WO2015024634A1

WO2015024634A1 - Energy-optimised configuration of a manipulator

Info

Publication number: WO2015024634A1
Application number: PCT/EP2014/002178
Authority: WO
Inventors: Stefan Roth
Original assignee: Kuka Roboter Gmbh
Priority date: 2013-08-20
Filing date: 2014-08-07
Publication date: 2015-02-26
Also published as: DE102013013847A1; CN105473289B; EP3036073A1; CN105473289A

Abstract

In a method according to the invention for configuring a manipulator process with a specified movement phase (9) and a variable movement phase (10), a kinematic variable of the manipulator process in the variable movement phase (10) is specified in such a way that an energy variable is reduced.

Description

description

Energy-optimized configuration of a manipulator

The present invention relates to a method for configuring a manipulator process, in particular a robot process, and a configuration means for configuring a manipulator process.

Manipulators, especially industrial robots, usually perform repetitive, structured tasks. For this purpose, a path of the manipulator is previously predetermined mostly via a manipulator control and a corresponding programming means. Such a web usually consists of several different track sections. If, for example, a plurality of adhesive traces are to be produced on a workpiece by a manipulator-guided adhesive dispenser, with the adhesive tracks being arranged geometrically such that each adhesive trace forms one side of a rectangle formed by the adhesive traces, each adhesive trace corresponds to a predetermined web segment which traveled during a corresponding predetermined movement phase becomes.

Between two predetermined adjacent phases of motion, the manipulator must adjust its direction of movement accordingly, for example, to start the next glue track. Different predetermined movement phases along the entire path usually do not only have different directions of movement, but may also have differences with regard to other states of the manipulator, in particular with respect to kinematic variables. These kinematic variables may in particular be positions, speeds and / or accelerations of the manipulator. In the above-mentioned example of a gluing process, such a difference may, for example, relate to a speed at which the manipulator places the gluing trace and over which the thickness of the gluing trace is modulated. The traces of adhesive can, for example, by a predetermined constant Speed of the manipulator can be realized, so that there is a glue trace constant thickness.

For the transition from a given movement phase to another accordingly usually adjustments of the direction and adjustments of one or more other kinematic variables of the manipulator are necessary.

The adjustments happen according to internal practice so far by the fact that the manipulator decelerates before the start of a new predetermined movement phase, adjusted its position accordingly, in particular a tool raises or lowers, and accelerates again. These adjustments are usually associated with energy intake and / or energy dissipation.

It is not always necessary or possible that the manipulator adapts its states only at the transition point between two predetermined movement phases. For example, at the transition between two predetermined movement phases, by which a change in direction of the web is defined, positional deviations of the manipulator from the predetermined track sections, between which the transition occurs, be allowed. It is known, the manipulator in these areas by a so-called "blending" or "Versch verschleiten" of a track section in a next track section to be such that the movement of the manipulator deviates during the transition from the predetermined track sections. In the above example, it can be avoided that the corner which exists in the event of a change of direction between two successive predetermined phases of movement at the transition point between the corresponding predefined track sections must be traversed with exact position. In this case, a manipulator process consists of given phases of movement and of variable phases of movement, which designates the transition between two predetermined phases of movement.

For example, EP 0 706 104 B1 teaches a method of smoothing non-tangential areas in programmed contours, particularly for use in numerically controlled machine tool controls. The course of the machine axes within the grinding element is determined approximately. the goal is it is to design a method for smoothing unsteady regions in programmed contours in such a way that as a result axis-velocity jumps occurring in the machine axes and the underlying acceleration pulses can be limited. The present invention has for its object to provide an improved manipulator process.

This object is achieved by a method for configuring a manipulator process having the features of claim 1. Claim 1 1, a configuration means, claim 12, a computer program for performing a corresponding method under protection, claim 13, a corresponding computer program product. The subclaims relate to preferred developments of the present invention.

