US4769583A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motion control system with minimum time path generation
Assignee: Motors Liquidation Co
•
Filing: 1987-05-01
•
Granted: 1988-09-06
•
Expires: 2007-05-01
Abstract
Abstract A minimum time path generation routine for a motion control system, where the routine is uniquely adapted for use in a digital mechanization.
Inventors
- 👤 Robert M. Goor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:14
CPC Classifications
G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/19; G05B19/21; G05B19/23; G05B19/231; G05B19/237
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
273 words
A motion control path generation method for defining third-order trajectory position, velocity and acceleration parameters y, y' and Y" for steering an output member of a servo mechanism from a current position y(0) to a target position Y, such method comprising the steps of: defining a limit W on the third derivative y"' of the trajectory position y in relation to the ability of the servo mechanism to change the output member acceleration; defining a curve C containing the set of all trajectory parameters y, y' and y" which can be steered to the target position Y, with y"'=±W; defining a surface S containing the set of all trajectory parameters y, y' and y" which can be steered to the curve C, with y"'=±W; successively integrating y"' to determine the trajectory acceleration, velocity and position parameters y", y' and y; setting the magnitude and sign of y"' at periodic time intervals dt such that (1) the trajectory approaches the surface S prior to coincidence of the output member position y(0) with the surface S, (2) the trajectory follows the surface S toward the curve C after coincidence of the output member position y(0) with the surface S, but prior to coincidence of the output member position y(0) with the curve C, and (3) the trajectory follows the curve C toward the target position Y after coincidence of the output member position y(0) with the curve C; and setting the trajectory velocity, acceleration and jerk parameters y', y" and y"' to zero when the output member position y(0) coincides with the target position Y, thereby to prevent further adjustment of the output member position.
Claim 2
Dependent Claim
273 words
A motion control path generation method for defining third-order trajectory position, velocity and acceleration parameters y, y' and Y" for steering an output member of a servo mechanism from a current position y(0) to a target position Y, such method comprising the steps of: defining a limit W on the third derivative y"' of the trajectory position y in relation to the ability of the servo mechanism to change the output member acceleration; defining a curve C containing the set of all trajectory parameters y, y' and y" which can be steered to the target position Y, with y"'=±W; defining a surface S containing the set of all trajectory parameters y, y' and y" which can be steered to the curve C, with y"'=±W; successively integrating y"' to determine the trajectory acceleration, velocity and position parameters y", y' and y; setting the magnitude and sign of y"' at periodic time intervals dt such that (1) the trajectory approaches the surface S prior to coincidence of the output member position y(0) with the surface S, (2) the trajectory follows the surface S toward the curve C after coincidence of the output member position y(0) with the surface S, but prior to coincidence of the output member position y(0) with the curve C, and (3) the trajectory follows the curve C toward the target position Y after coincidence of the output member position y(0) with the curve C; and setting the trajectory velocity, acceleration and jerk parameters y', y" and y"' to zero when the output member position y(0) coincides with the target position Y, thereby to prevent further adjustment of the output member position.
Claim 3
Dependent Claim
83 words
The method set forth in claim 1, wherein the step of setting the magnitude and sign of y"' prior to coincidence of the output member position y(0) with the surface S comprises the steps of: detecting an imminent crossing of the trajectory and the surface S; and in response to such detection, reducing the magnitude of y"' in relation to the distance e s between the output member position y(0) and the surface S such that the trajectory exponentially approaches the surface S.
Claim 4
Dependent Claim
74 words
The method set forth in claim 2, where the step of detecting an imminent crossing of the trajectory and the surface S comprises the steps of: computing the values of the trajectory position y(t+dt) and surface S(t+dt) for the next time interval dt; and adjusting the magnitude of y"' in relation to the difference y(t+dt)-S(t+dt) when such difference indicates that a crossing of the surface will have occurred by the next time interval dt.
Claim 5
Dependent Claim
88 words
The method set forth in claim 2, where the time interval dt is dt seconds and the step of detecting an imminent crossing of the trajectory and the surface S comprises the steps of: projecting the values of the trajectory position y(t+dt) and surface S(t+dt) for the next interval based on previous values of y(t) and S(t); and adjusting the magnitude of y"' in relation to the difference y(t+dt)-S(t+dt) when such difference indicates that a crossing of the surface S will have occurred by the next time interval.
