With the intelligent development of manufacturing industry, industrial robots are more and more widely used for continuous contact operation, such as polishing, sanding, burring and assembling. End-effector with force control is a critical component of robots used for hybrid force/position control and continuous contact operation, which has an important effect on the operation quality and application field extension. In view of the above situation, it is of great importance for developing new robotic end-effector of high-performance to investigate the state, analyze the characteristics and key technology, and forecast the trends of development. The background of end-effector with force control was introduced firstly, and then the composition & classification, working mode and operation principle was presented. The key technologies of end-effector with force control were refined, including the comprehensive theory and optimization technique of parallel manipulator configuration, design technique of constant force compensatory actuator, technique of compensation of mass force, technique of flexible collision and technique of decoupling control. Furthermore, the mechanical, pneumatic, electrically driven end-effector with force control of single-DOF and multi-DOF was detailed summarized, as well as the advantages and disadvantages. The technology trends of the end-effector with force control include high precision and frequency response, electric driving, multi-DOF flexibility, high load capacity, integration and intellectualization. Analysis shows that the mechanical or pneumatic end-effector with force control is widely used nowadays, which has the disadvantages of large lagging, low control precision and response and can only realize constant force control of single-DOF. As a result, research on intelligent and electrically driven robotic end-effector with force control of high precision, response and multi-DOF will play an important role for the improvement of force control precision, surface adaptability, quality and efficiency of processing & assembly, and effectively promote the intelligent operation level of industrial robots.

In order to quickly and accurately determine the fault classification of CNC (computerized numerical control) machine tools, a fault classification decision method based on the meta-action unit was proposed, which could avoid costly handing of minor faults while key faults were ignored. Firstly, to refine the granularity of fault analysis of CNC machine tools, which made analysis process more convenient, according to "function-motion-action", the CNC machine tool was decomposed to the meta-action layer by layer from the point of view of system functional decomposition. Secondly, the concept model of the meta-action unit was elaborated by analyzing the decomposition process and three elements of a standard meta-action unit were defined.Thirdly, fault modes of the meta-action unit were analyzed and summarized comprehensively. Fourthly, three levels of fault modes of meta-action unit were defined. According to the evaluation index, the fault modes of CNC machine tools were evaluated, and then the grey clustering theory was applied to analyze the quantified evaluation value of the fault modes, and the original decision table of fault mode classification was established based on the clustering results obtained. After that the knowledge reduction of the original decision table made the decision rules further simplified through the rough set theory, ultimately a fast and accurate fault classification decision method was formed. Finally, the rationality and effectiveness of the proposed method was demonstrated by an example analysis of the rack movement meta-action unit in a certain CNC machine tool. The example analysis result indicated that the fault mode levels of CNC machine tools could be determined quickly and accurately so as to improve decision efficiency by this method, the obtained conclusion was more clear and pertinent, which could provide the basis for the subsequent maintenance process control. The research results can provide useful guidance for relevant enterprises to determine the fault levels of CNC machine tools, and to optimjze the allocation of enterprise maintenance resources to some extent.

Aiming at the poor performance of traditional speed measurement system based on speed detectors such as tachogenerators and optical encoder that not good at low speed operation, real-time capability and anti-interference done by the storm structural asymmetry, electromagnetism and so on, a high-precision and wide-range real-time filter speed measurement method is presented. The mechanical structure characteristics and working principle of the claw pole permanent magnet AC tachogenerators were analyzed in detail. The speed measurement model of the claw pole permanent magnet AC tachogenerators was built under the condition of structural asymmetry. The proposed reduced-order adaptive unscented Kalman filter algorithm was engineering application oriented and based on the interactive dual-mode, which could achieve the real-time measurement for permanent magnet rotors and had the advantage of low computational complexity. The reduced order and full order interactive dual-mode adaptive algorithms were running parallel. While using the reduced-order estimation to ensure the real-time performance of the system, a long time full order algorithm was used to correct the reduced-order estimation and improve the speed measurement accuracy. The simulation results indicate that the proposed speed measurement method not only has the good robustness to structural asymmetry, but also has the excellent performance to track the rotation speed with high precision in real-time under wide-range condition, which has certain engineering guiding significance.

