Our Newest Innovation
The most advanced ROV to come out of Jesuit Robotics ever, Lazarus is a multifunctional ROV that utilizes SMART tools, our new ip camera system, custom made electronics, and new software to accomplish a variety of tasks with ease. With over a hundred hours of component level unit testing Lazarus is designed to operate without downtime, significantly decreasing costs and increasing operational efficiency. Designed for use in the Port of Long Beach, we understand that only one hour of downtime costs the port twenty million a hour.
Rovotics’ design process begins with ideas discussed and developed on the whiteboard, then turned into physical prototypes. Detailed CAD files based on these prototypes are then turned into work-orders for manual manufacturing or the CNC mill. This year, we created Lazarus’ modular core structure in parallel with the tools, which allowed for a more rapid production time and the ability to test earlier in the development cycle.
Lazarus consists of two polycarbonate decks connected by struts angled at 45 degrees for interframe rigidity. Using polycarbonate versus aluminum allows for rapid prototyping and the manufacturing of oversized parts using common shop tools. Polycarbonate is also less dense than aluminum and corrosion-resistant, making Lazarus ideal for use in the harsh ocean environment.
The top deck holds six thrusters and two cradles that hold the electronics housing, while the bottom deck holds payload tools and a video junction box. The electronics housing and top deck are easily separable from the bottom deck via four screws and a SubConn connector. The housing is waterproofed with O-ring seals in our custom flange-and-faceplate design, and is pressure tested to 5 meters using a vacuum pump. Placing SubConn connectors on the perimeters of the flanges creates room for compact navigation cameras integrated into the electronics housing.
The housing is also the major buoyancy component of the ROV. By integrating buoyancy and ballast directly into Lazarus’ modular structure, there is no need for additional buoyancy material. During the design and manufacturing process, we tracked wet and dry weights for each component, and the water displacement of each hollow assembly. We used this information to fine tune the ROV and achieve a balance between neutral buoyancy and a dry weight of 17 kg.
Our new Tether Control Unit, or TCU, is the communications and power hub between the ROV and control computers. To comply with MATE safety requirements, all Anderson power connectors are now crimped and have strain reliefs attached, and the TCU only uses DC power. The TCU also includes status lights, voltage, and current meters, as well as a main emergency power switch that can quickly shut down the ROV.
The TCU is protected from the 48V power supply with an in-line 30A fuse and a 30A circuit breaker. It houses networking systems to provide TCP/IP based communication to all connected devices, as well as two pneumatic valves to control specialized tools. This year, we also added a programmable display, ideal for customization based on user needs.
Our custom tether contains stranded silicone power wires, a CAT6A Ethernet cable, a coaxial video cable, and pneumatic lines. Custom waterproofed 3D printed capsules encase the connections between those cables and the SubConn connectors, protecting delicate splices and improving durability over previous designs. The highly-visible, red woven polyurethane sheathing has proven to be flexible and abrasion-resistant, resulting in a safe and trouble-free tether. Because of this lightweight and safe design, our tether management protocol only requires two trained individuals to flake out or coil the tether, using an over-hand-under-hand method. Strain relief is provided by a carabiner securely attached to a hard point on the ROV, and the tether includes incompressible buoyancy devices that prevent entanglement with the ROV during operations and serve as navigation aids.
Lazarus’ control system consists of two platforms – topside software running on a Raspberry Pi, and bottomside software running on embedded microcontrollers. Both sides communicate using the UDP protocol, which allows each end to stream data in a connectionless state.
Our completely new topside platform, developed in Node.js with pilot perspective in mind, features modular architecture that increases serviceability, and unique web pages for the pilot, co-pilot, and operations specialist that are accessible from any standard web browser.
To ensure a safe working environment, our clean graphical user interface displays real-time ROV telemetry and operating status. Programmable LED lights on the ROV also provide the deck crew with quick visual indicators of its operating status at all times. In the event of a complication, a simple hotkey press can quickly disable or enable features on the ROV, such as the thrusters.
To expedite development of the new topside software, we built three different unit-testing platforms that allowed us to test basic ROV systems and functions on land and in the water, as well as perfect the vector-thrust configuration before integration with Lazarus. Use of these testing platforms increased overall organizational efficiency by allowing for continuous, parallel development between all Rovotics departments.
To organize tasks and meet project deadlines for deliverables and documentation, the software department was an early adopter of Rovotics’ new Plan, Build, Test, and Release, or PBTR, project management process. This new system facilitated collaboration within and between departments, which helped us request and produce deliverables according to schedule.
Lazarus’ electronics systems were designed with performance, serviceability, and safety as priorities. Two compact 48 to 12 volt DC-DC converters with built-in protection features ensure safe and reliable power delivery to all thrusters, tools, and logic systems.
