Robot controller

• US 6,340,875 B1
• Filed: 12/22/1999
• Issued: 01/22/2002
• Est. Priority Date: 03/25/1999
• Status: Expired due to Term

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Watanabe, Atsushi, Kato, Tetsuaki
• Primary Examiner(s): Fletcher, Marlon T.
• Assistant Examiner(s): Leykin, Rita
• Application Number:
  US09/468,641
• Time in Patent Office: 762 Days
• Field of Search: 318/568.11, 318/568.18, 318/568.2, 318/568.21
• US Class Current: 318/568.11
• CPC Class Codes: B25J 9/163 learning, adaptive, model based, rule based expert control
• 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

Abstract

A robot controller which controls a process controlled variable of an operational tool mounted on a robot in synchronism with the robot motion. The position of each axis of the robot is detected by a sensor such as a position detector. In a calculating section, motion variables such as position P_n, velocity v_n and acceleration α_n of a tool center point (TCP) are detected from the respective positions of the robot axes. An ideal output (target value) of a sensor for detecting a controlled variable to be controlled in accordance with the motion state is determined in a calculating section. A sensor output is subtracted from the target value to determine a deviation. The deviation is multiplied by a proportional gain K to determine a manipulated variable. By using this manipulated variable, the process of an arc welding machine, sealing machine, or laser beam machine in which a tool is mounted on a distal end of a robot wrist is controlled. The target value is determined in accordance with the change of motion state of the robot, and feedback control is carried out so as to follow the target value so that uniform operation is achieved.

Claims

1. A robot controller comprising:

motion control means for moving an operational tool mounted on a robot with respect to an object;

supply means for supplying energy to be applied to the object through the operational tool;

supply control means for issuing a supply command to said supply means; and

means for feeding back a parameter representing power of the energy supplied through the operational tool to alter the supply command based on the fed back parameter and a target value of the fed back parameter, the target value being dynamically determined based on a motion variable of a tool center point of the operational tool in motion obtained by said motion control means.

2. A robot controller for an arc welding operation according to claim 1, wherein the motion variable is a speed of a control point of the robot relative to the object, said supply means is a power source for supplying a welding current, and the parameter is the welding current.

3. A robot controller for a laser welding operation according to claim 1, wherein the motion variable is a speed of a control point of the robot with respect to the object, said supply means is a laser oscillator for supplying a laser beam, and the parameter is an excitation current of said laser oscillator.

4. A robot controller for controlling a robot comprising:

motion control means for moving an operational tool with respect to an object;

supply means for supplying energy to an operational substance to be fused so as to apply the fused operational substance to the object through the operational tool;

supply control means for issuing a supply command to said supply means; and

means for feeding back a parameter representing power of the energy supplied from the operational tool to alter the supply command based on the fed back parameter and a target value of the fed back parameter, the target value being dynamically determined based on a motion variable of a tool center point of the operational tool in motion obtained by said motion control means.

5. A robot controller for arc welding according to claim 4, wherein the motion variable is a speed of a control point of the robot relative to the object, said supply means is a power source for supplying a welding current to filler metal, and the parameter is the welding current.

6. A robot controller for controlling a robot comprising:

motion control means for moving an operational tool with respect to an object;

supply means for supplying an operational substance to be applied to the object through the operational tool;

supply control means for issuing a supply command to said supply means; and

means for feeding back a parameter representing a supply rate of the operational substance from the operational tool to alter the supply command based on the fed back parameter and a target value of the fed back parameter, the target value being dynamically determined based on a motion variable of a tool center point of the operational tool in motion obtained by said motion control means.

7. A robot controller for a sealing operation according to claim 6, wherein the operational variable is a speed of a control point of the robot with respect to the object, said supply means is an electric motor for driving a pump for supplying a sealing material, and the parameter is a pressure of the sealing material at an outlet of the operational tool.

8. A robot controller for a painting operation according to claim 6, wherein the operational variable is a speed of a control point of the robot with respect to the object, said supplying means is an electric motor for driving a pump for supplying paint, and the parameter is a pressure of the paint at an outlet of the operational tool.

9. A robot controller comprising:

a motion control unit moving an operational tool mounted on a robot with respect to an object;

a supply unit supplying energy to be applied to the object through the operational tool;

a supply control unit issuing a supply command to said supply unit; and

a feedback unit feeding back a parameter representing power of the energy supplied through the operational tool to alter the supply command based on the fed back parameter and a target value of the fed back parameter, the target value being dynamically determined based on a motion variable of a tool center point of the operational tool in motion obtained by said motion control unit.

10. A robot controller for controlling a robot comprising:

a motion control unit moving an operational tool with respect to an object;

a supply unit supplying energy to an operational substance to be fused so as to apply the fused operational substance to the object through the operational tool;

a supply control unit issuing a supply command to said supply unit; and

a feedback unit feeding back a parameter representing power of the energy supplied from the operational tool to alter the supply command based on the fed back parameter and a target value of the fed back parameter, the target value being dynamically determined based on a motion variable of a tool center point of the operational tool in motion obtained by said motion control unit.

11. A robot controller for controlling a robot comprising:

a motion control unit moving an operational tool with respect to an object;

a supply unit supplying an operational substance to be applied to the object through the operational tool;

a supply control unit issuing a supply command to said supply unit; and

a feedback unit feeding back a parameter representing a supply rate of the operational substance from the operational tool to alter the supply command based on the fed back parameter and a target value of the fed back parameter, the target value being dynamically determined based on a motion variable of a tool center point of the operational tool in motion obtained by said motion control unit.

12. A controller for a robot having a tool mounted on an arm of the robot for operating on an object, comprising:

a supply controller providing a supply command to the object; and

a feedback unit feeding back a parameter to be controlled, wherein the supply command is based upon the fed back parameter and a target value of the parameter to be controlled, the target value being dynamically determined based on a motion variable of a tool center point of the tool in motion.

13. A method of controlling a robot having a tool mounted on an arm of the robot for operating on an object, comprising:

providing a supply command to the object; and

feeding back a parameter to be controlled, wherein the supply command is based upon the fed back parameter and a target value of the parameter to be controlled, the target value being dynamically determined based on a motion variable of a tool center point of the tool in motion.