Output Shaft Research Articles

Modeling and Validation of the Sealing Performance of High-Pressure Vane Rotary Actuator

The EHRA (Electro-Hydraulic Rotary Actuator), using a vane rotary actuator, has the advantages of a high torque density and integration and is expected to become a joint actuator for robots. This research focuses on the sealing characteristics of various parts of a vane rotary actuator. The average Reynolds equation was used to analyze the leakage characteristics at the gap. A detailed theoretical analysis was conducted on the internal leakage mechanism of a vane rotary actuator using an X-ring as the dynamic seal for the rotor vane. According to the path of internal leakage, different sealing forms are considered as a series or parallel, and the Newton iteration method is used to obtain the total internal leakage characteristics of a vane rotary actuator. It was also considered that the deformation of the vane rotary actuator caused a thicker gap, leading to an increase in internal leakage. The calculation results are consistent with the experimental data. The analysis results indicate that when estimating the internal leakage of a vane rotary actuator, it is necessary to take the pressure of the high-pressure chamber and output shaft position as inputs. This research provides a reference for an analysis of the method of internal leakage for vane rotary actuators. It provides theoretical support for designing a vane rotary actuator with more minor internal leakage and a higher volumetric efficiency.

Dynamic analysis of two-stage steering reducer for electric vehicle based on ROMAX

Abstract. With the rapid development of electric vehicles in the modern market, the efficiency and performance requirements of electric vehicle transmission systems are getting higher and higher. As an important part of the electric vehicle reducer, the steering reducer can make full use of the advantages of the two-stage deceleration transmission, achieve more efficient power transmission, and improve the acceleration performance and driving performance of electric vehicles. This paper aims to design a two-stage steering reducer for an electric vehicle, which adopts planetary gear transmission type. Firstly, the working principle of the electric vehicle steering reducer is analyzed, and the overall design scheme of the reducer is drawn up. Secondly, the transmission system parameters of the reducer are designed and calculated, including transmission ratio distribution, tooth number ratio calculation, etc. Secondly, the transmission structure of the reducer is designed, including input shaft, output shaft, first planetary gear train, second planetary gear train, reducer shell, bearing, etc., and the reducer model is drawn by three-dimensional software Solidworks. Finally, the strength and deformation check analysis of the two-stage reducer is carried out by using the finite element software ROMAX to evaluate the performance of the designed reducer under this working condition. The full text design has a certain reference, and can be applied to other electric vehicle reducer design to provide theoretical guidance.

Methodical and algorithmic aspects of mathematical modeling of a screw aircraft power plant

The article describes the solution of a scientific problem that consists in expanding the functionality of the program “Calculation of the traction-economic and mass-specific characteristics of the power plant and aircraft motion parameters” through the introduction of additional algorithms and mathematical models for calculating the altitude-speed characteristics of screw aircraft power installations. At the same time, an internal calculation of the aircraft propeller thrust is used according to experimental aerodynamic coefficients, which makes it possible to increase the efficiency and reliability of complex theoretical studies of power plants of various types as part of aircraft at the stage of external design. A description is given of the developed algorithms: an algorithm for converting power on the output shaft of a gas turbine engine into thrust of an aircraft power plant; a mathematical model of a propeller that provides calculation of its thrust from experimental aerodynamic coefficients; an algorithm for determining the thrust of the power plant, taking into account the compressibility of the air and the interaction of the propeller and the elements of the airframe of the aircraft. Some features of the mathematical modeling of an aircraft propeller are revealed, in particular, the principle of propeller control by influencing the blade angle and rotational speed depending on the aircraft flight speed and a method for constructing the field of aerodynamic characteristics of an aircraft propeller in a wide range of blade angle and speed coefficient. In conclusion, the results of verification of the modified program are presented with an analysis of the obtained altitude-speed characteristics.

A dual-stator threaded linear ultrasonic motor with preload mechanism.

The cylindrical ultrasonic motor, noted for its straightforward design, ease of miniaturization, and high precision, has significant potential in fields such as optics, healthcare, and precision engineering. However, miniaturization presents challenges, including diminished output force and complications in applying preloading stress. To address the reduced output force, this study presents a dual-stator, high-thrust cylindrical linear ultrasonic motor. This innovative motor features two stators, a mover, and a mechanism for applying preloading stress. A key design element is the parallel arrangement of the two stators along a threaded output shaft, separated by elastic components. This setup enables axial preloading via the threads' engagement. Simulations were conducted to refine the stators' parameters, assess their operational modes, and evaluate their in-plane paths. A prototype was subsequently built to test its impedance characteristics and mechanical performance. Test results showed that under a 200Vpp drive, the single-stator motor generated a maximum force of 4.3 N, while the dual-stator configuration produced 6.8 N. After applying preloading stress, the output force of the dual-stator motor increased to 9.4 N.