Continuing our multi-year electronics design evolution, all microprocessing controller boards were designed and assembled by Rovotics. Each custom microcontroller contains all components necessary for its specialized function, eliminating the need for more costly and bulky stacked Arduino shields. The main microcontroller board handles critical functions such as thrusters, camera switching, communication with daughter boards, and ethernet communication to topside. Subcritical functions are divided between three modular expansion cards, minimizing thruster, tool, and sensor response times. The modular expansion card system cuts down on troubleshooting and repair time, as circuit boards can be replaced easily and inexpensively. To enable a flexible camera system with improved pilot perspective two pilot and six task cameras are controlled using a custom video switching board.
The electronics connect to the subframe and tether using a combination of wet-mateable SubConn and permanent Blue Robotics connectors, which have both proven reliable on our previous designs. Blue Robotics connectors are also reasonably priced, making them an ideal choice for purchase over in-house manufacturing wherever a permanent connection is needed.
Lazarus is equipped with six thrusters in a vector configuration, giving the pilot omni-directional control. Four thrusters are mounted at 45 degree angles on the corners of the top deck, with two on the mid-plane for verticals. This allows for unobstructed water flow and gives the pilot very responsive controls during operations.
Rovotics began using Blue Robotics T-100 thrusters last year because their size and weight helped us meet restrictions set by the RFP. We originally planned to reuse the same thrusters on this year’s ROV, but we ultimately ordered all new T-100s for Lazarus because we recognized the importance of a design and manufacturing change Blue Robotics made on the latest version. Rovotics has manufactured its own thrusters in the past, but understanding the complexity of this process, we found that buying Blue Robotics thrusters was a far more cost and time effective solution than building our own. This decision allowed us to apply our resources to other project areas.
Pilot perspective and Specialized Mission Assist ROV Tool Technology, or SMART-Tech, guided our design process for all tools. We designed our camera system to enable the pilot to see both the mission tool and objective simultaneously, and all tools were designed to help the pilot easily engage with each objective in seconds.
Lazarus’s custom multifunctional gripper was designed to quickly and efficiently complete a variety of tasks. A pneumatic piston opens and closes the gripper’s jaw, and SMART-Tech custom cutouts adapt to different objects and hold them securely in place. A magnet on the jaw makes pulling the platform pin simple, and a dedicated camera gives the pilot a wide-angle view of the objective while keeping the tool in sight.
Our innovative valve-turner uses a three-pronged appendage to rotate the faucet. A SMART-Tech alignment cone and strategically placed camera help the pilot easily guide the tool onto the faucet, and the faceted design keeps it engaged even if the ROV shifts position. During underwater trials, we discovered that the cone can also be used to efficiently push the fountain locking mechanism open and closed. Our new, bayonet-sealed motor housing was reverse-engineered from the shaft seal design used on SeaBotix thrusters, and is one-third the size of our previous designs. The motor is available in a variety of RPM’s and torques, making the entire assembly adaptable to a wide range of applications.
Lazarus’ core sampler is placed near the ROV’s center of mass to allow for more precise alignment and maximum downward force, resulting in larger and more secure samples. The central location and overall design is the result of three years of development and testing after recognizing ways of improving upon past designs. A dedicated camera and SMART-Tech alignment cone assist the pilot in guiding the ROV into place directly over the middle of the sediment. The thin-wall stainless steel collection tube is oversized to gather samples larger than 150 ml, which are held in place via suction from a one-way check valve. The entire tool is easily detachable from the ROV via a twist mechanism with magnetic lock.
Our harvester is a multifunctional tool designed to efficiently collect objects such as clams and beacons. A bottom shelf with a sloped edge uses hydrodynamic force to push objects into a cage. A swing gate operated by the gripper ensures objects are securely contained after collection.
A cool-white LED RFID activation light, RFID sensor, and red LED simulated raman spectrometer have been combined into a compact array centered at the front of the ROV to optimize pilot perspective. Each light is potted with clear epoxy in an aluminum heat sink to prolong diode life, and the cool-white LED also serves as a general purpose work light. To maintain simplicity and reduce cost, Lazarus features a single perspective camera to accurately align the RFID sensor array as well as the buoy marker.
The buoy marker securely attaches to a container holding high-risk cargo via the use of a magnet and custom carabiner. Once attached, a PVC coated nylon line unspools as the marker floats to the surface to clearly identify the container’s location.
The rebar tool efficiently moves rebar using a magnetic retrieval system and pneumatic release mechanism. A dedicated camera and SMART-Tech cone allow the pilot to quickly engage with the rebar. The tool itself serves as the fourth strut of the ROV, decreasing weight and size without sacrificing rigidity.