WO2009093901A1

WO2009093901A1 - Hydraulic manipulator joystick

Info

Publication number: WO2009093901A1
Application number: PCT/NL2009/050029
Authority: WO
Inventors: Bernhard Theodoor Sikkens
Original assignee: Paccus Interfaces B.V.
Priority date: 2008-01-25
Filing date: 2009-01-23
Publication date: 2009-07-30
Also published as: NL2001217C2

Abstract

A hydraulic manipulator (1), comprising a handle (3) which is movable in at least one plane, a first pressure element (2) connected to said handle, anα; a second pressure element (5). The pressure elements (2, 5) are movable relative to each other and enclose a space (6) to be filled with a pressure medium, the volume of which space is influenced by movement of the handle. The handle (3) is fixedly connected to the first pressure element (2). The advantage of this is that there is a direct connection between movement of the handle on the one hand and movement of the first pressure element with the resulting change in the volume of said space (6) on the other hand. In this way, a small amount of play and a high degree of precision of micro manipulations that can be realised therewith are ensured.

Description

HYDRAULIC MANIPULATOR JOYSTICK

The present invention relates to a hydraulic manipulator, comprising a first pressure element to be rigidly connected to a handle that is movable in at least one plane, and a second pressure element, which pressure elements are movable relative to each other and which enclose a space to be filled with a pressure medium, the volume of which space is influenced by movement of the handle.

The present invention further relates to a hydraulic system provided with such a manipulator.

Such manipulators, which are used as operating devices, control levers or joysticks in a professional or non-professional control system, for example for vehicles, tools, robots, simulators, machines, remote control units, games and the like, are generally known. The known manipulators have a handle, which is generally manually movable in two opposite directions along at least one line, to which handle a piston is connected. The piston functions as a first pressure element and is capable of translating movement within a second pressure element, which functions as a cylinder. Said piston and said cylinder, which are movable relative to each other, enclose a space filled with a pressure medium, wherein the volume of said space and the required pressure force are influenced upon forward and backward movement of the handle. In the case of hydraulic manipulators, the connection between the handle and the first pressure element, or the piston, is realised by means of intermediate pipes or a linkage, and in the case of electrical manipulators said connection is realised by- means of electromechanical elements and electric lines, which carry the movement or displacement signal from the handle to the pressure elements remote from the handle.

Such a manipulator is known from US 2002/0,113,771; see for example figures 4a ff. thereof.

The known solution leads to a specially scattered, indirect and not very precise transmission of such a displacement signal. As a result, manipulations in the form of displacements and movements that require a high degree of precision for specific applications are not possible. A drawback of the known manipulators is furthermore the fact that they take up a great deal of space.

The object of the present invention is to provide an improved, compact, low-play manipulator, which exhibits a higher degree of precision and which has a wider field of application.

In order to accomplish that object, the manipulator according to the invention is characterised in that the two pressure elements are pivotally movable relative to each other.

The advantage of the fact that the handle with the first and the second pressure element is pivotally movable is that, in particular in the case of small movements of the handle and of the first pressure element that is fixedly connected thereto, which movements can be manually controlled with a high degree of accuracy on account of the pivoting movement, there is a direct connection between said displacement and the spatial volume and the change in the medium pressure therein. This direct connection guarantees a high degree of accuracy and precision of the manipulator according to the invention in transmitting movement of the user's hand to the manipulator or, conversely, in transmitting forces from the manipulator to the user's hand, in which case the manipulator operates as an actuator.

Especially manipulators that require fine or small movements, for example manipulators for use in performing surgery, for example on delicate organs, can now be advantageously realised with a higher degree of precision. This makes it possible to perform surgery with a higher degree of accuracy than is possible with manually performed surgery. Such manipulators are also well suitable for use in the field of fine technology, or micro technology, and offer the user a realistic feel and touch. Because the advantageous effects of the movements and forces realised by means of the manipulator according to the invention can furthermore be electronically enhanced or diminished in proportion thereto, an even wider range of new applications becomes available.

An additional advantage is the fact that by changing the pressure and effecting pressure variations in the pressure medium that fills the space, a very realistic force and a corresponding sensation can be transmitted to the operator's hand. Said force can then be brought into conformity as regards the sensation experienced with the actual force that is experienced by, for example, a manipulator arm or a tool from the environment on which it is acting. Furthermore, vibrations can be transmitted back to the operator's hand as feedback signals, for example in proportion to the actual force variations being experienced.

One embodiment of the manipulator according to the invention is characterised in that the second pressure element has an at least partially cup-shaped cross-section in a plane perpendicular to a pivot axis between the two pressure elements .

As a result of the combination of the somewhat cup- shaped space between the two pressure elements and the pivoting movement transversely to the pivot axis described therein by the first pressure element, the movements made by the user's hand and the handle will be quite similar to the corresponding pivoting movement described by the first pressure element in this embodiment of the manipulator according to the invention. The manipulator, which is of compact construction, takes up little space at the location where it is mounted.

