GB2165207A

GB2165207A - Motion unit, especially for manipulators, industrial robots and prosthetic elements

Info

Publication number: GB2165207A
Application number: GB08425277A
Authority: GB
Inventors: Josef Kovar
Original assignee: Spofa Spojene Podniky Pro Zdravotnickou Vyrobu; Spofa Vereinigte Pharma Werke
Current assignee: Spofa Spojene Podniky Pro Zdravotnickou Vyrobu; Spofa Vereinigte Pharma Werke
Priority date: 1981-08-12
Filing date: 1984-10-05
Publication date: 1986-04-09
Also published as: GB8425277D0; GB2165207B

Abstract

It is an object of the invention to provide a lightweight, space saving, structurally simple and inexpensive motion unit which is particularly designed for manipulators, industrial robots and prosthetic elements and which comprises at least one rotational and/or translational kinematic pair composed of a positioning and an orienting member, a drive unit, and means for transmitting the motion from the drive unit to the orienting member of said kinematic pair. The motion transmitting means consist of at least two filaments having first and second ends, the former being fixed to a common rotary support and the latter being connected with the orienting member of the kinematic pair. <IMAGE>

Description

SPECIFICATION Motion unit, especially for manipulators, industrial robots and prosthetic elements The invention relates to a motion unit, especially for manipulators, industrial robots and prosthetic elements, comprising at least one rotational and/or translational kinematicbair composed of a positioning and an orienting member, further a drive unit, and means for transmitting the motion from the drive unit to the orienting member of said kinematic pair.

With hitherto known#conventional motion units there have been employed for transmitting motion from the drive unit to the orienting member of one or a plurality of kinematic pairs usual mechanical structural elements such as gear wheels, motion screws, tierods, cams, Bowden cables, or the like.

Disadvantages encountered with such motion units consist in a relatively high weight and claims laid on space, and, particularly with a plurality of kinematic pairs for obtaining more intricate movements, the structure thereof is complicated and therefore expensive.

To reduce the complexity of the motion transmitting means the motion units are provided with a plurality of drive units. However, the provision of such additional drive units is expensive. Also the use of a plurality of drive units in a limited space makes it impossible to apply them in a simple structural form.

With motion units wherein Bowden cables are employed for transmitting motion to the orienting members of the kinematic pairs, it is admittedly possible to reduce their weight and spatial claims but, on the other hand, to obtain relatively low output revolution rates, claims to be laid on the drive unit structure, rise, unless additional motion transmitting means are associated with the drive unit.

It is an object of the present invention to eliminate the drawbacks of prior art as hereinabove set forth and to provide a relatively lightweight space saving, structurally simple and inexpensive motion unit.

These advantages can be ascertained also with motion units co-operating with a plurality of kinematic pairs.

According to the present invention a motion unit includes motion transmitting means comprising at least two filaments having first ends and second ends, the first ends being fixedly attached to a common rotary support and the second ends being connected with the orienting member of the kinematic pair.

Preferably, the second ends of the filaments may be fixed to at least two orienting members of the kinematic pairs, either directly, or via a compensating element.

Preferably also the filaments may be led through guide means, such as eyelets or the like, which are fixedly attached to the orienting member of the kinematic pairs.

Preferably also, the positioning member of the kinematic pair may be secured to a resilient element.

The essential advantages of the motion unit of the invention are its structural simplicity, reduced weight, space economy and low costs.

Another advantage consists in the possibility of using a single or a minimum member of drive units which do not require specific transmitting means to reduce their output revolution rates.

Still another advantage of the motion unit of the invention is in the possibility of controllin#g a plural- ity of orienting members of the kinematic pairs, viz.

at least two of them, without it being necessary to increase the complexity of the motion transmitting means, or the number of elements thereof. Thus it is possible to attain an automatic guiding of the motion means as a complex, or only of the output kinematic pairs thereof, without it being necessary to employ position compensators.

