Collision detecting method

• US 5,719,479 A
• Filed: 08/24/1995
• Issued: 02/17/1998
• Est. Priority Date: 08/24/1994
• Status: Expired due to Term

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Kanno, Ichiro, Arita, Soichi, Kato, Tetsuaki
• Primary Examiner(s): Sircus, Brian
• Application Number:
  US08/518,689
• Time in Patent Office: 908 Days
• Field of Search: 318/560, 318/561, 318/563, 318/566, 318/568.11, 318/568.2, 318/568.21, 318/568.22, 318/606-610, 318/432-434, 364/148-152, 364/157, 364/159-166, 364/184, 364/185, 364/474.16, 364/474.19, 395/91, 73/862.192, 73/862.193
• US Class Current: 318/563
• CPC Class Codes: G05B 19/19 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
• CPC Class Codes: G05B 19/4061 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 2219/37624 Detect collision, blocking by measuring change of velocity or torque
• CPC Class Codes: G05B 2219/41128 Compensate vibration beam, gantry, feedback of speed of non driven end
• CPC Class Codes: G05B 2219/41381 Torque disturbance observer to estimate inertia
• CPC Class Codes: G05B 2219/41395 Observe actual position to estimate compensation torque

Abstract

A collision detecting method, in which a collision of a driven body driven by a servomotor is detected by a disturbance estimating observer. The method obtains a disturbance component which can be known in advance, subtracts the disturbance component from an input torque to generate a modified torque, and inputs the modified torque to a distrubance estimating observer.

Claims

1. A collision detecting method, in which a collision of a control object including a moving part and a servomotor is detected by a disturbance estimating observer, comprising the steps of:

applying an input torque to the servomotor to drive the moving part and thereby produce disturbances in the control object;

obtaining a disturbance component known in advance from said disturbances produced in the control object;

subtracting said disturbance component from said input torque to generate a modified torque; and

inputting said modified torque to the disturbance estimating observer which estimates only true indefinite disturbances to detect the collision of said moving part.

2. A collision detecting method according to claim 1, wherein said disturbance component is a nonlinear disturbance in said control object.

3. A collision detecting method according to claim 2, wherein said nonlinear disturbance includes at least one of a gravity torque, a coupling torque, and a dynamic friction torque.

4. A collision detecting method according to claim 1, wherein said disturbance component is a disturbance produced by said vibration system in said control object.

5. A collision detecting method according to claim 4, wherein said vibration system disturbance is a torque for activating an arm end.

6. A collision detecting method according to claim 1, wherein said disturbance component includes a nonlinear disturbance in said control object and a disturbance produced by a vibration system.