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The steam generator is an important heat transfer equipment in nuclear power plant. Its main component is the tube sheet with thousands of U-shaped heat transfer tubes. The inspection robot repairs the heat transfer tubes by positioning various types of tools to the specific heat transfer pipe, greatly reducing human intervention in the nuclear environment. Based on a brief overview of the research status of inspection robots used in steam generators, the mechanical structure of the body, tube-holding mechanism, collision detection, and trajectory planning are analyzed, problems and challenges are summarized, and the future development trend is prospected.

The reliability of the Steam Generator is a key factor affecting the overall efficiency and safety of nuclear power plant reactors. Under the influence of nuclear radiation, remote control robots are currently used for Steam Generator heat transfer tubes inspection. In this paper, a new inspection robot is designed with better structure and higher working efficiency. Structural modeling and kinematic analysis are carried out. A modular control system is designed and applied for system integration. To verify the practicality of the robot, tube sheet motion experiments and performance analysis are undertaken. It results that the proposed inspection robot efficiently moves on the tube sheet and has excellent motion performance.

A variable magnification ratio transmission structure powered by the electric actuators is proposed to improve the flexibility and portability of the exoskeleton under heavy load carrying condition. The parameters of connecting rod size and hanging position are optimized to ensure that the output torque of active joints can fully envelope the demand load area. The control strategy based on intrinsic sensing is designed to realize the automatic human motion intention prediction and flexible trajectory tracking. The newly developed split embedded connecting rod can accurately measure the human-robot interaction (HRI) force applied to the exoskeleton and extract the human motion intention without being affected by the differences in wearing status. The force tracking control based on the zero-force following is modified by feedforward compensation with extreme learning machine (ELM), which enhances the response speed to human motion intention and reduces the HRI force by 70.6%. Based on multi-sensor information, stacked autoencoder deep neural networks (DNNs) are utilized to realize the automatic locomotion transition and the corresponding control parameters' switching. After optimization by a hybrid algorithm of genetic algorithm and particle swarm optimization (GA_PSO), the identification accuracy is enhanced from 96.2% to 99.7%. The adaptive neural-fuzzy inference system (ANFIS) is used to analyze the plantar pressure to achieve flexible switching between the swing phase and the stance phase. The experiments under various gait motion trajectories assisted by novel weight-bearing exoskeleton are carried out for evaluation, and the performance of the proposed control strategy based on motion intention prediction, locomotion mode identification, and gait phase switching is effectively verified.

The marine environment is complex and dangerous, underwater robots instead of humans to explore the ocean have become an inevitable trend of future technological development. Frogs are explosive and flexible when they swim, these advantages provide important ideas for designing underwater robots. Based on the previous research results of our team, a new generation of frog inspired robot is designed in this paper. While optimizing structural performance, we add two degrees of freedom to the hip joint. The motion space of the hind limb is obtained through kinematics analysis, combining the observation data of wild frogs, the three-dimensional trajectory of the frog-inspired robot in each motion phase is fitted, and the acceleration planning is focused on the propulsion phase. Finally, the rationality of the trajectory planning and the reliability of the structure are verified through experiments.

To ensure applications requirements of rocket storage tank precision polishing, a 6-dof parallel collision detection mechanisms mounted on the end of rocket tank polishing robot used for heavy load condition is designed in this paper. Its each branch chain consists of spherical joint, revolute joint and prismatic joint, in which the prismatic joint is driven by the cylinder. The collision detection principle is to judge whether an external collision occurs by real-time detecting the changes of cylinder pressure and cylinder displacement. Besides, the kinematics of parallel mechanisms is analyzed and a numerical iteration algorithm for forward kinematics based-on our previous work is proposed here. The proposed algorithm can be not only used for 6-dof parallel mechanism but also for more or less than 6-dof ones in which Jacobian matrix is not square. Moreover, it is not sensitive to the iteration initial value. Then, a linear trajectory is simulated to verify the effectiveness of the proposed algorithm. Finally, the simulation results prove the accuracy of the proposed algorithm.

This paper presents a light-weight lower extremity exoskeleton and its associated control method to augment the locomotion for climbing stairs. A compact slider crank mechanism is designed for the knee joint to offer the required torque. A spring based quasi-passive hip joint is adopted to compensate gravity force of lifting leg. A hybrid assistive control strategy is proposed to ensure the requirement and coordination of different gait phases for the exoskeleton. In standing phase, a direct gravity balancing method is used to support the body and payload. In swing phase, a force tracking control method is utilized to enhance leg mobility. Stair climbing tests show that the gravity compensation method and force-tracking controller enhance the stair climbing mobility, and demonstrate the feasibility of the designed exoskeleton and the proposed hybrid control strategy.