Another mechanically stable and symmetrical embodiment of the manipulator according to the invention is characterised in that the first pressure element extends over opposite sides of the handle via two pressure wings, and is arranged for carrying out a tilting movement within said space upon movement of the handle. Further embodiments defined in the other dependent claims relate to the stacked variant that is commonly used in practice, in which a functionally equivalent assembly of third and fourth pressure elements with a further space enclosed thereby is used for transmitting movement and forces in the other direction.

The manipulator according to the present invention will now be explained in more detail with reference to the appended drawing. In the drawing:

Figure 1 shows an exploded view of the manipulator according to the invention; and

Figures 2A and 2B show different possible positions of parts of a handle that are pivotable relative to each other for possible pivot-mounting to the handle of the manipulator shown in figure 1.

Figure 1 shows a preferred embodiment of a hydraulic joystick or manipulator 1. The manipulator 1 comprises a first pressure element 2, of symmetrical configuration in this embodiment. The pressure element 2 is rigidly connected to a handle 3 (schematically shown) , which is movable in at least one plane. Said at least one plane is oriented perpendicular to a pivot axis 4. The illustrated pressure element is symmetrical because it has two sector- shaped pressure wings 2-1, 2-2 in this case. It would be possible to use only one pressure wing, but in a more spatially configured embodiment it would also be possible to use more than two pressure wings. The manipulator 1 comprises a second pressure element 5, which is hollow and which is provided with a substantially cup-shaped space 6, which is enclosed between the two pressure elements 2 and 5, which are movable relative to each other. The pressure element 2 provided with said one or more pressure wings 2- 1, 2-2 is pivotally movable about the axis 4 within the space 6, which is filled with a suitable pressure medium in use. Used in a common hydraulic system, the medium is under pressure because the space 6 is connected to a commonly known, generally electrically controlled hydraulic pump. In the illustrated embodiment comprising two radially extending pressure wings 2-1, 2-2, the space 6 is essentially divided into two separate parts, and in the case of a particular angular displacement of the handle 3 and the pressure element 2, which will make a tilting movement in that case, the volume increase in one sub- space, indicated at 6-1 here, will be proportional to the volume decrease in the other sub-space 6-2. The spaces 6,

6-1, 6-2 are in general provided with several generally known movement sensors, G-sensors and/or pressure sensors

(not shown) , which will be connected to a processing unit comprising a programmable processor and an associated memory for eventually generating a signal that comprises a measure of the movement of the handle 3 in the aforesaid plane. In motion feedback, which is known per se, a counter pressure is generated in the pressure medium in that the hydraulic pump is suitably controlled by the unit, in order that the operator of the handle can maintain a feel for the forces exerted on the environment by all kinds of apparatuses and instruments controlled by means of the manipulator I₁ which forces may be substantial or minimal, depending on the circumstances. Furthermore, rebound or impact caused by jerky or vibratory changes in the medium pressure may be transmitted to the operator, which is a matter of control by the unit which, in contrast to the actual configuration of the manipulator 1, will not be discussed in detail herein. As already discussed in the foregoing, the manipulator 1, which is in fact made up of two parts, can in practice be used as a control, regulate or operating device in a hydraulic system suitable for that purpose. If influencing in more than one dimension is desired, the degree of freedom of "the second dimension" is added in a very compact manner by the addition of only one further part, in a manner to be described hereinafter. The handle 3 is in that case also movable in another plane oriented substantially perpendicular to said one plane, viz. being pivotally movable about another pivot axis 7. A third pressure element 8, which also has one or more radially extending sector-shaped pressure wings 8-1, 8-2, is disposed on either side of the axis 7. The second pressure element 6, which has a concave upper side, has a convex bottom side, which fits in a correspondingly shaped support, which forms the fourth pressure element 9. The third and the fourth pressure elements 8, 9 are pivotally movable about the axis 7 relative to each other, and enclose a further space 10 to be filled with a pressure medium. Upon movement of the handle 3 in the other plane about the axis 7, the first and the second pressure elements 2 and 5 will move jointly, but not relative to each other, when the axes 4 and 7 are oriented perpendicular to each other. The aforesaid movements in the two planes will take place independently of each other in that case . Since the second pressure element 5 and the third pressure element 8 form one and the same part of the manipulator 1 in the illustrated embodiment, a very compact - multiple - manipulator 1 being movable in several planes and directions is obtained.

The principles of that which has been explained in the foregoing concerning the single manipulator 1, inter alia with regard to the construction, movement and hydraulic operation of the first and the second pressure element 2, 5, also apply to the third and the fourth pressure element 8, 9 of the multiple manipulator 1, which are turned through 90° with respect thereto.

