GB2261531A - Drive systems - Google Patents
Drive systems Download PDFInfo
- Publication number
- GB2261531A GB2261531A GB9124181A GB9124181A GB2261531A GB 2261531 A GB2261531 A GB 2261531A GB 9124181 A GB9124181 A GB 9124181A GB 9124181 A GB9124181 A GB 9124181A GB 2261531 A GB2261531 A GB 2261531A
- Authority
- GB
- United Kingdom
- Prior art keywords
- drive
- output shaft
- drive system
- motors
- drive motors
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
- G05B19/19—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
- G05B19/21—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path using an incremental digital measuring device
- G05B19/23—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path using an incremental digital measuring device for point-to-point control
- G05B19/231—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path using an incremental digital measuring device for point-to-point control the positional error is used to control continuously the servomotor according to its magnitude
- G05B19/237—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path using an incremental digital measuring device for point-to-point control the positional error is used to control continuously the servomotor according to its magnitude with a combination of feedback covered by G05B19/232 - G05B19/235
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/41—Servomotor, servo controller till figures
- G05B2219/41264—Driven by two motors
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/41—Servomotor, servo controller till figures
- G05B2219/41361—Differential
Abstract
A drive system for driving a single rotary output shaft 14 has two drive motors 11, 12. A differential transmission unit 13 combines the respective drives of the motors and transmits the resultant drive to the rotary output shaft. A control unit 15 controls the motors in response to an input signal representing the required angular velocity and/or angular position of the output shaft 14. Feedback of the output and motor shaft positions 16, 17, 18 may be provided. The motors may be hydraulic, electric or pneumatic and may be combined using different gear ratios to provide different weightings for their respective contributions to the speed of the output shaft 14. The motors may be driven in opposite directions to maintain the output shaft stationary. <IMAGE>
Description
DRIVE SYSTEMS
This invention relates to drive systems, and the invention relates particularly, though not exclusively, to drive systems for use in high speed, positioning applications.
A rotary motor, such as an hydraulic motor, is generally considered unsuitable for high speed positioning applications because of mechanical non-uniformities and stiction which make it difficult to control the drive shaft of the motor at low rotation speeds. Some improvement can be gained by using a high gear reduction; however, this has the undesirable effect of reducing the maximum operating speed of the motor. It is an object of the invention to provide a drive system which at least alleviates this problem.
According to the invention, there is provided a drive system for driving a rotary output shaft comprising, at least two drive motors, differential transmission means for combining the respective drives of said at least two drive motors and for transmitting the resultant drive to said rotary output shaft, and control means for controlling each of the drive motors in response to an input signal representing a required angular velocity and/or angular position of the rotary output shaft.
At least one of the motors may be an hydraulic motor, an electric motor or a pneumatic motor. The at least two drive motors need not necessarily be of the same type.
A drive system in accordance with the invention has at least two drive motors but, in effect, functions as a single, high performance actuator for the rotary output shaft, enabling the angular speed and/or position of the rotary output shaft to be controlled with a speed and precision not hitherto attainable using a single drive motor, such as an hydraulic motor.
In a preferred embodiment, the drive system has only two of said drive motors.
To improve the performance of the drive system, the control means may incorporate a feedback loop. To that end, the control means may be responsive to a feedback signal representing the actual velocity and/or angular position of the rotary output shaft. The feedback signal may be generated by a transducer arranged to monitor the angular velocity and/or angular position of the rotary output shaft.
Similarly, the control means may be responsive to feedback signals derived from the at least two drive motors, and such feedback signals may be generated by respective transducers arranged to monitor the angular velocities and/or angular positions of the drive shafts of the drive motors. The transducers may be optical encoder transducers.
In a preferred embodiment of the invention, the differential transmission means includes a gear arrangement for weighting the respective drives of the at least two drive motors in accordance with different gearing ratios.
In a particular application of the invention, the control means has the capability to generate control signals which cause the first and second drive motors to produce drive in opposite rotational senses, and by this means may maintain the rotary output shaft at a predetermined angular position.
A drive system according to the invention is now described, by way of example only, with reference to the accompanying drawing which gives a block schematic illustration of the drive system.
Referring to the drawing, the drive system 10 comprises two rotary drive motors 11,12 which could be hydraulic, electric or pneumatic motors, or a combination of these.
