Kinematics Analysis of Incomplete Gear and Rack Pumping Unit

A pumping unit with incomplete gear and rack reversal was designed for smooth motion and low energy consumption. This paper first describes the working principle of the pumping unit. The kinematical equation of the pumping unit is established on the basis of analyzing the kinematic relationship between the first tooth meshing area, the normal meshing area and the final tooth meshing area of incomplete gear and rack. The kinematic relationship curve of the pumping unit is obtained by ADAMS simulation. The simulation results show that the theoretical model is correct. By comparing the results with the conventional pumping unit, it can be seen that: the pumping unit has a smooth movement of the up-down strokes, with fluctuations of movement only in the process of changing directions. The incomplete gear and rack drive is smooth, which can improve the kinestate of the pumping unit.

Design and Kinematics Analysis of Suspension System for a Formula Society of Automotive Engineers (FSAE) Car

The main objective of the Suspension of a vehicle is to maximize the contact between the vehicle tires and the road surface, provide steering stability and provide safe vehicle control in all conditions, evenly support the weight of the vehicle, transfer the loads to springs, and guaranteeing the comfort of the driver by absorbing and dampening shock. This paper discusses the kinematic design of a double a-arm Suspension system for an FSAE Vehicle. The hardpoint’s location can be determined using this procedure to simulate motion in any kinematic simulation software. Here, Optimum Kinematics is used as kinematic simulation software, and the results are verified using Msc Adams simulation. The method illustrated deals with the basics of Kinematics which helps to predict the characteristics of the Suspension even before simulating it in the kinematic simulation software.

Design of a Payload Adjustment Device for an Unpowered Lower-Limb Exoskeleton

This paper proposes a device that can change the payload of an unpowered lower-limb exoskeleton supporting the weights of humans and loads. Our previous exoskeletons used a cam–follower structure with a spring applied to the hip joint. This exoskeleton showed satisfying performance within the payload; however, the performance decreased when the payload was exceeded. Therefore, a payload adjustment device that can adjust the wearer’s required torque by easily applying it to the cam–follower structure was developed. An exoskeleton dynamic equation that can calculate a person’s required joint torque given the required payload and the wearer’s posture was derived. This dynamic equation provides a guideline for designing a device that can adjust the allowable joint torque range of an unpowered exoskeleton. In the Adams simulation environment, the payload adjustment device is applied to the cam–follower structure to show that the payload of the exoskeleton can be changed. User convenience and mass production were taken into account in the design of this device. This payload adjustment device should flexibly change the payload of the level desired by the wearer because it can quickly change the payload of the exoskeleton.

Assembly Variation Analysis of Incompletely Positioned Macpherson Suspension Systems Considering Vehicle Load Change

The assembly precision of wheel alignment parameters is vital to vehicle handling stability. Due to the vertical wheel displacement and compliant components in suspension systems, it is difficult to assemble qualified vehicles with proper wheel alignment parameters. In the assembly shop of the automobile factory, the adjustment of wheel alignment parameters is the most time-consuming process because it relies on trial and error. In order to provide a theoretical guidance to the precision control of wheel alignment parameters, this paper extends the theory of equilibrium equations of incremental forces (EEIF) to 3D compliant mechanisms. Constraint equations of kinematic joints are adopted to express the spatial relationships of different parts. A couple of fixed and floating joint coordinate systems (CSs) are used together to represent deviations of compliant components. The impacts of suspension part deviations on vertical wheel displacement and assembly deformations are well illustrated by such approach. Accuracy of the proposed method is verified by comparing with ADAMS simulation. The results show that the error rates of the 3D EEIF method are less than 5%. Furthermore, statistical assembly variation analysis of a Macpherson suspension is accomplished by using the proposed method and an optimized process strategy is put forward.