A method according to the invention for configuring a manipulator process can be used in particular for configuring a robot process which is carried out by one or more, in particular cooperating, robots.

The manipulator process has one or more predetermined motion phases and one or more variable motion phases. Predetermined movement phases can be predetermined in advance or be based in particular on the basis of a processing and / or transport task, for example on the basis of a processing or transport path to be traveled by one or more robots, such as a gluing, welding or varnishing path or picking up or setting down on a conveyor belt. A variable movement phase in the sense of the present invention may in particular be a free transfer orbit of one or more robots, which transfers the robot (s) from a predetermined state to another predetermined state, in particular also a standstill, without, for example, based on a or several robots to be traveled processing or transport path to be specified. The variable movement phase can in particular also be a web on which no machining process takes place, such as gluing, welding or painting. Here, in particular, the transition of the predetermined states at the end of a previous movement phase and take place at the beginning of another subsequent predetermined movement phase. As transition in the sense of the present invention, the time of a change between a predetermined and a variable movement phase or between a variable and a predetermined movement phase is preferably referred to.

Accordingly, a kinematic variable of the manipulator process is predetermined at the transition between a variable movement phase and a preceding and / or subsequent predetermined movement phase. For example, the position and speed at the end of an adhesive strip and the position and speed at the beginning of an adhesive strip to be subsequently removed are predetermined by the bonding process, i. the specification of the bonding process has the form of an adhesive strip in the predetermined movement phase, in the variable movement phase the form of a transfer path to the next adhesive strip, and from the transition of this variable movement phase in the subsequent movement phase again the shape of an adhesive strip.

According to one aspect of the present invention, a kinematic variable is automatically set in one or more variable movement phases, in particular completely during one or more variable movement phases, in such a way that an energy quantity is reduced. Thus, for example, advantageously in a manipulator-based adhesion process, a kinetic energy of the robot at the end of an adhesive trace can be advantageously used to move the robot to a beginning of a next adhesive trace, without stopping it completely and thereby converting its kinetic energy unused into heat. A manipulator process in the sense of the present invention may be a process performed by a manipulator arrangement in a targeted manner, in particular an adhesion process, a welding application, a press-chaining process, a welding current, an operation of an axle or another drive. In this case, a manipulator arrangement can in particular comprise one or more manipulators, in particular robots, but also other devices, such as an additional axis, a conveyor belt, a tool, etc. A manipulator process can be a algorithmically executing information processing. In particular, a process may be a process controlled by a program which, in particular, requires a processor for execution, which is preferably provided by a control device. A movement phase in the sense of the invention is understood in particular to mean a time or path section of a manipulator process in which the states of the manipulator process have specific values. In the following, a state of the manipulator process is understood in particular to be a physical state of one or more devices involved in the manipulator process, in particular of one or more manipulators, that is to say a state of the manipulator arrangement. During a movement phase, such states have certain values. For example, one or more manipulators may have certain positions, speeds, accelerations, etc. These can be or at least partially predetermined. Likewise, states of the manipulator process may result from predetermined states and / or constraints of the manipulator process or devices involved. For example, one or more manipulators, particularly parts thereof, may have a certain potential energy and / or kinetic energy, and / or one or more states of a manipulator process, especially within certain limits, may be variable.

A specification within the meaning of the invention can comprise a, in particular automatic, specification, which can be effected in particular by a configuration means. Preferably, a specification is dependent on a state of the manipulator process, in particular a state of one or more manipulators of the manipulator arrangement and / or one or more tools of a manipulator of the manipulator arrangement. A default may be dependent on one or more workpieces of the manipulator assembly. Additionally or alternatively, a default may be communicated through a device that interacts with the manipulator assembly. An agent in the sense of the present invention may be designed in terms of hardware and / or software. In particular, the means may comprise a data or signal-connected, preferably digital, preferably with a memory and / or bus system. Processing, in particular microprocessor unit (CPU) and / or have one or more programs or program modules. The CPU may be configured to execute instructions implemented as a program stored in a memory system, to capture input signals from a data bus, and / or to output signals to a data bus. A storage system may comprise one or more, in particular different, storage media, in particular optical, magnetic, solid state and / or other non-volatile media. The program may be such that it is capable of embodying or executing the methods described herein so that the CPU may perform the steps of such methods and, in particular, configure or dictate the manipulator process.

