the movable weight in the other. At step 504, the crankshafts are arranged to have 180° phase difference, so that when the movable weight is moving down, the counter- weight is moving up, and vice versa.

Another embodiment comprises a step 506, wherein the stroke length of the robot device is adjusted by adjusting the position of the crankshaft in relation to the fly- wheels. This step is repeated when running a striking program with the robot device.

The scope of the invention is determined by the attached claims together with the eguivalents thereof. The skilled persons will again appreciate the fact that the explic- = itly disclosed embodiments were constructed for illustrative purposes only, and the

N 25 scope will cover further embodiments, embodiment combinations, manufacturing <Q processes, and equivalents that better suit each particular use case of the invention. 3 i > co

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Claims

1. An arrangement for increasing a striking speed of a robot device comprising: - a double crankshaft (106) comprising two crankshafts (106a, 106b) arranged to rotate around the same axis having a phase difference substantially 180° degrees, flywheels (108) in connection with the crankshafts (106) at one end of said flywheel for adjust- ing the a stroke length, - two motors (102, 104) , characterized in that one motor is for rotating said crankshafts (106) and the other for rotat- ing said flywheels (108) for adjusting the angle between the flywheels (108) and the crank- shafts (106) between substantially zero and 180 degrees in order to adjust said stoke length, wherein said zero angle is a maximum stroke length and said 180 degrees angle is a mini- mum stroke length.

2. An arrangement according to the claim 1, wherein said arrangement further compris- es a counterweight (110) for balancing the vertical axis of a robot device in guestion, so that said counterweight (110) is connected in one crankshaft (106a) and a movable weight (114) of a robot device in question in the other crankshaft (106b)..

3. An arrangement according to the claim 2, wherein the mass of said counterweight (110) corresponds the mass of the movable weight (114).

4. An arrangement according to any of claim 2-3, wherein the shape of said counter- weight (110) is cylindrical, so that its center of gravity is arrangeable in the same vertical axis with said movable weight (114). O QA a 5. An arrangement according to any preceding claim, wherein at least one pulling g spring (112) is arranged in Z-axis for lighten the weight of said movable weight (114). N

T 6. An arrangement according to any preceding claim, wherein the robot device in gues- E tion comprises at least one horizontal arm, which comprises at least one adjustable counter- S weight.

o 7. A method for increasing a striking speed of a robot device comprising an arrange- N ment according to any of claims 1-6, characterized in that, the method comprises at least following step:

- adjusting a stroke length by adjusting the position of said crankshafts in relation to said flywheels (106) by means of one motor of the arrangement.

8. A method for increasing a striking speed of a robot device comprising an arrange- ment according to any of claims 2-6, characterized in that, the method comprises at least following step: - adjusting a stroke length by adjusting the position of said crankshafts in relation to said flywheels (106) by means of one motor of the arrangement. - arranging said counterweight in connection with one crankshaft and a movable weight of a robot device in question in connection with the other crankshaft (502); - arranging a phase difference between said crankshafts to be 180° degrees (504). O QA O N O I N I = O LO 00 O N