Active damping of a measuring device

• US 10,620,003 B2
• Filed: 04/28/2015
• Issued: 04/14/2020
• Est. Priority Date: 04/28/2015
• Status: Active Grant

• Current Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Original Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Inventors: Sprenger, Bernhard, Iseli, Claudio
• Primary Examiner(s): Le, John H
• Application Number:
  US15/570,360
• Publication Number:
  US 20180149473A1
• Time in Patent Office: 1,813 Days
• Field of Search: 702152, 702155, 702 95, 33503, 356601
• CPC Class Codes: G01B 21/045 Correction of measurements G01B9/02055 takes precedence
• CPC Class Codes: G01B 5/008 using coordinate measuring machines
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G05B 13/04 involving the use of models or simulators
• CPC Class Codes: G05B 19/402 characterised by control arrangements for positioning, e.g. centring a tool relative to a hole in the workpiece, additional detection means to correct position G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/39401 Machine tool coordinates to manipulator coordinates

Abstract

Method for providing avoiding of excitations of oscillations of a measuring machine and/or for reducing or damping such oscillations by actively controlling a driving unit of the measuring machine or actively controlling an actuation of an additionally attached actuator. The method using information about an actual state of the measuring device, the actual state is derived based on a dynamic model and/or by use of a suitable sensor unit. A state controller, an actuator or a frequency-filtering element are used for counteracting or preventing oscillations.

Claims

1. A method for controlling a relative movement of at least two structural components of a measuring device including a driving unit for providing movability at least of the two structural components relative to each other, the method comprising:

providing a dynamic state information for at least one of the two structural components by means of a dynamic model with a set of model state variables, the model state variables;

being related to a set of physical properties of at least one of the two structural components, and

providing determination of an actual state of at least one of the two structural components;

providing a model-based state controller for controlling the driving unit, the model-based state controller comprising a set of at least one controlling state variable which depends on the actual state;

deriving at least one controlling state variable of the set of at least one controlling state variable by a calculation at least based on the dynamic model;

generating a controlling parameter by use of the state controller based on the at least one derived controlling state variable, the controlling parameter being adapted to drive the driving unit so that the at least one derived controlling state variable or actual state is affected in defined manner, and

applying the controlling parameter to the driving unit so that the structural components are moved in defined manner relative to each other.

2. The method according to claim 1, further comprising:

deriving the at least one controlling state variable based on monitoring the model state variable; and

deriving a particular controlling state variable of the set of at least one controlling state variable by monitoring the model state variable; and

deriving the actual state by a calculation based on the dynamic model.

3. The method according to claim 1, further comprising:

deriving the at least one controlling state variable based additionally on a model-based estimation or on a measurement; and

deriving a particular controlling state variable of the set of at least one controlling state variable at least by a model-based estimation or measurement; and

deriving the actual state by a calculation based on the dynamic model.

4. The method according to claim 1, wherein at least one controlling state variable of the set of at least one controlling state variable is derived by measuring an excitation or an impact on the measuring device with a sensor or by calculation from a path trajectory.

5. The method according to claim 1, further comprising:

deriving the actual state for the at least one of the two structural components by measuring or estimating at least one of the physical properties and, therefrom, deriving at least one corresponding actual controlling state variable.

6. The method according to claim 1, wherein the at least one controlling state variable corresponds to the actual state.

7. The method according to claim 1, wherein the state controller comprises an observer which provides determination of the at least one controlling state variable, in particular wherein the observer is provided by a Kalman-Filter.

8. The method according to claim 1, wherein the dynamic model and the model-based state controller are implemented in combined manner.

9. The method according to claim 1, wherein an actual deflection of the measuring device is derived based on the dynamic model.

10. The method according to claim 1, wherein:

an actual velocity or acceleration of at least a part of the measuring device is derived based on the dynamic model, or

an actual position of a designated point of the measuring device is derived based on the dynamic model, or

measuring errors are compensated based on the dynamic model.

11. The method according to claim 1, wherein the measuring device is embodied as a coordinate measuring machine comprising:

a base,

a probe head,

a machine structure for linking the probe head to the base, and

at least one drive mechanism for providing movability of the probe head relative to the base, the drive mechanism representing the driving unit,

wherein the structural components are embodied as the base, the probe head, or the machine structure.

12. The method according to claim 1, wherein the measuring device is embodied as a geodetic measuring instrument, with:

a support structure being mounted on a base of the measuring instrument such that the support structure is pivotable about a first axis defined by the base,

a source of electromagnetic radiation for generating a measuring beam,

a directing unit for directing the measuring beam, the directing unit being arranged at the support structure as to provide pivotability of the directing unit about a second axis defined by the support structure, the second axis being basically perpendicular to the first axis, and

a measuring functionality for providing directing and guiding of the measuring beam in a predefined manner and measuring distances correspondingly.

13. The method according to claim 1, wherein the at least one model state variable defines at least one or a combination of the following factors:

acceleration,

velocity, in particular rotational,

position,

bending,

deformation,

displacement,

orientation,

temperature,

humidity,

torque,

force,

stiffness, and

mass.

14. The method according to claim 1, wherein the change of the at least one controlling state variable or the model state variable is derived by at least one of the following physical properties:

acceleration,

velocity,

position,

deflection,

torque and/or

force.

15. The method according to claim 1, further comprising;

monitoring the physical properties and providing monitored physical properties; and

calculating the actual state of at least the part of the measuring device based on at least the set of model state variables and the monitored physical properties.

16. A computer program product having computer-executable instructions for performing the method claim 1.

17. A coordinate measuring machine with an active damping functionality, the coordinate measuring machine comprising:

a base,

a probe head,

a machine structure with structural components for linking the probe head to the base;

at least one driving unit for providing movability of the probe head relative to the base; and

a coordinate measuring machine provided with a dynamic state information and comprising a controllable actuator for applying a defined force,

deriving an oscillation information about an actual oscillation of at least the part of a coordinate measuring machine based on the dynamic state information; and

determining a controlling parameter based on the derived oscillation information and based on the controlling parameter, providing a damping actuation by the actuator by inducing a defined force counteracting the actual oscillation,

wherein an actual state of at least the part of the coordinate measuring machine is determined based on the dynamic state information and the controlling parameter is based on the derived actual state, the controlling parameter being adapted to provide controlling of the actuator so that the actual state is affected in defined manner.

18. A method according to claim 17, wherein the actuator is attached to one of the structural components, the probe head, or the base, wherein the force is producible at the respective component.

19. The method according to claim 17, wherein the dynamic state information is provided for at least the part of a coordinate measuring machine by means of a dynamic model or an observer with a set of model state variables, the model state variables:

being related to a set of physical properties of at least the part of the coordinate measuring machine, and

representing an actual state of at least the part of the coordinate measuring machine.

20. The method according to claim 19, wherein the actual state of at least the part of the coordinate measuring machine is derived by a calculation based on the dynamic model or the observer.

21. The method according claim 17, wherein the dynamic state information is provided for at least a part of a coordinate measuring machine by means of a measurement by a sensor unit.

22. The method according to claim 21, wherein the sensor unit is attached to one of the structural components, the probe head, or the base.

23. The method according to claim 21, wherein the sensor unit and the actuator are attached to the same part of the coordinate measuring machine and are positioned closely to each other.

24. The method according claim 17, wherein the actual state is derived using information about a planned moving path.

25. The method according to claim 17, wherein a controlling signal is applied to the actuator, the controlling signal being derived based on the controlling parameter.

26. The method according to claim 17, wherein the actuator is designed as a voice coil, a piezo unit, a memory metal element, or a pneumatic element.