Cylindrical Cam Research Articles

Development of a novel cylindrical cam shaking table for geotechnical centrifuge modelling

The use of dynamic centrifuge modelling has substantially risen over the years for investigating failure mechanisms, studying the physics-based mechanics of soil structure systems, and validating numerical tools. Nevertheless, the primary issues associated with the use of servo-hydraulic actuators (presently the prevailing shaking table for a geotechnical centrifuge) are their exorbitant expense, intricate operation, and shaking control. This paper describes the development of a novel cylindrical cam shaker for the newly installed Mark III geotechnical centrifuge facility at Tokyo City University. The cylindrical cam mechanism is activated once the desired voltage is applied via the electrical slip rings. The rotation of the cylindrical cam is translated into the linear motion of the follower plate which then moves the shaker linearly back and forth. A stepwise procedure is developed to determine the voltage required to drive the shaker and achieve the desired earthquake characteristics for a given payload mass and centrifugal acceleration. The performance of the shaker was systematically assessed through a series of dynamic centrifuge experiments at different centrifugal accelerations and payload masses. Finally, the excellent capabilities of the developed mechanical shaker in terms of the repeatability of the base motions were demonstrated using a model example.

Cylindrical-cam modulation instantaneous angular speed sensor for reciprocating-rotary machine

This paper presents the theory and implementation of a novel sensor system for measuring the instantaneous angular speed (IAS) of a shaft with reciprocating rotary motion. The system comprises a laser displacement sensor and an S-shaped cylindrical cam sleeve fixed to the shaft. As the shaft rotates with reciprocating rotary motion, the cylindrical cam modulates the IAS signal of the machine to achieve a change in profile radius. The signal is then demodulated to obtain the IAS of the reciprocating rotary motion. The sensor system is experimentally validated using a vibration-assisted tapping machine. Results show that the IAS readings are consistent with the machine’s set parameters. Furthermore, the novel sensor produces considerably smooth and stable traces of the IAS, demonstrating its high accuracy and reliability in obtaining the IAS of reciprocating rotary motion transients. The frequency error rate of the system is less than 3%, and the highest resolution of the angular amplitude is 4.788″. Finally, a cutting experiment confirmed the feasibility and validity of the proposed sensor system in optimizing the parameters of the vibration-assisted tapping machine.

Cylindrical cam mechanism design with visual basic

One of the technology products that have taken an important place in our lives from the past to the present is power and motion transfer elements. Power and motion transfer elements are very important for users in terms of facilitating work transfer, easing the workload based on people and ergonomics. One of the basic building blocks of these transmission systems is cam mechanisms. Cam mechanisms consisting mainly of followers and cams; It performs a complementary task by transmitting the follower's movement to the cam assembly by direct contact. While cam mechanisms lighten the work load, it is a frequently preferred system because it takes up little space and contains few parts and allows for a wide range of movements. However, sensitivity to vibration and sudden shock effects and cost problems have led to the development of manufacturing methods of cam mechanisms. In this master's thesis, design and mathematical information about cam mechanisms and cylindrical cam mechanisms are given, and the design of a cylindrical cam mechanism with a vertical multiple output limb was carried out using computer-aided drawing programs Solidworks and Autocad. The use of multiple output limb cam mechanisms is increasing day by day in terms of the width of the work area and the possibility to work with other machines. For this reason, this work is intended to be a guide resource for the reader in industry and science for both cam mechanisms and cylindrical cam mechanisms. Microsoft Excel and Visual Basic programs were used in the calculations and designs, and the design details of the mechanism were revealed with the data and formulas entered into the program.

Mathematical modeling on a novel manufacturing method for roller-gear cams using a whirl-machining process

The whirl-machining process is a precise, efficient, and promising machine process for manufacturing workpieces over the milling process. At the same time, the roller-gear cam has advantages over the other cam-follower system. However, the whirl-machining process has not been applied to manufacture the roller-gear cam. Therefore, this paper proposes a novel method for roller-gear cam manufacturing using a whirl-machining process. Mathematical modeling is described for generating the roller-gear cam, roller, and whirl-milling tool surface. A novel CNC machine and its coordinate system are proposed. Cutting simulations for obtaining the surface topologies and normal deviations are conducted. Globoidal cam with different cylindrical rollers, globoidal cam with a conical roller, and cylindrical cam with a conical roller are taken as case studies, and results are discussed. A virtual cutting simulation was conducted using VERICUT. Some machining examples are shown to verify the benefits of the proposed method in roller-gear cam manufacturing.