A configuration means may comprise, in particular, a robot controller for one or more robots, in particular. Similarly, the configuration means may be a means cooperating with the robot controller, in particular a PC, which is preferably connected to an input interface. A configuration means can be set up in particular for configuring a manipulator process via a network, in particular the Internet.

A kinematic variable in the sense of the invention may be a state of the manipulator process. Preferably, a kinematic variable describes a position and / or movement of a point or a body in space, in particular one or more elements of the manipulator arrangement. A kinematic variable may thus be a position, a velocity, an acceleration and / or a time derivative of such a variable. A kinematic variable may also include dynamic variables, in particular parameters of a model of the manipulator process and / or the manipulator arrangement, in particular parameters of a differential equation and / or a transfer function. A kinematic variable may in particular also include a force or a moment. A kinematic variable can be one-dimensional or multi-dimensional. An energy quantity within the meaning of the invention comprises in particular a variable which describes an energetic state of a system, a field and / or parts thereof. For the purposes of the invention, an energy quantity may include any energy which may occur in connection with a machine, in particular a kinetic and / or a potential energy. In addition, an energy quantity may include, in particular, a loss energy. Additionally or alternatively, an energy quantity may include electrical energy or heat energy. An energy quantity may also include a derivative and / or an integral of another energy quantity, in particular an energy quantity may thus be a power. An energy quantity may be an image or a function of an energy, in particular a kinetic and / or a potential energy. In particular, such a mapping may include a merit function or a merit function of an optimization problem, in particular a minimization problem.

By the inventive specification of the kinematic variable for reducing an energy quantity within a variable motion phase transition phases, in particular between two predetermined movement phases, better, preferably energy optimal, can be specified. Advantageously, this can achieve a more efficient operation of a manipulator process. In addition or as an alternative, a more accurate and reliable operation of a manipulator process can be achieved, since mechanically optimized excitations, for example oscillations, in the manipulator arrangement are advantageously minimized or, in particular, only permitted where appropriate with an operator specification or by a correspondingly energy-optimal specification of a kinematic variable necessary to be complied with secondary conditions do not conflict.

In a preferred development, the manipulator process has two or more predetermined movement phases. In this case, the first predetermined movement phase ends, preferably immediately before the inventively predetermined variable motion phase begins. In one embodiment, the endpoint of the first predetermined motion phase and the starting point of the variable motion phase coincide in time. Additionally or alternatively, the second predetermined movement phase ends, preferably immediately, after the variable movement phase. In one embodiment, the end point of the variable motion phase and the starting point of the second predetermined motion phase coincide in time. Advantageously, by two by a Operator predetermined movement phases whose corresponding predetermined track sections are not related, are converted into each other.

Preferably, the manipulator process comprises a plurality of variable motion phases. In particular, these variable movement phases can each be separated by predetermined movement phases. For example, a process for gluing a rectangle may comprise four predetermined movement phases, between which four variable movement phases are arranged. Preferably, given movement phases and variable movement phases form a periodic manipulation process. Advantageously, this makes it easy to configure a periodic manipulator process, in particular sections.