The Wear Behaviour of a New Eccentric Meshing Reducer with Small Teeth Difference

Eccentric meshing reducers are widely used in agriculture, industrial robots, and other fields due to their ability to achieve a high reduction ratio within a compact volume. However, the contact wear problem seriously affects the service performance of the eccentric meshing reducer, thereby limiting their range of applications. To effectively address this issue, this study involved a stress analysis of the contact pairs and a surface wear analysis of a new eccentric meshing reducer. The wear equation for the contact pairs was derived using Archard’s wear theory, incorporating geometric and material parameters from both the reducer gear contact pair and the spline contact pair. In parallel, a wear simulation was conducted by integrating the UMESHMOTION subprogram with ALE adaptive grids. Additionally, the effects of load amplitudes on contact pair stress and surface wear were systematically investigated. It is revealed that the contact pair stress of the reducer gear was higher than that of the spline contact pair. Furthermore, the internal spline exhibited the highest wear rate, followed by the output shaft gear, external spline, and input shaft gear, in that order. This work provides a comprehensive and in-depth understanding of the wear behaviors of general reducers with small teeth differences and offers valuable scientific references for design optimization, fault diagnosis, and maintenance strategy formulation.

Modelling width of the spectral component of a gas-turbine engine gearbox output shaft speed

Gearbox is the most stressed component in an aircraft gas-turbine engine. This implies the need for finding ways to monitor its technical condition. Practice shows that the most efficient method is vibration-based diagnostics. However, this method requires the use of sophisticated measurement systems and highly skilled personnel. This paper shows that errors of gear coupling manufacture and assembly, characteristics of machine operating mode, design factors, frequency modulation of the carrier of the engine rotor speed in the stationary mode of its operation, and wear of teeth flanks determine the width of the spectral component of the gearbox output shaft speed. Using the results obtained from the developed model of the width of gear tooth spectral component, ratios for width of the spectral component of the signal of the “standard” tachometric speed sensor of the gearbox output shaft speed and the corresponding spectral component of its vibration were obtained. Models for repaired and newly manufactured gearboxes and gearboxes with tooth flank wear were proposed. This allowed the development of a number of new diagnostic indicators of a defect. Several examples of the use of these new diagnostic indicators are given for the gearbox of one of turbo-prop engines. The results obtained provide an opportunity to assess the gearbox technical condition in operation.

Torque control of grasping force feedback using a series elastic actuator with an ultrasonic motor for a teleoperated surgical robot

In the context of teleoperated surgical robots, much research has been conducted into haptic feedback systems. Ultrasonic motors (USMs) are expected to be used as actuators for generating feedback torque because of their fast response and high torque–weight ratio. However, their nonlinear characteristics make control of the output torque difficult, leading to large spike-like torque errors during rotation reversal. One approach to counteracting this effect is to use series elastic actuators (SEAs). In this study, a force feedback system using an SEA with a USM was proposed. The spike-shaped errors in the output torque of the USM were reduced by up to 60 % by attaching an SEA to its output shaft. The dependence of the torque accuracy and the response time of the SEA on its spring constant were also examined. By introducing the SEA with a spring constant of 42.4 mN·m/°, it was indicated that the torque error of 14.8 mN·m and the response time of 9 ms could be simultaneously achieved. Finally, the force feedback system was applied to a teleoperated surgical robot, and the stiffness of the objects grasped by the robot was successfully fed back with the error of 0.65 % when grasping a sponge.

Theoretical characterization of the dynamics of a new planetary gearbox

Based on the newly designed planetary gear gearbox with reciprocating linear motion of its output shaft, research on its dynamic characteristics was conducted. The “kinematic mechanism method” was used to calculate the system’s transmission ratio, revealing its characteristic of having a relatively large transmission ratio. Combined with the calculation of transmission efficiency, the characteristic of high transmission efficiency was verified. The “velocity vector method” was used to calculate the relationship between the angular velocities of various components of the gearbox. By conducting a stress analysis on the planetary gear transmission system, the forces and torques acting on each component, as well as the meshing forces of the gears were calculated. The “central parameter method” was adopted to simulate the meshing contact between the gears in the planetary gear transmission system as undamped springs. Considering the two translational vibrations along the radial direction and the rotational twisting along the circumferential direction of each component, a translational-torsional coupled dynamic theoretical model of the system was constructed. Dynamic differential equations of the planetary gear transmission system were derived and solved to obtain the support forces and torques of each component at the bearing support positions, enhancing the research on the dynamic characteristics of the planetary gear transmission system.

