Control device and speed reducer system

Patent metadata

Field	Value
Publication number	US-10042343-B2
Application number	US-201514842407-A
Country	US
Kind code	B2
Filing date	Sep 1, 2015
Priority date	Sep 4, 2014
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

This application discloses a control device for controlling a motor configured to drive an oscillatory cyclo-speed reducer including an oscillatory gear portion formed with at least one hole at an eccentric position. The control device includes an angle acquirer for acquiring input information about an input rotational angle indicating a rotational angle of the motor, an estimator for estimating an angular error between the input rotational angle and an output rotational angle indicating a rotational angle of the oscillatory cyclo-speed reducer based on a quantity of the hole(s) and a corrector for determining a compensation current value in correspondence to the angular error and setting a magnitude of a current to be supplied to the motor by correcting a command current value using the compensation current value.

First claim

The invention claimed is:

1. A control device for controlling a motor configured to drive an oscillatory cyclo-speed reducer including an oscillatory gear portion which is provided with at least one hole at an eccentric position, the control device comprising:
an angle acquirer configured to acquire input information about an input rotational angle which indicates a rotational angle of the motor;
an estimator configured to estimate an angular error between the input rotational angle and an output rotational angle indicating a rotational angle of the oscillatory cyclo-speed reducer, the angular error being caused by a rigidity variation of the oscillatory gear portion resultant from a position of the at least one hole of the oscillatory gear portion, based on a hole number which indicates a quantity of the at least one hole, a number of internal teeth meshed with the oscillatory gear portion, a speed reduction ratio of the oscillatory cyclo-speed reducer, and an angular velocity of the motor; and
a corrector configured to determine a compensation current value in correspondence to the angular error, the corrector using the compensation current value to correct a command current value and set a magnitude of a current, which is supplied to the motor.

2. The control device according to claim 1 , wherein the angular error is an axial torsional vibration.

3. The control device according to claim 1 , wherein the angular error is a vibration component caused by the at least one hole.

4. The control device according to claim 1 , wherein the estimator includes a state observer which uses the input information and the magnitude of the current supplied to the motor as inputs to estimate the angular error.

5. The control device according to claim 4 , wherein the state observer uses a periodically varying disturbance factor as an input to estimate the angular error.

6. A control device for controlling a motor configured to drive an oscillatory cyclo-speed reducer including an oscillatory gear portion which is provided with at least one hole at an eccentric position, the control device comprising:
an angle acquirer configured to acquire input information about an input rotational angle which indicates a rotational angle of the motor;
an estimator configured to estimate an angular error between the input rotational angle and an output rotational angle indicating a rotational angle of the oscillatory cyclo-speed reducer based on a hole number which indicates a quantity of the at least one hole; and
a corrector configured to determine a compensation current value in correspondence to the angular error, the corrector using the compensation current value to correct a command current value and set a magnitude of a current, which is supplied to the motor,
wherein the oscillatory cyclo-speed reducer includes N p internal teeth which are meshed with the oscillatory gear portion and decelerates an angular velocity ω M of the motor by using a reduction ratio R g of the oscillatory cyclo-speed reducer;
wherein the hole number is expressed by a natural number k; and
wherein the estimator calculates an angular frequency ω d of an angular transmission error resulting from elastic deformation inside the oscillatory cyclo-speed reducer from Equation 1, the estimator using a discrete-time state-space model, which includes the angular frequency ω d as a matrix component, to estimate the angular error:

ω
d

=

kN
p

⁢

ω
M

R
g

.

[

Equation
⁢

⁢
1

]

7. The control device according to claim 6 , wherein the oscillatory gear portion includes N g oscillation gears; wherein each of the N g oscillation gears is provided with k e holes; and wherein the natural number k is calculated from “Equation 2”:
k=N g ×k e .  [Equation 2]

8. The control device according to claim 6 , wherein the estimator calculates an angular frequency ω d1 of an angular transmission error resulting from a manufacturing error of the oscillatory cyclo-speed reducer from Equation 3, the estimator using a discrete-time state-space model including the angular frequency ω d1 as a matrix component to estimate the angular error:

ω

d
⁢

⁢
1

=

N
p

⁢

ω
M

R
g

.

[

Equation
⁢

⁢
3

]

9. The control device according to claim 6 , wherein the corrector includes a torque calculator configured to calculate a torque vibration, which vibrates at the angular frequency ω d , from the angular error estimated by the estimator and spring characteristics of the oscillatory cyclo-speed reducer, and a current calculator configured to calculate the compensation current value to reduce the torque vibration.

10. The control device according to claim 9 , wherein the torque calculator extracts a frequency component varying at the angular frequency ω d from data about the angular error estimated by the estimator, the torque calculator using the extracted frequency component to calculate the torque vibration.

11. The control device according to claim 9 , wherein the current calculator generates current data indicating a magnitude of a compensation current from the torque vibration, the current calculator extracting a frequency component varying at the angular frequency ω d

Assignees

• National Univ Corporation Nagaoka Univ Of Technology
• Nabtesco Corp

Inventors

• Ohishi Kiyoshi
• Yokokura Yuki
• Hirano Yosei
• Nakamura Koji
• Sato Masataka

Classifications

• H02P23/12

  Observer control, e.g. using Luenberger observers or Kalman filters · CPC title

• G05B2219/25355

  Motor winding used as power transformator · CPC title

• G05B19/04 Primary

  Program control other than numerical control, i.e. in sequence controllers or logic controllers (G05B19/418 takes precedence) · CPC title

• G05D13/62

  characterised by the use of electric means, e.g. use of a tachometric dynamo, use of a transducer converting an electric value into a displacement {(electric motor control H02P)} · CPC title

• G05B2219/25052

  VCO voltage controlled oscillator · CPC title