Control system for motor of roof assembly and method thereof

Abstract

A control system for operating a motor of a roof assembly includes a speed controller, a current controller, a motor, and a performance feed-forward module. The control system is configured to receive a speed setpoint as an input, feed back a speed signal, and determine a speed error. A current setpoint is provided and a current output is fed back to the current setpoint, and a current error signal is provided to the current controller. The relative position signal is fed back, and a current feed-forward signal is fed forward to the current setpoint based on at least one performance profile determined from the absolute position signal. And generating a driving signal for driving a motor based on the current error signal and the relative position signal. The current error signal is based on the current setpoint, the current feedback, and the current feedforward.

Description

Technical Field

[0001] This invention relates to a control system for a motor in a vehicle roof assembly, and to a method for controlling the operation of the motor in such a roof assembly. More specifically, this invention relates to field-oriented control (FOC) for a motor in a roof assembly. The roof assembly can be an open roof assembly with a movable panel or a roof assembly with a movable sun visor. Background Technology

[0002] By operating a motor, the movable panel of the open roof assembly can move between an open and closed position. Similarly, by operating a motor, the sun visor of the roof assembly can move between an open and closed position. The speed of the motor determines the speed at which the movable components (i.e., the roof panel or sun visor) move. To ensure smooth operation of the movable panel, the speed is preferably controlled in a predetermined manner. Furthermore, the drive unit typically includes a speed controller that receives a setpoint as input for controlling the motor speed. To adjust the input and consequently the motor speed, the actual speed of the motor is fed back to the speed controller and compared with the setpoint. The actual speed can be obtained from a direct measurement of the speed or indirectly from motor variables indicating performance, such as current or voltage. Depending on the type of motor, indirect measurements may include other variables and / or parameters, such as (angular) position estimates. In the case of indirect measurements, sensorless motor control can be provided, often referred to as sensorless control.

[0003] However, the smooth, predetermined movement of the movable panel can be hindered by factors such as temperature, humidity, and other environmental factors that determine the viscosity of the materials. Furthermore, aging of the roof assembly can further degrade the operation of the movable panel over time.

[0004] Therefore, an improved motor control method is needed. Summary of the Invention

[0005] The purpose of this invention is to provide a control system that alleviates the above-mentioned problems.

[0006] In one aspect, the present invention relates to a control system for operating a motor of a roof assembly, the control system comprising a speed controller, a current controller, a motor, and a performance feedforward module. The control system is configured to receive a speed setpoint as input, feed a speed signal from the motor back to the input, and determine a speed error; the speed controller provides a current setpoint based on the speed error. It is also configured to feed a current output from the motor back to the current setpoint, determine a current error signal, and provide the current error signal to the current controller. A relative position signal is fed back to the current controller; the performance feedforward module feeds a current feedforward signal to the current setpoint based on an absolute position signal. The current controller generates a drive signal for driving the motor based on the current error signal and the relative position signal. The determination of the current error signal is based on the current setpoint, the current feedback, and the current feedforward.

[0007] The relative position signal indicates the relative position of the rotor relative to the stator. The absolute position signal indicates the absolute position of the motor and / or a movable component on a track driven by the motor. The performance feedforward module may include at least one performance profile of a corresponding set of operating conditions. The performance feedforward module may be configured to store and / or update the at least one performance profile in response to receiving position-related performance feedback of the corresponding set of operating conditions. The performance feedforward module may also be configured to store another performance profile in response to detecting or receiving another set of operating conditions. Furthermore, the performance feedforward module may store torque and / or current as a function of absolute position.

[0008] In another aspect, the present invention relates to a method for controlling a motor of a roof assembly of an operating vehicle, the roof assembly including a roof panel movable between a closed position and an open position via the motor, the method comprising: receiving a speed setpoint as input, feeding back a speed feedback signal from the motor to the input, and determining a speed error. The method further comprises: providing a current setpoint based on the speed error; feeding back a current output from the motor to the current setpoint, and determining a current error signal; feeding back a relative position signal; feeding forward a current feedforward signal to the current setpoint based on a performance curve determined from an absolute position signal; and generating a drive signal for driving the motor based on the current error signal and the relative position signal. The current error signal is determined based on the current setpoint, the current feedback, and the current feedforward.

