US 2011/0054820 A1Published application

Method for compensating for angular transmission error of wave gear device

AssigneesHarmonic Drive Systems Inc., National University Corporation Nagoya Institute of Technology

InventorsKozo Sasaki, Yoshifumi Okitsu, Toshio Yajima, Makoto Iwasaki

Life of this patent

Estimating the term…

Loading patent…

Abstract

A positioning system (1) provided with an actuator (2) having a wave gear device (4) is driven and controlled by a semi-closed loop control for controlling the load position of a load device (5) based on the motor position of a motor shaft (31) of a motor (3). In a method for compensating for an angular transmission error by compensating for a motor shaft synchronous component θSync that occurs in synchrony with the motor position and is a relative rotation-synchronous component that includes an angular transmission error component of the wave gear device (4), the positioning system (1) is represented as a two-inertia model, and the motor shaft synchronous component θSync is represented as an oscillation source for producing a twisting action between the two inertia bodies in the two-inertia model. A motor current command iref is corrected by a compensation current command icomp calculated so as to allow the effect of the motor shaft synchronous component θSync on the load position to be compensated in this case, and a motor position command r is corrected by a motor position correction signal θcomp calculated in order to compensate for the effect of the motor shaft synchronous component θSync.

A method for compensating for an angular transmission error of a wave gear device in cases in which an actuator for reducing the speed of output rotation of a motor via the wave gear device and transmitting the output rotation to a load device is driven and controlled by a semi-closed loop control for controlling the position of the load shaft of the load device on the basis of the detected position of the motor shaft of the motor;

comprising the steps of:
determining a motor shaft synchronous component θSync occurring in synchrony with a motor position θm, which is a rotational position of the motor shaft, by Formula (A), the motor shaft synchronous component being an angular transmission error component that occurs in synchrony with the relative rotation of each constituent element of the wave gear device, and the motor shaft synchronous component being present even in cases in which torque is not applied to the wave gear device
θ
Sync

(
θ
m
)
=
∑
i
=
1
n

A
i

sin

(
k
i

θ
m
+
φ
i
)
;
(
A
)
representing the actuator as a two-inertia model constructed from a motor-side inertia body including the rotor of the motor and the input shaft of the wave gear device, and a load-side inertia body including the output shaft of the wave gear device and the load device;
applying the motor shaft synchronous component θSync (θm) calculated from the motor position θm as twisting between the motor-side inertia body and the load-side inertia body;
considering the motor shaft synchronous component θSync (θm) to be an oscillation source;
correcting a motor current command iref by a compensation current command icomp determined by Formula (B)
i
comp

(
s
)
=
C
i

(
s
)
s
2

θ
¨
Sync

(
s
)
,
(
B
)
where Cθ(s) is a transfer function, and
θ″Sync is the second-order differential of the motor shaft synchronous component;
and,
correcting the motor position command r by the motor position correction signal θcomp determined by Formula (C)
θ
comp

(
s
)
=
1
s
2

C
θ

(
s
)

θ
¨
Sync

(
s
)
,
(
C
)
where Cθ(s) is a transfer function;
whereby compensating for the effect of the motor shaft synchronous component θSync (θm) on the load position θl, which is the rotational position of the load shaft.

98 more elements

Facts

Application

12/865,297Filed 8 Mar 2010

Priority

JP 2009-093103 20097 Apr 2009

Published

3 Mar 2011

Term ends

Not estimatedThe source records don’t support an estimate.

Classification10 codes

G05B 19/404
Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to…
H02P 23/14
Arrangements or methods for the control of AC motors characterised by a control method other than vector control: estimation or adaptation of…
F16H 49/001
Other gearings: wave gearings, e.g. harmonic drive transmissions
G05B 2219/41117
Servomotor, servo controller till figures: cancel vibration during positioning of slide

Abstract

Claims1