In one embodiment of the method, a kinematic variable is predefined on the basis of several movement phases. In particular, these movement phases may include, in particular, predetermined movement phases. Additionally or alternatively, these movement phases may include variable movement phases, in particular. In one embodiment, a kinematic variable in a variable motion phase is predefined on the basis of all remaining variable motion phases and / or all predetermined motion phases of the manipulator process. In one embodiment, a kinematic variable is predefined on the basis of all other phases of motion. In particular, a specification of a kinematic variable can be carried out on the basis of a dynamic programming, wherein in particular the entire manipulator path, i. all phases of movement, be taken into account. For example, a speed during an adhesion process with four predetermined movement phases and four variable movement phases can be set in such a way that an energy provided by an energy store is used optimally for movement. Advantageously, this allows a variable motion phase to be easily configured, including a global constraint.

In a preferred development of the method optionally different kinematic variables are specified. In particular, in a variable movement phase, an acceleration can first be specified and then a speed or position. Similarly, optional and / or _q

alternately an acceleration, a speed and / or a force can be specified. In particular, a stop of the manipulator can be specified during a variable movement phase. In particular, a changeover of the predetermined kinematic variable during the variable movement phase, preferably under real-time conditions, be performed, thereby ensuring that the switch is completed within certain time limits. Preferably, a sequential switching between different kinematic variables is predetermined. In particular, a prioritization can be defined to select between different kinematic variables to be switched to. Advantageously, the variable movement phase can thereby be flexibly specified.

In a preferred development, the kinematic variable is predefined on the basis of a minimization of the energy quantity. For example, the electrical energy necessary for a manipulator bonding process can be minimized. In particular, the energy quantity can be described by a quality function, preferably as a quality vector function, which comprises a kinematic variable. Alternatively, the energy quantity can be described as a quality functional, which includes several functions of one or more kinematic variables. Additionally or alternatively, a kinematic variable may be predetermined to be adhered to as a constraint of an energy size optimization problem. Preferably, the kinematic variable is specified as extremal size. Such an extreme variable may in particular comprise a specific position or a function of a position, a maximum speed and / or a maximum acceleration or deceleration, which may not be exceeded, in particular, by a specific axis of the manipulator.

Such an extreme size can in particular also be a maximum force that can be applied to an object by a manipulator of the manipulator arrangement, which force must not be exceeded. In addition to a maximum size, a kinematic variable can also include a minimum size as an extreme variable, in particular a speed that can not be undershot. Advantageously, this can reduce the energy size to a local or global minimum be achieved, in particular in compliance with predetermined maximum and / or minimum values.

In a preferred development, the kinematic variable has a time derivation, in particular a speed and / or an acceleration, of one or more axes of one or more manipulators for carrying out the manipulator process. As a result, advantageously, an energy quantity of a specific axis of a manipulator and / or an additional axis or an entire manipulator can be reduced. An axis of a manipulator in the sense of the present invention may in particular comprise a drive train, preferably with a motor, a brake and / or sensors. Furthermore, an axis of a manipulator can also comprise a structural element of the robot, in particular an arm, a rocker and / or a tool. Axes may in particular also relate to an energy store of a manipulator arrangement. Axes of similar construction, which interact in particular with a manipulator, can represent additional axes of the manipulator.

