Method for controlling at least one servomotor, associated control device, robot and computer program product

Patent metadata

Field	Value
Publication number	US-12109699-B2
Application number	US-202117795458-A
Country	US
Kind code	B2
Filing date	Jan 13, 2021
Priority date	Jan 27, 2020
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

A method for controlling a servomotor with a converter includes monitoring a circuit of a direct-voltage DC link that is connected to an input circuit for flow of an electric current; switching off a first switching device to end the supply of the direct-voltage DC link from an electrical grid if a stop signal occurs; braking the servomotor by control of power semiconductor switches of an inverter circuit in a regenerative braking operation, to reduce the rotation speed of the servomotor, if the monitoring detects that an electric current is not flowing after the first switching device has been switched off; and switching off a second switching device to prevent feeding electrical energy from the direct-voltage DC link into the servomotor if the monitoring detects a flow of electric current after the first switching device has been switched off.

First claim

What is claimed is:

1. A method for controlling at least one servomotor using a converter, the method comprising:
obtaining a converter, the converter comprising:
an input circuit connected to an electrical grid,
a direct-voltage DC link operatively coupled for receiving electrical energy from the input circuit,
a first switching device which is designed, in its switched-on state, to feed the direct-voltage DC link with electrical energy from the input circuit and, in its switched-off state, to prevent a feed of the direct-voltage DC link from the electrical grid so that no electrical energy from the electrical grid reaches the direct-voltage DC link,
at least one inverter circuit operatively coupled for receiving electrical energy from the direct-voltage DC link and has controllable power semiconductor switches for electrically controlling the at least one servomotor, and
a second switching device which is designed, in its switched-on state, to feed the at least one servomotor with electrical energy from the inverter circuit in order to drive the at least one servomotor and, in its switched-off state, to prevent a driving of the at least one servomotor so that no electrical energy driving the at least one servomotor goes from the inverter circuit to the servomotor;

monitoring a circuit of the direct-voltage DC link that is connected to the input circuit for the flow of an electric current;
switching off the first switching device in response to the occurrence of a stop signal, in order to end the supply of the direct-voltage DC link from the electrical grid;
braking the at least one servomotor by controlling the power semiconductor switches of the inverter circuit in a generative braking operation, or via a short-circuit braking, in order to reduce the rotation speed of the at least one servomotor, in response to detecting with the monitoring that an electric current is not flowing in the circuit that connects the input circuit to the direct-voltage DC link after the first switching device has been switched off; and
switching off the second switching device in order to prevent a feeding of electrical energy from the direct-voltage DC link into the at least one servomotor in response to detecting with the monitoring a flow of electric current in the circuit that connects the input circuit to the direct-voltage DC link after the first switching device has been switched off.

2. The method of claim 1 , wherein the converter is designed as a frequency converter, the electrical grid is an alternating-voltage grid, and the input circuit is designed as a rectifier circuit, the method further comprising:
monitoring a circuit of the direct-voltage DC link and that is connected to the rectifier circuit for the flow of an electric current;
switching off the first switching device in order to end the supply of the direct-voltage DC link from the alternating-voltage grid in response to the occurrence of a stop signal;
braking the at least one servomotor by controlling the power semiconductor switches of the inverter circuit in a generative braking operation, or via a short-circuit braking, in order to reduce the rotation speed of the at least one servomotor, in response to detecting with the monitoring that an electric current is not flowing in the circuit that connects the rectifier circuit to the direct-voltage DC link after the first switching device has been switched off; and
switching off the second switching device in order to prevent a feeding of electrical energy from the direct-voltage DC link into the at least one servomotor in response to detecting with the monitoring a flow of an electric current in the circuit that connects the rectifier circuit to the direct-voltage DC link after the first switching device has been switched off.

3. The method of claim 2 , wherein monitoring the circuit that connects the rectifier circuit to the direct-voltage DC link for a flow of an electric current comprises monitoring by a single current measurement in one of two lines that connect the rectifier circuit to the direct-voltage DC link.

4. The method of claim 2 , wherein monitoring the circuit that connects the rectifier circuit to the direct-voltage DC link for a flow of an electric current comprises monitoring redundantly via a duplicate current measurement in both a first line connecting the rectifier circuit to the direct-voltage DC link and in a second line connecting the rectifier circuit to the direct-voltage DC link.

5. A method for controlling at least one servomotor using a converter, the method comprising:
obtaining a converter, the converter comprising:
an input circuit connected to an electrical grid,
a direct-voltage DC link operatively coupled for receiving electrical energy from the input circuit,
a first switching device which is designed, in its switched-on state, to feed the direct-voltage DC link with electrical energy from the input circuit and, in its switched-off state, to prevent a feed of the direct-voltage DC link from the electrical grid so that no electrical energy from the electrical grid reaches the direct-voltage DC link,
at least one inverter circuit operatively coupled for receiving electrical energy from the direct-voltage DC link and has controllable power semiconductor switches for electrically controlling the at least one servomotor, and
a second switching device which is designed, in its switched-on state, to feed the at least one servomotor with electrical energy from the inverter circuit in order to drive the at least one servomotor and, in its switched-off state, to prevent a driving of the at least one servomotor so that no electrical energy driving the at least one servomotor goes from the inverter circuit to the servomotor;

monitoring a circuit of the direct-voltage DC link that is connected to the input circuit for the flow of an electric current;
switching off the first switching device in response to the occurrence of a stop signal, in order to end the supply of the direct-voltage DC link from the electrical grid;
braking the at least one servomotor by controlling the power semiconductor switches of the inverter circuit in a generative braking operation, or via a short-circuit braking, in order to reduce the rotation speed of the at least one servomotor, in response to detecting with the monitoring that an electric current is not flowing in the circuit that connects the input circuit to the direct-voltage DC link after the first switching device has been switched off; and
switching off the second switching device in order to prevent a feeding of electrical energy from the direct-voltage DC link into the at least one servomotor in response to detecting with the monitoring a flow of electric current in the circuit that connects the input circuit to the direct-voltage DC link after the first switching device has been switched off;
wherein the converter is designed as a frequency converter, the electrical grid is an alternating-voltage grid, and the input circuit is designed as a rectifier circuit, the method further comprising:
monitoring a circuit of the direct-voltage DC link and that is connected to the rectifier circuit for the flow of an electric current,
switching off the first switching device in order to end the supply of the direct-voltage DC link from the alternating-voltage grid in response to the occurrence of a stop signal,
braking the at least one servomotor by controlling the power semiconductor switches of the inverter circuit in a generative braking operation, or via a short-circuit braking, in order to reduce the rotation speed of the at least one servomotor, in response to detecting with the monitoring that an electric current is not flowing in the circuit that connects the rectifier circuit to the direct-voltage DC link after the first switching dev

Assignees

• Kuka Deutschland Gmbh

Inventors

• Pfister Thomas
• Langhans Michael
• Fischer Andreas

Classifications

• G05B2219/40269

  Naturally compliant robot arm · CPC title

• G05B2219/34013

  Servocontroller · CPC title

• G05B19/4155

  characterised by program execution, i.e. part program or machine function execution, e.g. selection of a program · CPC title

• B25J9/1615

  characterised by special kind of manipulator, e.g. planar, scara, gantry, cantilever, space, closed chain, passive/active joints and tendon driven manipulators · CPC title

• B25J9/0048

  with kinematics chains of the type rotary-rotary-rotary · CPC title