Method for controlling articulated arm with mobile remote control unit spatially remote from articulated arm, and suction excavator

Abstract

The invention relates to a method for controlling an articulated arm with a mobile remote control unit spatially remote from the articulated arm. For this purpose, a machine coordinate system associated with the articulated arm and an input coordinate system associated with the remote control unit are defined. A three-dimensional deviation between the spatial orientation of the input coordinate system and the spatial orientation of the machine coordinate system is then determined. A target movement direction and a target movement speed of an end piece of the articulated arm in an input coordinate system are detected via an operating element of the remote control unit. The target direction of movement is converted into a converted direction of movement using the determined deviation, and the converted direction of movement and the movement speed are transmitted to the articulated arm control unit in order to actuate at least one drive unit of the articulated arm. Furthermore, the invention relates to a suction excavator, which is configured for carrying out the method.

Description

Field of the Invention

[0001] The present invention firstly relates to a method for controlling an articulated arm by means of a mobile remote control unit spatially remote from the articulated arm. Such an articulated arm can be used in different, preferably mobile, working machines, and in particular can be part of a suction excavator, namely as an articulated hose carrier. The present invention thus also relates to a suction excavator with an articulated hose carrier having a remote control unit. Background Art

[0002] A suction excavator relates to a vehicle having a vehicle frame which bears a preferably tiltable material collection container.

[0003] Multi-segmented articulated arms have been used in many machines in order to bring an end piece or end effector (such as a drill bit, a suction socket or a lifting platform) into a specific position and orientation, or to move it along a defined path. The operation of moving the individual segments of the articulated arm by means of the pressure in a control hydraulic cylinder or a similar drive in the vicinity of the machine is difficult for the user to learn and error-prone here. In addition, specific requirements have to be followed, such as holding the end piece in a defined orientation or ensuring an optimal distribution of the crank angles of the individual articulated parts.

[0004] A suction excavator is known from DE 38 37 670 A1, which includes a pneumatic suction nozzle, a collection container for the inhaled soil, and a suction fan connected to the collection container for generating a suction air flow, wherein the suction nozzle opens into the collection container and the soil is separated from the suction air flow in the collection container.

[0005] DE 198 51 111 C1 illustrates a suction excavator having a collection chamber arranged in front in the travel direction and a filter arranged behind in the travel direction in the material collection container.

[0006] In order to guide the suction hose of a suction excavator, two variants have been established, namely a telescopic hose carrier and an articulated hose carrier which represents a special embodiment of an articulated arm. The telescopic hose carrier only partially guides the hose, so that the suction socket (where the material is absorbed) has to be manually guided by the operator. In recent years, therefore, the articulated hose carrier (which is also referred to as a force arm, a guiding arm or an articulated cantilever) has become preferred. It offers the advantages of fully hydraulic guidance and good stability. This enables a more accurate drive control of the working movement without manual power consumption and with the use of a preferably mobile, operator-carriable remote control unit.

[0007] A suction excavator with an articulating boom that can be remotely controlled is known from DE 90 16 448 U1. By means of respective guide rods, the suction head can be controlled to a desired suction position by means of a hydraulic pressure cylinder via a remote control unit.

[0008] A remote control unit and a method for controlling a machine are described in JP 2010-228905 A.

[0009] CN 1 02 561 700 A describes a machine control technology, namely a robotic arm control system and a method and machine therefor. The robotic arm to be controlled consists of at least two segments. The machine includes a drive unit, a remote control unit and an orientation adjustment unit. The control method is set up to use two coordinate systems, where one coordinate system is assigned to the remote control unit and the other coordinate system is assigned to the last segment of the arm. Taking a concrete pump as an example, it is also described how the amount of horizontal torsion between the machine platform of the multi-joint arm and the remote operation unit can be compensated by means of a corresponding measurement of the earth's magnetic field as a common reference direction. As an alternative to the earth's magnetic field, it is proposed to measure two reference points. As long as the two coordinate systems can be associated with a common reference plane, the deviation in the orientation of the two coordinate systems can be calculated. However, it has been shown in practice that ignoring the possible vertical skew between the two coordinate systems, that is, when the two coordinate systems are not in a common reference plane, will lead to incorrect inputs, which may make the control inaccurate.

[0010] DE 10 2016 106 427 A1 describes a method for controlling the movement of an articulating hose carrier having a plurality of segments, wherein an angular change can be effected between adjacent segments by means of a drive. Here, the initial position of the segment is ascertained by means of a sensor, the direction vector and the speed parameter are read, and the target position that the suction crown should occupy at the free end of the last segment is determined. Subsequently, the angular change that has to be effected at the segment in order to reach the target position is determined such that the suction crown moves along a straight-line movement trajectory into the target position. The drive assigned to the segment is actuated in order to effect the predetermined angular change at the segment. The method steps described are repeated cyclically until the direction vector and / or the speed parameter is equal to zero.

