GB2264753A

GB2264753A - Remote control system

Info

Publication number: GB2264753A
Application number: GB9304165A
Authority: GB
Inventors: Robert Hollow
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-03-03
Filing date: 1993-03-02
Publication date: 1993-09-08
Also published as: GB9304165D0; GB9204574D0

Abstract

A remote control system comprises a double-ended hydraulic piston 15 at the master station 10, coupled by a pair of hydraulic lines 18, 19 to a matching cylinder 30 at the slave station 20, with the power for driving the slave cylinder being derived directly from the operating force applied to the master cylinder. A combined bypass and pressure adjustment device 20 is located at the master station, the bypass function allowing the system to be initialized and the pressure adjustment function allowing any play or slackness in the system to be removed. Flow control valves 21, 22 are also included in the hydraulic lines. Movement of the rod 11 causes matching movement of rod 26. It may be desirable to use a double pair of cylinders instead of a single pair; and two degrees of freedom can be provided by using two pairs (or double pairs) of cylinders. <IMAGE>

Description

Remote Control System The present invention relates to remote control systerrJs, and more particut 1 rly to systerns for controlling the position of a device such as a camera.

A great variety of remote control techniques are known, such as mechanical couplings of various types, hydraulic couplings, pneurnatic couplings, electrical couplings, and electrical and electronic control systems. The present invention i@ concerned with remote control systems in which the distance between the con trol (roaster) station and the contrc)lled (slave) station is typically in the region of l - 10 m, the forces to be exerted at the slave station sre typically in the region of 10 - lOO N (ie to move bodies with masses typically in the region of I - tO kg by direct rnallual control) or in thet vicinity, and there can be a direct connection between the roaster and slave stations.

The present systern uses a double-énded hydraulic piston at the master station, coupled by a pelir of hydraulic lines to a matching cylinder at the slave station, with the power for driving the slave cylinder being derived directly from the operating force Applied to the master cylinder. (The hydraulic fluid is conveniently an oil such as a light oil or a conventional hydraulic oil.) A rnajor feature of the present system is the provision of a bypass device together with a pressure adjustment device, preferably both located at the master station the bypass device allowing the system to be initialized and the pressure adjust- anent device allowing any play or slackness in the system to be moved. One or snore flow control valves are alsc) preferably included.

In its simplest form, the present system includes a single pair of cylinders (one master and one slave), giving a single degree of freedorn. However, it may be desirable to use a double pair of cylinders instead of a single pair. Further, two degrees of freedom can be provided by using two pairs (or double pairs) of cylinders.

Further significant features of the invention will become apparent from the following detailed description of various control systems embodying the inven tion, given by way of example and with reference to the drawings, in which: Fig. 1 shows a system using a single pair of cylinders; Fig. 2 is a snore detailed sectional view of part of the Fig. 1 system; Fig. 3 shows a second system using a single pair of cylinders; and Fig. 4 shows a third system using a double pair of cylinders.

Fig. 1 shows a remote control system comprising a master station 10 and a slave station 25. The master station has a control lever 11, mounted on a base plate 12 by means of a ball joint 13, the movernent of which is to control the movement of a corresponding lever at the slave station. A double-ended hydraulic cylinder 15 is mounted by ball joints 16 and 17 between the base plate 12 and an arm 14 projecting from the lever 11. The two ends of the cylinder 15 are connected, through a bypass and adjustment device 20, to a pair of flexible hydraulic lines 18 and 19.

The slave station 25 has a lever 26, rnQunted on a base 27 by means of a ,aLl joint 28, the position of which is controlled to match that of the control lever 11 of the master station. A double-ended hydraulic cylinder 30 is mounted by ball joints 31 and 32 between the base plate 27 and an arm 29 projecting from the lever 26. The two ends of the cylinder 30 are connected to Ihe flexible hydraulic lines 18 and 19.

If the lever 11 is moved say to the right, the piston in the cylinder 15 will be moved downward. This will produce a flow of hydraulic fluid out through line 19 arid back in through line 18. The flow through line 19 passes into the bottom end of the cylinder 30 and the flow through liqe 18 passes out of the top end of that cylinder, so causing the piston in that cylinder to move upward. This raises the ball joint 31 and so causes the lever 26 to move to the right. The master and slave stations have matching geometries, so the movement of the slave lever 26 duplicates that of the master lever 11.