[0009] The relative position signal can indicate the relative position of the rotor and stator. The absolute position signal can indicate the absolute position of the motor and / or a movable component on a track driven by the motor. The at least one performance curve can correspond to at least one corresponding set of operating conditions. The at least one performance curve can store torque and / or current as a function of absolute position.

[0010] The method may further include updating the at least one performance curve in response to receiving location-related performance feedback of a corresponding set of operating conditions. The method may also include storing another performance curve in response to detecting or receiving another set of operating conditions.

[0011] In another aspect, the present invention relates to a roof assembly for a vehicle, comprising a roof panel and / or sun visor movable between a closed position and an open position. A control system is also included, configured to operate the roof panel and / or sun visor to move between the closed and open positions. Furthermore, the system is configured to perform the disclosed method.

[0012] Specific embodiments of the invention are set forth in the dependent claims.

[0013] Other objects, aspects, effects, and details of specific embodiments of the invention are described in the following detailed description of several exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0014] By way of example only, embodiments of this disclosure will be described with reference to the accompanying drawings, in which:

[0015] Figure 1A A perspective view of an example of a roof with an open roof assembly is shown;

[0016] Figure 1B It shows Figure 1A Exploded view of the open roof assembly;

[0017] Figure 2 The stator-rotor configuration of a brushless motor is schematically shown;

[0018] Figure 3 An example of a control system for a brushless motor according to the present invention is shown schematically;

[0019] Figure 4 Another example of a control system for a brushless motor according to the present invention is illustrated schematically;

[0020] Figure 5 Showing more details Figure 4 Examples of control systems; and

[0021] Figure 6A method for controlling a brushless motor according to the present invention is shown. Detailed Implementation

[0022] In the following description, spatial references to directions such as front, side and rear, or below, under and above, or forward and backward, as well as driving movement, are made relative to the overall orientation of the vehicle (such as a passenger car), and particularly relative to the driver, such as behind the steering wheel. In the accompanying drawings, forward driving movement of the vehicle may be indicated, for example, by an arrow D pointing in the direction toward the front of the vehicle.

[0023] Figure 1A and 1B A vehicle roof with an open roof assembly 1 disposed therein is shown. The open roof assembly 1 includes a movable panel 2a and a fixed panel 2b. The movable panel 2a is also referred to as a closing member because it is movable above a first roof opening 3a to enable opening and closing of the first roof opening 3a. A wind deflector 4 is disposed on the front side of the first roof opening 3a.

[0024] In the illustrated embodiment, the movable panel 2a can be in a closed position, where it is positioned above and closes the first roof opening 3a, and is therefore typically positioned within the plane of the roof 1. Furthermore, the movable panel 2a can be in an inclined position, where its rear end RE is raised compared to the closed position, while its front end FE remains closed. Additionally, the panel 2a can be in an open position, where it slides open and the first roof opening 3a is partially or completely exposed. In the open position, for example, both the rear end RE and the front end FE can be raised compared to the closed position.

[0025] It should be noted that the roof 1 shown corresponds to a passenger vehicle. However, the invention is not limited to passenger vehicles. It is also conceivable that any other type of vehicle may be equipped with a movable panel.

[0026] Figure 1B It shows the relationship with Figure 1A The same roof shown has panels 2a and 2b. Specifically, although... Figure 1A The open roof assembly 1 is shown in the open position, but... Figure 1B This is an exploded view of the open roof assembly 1 in the closed position. Furthermore, in Figure 1B The exploded view shows the presence of a second roof opening 3b. The first and second roof openings 3a and 3b are disposed within the frame 5 of the open roof assembly 1. The edge 5a of the frame 5 defines the first roof opening 3a.