[0011] Although the method described in DE 2016 106 427 A1 significantly simplifies the operation of articulated arms, especially articulated hose carriers, in that the user no longer has to directly control a large number of individual drives of the articulated hose carrier, but can, for example, predetermine a direction vector by deflecting a joystick at a remote control unit, and then the control unit converts the direction vector into drive control signals for the individual drives, there is still the difficulty that the operator has to determine this direction vector himself with reference to the position occupied by the suction socket respectively. If the operator is, for example, at an angle of 90° relative to the movement plane of the articulated hose carrier, then the operator has to displace the joystick at right angles to this plane for the displacement to be carried out in this plane of the suction crown, because the direction vector programmed and memorized by the user at the remote control unit does not take into account the position or orientation of the mobile remote control unit. For correct control, this still requires a great deal of practical training and good spatial abstraction ability on the part of the user. In telematics application scenarios, this challenge may be additionally exacerbated due to the operator's free choice of perspective (e.g., from an overhead perspective), zoom (e.g., a thumbnail view for an overview or a magnified view for a more detailed look), and limited field of view (e.g., the limited opening angle of a camera), because the orientation of the reference coordinate systems of the machine control unit and the user input may deviate significantly from each other in all dimensions. Summary of the Invention

[0012] The object of the present invention is to provide, based on DE 10 2016 106 427 A1, an improved method for controlling an articulated arm, especially an articulated hose carrier, using a mobile remote control unit spatially remote from the articulated arm, by means of which the operation is simplified and thus also enables operation by largely unskilled users. In addition, the present invention should also provide a suction excavator for implementing such a method.

[0013] This object is solved by the method according to claim 1 and by the suction excavator according to claim 12.

[0014] A method for controlling a robotic arm using a remote control unit that is spatially remote from the robotic arm first includes the following steps: defining a static machine coordinate system associated with the robotic arm or the machine unit (suction excavator) that carries the robotic arm. As long as the machine unit does not change location, the machine coordinate system is (almost) static during operation. However, the machine coordinate system is typically twisted to any degree relative to the input coordinate system of the remote operating unit and relative to common reference directions such as gravity and the earth's magnetic field. The movement of the robotic arm can be represented, for example, by a vector in the machine coordinate system. In this way, the positioning of at least one end piece at the free end of the robotic arm in the machine coordinate system can be determined, preferably as the end point of a direction vector. For example, at a suction excavator, the suction adapter serves as the end piece; at other units, the end piece can be formed by a tool, a gripper, a pipe fitting, or a similar element that should be positioned at the work site for the work task to be performed.

[0015] In another step, a dynamic input coordinate system associated with the mobile remote control unit is defined. Thus, during operation, there are situations in which the static machine coordinate system of the robotic arm has the same orientation as the dynamic input coordinate system of the remote control unit, but in general, these two coordinate systems do not coincide, so there are deviations in one or more coordinates.

[0016] After defining these two coordinate systems, the deviation between the spatial orientations of the input coordinate system relative to the machine coordinate system is determined. The deviation can be determined, for example, as a deviation vector or a transformation matrix. Thus, the deviation also represents the spatial attitude of the dynamic input coordinate system in the static machine coordinate system, so the static machine coordinate system can also be understood as the superior coordinate system. As an alternative to this, an independent superior world coordinate system can be defined, in which the orientations of the machine coordinate system and the input coordinate system can be determined and related to each other in order to obtain the deviation.

[0017] To cause a controlled movement of the end piece of the robotic arm, the rated movement direction and the rated movement speed of the robotic arm input by the user via the operating elements of the remote control unit are detected in the dynamic input coordinate system, preferably as a rated movement vector. The user, for example, manipulates a joystick at the remote control unit and the sensors of the remote control unit detect the speed and direction of the joystick deflection as the rated movement vector.

[0018] In a subsequent step, the rated speed vector or the rated direction of movement is transformed into the static machine coordinate system taking into account the deviation between the previously determined input coordinate system and the machine coordinate system, in order to generate a transformed movement vector or a transformed direction of movement in the machine coordinate system. This transformation is preferably carried out by means of a computing unit, which can be part of a remote control unit or part of a machine unit comprising an articulated arm. The rated movement speed is only transformed if there is a scaling between the operator's perspective and the on-site situation at the machine. This can occur in the context of telematics applications.

[0019] Finally, the transformed movement vector is transmitted to the articulated arm control unit, which then drives at least one drive unit of the articulated arm in order to move the end piece into the target position predefined by the transformed movement vector. This movement can be effected by driving one, several or all of the drives at the articulated arm. A particularly preferred control of the articulated arm is described in detail in DE 10 2016 106 427 A1, which has been cited above, the relevant content of which is hereby expressly incorporated into the disclosure of the invention described herein.

[0020] Advantageously, the invention takes into account the frequently occurring skew between the coordinate system of the machine (machine coordinate system) and the coordinate system of the remote operating part (input coordinate system). Accordingly, the three-dimensional torsional situation of the machine / vehicle and the remote operating part is comprehensively measured, and an independent reference plane is preferably also determined, for example by evaluating the gravity vector. Compared with the prior art, this results in more robust measures in which the respective reference coordinate systems are preferably corroborated by at least two measuring measures in order to be able to automatically compensate for the torsion between the input coordinate system and the machine coordinate system in advance.

