Method for operating an electric motor, electrical control or evaluation device therefor, and machine equipped therewith

Abstract

The invention relates to a method for position-monitored and / or safe operation of an electric motor (9). In this method, the rotational angular positions of the motor's (9) rotor are detected by means of a physical rotational angular position detection device (11). Furthermore, the rotational angular positions of the motor's (9) rotor are calculated by means of a rotational angular position calculation device (17). This rotational angular position calculation device (17) is configured to calculate the respective rotational angular positions based on the electrical voltages (18) supplied to the motor (9) and / or based on the electrical voltages (18) applied to the motor (9), as well as based on the motor currents (19) received by the motor (9) and / or the motor currents (19) supplied to the motor (9).Furthermore, the rotational angle positions detected by the rotational angle position detection device (11) and the rotational angle positions calculated by the rotational angle position calculation device (17) are compared at the same time by means of a control or evaluation device (3, 3', 3''). The control or evaluation device (3, 3', 3'') outputs or provides at least one control or evaluation signal (21) which includes at least one piece of information regarding the equality and / or extent of deviation between the detected and calculated rotational angle positions. In addition, an informative warning is issued and / or the further operation of the motor (9) is stopped and / or a safe operating state is established for a machine or machine component driven by the motor (9) if a predetermined extent of deviation has been reached or exceeded.Furthermore, a corresponding control or evaluation device (3, 3', 3'') and a corresponding machine are specified.

Description

[0001] The invention relates to a method for position-monitored or safe operation of an electric motor, an electrical control or evaluation device for controlling an electric motor, and a machine comprising at least one electric motor for performing machine movements as specified in the claims.

[0002] To increase the fault tolerance of electronically controlled systems, such as industrial robots or other machines, it is known to acquire control-relevant system states, such as current positions, using two channels and, if necessary, diverse technologies. By comparing the acquisition channels, it can be deduced whether the acquisition system or the technical system is operating as intended or whether a technical fault has potentially occurred. This allows for the achievement of so-called single-fault tolerance and raises the safety level of technical systems. For example, WO2020 / 087099A1, which originates from the applicant, addresses the criterion of single-fault tolerance for electronically controlled systems. Achieving single-fault tolerance is always associated with increased technical effort and, consequently, higher costs.

[0003] The object of the present invention was to overcome the disadvantages of the prior art and to provide devices or methods with which the safety of controlled technical systems can be increased and which can also be implemented as cost-effectively as possible.

[0004] This task is solved by the subject matter of the independent claims. Advantageous further developments can be found in the dependent claims.

[0005] The method according to the invention serves for the position-monitored or safe operation of an electric motor. This method comprises the steps of: - detecting the rotational angular positions of the motor's rotor by means of a physical or sensory rotational angular position detection device, in particular by means of a so-called encoder or electromechanical rotary angle sensor; - Calculation of rotational angular positions of the motor rotor using a rotational angular position calculation device, in particular the computational determination of the respective rotational angular positions of the motor rotor without the use of a physical rotational angle sensor or speed sensor, which rotational angular position calculation device is designed for this purpose, (i) based on electrical voltages supplied to the motor and / or based on electrical voltages applied to the motor, as well as (ii) to calculate the respective rotational angular positions based on motor currents absorbed by the motor and / or motor currents supplied to the motor, in particular to determine them purely computationally; - Comparing the rotation angle positions detected by the rotation angle position detection device and the rotation angle positions calculated by the rotation angle position calculation device at the same or corresponding times using a control or evaluation device; - Output or provision of at least one control or evaluation signal by means of the control or evaluation device, which control or evaluation signal includes at least one piece of information regarding equality and / or extent of deviation between detected and calculated rotation angle positions; - Issuing an informative warning message and / or stopping further operation of the motor and / or establishing a safe operating condition for a machine or machine component driven by the motor when a predetermined deviation level is reached or exceeded.

[0006] The measures according to the invention enable single-fault safety to be achieved or to approach the requirements for single-fault safety. Consequently, increased safety for persons and property in connection with potentially hazardous activations or movements of the motor can be achieved. In particular, deviations between the planned and actual position of the motor or the coupled axis of motion or drive unit can be reliably determined, especially with single-fault safety. Accordingly, the safety of automated or semi-automated or control-controlled systems or installations can be increased with the specified measures.

[0007] Furthermore, the measures according to the invention enable a relatively cost-effective increase in the safety level of existing systems, such as industrial robots, with single-channel or non-diversitary rotary encoders or position encoders. In particular, the measures described allow for a relatively simple and reliable safety upgrade. A further advantage is that the measures described enable efficient retrofitting of existing systems, such as industrial robots, with single-channel or non-diversitary rotary encoders or position encoders.

[0008] Furthermore, the corresponding plausibility check of the states or positions of the motor can be implemented with minimal delay, especially in real time.

[0009] Furthermore, the measures according to the invention make it possible to achieve a saving in the required installation space of the motor, thereby enabling the creation of more compact drive units. This is primarily due to the elimination of a second, potentially technically diverse, rotary encoder. Wiring costs can also be minimized.

[0010] Furthermore, the reduced mechanical and electrical complexity of the motor or drive unit can decrease the required maintenance effort. It may also be possible to extend the recommended maintenance interval under certain circumstances.

[0011] The electrical voltages supplied to the motor refer to the active voltage supply provided by an electrical drive controller. The electrical voltages applied to the motor refer to any regenerative effects of the motor. The motor currents drawn by the motor and the motor currents supplied to the motor refer to currents that can be influenced by the drive controller or its current regulator. The solution according to the invention can be particularly advantageous when the motor functions as a servo motor. The rotational angular positions of the rotor can also be referred to as the rotor bearing angle or rotor angle.

[0012] Naturally, the definition "at the same time" includes deviations due to control engineering or performance-related tolerances. The essential point is that the comparison of values ​​or results between the physical rotary angle position detection device and the computational or sensorless rotary angle position calculation device refers to at least approximately the same observation time relative to the motor.

[0013] The following describes embodiments of the invention, noting that these embodiments can generally relate to both the method and further implementation forms (control or evaluation device, machine, etc.). In particular, features of the method can also be implemented in the respective devices and vice versa.