[0027] The second roof opening 3b is arranged below the fixed panel 2b, allowing light to enter the vehicle interior space through the fixed panel 2b, assuming the fixed panel 2b is a glass panel or a similar transparent panel, for example, made of plastic or any other suitable material. The second roof opening 3b with a transparent or translucent fixed panel 2b is optional and may be omitted in another embodiment of the open roof assembly 1.

[0028] The wind deflector 4 is typically made of a flexible material, such as a woven or nonwoven fabric or mesh with through-holes arranged therein. The flexible material is supported by a support structure 4a (e.g., a strip or tubular structure), which is hinged directly or indirectly to the frame 5 at a hinge 4b.

[0029] The wind deflector 4 is positioned in front of the first roof opening 3a and adjusts airflow when the movable panel 2a is in the open position. In its raised position, the wind deflector 4 reduces annoying noise caused by airflow during driving. When the movable panel 2a is in the closed or tilted position, the wind deflector 4 is held below the front end FE of the movable panel 2a.

[0030] Normally, when the movable panel 2a slides to the open position, the wind deflector 4 is raised by spring force, and when the movable panel 2a slides back to its closed position, the wind deflector 4 is pushed downwards by the movable panel 2a. Figure 1A In the image, the movable panel 2a is shown in the open position, and the wind deflector 4 is shown in the raised position. Figure 1B In the image, the movable panel 2a is shown in the closed position, and the wind deflector 4 is correspondingly shown in the position where it is held below.

[0031] Figure 1B A drive assembly having a first guide component 6a, a second guide component 6b, a first drive cable 7 and a second drive cable 8, and a drive motor 9 is also shown. The first and second guide components 6a and 6b are arranged on corresponding side ends SE of the movable panel 2a and may each include a guide and a mechanism. The guide is coupled to the frame 5, while the mechanism includes movable parts and is slidably movable within the guide. The first and second drive cables 7 and 8 are disposed between the mechanism of the respective guide components 6a and 6b and the drive motor 9.

[0032] Drive cables 7 and 8 connect drive motor 9 to the mechanisms of the corresponding guide components 6a and 6b, such that the mechanisms begin to move when drive motor 9 is operated. Specifically, the cores of drive cables 7 and 8 are moved by drive motor 9 to push or pull the mechanisms of the corresponding guide components 6a and 6b. Such drive components are well known in the art and will not be described further herein. Moreover, any other suitable drive components may be used without departing from the scope of the invention.

[0033] In the illustrated embodiment, guide components 6a, 6b can initiate movement by raising the rear end RE of the movable panel 2a, thereby placing the movable panel 2a in an inclined position. Then, guide components 6a, 6b can slide from the inclined position to place the movable panel 2a in an open position. However, the invention is not limited to such embodiments. For example, in another embodiment, the movable panel 2a can be moved to the inclined position by raising the rear end RE, while simultaneously reaching the open position by first lowering the rear end RE and then sliding the movable panel 2a under the fixed panel 2b or any other structure or element disposed behind the rear end RE of the movable panel 2a. In another exemplary embodiment, the movable panel 2a may move only between a closed position and an inclined position, or between a closed position and an open position.

[0034] In the illustrated embodiment, the drive motor 9 is mounted in a recess 10 near or below the front end FE of the movable panel 2a in the closed position. In another embodiment, the drive motor 9 can be positioned at any other suitable location. For example, the drive motor 9 can be arranged near or below the rear end RE of the movable panel 2a in the closed position, or below the fixed panel 2b.

[0035] Control unit 11 is schematically shown and operatively coupled to drive motor 9. Control unit 11 can be any type of processing unit known to those skilled in the art, either a software-controlled processing unit or a dedicated processing unit such as an ASIC. Control unit 11 can be a standalone control unit, or it can be operatively connected to another control unit, such as a multi-purpose vehicle control unit. In another embodiment, control unit 11 can be embedded in or part of such a multi-purpose vehicle control unit. Essentially, control unit 11 can be implemented by any control unit suitable for, capable of, and configured to perform operations on drive motor 9 and thus on the movable roof assembly 1.