[0021] The method according to the invention also enables the automatic orientation of the end effector by using a three-dimensional reference coordinate system and reduces incorrect inputs, for example when the relationship between the input coordinate system and the machine coordinate system can no longer be clearly understood due to a severe skew between them.

[0022] The articulated arm is preferably an articulated hose carrier, particularly preferably comprising a plurality of load-bearing structural elements, preferably five or six segments (which are also referred to as carrier sections), hydraulic cylinders for driving the individual carrier sections, and a receiving part at the frame of the suction excavator structure. In addition, a pivot drive is advantageously provided for generating the working radius of the articulated hose carrier.

[0023] The suction excavator according to the invention is characterized in that the suction excavator comprises a control unit for controlling the movement of the articulated hose carrier, and the control unit is configured to implement the method according to the invention. Preferably, the material collection container is fastened to the suction excavator such that the material collection container can be emptied. Preferably, the suction excavator implementing the method described for controlling the movement of the articulated hose carrier preferably has sensors at each segment of the articulated hose carrier, and the sensors are directly or indirectly adapted to determine the angles that occur when two adjacent segments move around the joint between them under the action of the assigned drive. Here, the drives are controlled by means of control electronics to obtain adjustment angles that allow the last segment (end piece) or the suction crown or the suction adapter to move freely at least in the X-Y plane, but preferably in a 3D coordinate system, within the scope of so-called inverse kinematics. Here, a change in the positioning of the suction crown representing the end piece is predefined via the control unit in the dynamic input coordinate system of the remote control unit and subsequently converted into the static machine coordinate system of the articulated hose carrier or the suction excavator. In this way, with only one adjustment element (for example, a joystick) and the control input performed at this adjustment element, the operator can bring the suction crown or the end piece of the articulated hose carrier to a predefined position in a targeted and direct path.

[0024] The method according to the invention advantageously allows, by directly inputting preferably as a movement vector in the dynamic input coordinate system of the mobile remote control unit, the positioning of the end piece at a movable articulated arm having any number of segments (each segment rotating one-dimensionally around the joints of the articulated arm) to be controlled.

[0025] The method described here allows the automation of complex operating procedures based on movement inputs performed in the dynamic input coordinate system of the remote control unit, and thereby simplifies the user's operation process. The input for causing the desired movement of the end piece is interpreted in the dynamic input coordinate system of the remote control unit and is thus independent of the relative orientation between the machine and the remote control unit or the positioning and orientation of the user.

[0026] In an advantageous embodiment, when determining the gravity vector In this case, the input coordinate system of the remote control unit is defined, wherein the detected rated movement direction is corrected in order to compensate for the deviation between the attitude of the vertical axis of the remote control unit and the gravity axis. It is crucial to master the gravity vector, preferably the gravity vector in two coordinate systems, so that the input that is expected to be planar on the horizontal plane in the input coordinate system will be correspondingly planar (i.e., orthogonally to the gravity vector) at the machine or the articulated arm even when the input coordinate system (i.e., the remote control unit) is inclined relative to the horizontal line. Therefore, it should be prevented that the end piece moves obliquely upward or downward due to the horizontal input vector only because the remote control unit is inclined at the moment of input. Preferably, the input is adopted only when the remote operating part is inclined by less than 45°, that is, the input can be interpreted and then only the deviated rotation around the gravity axis is considered. For example, the earth's magnetic field can be used as a reference. Therefore, the input vector at the remote control unit is preferably defined taking into account the gravity vector, so that the rated movement direction of the end piece is determined independently of the inclination of the remote control unit relative to the gravity vector, while the rotation of the remote control unit around the gravity axis (also known as the yaw angle in aeronautics) affects the rated movement direction.

[0027] However, for example, in the case of construction site conditions, the measurement of the earth's magnetic field and gravity may be unreliable or even impossible. The earth's magnetic field is easily superimposed by local magnetic fields (such as those from electric motors), and the measurement of gravity is disturbed by local tremors and vibrations. Therefore, in a modified preferred embodiment, a local reference coordinate system with at least three reference points is used. This reference coordinate system can preferably be integrated into construction site furniture, such as construction site fences or the like.

[0028] According to a further embodiment, the rotation in the joints of the end piece can also be leveled by calculation in order to automatically maintain its inclination angle relative to the gravity vector or other reference angles.

[0029] According to an advantageous embodiment, the above method steps are embodied, supplemented and implemented as follows: - Detect the rated movement direction and the rated movement speed (rated movement vector R ) in the dynamic input coordinate system M at the remote control unit; - Transform the thus-defined rated movement vector V I into the static machine coordinate system of the articulated arm ; - Calculate the new target positioning of the end piece in the static machine coordinate system through the predetermined movement time window; - Calculate the spherical coordinates of this target positioning ( , , ); - Perform a binary search on the reference angle based on the current value for reaching a length to at a pre-defined ratio of the joint angle ; - Match the first joint angle to reach the correct polar angle ; - Match the angle with respect to the end piece , in order to ensure an orientation that remains constant in the static Cartesian machine coordinate system of the joint arm or the machine unit carrying the joint arm; - Check the mechanical reachability (valid value range) of all target angles; - When the target angle is invalid, stop or recalculate by a new binary search with the matched angle ratio; - When all target angles are valid, match all joint angles in the control loop by opening the hydraulic valves of the joint arm in proportion to the respective remaining deviations of the target angles (and taking into account the existing pressure if necessary) until all target angles are reached.