Design and application of a biconjugate closed-end cylindrical single-cam pair

A biconjugate closed-end cylindrical single-cam pair refer to a cylindrical cam pair that control two roller followers. Based on the theory of space conjugated surface and vector revolving, by analyzing the conjugation relation between two rollers and cam surfaces of a biconjugate closed-end cylindrical single-cam pair, the parameter equations of the moving path of the axis of the left and right rollers that envelope the cam surface are established. Taking the minimum clearance between the roller and cam surfaces as the optimization objective, the parameter equation was optimized by adjusting the coefficient of the parameter equations of the left and right rollers without changing the structural size of the cam pair, and the optimized equation can be directly used as the tool path of cam machining. Finally, the cam was machined by a 5-axis NC machining center, and the optimized effect was verified by measuring the clearance between the work face of the cam and the rollers after the assembly of the cam, swing rods, and other parts. The obtained results showed that the clearance between the work face of cam and rollers were significantly reduced after optimization, indicating that the optimization method of cam is reasonable.

Development of a Simulator Capable of Generating Age-Specific Pulse Pressure Waveforms for Medical Palpation Training

With the emergence of the metaverse and other human–computer interaction technologies, promising applications such as medical palpation training are growing for training and education purposes. Thus, the overarching goal of this study is to develop a portable and simple pulse pressure simulator that can reproduce age-specific pulse pressure waveforms for medical palpation training. For training applications, the simulator is required to produce accurate radial pulse waveforms consistently and repeatedly. To this end, exploiting the cam-based pneumatic pulse generation mechanism, this study intends to develop a cylindrical (or 3D) cam whose continually varying surface contains a wide range of age-related pulse pressure profiles. To evaluate the performance of the simulator, the reproduced pulse waveforms were compared with approximate radial pulse pressure waveforms based on in vivo data in terms of the augmentation index (AI) and L2 error. The results show that the errors were less than 10% for all ages, indicating that the proposed pulse simulator can reproduce the age-specific pulse waveforms equivalent to human radial pulse waveforms. The findings in this study suggest that the pulse simulator would be an excellent system for RAPP palpation training as it can reproduce a desired pulse accurately and consistently.

Behavior of maize grains on the three-dimensional translational vibrating sieve

To improve the working efficiency of the cleaning device for maize mixture with a large feeding mass and to realize rapid dispersion of the maize grains on the sieve, a sieve with three-dimensional translational motion was designed based on a cylindrical cam. CFD-DEM (Computational Fluid Dynamics and Discrete Element Method) was used to investigate the motion of materials on the three-dimensional translational vibrating sieve (3TVS). The results show that the dispersion degree of transverse velocity of particles (DTVP) is correlated with the radius and rotation speed of the cam table and the height of the cylindrical cam positively. It is increased compared with the planar reciprocating vibrating sieve (PRVS). The effects of different factors on 3TVS cleaning device were obtained. This study provides a reference for designing a multidimensional-motion sieve for a large feeding-mass grains cleaning.

Применение бурильных машин с ударным кулачковым механизмом в различных горно-геологических условиях

Purpose. The article is devoted to the search and analysis of well-known technical solutions of drilling machines equipped with a cam impact mechanism, according to the results of which fundamentally new scientific tasks are set related to the substantiation of the design parameters of the impact unit of the drilling machine, providing the possibility of automatic adaptation of drilling modes in changing mining and geological conditions. Research methods. To implement the impact of the tool on the rock, a cam mechanism is built into the design of the machine, which provides the generation of a given impact energy. Cam mechanisms are represented by a wide variety, among which the most suitable for equipping impact drilling machines is a cylindrical end cam mechanism in which the leading link – the cam performs a rotational movement, converted into a reciprocating motion of the output link – the pusher-striker. Rational cam profiling makes it possible to implement a certain law of pusher motion with a sufficient degree of accuracy, and, consequently, to solve the problem of choosing the optimal impact energy. Research results. Based on the results of the critical analysis of the structural schemes of the above machines and mechanisms, new research tasks are being set for science and practice, the implementation of which will allow obtaining new scientific knowledge in the field of the use of cam mechanisms in impact drilling machines. Conclusions. The use of impact cam mechanisms of a special structure and geometry makes it possible to realize the idea of creating a drilling machine capable of automatically adapting operating modes to operational mining and geological conditions.