[0014] According to one embodiment, it can be advantageous to calculate the rotor's angular positions based on the motor voltages and currents, i.e., to determine them without using a rotary encoder, by feeding the motor voltages and currents as inputs to a Kalman filter (KMF), in particular an extended Kalman filter (EKMF), wherein the Kalman filter comprises a mathematical description or virtual model of the motor. In particular, the Kalman filter can be configured to represent or process a mathematical or computational model of the motor to be observed or controlled. With a Kalman filter, especially an extended Kalman filter, it is advantageously possible to determine states of interest or parameters of physical systems that are difficult to ascertain with sufficient accuracy, even if they cannot be measured directly or only with significant noise.For the system, which could be an electric motor in particular, a mathematical description is required that is linearizable, at least for a small period of time, and can be described in a discrete-time manner for implementation in a computing unit. Under these circumstances, it is also possible to describe nonlinear, time-varying physical systems. In particular, for the purpose of position determination without an electromechanical sensor, it is possible to model an electric machine (e.g., a PMSM synchronous machine) with sufficient accuracy.

[0015] Furthermore, the rotation angle position calculation device, in particular a Kalman filter, can incorporate operating point-dependent inductance values, especially differential inductances, into a model, particularly by describing its operating point as a function of currents, positions, and / or torque. This allows the rotation angle positions of the rotor to be derived more accurately and precisely at each operating point. The aforementioned measures enable a relatively accurate and reliable determination of the rotor's rotation angle without requiring a physical, for example, electromechanically constructed, rotation angle position sensor.

[0016] According to an advantageous implementation measure, a test signal can be applied to the motor, allowing inductance differences, preferably caused by iron saturation effects, to be clearly observed via the measured currents and applied voltages of the motor. "Observed" here means that asymmetries in the motor's inductances can be evaluated by the rotation angle / position calculation device in such a way that the respective rotation angle positions of the rotor, i.e., the respective rotor angle positions, can be determined via an algorithm. This enables a fail-safe and cost-effective speed and position control of the motor's rotor without the use of a second physical position or rotation angle encoder. For relatively accurate orFor a relatively reliable computational determination of the rotational angle positions of the rotor, it is advantageous if there is a sufficient difference between the differential d-inductances L. d and q-inductances L q The engine's operating point range must be sufficiently wide. Previous studies show that this should often be greater than 15%.

[0017] As a suitable measure, the speed and / or position control of the motor can preferably be based exclusively on the values ​​or angular positions of the physical angular position sensing device, for example, an encoder, because the angular position sensing device is comparatively more accurate. The values ​​or angular positions calculated or estimated by the angular position calculation device, on the other hand, are advantageously used to control the motor with higher reliability, in particular to increase the safety level of the control or evaluation device.

[0018] Another advantageous configuration allows for the comparison of the determined rotation angle positions from the physical rotation angle position detection device and the calculated rotation angle positions from the rotation angle position calculation device to be performed at a time when the motor is stationary, specifically when the motor is in a standstill controlled by a motor controller or in a braked standstill. This allows conclusions to be drawn about the system's intended function, particularly that of the physical rotation angle position detection device, if the comparison shows that both rotation angle positions remain constant or show no change over a predetermined period. This is especially true because both status or information sources deliver the same result or identical information: "standstill."

[0019] According to a further development, it is possible to determine the inductance values ​​of the motor by applying a time-varying voltage signal to the motor, preferably while it is at rest. q and with a time-varying voltage signal u d is actuated, based on which the respective profiles of the motor currents i q and i d The inductance values ​​L are measured, and based on these measurements, the following values ​​are determined. q and L d The inductance values ​​L can be calculated. q and L d The mathematical description of the motor is stored in a data model, and the rotation angle position calculation device is provided for subsequent calculations of the rotation angle positions of the motor's rotor. This allows the relevant motor parameters to be comprehensively recorded and used for subsequent calculations of the respective rotation angle positions of the motor.

[0020] According to a further advantageous embodiment, it can be provided that, as a result of a finding that determined inductance values ​​L q and L d The motor has not achieved a predetermined minimum difference at individual rotor positions, by imprinting an additive displacement signal which changes the magnetic operating point, for example by imprinting an additional current, in particular a d-current, such that a predetermined minimum difference between the inductance values ​​L is achieved. q and L d , which predetermined minimum difference enables a reliable calculation of the rotor's angular positions. This ensures seamless and reliable calculation of the rotor's respective angular positions. The changes in the voltage signal u q (q-voltage) and / or in the voltage signal u d(d-voltage) or the injection of the additive displacement signal does place an additional load on the motor, causing it to heat up. However, this also ensures a comprehensive and sufficiently accurate calculation of the respective rotational angular positions of the rotor.

[0021] Furthermore, it can be advantageous to supply the motor with a time-varying test signal, in particular a noise signal, a high-frequency sine wave, or another signal form. This is especially true for low speeds or in ranges where the motor moves only imperceptibly. Using the resulting test currents and the supplied test signal, the current position of the rotor, particularly its angular position relative to the stator, is calculated by the rotation-angle-position calculation device, especially with the use of a Kalman filter. These measures make it possible to determine the rotor's position even when stationary, e.g., in braked motors, or near stationary, e.g., in motors controlled to standstill.By comparing the position information with the physical rotation angle position detection device, a reliable determination of the actual or highly probable standstill positions of the rotor can be achieved even during temporary standstill states of the motor.

[0022] According to an advantageous embodiment, it can also be provided that, in an active operating and movement state of the motor, a time-varying test signal is supplied which is variable with respect to the motor's rotational speed, in particular a noise signal, a high-frequency sine wave signal, or another signal form, and wherein the respective rotational angular positions of the rotor, in particular the respective angular positions of the rotor relative to the stator, are calculated by means of the resulting test currents and the supplied test signal using the rotational angle-position calculation device, in particular using a Kalman filter. It is particularly advantageous here to provide this time-varying test signal in the lower speed range of the motor, e.g., in the range from 0 to an application-specific maximum speed, which is in any case below the rated speed.This value can be up to 50%, preferably up to 30%, and particularly preferably up to 20% of the motor's rated speed. Furthermore, it can be advantageous if the magnitude of the test signal changes depending on the motor's speed and, in particular, decreases with increasing speed. This allows for more accurate results regarding the angle-of-rotation position measurement, even at low motor speeds. An undesirable additional electromagnetic torque in the motor can be minimized by ensuring that the test signal acts primarily as a d-voltage, but not as a q-voltage.

[0023] Furthermore, it can be provided that, in a first step, a rotor rotation of at least 360° is performed and the determined rotational angle positions are stored in a memory. In a second step, a coincidence check is performed in which the currently determined rotational angle positions are checked against the rotational angle positions stored in the memory for coincidence. Such a test routine allows for a rapid yet thorough verification of the system's intended and proper functioning at any time, particularly of the computational and physical information sources, i.e., the two system monitors. For example, a slippage of the rotational angle position detection device could also be detected.