Prestressed concrete cylinder pipe (PCCP) is widely used in water conservancy projects, industrial water supply and so on. In view of the problems of inefficient and difficult to guarantee the quality of PCCP port grinding, a grinding robot for socket and spigot of PCCP is innovatively designed. First of all, according to the requirements of working in-service environment, the structure design and prototype production for the port grinding robot were carried out, and the skidding failure of the robot was analyzed by field test. Secondly, according to the grinding process that the grinding robot overcoming the frictional force to make a circumferential rotation around the pipe port, the pressing force model and reliability model were established on the basis of mechanical analysis. The dynamic reliability of the whole grinding process was analyzed using the stochastic perturbation method. The key part of the grinding robot with the lowest reliability was obtained. Finally, the working parameters affecting the reliability sensitivity of the port grinding robot were analyzed, and it was concluded that the parameter making the port grinding robot towards reliability fastest was from the radius of the driving wheel. The research results lay the foundation for the development of large-scale PCCP automated manufacturing equipment with independent intellectual property rights and the subsequent reliability optimization design.

Aiming at the fracture fault of the joint bolts of support pivots of tumble gate during the trial operation of ship lift in the Three Gorges, the main reason of the failure was analyzed and concluded that the pre-tightening torque 1 233 N·m was too small and the strength of the bolt A2-70-M36 was not enough. The method to improve the reliability of joint bolts of support pivots of lower head tumble gate of ship lift in the Three Gorges was proposed. Firstly, the lifting forces of hydraulic hoist cylinder and the maximum working loads of the joint bolts of support pivots were obtained under four working conditions including the gate closing, opening without water, closing and opening with water. In the working condition with water, different backwater heights of 0.8, 0.7 and 0.5 m were applied when the door was closed, and 0.8, 0.5, 0.3 m when the door was opened. Then, according to the rated output force of hoist, the backwater height was below to 0.7 m and 0.3 m in the actual closing and opening process respectively. Lastly, based on the norm of residual preload, the required pre-tightening torque was subsequently confirmed as 2 400 N·m. Strength calculation results indicated that selecting and using M36 bolt of class 10.9, the joint bolts of support pivots of tumble gate could meet the strength requirements. The operation of the tumble gate after maintenance shows that the calculation method is reasonable and can provide a technical basis for the safe operation of the lower head tumble gate of ship lift in the Three Gorges.

Aiming at the problems that the traditional spatial arc fitting method has poor robustness and low fitting accuracy, a robust spatial arc fitting optimization method is proposed. Firstly, on the basis of Lagrangian multiplier method, the objective function was established based on the constraint of the plane condition, and then the spatial arc fitting equation was derived. Secondly, the error tracking point was eliminated by using the RANSAC (random sample consensus) algorithm, which applied the high stability of RANSAC to the point cloud optimization of spatial arc fitting to improve the fitting accuracy. Finally, the feasibility of the proposed spatial arc fitting optimization method was verified by experimental analysis, and the fitting accuracy of the proposed method was analyzed through comparing with the traditional fitting method. The experimental results showed that the relative accuracy of ordinary arc point cloud fitting was about 0.003, and the relative accuracy of complex arc point cloud fitting was about 0.01. Compared with the traditional fitting method, the proposed method effectively solved the problems of low fitting accuracy and poor robustness. The research results indicate that the proposed spatial arc fitting optimization method can enhance robustness by using Lagrange multiplier method and improve fitting accuracy by using RANSAC algorithm to eliminate the error points, which has a wide range of practical engineering application.