Study of Fault Identification of Clearance in Cam Mechanism

The clearance between the main roller and the cylinder cam has an important impact on the operational status of the bolt. In order to achieve the clearance and recoil of the cylinder cam mechanism, a bolt model was built and studied. The leading dynamic roller group and the dynamic bolt were analyzed. Positive stress and friction force change quickly on the high-speed leading roller group, influencing multiple aspects. When the main roller suddenly rotates or reverses in several short intervals, the assembling clearance and the massive friction force between the main roller and the cam curve slot are the main wear factors in theoretical analysis and test experiments. The leading roller group, the pure rolling criterion of the cylindrical cam mechanism of the automaton, is derived in this paper. Moreover, a new fault diagnosis method is developed, based on the Variational Box Dimension Kernel Fuzzy Mean Clustering Algorithm (VK) algorithm, which combines the variational mode decomposition and fractal box-counting dimension (VMD-FBCD) and the fuzzy clustering algorithms with a kernelized Mahalanobis distance (KMD-FC). With the simulation validation from 2810 samples, diagnosis using the VK algorithm is found to have a higher accuracy rate and slightly lower fallacy rate and to be faster than other diagnostic methods of similar studies. The results in terms of the recoil cylinder cam mechanism’s multi-body dynamic analysis and high-speed fault identification also have significance as a reference for solving similar problems.

Research on an Efficient Deep-Hole Application Method for Liquid Fertilizer Based on Alternate Drilling

Liquid fertilizers are mainly applied by spraying liquid fertilizer on the surface of crop leaves and by deep openings between rows. The first causes considerable environmental pollution, and the second can easily cause to damage the root system of crops. In this study, corn crops were taken as the study object and an efficient deep-hole application method for liquid fertilizer based on alternate drilling was proposed. The needle body is driven by the spur gear wheel system in a caving mechanism to puncture holes alternately in a vertical posture and high-speed punctures are implemented with less disturbance to the soil. The cylindrical hollow cam of the mechanism is controlled so that the fertilizer needle sprays fertilizer when injected into soil and stops injecting when pulled out of the soil. Based on the bench test, fertilizer injecting performance and energy saving performance of the differential two-way fertilizer supply distribution device were analyzed and the head loss for energy saving value is 2.1, 3.1, and 5.5 m. Based on numerous field tests, the puncture track, hole width, and hole spacing are analyzed under different puncture speeds. Field tests were carried out according to a quadratic orthogonal rotating combination design and the results show that when the fertilization depth for agronomic requirements is 80 mm and the machine work speed and forward speed are 127 r min−1 and 1.40 m s−1, respectively, the hole width is 39.9 mm, the hole spacing is 320 mm. The efficient deep-hole application method for liquid fertilizer based on alternate drilling can provide support for data analysis and theoretical design of liquid fertilizer deep application technology for corn crops.

A pneumatic rotary actuator for forceps tip rotation

In this study, we propose a small rotary actuator mounted on the tip of a forceps manipulator for laparoscopic surgery. The proposed actuator comprises a soft actuator (SA) and a cylindrical cam mechanism that converts linear motion into rotary motion. The SA is made from silicone and driven pneumatically. Therefore, it is lightweight, inexpensive, and highly biocompatible. Using an SA, the entire rotary actuator can be made lighter and smaller. In addition, the actuator has the advantage of easy sterilization and disposability due to the absence of electrical parts in it. Furthermore, using air as the power source, one can control the rotation angle with only a simple control that is not affected by the forceps posture. In this study, we developed a prototype of the SA and measured its basic characteristics. Subsequently, we mounted the SA on the proposed rotary actuator and confirmed the basic characteristics of the actuator through cyclic motion and force measurement experiments. As a result of the experiments, a rotational angle of 70° or more was measured and the target motion range was achieved. In addition, we confirmed that the rotary actuator exerted a maximum torque of 3.0 N mm, which was sufficient for the needling task on a silicone seat.