[0024] According to a particular embodiment, it may be provided that rotational angle positions of the motor rotor detected by the physical rotational angle position detection device and / or rotational angle positions of the motor rotor calculated by the rotational angle position calculation device are continuously stored in a remanent storage device, wherein a recommissioning routine is executed after a power failure to the control or evaluation device and after the power supply to the control or evaluation device has been restored.in which at least one rotational angular position of the motor rotor stored in the remanent storage device prior to the power failure is compared with the rotational angular position of the motor rotor detected by the physical rotational angular position detection device and / or with the rotational angular position of the motor rotor calculated by the rotational angular position calculation device, and wherein, if these rotational angular positions match, the motor can be restarted immediately without recalibration or rereferencing of the motor, in particular of a machine driven by the motor.This is authorized or approved by the control system. This allows for a quick yet safe restart of the motor or the machine it drives, even if the motor position is maintained during a power outage. In particular, this can eliminate the need for time-consuming re-referencing or recalibration of the motor or machine. The power outage to the control or evaluation device can occur suddenly and unexpectedly and / or be caused by a deliberate power interruption.

[0025] Furthermore, it may be provided that the angle-of-rotation position detection device and the angle-of-rotation position calculation device each comprise independent, functionally separate clocking or timing devices, in particular oscillators. This also increases single-fault tolerance, since a single faulty clocking or timing device does not affect both devices for determining the motor or rotor angle of rotation.

[0026] Depending on the specific design, the control or evaluation device may be implemented as an electronic safety controller, include an electronic safety controller, or be connected to an electronic safety controller. This can achieve increased functional availability and / or enhanced evaluation reliability, such as single-fault tolerance. It is advantageous if the safety controller is designed to achieve increased personal safety. Depending on the application, standards such as ISO 10218, ISO 13839, ISO 62061, and ISO 61508 can be considered to implement a safe control or evaluation device or a safe machine. Some of the resulting standards require, for example, that single-fault tolerance be ensured.In particular, the safety control system can minimize the likelihood of an error to such an extent that it cannot occur even over very long periods of time.

[0027] Furthermore, it can be advantageous if, during a test routine, voltage and / or current values ​​are applied to the rotary angle position calculation device that do not correspond to the voltage and / or current values ​​of the motor present at the same time. In the event of an expected discrepancy between the rotary angle position measured by the physical rotary angle position detection device and the rotary angle position calculated by the rotary angle position calculation device, a conclusion can be drawn regarding the functionality of the rotary angle position calculation device, and operation of the control or evaluation device can continue. This allows for a simple verification of the availability and / or correct operation, especially of the rotary angle position calculation device.

[0028] The object of the invention is further solved by a control or evaluation device for controlling an electric motor, wherein this control or evaluation device is configured to implement the method according to the claims.

[0029] Furthermore, the problem of the invention is solved by an at least partially automated controlled machine according to the independent claim to an improved machine.

[0030] This machine comprises at least one electric motor for performing machine movements and a control or evaluation device for operating the electric motor. The control or evaluation device comprises - a physical or sensory angle-of-rotation position detection device, for example an electromechanical encoder, for detecting the angle-of-rotation positions of the motor rotor; - a rotary angle position calculation device for calculating rotary angle positions of the motor rotor, i.e., for sensorless, computational determination of rotary angle positions, which rotary angle position calculation device is designed for this purpose, (i) based on electrical voltages supplied to the motor and / or based on electrical voltages applied to the motor, as well as (ii) to calculate the respective rotational angle positions based on motor currents received by the motor and / or motor currents supplied to the motor, in particular without a physical rotational angle sensor; - wherein the control or evaluation device is configured to compare the rotation angle positions detected by the rotation angle position detection device and the rotation angle positions calculated by the rotation angle position calculation device at the same times, i.e. at temporally corresponding times; - wherein the control or evaluation device is further configured to output or provide at least one control or evaluation signal, which control or evaluation signal includes at least one piece of information regarding equality and / or extent of deviation between detected and calculated rotational angular positions; and - wherein the control or evaluation device is further configured to issue an informative warning message and / or to stop further operation of the motor and / or to establish a safe operating condition for the machine or machine component driven by the motor when a predetermined deviation threshold is reached or exceeded.

[0031] The advantages and technical effects achievable with the machine described above can be found in the preceding and following sections of the description.

[0032] Another advantageous configuration allows for the machine to be a multi-axis machine, such as an industrial robot, with the control or evaluation device configured to control and monitor multiple motors. This makes it possible to upgrade multi-axis machines to a higher safety level at a relatively low cost. Such an upgrade option is particularly beneficial for existing machines, especially multi-axis robots, which, due to their originally installed rotary encoders, offer only limited control-related safety.

[0033] According to an advantageous embodiment, the motor can be designed as a permanent magnet synchronous machine with permanent magnets on its rotor, in particular with permanent magnets attached to the surface of the rotor (PMSM). This rotor design is to be distinguished, for example, from rotor designs with permanent magnets integrated or built into the rotor lamination stack.

[0034] In the claimed motor and rotor design, the motor's characteristics are advantageously linear over a wide operating range. Additionally, the inductances L are d and L q The rotor-fixed coordinates are approximately identical. In contrast, a motor with permanent magnets integrated into the rotor lamination stack exhibits significant non-linear effects, caused by strong saturation and cross-coupling phenomena resulting from the embedded permanent magnets.

[0035] Furthermore, it can be advantageous for the motor to have a distributed stator winding. This contrasts with a design featuring a concentrated winding, i.e., a plurality of concentrated individual coils wound around coil cores. A motor with a distributed stator winding exhibits comparatively significant inductance differences due to its design, making it particularly suitable for sensorless determination of the rotor's angular position.

[0036] To better understand the invention, it is explained in more detail with reference to the following figures.

[0037] They each show, in a highly simplified, schematic representation: Fig. 1 an embodiment of a control system for an exemplary multi-axis industrial robot; Fig. 2 a block diagram of an exemplary embodiment of a control or evaluation device for controlling or regulating an electric motor; Fig. 3 an exemplary characteristic map concerning the course of the d-inductance as a function of the d- and q-current of an electric motor; Fig. 4 an exemplary characteristic map concerning the course of the q-inductance as a function of the d- and q-current of the electric motor according to Fig. 3.; Fig. 5 an exemplary characteristic map concerning the course of the difference between d-inductance and q-inductance as a function of the d- and q-current; Fig. 6 an exemplary test signal of the control or evaluation device and the resulting d and q currents.