[0030] As shown above, for implementing the method according to the invention, it is important to determine the deviation between the static machine coordinate system of the joint arm (machine unit) and the dynamic input coordinate system of the remote control unit and use it when transforming the rated motion vector. Therefore, the accuracy of the control depends on accurately determining the orientation of the two coordinate systems. This can especially lead to some problems under the harsh conditions at the construction site. Therefore, some preferred embodiments of the present invention are shown below, which mention and solve this sub-problem, especially the accurate measurement of the remote control unit, the positioning and orientation of the end piece, and the positions or occupied angles of the respective joints of the joint arm.

[0031] In order to detect the measured values, various, per se known 3D measurement systems can generally be used to detect the required data at a high frequency. However, some additional limitations must be taken into account when using construction machinery at the construction site, such as: - If there are too many interference noises and variable sound reflectors, the ultrasonic-based system works less reliably; - The electromagnetic system is interfered by the metal housing of the construction machinery and the electric motor; - The radio-based system and radar are inaccurate and are interfered by local high dynamics; - Optical systems are easily overexposed by sunlight (and also infrared light), and passively illuminated markers are more robust in this regard; - Optical systems are generally affected by dust and visual obstructions caused by moving structural elements, tools, and machines; in the dark, they require artificial lighting; - Mechanical measurement systems are generally prone to failure at movable parts, but especially in the surrounding environment with strong environmental impacts; - Inertial sensors are disturbed by the vibrations of machine units when measuring acceleration (e.g., when detecting the gravity vector), and the measurement of the Earth's magnetic field may be disturbed by local electromagnetic fields, such as those from electric motors.

[0032] To overcome the described difficulties and limitations, various solutions are listed below, which can be used individually or in combination within the scope of the present invention. They thus represent preferred embodiments that can be used especially in the suction excavator according to the present invention.

[0033] Preferably, various measurement systems are used to detect the orientation related to the orientation of the input coordinate system and the machine coordinate system, especially optical measurement systems that can detect passively or actively illuminated markers; inertial sensors that can determine the gravity vector and the Earth's magnetic field. Manual adjustment of the relative orientation by the operator can also be implemented.

[0034] Preferably, to define the input coordinate system, the relative rotation around the gravity axes of the input coordinate system and the machine coordinate system is derived from the positioning measurements of at least two points. For this purpose, an optical system based on passively illuminated markers in the visible spectrum or a laser-based positioning measurement system is preferably used. These systems are called "beacons"; this refers to an inward-outward positioning and tracking system based on lasers. These systems are described, for example, in US 10 338 186 B2. Although they use active light (mostly infrared light), in pulsed lasers, the active light can be made bright enough to stand out as a signal from sunlight. However, high-energy lasers also pose a risk of dazzling people standing nearby. For reasons of operational safety and cost, a particularly preferred variant is to combine passively illuminated markers in the visible spectrum with a high-resolution camera.

[0035] In addition, the camera can be placed at the machine unit (e.g., suction excavator) carrying the articulated arm, on a tripod, at construction site furniture (e.g., fence), and / or at the remote control unit. However, a single camera does not provide depth information. Therefore, a high-performance stereo camera can be preferably installed on a tripod and / or on the vehicle.

[0036] In particular, a camera can be installed at the remote control unit at little cost and can be easily cleaned. Robust detection of 3D information can be achieved by movement here, while the components to be captured (machine unit, articulated arm segments, and end piece) remain stationary. Therefore, the use of an optical 3D measurement system is particularly suitable for the rather rare comparative measurements used to calibrate other measurements.

[0037] A mechanical measurement system is provided because the articulated arm already provides the mechanical basic structure and the articulated arm is also implemented firmly enough for use in harsh construction sites. The measurement of the angle between the individual articulated segments can be achieved mechanically or by using inertial sensors. However, the latter may be disturbed by vibrations at the machine unit. These disturbances can be corrected by corresponding low-pass filters, but this is accompanied by a reduction in the achievable acquisition frequency and thus an interference with the control loop for reducing the angular error for the positioning of the end piece. When using inertial sensors, the inclination of the entire machine unit must also be noted in order to derive the correct crank angles of the articulated arm segments from the measured gravity vector.

[0038] A preferred embodiment uses a mechanical rotation angle sensor. A modified embodiment uses a hydraulic cylinder with a linear position sensor at the articulated arm to determine the position of the individual articulated arms. The deflection of the hydraulic mechanism can also be used to derive the resulting crank angles between the articulated arm segments by taking into account the mechanical geometry.

[0039] Potential errors from high-frequency mechanical measurements can be identified and corrected by low-frequency measurements using inertial sensors. Therefore, preferably, high-frequency and low-frequency measurements are combined with each other. In addition, preferably, optical measurements of passively illuminated markers by a camera, preferably in the remote control unit, can also be introduced (at an even lower frequency), especially for periodic calibration of the entire system. Continuous optical tracking of the end piece can be carried out additionally at particularly sensitive or critical moments.