A further advantage is that the motion unit enables the orienting members of the kinematic pairs to be activated one after the other in dependance upon the choice of internal resistances. The sequence and the magnitude of said internal resistances can be determined according to a programme, which makes it possible to generate a continuous motion of the unit in a limited space. With the motion unit according to the invention, itis possible to utilize immediatelythe moment of inertia of the drive unit for correcting the control power after a switch-off signal is given by a sensor, such as, for instance, in the process of feeding soft materials with welding jaws, punching dies, or the like.

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying schematic drawings wherein Figure 1 shows a motion unit having a plurality of rotational kinematic pairs; Figure 2 shows the motion unit illustrated in Figure 1 in another position; Figure 3 is a partial view of the motion unit comprising a rotational and a translational kinematic pair; Figure 4 shows a part of the motion unit with two motion transmitting means; Figures 5through 8 shows individual phases of motion of the motion unit having rotational kinematic pairs; Figures 9 and 10 show individual phases of motion of an alternative embodiment of the invention; Figures 11 and 12 show individual phases of motion of another alternative embodiment;; Figure 13 illustrates a part of the motion unit together with inbuiltcompensating means; and Figures 14 and 15 show each a part of the motion unit comprising an alternative kinematic pair embodiment, respectively.

Figures 1 and 2 show a motion unit having a plurality of rotational kinematic pairs consisting each of a positioning member 2 and an orienting member 3. The orienting member 3 of the preceding kinematic pair constitutes simultaneously the positioning member 2 of the next kinematic pair. The last kinematic pairs are composed of the positioning member 2' and two orienting members 3', 3". The motion unit comprises further a drive unit 1 which is secured in this embodiment to the positioning member 2 of the first kinematic pair. The rotor of said drive unit 1 forms a comon rotary support which is connected to first ends of the filaments 4. The filaments 4 of which there are at least two, constitute means for transmitting motion from the drive unit 1 to the individual kinematic pairs.The opposite or second ends of the filaments 4 are attached to the orienting members 3, 3' of the kinematic pair. In the embodiment comprising two filaments, the second end of one of the filaments 4 is fixed to the orienting member3' while the second end ofthe second filament is fixed to the orienting member 3". The filaments 4 can be led either directly from the drive unit 1 to the orienting members 3, 3', or, as shown in Figure 1, through guide means 5 fixedly attached to the orienting members of the kinematic pairs. The guide means 5 may consist of eyelets, rollers, or the like. The motion unit can be returned to its initial position by reversing means such as springs, weights or the like. Such means are not illustrated in the drawings.Alternatively, it is possible to use for this purpose an additional system of filaments attached to the drive unit so as to act in the opposite direction to that shown in the drawings.

The use of a translational kinematic pair is apparent from Figure 3 wherein the positioning member 12 is connected to the orienting member 13. In addition to the filaments 4 connected to the orienting members 3', 3", additional filaments 4' are secured to the guide means 5.

As shown in Figure 4, the positioning member 2 and the orienting member 3 form together a kinematic pair controlled by the filaments 4'. The orienting member 3 also serves as the positioning member for the following kinematic pairs, the orienting members 3', 3" of which are controlled by the filaments 4 via a compensating element 6.

Figures 5 through 8 show the motion unit in the individual movement phases thereof, wherein the individual kinematic pairs are activated one after the other in dependance upon the choice of internal resistances acting in opposition to the power of the drive unit 1. The second ends of the filaments 4 are fixedly attached to the guide means 5 of the orienting member of the last kinematic pair whereas the filaments 4 freely pass through the guide means 5 of the preceding kinematic pairs.

As shown in Figures 9 and 10, the second end of one of the filaments 4 is secured to the guide means 5 of the first kinematic pair while the secondary end of the second filament 4 is fixed via a symmetrizing member 7 to the guide means 5 of the next kinematic pair.

Figures 11 and 12 illustrate the positioning member 2 as being secured to a resilient element 9. The filaments 4 are attached to the guide means 5 of the orienting members 3', 3", one of the filaments 4 being connected with the orienting member 3" through a link 8. The connection between said link 8 and the guide means 5 does not require any filament 4to be used, and can be performed by any suitable flexible element. Individual members of a prosthetic device are constituted by individual kinematic pairs having, optionally, a variable rotation axis.