[0038] It should be noted at the outset that in the differently described embodiments, identical parts are provided with the same reference numerals or component designations, and the disclosures contained in the entire description can be applied analogously to identical parts with the same reference numerals or component designations. Furthermore, the positional designations chosen in the description, such as top, bottom, side, etc., refer to the figure directly described and illustrated, and these positional designations must be applied analogously to the new position if the position changes.

[0039] In Fig. Figure 1 is a control system, schematically and exemplarily illustrated, which enables the automated execution and / or programming of movements or processes of an industrial robot 2. This industrial robot 2 is representative of any type of machine that can be controlled by a control system.

[0040] Following appropriate programming, the industrial robot 2 or another machine is capable of semi-automatic or fully autonomous execution of movements or processes. The industrial robot 2 can be a multi-axis manipulator unit known from the prior art or another handling unit, with which technical processes, such as welding or painting processes or workpiece handling processes, can be carried out automatically or semi-automatically.

[0041] At least one industrial robot 2 within the control system 1 is assigned at least one integrated and / or external control or evaluation device 3, 3', 3". The control system 1 can be formed by any electrotechnical control or evaluation devices 3, 3', 3" known from the prior art, whereby centralized and / or decentralized control architectures can be used depending on the technological requirements. In particular, a distributed control system 1 can be established by the interaction of several integrated and / or external control or evaluation devices 3, 3', 3" in order to carry out the respective control sequences for a multi-axis industrial robot 2 or for a corresponding automation cell or for another machine.

[0042] According to a suitable embodiment illustrated by way of example, at least one mobile, in particular a portable, control or evaluation device 3' can be implemented or implemented in the control system 1. This mobile or portable control or evaluation device 3' can take over at least some of the control tasks in the control system 1, or the portable control or evaluation device 3' can be integrated into the control system 1 as needed to influence and / or monitor control processes of the industrial robot 2. Such a mobile control or evaluation device 3' is usually arranged in a mobile, in particular portable, handheld terminal 4, as is known from the prior art in numerous embodiments.The control system 1 can therefore optionally include at least one permanently integrated and / or at least one that can be integrated as needed and, if necessary, decoupled from the control system 1, mobile handheld terminal 4.

[0043] This mobile handheld terminal 4 can comprise a plurality of input and output elements to enable the monitoring and / or modification of control processes in the control system 1. These input and output elements are formed in a manner known per se by at least one display 5, preferably in the form of a touchscreen, and by at least one control element 6, 6'. The at least one control element 6, 6' can be a multi-axis control element, in particular a joystick, a jog wheel, and / or conventional switches and pushbuttons, to influence control processes, in particular to modify control parameters.

[0044] At least one control element 6, 6' on the mobile hand terminal 4 can also be provided for software-based, menu-guided interaction with the operator, whereby the mobile hand terminal 4 can function as a human-machine interface (HMI) to the industrial robot 2 or the machine.

[0045] The mobile handheld terminal 4 can, in a manner known per se, include at least one safety switching device 7, which is intended for the operator to influence or control potentially safety-critical movements or processes of the industrial robot 2. Potentially safety-critical movements or processes are understood to be, in particular, traversing movements, changes of state, or process activations that could pose a potential hazard to persons, equipment, or objects. In particular, the safety switching device 7 is intended to minimize the potential hazards with regard to the endangerment of persons and / or property damage, whereby this potential hazard also relates to the industrial robot 2 itself and to surrounding technical equipment as well as to the processes or workpieces being processed.As already explained above, the term industrial robot 2 also includes comparable technical machines or machine systems with a certain automation potential.

[0046] The safety switching device 7 in or on the mobile handheld terminal 4 can comprise at least one enabling switch 8 and, if necessary, an emergency stop switching device, as shown in Fig. Figure 1 is schematically illustrated. The safety technology for the fail-safe and, if possible, reliable evaluation of the corresponding operating states is at least partially implemented in the mobile handheld terminal 4. For this purpose, a fail-safe, in particular multi-circuit, evaluation system is arranged in the handheld terminal 4. Preferably, a safety-tested evaluation software for the safety switching device 7 or for the at least one enabling switch 8 is also implemented in the handheld terminal 4 or in the control system 1.

[0047] The mobile handheld terminal 4 enables comprehensive modification and / or monitoring of operating states or processes of the industrial robot 2. For this purpose, the display 5 and at least one control element 6, 6' of the handheld terminal 4 are used by a suitably authorized operator. The mobile, in particular portable, handheld terminal 4 is expediently held by the operator's hand in such a way that its display 5 or its control elements 6, 6' are visible.

[0048] As is known, the handheld terminal 4 can be functionally integrated into the control system 1 via a cable connection and / or a wireless communication link. For this purpose, it is also possible – as described in Fig. 1 schematically depicted - a separate connection box with a control or evaluation device 3" is provided, which is arranged separately from a primary control or evaluation device 3 of the industrial robot 2 and can represent an optionally connectable, electronic additional module in the control system 1.

[0049] The movements of the industrial robot 2 are implemented, as is known per se, by a plurality of electric motors 9, which are controlled or regulated via the at least one control or evaluation device 3, 3', 3" . For this purpose, the at least one control or evaluation device 3, 3', 3" can comprise at least one drive controller 20, as will be explained below. The motors 9 can be servo motors. According to a preferred embodiment, at least one of the motors 9 of the machine or the industrial robot 2 is designed as a permanent magnet synchronous machine in which the permanent magnets are arranged on the rotor. It is advantageous if the permanent magnets are attached to the surface of the rotor (PMSM). It can also be advantageous if the motor has a distributed stator winding, in particular winding strands running meandering around the outer surface of the stator.

[0050] The various motors 9, in conjunction with the mechanics of the industrial robot 2, form so-called axes of motion 10, which can be defined in particular by rotary and / or linear axes of motion 10.

[0051] By incorporating sensors or encoders, controlled motion sequences of the industrial robot 2 can be achieved. Typically, an industrial robot 2 includes physical rotary angle position sensing devices 11 assigned to the respective motors 9 or motion axes 10. These rotary angle position sensing devices 11 can be incremental position encoders and / or absolute position encoders 12. It can be advantageous if the absolute position encoders 12 are designed as so-called absolute multiturn encoders. It can also be advantageous if at least some of the motors 9 of the industrial robot 2 are assigned both incremental position encoders and absolute position encoders 12. This ensures comprehensive control of the motion sequences of the industrial robot 2.

