System and method for using an industrial manipulator for atmospheric characterization lidar optics positioning

A system includes a light detection and ranging (LiDAR) unit comprising an atmospheric characterization transceiver module. The LiDAR unit is configured to transmit light into an external interaction air region, and collect scattered portions of the transmitted light from the external interaction air region. A robotic arm is operatively coupled to the atmospheric characterization transceiver module. A processor is in operative communication with the robotic arm. The processor is configured to control the robotic arm to position and point the atmospheric characterization transceiver module in a direction of interest to interrogate the external interaction air region.

BACKGROUND

Light detection and ranging (LiDAR) systems interrogate a volume of space (air or other mediums) or an area of a surface by pointing or transmitting an optical beam towards this volume or surface, and then collecting or receiving the reflected or scattered photons. The volume or area interrogated by a LiDAR system is defined by the direction of the transmit and receive optics. To expand on this interrogation volume or area is not a trivial matter.

Scanning the transmit and receive optics at different angles and positions can increase or change the LiDAR interrogation volume or area. However, this approach is challenging due to the cost, reliability, performance tradeoffs, and manufacturability of the scanning mechanism. Due to the high optical performance of LiDAR systems, the optical alignment, optical losses, and timing need to be optimized and preserved through the scanning motion. As a result, there are design tradeoffs that need to be made based on the LiDAR application and user.

SUMMARY

A system includes a light detection and ranging (LiDAR) unit comprising an atmospheric characterization transceiver module. The LiDAR unit is configured to transmit light into an external interaction air region, and collect scattered portions of the transmitted light from the external interaction air region. A robotic arm is operatively coupled to the atmospheric characterization transceiver module. A processor is in operative communication with the robotic arm. The processor is configured to control the robotic arm to position and point the atmospheric characterization transceiver module in a direction of interest to interrogate the external interaction air region.

DETAILED DESCRIPTION

In the following detailed description, embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that other embodiments may be utilized without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense.

A system and method for using an industrial manipulator for atmospheric characterization light detection and ranging (LiDAR) optics positioning are disclosed. The present system and method are intended to solve the challenges of scanning a high-powered LiDAR system with large receive optics. In general, the system uses an automatic manipulator, such as a robotic arm, to position, scan, and point a LiDAR transceiver (transmitter and receiver), without the use of conventional mirrors and scanners.

In one embodiment, a robotic arm is operatively coupled to a LiDAR atmospheric characterization transceiver module. By extending and aiming the robotic arm in the direction of interest, the transceiver module can interrogate a volume of air in the pointing direction. The robotic arm has multiple degrees of freedom, allowing the transceiver module to be pointed in any direction. The extra degrees of freedom allow the transceiver module to be translated and/or rotated in specific configurations or on a selected path/plane or on a selected vector.

The system can repurpose off-the-shelf industrialization tooling equipment to replace expensive and custom designed scanners. When used, the off-the-shelf equipment can reduce the cost and schedule of manufacture, simplify system design, and simplify service and operation of the system. For example, in the use of a robotic arm to point and scan an atmospheric characterization LiDAR transceiver, the robotic arm replaces a two axis (elevation and azimuth) scanner that uses costly, high performance mirrors to direct optical signals.

Using the robotic arm, with several additional degrees of freedom compared to the two axes of scanning of conventional scanners, enables a wide range of stability functions and new operational possibilities. For example, the robotic arm enables easy stowing and securing of the LiDAR system; enables adaptive feedback to increase pointing stability; increases optical head reach and thus simplifies installation or tear down; and increases operational environmental ranges.

In addition, the robotic arm can be used to actively track an object in the atmosphere. When the robotic arm is installed on a platform that also includes a weapon system, such as on a military vehicle, the robotic arm can be used to track the weapon system so that the LiDAR and weapon system are always pointed in the same direction.

The present approach has several technical benefits, including decreasing optical losses due to the elimination of mirrors; reducing the number of optical alignments; better point stability and accuracy; higher environmental robustness; simplification of system integration; and potential reduction of system footprint. Other advantages of the present approach include reduced cost and procurement lead time; simplification of servicing and maintenance; and use of off-the-shelf components with multiple possible suppliers, reducing the risk of obsolescence.

Further details of various embodiments are described hereafter with reference to the drawings.

