SYSTEMS AND METHODS FOR CONTROLLING THE POSITION OF A MOVING LIGHT FIXTURE

A moving light fixture and methods for controlling the position of the moving light fixture. The moving light fixture includes a housing, a motor operably coupled to the housing to rotate the housing about an axis of rotation, and an indexer configured to rotate in conjunction with the housing. A magnetic position encoder transmits a first position signal indicating an angular position of the housing, and an optical sensor transmits a second position signal indicating a position of the indexer. An electronic controller receives a target position for the moving light fixture, determines an angular position of the housing based on the first position signal, determines a position of the indexer based on the second position signal, determines a current position of the housing, and drives the motor to move the housing from the current angular position to the target position based on the position of the indexer.

FIELD

Embodiments described herein relate to controlling the position of a moving light fixture.

SUMMARY

Moving light fixtures are often propelled by motors, such as either DC servo motors or stepper motors. DC servo motors provide full positional feedback. Stepper motors are relative position devices that require a known reference position. The pan and tilt axes in a moving light fixture with stepper motors may require homing to a known position on start-up. This homing operation takes time to complete and requires that the moving light fixture has full, unencumbered movement. The homing operation precludes operating the moving light fixture on a tightly packed lighting bar, directing the moving light fixture through a window or aperture, or otherwise operating the moving light fixture with a restricted range of movement. The homing operation also produces an undesirable noise in theatrical environments, especially if re-homing needs to occur during a live production.

Some moving light fixtures with stepper motors address homing operation issues using optical quadrature encoders. However, optical quadrature encoders provide only relative position feedback, not absolute. Magnetic position encoders assist in identifying a quadrant in which the moving light fixture is located. For example, U.S. Pat. No. 10,274,175, incorporated herein by reference, discloses using magnetic position encoders to assist in driving a stepper motor from a current position to a target position. Embodiments described herein further increase the positional accuracy of movement of the light fixture by further implementing a quadrature or optical sensor in combination with a magnetic absolute encoders. For example, a magnetic position encoder approximately identifies a quadrant location of the light fixture. An indexer, such as a gear or notched wheel with tabs, rotates with the light fixture. The quadrature or optical sensor identifies the edge of the nearest tab on the indexer as it turns on the same driven axis. The tab is used to further adjust the position of the light fixture with an additional level of accuracy.

One embodiment provides a moving light fixture including a housing and one or more lights disposed within the housing. The moving light fixture includes a motor operably coupled to the housing such that the motor rotates the housing about an axis of rotation and an indexer configured to rotate in conjunction with the housing along the axis of rotation. The moving light fixture includes a magnetic position encoder configured to transmit a first position signal indicating an angular position of the housing about the axis of rotation, and an optical sensor configured to transmit a second position signal indicating a position of the indexer about the axis of rotation. The moving light fixture includes an electronic controller connected to the motor, the magnetic sensor, and the optical sensor. The electronic controller is configured to receive a target position for the moving light fixture, determine an angular position of the housing about the axis of rotation based on the first position signal, and determine a position of the indexer within the current angular position based on the second position signal. The electronic controller is configured to determine a current position of the housing based on the angular position and the position of the indexer and drive the motor to move the housing from the current angular position to the target position based on the position of the indexer.

Another embodiment provides a method of controlling a position of a moving light fixture, the moving light fixture including one or more light sources disposed within a housing, a motor operably coupled to the housing such that the motor rotates the housing about an axis of rotation, and an indexer configured to rotate in conjunction with the housing along the axis of rotation. The method includes receiving a target position for the moving light fixture, determining, with an electronic controller and based on a first signal from a magnetic position encoder, an angular position of the housing about the axis of rotation, and determining, with the electronic controller and based on a second signal from an optical sensor, a position of the indexer within the angular position. The method includes determining, with the electronic controller, a current position of the housing based on the angular position of the housing about the axis of rotation and the position of the indexer, and driving, with the electronic controller, the motor to move the housing from the current position to the target position.

Another embodiment provides a moving light fixture including a housing and one or more light sources disposed within the housing. The moving light fixture includes a motor operably coupled to the housing such that the motor rotates the housing about an axis of rotation and an indexer configured to rotate in conjunction with the housing along the axis of rotation. The moving light fixture includes a magnetic position encoder configured to transmit a first position signal indicating an angular position of the housing about the axis of rotation and an optical sensor configured to transmit a second position signal indicating a position of the indexer about the axis of rotation. The moving light fixture includes an electronic controller connected to the motor, the magnetic sensor, and the optical sensor. The electronic controller is configured to receive a target position for the moving light fixture, determine an angular position of the housing about the axis of rotation based on the first position signal, and determine a current full step of the motor based on the current angular position. The electronic controller is configured to determine a current position of the indexer within the current angular position based on the second position signal and determine a current micro step of the motor based on the current position of the indexer. The electronic controller is configured to determine a current position of the housing based on the current full step of the motor and the current micro step of the motor, and drive the motor to move the housing from the current position to the target position.