[0052] According to one possible embodiment of the industrial robot 2, at least individual rotary angle position detection devices 11 can be implemented using safe technology. Components or position encoders implemented using safe technology can be defined by two- or multi-channel signal acquisition and / or signal evaluation and / or be characterized by technically diverse designs. In contrast, rotary angle position detection devices 11 that are implemented using standard technology or quasi-“non-safe technology” are, for example, implemented with only one channel. In particular, the rotary angle position detection devices 11 implemented using standard or “non-safe technology” are not able to meet or achieve the increased reliability or safety standards of an encoder or sensor implemented using safe technology. One advantage of such devices implemented using standard or non-safe technology is that they are not designed with a single channel.The advantage of rotary angle position sensing devices 11, which are implemented using "less reliable" technology, lies in the fact that they are comparatively inexpensive and relatively easy to implement. Therefore, machines or industrial robots 2 with standard or single-channel rotary angle position sensing devices 11 for the motors 9 are widely used.

[0053] According to an optional embodiment, at least one braking device 13 can also be assigned to those motion axes 10 or motors 9 that are to be protected against automatic adjustment or against unwanted, load-induced movement. Typically, such a braking device 13 is assigned to all motors 9 or motion axes 10 that can be activated and deactivated or controlled by the control system. Alternatively or in combination, active standstill control for the motors 9 can also be implemented. Such active standstill control can, for example, be implemented by drive controllers 20 for the motors 9, as described below.

[0054] By controlling the motors 9 in a manner known per se and taking into account the data or sensor signals received from the rotary angle position detection devices 11, a coordinated movement of the machine, for example of the so-called tool center TCP or the end effector 14 of the industrial robot 2, can then be achieved.

[0055] The energy required for the movements of the machine or industrial robot 2 is supplied by at least one electrical power supply network 15. This power supply network 15 enables the operation of at least the motors 9 and the at least one control or evaluation device 3, 3" of the industrial robot 2. Naturally, various energy conversions based on the electrical energy supplied by the electrical power supply network 15 can also take place. For example, pneumatic or hydraulic power supply systems can also be provided for the planned operation of the industrial robot 2.

[0056] At least one of the control devices 3, 3', 3" can include a remanent storage device 16 in which the rotation angle position data of the motors 9 or motion axes 10 and / or the tool center point TCP are stored at least temporarily, in particular at least during the control processing or path calculations, and / or permanently. This storage device 16 can therefore include temporarily storing and / or permanently storing memory modules, such as flash memory and / or RAM memory and / or magnetic storage devices.

[0057] In Fig. Figure 2 shows an advantageous control or evaluation device 3, 3', 3" for controlling or operating an electric motor 9, wherein this motor 9 is located in a machine or in the industrial robot 2 according to Fig. 1 can be used.

[0058] The control or evaluation device 3, 3', 3" comprises a physical rotation angle position detection device 11 on or for the motor 9, for example an absolute value position encoder 12. The physical rotation angle position detection device 11 is provided for detecting the respective rotation angle positions of the rotor of the motor 9.

[0059] The control or evaluation device 3, 3', 3" further comprises a rotation angle position calculation device 17 for calculating the rotation angle positions of the motor rotor. The rotation angle position calculation device 17 is configured to calculate the respective rotation angle positions of the rotor based on the electrical voltages 18 supplied to the motor 9 or their values, and / or based on the electrical voltages 18 applied to the motor 9 or their values, as well as based on the motor currents 19 drawn by the motor 9 or their values, and / or based on the motor currents 19 supplied to the motor 9 or their values. The electrical voltages 18 and the motor currents 19 for operating or controlling the motor 9 are provided by a power electronic drive controller 20.

[0060] The control or evaluation device 3, 3', 3" is configured to compare the rotational angular positions of the rotor physically detected by the rotational angle position detection device 11 with the rotational angle position calculated or estimated to a certain extent by the rotational angle position calculation device 17 at the same time. The control or evaluation device 3, 3', 3" is further configured to output or provide at least one control or evaluation signal 21, which includes at least information regarding the equality and / or extent of deviation between detected and calculated rotational angle positions. The control or evaluation signal 21 can, for example, be supplied to the drive controller 20 for further processing or corresponding conversion, or supplied to a peripheral control device.

[0061] The control or evaluation device 3, 3', 3" can be designed as an electronic safety controller 22, comprise an electronic safety controller 22, or be connected to an electronic safety controller 22. For example, the safety controller 22 performs a value-based comparison between the rotational angle positions of the rotor detected by the rotational angle position detection device 11 and the rotational angle positions of the rotor calculated by the rotational angle position calculation device 17.

[0062] Furthermore, the control or evaluation device 3, 3', 3" is configured to issue an informative warning message and / or to stop the operation of the motor 9 and / or to establish a safe operating state for the machine or machine component driven by the motor 9 when a predetermined deviation threshold is reached or exceeded. This can be achieved by means of the control or evaluation signal 21. This increases the safety of the controlled machine or industrial robot 2.

[0063] The control or evaluation device 3, 3', 3" can also be configured to control several motors 9 of a machine, for example from the one in Fig. 1 illustrated industrial robot 2, to control and monitor.

[0064] For example, the physical or electromechanical rotary angle position detection device 11 can be queried via a sensor interface 23. The sensor interface 23 is connected to the drive controller 20 and the safety controller 22 via signals or data. This sensor interface 23 is configured to provide the rotary angle positions of the motor 9's rotor as detected by the rotary angle position detection device 11. The physical detection principle used by the rotary angle position detection device 11 is not of particular importance.

[0065] As is known per se, the power electronic drive controller 20 for operating the electric motor 9 includes an internal current, speed, and / or position control 24. This current, speed, and / or position control 24 provides the respective voltages 18 and motor currents 19 for operating the motor 9. A first input variable for the drive controller 20 is the rotational angular position of the rotor of the motor 9 detected by the angle-of-rotation position sensing device 11. A further input variable can be defined by a target position 25, which can originate from an external request or be specified by the control or evaluation device 3, 3', 3". Based on such a target position 25, the drive controller 20 attempts to achieve the corresponding target position of the motor 9 or the axis of motion 10 by controlling or regulating the motor 9. Fig. 1 - to reach.