The multiple manipulator 1 that is shown herein is assembled from only three main parts, which can be produced in a simple manner by magnesium injection moulding, whilst the hydraulic seal between the part thereof, which are movable relative to each other, need not comprise any gaskets or sealing rings, and the play therebetween may even be about 0.1 mm. The reason for this is that the first pressure element 2 and the second pressure element 5, as well as the third pressure element 8 and the fourth pressure element 9, can move relative to each other, being supported on pressure medium leaking from the respective spaces 6 and 10. The hydraulic pump and the processor- controlled damping valves mounted in the respective hydraulic lines to the spaces 6, 10, maintain a specific pressure in, between and from the sub-spaces and spaces 6, 10, the amount of leakage being acceptable, as a result of which the operator will experience a corresponding force or change in force. The three parts 2, 5/8 and 9 shown in figure 1 can be placed in a cistern (not shown) into which the pressure medium, viz. the oil, which has a low pressure at that stage, can flow back. Common and inexpensive hydraulic seals will suffice for subsequently preventing leakage of oil under a low pressure from said cistern. The spaces 6, 10, in which the medium pressure is relatively high, are in that case surrounded by medium in the cistern, in which the pressure is low.

Figures 2A and 2B show to of many possible rotational positions of parts 12-1, 12-2, 12-3 of the handle 13, which are interconnected by means of pivots 11-1, 11-2, 11-3. The part 12-3 forms the actual handle, which is gripped by the operator and which can be turned to the position desired by said operator. The handle 13 is provided with angle (bearing) sensors connected to the aforesaid processing unit, which are provided at the location of the pivots 11- 1, 11-2, 11-3. The angle sensors transmit the manually adjusted angle positions or the changes of angle derived therefrom to, for example, a manipulator element such as an excavating tool, by means of which the soil is dug off or turned over. The handle 13 may be combined with the manipulator shown in figure 1, although this is not necessary. In the combined configuration, the angle (bearing) sensor hinge 11-3 is mounted, rotatably or fixedly, if desired, to the handle 3 of the manipulator 1 of figure 1. As a result, a multitude of degrees of freedom are added to the degrees of freedom already provided by the manipulator 1.

Claims

1. A hydraulic manipulator, comprising:

- a first pressure element to be rigidly connected to a handle that is movable in at least one plane, and

- a second pressure element, which pressure elements are movable relative to each other and which enclose a space to be filled with a pressure medium, the volume of which space is influenced by movement of the handle, characterised in that the two pressure elements are pivotally movable relative to each other.

2. A manipulator according to claim 1, characterised in that the first pressure element is provided with one or more sector-shaped pressure wings.

3. A manipulator according to claim 1 or 2 , characterised in that the second pressure element has an at least partially cup-shaped cross-section in a plane perpendicular to a pivot axis between the two pressure elements .

4. A manipulator according to any one of claims 1-3, characterised in that the first pressure element forms a radially extending boundary of said space.

5. A manipulator according to claim 4, characterised in that the first pressure element extends over opposite sides of the handle via two pressure wings and is arranged for carrying out a tilting movement within said space upon movement of the handle .

6. A manipulator according to any one of claims 1-5, characterised in that the handle is also movable in another plane oriented substantially perpendicular to said one plane .

7. A manipulator according to claim 6, characterised in that the manipulator is designed so that when the handle moves in said other plane, the first and the second pressure element will move along as one whole in said other plane.

8. A manipulator according to claim 6 or 7 , characterised in that the manipulator further comprises:

- a third pressure element to be rigidly connected to the handle, and

- a fourth pressure element, which third and which fourth pressure element are movable relative to each other and which enclose a space to be filled with a pressure medium, the volume of which space is influenced by movement of the handle in said other plane.

9. A manipulator according to claim 8, characterised in that said third pressure element is provided with one or more sector-shaped pressure wings.

10. A manipulator according to claim 8 or 9 , characterised in that the second and the third pressure element form the same part of the manipulator.

11. A manipulator according to any one of claims 1-

10, characterised in that the first and the second pressure element and the third and the fourth pressure element can each move relative to each other in a way wherein pressure medium is leaking from the respective two spaces.

12. A manipulator according to any one of claims 1- 11, characterised in that the manipulator is provided with a grip to be mounted to the handle, which grip is made up of parts fitted with angle sensors, which parts can pivot relative to each other.

13. A method wherein a manipulator according to any one of claims 1-12, which forms part of a hydraulic system whose at least one space filled with a hydraulic pressure medium is connected to a pump, is operated for controlling - possibly with sensor-controlled motion feedback - a vessel, aircraft, vehicle, instrument, machine, arm, tool, gripper or the like, or, conversely, is operated to act as an actuator for exerting forces on the handle resulting from pressure variations caused by external movement, which forces are transmitted to the pressure medium in said at least one space via the pressure elements.