[0036] An electric motor is used to operate the movable panels of the roof assembly. Brushless electric motors have been developed to avoid the brushes required in conventional brushed electric motors. Various types of brushless motors exist, differing in how the windings are applied, which in turn determines the required drive signal: trapezoidal DC for brushless DC (BLDC) or sinusoidal AC for permanent magnet synchronous motors. The advantage of either of these brushless motors is the absence of wear due to contact between the brushes and the commutator located on the rotor axis. They also operate more quietly and generate less heat. Therefore, from the perspective of noise, vibration, and roughness, these brushless electric motors are more desirable for operating the roof assembly. However, controlling such a motor requires additional circuitry to alter the magnetic field of the stator elements because it lacks the self-commutation characteristics of brushed electric motors. Furthermore, various methods of field-oriented control (FOC) have been developed to operate the coil elements constituting the stator; see [link to relevant documentation]. Figure 2 The rotor, formed by permanent magnets m1 with opposite magnetic poles N and S, rotates around its axis under the influence of the changing magnetic field of the stator, which is the net sum of the fields of the coil elements L1-L3. The torque experienced by the rotor is then generated by the attraction or repulsion between this net stator field of the coil elements and the magnetic field of the magnets (i.e., the rotor). The net magnetic field of the stator can be decomposed into parallel or direct components I. d Orthogonal or perpendicular to I q The components are related to the orientation of the rotor field. Since only the quadrature component will contribute to the torque, the control coils L1-L3 and their associated magnetic fields are designed to maximize the quadrature component and minimize the direct component. Hence the term field-oriented control.

[0037] For smooth operation of the roof assembly, the torque is preferably constant to maintain continuous movement and speed of the movable panel when opening or closing the roof assembly. However, as mentioned above, the movement of the movable panel may be impeded, resulting in additional load and requiring torque adjustment to maintain continuous speed and movement. Therefore, it is desirable to use the motor speed as feedback in the control system.

[0038] Reference Figure 3An example of a control system for field-oriented control (FOC) is shown. The control system 30 includes a speed controller 31, a current controller 32, and a motor 33. A speed setpoint ω_set is received as input to system 30. The system output can be represented as the motor speed, the current drawn by the motor, and / or the relative position of the motor, such as the angular position of the rotor. The actual measured speed or its estimate, transmitted as the system output, is fed back to the input ω_set via control loop CL1 and used to determine the deviation from the desired speed as a speed error ω_error. Based on this error or deviation signal ω_error, the speed controller 31 can adjust the current setpoint I_set. The system output is also provided to the current setpoint I_set via a second control loop CL2 to determine the current deviation or error signal I_error provided to the current controller 32. Additionally, the system output is provided directly to the current controller 32 as feedback. Based on the signal received via control loop CL2 and the feedback, the current controller 32 applies pulse width modulation (PWM) to drive the motor 33. For example, for a 10A control point, based on the current and voltage from the phase signals delivered to each coil element, a measured current of 9.8A gives an error of 0.2A, which will drive the adjustment to achieve the desired 10A according to the setpoint.

[0039] In order to drive the motor correctly in terms of commutation, the relative position of the rotor and stator needs to be provided to the controller to allow the electronics to adjust the drive signal. As will be understood, this relative position is repeated for each revolution of the motor. This relative position signal pos_comm from motor 43 can be regarded as the commutation signal of current controller 43.

[0040] Such as about Figure 3The described standard field-oriented control (FOC) can be sensorless, thus consisting of a cascaded control with two control loops, CL1 and CL2. The slow outer loop CL1 controls the motor speed based on an external setpoint, such as a motor speed setting of 3500 rpm. The output of this control loop is fed to the current setpoint in the fast inner control loop CL2. This inner control loop controls the motor current and, therefore, indirectly controls the motor's output torque. As an example, if the motor speed is too low, the current setpoint will increase, resulting in an increase in the motor's output torque, which, under the assumption that the load torque remains constant, will accelerate the motor. In reality, the load torque of the movable panel of the roof assembly is not a constant value and can vary during opening and movement. The standard FOC controller will react to such load changes as the motor speed will begin to change. This means that whenever there is a significant load change, it may take some time before each controller reacts to the change, and the speed stabilizes at the setpoint again. If the load change is large enough, it can cause fluctuations in motor speed, leading to deterioration of NVH performance and, in some cases, even unstable controller behavior.