[0066] The drive controller 20 further includes a current measuring unit 26 which is configured to determine the currents drawn by the motor 9, i.e., the values ​​of the motor currents 19. The determined motor currents 19 are provided or transmitted to the current, speed, and / or position control unit 24 and to the angle-position calculation device 17. In the current, speed, and / or position control unit 24, the values ​​of the motor currents 19 are processed electronically for control purposes of the motor 9. In the angle-position calculation device 17, the values ​​of the motor currents 19 are processed electronically for the calculation of the angle positions of the rotor of the motor 9.

[0067] The rotation angle position calculation device 17 can include a Kalman filter 27 (KMF), in particular an extended Kalman filter (EKMF). This Kalman filter 27 includes a mathematical description of the motor 9, which mathematical description was created in a previous step. Based on the values ​​of the voltages 18 and motor currents 19 supplied to the motor 9, the respective rotation angle positions of the rotor relative to the stator of the motor 9 can be calculated using the mathematical description of the motor 9.

[0068] In particular, the rotation angle-position calculation device 17, preferably a Kalman filter 27 or an extended Kalman filter 27, models the motor 9 based on a plurality of previously determined operating-point-dependent inductance values ​​L, especially also based on differential inductances. This is done in particular by describing the operating points as a function of currents and / or positions and / or torque and / or voltages and based on inductance characteristic maps L. d , L q , L Diff , as can be seen with reference numbers 28, 29, 30 in the Fig. 3, Fig. 4, Fig. 5 is shown as an example. Based on the respective voltages 18 and motor currents 19 and the previously determined model, which may include in particular the inductance values ​​L, the motor characteristic curves and other parameters, the respective rotational angular positions of the rotor are derived computationally.

[0069] For the metrological determination of the inductances L of the motor 9 or for recording the inductance characteristic curves L d , L q , L Diff For the motor 9, it can be advantageous if a test signal 31 is applied to the motor 9 by the rotation angle position calculation device 17, in particular by the drive controller 20. The inductance differences L of the motor 9, typically caused by iron saturation effects, are determined via this test signal 31. Based on asymmetries in the inductances L of the motor 9, the rotation angle position of the rotor can then be calculated or estimated by the rotation angle position calculation device 17 using an algorithm. In the lower section of Fig. Figure 6 illustrates an example test signal 31. This test signal 31 is superimposed on the voltages 18 of the drive controller 20 and generates pseudo-random noise in the motor currents 19 ( Fig. 6 (top and middle). The corresponding voltage and current waveforms at the respective operating points of the motor 9 can be recorded by the drive controller 20. In Fig. Figure 6 above shows a curve of the motor current i d - 32 - and in Fig. 6 Middle is a curve of the motor current i q - 33 - illustrated by example.

[0070] By including inductance values ​​L or inductance characteristic maps L d , L q , L Diff of engine 9 ( Fig. 3, Fig. 4, Fig. 5) It is also possible for the calculation of rotational angle positions using the rotational angle position calculation device 17 to take place at times when the motor 9 is not moving, in particular when the motor 9 is in a standstill controlled by a drive controller 20 of the motor 9 or in a braked standstill. By comparing the determined rotational angle positions from the physical rotational angle position detection device 11 and the calculated rotational angle positions from the rotational angle position calculation device 17, the detection information can be checked for plausibility, and the basic reliability of the control or evaluation device 3, 3', 3" can thus be increased.

[0071] In Fig. 6, in particular based on the lower diagram comprising the test signal 31, it can be seen by way of example that in order to determine the inductance values ​​L of the motor 9, this motor 9 - preferably while at standstill or at low speeds - is subjected to a time-varying voltage signal u q (q-voltage 34) and with a time-varying voltage signal u d (d-voltage 35) is applied. Using this q-voltage 34 and d-voltage 35, the L d -Inductance characteristics ( Fig. 3) and L q -Inductance characteristics ( Fig. 4) be improved or recorded more extensively.

[0072] Based on the time-varying voltage signal u q (q-voltage 34) and the time-varying voltage signal u d (d-voltage 35) the respective waveforms of the motor currents i q (q-current 33) and i d(d-current 32) measured. Based on this, the inductance values ​​L can be determined. q (q-inductance) - Fig. 4 - and L d (d-inductance) - Fig. 3 - can be calculated and, for example, the inductance values ​​L q (q-inductance) and L d (d-inductance) for the mathematical description of motor 9 in a data-technical model; if necessary, this also applies to the inductance characteristic L. Diff ( Fig. 5, reference number 30). The mathematical description or the corresponding data-technical model can then be applied to the rotation angle position calculation device 17, in particular the Kalman filter 27 ( Fig. 2) for subsequent calculations of rotation angle positions of the rotor of motor 9.

[0073] Furthermore, it may be provided that, after a calculation has been made to determine that the calculated inductance values ​​L q (q-inductance 29) and Ld (d-inductance 28) have not reached a predetermined minimum difference at individual rotor positions, the voltage signal u q (q-voltage 34) and / or the voltage signal u d (d-voltage 35), for example by injecting an additive displacement signal 36 ( Fig. 2) is modified in such a way that a predetermined minimum difference between the inductance values ​​L q (q-inductance 29) and L d (d-inductance 28), which predetermined minimum difference enables a reliable calculation of the rotational angle positions of the rotor, is achieved.

[0074] It can also be provided that, in a standstill state of the motor 9, a time-varying test signal 37, in particular a noise signal, a high-frequency sine signal or another signal form, is supplied to the motor 9 without noticeably setting the motor 9 in motion. Based on the resulting test currents and the supplied test signal 37, the rotation angle position calculation device 17, in particular using a Kalman filter 27, can be used to determine ( Fig. 2) the current standstill position of the rotor is calculated.

[0075] It can also be provided that a time-varying test signal 37, in particular a noise signal, a high-frequency sine wave, or another signal form, is supplied. This time-varying test signal 37, in particular a noise signal, a high-frequency sine wave, or another signal form, can be variable depending on the motor's speed. It is particularly advantageous here to apply the time-varying test signal to the motor 9 in the lower speed range, e.g., in the range from 0 to an application-specific maximum speed, which is in any case below the rated speed. Furthermore, it can be advantageous if the magnitude of the test signal changes with the motor's speed and, in particular, decreases with increasing speed. This applies especially to low speeds or in ranges where the motor 9 moves only imperceptibly.An unwanted, additional torque in the motor 9 can also be kept small (e.g., by supplying d-current or d-voltage). Based on the resulting test currents and the supplied test signal 37, the rotation angle position calculation device 17, in particular using a Kalman filter 27, is used. Fig. 2) calculated the respective rotation angle positions of the rotor.