As can be seen in Figure 13, the orienting members 3', 3" are controlled by the filaments 4 through a compensating element 6.

An alternative embodiment of the kinematic pairs is shown in Figures 14 and 15, wherein the positioning member 2 is constituted by a frame, and the orienting member 3 by a gear wheel, or a rack.

Another kinematic pair is formed between a pair of gear wheels, or between a gear wheel and a rack.

In operation of the motion unit, some preferred embodiments of which have hereinbefore been described, each of the kinematic pairs is pulled by the filaments 4, the first ends of which are coupled with the rotor of an electric motor whereby the filaments are twisted together and consequently shortened. By shortening the length of the filaments 4the orienting members 3, 3', 3", 13 are caused to rotate, or shift with respect to the positioning members 2, 2', 12, respectively. In this way the motion unit is caused, firstly to change its position and, secondly, there is generated a functional movement with the final or output kinematic pairs serving, for example, as seizing jaws.If a plurality of systems of filaments 4, 4' is used, as shown in Figure 3, the functional movement of the last kinematic pair is generated by the action of the filaments 4, whereas changes in the position of said last kinematic pair are caused by movement of the preceding kinematic pairs, resulting from the action of the filaments 4'. As shown in Figure 4, the functional movement of the orienting members 3', 3" constituting the seizing jaws which are symmetrically movable, is attained by twisting the filaments 4 attached to the compensating element 6. The successive changes of the motion unit positions, as shown in Figures 5 through 8, depend upon internal resistances of the individual kinematic pairs which can be, optionally, adjusted according to a programme so that it is possible to provide an arbitrary successive activation thereof.

In the embodiments of Figures 9 and 10 as well as Figure 3, each of two orienting members 3 of the kinematic pair is controlled by one of at lest two filaments 4 which are twisted together. The symmetrizing member 7 serves to equalize the distance between the individual guide means 5 to which the filaments 4 are attached.

As schematically illustrated in Figures 11 and 12, the joining of the filaments 4 can be simplified by using links 8. By untwisting the second ends of the filaments 4 and by attaching them to different orienting members 3', 3" it is possible to raise the output of the motion unit and thus to provide the possibility of automatically adjusting the motion unit with respect to the object to be seized or gripped. A similar effect is attainable with the motion unit shown in Figure 13, wherein the filaments 4 control the orienting members 3', 3" through the compensating element 6.

The return of the motion unit into the initial position can be provided by a positive motion to be generated, for instance, by using additional twisting filaments acting in the opposite direction, by gravity due to the weight of motion unit, or by utilizing an accumulated energy of the activating motion bodies such as, for instance, by using springs, accumulators, or the like.

An essential feature of the present invention consists in that the first ends of the filaments are fixedly attached to a common rotary support which can be constituted, by way for example, by the rotor of a motor.

To soften the seizing grip, and particularly with the seizing elements formed by the last kinematic pairs, it is possible to employ resilient or elastic means such as springs, or the like. Such means are to be interposed preferably between the second end of the filament or filaments 4 and the orienting member of the kinematic pair, or the guide means secured to said orienting member.

Claims

1. A motion unit, especially for manipulators, industrial robots and prosthetic elements, comprising at least one rotational andior translational kinematic pair comprising a positioning and an orienting member, a drive unit, and means for transmitting the motion from the drive unit to the orienting member of said kinematic pair, wherein the motion transmitting means consist of at least two filaments having first ends and second ends, the first ends being fixedly attached to a common rotary support and the second ends being connected with the orienting member of the kinematic pair.

2. A motion unit as claimed in claim 1, wherein the second ends of the filaments are affixed to at least two orienting members of the kinematic pairs.

3. A motion unit as claimed in claim 2, wherein the second ends of the filaments are connected with the orienting members of the kinematic pairs via a compensating element.

4. A motion unit as claimed in claims 1 through 3, wherein the filaments are led through guide means fixedly attached to the orienting member of the kinematic pairs.

5. A motion unit as claimed in claims 1 through 4, wherein the positioning member of the kinematic pair is secured to a resilient element.