Study on frog swimming mechanism is an interesting topic, and a frog inspired robot has been designed with the pneumatic muscles as the driver. To improve the design and trajectory planning, the optimization of the robot was studied in this paper. For the robot structure, the limb size was optimized in ADAMS and joint parameters of the bionic robot are optimized by particle swarm optimization (PSO) method. Meanwhile, the trajectory during propulsive phase is also optimized in Matlab. Simulations in ADAMS verified the feasibility of the proposed optimization for the frog inspired robot.

Most of the upper limb exoskeletons proposed in the literature are designed for rehabilitation, however, there are few developments for activities assistance of daily living. This paper presents a wearable upper limb exoskeleton for activities assistance of daily living with the feature of mobility. It provides five degrees-of-freedom (DOF) for each arm, where 3 DOF and 2 DOF are given to the shoulder and elbow, respectively. And it allows the wearer to keep freedom and mobility as usual after wearing the device. To conquer the strength-to-weight limitations of exoskeleton mobility, we introduced gravity balance method to reduce energy consumption and proposed a novel cable-driven joint mechanism to reduce its total weight to 4.2 kg. In order to verify the plausibility of joints design and its performance on motion assistance, joints tracking test and motion assistance test were carried out, respectively. Their results support that the proposed exoskeleton is feasible and efficacious.

We propose an indirect stiffness estimation method of flexible joint based on system function approximation in this paper. At first, an alternative system function is constructed. Then a system function estimation method based on saturation function is introduced to estimate its output. Taking the estimated system function as prior model, the least square method is finally introduced to identify the joint stiffness. Meanwhile, another system estimation method based on RBF neural network is also introduced to verify the efficiency of the former one. There are two advantages of the new proposed stiffness estimation method. Firstly, it is more robust to environmental noise, since no basic version or filter version of angle acceleration is maintained in the estimation process. Secondly, it's easy to apply because only measurements of joint angle on motor side, joint velocity on motor side and joint angle on link side is needed.

This paper presents a jumping four-bar mechanism using pneumatic muscle actuators. The mechanism has three joints and each one is powered by one artificial muscle; jumping and restoring action is achieved by muscle contracting force and spring respectively. Kinematic analysis is performed in landing and airborne phase respectively. Vertical jumping simulation is performed according to the prototype parameters and results demonstrate the kinematic analysis and show the torques supplied by muscles can meet the jumping requirement.

A frog-inspired hopping leg is designed in this paper, and the pneumatic muscle is utilized as the driver. The muscles are bioarticular muscles which can not only increase the range of the joint angle, but also make the robot compliance more similar to real frogs. Kinematics analysis of pneumatic muscles is accomplished, and the experiments of motion simulations based on virtual components are given, as the theoretical basis of further design of the control system.

Comparing with the local algorithm in stereo matching, the global algorithm can get highly quality disparity space image (DSI) usually. The graph cuts algorithm, as the traditional global matching method, can get the highly quality DSI with long computation time, so the graph cuts algorithm is difficult to used in real-time matching applications. In this paper, a new method is proposed to accelerate the matching speed. Firstly, the segments of the image are calculated using the Gaussians pyramid (DoGs) computing method, secondly calculate the disparity range of two corresponding image segments in image pair using the color feature, and every segment pair is matched based on graph cuts algorithm according to the offset of disparity range in parallel time, finally all the segments are assembled into a whole disparity image. The experimental results show that the matching speed is accelerated greatly with a high disparity image quality.

A new type of integration robot of arm and leg has been developed. Its cross gait of walking quickly on the barrier-free road was designed and planned. Gait optimization algorithm based on the energetic optimum was put forward, which can optimize the robot cross gait, and get the corresponding optimization parameters of walking gait. The simulation results show that the robot has the very good exercise continuity and stability on the basis of low energy consumption when it adopts the optimized cross gait.

A new type of reconfigurable modular robot is developed. This robot has some characteristics: realize modularization in the structure, the electrical, the drive, the kinematics and dynamic performance; It can construct the work topology rapidly according to the actual need and complete tasks in real time. The control method of reconfigurable modular robot is researched according to these characteristics. Taking the single module as the Agent model, the intelligent control system of the robot is established, and the control algorithm of the robot is researched emphatically to prove its astringency . Finally the analyses of the simulation experiment are made.

Walking robots with operating capability represent the main direction of future robots development. The limb mechanism, which integrates legged locomotion and arm manipulation, is proposed as a novel design to overcome the operation problems of walking robots. This paper describes the design concepts, analyses and summarizes present development of robots with limb mechanism, and points out some key problems that have to be solved for the robot design.