Optimization and Analysis of Clutch Switching Timing for Hybrid Tractors Equipped with Hydraulic Mechanical Combined Transmission

The working environment of tractors is harsh and the working conditions are very complicated. To cope with this complex and changeable working environment, this paper presents a hybrid tractor powertrain loaded with hydraulic mechanical combined transmission (HMCVT). The powertrain can switch modes according to different operating environments. During mode switching, impact loads can cause wear and even damage to the transmission components. Interrupting the power transmission will reduce the tractor’s operational efficiency. In this paper, the orthogonal experimental range analysis method was proposed to optimize the quality of mode switching. Mode switching involves interactions between clutches. Orthogonal table L16 (215) was selected to design the orthogonal table head. SimulationX was used for simulation. Employing MINITAB range analysis yielded the optimal results. The simulations indicated a reduction in the output shaft’s velocity drop amplitude from 17.647% to 6.591%. The dynamic load coefficient decreased from 2.743 to 1.857. The impact strength was reduced from 14.125 to 5.67 m/s3. The switching time was reduced from 2.13 to 1.71 s. We built a model-in-the-loop (MIL) test platform to validate the results. The MIL test results were compared with the simulation results. Our findings indicate a degree of discrepancy between the simulated and the experimental results, yet the overall trends remain largely consistent. The correctness of the optimal scheme obtained from the orthogonal experiment is verified. This study provides a theoretical basis for the optimization of powertrain mode switching in hybrid tractors equipped with HMCVT.

Design and Test of Automatic Feeding Device for Substrate Filling

An automatic feeding device for substrate filling was designed to address the challenges of difficult feeding and low efficiency in the citrus seedling pot filling and transferring machine. The device comprises a framework, tracks, overturning frame, drive system, etc. In order to ensure optimal performance, the frame’s turning angle was set at a minimum of 110° and the angle between the frame’s horizontal plane and slope was determined to be 120°. Following optimization, the number and intensity of sudden changes in velocity, angular velocity, and thrust were reduced, thereby prolonging the device’s service life. The prototype test demonstrated that the device has an average feeding time of 9.86 s, is capable of raising 0.14 m3 of substrate in a single cycle, and has a handcart turning angle of 111°. Furthermore, no residual substrate remained in the handcart, and the handcart fixing mechanism operated correctly. The torque measurement results of the motor output shaft were found to be consistent with the simulation results in ADAMS, with a maximum force difference of only 298 N. The simulation was found to be accurate, with an error rate of only 3.67%. This model can be utilized as a dependable reference for the optimization of the design of the automatic feeding device.

Multidisciplinary design and optimization of journal bearing for high-power wind turbine speed increaser

With the increasing power of wind turbine generators (WTG), the failure rate of rolling bearings in wind turbines due to insufficient bearing capacity increases with the increase of bearing size. To overcome these challenges, this paper proposes a design optimization method for the rectangular groove elliptical sliding bearing (RGEB) of the WTG output shaft. This method can maximize the radial bearing capacity under the premise of ensuring that the oil film pressure is large, the end leakage and the temperature rise are small. The multidisciplinary design and modeling of RGEB are carried out according to the structure and working conditions of WTG. Based on computational fluid dynamics (CFD), the influence of the number of rectangular dynamic pressure grooves on the bearing performance is analyzed. The kriging model, BP neural network model, and SSA-BP model are constructed for each performance index of RGEB, to establish a high-precision combined surrogate model based on global error criterion. After establishing the optimization equation, the PSO and SQP combined optimization algorithm is used to optimize the optimal structural parameters. The results show that the bearing capacity of the optimized RGEB is 95.9% higher than that of the ordinary elliptical bearing (EB) without increasing the size and quality of the bearing. In addition, the combined surrogate model can effectively replace the expensive finite element model to deal with the WTG sliding-bearing optimization problem.