[0040] In a modified embodiment, one or more cameras in the remote control unit can measure the relative orientation of the remote control unit relative to the end piece of the articulated arm and / or relative to the vehicle (suction excavator).

[0041] The remote control unit can preferably also be equipped with 3D inertial sensors (IMUs) like the entire machine and the end piece. In addition, the measurement of the earth's magnetic field is also important for the correct interpretation of the movement input. In order to quickly identify disturbances and the resulting errors, the values of multiple IMUs at positions that are as far apart as possible but mechanically firmly coupled can be compared with each other.

[0042] Preferably, the proposed automatic transformation from the input coordinate system to the machine coordinate system is used only when the measurement of the common reference coordinate system is corroborated by at least two independent measurement systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Further details, advantages and improvements of the present invention result from the following description of preferred embodiments with reference to the accompanying drawings. In the figures:

[0044] Figure 1 A symbolic illustration of a suction excavator is shown, which is operated by a user with a remote control unit at a construction site;

[0045] Figure 2 A first symbolic illustration of an articulated arm and a remote control unit for implementing a method for controlling the articulated arm according to the present invention is shown;

[0046] Figure 3 A second symbolic illustration of the articulated arm is shown to clarify the positioning of the end piece relative to the root joint;

[0047] Figure 4 A diagram showing a possible relationship between the dynamic input coordinate system of the remote control unit and the static machine coordinate system of the articulated arm with the positioning of the end piece is shown;

[0048] Figure 5 A flow chart of a flow chain for calculating all the angles of the articulated arm from a rated motion vector in the dynamic input coordinate system is shown;

[0049] Figure 6 A third symbolic illustration of the articulated arm is shown to clarify the division of the angles between the segments of the articulated arm;

[0050] Figure 7 A chain diagram for calculating a vector of a certain point and the distance between the point and the root joint is shown. DETAILED DESCRIPTION OF THE INVENTION

[0051] Figure 1 A typical application situation is explained, in which a suction excavator 10 with an articulated arm 01 is used at a construction site. The static machine coordinate system of the suction excavator 10 , the end effector coordinate system of the end effector 04 and the dynamic input coordinate system of the remote control unit 02 are three-dimensionally twisted relative to each other and also deviate from the world coordinate system based on the gravity vector and the earth's magnetic field. Alternative reference coordinate systems can be obtained by measuring three reference points P installed, for example, at construction site furniture such as a construction site fence, 1 P2 , P 3 is implemented.

[0052] Figure 2 shows the articulated arm 01 as a schematic diagram. The articulated arm is an articulated hose carrier of a suction excavator ( Figure 1 ) in the following exemplary embodiment. The articulated arm 01 has a plurality of articulated arm segments L n , and these articulated arm segments are respectively connected to each other by joints J n . A remote control unit 02 is provided separately and spatially separated from the articulated arm 01. The user 03 can use the remote control unit to control the desired movement of the articulated arm 01. In a telematics application, the remote control unit can also be located outside the field of view and the direct working range, that is, at an arbitrarily far distance.

[0053] The remote control unit 02 and the articulated arm control unit (not shown) cooperate to implement the method for controlling the articulated arm according to the present invention. Here, the ultimate goal is to move the end effector 04 (which is also referred to as the end piece) located at the free end of the articulated arm 01 to a desired target position in order to complete the operation task there. In a suction excavator, the operation task usually consists of absorbing materials, such as excavated soil, by means of the negative pressure generated by the fan unit of the suction excavator, and transporting the materials to a material collection container through the suction hose carried by the articulated arm.

[0054] In Figure 1 , Figure 2 , Figure 3 , Figure 6 , Figure 7 , coordinate system symbols are respectively drawn for easier understanding. Among them, the coordinate system symbol without an arrow only represents the orientation but does not represent the relevant position.

[0055] The articulated arm segment L n rotates around the joint J n . The orientation of the articulated arm 01 is mapped in the static machine coordinate system , and the orientation of the remote control unit 02 is defined in the dynamic input coordinate system .

[0056] Figure 3 Also shows the principle structure of the articulated arm 01 according to Figure 2 . The angular range drawn here is mainly used to represent the position of the end piece 04. The end piece 04 is installed at the last joint J E and can also be understood as an end effector, and its position is at the last joint J E . The movement of the position of the end effector is inFigure 3 with respect to the root joint J 0 or also with respect to the first joint J 1 in spherical coordinates ([[]] , , ), it is shown that the first joint at the suction excavator with respect to the root joint J 0 can only rotate about the Z-axis (no angular change between J 0 and J 1 ). The following explanations for presenting the method also relate to this type of illustration.

[0057] In order to functionally implement a method for controlling the articulated arm in an embodiment of the articulated hose carrier of a suction excavator, the following assumptions are made:

[0058] a) The articulated arm 01 consists only of one-dimensional rotary joints J n , where all joints J 1 to J n are oriented consistently and can only be additionally rotated with a 90°-rotating axis at the root joint J 0 or J 1 .