In a preferred refinement, the kinematic variable is predefined on the basis of a compliance, a damping, a friction and / or an inertia of the axes of the manipulator to be moved. The kinematic variable can be specified in particular on the basis of an impedance, wherein an impedance in the sense of the invention comprises a mechanical quantity quotient of force and speed. In particular, energy stores inherent in the manipulator arrangement can be described as impedances which in particular contain energy which can be described on the basis of a kinematic variable and / or which is encompassed and reduced by an energy quantity. Advantageously, the structurally existing in a lightweight robot by elasticities energy storage can be used. In a preferred refinement, the kinematic variable is predefined on the basis of one or more generator phases of one or more manipulators, which are coupled to one or more other manipulators. A regenerative phase can be part of a predetermined or a variable movement phase. A regenerative phase preferably comprises Delays, which is caused by a motor brake of a manipulator. The resulting energy can be used to move another axis, in particular an axis of another robot, wherein both robots are preferably electrically, in particular via a DC link coupled. The energy-providing manipulator may in particular be part of the manipulator arrangement of the manipulator process or be operated in another manipulator arrangement. Preferably, a kinematic variable is predetermined so that an electrical energy which is provided by a generator phase, in particular completely, during the variable motion phase is transformed into mechanical energy, in particular kinetic and / or potential energy. Advantageously, an energy requirement by a manipulator during a manipulator process can thereby be reduced. In addition, it can be advantageously reduced dissipation of mechanical energy into heat energy. In a preferred refinement, the kinematic variable is predefined on the basis of available energy in an energy store. An energy store in the sense of the invention may in particular comprise an electrical energy store, preferably a battery, an accumulator and / or a capacitor. An energy store in the sense of the invention can also be a mechanical energy store which stores a kinetic and / or a potential energy. In particular, an energy store may be part of the manipulator arrangement. An energy store can also be understood to be one or more axes of a manipulator and / or an additional axis. In particular, energy can be stored in a rotating motor. Preferably, a kinematic variable is predetermined so that a manipulator receives and / or emits a certain energy during the variable movement phase. Advantageously, a movement of the variable movement phase can thereby be predetermined in such a way that absorption of energy from an external power supply is reduced or avoided.

In a preferred development features of the previous developments can be advantageously combined. Further developments and advantages, features and applications of the present invention will become apparent from the following description taken in conjunction with the figures. These show, partially schematized:

1 shows a method for configuring a manipulator process according to an embodiment of the present invention and

2 shows a method for configuring a manipulator process according to another embodiment of the present invention.

FIG. 1 shows a method for configuring a manipulator process according to an embodiment of the present invention. Shown is a Manipulatoranord- tion 1 with a workpiece 2 and a manipulator, which has two linear axes 3, 4, which can be moved orthogonal to each other, wherein an axis at its Tool Center Point (TCP) performs a glue gun 5. The aim of the manipulator process performed by the manipulator assembly is to place linear adhesive traces 6 (dashed line in Fig. 1) on the workpiece 2 to attach the workpiece 2 to another workpiece (not shown). In order to program the web for generating the adhesive traces 6 for the manipulator 3, 4, 5, a web of a rectangle 7 is firstly configured in the alternative. Thereafter, constraints are configured which are additional requirements for the web to produce desired adhesive traces 6. First, as constraints on certain positions 8 sections 9 on the rectangular track

7 defines which are to be maintained by the manipulator track. The specification of the movement of the manipulator on the four respectively by the corresponding positions

8 defined, straight track sections corresponds for the embodiment of the method shown here to four predetermined movement phases 9, during which the adhesive traces 6 are to be laid.

The movements on the corner track sections, which take place between the predetermined movement phases 9, represent the variable movement phases 10, during which in particular the track can be chosen freely and only subject to the positional constraints, end and start points 8 consecutive glue tracks 6 and predetermined movement phases 9 with each other to connect or transfer the glue gun 5 between them. As a global constraint, which must be observed both during the given movement phases 9 and during the variable movement phases 10, a minimum speed v_min can be predetermined, which should not be undershot. Taking into account these constraints, the total energy of the manipulator process as an energy quantity is minimized by varying the variable motion phases. If the solution to the optimization problem yields more than one solution to the four variable motion phases 10, another criterion is used to consolidate the alternative solutions into a single solution. In this embodiment, the solution is selected which can be realized with the highest average speed for the overall process. As a result of the method results for the variable movement phases 10 each an arcuate manipulator path, which coincides at the transitions 8 between predetermined movement phases 9 and variable movement phases 10 in particular position, direction, speed and acceleration, so that in particular during the transition no mechanical stimuli of the manipulator occur for example by jumps in the drive signals. As a further part of the solution results as a kinematic size, a speed trajectory for the axes 3, 4 of the manipulator, which at no time below the minimum predetermined speed v_min. The adhesive tracks 6 can thus be easily configured by an operator and produced with high quality by the manipulator process.