The technology of directional reaming while-drilling for oil and gas wells is mainly used to optimize the well structure, improve the cementing quality and avoid drill pipe sticking caused by wellbore shrinkage. The applicable rock breaking tool for this drilling technology is reaming bit. The research and development of a novel reaming bit was conducted based on the actual demands of directional reaming while-drilling for deep wells in Tahe oilfield. Based on the optimization design of reaming structure, crown profile and cutter distribution, the CK306B PDC (polycrystalline diamond compacts) bit for directional reaming while-drilling was developed. Specifically, the basic reaming structure was designed with two-stage, and the crown profile of the pilot bit was designed as a slight-raised curve and the cutters were distributed on the basis of the self-balancing principle. The simulation analysis of stability and hydraulic characteristics of novel reaming while-drilling PDC bit was carried out. Field application in directional reaming while-drilling for deep wells in Tahe oilfield showed that the bit had a good performance, wherein, the reaming diameter was larger than 170 mm while the build-up rate reached 9.9°/30 m, which indicated that either the reaming ability or the build-up ability of the bit satisfied the engineering requirement. Moreover, the average footage of reaming bit was 93 m and the ROP (rate of penetration) of the bit was 1.24 m/h, which were 50% and 4% higher than foreign congeneric bits used in similar well section, respectively. The research result shows that it is feasible to use the novel PDC bit for directional reaming while-drilling in deep-well because the novel bit can meet both the requirements of well track control and directional reaming. Besides, the lateral imbalanced coefficient of the novel reaming bit can be controlled within 0.05, which will improve the stability of the bit, reduce the bit failure risk and prolong service life of the bit.

As the key parameter, the length of the jaw of the parallel mobile grip determines the size and quality of the grip, and it also determines whether the conductor is damaged. In view of the fact that the length of the jaw was mostly determined by the condutor diameter magnification ratio and the test, and it lacked some theoretical support, the structural characteristics of 1 660 mm² large cross section carbon fiber conductor were analyzed, and the radial compressive strength criterion of carbon fiber was obtained through tests. Referring to the stress simulation results of the 1 250 mm² conductor, the plastic deformation range of the aluminum shaped wires was obtained. The simulation study of 1600 mm² large cross section carbon fiber conductor was carried out when the length of the jaw was 350, 325 and 275 mm. Based on the simulation results, a grip for JLZ2X1/F2A-1660/95-492 type 1660 mm² large cross section carbon fiber conductor was designed and optimized. After optimized design, the length of the jaw was reduced by 21.9%, and the weight of grip was reduced by 25.0%. The research results can provide reference for the design and analysis of the grip.

In order to improve the working efficiency of a lawn mower and reduce its energy loss during long-term operation, the modeling and simulation analysis of the cutterhead and blade in the header is performed, and the energy-saving effect is achieved through the optimization design for the shape of the cutterhead corner area and blade. Firstly, the numerical simulation of the flow field of the cutterhead during mowing process was performed to analyze the pressure conditions of blades and the cutterhead, the speed of blades and the torque conditions of blades; Secondly, according to the law of flow field analysis, the shape of the cutterhead corner area and the blade were optimized, and three optimization schemes were proposed; Thirdly, the torque was used as the main evaluation index of the scheme energy-saving effect, the optimal design scheme was obtained by comparing with the original scheme; Finally, the optimized blade was completed and the test was carried out on a real car. The error between the test result and the simulation result was within 5%, which indicated that the simulation result was effective, and the test result verified the energy-saving effect of the optimized program. Simulation and experimental results show that the cutterhead shape has an important influence on the flow field and torque during the operation of the lawn mower. Shaped blade helps to reduce the eddy current and wind resistance of the flow field, which reduces the blade torque to achieve the purpose of energy saving and efficiency improvement.

Underactuated gripper has good adaptive characteristics and is commonly used in robotics. Due to the multi working modes of underactuated gripper, the parametric optimization is difficult. A multi-mode parametric optimization method was proposed for the typical planar damped underactuated gripper. The investigated gripper has two working modes, which are two-point grasping and enveloped grasping. First, the static analysis of working modes was carried out, establishing the analytical relation between the output grasping force and the input torque, and the external constraint method was introduced to solve the hard problem of determination the static equilibrium position of the enveloped grasping. Further, the grasping force of each working mode was optimized to obtain the optimal structural parameters, and the common characteristics of optimal direction were analyzed. Finally, through the ADAMS simulation, the effectiveness of optimal results for different modes was verified. The results showed that both working modes had the same optimal direction and the effects of optimization were obvious. The research provides a reference for the optimal design of multi-mode underactuated gripper.