[0076] Initiated by the control or evaluation device 3, 3', 3" it can also be provided that in a first step a rotor rotation of at least 360° is carried out and the determined rotation angle positions are stored in a memory 38, and wherein in a second step a coincidence check is carried out in which the currently determined rotation angle positions are checked for coincidence with the rotation angle positions stored in the memory 38.

[0077] It can also be provided that rotational angle positions of the rotor of the motor 9 detected by the physical rotational angle position detection device 11 and / or rotational angle positions of the rotor of the motor 9 calculated by the rotational angle position calculation device 17 are continuously stored in a remanent storage device 16 ( Fig. 1, Fig. 2) are stored, wherein, after the occurrence of a power failure with respect to the control or evaluation device 3, 3', 3" and after the restoration of the power supply with respect to the control or evaluation device 3, 3', 3" a restart routine is executed, in which at least one rotational angular position of the rotor of the motor 9 stored in the remanent storage device 16 before the power failure is compared with the rotational angular position of the rotor of the motor 9 detected by the physical rotational angular position detection device 11 and / or with the rotational angular position of the rotor of the motor 9 calculated by the rotational angular position calculation device 17, and wherein, if these rotational angular positions match, an immediate restart of the motor 9 without recalibration or referencing of the motor 9, in particular of a machine driven by the motor 9, is authorized.

[0078] According to one embodiment, it can also be provided that the rotary angle position detection device 11 and the rotary angle position calculation device 17 each comprise independent, functionally separate clocking or timing devices 39, 40, as shown in Fig. 2 is illustrated schematically.

[0079] According to a further development, it can be provided that voltage values ​​and / or current values ​​are supplied to the rotary angle position calculation device 17 during a test routine 41, which do not correspond to the voltage values ​​18 and / or current values ​​19 of the motor 9 present at the same time, and in the course of an expected discrepancy between the rotary angle position measured by the physical rotary angle position detection device 11 and the rotary angle position calculated by the rotary angle position calculation device 17, a conclusion is drawn about the functionality of the rotary angle position calculation device 17 and the operation of the control or evaluation device 3, 3', 3" is continued.

[0080] The exemplary embodiments show possible embodiment variants, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiment variants, but rather various combinations of the individual embodiment variants are also possible and this possibility of variation lies within the skill of the person skilled in this technical field due to the teaching on technical action by the present invention.

[0081] The scope of protection is defined by the claims. However, the description and drawings must be consulted for the interpretation of the claims. Individual features or combinations of features from the different embodiments shown and described can, in themselves, represent independent inventive solutions. The problem underlying these independent inventive solutions can be found in the description.

[0082] Finally, for the sake of clarity, it should be noted that, for a better understanding of the structure, some elements have been shown not to scale and / or enlarged and / or reduced in size. Reference numeral list 1 Control system 2 industrial robots 3, 3', 3" control or evaluation device 4 handheld terminals 5 Display 6, 6' Control element 7 Safety switching device 8 Enabling switches 9 engine 10 axis of movement 11 Rotation angle position detection device 12 Absolute value position transmitters 13 Brake device 14 End effector 15 Energy supply network 16 Retentive storage device 17 Rotation angle position calculation device 18 tensions 19 motor currents 20 drive controllers 21 Control or evaluation signal 22 Safety control 23 Transmitter interface 24 Current, speed and / or position control 25 Target position 26 Current measuring unit 27 Kalman filters 28 Inductance characteristic L d 29 Inductance characteristic L q 30 Inductance characteristic L Diff 31 Test signal 32 Motor current i d 33 Motor current i q 34 q-voltage 35 d voltage 36 Displacement signal 37 Test signal 38 memory 39 Clocking or timing device 40 Clocking or timing device 41 Test routine QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2020 / 087099A1

[0002] Cited non-patent literature

[0000] ISO 10218

[0026] ISO 13839

[0026] ISO 62061

[0026] ISO 61508

[0026]