Before any implementations of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other implementations and of being practice or of being carried out in various ways.

Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “mounted,” “connected,” and “coupled” are used broadly and encompass both direct and indirect mounting, connecting, and coupling. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect. Also, electronic communications and notifications may be performed using other known means including direct connections, wireless connections, etc.

It should also be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components, may be utilized to implement the disclosure. Furthermore, and as described in subsequent paragraphs, the specific configurations illustrated in the drawings are intended to exemplify implementations of the disclosure. Alternative configurations are possible.

DETAILED DESCRIPTION

Embodiments described herein relate to systems, methods, and devices for controlling the position of an automated luminaire or moving light fixture. The moving light fixture includes, among other things, one or more light sources (for example, incandescent light sources, LED light sources, etc.), one or more motors, and an electronic controller. The electronic controller is configured to regulate or control the position of the moving light fixture based on full positional feedback. For example, the electronic controller uses the current position of the moving light fixture to determine how to operate the one or more stepper motors to move the light fixture to a target position. However, upon power up, the current position of the moving light fixture is unknown. As such, the electronic controller is configured to determine the absolute position of the moving light fixture.

In some implementations, moving light fixtures are used in, for example, a theatre, a hall, an auditorium, a studio, or the like. Each moving light fixture100includes, among other things, a housing102, one or more light sources104, a frame106, a base108, a first motor110, a second motor112, a first magnetic position encoder114, a second magnetic position encoder116, and an electronic controller122, as illustrated in the embodiment ofFIG.1. The one or more light sources104are disposed (e.g., positioned) within the housing102. The first motor110is operably coupled to the housing102such that the first motor110rotates the housing102about a first axis of rotation124(e.g., a horizontal axis). The second motor112is operably coupled to the housing102such that the second motor112rotates the housing102about a second axis of rotation126(e.g., a vertical axis). In some embodiments, the second axis of rotation126is perpendicular to the first axis of rotation124.

In the example embodiment illustrated inFIG.1, the first motor110is configured to apply torque to a first output shaft128. A first pulley130is mounted on the first output shaft128for rotation together therewith. The first pulley130is coupled to a second pulley132via a first belt134to transfer torque therebetween. The second pulley132is mounted to a first shaft136for rotation together therewith. The first shaft136is fixably coupled to the housing102such that the housing102and the first shaft136rotate together about the first axis of rotation124. The housing102is also fixably coupled to a second shaft138such that the second shaft138, the housing102, and the first shaft136all rotate together about the first axis of rotation124.

In the example embodiment illustrated inFIG.1, the second motor112is configured to apply torque to a second output shaft140. A third pulley142is mounted on the second output shaft140for rotation together therewith. The third pulley142is coupled to a fourth pulley144via a second belt146to transfer torque therebetween. The fourth pulley144is fixably coupled to a third shaft148. The third shaft148is fixably coupled to the base108. In operation, the second motor112applies a torque to the fourth pulley144(via the second output shaft140, the third pulley142, and the second belt146) which causes the frame106to rotate about the second axis of rotation126. The housing102is coupled to the frame106via the first shaft136and the second shaft138such that the housing102rotates with the frame106about the second axis of rotation126. A fourth shaft150is fixably coupled to the frame106such that the fourth shaft150, the frame106, and the housing102all rotate together about the second axis of rotation126. The fourth shaft150partially extends into the base108along the second axis of rotation126. A fifth pulley152is fixably mounted to the fourth shaft150such that the fifth pulley152, the fourth shaft150, the frame106, and the housing102all rotate together about the second axis of rotation126. The fifth pulley152is coupled to a sixth pulley154via a third belt156to transfer torque therebetween.

The first magnetic position encoder114is configured to measure the angular position of the housing102about the first axis of rotation124. The first magnetic position encoder114includes, among other things, a first magnet158and a first magnetic position sensor160. In the example embodiment illustrated inFIG.1, the first magnet158is fixably mounted to an end of the second shaft138such that the first magnet158, the second shaft138, the housing102, and the first shaft136all rotate together about the first axis of rotation124. The first magnetic position sensor160is fixably mounted to the frame106via a first circuit board162. In some embodiments, the first magnet158is fixably mounted to an end of the first shaft136such that the first magnet158, the first shaft136, and the housing102all rotate together about the first axis of rotation124. Alternatively, in some embodiments, the first magnetic position sensor160is fixably mounted to an end of the first shaft136or the second shaft138such that the first magnetic position sensor160, the first shaft136, the second shaft138, and the housing102all rotate together about the first axis of rotation124. In such embodiments, the first magnet158is fixably mounted to the frame106, for example, via the first circuit board162.