[0059] b) The movement of the end effector with respect to the root joint J 0 or J 1 can be defined in spherical coordinates ([[]] , , ), where the azimuth angle is determined only by the angle of the root joint J 0 at the suspension of the arm, and the angles 1 to J i of all other joints collectively determine the length (or spherical radius ) and the polar angle (see Figure 3 ).

[0060] c) The ratio of the individual joint angles to is pre-defined by weights and offsets (e.g., evenly distributed) such that the radius , i.e., the positioning of the end effector relative to the root joint J 1 can be determined by specifying a reference angle : Among them, hereinafter starting from the equal distribution of the angle to means that: And .

[0061] d) Input coordinate system of the remote control unit and the machine coordinate system are jointly defined in the superior coordinate system (here the world coordinate system ), see Figure 4 a). Alternatively, it can also be defined in ( ( Figure 4 b) or defined in ( ( Figure 4 c). In addition, the positioning of the end effector must be defined in the machine coordinate system . The following description is based on the spatial structure ( Figure 4 a). It does not have to have an original positioning here. A reference frame is sufficient to orient, for example, by means of gravity and the north pole of the earth's magnetic field (see Figure 2 or Figure 3 ). Alternatively, the reference coordinate system can be determined by measuring at least three reference points (see Figure 1 P in 1 to P 3 ).

[0062] Figure 4 Shows the possible relationship between the positioning of the end effector associated with the input coordinate system and the machine coordinate system .

[0063] As already explained above, at least one drive unit of the articulated arm 01 can be driven by a control unit known per se to move the end piece 04 or the end effector to the target positioning predetermined by the transformed motion sector, as described in DE 10 2016 106 427 A1. Such a control unit can also be called an inverse kinematics mechanism because it always drives each joint according to the target positioning of the end piece. The possible technical implementation of such an inverse kinematics mechanism at the articulated hose carrier of a suction excavator can be as follows:

[0064] 1. First, algorithmically process the control instructions of the remote control unit to indirectly manipulate the oil pressure in the hydraulic cylinder to move the articulated arm segments, thereby causing the controlled movement of the end effector.

[0065] 2. The articulated arm consists only of one-dimensional rotary joints, where all joints are oriented identically and only the root joint J 0 has a rotational axis with a 90° rotation.

[0066] 3. The movement of the articulated arm can be defined in spherical coordinates, where the azimuth angle is determined only by the angle of the root joint J 0 at the suspension of the arm, and the angles of all the other joints J n together determine the length (or the spherical radius ) and the polar angle .

[0067] 4. The ratio of the respective joint angles is pre-defined (e.g., evenly distributed), so that the desired arm length can be determined by specifying the respective angle values .

[0068] 5. The angles of the articulated arm segments are detected simultaneously using different sensors and measurement measures in order to eliminate the corresponding systematic measurement errors. This is preferably two or more of the following sensors: a. Rotary angle sensors in the joints of a multi-segment articulated arm; b. Linear position sensors in hydraulic cylinders; c. Inertial sensors for measuring the gravity vector; d. Camera- or laser-based sensors for absolute measurement of the position or orientation of the individual articulated arm segments, including the end effector, relative to an external measurement station, where the external measurement station is for example: i. At a machine, ii. Mobile on a tripod or integrated into construction site furniture, such as a fence, iii. Mobile at a remote control unit.

[0069] 6. The relative orientation of the articulated arm and the remote control unit is detected by a sensor combination in order to also eliminate systematic measurement errors in this regard. Preferred in this context are: a. 3D inertial sensors in or at the remote control unit and at the articulated arm; b. Redundant 3D inertial sensors with as large a spacing as possible and immovable mechanical connections in order to identify and evaluate the disturbing influence of local magnetic fields on the electronic compass. c. Camera- or laser-based sensors for absolute measurement of the orientation of the remote control unit, the articulated arm and the end effector relative to each other or relative to an external measurement station, where the external measurement station is for example: i. At the machine, ii. Movable on a tripod or integrated into construction site furniture, such as in a fence, iii. Movable at the remote control unit.

[0070] 7. Detect the positioning of the end effector simultaneously with two measurement methods in order to identify systematic measurement errors. Preferably in this regard: a. Mechanical measurement of the end effector based on the orientation of all segments of the articulated arm; b. Camera - or laser - based sensors for absolute measurement of the orientation of the remote control unit, the articulated arm, and the end effector relative to each other or relative to an external measurement station, the external measurement station such as: i. At the machine, ii. Movable on a tripod or integrated into construction site furniture, such as in a fence, iii. Movable at the remote control unit.