The manipulator is one of the most important parts of industrial assembly exoskeleton, which has an important effect on the support and stability of tools, and it determines the performance of the exoskeleton. Considering the current design method of the humanoid manipulator and according to the arm size of Chinese man, a manipulator for industrial assembly exoskeleton was designed based on spring-linkage mechanism. To prove the feasibility of weight-loss performance of this manipulator, the fundamental principles of the manipulator for tools support was explained according to the static balance system of spring-linkage mechanism. Nine groups of simulation experiments were designed with different parameters of initial angle θ₁ and θ₂ to study the bearing performance of this manipulator by a new reverse thinking method presented, so that the relation curves of lift height and lift force were received under different conditions. The concept of effective load-bearing interval was proposed to explain and study the load-bearing performance. The result of simulation experiments showed that smaller initial angle could get larger interval of effective load-bearing, and the initial angle θ₁ had greater influence on the lightweight performance than the initial angle θ₂. Additionally, it could make the tools installed on the manipulator more stable by enlarging the initial angle. So, it can prove that this manipulator is suitable for the industrial assembly exoskeleton, and provide the other researcher some ideas of study and design for this kind of exoskeleton.

The winding force of the wire rope exerting on the ultra-deep mine hoist drum is intricate in the multi-layer winding process. During the long-term operation process of the hoist drum structure, the degradation of materials and structure damage with time will cause fatigue failure of the drum structure. Therefore, it is necessary to carry out the research of fatigue life of the hoist drum structure under the actual working conditions in the multi-layer winding process. On the basis of the theory of plates and shells, the ultra-deep mine hoist drum was regarded as the rotational symmetric shell under uniform pressure. A mathematical model was set up for the force acting on hoist drum structure. Through analyzing load composition of the drum, dynamic models were established for full load lifting and no-load descent of the steel wire rope on the basis of the dynamics principle of hoisting system, and the dynamic load of the drum structure was determined. The stress-time history curves of the drum in the whole working cycle were obtained through the strength analysis of drum structure in the working process. Based on S-N curves with different survival rates and cumulative damage theory, the fatigue life of the drum structure under different load was analyzed. The results indicated that the maximum equivalent stress both occurred in the constant speed stage on the process of full load lifting and no-load descent, and the maximum equivalent stress appeared in the middle part of supporting wheel and supporting ring of inner wall of the drum. The fatigue life of the drum structure at given survival rate was closely related to the workloads. The research provides theoretical support for mechanical analysis and the scientific design of hoist drum under complicated working conditions in the multi-layer winding process.

The micro-nano probe is a key component of precision measuring machines. Its stiffness characteristics directly affect the overall performance of the coordinate measuring machine. Based on the principle of pressure rod instability, a novel micro-nano probe with variable stiffness characteristics was constructed. The piezoelectric device was used to drive the deformation of the flexible mechanism to change the axial force and lateral stiffness of the flexible support beam, and then the overall stiffness of the constrained supporting mechanism was varied. Considering the stiffness characteristics of the micro-nano probe, the structural stability and the decoupling, the variable stiffness probe based on the cross-cantilever beam support was established. The principle of minimum potential energy was used to derive the stiffness model of the constrained supporting mechanism of the micro-nano probe. Based on the above model the required piezoelectric drive force was obtained. The stiffness curve of the probe with respect to the piezoelectric driving force was described by employing the finite element simulation. Comparing stiffness theory calculated values and simulated values, the average relative error of the axial stiffness and lateral stiffness of the constrained supporting mechanism of the micro-nano probe were obtained. The simulation results showed that the established stiffness model had high accuracy. The result of the study laid a preliminary theoretical basis for the variable stiffness control of the novel micro-nano probe.