Analysis of Stress, Strain, and Fatigue Strength of the Rotary Table of Boom-type Roadheaders

The rotary table is the key component in the optimal design of roadheaders. In this study, a simulation model of the cutting part and a rotary table is established in SolidWorks, and stress analysis and strength evaluation of the structure of the rotary table are performed. To this end, finite element analysis is performed on the basis of the dynamic theory of a coupled multibody system comprising rigid and flexible bodies. Considering actual working conditions, the load file of the cutting head is calculated based on the development of the “Roadheader Machine load Calculation Program”, and the stress and strain cloud map of the cutting head running to the bottom left, middle end, and right end of the rotary table is obtained through Adams simulation. Then, the 6-order modal analysis is carried out, and the S-N curve of the turntable is finally established. In addition, the fatigue life reliability of the turntable is analyzed using the AWE fatigue module. The results show that, provided reliable working conditions, the EBZ160 type roadheader machine during the normal service life shows no risk of fatigue failure under normal working load.

Analysis of Stress, Strain, and Fatigue Strength of the Rotary Table of Boom-Type Roadheaders

The rotary table is the key component in the optimal design of roadheaders. In this study, a simulation model of the cutting part and a rotary table is established in SolidWorks, and stress analysis and strength evaluation of the structure of the rotary table are performed. To this end, finite element analysis is performed on the basis of the dynamic theory of a coupled multibody system comprising rigid and flexible bodies. Considering actual working conditions, the load file of the cutting head is calculated based on the development of the “Roadheader Machine load Calculation Program”, and the stress and strain cloud map of the cutting head running to the bottom left, middle end, and right end of the rotary table is obtained through Adams simulation. Then, the 6-order modal analysis is carried out, and the S-N curve of the turntable is finally established. In addition, the fatigue life reliability of the turntable is analyzed using the AWE fatigue module. The results show that, provided reliable working conditions, the EBZ160 type roadheader machine during the normal service life shows no risk of fatigue failure under normal working load.

Dynamic Characterization and Modeling of Flexure Based Planar Mechanism

This paper investigates design, modeling and fabrication of a flexible five bar mechanism, which incorporates large deflecting flexure hinges attached to rigid links. This 3D printed flexible robotic mechanism is actuated by two servo motors and machine vision is used to obtain its tip position information. Detection of parts accomplished using color thresholding of a dynamic region of interest, while the position of detected elements is measured using the pinhole camera model. Under the assumption of non-small length flexures, where low aspect ratio is not satisfied, we adopt an initially curved pseudo rigid body approach to model each flexure as two rigid links that are pinned on top of each other using torsional springs, which capture the load-deflection behavior of the compliant flexures. Kinematic and dynamical equations are derived using both vector closure loop equations and Euler’s Laws of Motion. Adams simulation is performed by exporting the CAD model as a parasolid file, defining revolute joints and input motions and converting the rigid body to flexible. Mathematical model is validated using both the experimental data and Adams simulations.

Study on the Vibroimpact Response of the Particle Elastic Impact on the Metal Plate

In order to study the contact and vibration response in the reciprocating impact between coal gangue particles and metal plate, on the basis of the Hertz contact theory, L-N contact model, and the Lagrange equation, this paper established an impact-contact model when the particles free falling to vertically impacts on the metal plate. The variable damping simulation method is proposed, and the accuracy of the variable damping simulation in the medium reciprocating collision is verified by combining the constant damping simulation, the variable damping simulation, and the falling body impact-contact model. The functional relationship between the damping term and the initial impact velocity in Adams simulation is also obtained. Then, through the rigid-flexible coupling method which is combined by Adams and Hypermesh, the three types of variable damping simulations are conducted: the simulation that the free-falling rigid rock sphere impact on the rigid metal plate, the simulation that the elastic rock sphere impact on the rigid metal plate, and the simulation that the elastic rock sphere impact on the elastic metal plate, respectively. Furthermore, contact and vibrate responses of the rock sphere and the metal plate in the three types of the simulation are studied. The results show that the impact-contact response of the rock sphere obtained from the simulation that the elastic rock sphere impact on the elastic metal plate is more accurate. After the flexible treatment of the rock sphere and the metal plate, most of the system energy is consumed during the impact. The conclusions will provide a theoretical calculation method for the medium vertical reciprocating impact and a theoretical basis for the setting of the damping term in Adams simulation and support the research basis for the study of the impact behavior between coal gangue particles and the metal plate.