[0071] Figure 5 Shows a flowchart of the process chain for calculating all the angles of the articulated arm 01 based on the nominal motion vector in the input coordinate system detected at the remote control unit 02. The flow of the control instructions of the remote control unit 02 proceeds in the order shown in in order to obtain all the target angles Figure 5 of the joint J n so as to cause a controlled movement of the end effector along the transformed motion vector Here, the nominal motion vector is transformed into the transformed motion vector using the previously determined deviation between the input coordinate system and the machine coordinate system Next, a feasible solution for this transformation is explained in detail for the case of mapping and and in a common reference coordinate system (see Figure 4 a):

[0072] I. Levelling (optional): The nominal motion vector is given in the input coordinate system of the remote control unit. Before transforming (transforming) into the machine coordinate system , the input coordinate system is levelled according to the previously known gravity vector before the transformation into the machine coordinate system Orientation or leveling is performed so that only the rotation of the remote control unit 02 about the gravity axis needs to be considered. For this purpose, a new leveled input coordinate system is constructed in the following sub-steps :

[0073] 1. First, check whether the input coordinate system is tilted by less than 90° relative to the gravity vector , that is, whether the scalar product of the unit vector along the z-axis of the input coordinate system and the reciprocal of the normalized gravity vector in the common world coordinate system is less than zero, that is, whether they point in different directions: (assuming that has been defined in the world coordinate system ) Otherwise, the remote control unit is in a downward skewed state and the input vector cannot be clearly interpreted. In this case, the control of the articulated arm should be interrupted.

[0074] 2. When the prerequisite is met, the axes of the leveled input coordinate system are constructed by calculating the cross product between the x-axis or y-axis of the input coordinate system and the gravity vector (in the common world coordinate system ). Here, the y-axis, that is, the unit vector along the y-axis, is taken as an example.

[0075] 3. In order to level the rated motion vector correspondingly, this rated motion vector is simply expressed with consistent values in the leveled input coordinate system .

[0076] II. Input transformation: The input vector or the leveled input vector can now be expressed in the machine coordinate system by the following calculation rules:

[0077] III. New target positioning: If the current positioning of the end effector is taken as a point in the machine coordinate system Given that, the new target position can be calculated by moving along the transformed motion vector in the machine coordinate system .

[0078] IV. Spherical coordinates: Convert the target position of the end effector into spherical coordinates

[0079] Pay attention to the orientation of the machine coordinate system here and shift the resulting angular values by multiples if necessary . Alternatively, all three values of the spherical coordinates can also be obtained through vector calculations. Here, the radius or the target position from the root joint is the length of the vector between the two points

[0080] The pivot angle is the scalar product of the unit vector along the reference axis in the machine coordinate system (e.g., the x-axis in Figure 2 and 3 ) and the normalized projection of onto the horizontal plane of the machine coordinate system (e.g., the x / y plane in and Figure 2 and 3 ). To project onto the desired plane, the vector components of the dimension to be ignored (e.g., z) can be set to zero. The projection can be recorded through the cross product, for example:

[0081] is the scalar product of the unit vector along the reference axis in the machine coordinate system (e.g., Figure 2 and 3 the z-axis in ) and the normalized vector in the machine coordinate system

[0082] The pivot angle has been given as the result of this method step:

[0083] If​ , then the vector divides the angle into and and divides into and (see Figure 6 ). Where applicable:

[0084] V. 2D Inverse Kinematics: The calculation of the angles to can be solved in a two-dimensional coordinate system because all the joints to are in the same plane and rotate about parallel axes. The magnitudes of the angles to together with the lengths of the existing segments to define the length of the vector . Search for the angles to . Where applicable:

[0085] The solution of the analysis only exists in special cases. The following possible solution approaches are presented as general solution approaches for variations in the ratio of almost any number of segments, angles to and the different lengths of the existing segments to :

[0086] 1. The geometric relationships of the length-related segments to are expressed in an independent 2D coordinate system, where is oriented along the x-axis (because has no effect on the vector length ; see Figure 6 and Figure 7 ).

[0087] 2. Each of the length-related segments to is now expressed as a 2D vector in this coordinate system and rotated by by (see Figure 7 ). For the following applies because Oriented along the x-axis. The vectors are calculated respectively as follows to using to as the lengths of segments to :

[0088] 3. Points to are generated from the resulting 2D vectors (see Figure 7 ).

[0089] 4. Now, the matching values should be found such that the spacing corresponds to the target spacing . All values are defined by a common reference angle because and differ from only due to a predefined weight and offset .

[0090] The binary search algorithm is used to search for the matching . In addition to the global parameter limits and , local limits and are also considered here. When necessary, the local weight and offset can optimize the movement range of the entire articulated arm.

[0091] 5. Now, considering the local weight and offset , the searched Values are derived for all to angle values. It consists of the and already found during the transformation to spherical coordinates in step IV. is the angle, i.e., the scalar product between the normalized vector and the unit vector along the x-axis of the auxiliary coordinate system used here:

[0092] VI. Orienting the end piece: To calculate the last remaining angle , after knowing and the individual vectors to it is already possible to calculate part of it:

[0093] can be described as and the scalar product of the vector in the target orientation of the last segment. Since the latter is defined relative to a vector in the reference coordinate system, for example relative to the gravity vector , we use its normalized representative in the machine coordinate system as a reference:

[0094] Immediately afterwards, the desired deviation of the orientation of from the gravity vector can be directly calculated using the known angle .

[0095] Figure 6 shows the division from to and and by the vector to and and The length of the vector is determined by the length of the segment and the included angles .

[0096] Figure 7 shows the chain of vectors to for calculating the point and its distance from the root joint .