In order to study the response characteristics of pilot relief valve under high frequency alternating pressure in hydraulic excitation system, a mathematical model of pilot relief valve and AMEsim simulation model were established. The opening of pilot relief valve under high frequency alternating pressure was simulated and the simulation results were compared with experiment. The simulation results showed that the main valve port of the pilot relief valve opened abnormally under the alternating pressure and increased the energy loss of the system. The abnormal opening of the main valve port increased with the increase of the alternating pressure amplitude. When the alternating pressure frequency reached 200 Hz, the main valve port of the relief valve would not abnormally open. The experimental results were basically same with the theoretical analysis. It has important theoretical and practical significance for the pilot relief valve to be used under high frequency alternating pressure.

The new quasi-square honeycomb is one kind of transitional form of hexagonal honeycomb. It is of great significance to study its equivalent elastic parameters and vibration characteristics. The differences of the in-plane equivalent elastic parameters between the quasi-square honeycomb core with the double wall thickness and equal wall thickness were analyzed through the revised Gibson formulas. And the vibration performance of all edges simply supported quasi-square honeycomb sandwich structure with two different wall thickness under the influence of different equivalent elastic parameters was analyzed through the classic laminate theory. A finite element model of the quasi-square honeycomb sandwich structure with different wall thickness was presented to analyze its vibration characteristics, and the simulation results were compared with the theoretical analysis results. The results showed that the numerical simulation results of equivalent elastic parameters were basically in agreement with the theoretical values. Under the same basic structure parameters of the honeycomb, the in-plane equivalent shear modulus, out-plane stiffness and equivalent density of the quasi-square honeycomb core with double wall thickness were larger than those of the quasi-square honeycomb core with equal wall thickness. The natural frequencies of the quasi-square honeycomb sandwich structure with double wall thickness was lower than that of the honeycomb with equal wall thickness in the low-order vibration mode and higher in the high-order vibration mode. The influence of the three main impact factors on the natural frequency of the sandwich structure were listed in descending order as the yoz-plane equivalent shear modulus, the equivalent density and the wall thickness of the quasi-square honeycomb core. Study results indicat that the natural frequency of the quasi-square honeycomb sandwich structure calculated by the classic laminate theory has preferably coherence with the numerical simulation results. The correctness of the equivalent elastic parameters of the quasi-square honeycomb sandwich core obtained by the modified Gibson formula is further proved. This vibration theory is extended to the feasibility of calculating the general honeycomb sandwich structure, which lays a foundation for expanding the vibration characteristics of other types of honeycomb sandwich structures.

An automatic drilling & sampling device will be used for Chinese lunar exploration mission, particularly a hollow outer spiral drill will be used in order to penetrate the lunar regolith in 2 m depth continually. During the space environment, the flexure deformation increases by the additional load, such as the random vibration caused by launching or flighting of the spacecraft and the horizontal load caused by the drilling & sampling process, which complicates the load on the lunar sampling drill. What's worse, it can cause the fault of the exploration mission. Instead of redesigning the lunar sampling drill, an unlockable servo stabilizer was designed for the lunar sampling drill, comparing with the drilling stabilizer in the oilfield drilling technology on the earth. The stabilizer was consisted of the main body frame, the ball locking structure and the docking & locking structure. The main body frame could provide auxiliary support on the middle of the drill pipe in order to decrease the flexure deformation due to the vibration in orbit. When the drill had penetrated in a certain depth, the main body frame could be unlock by the ball locking structure and the docking & locking structure. The entire stabilizer penetrated with the lunar sampling drill, providing enough space for the penetration motion of the drilling and sampling system. Based on finite element method, the strength and stiffness of stabilizer had been tested. Combined with the drilling & sampling experiment with test article of the stabilizer, the unlockable servo stabilizer could improve the stiffness of the lunar sampling drill as an auxiliary support without obvious influence on the drilling & sampling process. The structure of the unlockable servo stabilizer operates well with sampling drill, which will improve the performance and reliability of the drilling & sampling process, and provide reference to improve the drilling & sampling system for Chinese lunar exploration mission.