Claim 6
Dependent Claim
64 words
The method set forth in claim 2, where, upon detection of an imminent crossing of the trajectory and the surface S, the magnitude of y"' is reduced in relation to the time interval dt and the distance e s such that the time rate of change e s ' of the distance e s varies in substantial proportion to the distance e s .
Claim 7
Dependent Claim
61 words
The method set forth in claim 1, wherein the step of setting the magnitude and sign of y"' after coincidence of the output member position y(0) with the surface S, but prior to coincidence of the output member position y(0) with the curve C comprises the steps of: reversing the sign of y"'; and resetting the magnitude of y"' to W.
Claim 8
Dependent Claim
115 words
The method set forth in claim 6, wherein the step of setting the magnitude and sign of y"' after coincidence of the output member position y(0) with the surface S, but prior to coincidence of the output member position y(0) with the curve C comprises the further steps of: determining the value of the curve C for the next time interval C(t+dt) to detect if a crossing of the curve C will have occurred; and in response to such detection defining a new magnitude of y"' based on an interpolation of the trajectory position over the time interval dt so that the trajectory will coincide with the curve C substantially at such next time interval.
Claim 9
Dependent Claim
47 words
The method set forth in claim 1, wherein the step of setting the magnitude and sign of y"' after coincidence of the output member position y(0) with the curve C includes the steps of: reversing the sign of y"'; and setting the magnitude of y"' to W.
Claim 10
Dependent Claim
86 words
The method set forth in claim 8, wherein the step of setting the magnitude and sign of y"' after coincidence of the output member position y(0) with the curve C further includes the steps of: defining a cubic approximation of the distance between the output member position y(0) and the target position Y; and setting the magnitude of y"' in relation to such cubic approximation such that the output member position y(0) coincides with the target position Y in an integral number of time intervals dt.
Claim 11
Dependent Claim
79 words
The method set forth in claim 1, including the steps of: defining velocity limit boundary curves for the trajectory in the y', y" phase plane in relation to the velocity limit V of the servo mechanism; and reversing the sign of y"' when the velocity and acceleration parameters y', y" coincide with the velocity limit boundary curves, thereby to invoke the maximum deceleration of the servo mechanism output member to keep the trajectory velocity parameter within the velocity limit.
Claim 12
Dependent Claim
86 words
The method set forth in claim 10, including the steps of: determining the value of the velocity and acceleration parameters y'(t+dt) and y"(t+dt) for the next time interval to detect if a crossing of the velocity boundary curves will have occurred; and in response to such detection defining a new magnitude of y"' based on an interpolation of the trajectory velocity and acceleration over the time interval dt so that the trajectory will coincide with the respective velocity boundary curve substantially at such next time interval.
Claim 13
Dependent Claim
74 words
The method set forth in claim 1, including the steps of: defining an acceleration limit A for the acceleration parameter y" of the trajectory in relation to the ability of the servo mechanism to accelerate the output member; and reducing the magnitude of y"' to zero when the acceleration parameter y" of the trajectory coincides with the acceleration limit A, thereby to maintain the trajectory acceleration parameter substantially constant at the acceleration limit A.
Claim 14
Dependent Claim
86 words
The method set forth in claim 12, including the steps of: determining the value of the acceleration parameter y"(t+dt) for the next time interval dt to detect if a crossing of the acceleration limit A will have occurred by the next time interval; and in response to such detection defining a new magnitude of y"' based on an interpolation of the trajectory acceleration over the time interval dt so that the trajectory acceleration parameter will coincide with the acceleration limit substantially at such next time interval.
Claim 15
Dependent Claim
95 words
The method set forth in claim 1, including the steps of: defining an acceleration limit A for the acceleration parameter y" of the trajectory in relation to the ability of the servo mechanism to accelerate the output member; and redefining the curve C to include a boundary of constant acceleration equal to the acceleration limit A if it is determined that the acceleration parameter y" of the trajectory will exceed the acceleration limit before the trajectory crosses the curve C, whereby the acceleration parameter of the trajectory is automatically limited to the acceleration limit A.
References Cited (Backward Citations)
US3882304A
Cited
US4262336A
Cited
US4449196A
Cited
US4603286A
Cited
US4689756A
Cited
US4663726A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-06 | 1992-03-07 | 1992-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-06 | 1996-03-07 | 1996-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-06 | 2000-03-07 | 2000-09-06 | $7700.00 | Window Closed / Lapsed |