[0041] To improve the performance of the cascaded system described so far, a performance feedforward module 36 can be provided to enhance the response to anticipated changes in load torque, for example, which can be predetermined. Since the movement of the movable panel of the roof assembly on a set of parallel track guides is limited to fixed, known tracks, the load torque along the tracks can be predetermined, for example, based on measurements. For example, the curvature of the roof can increase or decrease the load torque along the tracks. Alternatively or additionally, the current drawn by the motor can be stored, since this can also represent the load. Thus, a position-based (whether measured or estimated) performance curve based on the tracks can be provided as a current signal I_ff to the current controller. And, for example, a current error signal I_error can be further determined. The position estimation signal pos_fb can be delivered as an input to the performance feedforward module 36, for example, via a feedback loop, depending on the system output. In other examples, the position can be delivered via a position detector or another type of sensor.

[0042] Reference Figure 4 Another example of a control system 40 for field-oriented control (FOC) is shown. Control system 40 also includes a speed controller 41, a current controller 42, a motor 43, and a performance feedforward module 46. In this example, the performance feedforward module 46 includes multiple performance curves. Each performance curve may correspond to different operating conditions or different sets of operating conditions. Operating conditions in this document refer to factors affecting load torque, such as temperature T. i Humidity, lifespan, pressure, power P i .

[0043] Furthermore, the control system can be configured to collect and store data acquired over time and update one or more performance curves, and / or it can create new additional performance curves. The collected and / or acquired data is referred to as performance feedback and may include the drawn current as a function of absolute position, the transmitted torque as a function of absolute position, and the corresponding environmental conditions as described above. The data may also include motor speed and / or acceleration. Apart from the more refined performance feedforward modules, the operation of the control system 40 is similar to that described above. Figure 3 The operation.

[0044] Performance curves can be defined in various ways to improve and / or adjust motor performance over time. A performance curve may include the amount of torque required at a position along the track along which the movable panel travels; and associate this with a current feedforward I_ff stored to achieve the specified torque. In a basic manner, the performance curve may simply include the current offset stored for the position along the track along which the movable panel travels. The forwarded current offset then allows adjustment of the current error signal I_error to obtain the speed set by the speed controller. Furthermore, the performance may differ for the closing and opening movements of the movable component.

[0045] As described above, the track of the movable panel, defined by guides or rails, is known in advance and will not change, and the mechanism slidably supports the panel along said guides or rails. This means that the track can be represented by a sequence of absolute positions, as indicated by absolute position signals. This, in turn, allows the storage of the required and / or supplied current, which is stored as a function of the absolute position or position signal, thereby creating performance curves. Each performance curve can be stored for a specific set or combination of conditions, such as vehicle operation or environmental conditions. Thus, the environmental conditions and material properties of the roof assembly can be monitored over time to determine the opening and closing performance of the roof assembly, and stored as corresponding performance curves for specific conditions. Even potential differences in conditions, such as morning and afternoon, can be monitored, and if these result in performance differences, they can be stored for future use as performance curves indicating position-based feedforward signals. In this way, smooth operation of the roof assembly, particularly at a substantially constant speed, can be achieved.

[0046] The addition of a new performance curve can be determined by the occurrence of previously undetected environmental conditions. For conditions similar to those previously detected, the update of an existing performance curve can be determined by detecting an increase in the deviation of the current error signal I_error during operation, or based on the current available from the controller. Preferably, this operation is performed when the same deviation of the performance curve has occurred repeatedly, i.e., when it occurs in multiple instances. This is to prevent responding to isolated, occasional events.