Structural design and mechanical analysis of a new equipment for tire vulcanization

Vulcanization is a pivotal process of tire manufacturing, endowing the uncured tire with exquisite surface pattern and superior performance by converting rubber property from plasticity to elasticity. However, the defects of incomplete expansion, asymmetric structure, and vapor condensation deposition in the existing vulcanization technology inferiorly affect the uniformity and dynamic balance performance of tires. In our paper, a novel tire curing equipment, i.e., vulcanized inner mold drum (VIMD) is designed to improve the traditional vulcanization process for automobile tires. The structure design of the drum tiles, the telescopic mechanism and the transmission mechanism, and the finite element simulation analysis and reliability check of the key components are carried out. The contraction ratio is obviously increased by increasing the number of drum tiles and adopting the structural design method of arranging the link mechanisms cross-symmetrically. The ingenious design of the dual cam link mechanism enables the movement of the mechanism to proceed in an orderly manner, effectively avoids complicated controlling design. The design of self-locking structure considerably reduces the force of the links and improves the overall dimensional accuracy. The results suggest that the VIMD has excellent dimensional accuracy and structural stability. Highlights A new type equipment for tire vulcanization is proposed. The contraction ratio is obviously increased by increasing the number of drum tiles, and adopting the structural design method of arranging the link mechanisms cross-symmetrically. The ingenious design of the cylindrical cam track enables the movement of the mechanism to proceed in an orderly manner, effectively avoiding the interference of parts. The design of the dual cam link mechanism avoids complicated controlling design and effectively improves space utilization. The design of self-locking structure considerably reduces the force of the links and improves the overall dimensional accuracy.

Models of a hybrid wheeled hopping self-balanced robot

Combining wheeled structure with hopping mechanism, this paper purposes a self-balanced hopping robot with hybrid motion pattern. The main actuator which is the cylindrical cam, optimized by particle swarm optimization (PSO), is equipped with the motor to control the hopping motion. Robotic system dynamics model is established and solved by Lagrangian method. After linearization, control characteristics of the system is obtained by classical control theory based on dynamics equations. By applying Adams and Matlab to simulate the system, hopping locomotion and self-balanced capability are validated respectively, and result shows that jump height can reach 750 mm theoretically. Then PID control scheme is developed and specific models of hardware and software are settled down accordingly. Finally, prototype is implemented and series of hopping experiments are conducted, showing that with different projectile angle, prototype can jump 550 mm in height and 460 mm in length, transcending majority of other existing hopping robots.

Stresses and deformations of an eccentric cylindrical cam during hydro-joining

The stresses and deformations of an eccentric cylindrical cam during the process of hydro-joining have been calculated in orthogonal curvilinear coordinates according to the mechanical model of the cam and governing equations in terms of appropriate complex potentials with suitable boundary conditions. The radial and shearing stress coefficients determined for an example cam are far less than that of the tangential stress during hydro-joining. The tangential stress coefficient of the outer surface of the cam is greater than that of the internal surface when the polar angle exceeds a particular value. The position of the maximum value of the radial stress coefficient is located on the internal surface of the cam, and the maximum shear stress coefficient is located between the inside and outside surfaces of the cam. The cam deformations on the internal and external surfaces under internal pressure respectively attain maximum values at particular angles. The maximum values of the radial and y-directional deformations are located at the position of the minimum wall thickness. The radial deformations determined for an example cam are far larger that the tangential deformations during hydro-joining. The errors between the theoretical and numerical solutions for the tangential stress and the y-directional deformation are both very small.

A high-stability triboelectric nanogenerator with mechanical transmission module and efficient power management system

The triboelectric nanogenerator (TENG) has been demonstrated to be a promising technology for harvesting mechanical energy and powering electronic devices. However, it is difficult to make TENG output stable because of the irregular movement of actual mechanical sources in the environment, and the inefficient energy utilization limits its application. In this study, we propose a contact-separation TENG (CS-TENG) integrated with a mechanical transmission module and its optimal power management system. Firstly, a gear and cylindrical cam mechanism is designed in the mechanical transmission module, which respectively increases the working frequency of CS-TENG and makes the output stable. Secondly, a control module is developed in the PMS to accurately control a switch for extracting maximum output energy, and a series of simulation and experiments have been done to further study the effect of control parameters on the energy extraction process. In the control module, a differential circuit is used to detect the peak of the output voltage. It is found that an optimum differential resistance can increase the detection accuracy and reduce external interference. A time-delay circuit is used to accurately control the switch-on time. As the switch-on time increases, the energy extraction efficiency first increases and then decreases. Finally, the energy extraction efficiency of PMS reaches to 37.8% with the optimal control parameters. We not only solve the problem of the irregular output of TENG, but also provide a guidance for optimizing the design of self-powered system.

