Harnessing robotics for exploration and the discovery of new species

Introduction

Exploration has always been an inherent human instinct, driving us to venture into uncharted territories and uncover the mysteries of our planet. In recent years, the field of robotics has played a transformative role in pushing the boundaries of exploration, particularly in discovering new species. By integrating advanced robotic technologies and scientific expertise, researchers have accessed remote and inhospitable environments with unprecedented precision and efficiency.

How do they work, and what is their purpose?

Robotic fish work by emulating the locomotion and behaviour of real fish to navigate and interact with the underwater environment. They incorporate various mechanisms and technologies for propulsion, manoeuvrability, sensing, and control. Here’s a breakdown of how they work and their purpose:

1. Locomotion: Robotic fish use different propulsion methods to move through the water. These methods typically mimic the movements of real fish, such as undulating their bodies or flapping their fins. By oscillating or flexing their fins, they generate forward thrust and propulsion. This biomimetic approach enables them to achieve agile and efficient swimming, similar to their biological counterparts.
2. Actuation Systems: Robotic fish employ various actuation systems to generate the necessary motion for swimming. This can involve electric motors, artificial muscles, or hydraulic or pneumatic systems. Electric motors drive the fins or propellers, while artificial muscles replicate the contraction and expansion of real fish muscles. Hydraulic or pneumatic systems use fluid or air pressure to actuate the fins or other propulsive mechanisms.
3. Sensing and Control: Robotic fish incorporate sensors and control systems to navigate and interact with their surroundings. Depth or pressure sensors help them maintain the desired swimming depth and adjust buoyancy. Vision systems like cameras capture visual information for obstacle avoidance and object detection. Navigation systems, including IMUs or GPS, determine the robot’s position and orientation underwater. Communication systems allow real-time monitoring and control from a remote operator or central control station.
4. Applications and Purpose: The primary purpose of robotic fish is to perform tasks in underwater environments that are challenging or impractical for humans. Some key applications include:

• Underwater Exploration: Robotic fish are used in scientific research and exploration to study marine ecosystems, collect data on aquatic species, and investigate underwater phenomena. They can access difficult-to-reach areas and gather information that aids in understanding marine life and habitats.
• Environmental Monitoring: Robotic fish play a role in monitoring water quality, detecting pollution, and collecting data on marine environments. They can navigate through water bodies, collecting samples and monitoring changes in the ecosystem. This information helps in environmental conservation efforts and understanding the impact of human activities on aquatic environments.
• Underwater Surveillance: Robotic fish are deployed for underwater surveillance and security purposes. They can patrol sensitive areas such as ports, dams, or oil rigs, providing enhanced surveillance capabilities and detecting potential threats.
• Education and Outreach: Robotic fish serve as educational tools to engage students and the public in marine biology, robotics, and engineering topics. They offer a hands-on and interactive learning experience, promoting awareness and understanding of underwater ecosystems and technological advancements.

Design and development

The design and development of robotic fish involve several stages, including conceptualization, prototyping, testing, and refinement. Here is an overview of the design and development process:

1. Conceptualization: The process begins with the conceptualization of the robotic fish. Engineers and researchers study the locomotion and behaviour of real fish, analyse their anatomy, and understand the principles of hydrodynamics. They identify the fish species to mimic and define the desired characteristics and performance goals of the robotic fish.
2. Design Specifications: Based on the conceptualization, design specifications are established. These specifications include the robotic fish’s size, shape, weight, swimming capabilities, power requirements, and other functional requirements. The design specifications serve as a guide throughout the development process.
3. Mechanical Design: The mechanical design phase involves creating the physical structure of the robotic fish. CAD (computer-aided design) software is used to design the body, fins, joints, and other mechanical components. The design considers factors such as hydrodynamics, buoyancy, materials, and manufacturing techniques.
4. Actuation and Control System: The actuation and control system design focuses on selecting and integrating the appropriate mechanisms to achieve the desired swimming motion. This includes the selection of actuation methods such as electric motors, artificial muscles, or hydraulic systems. Control algorithms are developed to regulate the movement and coordination of the fins or body segments.
5. Sensor Integration: Sensors play a crucial role in providing feedback and enabling the robotic fish to perceive its environment. The selection and integration of sensors depend on the specific application requirements. Depth sensors, pressure sensors, accelerometers, gyroscopes, and vision systems are commonly used to gather data for navigation, obstacle avoidance, and environmental monitoring.
6. Power and Energy Systems: The power and energy systems are designed to provide the required energy for the operation of the robotic fish. The choice of power source depends on factors such as size, endurance, and power demands. This can include rechargeable batteries, solar panels for energy harvesting, or even wireless power transfer techniques.
7. Prototype Development: Once the design is finalised, a prototype of the robotic fish is built. Prototyping involves fabricating the mechanical components, integrating the actuation and control systems, and incorporating the sensors. Rapid prototyping techniques such as 3D printing or CNC machining are commonly used for quick iteration and testing.
8. Testing and refinement: The prototype is tested in controlled environments such as tanks or pools to evaluate its swimming performance, manoeuvrability, and functionality. Tests may include assessing speed, agility, stability, endurance, and response to control commands. Based on the test results, adjustments and refinements are made to improve performance and address any issues or limitations.
9. Iterative Development: The design and development process may go through several iterations, with each iteration incorporating feedback from testing and refining the design. This iterative approach helps enhance the robotic fish’s performance, efficiency, and reliability.
10. Scaling and Production: Once the design is optimised, the robotic fish can be scaled up for larger production. This involves manufacturing multiple units using appropriate manufacturing techniques and processes. Quality control measures are implemented to ensure consistency and reliability across the production units.