[0047] During movement, the performance curve feedforward controller provides a current feedforward I_ff to the current setpoint I_set based on the absolute position signal. When no data is available for a certain absolute position, the performance curve can determine the current feedforward by interpolating between adjacent available data points. This can be further implemented based on environmental conditions, and even across performance curves.

[0048] To achieve the various functions described herein, the performance curve feedforward modules may need to be able to monitor, collect, and / or receive (additional) data and / or process data. Therefore, the performance curve feedforward modules 36, 46 can be implemented as basic memory registers or lookup tables, as databases, or as processing module controllers equipped with memory resources and capable of performing various computational functions. This depends on the desired level of functionality.

[0049] Reference Figure 5 It shows more details Figure 4 An exemplary embodiment of the control system is described. In this embodiment, the speed controller 41 is implemented as a proportional-integral controller (PI-ctrl) 51. The motor 43 is implemented by a power stage 52 that supplies power to the brushless DC (BLDC) motor 53 driving the gearbox 54. The current controller 42 is implemented by two proportional-integral controllers 58 and 59, which directly control the current of the excitation coil elements. d and orthogonal I q Each component has a proportional-integral controller. To simplify the calculation of the current component for each phase associated with the corresponding coil, the Clarke transform and Park transform are applied (60, 61). These allow the net electric field to be expressed as a direct Ip. d and orthogonal I q Components. Other suitable mathematical transformations can be applied if needed, or none at all when a separate PI controller is applied to the corresponding current for each of the three phases. Therefore, the current feedback I_fb, which includes the current and voltage for each phase, can be transformed. Current component I d I q These currents are fed to the corresponding current setpoints 55 and 56. Since the torque experienced by the rotor depends only on the quadrature component, it may be sufficient to focus the control on this current component. The current feedback I_fb can be obtained from the power stage 52 of the motor 43, for example, by measurement via a sensor (e.g., a shunt resistor). The current controller 42 also includes a pulse width modulator PWM 62 for generating the input signal for the power stage 52 of the motor 43.

[0050] The performance feedforward module 46 is implemented such that it provides only the quadrature Iq component as the current feedforward I_ff, which is delivered to the associated current setpoint 55.

[0051] The control system 50 also includes an observer 57. This observer 57 provides a mathematical model representing the relationship between the I, V values ​​for each phase of the motor input signal and the motor speed and position as output signals. The observer 57 feeds the position of the movable component operated by the motor (i.e., the roof panel or sun visor) to the performance feedforward module 46. The observer 57 also feeds back the motor speed ω_fb to the speed setpoint ω_set as part of the external control loop CL1. The observer also provides the current controller 42 with the motor position, i.e., the relative position of the rotor and stator, to adjust the drive signal as explained. In brushed motors, this is eliminated by their self-commutation characteristics; in brushless motors, this feedback is required. Therefore, this signal can be considered as a commutation signal pos_comm based on the motor position. In other embodiments, the observer may also provide the motor speed ω to the current controller 42 to indicate the beat or frequency of motor operation and the frequency at which current switching across coil elements should occur.

[0052] In the above embodiments, the speed and position of the motor can be derived from the current and voltage of the corresponding phases supplied to the motor 43 (specifically, power stage 52). This enables sensorless operation of the control system. In other embodiments, the required feedback can be derived from a Hall sensor, or it can be derived from an encoder.

[0053] To determine the position of a movable component moving along a known track, an absolute position signal is required, which can be derived, for example, from motor speed and / or revolutions. Known transmission characteristics, such as gearbox ratios, the position of the movable component on the track can be determined from the absolute motor position signal pos_fb. In some embodiments, an observer can be configured to determine the absolute position of the movable component. In other embodiments, a performance feedforward module is configured to determine the absolute position of the movable component. Since the absolute position of the movable component is directly related to the motor, it is sufficient to directly derive the absolute position signal from the motor and use it as a representation of the absolute position of the movable component. Therefore, the performance curve of the set of operating conditions can include a feedforward current as a function of the absolute position, which is the absolute position of the movable component or the motor.