The first magnetic position sensor160is positioned adjacent to the first magnet158such that the first magnetic position sensor160measures the angular position of the first magnet158. Rotational movement of the housing102about the first axis of rotation124changes the relative angular position between the first magnet158and the first magnetic position sensor160. Thus, the measured angular position of the first magnet158directly correlates to the angular position of the housing about the first axis of rotation124.

The second magnetic position encoder116is configured to measure the angular position of the housing102about the second axis of rotation126. The second magnetic position encoder116includes, among other things, a second magnet164and a second magnetic position sensor166. In the example embodiment illustrated inFIG.1, the second magnet164is fixably mounted to the sixth pulley154for rotation together therewith. The second magnetic position sensor166is fixably mounted to the base108via a second circuit board168. In some embodiments, the second magnetic position sensor166is fixably mounted to the sixth pulley154for rotation together therewith. In such embodiments, the second magnet164is fixably mounted to the base108, for example, via the second circuit board168.

The second magnetic position sensor166is positioned adjacent to the second magnet164such that the second magnetic position sensor166measures the angular position of the second magnet164. Rotational movement of the housing102about the second axis of rotation126changes the relative angular position between the second magnet164and the second magnetic position sensor166. Thus, the measured angular position of the second magnet164directly correlates to the angular position of the housing about the second axis of rotation126.

As described, the first motor110is operably configured to rotate the housing102about the first axis of rotation124. In some embodiments, rotation about the first axis of rotation124is a tilting motion.FIG.2Ais a side view of the moving light fixture100in which the housing102is positioned at a first angular position on the first axis of rotation124(for example, a reference tilt position).FIG.2Bis a side view of the moving light fixture100after the housing102is rotated about the first axis of rotation124such that the housing102is positioned at a second angular position on the first axis of rotation124. The angle between the first angular position illustrated inFIG.2Aand the second angular position illustrated inFIG.2Bis 65 degrees.

Also, as described above, the second motor112is operably configured to rotate the frame106and the housing102about the second axis of rotation126. In some embodiments, rotation about the second axis of rotation126is a panning motion.FIG.3Ais a top view of the moving light fixture100in which the housing102and the frame106are positioned at a first angular position on the second axis of rotation126(for example, a reference pan position), in accordance with some embodiments.FIG.3Bis a top view of the moving light fixture100after the housing102and the frame106are rotated about the second axis of rotation126such that the housing102and the frame106are positioned at a second angular position on the second axis of rotation126), in accordance with some embodiments. The angle between the first angular position illustrated inFIG.3Aand the second angular position illustrated inFIG.3Bis approximately 80 degrees.

In some instances, the first motor110and the second motor112are brushless DC electric stepper motors that divide a full rotation into a number of equal full steps.FIG.4is one example embodiment of the first motor110configured as a stepper motor. The example embodiment of the first motor110illustrated inFIG.4includes a stator405and a rotor410. The stator405includes, for example, four coils (for example, a first coil415, a second coil420, a third coil425, and a fourth coil430). The rotor410includes, for example, a gear-shaped piece of iron having a plurality of teeth. The four coils415,420,425, and430are selectively energized to make rotor410rotate. For example, the first coil415is energized, which magnetically attracts the teeth of the rotor410. When the teeth of the rotor410are aligned with first coil415, they are slightly offset from second coil420. Thus, when the second coil420is energized and the first coil415is de-energized, the rotor410rotates slightly to align the teeth of the rotor410with the second coil420. Each rotation caused by energizing one of the four coils415,420,425, and430is a full step. In some embodiments, the first motor110includes 200 full steps. With 200 total full steps, each full step equates to approximately 1.8 degrees of rotation.

Instead of energizing one coil at a time with a full pulse of current, the first110can energize two adjacent coils with partial pulses of current. For example, when the first coil415is energized with a pulse of current having an amplitude value of twenty-five percent and the second coil420is energized with a pulse of current having an amplitude value of seventy-five percent, the rotor410rotates to a position that is between two adjacent full steps. In this manner, the first motor110divides each full step into a number of micro steps. The number of micro steps for each full step is set based on the amplitude resolution of the current pulses. In other words, the number of micro steps for each full step is generally equal to the number of different amplitudes values that can be generated. For example, eight bits of resolution equates to current pulses with 256 different amplitude values and, thus, 256 micro steps for each full step. In some embodiments, the first motor110includes 256 micro steps for each full step. With 200 total full steps and 256 micro steps for each full step, each micro step equates to approximately 0.007 degrees of rotation.

In some embodiments, the second motor112includes, among other things, all or a combination of the components described herein as being included in the first motor110.