FIG. 2 shows a flowchart according to another embodiment of the method by which a welding application is carried out. Initially, in a step S10, a range is specified via [s tot] which a welding robot may not leave. In addition, predetermined motion phases s_vor (x, y, z) are defined in the cartesian coordinate system x, y, z of the robot by configuring various welds that the robot has to draw. The welds have a certain shape and must be pulled at a speed also given, so that a uniform weld. In a subsequent step S20, secondary conditions are defined which may apply to the entire welding process or only to one or more variable movement phases.

For the variable motion phases while track sections are given, which each connect the corresponding track sections of two predetermined movement phases together. Around each of these track sections a tubular variation area is defined. This variation range defines permissible deviations x, y, z from the path section which are permitted within the variable motion phases. Additionally or alternatively, a spherical variation range may be defined around each of the track points of these track sections.

Thereafter, a power P is defined as an energy quantity in a step S30. This power results from the product between the Cartesian speed realized by the robot and the force necessary to guide the welding gun. The kinematic variables, position, speed and acceleration are now automatically determined during the variable motion phases so that the performance is minimized.

By solving this optimal control problem, the variable phases s_var (x, y, z) of the welding process are determined. As a result, in a step S40, those trajectories for the kinematic variables of the variable motion phases that minimize the power consumption of the manipulator process result.

Finally, in a step S50, the entire manipulator process s_ges is defined by the predetermined movement phases and by the variable movement phases and loaded onto the control of the welding robot (not shown).

LIST OF REFERENCE NUMBERS

1 manipulator arrangement

2 workpiece

3 manipulator axis manipulator axis

TCP with glue gun

Klebespur

rectangular auxiliary track

Position constraints

Path in a given phase of movement

Track in variable movement phase

Claims

claims

1. A method for configuring a manipulator process, in particular a robot process, the

at least one predetermined movement phase (9) and

has at least one variable movement phase (10);

wherein a kinematic variable of the manipulator process is predetermined at a transition between one of the predetermined and one of the variable motion phases; and

wherein the kinematic variable in the variable motion phase (10) is automatically specified so that an energy quantity is reduced.

2. The method according to claim 1, characterized in that the manipulator process at least two predetermined movement phases (9), wherein the first predetermined movement phase before a variable movement phase (10) ends and the second predetermined movement phase begins after this variable movement phase (10).

3. The method according to any one of the preceding claims, characterized by a specification of the kinematic size based on a plurality of movement phases (9, 10), in particular of the entire manipulator process.

4. The method according to any one of the preceding claims, characterized in that optionally and / or sections different kinematic variables are specified.

5. The method according to any one of the preceding claims, characterized in that the kinematic variable is predetermined on the basis of minimizing the energy size.

6. The method according to any one of the preceding claims, characterized in that the kinematic variable is a time derivation, in particular a speed and / or an acceleration, at least one axis (3, 4) a manipulator and / or a Manipualtoranordnung for performing the manipulator process.

7. The method according to any one of the preceding claims, characterized in that the kinematic variable on the basis of an extreme size of a time derivative and / or an extreme size of a force and / or torque, is specified.

8. The method according to any one of the preceding claims, characterized in that the kinematic variable on the basis of a compliance, damping, friction and / or inertia to moving axes (3, 4) of the manipulator is specified.

9. The method according to any one of the preceding claims, characterized in that the kinematic variable is predetermined on the basis of at least one regenerative phase of one of at least two energetically coupled manipulators.

10. The method according to any one of the preceding claims, characterized in that the kinematic variable is predetermined based on an energy in an energy storage.

1 1. Configuration means for configuring a manipulator process, characterized in that the means for performing a method according to one of the preceding claims is set up.

A computer program executing a method according to any one of claims when running in a configuration means according to the preceding claim.

A computer program product with program code stored on a machine-readable medium and comprising a computer program according to the preceding claim.