[0054] Reference Figure 6 This illustrates the control operations such as Figure 1A and Figure 1BAn example of a method for a motor in a vehicle roof assembly disclosed herein. The roof assembly includes roof panels 2a, 2b, which are movable between a closed position and an open position via a motor. The motor, as part of a drive assembly, operates the movable panels. The method includes receiving a speed setpoint ω_set as input at 601, feeding back a speed feedback signal ω_fb from the motors (33, 43) to the input ω_set, and determining (602) a speed error ω_error. The speed setpoint will be the default setting desired by the vehicle manufacturer. The speed feedback signal is measured from the motor or derived from known operating current and voltage of the motor. The speed error signal is the difference between the set speed and the speed feedback from the motor, and is an input to a speed controller 41.

[0055] The method includes providing a 603 current setpoint I_set based on a speed error ω_error. A current output I_fb is fed back from motors 33 and 43 to the current setpoint I_set, and a 606 current error signal I_error is determined. The current setpoint indicates the setting associated with a specific torque required to bring the motor to a set speed. The current feedback indicates whether the required torque is delivered.

[0056] This method includes feeding back a relative position signal pos_comm. The relative position signal indicates the rotor's position relative to the stator. And based on the performance curve determined from the absolute position signal pos_fb, a current feedforward signal I_ff is fed forward to the current setpoint I_set.

[0057] The method also includes generating a drive signal 607 for driving motors 33 and 43 based on the current error signal I_error and the motor position signal pos_comm.

[0058] In the above method, the determination of the current error signal I_error is based on the current setpoint I_set, the current feedback I_ff, and the current feedforward I_ff.

[0059] The relative position signal pos_comm indicates the relative position of the rotor relative to the stator. This can be used by a switching circuit as a commutation signal for the coil elements driving the motor. The absolute position signal indicates the absolute position of the motor and / or the movable component on the track driven by the motor, as described above. The performance curve corresponds to at least one corresponding set of operating conditions. The performance curve stores torque and / or current as a function of absolute position and is used to provide current feedforward based on the absolute position of the motor or movable component.

[0060] In some embodiments, regarding Figure 6 The described method can be extended to further include updating the performance curve in response to location-related performance feedback received in response to a corresponding set of operating conditions.

[0061] In some embodiments, regarding Figure 6 The described method can be extended to further include storing another performance curve in response to the detection or receipt of another set of operating conditions.

[0062] This document discloses detailed embodiments of the invention; however, it should be understood that the disclosed embodiments are merely examples of the invention, which can be implemented in various forms. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but rather serve as the basis for the claims and as a representative basis for teaching those skilled in the art to employ the invention differently with any suitably detailed structure contemplated. In particular, features presented and described in the individual dependent claims may be applied in combination, and any advantageous combinations of such claims are disclosed herein.

[0063] Furthermore, it is anticipated that structural elements can be generated by applying three-dimensional (3D) printing technology. Therefore, any reference to a structural element is intended to cover any computer-executable instructions that instruct a computer to generate such a structural element using 3D printing technology or a similar computer-controlled manufacturing technique. Additionally, any such reference to a structural element is also intended to cover a computer-readable medium carrying such computer-executable instructions.

[0064] Furthermore, the terminology and phrases used herein are not intended to be limiting, but rather to provide an understandable description of the invention. As used herein, the term "a" is defined as one or more. The term "plural" as used herein is defined as two or more. As used herein, the term "another" is defined as at least a second or more. As used herein, the term "including" and / or "having" is defined as including (i.e., open-ended language). As used herein, the term "link" is defined as a connection, but not necessarily a direct connection.

[0065] Although the invention has been described above with reference to specific embodiments, it is not intended to be limited to the specific forms set forth herein. Rather, the invention is limited only by the appended claims, and other embodiments besides the specific embodiments described above are also possible within the scope of these appended claims.

[0066] Furthermore, although exemplary embodiments have been described above with respect to some exemplary combinations of components and / or functions, it should be understood that alternative embodiments may be provided by different combinations of components and / or functions without departing from the scope of this disclosure. Additionally, it is particularly contemplated that specific features described individually or as part of an embodiment may be combined with other separately described features or portions of other embodiments.