The first magnetic position sensor160and the second magnetic position sensor166include transducers and/or sensors (for example, hall effect sensors) that vary their output voltages in response to a magnetic field generated by the first magnet158and the second magnet164. The resolution of a rotary position sensor is defined by the number of distinct angular positions that the rotary position sensor can detect per revolution. Resolution is often described in terms of bits. For example, ten bits of resolution equates to 1,024 detectable angular positions per revolution, and twelve bits of resolution equates to 4,096 detectable angular positions per revolution.

FIGS.5A,5B, and5Cillustrate an example of a ten bit magnetic position sensor505that detects the angular position of a test magnet510. The magnetic position sensor505is coupled to a circuit board515. The test magnet510is positioned near the ten bit magnetic position sensor505such that the ten bit magnetic position sensor505detects the magnetic field generated by the test magnet510. However, as illustrated inFIG.5A, the test magnet510is separated from the ten bit magnetic position sensor505by a short distance. The distance between the magnetic position sensor505and the test magnet510may be, for example, between approximately 0.2 millimeters and 2 millimeters. The ten bit magnetic position sensor505measures the angular position of the test magnet510and determines an integer value between zero and 1,023 that corresponds to the detected angular position of the test magnet510. The determined integer value may be displayed on a display520that is also coupled to the circuit board515. For example, inFIG.5B, the test magnet510is positioned at a first angular position and the display520displays a determined integer value of 358.FIG.5Cillustrates the test magnet510after the test magnet510has been moved from the first angular position to a second angular position. The display520isFIG.5Cdisplays a determined integer value of 572 for the second angular position. In some embodiments, the first magnetic position encoder114and the second magnetic position encoder116include a ten bit magnetic position sensor (such as the ten bit magnetic position sensor505described above).

The first magnetic position sensor160measures the angular position of the first magnet158and generates a position signal indicating the measured angular position of the first magnet158. As rotational movement between the first magnet158and the first magnetic position sensor160mirrors the rotational movement of the housing102about the first axis of rotation124, the position signal also indicates the angular position of the housing102about the first axis of rotation124. In some embodiments, the position signal includes a digital value indicating the measured angular position of the first magnet158. For example, for when the first magnetic position sensor160includes a ten bit magnetic position sensor (such as the ten bit magnetic position sensor505described above), the position signal can include a digital integer value between zero and 1,023. Alternatively or in addition, the position signal includes a pulse width modulated (PWM) signal in which the duty cycle indicates the measured angular position of the first magnet158. For example, a ten percent duty cycle may indicate that the measured angular position of the first magnet158is 36 degrees and a five percent duty cycle may indicate that the measured angular position of the first magnet158is 18 degrees. In some embodiments, the first magnetic position sensor160outputs the absolute angular position of the first magnet158as a ten-bit value over a serial data link.

The second magnetic position sensor166measures the angular position of the second magnet164and generates a position signal indicating the measured angular position of the second magnet164. As rotational movement between the second magnet164and the second magnetic position sensor166mirrors the rotational movement of the housing102about the second axis of rotation126, the position signal also indicates the angular position of the housing102about the second axis of rotation124. In some embodiments, the position signal generated by the second magnetic position sensor166is similar to the position signal generated by the first magnetic position sensor160described above.

In some instances, in addition to the first magnetic position sensor160, the moving light fixture100further includes an indexer to further detect the angular position of the housing102.FIG.6illustrates an example indexer600. The example indexer600includes a plurality of tabs610(such as a first tab610A, a second tab610B, and a third tab610C). In some instances, the indexer600is coupled to the second shaft138such that the indexer600rotates with the second shaft138. In other instances, the indexer600is coupled to the first shaft136such that the indexer600rotates with the first shaft136.

The indexer600includes an optical sensor605to determine a position of the indexer600based on the plurality of tabs610. For example, as the plurality of tabs610rotate past the optical sensor605, the optical sensor605determines an angular position of the second shaft138, and therefore an angular position of the housing102.FIGS.7A-7Cillustrate example positions of the plurality of tabs610detected by the optical sensor605, in accordance with some embodiments. The optical sensor605includes a sensor center705. The tab610includes a tab center710. In the example ofFIGS.7A-7C, the position of a respective tab610is determined relative to the optical sensor605. For example,FIG.7Aillustrates the tab610at a first angular position where the sensor center705and the tab center710are separated by an angle of a.FIG.7Billustrates the tab610at a second angular position where the sensor center705and the tab center710are substantially aligned (e.g., separated by an angle of approximately 0).FIG.7Cillustrates the tab610at a third angular position where the sensor center705and the tab center710are separated by an angle of (3. In some instances, each tab610further includes a unique identifier such that the optical sensor605identifies which tab610is being observed.