The two cylinders 15 and 30 are shown as on opposite sides of the levers 11 and 26 Obviously they can be on the same sides if the lines 18 and 19 are crossed over between the master and slave stations.

A pair of flow control valves 21 and 22 are included in the lines 18 and 19 adjacent to the device 20. These may be used to isolate the slave station and so lock it in a desired position. They may also be used to limit the flow rate through the lines 18 and 19. This provides sorne degree of control over the maximum rate of movement and reduces possible jerkiness.

Fig. 2 shows diagrammstically the details of the cylinder 15 and the bypass and adjustment device 20. The cylinder 15 hds a piston 35 attached to a piston rod 36 which passes through a seal at one end of the cylinder, the piston 35 dividing the cylinder into two chambers 37 and 38. These are connected to the bypass and adjustment device 20 through pipes 39 and 40, the device 20 compri sing a body 45 having two through bores 46 and 47 providing, direct connections between the pipes 39 and 40 and the pipes 18 and 19 respectively, as shown.

The device 20 includes bypass means comprising a bore 48 providing a direct connection between the lines 18 and 19. This bore can be opened and closed by a valve 49 which is operated by a knob 50 and shaft 51, which engages with a screw thread in an end. cap 52 of the body 45 and is sealed to that body by a seal 53.

The hydraulic system can gradually lose its accuracy, for various reasons, with the position of the sl.ave lever becoming different from that of the master lever. The bypass means enables the system to be readily reset, since opening the valve 49 allows the two levers to be moved independently.For example, the master lever can be moved to an extreme position, the bypass means opened and the master lever moved back somewhat, the bypass valve closed and the master lever moved as far as it can be towards the extreme position again (so ensuring that the slave lever is at its extreme position), the bypass valve opened again and the master lever moved the rest of its travel to its extreme position (so that it matches the slave lever), and the bypass valve closed again.

The device 20 also includes adjustment means comprising a cylinder 55 cornmunicating with the bore 48. The cylinder 55 has a piston 56 which is operated by a knob 57 and shaft 58, which engages es with a screw thread in an end razz 59 of the body 45. These means serve two purposes. First, by removing the end cap 59 and piston 56, the system can be topped up with hydraulic fluid.

Second, the system may be liable to leakage, resulting in slight loss of fluid and/or the entry of small amounts of air, which will cause loss of accuracy.

By tur-ning the knob 57 to move the piston 56 down the cylinder 55, the pressure in the system can be readily raised to reduce the effects of fluid loss and air entry to any desired extent.

Although it would be possible to provide separate means for implementing the bypass, fluid topping up, and pressure adjustment functions, it is particu marly convenient to use a unitary device providing all these functions, and for this unitary device to be of a size broadly matching the master cylinder and mounted adjacent thereto. This results in a compact and economical construc tion, and makes all three of the functions just mentioned readily available to the operator at the master station. The flow control valves 21 and 22 can also, of course, be made integrally with the device 20 is desired.

The levers and cylinders are shown as using ball joints. The system as described so far allows movement with only a single degree of freedom, for which simple pivot joints are sufficient. However, a second set of cylinders (one master and one slave) can be provided at right angles to the set shown (ie as seen looking downwards along the levers 11 end 26), tcs provide two degrees of fr-*edorn, and for this, ball joints or their equivalent are required.

In this arrangement, 'the mechanical characteristics of the slave station in the two different degrees of freedom may be different. This will be reflected in different "feels" for the two degrees of freedom at the master station. The provision of flow control valves in this arrangement allows the transmission flow rates between the two pairs of cylinders to be set differently, and this can be used to compensate at least partially for the different characteristics of the two decrees of freedom.

Fig. 3 shows a second rernote control system, comprising a master station 65 and a slave station 75. The master station has 8 cylinder 66 having a rack 67 mounted on its piston rod, this rack engaging with a pinion wheel 68 mounted on an arm 69 attached to the other end of the cylinder. A bypass and adjustment device 70 is mounted adjacent to the cylinder 66, and flow control valves 71 and 72 are located adjacent to the device 70. The slave station has a cylinder 76 having a rack 77 mounted crn its piston rod, this race engaging with a pinion wheel 78 mounted on an arm 79 attached to the other end of the cylinder.The cylinders 66 and 76 are coupled together via the device 70 as shown.