Claims

1. A control system for operating a motor of a roof assembly, comprising: a speed controller (31, 41); a current controller (32, 42); a motor (33, 43); and a performance feedforward module (36, 46); wherein the control system is configured for: receiving a speed setpoint ω_set as input, feeding back a speed signal ω_fb from the motor (33, 43) to the input ω_set, and determining a speed error ω_error; providing a current setpoint I_set by the speed controller (31, 41) based on the speed error ω_error; feeding back a current output I_fb from the motor (33, 43) to the current setpoint I_set, determining a current error signal I_error, and providing the current error signal I_error to the current controller (32, 42); feeding back a relative position signal pos_comm to the current controller (32, 42); feeding forward a current feedforward signal I_ff to the current setpoint I_set by the performance feedforward module (36, 46) based on an absolute position signal pos_fb; generating a drive signal for driving the motor (33, 43) by the current controller (32, 42) based on the current error signal I_error and the relative position signal pos_comm; and wherein determining the current error signal I_error is based on the current setpoint I_set, a current feedback I_fb, and the current feedforward I_ff.

2. The system according to claim 1, wherein the relative position signal is indicative of a relative position of a rotor and a stator.

3. The system according to claim 1 or 2, wherein the absolute position signal is indicative of an absolute position of the motor and / or a movable member on a track driven by the motor.

4. The system according to any one of the preceding claims, wherein the performance feedforward module (36, 46) comprises at least one performance curve of a respective set of operating conditions.

5. The system according to any one of the preceding claims, wherein the performance feedforward module (36, 46) is configured for storing and / or updating the at least one performance curve in response to receiving a position-dependent performance feedback for a respective set of operating conditions.

6. The system according to any one of the preceding claims, wherein the performance feedforward module (36, 46) is configured for storing another performance curve in response to detecting or receiving another set of operating conditions.

7. The system according to any one of the preceding claims, wherein the performance feedforward module (36, 46) stores torque and / or current as a function of absolute position.

8. A method for controlling a motor of a roof assembly of a vehicle, the roof assembly comprising a roof panel (2a, 2b) movable between a closed position and an open position via the motor, the method comprising: ​ receiving (601) a speed setpoint ω_set as input, feeding back a speed feedback signal ω_fb from the motor to the input ω_set, and determining (602) a speed error ω_error; providing (603) a current setpoint I_set based on the speed error ω_error; feeding back a current output I_fb from the motor to the current setpoint I_set, and determining (606) a current error signal I_error; feeding forward a current feedforward signal I_ff (605) to the current setpoint I_set based on at least one performance curve determined (604) from an absolute position signal pos_fb; generating (607) a drive signal for driving the motor based on the current error signal I_error and the relative position signal pos_comm; and wherein determining (606) the current error signal I_error is based on the current setpoint I_set, a current feedback I_fb, and the current feedforward I_ff.

9. The method according to claim 8, wherein the relative position signal is indicative of a relative position of a rotor and a stator.

10. The method according to claim 8 or 9, wherein the absolute position signal is indicative of an absolute position of the motor and / or a movable member on a track driven by the motor.

11. The method according to any of the preceding claims 8-10, wherein the at least one performance curve corresponds to at least one respective set of operating conditions.

12. The method according to any of the preceding claims 8-11, updating the at least one performance curve in response to receiving position dependent performance feedback for a respective set of operating conditions.

13. The method according to any of the preceding claims 8-12, storing another performance curve in response to detecting or receiving another set of operating conditions.

14. The method according to any of the preceding claims 8-13, wherein the at least one performance curve stores torque and / or current as a function of absolute position.

15. A roof assembly for a vehicle, comprising: a roof panel and / or sun visor (2a, 2b) movable between a closed position and an open position; and a control system according to any of the preceding claims configured for operating the roof panel and / or sun visor to move between the closed position and the open position. ​

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