Each motor has a drive shaft 11',12' which is coupled to a differential transmission unit 13. The transmission unit 13 incorporates a gear arrangement which is effective to combine the drives of the two motors 11,12 in a predetermined manner and to transmit the resultant drive to a single rotary output shaft 14.
Both rotary drive motors 11,12 are controlled by a control unit 15 which receives an input signal (pro) representing a required angular velocity and/or angular position of the rotary output shaft 14.
The control unit 15 also receives a feedback signal (fl) representing the actual angular velocity and/or angular position (o ,8 ) of the rotary output shaft 14.
The feedback signal (fl) is generated by a transducer 16, such as an optical encoder transducer, disposed to monitor rotation of the rotary output shaft. The control unit 15 receives two further feedback signals (f2,f3) which are derived from the two rotary drive motors 11,12 and represent the angular velocity and/or angular position of their respective drive shafts 11',12'. Again, the feedback signals f2,f3 are generated by transducers, such as optical encoder transducers 17,18, arranged to monitor rotation of the drive shafts 11',12'.
The control unit 15 is programmed to process the input signal rO and the feedback signals f1, f2 and f3 whereby to generate two control signals, u1,u2 which are used to control the rotary drive motors 11,12 in accordance with the required angular velocity and/or angular position of the rotary output shaft 14, and in this way the drive shafts 11',12' are driven at respective angular velocities 1t2.
By coordinating the control of both rotary drive motors 11,12, and combining their respective drives in the differential transmission unit 13, the overall drive system functions as a single actuator for the rotary output shaft 14, having a performance exceeding that of either drive motor individually, enabling the rotary drive shaft 14 to be positioned with precision, and at high speed.
This can be accomplished by the drive system in a variety of different ways.
For example, the differential transmission unit 13 may be designed to weight the respective drives of the two rotary drive motors in accordance with different gearing ratios.
By this means, the rotary drive motor which is subjected to the higher gearing ratio will contribute a relatively low velocity component to the overall angular velocity o of the rotary drive shaft 14, enabling the shaft to be positioned with high accuracy, whereas the other rotary drive motor, which is subjected to the lower gearing ratio, will contribute a relatively high velocity component to the overall angular velocity, enabling the shaft to be positioned at high speed.
Thus, by co-ordinating the control of both rotary drive motors 11,12 complementary operating characteristics of each can be combined to achieve accurate, high speed positioning of the rotary output shaft.
In another mode of operation, the control signals u1,u2 cause the drive shafts 11',12' of the rotary drive motors 11,12 to rotate in opposite senses. In such circumstances, the differential transmission unit 13 generates a resultant drive which is the difference of individual input drives produced by the two motors 11,12.
In this way, the rotary output shaft 14 can be driven at a relatively low angular velocity, and thereby positioned accurately, even though the rotary motors 11,12 are both being driven at a much higher angular velocity and have relatively poor positioning capability. Similarly, when the individual input drives produced by the two rotary motors 11,12 are exactly the same (but are acting in opposite senses) the resultant angular velocity, generated by the differential transmission unit 13, will be zero, enabling the rotary output shaft 14 to be maintained at a desired angular position even though the rotary drive motors 11,12 are still being driven at high speed.
By controlling the two drive motors and combining their respective contributions, a drive system according to the present invention can provide a performance which exceeds that of either rotary drive motor individually.
Claims (13)
1. A drive system for driving a rotary output shaft comprising, at least two drive motors, differential transmission means for combining the respective drives of said at least two drive motors and for transmitting the resultant drive to said rotary output shaft, and control means for controlling each of the drive motors in response to an input signal representing a required angular velocity and/or angular position of the rotary output shaft.
2. A drive system as claimed in claim 1, wherein at least one of the drive motors is selected from the group consisting of an hydraulic motor, an electric motor and a pneumatic motor.
3. A drive system as claimed in claim 1 or claim 2, wherein the drive motors are of the same type.
4. A drive system as claimed in any one of claims 1 to 3, having two said drive motors.
5. A drive system as claimed in any one of claims 1 to 4, wherein the control means is responsive to a feedback signal representing the actual angular velocity and/or angular position of the rotary output shaft.