THE METHOD OF SELECTING THE MOST APPROPRIATE MODIFICATION OF THE MECHANISM USING COMPUTER TECHNOLOGIES

The article presents a method for identifying the most appropriate modification of the mechanism with the required output shaft rotation frequency by constructing various geometric models and calculation schemes. This technique based on the design and analysis of modification of the vibration stand mechanism for testing measuring equipment and products for vibration resistance and vibration resistance. The strength analysis of contact stresses and bending stresses in the engagement zone of the elements under various external and boundary conditions was performed using analytical and computer methods. A 3D geometric model of the parts is being created with the display of traces of operation on the surface of the parts, anticorrosion coatings, using materials of various heat treatment in the Compass 3D V.21 package. The most appropriate modification of the mechanism is identified by analyzing the distributions of maximum equivalent stresses according to Mises, the main stresses according to geometric models of parts. If these stresses exceed the limit values or the mechanism is underloaded, the geometric dimensions of the transmission parts should be changed, another material for the transmission parts should be selected and the strength calculations should be repeated.

An Analysis of the Kinematics and Dynamics Performance of a New Type of Three-Pronged Sliding Universal Coupling

The three-pronged sliding universal coupling is a new kind of three-pronged coupling. The purpose of this study is to demonstrate that, compared with a traditional unequal angular velocity universal coupling (such as the Hooke universal coupling), the universal coupling has the superior characteristics of constant angular speed transmission, simple structure and strong transmission capacity by performing kinematic and dynamic analysis of the new three-pronged sliding constant angular velocity universal coupling. It provides a broad prospect for applications in automotive and other fields. To study its kinematic and dynamic characteristics, directional cosine matrices are utilized as tools to analyze the coordinate systems by establishing simplified geometric models and corresponding motions. Through the analysis of the motions of the input and output shafts and employing the method of single-force element, a set of equilibrium equations for the forces acting on the output shaft and the input shaft are formulated for solution analysis. The research indicates that during the rotation process, there exists a small angular difference between the input shaft and the intermediate shaft, demonstrating the quasi-constant angular velocity characteristics of the new tripod sliding universal coupling. The curves of the forces and force moment acting on each component of the coupling approximate sinusoidal curves. The optimal operating angle range for the new tripod universal coupling is at angle , during which the system exhibits good transmission and mechanical performance. It can be widely used in the automobile industry, tie steel industry and other occasions that require angular transmission. It is especially used in high-speed operation and large transmission capacity.

Effect of a stranded hole type on the performance of corn stover composite pipe.

To promote the comprehensive utilization of corn stover and the development of field water-saving irrigation technology, a method of returning corn stover to the field was prosed; in this method, the crop stalks were crushed, mixed with soil in different proportions of adulteration, and then extruded to form hollow round tubes. To compare the influence of the winch blade with or without a diameter change on the composite pipe molding performance, two composite pipe molding devices were theoretically designed, simulated, and analyzed using discrete element simulation software, and a composite pipe molding bench test was performed. The simulation test revealed that the composite pipe molding rate of the winch blade without the reducer molding device was 3.45 kg/s, the output power of the winch shaft was 20.7 kW, the composite pipe molding rate of the winch blade with the reducer molding device was 1.20 kg/s, and the output power of the winch shaft was 18.75 kW. By calculating the weighted average of two indices, the composite pipe forming rate and the winch shaft output power, the comprehensive performance index of the composite pipe forming device without a reducer was greater than that of the device with a reducer. The composite pipe forming bench test revealed two kinds of molding devices with an extrusion molding with an outer diameter of 100 mm and an inner diameter of 30 mm. The composite pipe density test average was greater than 1.30 g/cm3 and met the requirements of composite pipe molding; the winch blade without a reducer molding device had an average composite pipe molding rate of 3.23 kg/s, and the winch blade with an average reducer molding rate of 2.07 kg/s. The forming rate of the composite pipe without a reducer was faster. Therefore, a winch blade without a reducer composite pipe molding device is more conducive to improving the composite pipe molding performance.