WhileFIG.6illustrates an indexer600configured as a wheel having a plurality of tabs610, other implementations of the indexer600may be considered. For example, the indexer600may be configured as a printed film having a pattern in place of (or, in addition to) the plurality of tabs610. The sensor605provides a signal indicative of a position of the pattern. In another example, the indexer600includes a magnetic film having a varying magnetic characteristic. In such an instance, rather than an optical sensor, sensor605may be configured as a magnetic sensor (e.g., a hall effect sensor) configured to detect the magnetic field of the magnetic film and provide a signal indicative of a position of the magnetic film.

FIG.8illustrates the indexer600situated within the housing102, in accordance with some embodiments. As previously stated, the indexer600may be coupled to the second shaft138such that the indexer600rotates about the first axis of rotation124in conjunction with the second shaft138(and therefore in conjunction with the housing102). In some instances, the moving lighting fixture100includes a second indexer (not shown) coupled to the third shaft148. Accordingly, the second indexer rotates about the second axis of rotation126in conjunction with the third shaft148(and therefore in conjunction with the housing102). In such an implementation, a second optical sensor (not shown) is provided to detect a position of the second indexer. In some embodiments, the second indexer is instead coupled to the second output shaft140or the fourth shaft150.

Movement of the housing102is controlled based on signals from the first magnetic position sensor160, the second magnetic position sensor166, the optical sensor605, and a second optical sensor950.FIG.9is an example of a control system900for the moving light fixture100. The example illustrated inFIG.9includes the one or more light sources104, the first motor110, the second motor112, the first magnetic position encoder114, the second magnetic position encoder116, the first optical sensor605, a second optical sensor950, the electronic controller122, a transceiver925, a user interface930, and a power supply module935.

The electronic controller122includes a plurality of electrical and electronic components that provide power, operational control, and protection to the components and modules within the moving light fixture100. The electronic controller122illustrated inFIG.9includes, among other things, an electronic processor910(for example, a microprocessor, a microcontroller, or another suitable programmable device), memory915, and an input/output interface920. The electronic processor910, the memory915, the input/output interface920, as well as the various modules connected to the electronic controller122are connected by one or more control and/or data buses (for example, a common bus). The control and/or data buses are shown generally inFIG.9for illustrative purposes. The input/output interface920includes routines for transferring information between components within the electronic controller122and other components of the control system900. In some implementations, the electronic controller122is implemented partially or entirely on a semiconductor (for example, a field-programmable gate array [“FPGA”] semiconductor) chip.

The memory915includes, for example, read-only memory (ROM), random access memory (RAM) (for example, dynamic RAM [DRA<], synchronous DRAM [SDRAM], etc.), electronically erasable programmable read-only memory (EEPROM), flash memory, a hard disk, an SD card, other non-transitory computer-readable media, or a combination thereof. The electronic processor910is connected to the memory915and executes software instructions that are capable of being stored in a RAM of the memory915(for example, during execution), a ROM of the memory915(for example, on a generally permanent basis), or another non-transitory computer readable medium such as another memory or a disc. Alternatively or in addition, the memory915is included in the electronic processor910. Software included in some implementations of the moving light fixture100can be stored in the memory915of the electronic controller122. The software includes, for example, firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. The electronic processor910is configured to retrieve program instructions and data from the memory915for generating necessary control signals for the first motor110and the second motor112that are required to drive the motors to move the moving light fixture100to a desired position. In other constructions, the electronic controller122includes additional, fewer, or different components.

The transceiver925transmits and/or receives signals to and/or from one or more separate communication modules in other components of a lighting system (for example, a control board, other light fixtures, etc.). Signals may include, for example, information, data, serial data, data packets, analog signals, or a combination thereof. The transceiver925can be coupled to one or more separate transceivers via wires, fiber, wirelessly, or a combination thereof. Communication via wires, fiber, or both can be any appropriate network topology known to those skilled in the art, such as Ethernet. Wireless communication can be any appropriate wireless network topology known to those skilled in the art, such as Wi-Fi, ZigBee®, Bluetooth®, and the like. In some embodiments, the transceiver925includes separate transmitters and receivers.

The user interface930is included to control the moving light fixture100or the operation of a lighting system as a whole. The user interface930is operably coupled to the electronic controller122to control, for example, the position of the moving light fixture100. The user interface930can include any combination of digital and analog input devices required to achieve a desired level of control for the system. For example, the user interface930can include a computer having a display and input devices, a touch-screen display, a plurality of knobs, dials, switches, buttons, faders, or the like. In some constructions, the user interface930is separated from the moving light fixture100.