Mechanisms of robotic fish

The mechanism of robotic fish involves several key components and mechanisms working together to achieve locomotion and control underwater. Here is a detailed breakdown of the main elements and their functions:

1. Body Design and Materials: The body of a robotic fish is designed to resemble the shape and hydrodynamics of real fish. It is typically streamlined to minimise drag and enhance manoeuvrability. The materials used for the body’s construction are lightweight, durable, and often flexible to mimic the natural movements of fish.
2. Actuation Mechanisms: Robotic fish employ various actuation mechanisms to generate motion and propulsion. These mechanisms can be categorised into different types:
3. Oscillatory Actuation: Many robotic fish use oscillatory movements to propel themselves forward. This is achieved by employing flexible or rigid fins that oscillate back and forth, generating thrust similar to the movements of real fish fins. The actuation of the fins can be achieved through the use of electric motors, hydraulic or pneumatic systems, or artificial muscles.
4. Undulatory Actuation: Some robotic fish employ undulating motions to propel themselves. This involves creating a wave-like motion along the body, which propels the fish forward. The undulating motion can be achieved through the use of segmented body sections or flexible materials that contract and expand.
5. Fin Design and Control: The design of robotic fish fins is crucial for achieving efficient propulsion and manoeuvrability. The fins are often flexible and can be adjusted in shape, curvature, or stiffness. The control of the fins’ movements is achieved through sophisticated control algorithms that regulate the actuation mechanisms. These algorithms can mimic the neural control found in real fish, enabling precise control over the fins’ motion.
6. Sensing and Feedback: Robotic fish incorporate sensors to gather information about their environment and their own movements. These sensors may include depth sensors, pressure sensors, accelerometers, gyroscopes, or vision systems. The collected data is processed and fed back into the control system, allowing the robot to adjust its movements based on real-time feedback.
7. Control Systems: The control system of a robotic fish is responsible for coordinating the various components and ensuring efficient and stable locomotion. It incorporates algorithms for motion control, navigation, and stability. The control system takes input from the sensors, analyses the data, and generates commands for the actuation mechanisms to achieve the desired motion and behaviour.
8. Power and Energy Systems: Robotic fish require power sources to operate. The power systems can include rechargeable batteries, onboard power generation through solar panels, or energy harvesting mechanisms. These power sources provide the necessary energy to drive the actuation mechanisms, sensors, and control systems.
9. Communication and Control Interfaces: Robotic fish can be controlled remotely or operate autonomously. In remote-controlled systems, communication interfaces such as radio frequency (RF) or acoustic communication enable the transmission of control signals to the robot. Autonomous robotic fish may incorporate pre-programmed behaviours or use advanced algorithms to make decisions based on the collected sensor data.

The integration of these mechanisms and components allows robotic fish to achieve biomimetic swimming and manoeuvring capabilities underwater. The combination of accurate actuation, flexible fin design, precise control, and sensing enables these robots to mimic the locomotion of real fish, navigate complex environments, and perform tasks such as exploration, monitoring, or surveillance in underwater settings.

Analysis of Controlling Robotic Fish

Controlling robotic fish involves a combination of sophisticated algorithms, sensors, and control systems. The analysis of controlling robotic fish can be categorised into two main aspects: locomotion control and behavioural control.

