Robot-assisted gastrointestinal endoscopic surgery (GES) as a kind of natural orifice transluminal endoscopic surgery (NOTES) is the next-generation minimally invasive surgery (MIS). Besides, rendering certain autonomy to a Gas-trointestinal Endoscopic Surgical Robot (GESR) is promising but highly challenging. Therefore, to accelerate the development and augment the autonomy of GESR, we use CoppeliaSim to develop the first robotic simulator for the GESR system (GESRsim) based on our previous design. The GESRsim provides several 3D models and kinematics of our designed manipulators and endoscopic snake bone. Additionally, we build several scenes for robotic GES training and then utilize different programming interfaces to perform teleoperation. Furthermore, several advanced control algorithms, including visual servoing (VS) and deep reinforcement learning (DRL), are implemented to verify the performance of the GESRsim.

Brain needle intervention is a specific diagnosis and therapy procedure in brain disorders, such as brain tumors and Parkinson’s disease. Preoperative needle path planning is a vital step to guarantee the patient’s safety and reduce lesions. For positioning accuracy in the CT/MRI environment, we have developed a novel needle intervention robot in our previous work. Because the robot is currently designed for the rigid needle, the task of preoperative path-planning is to search for an optimal Remote Center of Motion (RCM) for needle insertion. Therefore, this work proposes an RCM recommendation system using deep reinforcement learning. Considering the robot kinematics, this system takes the following criteria/constraints into consideration: clinical obstacle (blood vessels, tissues) avoidance (COA), mechanically inverse kinematics (MIK) and mechanically less motion (MLM) for the robot. We design a reward function to combine the above three criteria based on their corresponding importance level and utilize proximal policy optimization (PPO) as the main agent of reinforcement learning (RL). RL methods are proved to be competent in searching the RCM, which satisfies the above criteria simultaneously. On the one hand, the results present that RL agents obtain the success rate of finishing the designed task at 93%, which has reached the human level in the tests. On the other hand, the RL agents have the remarkable capability of combining more complex criteria/constraints in future work.

This paper presents a modular and reconfigurable mini-robotic system with 5 degrees of freedom (DoFs) towards minimally invasive surgery (MIS). The mini-robotic system consists of two modules, a 2-DoFs rotational end-effector, and a 3-DoFs positioning platform. The 2-DoFs rotational end-effector is based on a spring-spherical joint mechanism, whose rotation is controlled by Bowden-cable. The 3-DoFs positioning platform is based on the linear Delta parallel mechanism. Magnetic spherical joints are adopted to replace the traditional spherical joint. The magnetic joint connections enable fast assembling and disassemble of the end platform and kinematic chains. Different surgical instruments can be installed without changing the driver and control system. A flexible shaft actuates the 3-DoFs positioning platform to arrange the motors away from the manipulator side. Based on these structure characteristics, the 3-DoFs positioning platform’s size is dramatically reduced. The outer diameter of the current prototype is 32.5 mm. The single-axis positioning accuracy of the 3-DoFs positioning platform is within -1 mm to 0.85 mm. Three axes tracking experiments are also carried out, with the positioning errors of ± 1.2 mm for cylindrical curves and -1.5 mm to 2 mm for spherical helix curves. Static and dynamic load capabilities are also tested. Finally, the feasibility of the proposed system is demonstrated.

Robot-assisted single port access surgery (SPAS) brings significant benefits to the patients. However, it is challenging due to the limited incision size and requirements in precision, load capacity, and dexterity. To address these challenges, this paper presents a multichannel SPAS robotic system consisting of two channels of 5-degree-of-freedom (DOF) flexible manipulators and an endoscope channel. Each channel of the manipulators is designed based on a 3-DOF parallel mechanism with three sets of super-elastic Ni-Ti rods and universal joints. This design optimizes the structure for flexibility and safety considerations with a simplified structure compared with conventional parallel mechanisms. Flexible shafts are used for torque transmission from the actuation unit, allowing the motors to be farther away from the patient-side robotic system. The kinematics of the manipulator is derived, and then the reachable workspace and dexterity are analyzed. Furthermore, a prototype of the proposed robotic system is presented and evaluated through adequate experiments. The flexibility of the manipulator is verified via stiffness characterization test. The results of the accuracy tests confirmed that the robotic system can implement manipulation arm with acceptable accuracy. The feasibility and effectiveness of applying the robotic system to the practical operation are also demonstrated through experimentations.

In recent years, piezo-actuated micro/nano positioning stages emerge as a significant tool in the nanotechnology. However, the shortcomings of small positioning stroke and hysteresis of piezoelectric actuators have constrained their further development and applications. In this paper, a novel piezo-actuated hydraulic displacement amplifier (PHDA) based on Pascal's law and area differential principle is first proposed aiming to solve the contradictions among positioning stroke, positioning resolution and mechanism dimension in piezo-actuated micro/nano positioning stages. After a series of optimal designs, the proposed PHDA mechanism is fabricated and experimentally tested. In this study, a piezoelectric (PZT) actuator P-840.20 with open-loop travel of 30 μm is employed, the experimental results indicate that the displacement amplification ratio can reach up to 34.6, thus the maximum output displacement can achieve up to around 1.02 mm. Both theoretical derivation and prototype test results testify the well performance of the proposed mechanism. This new amplifier can be widely extended to practical precision manipulation applications in case of large motion range required.

In recent years, robotic bio-manipulation emerges as a hot research topic in the micro/nano technology. In these applications, biological cell microinjection is a focus since it is a critical process for the further biological research such as genetic engineering and pharmacology research. This study aims to develop a novel robotic biomanipulation system combining with the micro-fluidic chip technology to improve the cell manipulation stability and throughput. Two novel flexure-based large-workspace micromanipulators with modified differential lever displacement amplifier (MDLDA) are presented in this paper. After a series of optimal designs and mechanism modeling, the mechanism performances are evaluated by the FEA method. Finally, the proposed micromanipulators are fabricated and visual-servo controlled to perform the practical zebrafish embryos injection task. In this work, two piezoelectric (PZT) actuators P-216.80 (open-loop travel is 120 μm) and one PZT actuator P-840.20 (open-loop travel is 30 μm) are utilized in the compliant mechanisms, the experiment results indicate that the displacement amplification ratios can reach up to 30.6 and 17.6, thus the maximum output displacements can achieve around 3.1273 mm and 0.528 mm, the rotation angle of the left micromanipulator can reach to around 26.5°. Both theoretical derivation and experimental implementation results well verify the advanced performance of the developed system.