The power supply modules935supplies a nominal AC or DC voltage to the moving light fixture100, or a system of moving light fixtures. The power supply modules935is powered by a mains power having nominal line voltages between, for example, 100 Volt and 240 Volt AC and frequencies of approximately 50 Hertz to 60 Hertz. The power supply module935is also configured to supply lower voltages to operate circuits and components within the moving light fixture100. Alternatively or in addition, the moving light fixture100is powered by one or more batteries or battery packs.

The electronic controller122controls the position of the moving light fixture100via the first motor110and the second motor112. The electronic controller122is operably coupled to the first motor110and to the second motor112to provide one or more control signals thereto. In some embodiments, the control signals are modulated current pulses that are generated internally by the first motor110and the second motor112.

As described above, the first motor110and the second motor112are controlled according to both full steps and micro steps based on how the first coil415and the second coil420are energized. Upon start-up the electronic controller122does not know the current full step and current partial (or micro) step of the first motor110and the second motor112. As described herein, the first magnet158(or the first magnetic position sensor160) is operably coupled to the housing102such that it rotates with the housing102about the first axis of rotation124. Thus, the measured angular position of the first magnet158mirrors the angular position of the rotor410in the first motor11. By measuring the angular position of the first magnet158with the first magnetic position sensor160, the electronic controller122determines the current full step of the first motor110. In a similar manner, the electronic controller122determines the current full step of the second motor112by measuring the angular position of the second magnet164with the second magnetic position sensor166.

Additionally, as described herein, the indexer600is operably coupled to the second shaft138such that the indexer600rotates with the housing102about the first axis of rotation124. Thus, by measuring the position of the indexer600with the first optical sensor605, the electronic controller122determines the current micro step of the first motor110. In a similar manner, the electronic controller122determines the current micro step of the second motor112by determining the position of a second indexer (not shown) with the second optical sensor950.

The resolution of the first magnetic position encoder114is greater than the full step resolution of the first motor110such that the first magnetic position encoder114can measure multiple angular positions of the first magnet158for each full step of the first motor110. For example, if the first magnetic position encoder114includes ten bits of resolution and the first motor110includes two-hundred full steps, the first magnetic position encoder114is able to measure approximately fifty-one distinct angular positions of the first magnet158for each full step of the first motor110. Similarly, the resolution of the second magnetic position encoder116is greater than the full step resolution of the second motor112such that the second magnetic position encoder116can measure multiple angular positions of the second magnet164for each full step of the second motor112.

In some instances, the electronic controller122determines the absolute position of the moving light fixture100based in part on the current full step of the first motor110, the current micro step of the first motor110, the current full step of the second motor112, the current micro step of the second motor112, or a combination thereof. With the knowledge of the current absolute position of the moving light fixture100, the electronic controller122is able to determine the number of both full steps and micro steps to rotate the first motor110, the second motor112, or both to adjust the moving light fixture100from its current position to a new position (for example, a target position).

FIG.10illustrates an example method1000for controlling the position of the moving light fixture100about a single axis of rotation. For brevity, the method1000is described in terms of controlling the position of the moving light fixture100about the first axis of rotation124(i.e., tilting movements). However, the same or a similar method may also be used to control the position of the moving light fixture100about the second axis of rotation126(i.e., panning movements). The steps of the method1000are described in an iterative manner for descriptive purposes. Various steps described herein with respect to the method1000are capable of being executed simultaneously, in parallel, or in an order that differs from the illustrated serial and iterative manner of execution.

At block1005, the electronic controller122receives a target position for the moving light fixture100. In some embodiments, the target position includes a desired angle of rotation of the housing102about the first axis of rotation124with respect to a predetermined reference position. For example, the target position can indicate a desired angle of approximately 45 degrees away from the reference position about the first axis of rotation124. Alternatively or in addition, the target position includes a numerical value that corresponds to a desired angle of rotation of the housing102about the first axis of rotation124with respect to a predetermined reference position. For example, a target position of 3 on a scale between 1 and 10 may indicate a desired angle of approximately 45 degrees away from the reference position about the first axis of rotation124. In some embodiments, the electronic controller122receives the target position via the user interface930. For example, a user inputs the target position via buttons included in some embodiments of the user interface930. Alternatively or in addition, the electronic controller122receives the target position via the transceiver625. For example, the electronic controller122receives the target position via the transceiver625from a central control board in a theater.

At block1010, the electronic controller122determines a current angular position of the housing102about the first axis of rotation124. For example, the first magnetic position sensor160transmits a signal indicative of the measured angular position of the first magnet158to the electronic controller122. The electronic controller122determines the angular position of the housing102about the first axis of rotation124based on the received position signal. Alternatively or in addition, the first magnetic position encoder114determines the angular position of the housing about the first axis of rotation124and transmits the angular position to the electronic controller122. In some examples, the angular position of the housing102is determined as a degree value between, for example, zero degrees and 360 degrees. In other examples, the angular position of the housing102is determined as a numerical value in a range of detectable angular positions. For example, the determined angular position of the housing102can be an integer value between zero and 1,024 when the first magnetic position sensor160includes ten bits of resolution.