Claims

[1] Method for operating an electric motor (9) comprising the steps - Detection of rotational angle positions of the rotor of the motor (9) by means of a physical rotational angle position detection device (11); - Calculating rotation angle positions of the motor rotor (9) using a rotation angle position calculation device (17), which rotation angle position calculation device (17) is set up for this purpose, (i) based on electrical voltages (18) supplied to the motor (9) and / or based on electrical voltages (18) applied to the motor (9), as well as (ii) to calculate the respective rotational angle positions based on motor currents (19) received by the motor (9) and / or motor currents (19) supplied to the motor (9); - Comparing the rotation angle positions detected by the rotation angle position detection device (11) and the rotation angle positions calculated by the rotation angle position calculation device (17) at the same times by means of a control or evaluation device (3, 3', 3"); - Output or provision of at least one control or evaluation signal (21) by means of the control or evaluation device (3, 3', 3"), which control or evaluation signal (21) includes at least one piece of information regarding equality and / or extent of deviation between detected and calculated rotation angle positions; - Issuing an informative warning message and / or stopping further operation of the motor (9) and / or establishing a safe operating condition for a machine or machine component driven by the motor (9) when a predetermined deviation level is reached or exceeded. [2] Method according to claim 1, wherein the rotational angular positions of the rotor are calculated based on the motor voltages (18) and motor currents (19) by feeding the motor voltages (18) and motor currents (19) to a Kalman filter (27), in particular an extended Kalman filter (EKMF), wherein the Kalman filter (27) comprises a mathematical description of the motor (9). [3] Method according to claim 1 or 2, wherein the rotation angle position calculation device (17), in particular a Kalman filter (27), maps the motor (9) on the basis of a plurality of inductance values ​​(L) at different voltage operating points and / or current operating points and the respective rotation angle positions of the rotor are derived therefrom. [4] Method according to one of the preceding claims, wherein a test signal (31) is impressed on the motor (9), via which test signal (31) the inductances (L) of the motor (9) are determined, preferably taking into account iron saturation effects, and wherein the rotation angle position calculation device (17) determines the respective rotation angle positions of the rotor based on asymmetries of the inductances (L) of the motor (9). [5] Method according to one of the preceding claims, wherein the comparison of the determined rotation angle positions from the physical rotation angle position detection device (11) and the calculated rotation angle positions from the rotation angle position calculation device (17) is carried out at a time when the motor (9) is not moving, in particular when the motor (9) is in a standstill controlled by a drive controller (20) of the motor (9) or is in a braked standstill. [6] Method according to one of the preceding claims, wherein, to determine the inductance values ​​(L) of the motor (9), this motor (9) is preferably supplied with a time-varying voltage signal u while it is at rest. q (q-voltage 34) and with a time-varying voltage signal u d (d-voltage 35) is applied, based on this (i) the respective waveforms of the motor currents i q (q-current 33) and i d (d-current 32) are measured, based on this (ii) the inductance values ​​L q (q-inductance) and L d (d-inductance) can be calculated, (iii) the inductance values ​​L q (q-inductance) and L d(d-inductance) for the mathematical description of the motor (9) in a data-technical model, and (iv) the rotation angle position calculation device (17) for subsequent calculations of rotation angle positions of the rotor of the motor (9) are provided. [7] Method according to any one of the preceding claims, wherein as a result of a finding that determined inductance values ​​L q (q-inductance) and L d (d-inductance) of the motor (9) have not reached a predetermined minimum difference at individual rotor positions, by imprinting an additive displacement signal (36) which changes the magnetic operating point, for example by imprinting an additional current, in particular d-current, such that a predetermined minimum difference between the inductance values ​​L q (q-inductance) and L d(d-inductance), which predetermined minimum difference enables a reliable calculation of the rotational angle positions of the rotor. [8] Method according to one of the preceding claims, wherein a time-varying test signal (37), in particular a noise signal, a high-frequency sine signal or another signal shape, is supplied to the motor (9) and wherein the current position of the rotor is calculated by means of the resulting test currents and on the basis of the supplied test signal by means of the rotation angle position calculation device (17), in particular using a Kalman filter (27). [9] Method according to one of the preceding claims, wherein, depending on the rotational speed of the motor (9), a time-varying test signal (37), in particular a noise signal, a high-frequency sine signal or another signal form, is supplied to the motor (9), wherein the time-varying test signal (37) is given in particular in the lower speed range and / or is designed to be variable in speed, and wherein the respective rotational angle positions of the rotor are calculated by means of the resulting test currents and on the basis of the supplied test signal (37) using the rotation angle position calculation device (17), in particular using a Kalman filter (27). [10] Method according to one of the preceding claims, wherein in a first step a rotor rotation of at least 360° is performed and the determined rotation angle positions are stored in a memory (38), and wherein in a second step a coincidence check is performed in which the currently determined rotation angle positions are checked for coincidence with the rotation angle positions stored in the memory (38). [11] Method according to one of the preceding claims, wherein rotational angle positions of the rotor of the motor (9) detected by the physical rotational angle position detection device (11) and / or rotational angle positions of the rotor of the motor (9) calculated by the rotational angle position calculation device (17) are continuously stored in a remanent storage device (16), wherein a restart routine is executed after the occurrence of a power failure to the control or evaluation device (3, 3', 3") and after the power supply to the control or evaluation device (3, 3', 3") has been restored,in which at least one rotational angular position of the rotor of the motor (9) stored in the remanent storage device (16) before the power failure is compared with the rotational angular position of the rotor of the motor (9) detected by the physical rotational angular position detection device (11) and / or with the rotational angular position of the rotor of the motor (9) calculated by the rotational angular position calculation device (17), and wherein, if these rotational angular positions match, an immediate restart of the motor (9) without recalibration or rereferencing of the motor (9), in particular of a machine driven by the motor (9), is authorized. [12] Method according to one of the preceding claims, wherein the angle-of-rotation position detection device (11) and the angle-of-rotation position calculation device (17) each comprise independent, functionally independent timing or timer devices (39, 40). [13] Method according to any of the preceding claims, wherein the control or evaluation device (3, 3', 3") is designed as an electronic safety controller (22), comprises an electronic safety controller (22), or is connected to an electronic safety controller (22). [14] Method according to one of the preceding claims, wherein voltage values ​​and / or current values ​​are supplied to the rotary angle position calculation device (17) during a test routine (41) which do not correspond to the voltage values ​​(18) and / or current values ​​(19) of the motor (9) present at the same time, and wherein, in the event of an expected discrepancy between the rotary angle position measured by the physical rotary angle position detection device (11) and the rotary angle position calculated by the rotary angle position calculation device (17), a conclusion is drawn regarding the functionality of the rotary angle position calculation device (17) and the operation of the control or evaluation device (3, 3', 3") is continued. [15] Control or evaluation device (3, 3', 3") for controlling an electric motor (9), characterized by, that the control or evaluation device (3, 3', 3") is configured to implement the method according to one of the preceding claims. [16] machine comprising - at least one electric motor (9) for performing machine movements, and - a control or evaluation device (3, 3', 3") for operating the electric motor (9), comprising the control or evaluation device (3, 3', 3") -- a physical rotation angle position detection device (11) for detecting rotation angle positions of the rotor of the motor (9); -- a rotation angle position calculation device (17) for calculating rotation angle positions of the rotor of the motor (9), which rotation angle position calculation device (17) is set up for this purpose, (i) based on electrical voltages (18) supplied to the motor (9) and / or based on electrical voltages (18) applied to the motor (9), as well as (ii) to calculate the respective rotational angle positions based on motor currents (19) received by the motor (9) and / or motor currents (19) supplied to the motor (9); - wherein the control or evaluation device (3, 3', 3'') is configured to compare the rotation angle positions detected by the rotation angle position detection device (11) and the rotation angle positions calculated by the rotation angle position calculation device (17) at the same times; - wherein the control or evaluation device (3, 3', 3'') is further configured to output or provide at least one control or evaluation signal (21) which control or evaluation signal (21) includes at least one piece of information regarding equality and / or extent of deviation between detected and calculated rotational angular positions; and - wherein the control or evaluation device (3, 3', 3'') is further configured to issue an informative warning message and / or to stop further operation of the motor (9) and / or to establish a safe operating condition for the machine or machine component driven by the motor (9) when a predetermined deviation threshold is reached or exceeded. [17] Machine according to claim 16, wherein the machine is a multi-axis machine, for example an industrial robot (2), and wherein the control or evaluation device (3, 3', 3'') is configured to control and monitor several motors (9) of the machine. [18] Machine according to claim 16 or 17, wherein the motor (9) is designed as a permanent magnet excited synchronous machine with permanent magnets on its rotor, in particular with permanent magnets attached to the surface of the rotor (PMSM). [19] Machine according to any one of claims 16 to 18, wherein the motor (9) has a distributed stator winding.

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