This system causes the slave shaft (ie the shaft on which the pinion wheel 78 is mounted) to follow the master shaf-t (ie the shaft on which the pinion wheel 68 is mounted). It thus provides a single degree of rotational freedom, with the rotation of the pinion 78 following that of pinion 68. The device 70 is the seme as device 20 of the systems of Figs. 1 and 2, and the details of the operation are also the same.

Fig. 4 shows a third remote control system using a double pair of cylinders, one pair at a master station S5 and the other pair at a slave station 100.

At the master station, a shaft 86 is mounted in bearings 87 arid 88 carried on arms mounted on a base plate 89, on which a pair of cylinders 92 and 93 are also mounted. The shaft 86 has two cranked portions 90 and 91 at right angles to each other. as seer looking along the shaft. The piston rods of the two cylinders 92 and 93 are coupled by the two cranked portions 90 and 91 by res -,ective bearings. Bypass and adjustment devices 94 and 96 are mounted adjacent to the cylinders 92 and 93 respectively.

At the slave station 100, a shaft 101 is mounted in bearings 102 and 103 carried on arms mounted on a base plate 104, on which a pair of cylinders 107 and 108 are also mounted. The shaft 101 has two cranked portions 105 and 106 at right angles to each other as seen looking along the shaft. The piston rods of the two cylinders 107 and 108 are coupled by the two cranked portions 105 and 106 by respective bearings. The cylinders 107 and 108 are coupled to the cylinders 92 and 93 by the devices 94 and 95 as shown.

This system provides a single degree of rotational freedom, with the rotation of the shaft 101 following that of shaft 86, and with the two pairs of cylinders being in quadrature. This arrangement requires two pairs of cylinders, compared with the single pair of the Fig. 3 system, but it allows an unlimited nurnber of rotations of the shafts. The devices 94 and 95 are the same as device 20 of the systems of Figs. l and 2, and the details of the operation of each pair of cylinders dre also the same.

Flow control valves (not shown) may of course be included in this system.

It will be realized that by suitably modifying the layout of the various -umponents of the master station, the two devices 94 and 95 may be located adja cent to each other. They can then be constructed as a single combined structure, optionally including flow control valves as well. This will allow, for example, a single structure to be used for providing the fluid topping up and pressure adjustment functions for both pairs of cylinders.

It will of course be realized that the three systems described can be cornbined in various ways to give various combinations of differing types of move ments.

Claims

Claims

1 Remote control apparatus comprising a master station having a double-ended cylinder coupled by a pair of hydraulic lines to a matching cylinder at a slave station, with the power for driving the slave cylinder being derived directly frorn the operating force applied to the master cylinder.

2 Remote control apparatus according; to claim 1 including a bypass device, connected between the hydraulic lines, which allows the system to be initialized.

3 Remote control apparatus according to claim 2 wherein the bypass device is located at the master station.

4 Rernote control apparatus according to any previous clairn including a pressure adjustment device, connected to one of the hydraulic lines, which allows any plray or slackness in the system to be removed.

5 Remote control apparatus according to clairn 4 wherein the pressure adjust- rnent device is located at the master station.

15 Remote control apparatus according to claims 3 and 5 wherein the bypass device and the pressure adjustment device together comprise a cylinder having a pair of through radial passages forming parts of the hydraulic lines, and an axial passage therebetween including a valve providing the bypass function and 'having an extension to one end of the cylinder provided with a piston providing the pressure adjustment function.

7 Rernote control apparatus according to claim 6 wherein the valve is an axial needle valve.

8 Remote control apparatus according to any previous claim including, in at least one of the hydraulic lines, a flow control device which allows the responsiveness of the apparatus to be adjusted and the apparatus to be locked in position.

9 Rernote control apparatus according to claim 8 wherein the or each flow control device is located at the master station.

10 Remote control apparatus according to any previous claim wherein the master and slave stations each cornprise 8 pivoted rod having an arm coupled to a pivoted cylinder mounted adjacent and parallel to the shaft.

12 A remote control system comprising a pair of remote control apparatuses according to any previous claim arranged in quadrature and having a common control element at the master station and a common controlled element at the slave station.

13 Remote control apparatus according to any of claims 1 to 9 wherein the master and slave stations each comprise a shaft having a pinion engaging a rack coupled to the associated cylinder.

14 Any novel and inventive feature or combination of features specifically disclosed herein within the meaning of Article 4H of the International Convention (Paris Convention).