At block1015, the electronic controller122determines a current position of the indexer600. For example, the first optical sensor605transmits a signal to the electronic controller122indicative of a position of a tab610. The electronic controller122determines the current position of the indexer600based on the position of the tab610. In some examples, the current position of the indexer600is determined as a degree value between, for example, zero degrees and 360 degrees. In other examples, the current position of the indexer600is determined as a numerical value in a range of detectable indexer positions.

At block1020, the electronic controller122drives the first motor110to move the housing102to the target position from the current angular position and based on the position of the indexer600. For example, the electronic controller122drives the first motor110according to full steps based on the determined current angular position of the housing102to rotate the housing to the target position. The electronic controller122then drives the first motor110according to micro steps based on the current position of the indexer600. The first motor110may be driven either clockwise or counter-clockwise to achieve the target position. Accordingly, the electronic controller122uses the position of the indexer600to precisely drive the first motor110.

FIG.11illustrates another example method1100for controlling the position of the moving light fixture100. For brevity, the method1000is described in terms of controlling the position of the moving light fixture100about the first axis of rotation124(i.e., tilting movements). However, the same or a similar method may also be used to control the position of the moving light fixture100about the second axis of rotation126(i.e., panning movements). The steps of the method1100are described in an iterative manner for descriptive purposes. Various steps described herein with respect to the method1100are capable of being executed simultaneously, in parallel, or in an order that differs from the illustrated serial and iterative manner of execution.

At block1105, the electronic controller122receives a target position for the moving light fixture100. In some embodiments, the target position includes a desired angle of rotation of the housing102about the first axis of rotation124with respect to a predetermined reference position. For example, the target position can indicate a desired angle of 45 degrees away from the reference position about the first axis of rotation124. Alternatively or in addition, the target position includes a numerical value that corresponds to a desired angle of rotation of the housing102about the first axis of rotation124with respect to a predetermined reference position. For example, a target position of 3 on a scale between 1 and 10 may indicate a desired angle of 45 degrees away from the reference position about the first axis of rotation124. In some embodiments, the electronic controller122receives the target position via the user interface930. For example, a user inputs the target position via buttons included in some embodiments of the user interface930. Alternatively or in addition, the electronic controller122receives the target position via the transceiver625. For example, the electronic controller122receives the target position via the transceiver625from a central control board in a theater.

At block1110, the electronic controller122determines a current angular position of the housing102about the first axis of rotation124. For example, the first magnetic position sensor160transmits a signal indicative of the measured angular position of the first magnet158to the electronic controller122. The electronic controller122determines the angular position of the housing102about the first axis of rotation124based on the received position signal. Alternatively or in addition, the first magnetic position encoder114determines the angular position of the housing about the first axis of rotation124and transmits the angular position to the electronic controller122. In some examples, the angular position of the housing102is determined as a degree value between, for example, zero degrees and 360 degrees. In other examples, the angular position of the housing102is determined as a numerical value in a range of detectable angular positions. For example, the determined angular position of the housing102can be an integer value between zero and 1,024 when the first magnetic position sensor160includes ten bits of resolution.

At block1115, the electronic controller122determines a current full step of the first motor110based on the angular position of the housing102about the first axis of rotation124. Each full step of the first motor110maps to a range of angular positions of the housing102. In some embodiments, a mapping between the detectable angular position of the housing102and the full steps of the first motor110are included in a look up table stored, for example, in the memory915. In such embodiments, the electronic controller122uses the look up table to determine the full step of the first motor110that maps to the angular position of the housing102detected by the first magnetic position encoder114. For example, an angular position of 18 degrees for the housing102(or a numerical value of 51 on a ten bit scale) maps to the tenth full step of the first motor110, and the angular position of 36 degrees for the housing102(or a numerical value of 102 on a ten bit scale) maps to the twentieth full step of the first motor110.

At block1120, the electronic controller122determines a current position of the indexer600. For example, the first optical sensor605transmits a signal to the electronic controller122indicative of a position of a tab610. The electronic controller122determines the current position of the indexer600based on the position of the tab610. In some examples, the current position of the indexer600is determined as a degree value between, for example, zero degrees and 360 degrees. In other examples, the current position of the indexer600is determined as a numerical value in a range of detectable indexer positions.