FIG.1illustrates a positioning apparatus100for LiDAR atmospheric characterization, according to one embodiment. The positioning apparatus100includes a housing110that has a removable cover112. A LiDAR system120is located in housing110and generally includes an atmospheric characterization transceiver module, which includes a laser transmitter and a set of light collection optics. A robotic arm130is mounted within housing110and is operatively coupled to LiDAR system120. An umbilical cord134is coupled to the transceiver module and can run along robotic arm130to any stationary supporting equipment. The umbilical cord134provides power, optical seeding, cooling, and other communication signals to the transceiver module.FIG.1shows a stowed position of LiDAR system120within housing110, with cover112closed.

FIG.2illustrates positioning apparatus100in a measurement position for LiDAR system120. In the measurement position, after cover112is opened, robotic arm130extends and positions LiDAR system120such that the transceiver module transmits light122into an external interaction air region140and collects a scattered portion124of the transmitted light.

When the robotic arm is installed on a moving or unstable platform, such as on a vehicle (e.g., ground vehicle, aerial vehicle, water vehicle), the robotic arm can be used to stabilize the pointing direction or location of the LiDAR system with the help of an inertial measurement unit (IMU) located on the vehicle and a processor, to provide active stabilization.FIG.3is a process flow diagram of a method300for active stabilization, according to one implementation.

The method300first performs a system initialization (block310), after which the IMU measures orientation and velocity in body axes coordinates (block320). A processor then calculates a required robot arm position to maintain pointing of the LiDAR beam (block330), using the measurements from the IMU. The processor then sends commands to the robot arm to move to the calculated new position (block340). The method300then repeats starting at block320to provide an adaptive feedback for maintaining active stabilization of the LiDAR system.

FIG.4is a block diagram of a system400, which includes active LiDAR stabilization for a vehicle402, according to one embodiment. The system400comprises a LiDAR unit410that includes an optical transceiver412, and a robotic arm420operatively coupled to LiDAR unit410. The robotic arm420is mounted to vehicle402and is operative to move LiDAR unit410into multiple different positions and orientations. An inertial measurement unit (IMU)430is deployed on vehicle402and is configured to generate inertial data for vehicle402. A processor unit440onboard vehicle402is in operative communication with IMU430.

The processor unit440is operative to receive and process the inertial data, including orientation and velocity measurements of vehicle402in body axes coordinates, from IMU430(block442). The processor unit440calculates a required position for robotic arm420(block444), to maintain pointing of a beam from optical transceiver412in a direction of interest, based on the measurements from IMU430. The processor unit440then sends commands to robotic arm420(block446), so that robotic arm420moves to the required position based on the calculations. The foregoing steps can be repeated starting at block442to provide an adaptive feedback for maintaining active LiDAR stabilization.

A computer or processor used in the present system and method can be implemented using software, firmware, hardware, or any appropriate combination thereof, as known to one of skill in the art. These may be supplemented by, or incorporated in, specially-designed application-specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). The computer or processor can also include functions with software programs, firmware, or other computer readable instructions for carrying out various process tasks, calculations, and control functions used in the present system and method.

The present method can be implemented by computer executable instructions, such as program modules or components, which are executed by at least one processor. Generally, program modules include routines, programs, objects, data components, data structures, algorithms, and the like, which perform particular tasks or implement particular abstract data types.

Instructions for carrying out the various process tasks, calculations, and generation of other data used in the operation of the method described herein can be implemented in software, firmware, or other computer- or processor-readable instructions. These instructions are typically stored on any appropriate computer program product that includes a computer readable medium used for storage of computer readable instructions or data structures. Such a computer readable medium can be any available media that can be accessed by a general purpose or special purpose computer or processor, or any programmable logic device.

Suitable processor-readable media may include storage or memory media such as magnetic or optical media. For example, storage or memory media may include conventional hard disks, compact discs, DVDs, Blu-ray discs, or other optical storage media; volatile or non-volatile media such as Random Access Memory (RAM); Read Only Memory (ROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, and the like; or any other media that can be used to carry or store desired program code in the form of computer executable instructions or data structures.