Structural Design and Dynamic Characteristic Analysis of Short-column Micro Piezoelectric Power Actuator

Background:: With the rapid development of science and technology, industrial products continue to develop towards the direction of lightweight and miniaturization, and the demand for power sources to drive micromachinery is increasing, so the patents related to microactuators are also increasingly valued. The microactuator based on a piezoelectric drive converts the deformation energy of the piezoelectric body into the kinetic energy of the transmission mechanism to drive the output shaft rotation. The stator and the rotor of the existing actuator are the surface contact with a certain preload force. After working for a long time, the contact surface will be lost due to friction, which will reduce the response speed and rotation accuracy and even cause the rotor to slip, affecting the actuator operating life. Objective:: In order to solve the above technical problems, the author innovates the driving mode between stator and rotor and proposes a novel short-column micro piezoelectric actuator based on multi-tooth alternating meshing transmission. Methods:: Firstly, the structure and operating principle of short-column micro piezoelectric power actuator, which can realize linear motion into rotary motion, and has three main advantages: compactness in size, multi-tooth meshing drive and large driving torque, are proposed and elucidated. Secondly, the structure size of each component of the actuator is determined to complete the 3D structure design. Thirdly, the modal analysis and the harmonic response analysis of the actuator are studied. The frequency range of the sawtooth wave voltage excitation signal applied to the actuator is determined. Finally, the prototype is made, and the performance test is carried out. Results:: In this paper, a micro piezoelectric power actuator different from the existing patent is proposed, which is assembled by a drive module, a transmission module, an elastic element, an output shaft, a base module and a shell. The results show that when the excitation frequency applied by the actuator is 157Hz, the amplitude of the tooth column along the axis of the actuator is 3.071mm, the axial amplitude of the output shaft is zero, and there is no axial motion. At this time, the displacement of the tooth column is the largest, and the driving performance is the best. From the experimental results, it can be seen that the prototype appears to have intermittent rotation under this frequency excitation. Conclusion:: The proposed micro piezoelectric power actuator adopts multi-tooth alternating meshing between the stator and the rotor to transfer power, which changes the transmission mode relying on friction in the existing technology, reduces the friction loss, avoids rotor slip, and improves the response speed, rotation accuracy and operating life of the actuator. The research work in this paper provides a new idea and a new method for the research and design of micromechanical power sources.

REDUCING THE KINEMATIC ERROR OF AN ECCENTRIC TRANSMISSION
 WITH A PARALLEL LOCATION OF INPUT AND OUTPUT SHAFT
 AS A RESULT OF THE APPLICATION OF A DOUBLE-FLOW LOADING SCHEME

The article presents kinematic diagrams and computer analysis of three types of eccentric transmission schemes.
 The graphical dependences of the kinematic error of the eccentric transmission are presented for the coaxial and
 parallel arrangement of the input and output shafts in two single-flow loading schemes. Computer analysis of an
 eccentric transmission with single-flow loading schemes showed that the kinematic error with the coaxial arrangement
 of the input and output shafts is 30 times lower than with the parallel arrangement of these shafts. In order to reduce
 the kinematic error of an eccentric transmission with a parallel arrangement of input and output shafts, a two-flow
 loading scheme was proposed. It has been established that the use of a double-flow loading scheme makes it possible
 to reduce the kinematic error by 12 times compared to a single-flow loading scheme with a load on the output shaft
 of 10 N∙m.
 It is planned to use the design of an eccentric transmission with a parallel arrangement of input and output
 shafts with several power flows when designing various types of gearboxes for cultivators.

Analiza porównawcza różnych wariantów montażu przeciwwag obrotowych na korbie nowego rozwiązania konstrukcyjnego zespołów pompowych bez żurawia

The article presents a comparative analysis of different variants of installing rotary counterweights on the crank in the mechanical drive of the new design of the pumping unit used in oil production. It also addresses the assessment of torque on the output shaft of the gearbox and the balancing coefficient of the mechanical drive. In examining the rotary balancing approach for the new design of the pumping unit, various options for installing counterweights on the crank during rotary balancing were analyzed. Analytical expressions were proposed to determine the torques on the output shaft of the gearbox. Calculations based on the technical parameters of classic pumping units of the СK series revealed that the installation of counterweights on the crank during rotary balancing in the new design of the beamless pumping unit machine significantly affects the torque on the output shaft of the gearbox and the balancing of the pumping unit. They also revealed that although the torque on the output shaft of the gearbox is small in the pumping unit equipped with two counterweights of the same weight and located at the same distance, in this configuration, the output shaft of the gearbox experiences a substantial cantilever load due to excessive weight of the counterweights, leading to a significant reduction in the durability of the gearbox. In the other two options, when installing a single counterweight on the crank, the torque on the output shaft of the pumping unit’s gearbox is approximately from 5 to 10% greater than in the first variant, resulting in additional energy losses. In the pumping machine equipped with two counterweights of equal weight but located at different distances from the center of rotation, the torque on the output shaft of the gearbox is reduced, similar to the first variant. However, due to the weight of the counterweights, it also imposes a substantial cantilever load on the output shaft, leading to a significant reduction in the service life of the gearbox. Additionally, in this option, unlike the first, the balancing coefficient is approximately 3% less.