At block1125, the electronic controller122determines a current micro step of the first motor110based on the current position of the indexer600. Each micro step of the first motor110maps to a position of the indexer600(e.g., a position of the plurality of tabs610). In some embodiments, a mapping between the position of the indexer600and the micro steps of the first motor110are included in a look up table stored, for example, in the memory915. In such embodiments, the electronic controller122uses the look up table to determine the micro step of the first motor110that maps to the position of the indexer600detected by the first optical sensor605.

At block1130, the electronic controller122determines the current position of the moving light fixture100based in part on the current full step and the current micro step of the first motor110. In some embodiments, the current position is an angle. For example, if the full step of the first motor110is designated by SFulland the micro step of the first motor110is designated by SMicro, the current position, P, of the moving light fixture can be calculated as shown below in EQN 1. EQN 1 can be used to calculate the angular position of the moving light fixture100.

For example, the electronic controller122determines that the current position of the moving light fixture100is 41.778 degrees when the current full step is 23 and the current micro step is 45 (i.e., (23×1.8°)+(54×0.007°)=41.778°).

At block1135, the electronic controller122drives the first motor110to move the moving light fixture100from the current position to the target position. In some embodiments, the electronic controller122sends one or more control signals to the first motor110to change the current full step and the current micro step of the first motor110to a target full step and micro step that corresponds to the received target position of the moving light fixture100. In some embodiments, the one or more control signals include a plurality of current pulses which cause the full step and the micro step of the first motor110to change from their current values to the target values. Alternatively or in addition, the one or more control signals indicate the number of full steps the first motor110should move, the direction of the movement (for example, clockwise or counter-clockwise), and the target micro step. For example, the one or more control signals may indicate that the first motor110should move 37 full steps and 100 micro steps in a clockwise direction.

FIG.12illustrates an example method1200for controlling the position of the moving light fixture100about two different axes of rotation. The method1200is described in terms of controlling the position of the moving light fixture100about the first axis of rotation124and the second axis of rotation126(i.e., tilting movements and panning movements). The steps of method1200are described in an iterative manner for descriptive purposes. Various steps described herein with respect to the method1200are capable of being executed simultaneously, in parallel, or in an order that differs from the illustrated serial and iterative manner of execution.

At block1205, the electronic controller122receives a target position of the moving light fixture100. In some embodiments, the target position includes a desired angle of rotation of the housing102about the first axis of rotation124with respect to a predetermined reference position, a desired angle of rotation of the housing102about the second axis of rotation126with respect to a predetermined reference position, or both. At block1210, the electronic controller122determines a current angular position of the housing102about the first axis of rotation124(for example, a first angular position). At block1215, the electronic controller122determines an angular position of the housing102about the second axis of rotation126(for example, a second angular position).

At block1220, the electronic controller122determines the current full step of the first motor110and the second motor112. For example, the electronic controller122determines the current full step of the first motor110based on the angular position of the housing102about the first axis of rotation124. The electronic controller122also determines the current full step of the second motor112based on the angular position of the housing102about the second axis of rotation126.

At block1225, the electronic controller122determines a current position of the first indexer600with respect to a predetermined reference position. For example, the first optical sensor605transmits a signal to the electronic controller122indicative of a position of a tab610. The electronic controller122determines the current position of the indexer600based on the position of the tab610. At block1830, the electronic controller122determines a current position of the second indexer with respect to a predetermined reference position. For example, the second optical sensor950transmits a signal to the electronic controller122indicative of a position of a second tab. The electronic controller122determines the current position of the second indexer based on the position of the second tab.

At block1235, the electronic controller122determines the current micro step of the first motor110and the second motor112. For example, the electronic controller122determines the current micro step of the first motor110based on the position of the first indexer600. The electronic controller122also determines the current micro step of the second motor112based on the position of the second indexer. At block1240, the electronic controller122drives the first motor110, the second motor112, or both to move the housing102to the target position.

Aside from moving the moving light fixture100in response to receiving a target position, the electronic controller122can move the moving light fixture100to restore it to a target position when the moving light fixture100is hit by an object or hits an object. For example, the moving light fixture100may hit a piece of nearby scenery while moving to a target position. As a further example, the moving light fixture100may be hit by a nearby object while the moving light fixture100is positioned at a target position. In some embodiments, in the manner described herein, the electronic controller122detects the current position of the moving light fixture100continuously or periodically based on the measured angular position from the first magnetic position encoder114, the measured angular position from the second magnetic position encoder116, the current position of the indexer600as measured by the first optical sensor605, the current position of the second indexer as measured by the second optical sensor950, or a combination thereof. Responsive to detecting an unplanned change in position, the electronic controller122may use the newly determined position of the moving light fixture100to drive the first motor110and the second motor112to move the moving light fixture100to the target position.

Thus, embodiments described herein provide, among other things, a moving light fixture and a method for controlling the position of the moving light fixture. Various features and advantages are set forth in the following claims.