1. Locomotion Control: Locomotion control focuses on regulating the movements of the robotic fish’s fins or body segments to achieve desired swimming patterns and motions. This control ensures efficient propulsion, manoeuvrability, and stability. Key elements of locomotion control include:
   • Actuation Control: The actuation mechanisms, such as electric motors or artificial muscles, are controlled to generate the required motions of the fins or body segments. Control algorithms regulate the actuation, controlling parameters such as speed, amplitude, frequency, and phase.
   • Kinematics and Kinetics: The kinematics of the robotic fish’s motion, including its position, orientation, and velocity, are analysed and controlled using mathematical models. Kinetics considerations involve studying the forces and torques acting on the fish and optimising the control to minimise energy consumption and maximise efficiency.
   • Gait Control: Gait control refers to the coordination of the movements of different fins or body segments to achieve specific swimming patterns. Control algorithms determine the timing and coordination of the fin movements, enabling different swimming styles such as steady forward swimming, turning, or acceleration.
2. Behavioural Control: Behavioural control focuses on the higher-level decision-making processes and responses of the robotic fish to its environment. It involves analysing sensor data, processing information, and making decisions based on predefined behaviours or autonomous learning. Key elements of behavioural control include:
   • Sensor Integration: Robotic fish incorporate various sensors, such as depth sensors, pressure sensors, accelerometers, gyroscopes, and vision systems, to gather data about the environment. Sensor data is processed and analysed to provide feedback for control decisions.
   • Navigation and Obstacle Avoidance: Navigation algorithms are used to determine the fish’s position, orientation, and heading in the water. These algorithms use sensor data, such as depth information and vision inputs, to navigate the fish through the environment and avoid obstacles.
   • Decision-Making and Learning: Advanced control algorithms, such as artificial intelligence and machine learning techniques, can be employed to enable the fish to learn and adapt to different situations. These algorithms can enable the fish to recognise patterns, adjust its behaviour based on feedback, and optimise its movements over time.

Actuation and Propulsion

Robotic fish employ various actuation mechanisms to generate forward propulsion and control their movements underwater. Some common actuation methods include:

1. Electric Motors: Electric motors, such as brushed or brushless DC motors, are commonly used to drive the fins or propellers of robotic fish. These motors can be controlled to produce oscillatory or undulatory movements, allowing the fish to swim and manoeuvre effectively.
2. Artificial Muscles: Some robotic fish incorporate artificial muscles, also known as electroactive polymers (EAPs), which can deform and contract upon the application of an electric field. These artificial muscles can replicate the natural flexing and contracting motion of real fish muscles, enabling more biomimetic swimming movements.
3. Hydraulic or pneumatic systems: In certain cases, hydraulic or pneumatic systems are employed to generate the necessary force and motion for robotic fish. These systems use pressurised fluid or air to actuate the fins or other propulsive mechanisms.

Sensing and Control

Robotic fish are equipped with a range of sensors and control systems to navigate and interact with the underwater environment. These include:

1. Depth and Pressure Sensors: Robotic fish often incorporate depth sensors or pressure sensors to measure the depth of water or the pressure exerted on the robot. This information helps in maintaining the desired swimming depth and adjusting buoyancy if necessary.
2. Vision Systems: Cameras or other optical sensors are integrated into robotic fish to capture visual information about the underwater environment. These vision systems may be used for obstacle avoidance, object detection, or data collection purposes.
3. Navigation Systems: Robotic fish may utilise inertial measurement units (IMUs) or GPS systems to determine their position, orientation, and heading underwater. This enables them to navigate autonomously or follow pre-programmed paths.
4. Communication Systems: Some robotic fish incorporate communication systems to transmit data or receive commands from a remote operator or a central control station. This allows for real-time monitoring, control, and coordination of multiple robotic fish in a swarm or team.

How are robotic fish powered?

Depending on the specific design and application, robotic fish use various energy sources. Here are some common methods of powering robotic fish:

1. Rechargeable Batteries: Many robotic fish utilise rechargeable batteries as their primary power source. These batteries can be easily recharged between missions or operations. The choice of battery capacity depends on the desired runtime and power requirements of the fish.
2. Solar Panels: Some robotic fish incorporate solar panels for energy harvesting. Solar panels can capture energy from sunlight and convert it into electrical power. These panels can be integrated into the body or fins of the fish, allowing them to recharge their batteries while operating in well-lit environments.
3. Wireless Power Transfer: In certain cases, robotic fish can be powered through wireless power transfer methods. This involves transmitting power wirelessly to the fish using electromagnetic induction or resonant coupling. The power can be transferred from an external power source or a charging dock placed in the water.
4. Energy Harvesting: Robotic fish can also employ energy harvesting techniques to generate power from the surrounding environment. For example, they may harvest energy from water currents, vibrations, or thermal gradients. Energy harvesting systems, such as piezoelectric materials or thermoelectric generators, can convert these energy sources into electrical power.

The choice of power source depends on factors such as the desired runtime, the power consumption of the fish, and the availability of charging or replenishing opportunities. The power systems are designed to be efficient, lightweight, and optimised for the specific requirements of the robotic fish. Advances in battery technology, energy harvesting, and power management systems contribute to the development of more autonomous and long-lasting robotic fish.

Conclusion

Robotic exploration has revolutionised the process of species discovery, enabling researchers to access unexplored habitats and delve into the depths of our planet’s ecosystems. The integration of advanced robotic technologies, combined with scientific expertise, has propelled our understanding of biodiversity and facilitated the discovery of new species. As robotics continues to advance, it holds the promise of uncovering even more hidden treasures and providing invaluable insights into the complexity and diversity of life on Earth. By embracing the opportunities offered by robotic exploration, we can embark on a thrilling journey of discovery, expanding our knowledge and appreciation of the natural world.