[0097] List of Reference Signs

[0098] 01 – Articulated Arm / Articulated Hose Carrier

[0099] 02 – Remote Control Unit

[0100] 03 – User

[0101] 04 – End Effector

[0102] L n – Articulated Arm Segment

[0103] J n – Joint

[0104] P E – Positioning of End Effector

[0105] P 1 、P 2 、P 3 – Reference Point

[0106] M I – Input Coordinate System

[0107] M M – Machine Coordinate System

[0108] M E – End Effector Coordinate System

[0109] M W – World Coordinate System

[0110] – Transformed Motion Vector

[0111] – Rated Motion Vector

Claims

1. A method for controlling a robotic arm (01) using a mobile remote control unit (02) spatially remote from the robotic arm, the method comprising the following steps: - Define a machine coordinate system (M) associated with the articulated arm W ), so as to be able to determine the positioning of at least one end piece (04) at the free end of the articulated arm in the machine coordinate system; - Define an input coordinate system (M) associated with the remote control unit (02) I ) - determining a three-dimensional deviation between the 3D spatial orientation of the input coordinate system and the 3D spatial orientation of the machine coordinate system; - detecting the rated movement direction and rated movement speed of the end effector (04) of the robotic arm input via an operating element of the remote control unit (02) in the input coordinate system; - Transform the rated movement direction into a transformed movement direction in the case of using a 3D deviation between the determined input coordinate system (M I ) and the machine coordinate system (M M ). - transmitting the transformed movement direction and the movement speed to a robotic arm control unit and driving at least one drive unit of the robotic arm to move the end effector (04) to a predetermined target position.

2. The method according to claim 1, wherein, the input coordinate system of the remote control unit is defined in the case of determining a reference plane, wherein the detected rated movement direction is corrected in order to compensate for the deviation between the attitude of the vertical axis of the remote control unit and a reference axis erected on the reference plane.

3. The method according to claim 2, wherein, the reference plane is determined based on the gravity vector, wherein the detected rated movement direction is corrected in order to compensate for the deviation between the attitude of the vertical axis of the remote control unit and the gravity axis.

4. The method according to any one of claims 1 to 3, wherein, the rated movement direction and rated movement speed of the end effector are detected as a rated movement vector in the input coordinate system; and the rated movement vector is transformed into a transformed movement vector using the determined deviation between the input coordinate system and the machine coordinate system; and the transformed movement vector is transmitted to the robotic arm control unit.

5. The method according to claim 4, wherein, the spherical coordinates of the target position are calculated based on the transformed movement vector in the machine coordinate system.

6. The method according to any one of claims 1 to 5, wherein, the transformation from the input coordinate system to the machine coordinate system is only carried out taking into account the determined three-dimensional deviation if the three-dimensional deviation of the 3D spatial orientation of the input coordinate system relative to the 3D spatial orientation of the machine coordinate system is corroborated by measurements using at least two independent measurement systems.

7. The method according to any one of claims 1 to 6, wherein, in order to define the input coordinate system, preferably the orientation of the input coordinate system related to the machine coordinate system is measured using one or more measurement systems from the following list: - an optical measurement system capable of detecting passively or actively illuminated markers; - an inertial sensor capable of determining the gravity vector and the earth's magnetic field.

8. The method according to any one of claims 1 to 6, wherein, in order to define the input coordinate system, preferably the relative rotation about the gravity axes of the input coordinate system and the machine coordinate system is derived from the positioning measurements of at least three points using one or more measurement systems from the following list: - A laser-based positioning measurement system preferably with pulsed light; - An optical measurement system capable of detecting passively or actively illuminated markers; - A stereo camera preferably arranged at the machine unit carrying the articulated arm or at stationary construction site furniture; - One or more cameras arranged at the remote control unit or at stationary construction site furniture.

9. The method according to any one of claims 1 to 8, characterized in that in order to determine the positioning of the end piece, a positioning measurement is preferably carried out using one or more measurement systems from the following list: - An optical measurement system capable of detecting passively or actively illuminated markers; - A laser-based positioning measurement system preferably with pulsed light; - A stereo camera preferably arranged at the machine unit carrying the articulated arm; - One or more cameras arranged at the remote control unit; - A mechanical measurement system preferably with rotational angle sensors at the articulated arm; - Inertial sensors at the joints of the articulated arm and / or at the remote control unit.

10. The method according to any one of claims 1 to 9, characterized in that in order to define the input coordinate system and the machine coordinate system, the earth's magnetic field is measured and taken into account.

11. The method according to any one of claims 1 to 10, characterized in that the articulated arm is a component of one of the following devices: · Suction excavator; · Concrete pump; · Channel cleaning machine; · Channel inspection machine; · Drill; · Lift table.

12. A suction excavator having a vehicle frame, a blower unit for generating a suction flow for absorbing material, a filter unit, a material collection container for collecting the absorbed material, a multi-segmented articulated hose carrier, and a mobile remote control unit for controlling the movement of the articulated hose carrier, characterized in that the control unit of the suction excavator and the remote control unit are configured to carry out the method according to any one of claims 1 to 11.

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