Fault mode analysis and reliability optimization design of a mechanical interface based on cylindrical cam mechanisms

The mechanical interface has the characteristics of low shock and vibration, and is emphasized in the aerospace and ocean engineering fields. In this paper, a mechanical interface based on coupled cylindrical cam mechanisms is designed. It can achieve the expected functions, but there exist faults in some times. The fault modes and causes of the interface are firstly analyzed. Then a design approach based on Monte Carlo simulation is presented for analyzing and optimizing its reliability. According to the fault modes, the performance functions of the interface are established for obtaining the optimal scheme. A case is given to illustrate the proposed method. The simulation results and the prototype experiments prove that the optimization scheme effectively improves the reliability of the interface, and has better performance than the original one.

Parametric Design and Numerical Control Simulation of Cylindrical cam Based on Ug8.5

This paper introduces the method and process of parametric modeling and numerical control programming simulation processing of cylindrical cam by using ug8.5 software, improves the design, manufacturing efficiency and precision of cylindrical cam, and realizes the serial design of cylindrical cam. It has been proved by practice that the performance of cylindrical cam is stable and efficient, which greatly shortens the machining cycle of cam and improves the efficiency.

Cylindrical Cam Electromagnetic Vibration Damper Utilizing Negative Shunt Resistance

Two common problems in utilizing electromagnetic dampers are addressed in this article. The first problem is the maximum available damping that can be created in an electromagnetic actuator using a positive resistive load. Maximum damping is achieved when the motor terminals are placed in a short circuit configuration, but it might not be enough in certain applications. As a solution, a method to produce negative resistance using power electronics and control techniques is presented in this article. The negative resistance cancels part of the resistance of the electromagnetic machine, which leads to producing larger electrical current in the actuator coils. As a result, higher damping levels are generated. The other contribution of this article is devising an effective motion rectification mechanism for converting the translational motion into rotary motion that drives an electric machine. To this end, a cylindrical cam mechanism is proposed which can provide longer strokes while keeping the geometry and size of the damper similar to the axial dampers used in automotive and bicycle dampers. The mechanism shows longer values for the ratio of stroke to maximum length compared to other designs reported in the literature.

Design and Simulation Analysis of Seedling Picking Mechanism of Pot Seedling Transplanter

Aiming at the problems of complicated structure, difficult processing and high cost of transplanting mechanism of pot seedling transplanting machine, this paper develops a kind of crank and rocker type transplanting mechanism. The mechanism consists of transplanting arm, eccentric wheel, connecting rod and cylindrical cam seedling clamp. This paper analyzes the working mechanism of the seedling picking mechanism, and establishes the geometric relations among the components by selecting the appropriate parameters of the seedling picking and releasing points of the crank and rocker mechanism. A set of optimal solutions are solved iteratively by using the software of Matlab. Meanwhile, the cam mechanism used to control the opening and closing of the seedling clamp is designed by using the geometric characteristics of the seedling clamp and the periodic characteristics of the seedling clamp, and the results of Matlab are modeled in SolidWorks and imported into Adams for virtual simulation analysis. The analysis results showed that the seedling clamp could reach the pre-set position to pick and release seedlings smoothly through the movement of the seedling picking mechanism, which verified the correctness of the mathematical model of the seedling picking mechanism.

Design details of the HP3 mole onboard the InSight mission

The HP³ Mole system is part of the HP³ payload on the InSight discovery class mission, which will place a geophysical lander onto the surface of Mars in 2018. DLR's HP³ - instrument (Heat Flow and Physical Properties Package) will measure Mars' interior heat flux and thermal gradient down to a depth of 5 m and thus penetrates deeper below the Martian surface than any other instrument before. Being the locomotion system of the instrument, the HP³ Mole acts as a self-impelling nail in order to accomplish this goal. The inner hammering mechanism is spring driven and periodically loaded by a cylindrical cam mechanism. The innovative impact driven locomotion principle enables a minimum in required energy and mass, but leads to complex system behaviour and dependence of the inner mechanism dynamics on the outer force conditions exerted by the soil.The scope of this paper is to provide an overview of the Mole, its role in the mission and payload, as well as to give a brief overview about its subsystems, its interfaces and working principle.