Example Embodiments

Example 1 includes a system comprising: a light detection and ranging (LiDAR) unit comprising an atmospheric characterization transceiver module, the LiDAR unit configured to transmit light into an external interaction air region, and collect scattered portions of the transmitted light from the external interaction air region; a robotic arm operatively coupled to the atmospheric characterization transceiver module; and a processor in operative communication with the robotic arm, the processor configured to control the robotic arm to position and point the atmospheric characterization transceiver module in a direction of interest to interrogate the external interaction air region.

Example 2 includes the system of Example 1, wherein the atmospheric characterization transceiver module includes a laser transmitter and a set of light collection optics.

Example 3 includes the system of any of Examples 1-2, wherein the system is installed on a movable or unstable platform.

Example 4 includes the system of Example 3, wherein the platform comprises a vehicle.

Example 5 includes the system of any of Examples 3-4, wherein the platform includes an inertial measurement unit (IMU) operatively coupled to the processor.

Example 6 includes the system of Example 5, wherein the processor is operative to provide an active stabilization of the LiDAR unit using the IMU.

Example 7 includes the system of Example 6, wherein the processor is operative to: (a) receive IMU measurements comprising orientation and velocity in body axes coordinates; (b) calculate a required position for the robotic arm to maintain pointing of the transceiver module in the direction of interest; (c) send commands to the robotic arm to move to the calculated required position; and (d) repeat the previous steps starting at step (a) to provide an adaptive feedback for maintaining the active stabilization of the LiDAR unit.

Example 8 includes the system of any of Examples 1-7, further comprising a housing having a removable cover, the housing configured to store the LiDAR unit in a stowed position with the cover closed.

Example 9 includes the system of Example 8, wherein the removable cover is configured to open, allowing the robotic arm to extend and position the LiDAR unit in a measurement position.

Example 10 includes a system comprising: a LiDAR unit onboard a vehicle and comprising an optical transceiver module, the LiDAR unit configured to transmit light into an external interaction air region, and collect scattered portions of the transmitted light from the external interaction air region; a robotic arm mounted to the vehicle and operatively coupled to the LiDAR unit, the robotic arm operative to move the LiDAR unit into multiple different positions and orientations; an IMU deployed on the vehicle and operative to generate inertial data for the vehicle; and a processor unit onboard the vehicle, the processor unit in operative communication with the IMU and the robotic arm, wherein the processor unit is operative to: (a) receive and process the inertial data from the IMU, the inertial data comprising orientation and velocity measurements of the vehicle in body axes coordinates; (b) calculate a required position for the robotic arm, based on the inertial data from the IMU, to maintain pointing of the optical transceiver module in a direction of interest; (c) send commands to the robotic arm to move to the calculated required position; and (d) repeat the previous steps starting at step (a) to provide an adaptive feedback for maintaining active stabilization of the LiDAR unit.

Example 11 includes the system of Example 10, further comprising a housing having a removable cover, the housing configured to store the LiDAR unit in a stowed position with the cover closed.

Example 12 includes the system of Example 11, wherein the removable cover is configured to open, allowing the robotic arm to extend and position the LiDAR unit in a measurement position.

Example 13 includes the system of any of Examples 10-12, wherein the vehicle is a ground vehicle.

Example 14 includes the system of any of Examples 10-12, wherein the vehicle is an aerial vehicle.

Example 15 includes the system of any of Examples 10-12, wherein the vehicle is a water vehicle.

Example 16 includes a method comprising: (a) providing a LiDAR unit comprising an optical transceiver module, and a robotic arm operatively coupled to the LiDAR unit, the robotic arm mounted on a vehicle; (b) receiving inertial data from an IMU onboard the vehicle, the inertial data comprising orientation and velocity measurements of the vehicle in body axes coordinates; (c) calculating a required position for the robotic arm, based on the inertial data from the IMU, to maintain pointing of the optical transceiver module in a direction of interest; and (d) sending commands to the robotic arm to move to the calculated required position.

Example 17 includes the method of Example 16, further comprising: (d) repeating the method starting at step (b) to provide an adaptive feedback for maintaining active stabilization of the LiDAR unit.

Example 18 includes the method of any of Examples 16-17, wherein the vehicle is a ground vehicle.

Example 19 includes the method of any of Examples 16-17, wherein the vehicle is an aerial vehicle.

Example 20 includes the method of any of Examples 16-17, wherein the vehicle is a water vehicle.