6. A drive system as claimed in claim 5, wherein said feedback signal is generated by a transducer arranged to monitor the angular velocity and/or angular position of the rotary output shaft.
7. A drive system as claimed in claim 6, wherein the transducer is an optical encoder transducer.
8. A drive system as claimed in any one of claims 1 to 7, wherein the control means is responsive to feedback signals derived from the drive motors.
9. A drive system as claimed in claim 8, wherein said feedback signals are generated by respective transducers arranged to monitor the angular velocities and/or angular positions of the drive shafts of the drive motors.
10. A drive system as claimed in claim 9, wherein said transducers are optical encoder transducers.
11. A drive system as claimed in any preceding claim, wherein the differential transmission means includes a gear arrangement for weighting the drives of the at least two drive motors in accordance with different gearing ratios.
12. A drive system as claimed in any preceding claim, comprising a first said drive motor and a second said drive motor wherein the control means generates control signals for causing the first and second drive motors to produce drive in opposite rotational senses whereby to maintain the output shaft at a predetermined angular position.
13. A drive system substantially as herein described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9124181A GB2261531A (en) | 1991-11-14 | 1991-11-14 | Drive systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9124181A GB2261531A (en) | 1991-11-14 | 1991-11-14 | Drive systems |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9124181D0 GB9124181D0 (en) | 1992-01-08 |
| GB2261531A true GB2261531A (en) | 1993-05-19 |
Family
ID=10704614
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9124181A Withdrawn GB2261531A (en) | 1991-11-14 | 1991-11-14 | Drive systems |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2261531A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2296789A (en) * | 1994-12-31 | 1996-07-10 | Teijin Seiki Co Ltd | Controller for reduction gear device |
| WO2008080957A1 (en) * | 2006-12-27 | 2008-07-10 | Lenze Automation Gmbh | Drive device comprising a plurality of drives and regulating system for this overall drive |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB516393A (en) * | 1938-06-25 | 1940-01-01 | Smith & Sons Ltd S | Improvements in or relating to electrical servomotor systems |
| GB830405A (en) * | 1955-02-09 | 1960-03-16 | Pratt & Whitney Co Inc | Positioning mechanism |
| GB1232586A (en) * | 1967-07-20 | 1971-05-19 | ||
| GB1544246A (en) * | 1975-05-26 | 1979-04-19 | Applic Mach Motrices | Regulating device |
| WO1983000204A1 (en) * | 1981-06-26 | 1983-01-20 | Rose, Stanley, E. | Spacial mechanism and method |
-
1991
- 1991-11-14 GB GB9124181A patent/GB2261531A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB516393A (en) * | 1938-06-25 | 1940-01-01 | Smith & Sons Ltd S | Improvements in or relating to electrical servomotor systems |
| GB830405A (en) * | 1955-02-09 | 1960-03-16 | Pratt & Whitney Co Inc | Positioning mechanism |
| GB1232586A (en) * | 1967-07-20 | 1971-05-19 | ||
| GB1544246A (en) * | 1975-05-26 | 1979-04-19 | Applic Mach Motrices | Regulating device |
| WO1983000204A1 (en) * | 1981-06-26 | 1983-01-20 | Rose, Stanley, E. | Spacial mechanism and method |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2296789A (en) * | 1994-12-31 | 1996-07-10 | Teijin Seiki Co Ltd | Controller for reduction gear device |
| US5672135A (en) * | 1994-12-31 | 1997-09-30 | Teijin Seiki Co., Ltd. | Controller for planetary differential type reduction gear device |
| GB2296789B (en) * | 1994-12-31 | 1999-05-05 | Teijin Seiki Co Ltd | Controller for reduction gear device |
| WO2008080957A1 (en) * | 2006-12-27 | 2008-07-10 | Lenze Automation Gmbh | Drive device comprising a plurality of drives and regulating system for this overall drive |
| CN101772744B (en) * | 2006-12-27 | 2014-06-04 | 伦茨自动化有限责任公司 | Drive device comprising a plurality of drives and regulating system for this overall drive |
| US8952645B2 (en) | 2006-12-27 | 2015-02-10 | Lenze Automation Gmbh | Drive device comprising a plurality of drives and regulating system for this overall drive |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9124181D0 (en) | 1992-01-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |