The field of underwater forensic investigations has witnessed significant advancements in robotic manipulator technologies, driven by the growing need for precise and efficient recovery of submerged human remains and evidence. This comprehensive review examines the latest innovations in robotic manipulator designs specifically tailored for underwater forensic applications, with a focus on mechanical configurations, actuation systems, material resilience, and control mechanisms. The paper begins by analyzing the critical role of degrees of freedom (DoF) in manipulator dexterity, comparing 4DoF and 6DoF systems, and addressing the challenges posed by buoyancy and water resistance. It further explores gripper mechanisms, emphasizing the advantages of soft robotics and hybrid designs in minimizing damage to fragile remains. The review provides a detailed comparison of actuation technologies, including hydraulic, electric, and emerging systems like shape memory alloys (SMAs) and magnetic actuators, highlighting their respective strengths and limitations in underwater environments. Material selection is discussed with a focus on titanium alloys for their high strength-to-weight ratio and corrosion resistance, as well as polymer coatings to mitigate biofouling and enhance buoyancy. Control systems are evaluated for their ability to integrate haptic feedback and autonomous grasping algorithms, ensuring precise and adaptive manipulation of delicate evidence. Challenges such as limited battery life in deep-sea operations, water resistance, and corrosion are critically examined, alongside proposed solutions like hybrid actuation systems and swarm robotics for large-area searches. The paper also outlines future trends, including AI-assisted grasping, hybrid locomotion systems, and advancements in material science to improve durability and performance. By synthesizing these developments, this review aims to guide researchers and forensic teams in selecting optimal manipulator designs, ultimately enhancing the efficiency and safety of underwater forensic operations. Strategic investments in these technologies are recommended to address current limitations and unlock new capabilities in this critical field.
Allen et al. (Wed,) studied this question.