Синтез схем навантаження силових елементів кулько-гвинтового гідропідсилювача з аксіальною структурою приводу

The well-known design of ball-screw hydraulic power steering is not without flaws - the bearing supports of the output shaft are the most loaded elements of the unit structure, and the elastic deformation of these supports, during operation, is the reason for the depressurization of the sealing system in this area. The purpose of the work is to determine the layout of ball-screw hydraulic power steering with a steering arm, using which it is possible to ensure the maximum beneficial effect from the use of a system of active unloading of the rolling bearings of the shaft sector, increasing the load-bearing capacity and ensuring better tightness. The study is based on the provisions of the theory of resistance of materials. The paper examines and compares the two most common configurations for the location of the steering arm's longitudinal axis relative to the cavity of the gear shaft: coaxial and perpendicular location. To achieve the goal, an analysis of the interaction system of the output shaft of the ball-screw hydraulic power steering with rolling bearings, steering arm, and rack and pinion transmission was carried out for the given two configurations. The operating conditions of the output shaft, under its load, and the reactions of the supports are described by systems of equations. For the purpose of comparative evaluation of the ratio of the reactions of the supports depending on the load and taking into account the real linear dimensions of the parts, a methodology and a number of assumptions have been developed in the work. With the help of the developed methodology, a relative comparison of the layout configurations studied in the work was carried out, taking into account the direction of rotation of the output shaft of the ball-screw hydraulic power steering with the steering arm installed. As a result of the study, the composition of the ball-screw hydraulic power steering with steering arm was determined, which allows to ensure the maximum beneficial effect of the use of the system of active unloading of the rolling bearings of the shaft sector. The use of the steering arm installation scheme, in which the longitudinal axis of the arm is located coaxially relative to the cavity of the gear shaft, creates prerequisites for the development, in the future, of an active system for unloading the rolling bearings at the points of the bearing reactions. Such a system can be implemented, for example, due to the use of hydraulics elements, thereby ensuring an increase in bearing capacity, reducing the load on the output shaft rolling support elements and reducing the impact of this load on the tightness of the unit.

Study on the dynamic characteristics of planetary gear transmission mechanism of metal cold rolling mill

Using the parametric modelling feature in Solidworks software, a three-dimensional solid model of a planetary gearbox with linear reciprocating motion of the output shaft was constructed. By conducting theoretical calculations related to the kinematics of the transmission system and combining Adams virtual prototyping simulation technology, a dynamic simulation model of the planetary gear transmission mechanism was established to analyse the motion laws and dynamic characteristics. The simulation results were compared and analysed against the theoretical calculation results, and they showed good agreement and consistency. The study also investigated the impact of counterweights on the inertia forces and moments of the output shaft in the transmission mechanism. The results indicated that adding counterweights effectively reduced the inertia impact caused by inertia forces at the start and end positions of the stroke, as well as the inertia torque caused by changes in angular acceleration during the startup and stopping phases, thereby enhancing the smooth operation of the mechanism. Additionally, different thicknesses of counterweights had varying effects on balancing the inertia forces and moments of the output shaft. The study aimed to find the optimal thickness of counterweights to achieve the best balance effect. Furthermore, the study examined the influence of different speeds of the driving gear on the inertia forces of the output shaft. The results showed that at a driving gear speed of 1500 rpm, the horizontal thrust generated by the output shaft was 63566 N, which could provide the required thrust for the rolling mill operation, and the inertia forces of the output shaft tended to stabilize.

A semi-implicit homogeneous discretized differentiator based on two projectors: experimental validation on a cable-driven parallel robot

This work is dedicated to the application of a semi-implicit homogeneous differentiator to estimate the angular velocity and the angular acceleration of each of the eight electric motors of the CRAFT cable-driven parallel robot from the recording of the angular position of their respective output shaft. These motors drive the winding or unwinding of eight cables to move the robot moving-platform. The results show that this differentiator, whose the definition is respectively based on two projectors, is an extremely efficient tool for estimating the angular velocities and accelerations of the eight motors. These estimated velocities and accelerations are much less noisy than their reference signals obtained by backward difference. Moreover, the estimated quantities obtained with this differentiator are successfully compared to those obtained by a non-linear observer based on the interpolation and numerical difference of the measured position variable. Those promising results will definitely contribute to a better control of the CRAFT robot.