# US 9,434,075 B2 · Method for operating a multi-limb manipulator

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- Number: US 9,434,075 B2
- Document ID: US9434075B2
- Status: Granted
- Kind: B2
- Application number: 14/494,836
- Filed: 2014-09-24
- Published: 2015-03-26
- Granted: 2016-09-06
- Earliest claimed: 2013-09-25
- Assignees: Festo AG & Co.
- Applicants: FESTO AG & Co. KG
- Inventors: Matthias Doll; Armin Hartmann; Rudiger Neumann
- Web page: https://patentgrep.com/patent/US9434075B2

## CPC

- B25J 9/1682: {Dual arm manipulator; Coordination of several manipulators}
- B25J 9/163: {learning, adaptive, model based, rule based expert control}
- G05B 13/04: involving the use of models or simulators
- G05B 2219/42062: Position and speed and current
- Y10S 901/02: Arm motion controller
- Y10S 901/15: Jointed arm
- Y10S 901/28: Joint
- B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50})
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A method for operating a multi-limb manipulator which includes electric actuators assigned to manipulator limbs, control units assigned to the actuators, including: the provision of desired movement values for the actuator to an actuator dynamic model and the determination of an electric desired current value for the actuator, the transfer of the desired current value to a controller designed for outputting an actuator current to the actuator with the inclusion of the desired current value and of a measured actual current value and a measured actual position of the actuator, wherein a difference between the desired current value and the actual current value is determined as a required positional deviation, and wherein the positional deviation is added to the desired distance fed into the actuator dynamic model to facilitate a diversion movement of the manipulator limb operated by the actuator on the occurrence of an external disturbing force.

## Claims

### Claim 1

A method for operating a multi-limb manipulator which comprises at least one electric actuator for introducing a relative movement into adjacent manipulator limbs, and a control unit comprising a controller for a controlled energy supply to the at least one electric actuator, the method comprising the steps of:
providing desired movement values for the at least one electric actuator to an actuator dynamic model, the desired movement values including a desired distance and at least one of a desired velocity and a desired acceleration for the at least one electric actuator;
determining an electric desired current value in the actuator dynamic model, the electric desired current value being an amount of current necessary for the at least one electric actuator in order to obtain the desired movement values for the at least one electric actuator;
transferring the electric desired current value or the electric desired current value and the desired movement values to the controller of the control unit;
determining an actuator current demand in the controller, the determined actuator current demand being based on the electric desired current value and on a measured actual current value and on a measured actual position of the at least one electric actuator;
outputting the actuator current demand from the controller to the at least one electric actuator;
determining a difference between the electric desired current value and the measured actual current value;
converting the determined difference between the electric desired current value and the measured actual current value into a required positional deviation of the at least one electric actuator; and
adding the required positional deviation to the desired distance provided to the actuator dynamic model in order to facilitate a diversion movement of the at least one manipulator limb operated by the at least one electric actuator on an occurrence of an external disturbing force.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the multi-limb manipulator comprises a plurality of the electric actuators and the actuator dynamic model is designed to take into account interactions between all of the electric actuators for determining the spatial position of the manipulator, and wherein, for each of the electric actuators, individual desired movement values are made available including a desired distance and at least one of desired velocity and a desired acceleration, and wherein, for each of the electric actuators, an individual desired current value is calculated and transferred to an individual controller in order to determine an individual actuator current with the inclusion of a measured actual current value and a measured actual position of the respective actuator, wherein a difference between the desired current value and the actual current value of the respective actuator is converted into a positional deviation of that actuator, which is added to the desired distance in order to facilitate a diversion movement of the actuator on the occurrence of an external disturbing force.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the electric a desired current value is determined for a holding force or for a movement of the at least one electric actuator for each spatial position of the manipulator and for each actuator position, using the actuator dynamic model and the individual desired movement values for the actuator.

### Claim 4 (depends on 2)

The method according to claim 2, wherein a spatial position and an actuator position of all of the plurality of electric actuators interacting with one another are taken into account when determining the electric desired current value for a respective actuator.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the difference determined between the electric desired current value and the measured actual current value is converted into the required positional deviation of the at least one electric actuator only if the determined difference exceeds a presettable threshold value.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the difference determined between the electric desired current value and the measured actual current value is converted into the required positional deviation of the at least one electric actuator in a filter stage, the filter stage comprising a damped spring-mass oscillator for smoothing and damping the progression in time of the determined difference.

### Claim 7 (depends on 2)

The method according to claim 2, wherein all of the plurality of electric actuators are assigned a respective control unit, each control unit determining the electric desired current value for the respective actuator, and wherein each control unit includes a respective actuator dynamic model designed to take into account the interactions of all electric actuators mounted on the manipulator, using the measured actual current value and the measured actual position of the respective actuator.

### Claim 8 (depends on 2)

The method according to claim 2, wherein all of the plurality of electric actuators are assigned a respective control unit, each control unit determining the electric desired current value for the respective actuator, and wherein each control unit includes a respective actuator dynamic model designed to take into account the interactions of all, electric actuators mounted on the manipulator, including all measured actual currents and all measured actual positions of the electric actuators mounted on the manipulator.

### Claim 9 (depends on 7)

The method according to claim 7, wherein the electric desired current value for each of the plurality of electric actuators is determined by a plurality of the respective control units for a given movement situation of the actuators determining the spatial position of the manipulator, and wherein the electric desired current values determined by the plurality of the respective control units are compared.