Design, Development, and Analysis of a Hemispherical Singularity Drive System for Instantaneously Omnidirectional Motion With Kinematic Isotropy

2016 ◽  
Author(s):  
Elliott Clarke ◽  
Bryan Fite ◽  
Julie A. Reyer
Keyword(s):  
Inverse Kinematics ◽  
Wheel Speed ◽  
Drive System ◽  
Neutral Position ◽  
Design Development ◽  
Governing Equations ◽  
Thrust Vector ◽  
Singularity Point ◽  
Wheel Radius ◽  
Singularity Drive System

This paper presents an omnidirectional drive system with instantaneous omnidirectionality and kinematic isotropy, the Hemispherical Singularity Drive (HSD). By driving a hemispherical wheel mounted on a pointing mechanism, a thrust vector can be generated with arbitrary direction and magnitude. The direction of this thrust is determined by the pointing mechanism’s heading and the magnitude is a function of wheel speed and effective wheel radius, which is in turn dictated by the degree of wheel tilt. At “neutral” position, the wheel operates at its singularity point, producing no thrust regardless of wheel speed. This paper presents the design, kinematics, and an approach to the inverse kinematics of a single module. An omnidirectional robot can have one or more of these modules, effecting increased degrees of mobility, and the governing equations for control of a robot with three or more modules are presented.

An Omnidirectional, Direct Singularity Drive System and its Inverse Kinematic Model

2014 ◽  
Author(s):  
Julie A. Reyer ◽  
Matthew T. West ◽  
Praveen K. Jonnavittula ◽  
Christopher T. Costello ◽  
Curtis Boirum
Keyword(s):  
Inverse Kinematics ◽  
Kinematic Model ◽  
Inverse Kinematic ◽  
Effective Radius ◽  
Drive System ◽  
Experimental Results ◽  
Kinematics Analysis ◽  
Thrust Vector ◽  
Singularity Point ◽  
Singularity Drive System

This paper presents an omnidirectional drive system. The design presented here involves a spinning hemispherical wheel mounted on a gimbal. The wheel operates at its singularity point when in the “neutral” or static position. As the gimbal is tilted, the wheel provides a thrust vector to the vehicle. The tilt determines the effective radius of the wheel, which in turn determines the amount of power that can be transmitted for motion. The paper presents the design and kinematic and inverse kinematics analysis of a singularity drive mechanism. Vehicles can have single or multiple singularity drive mechanisms to achieve increasing levels of maneuverability. From a control standpoint, each singularity drive is kinematically decoupled from other drives on the same vehicle. Vehicles with one, two and three singularity drive mechanisms are introduced and some experimental results are presented.

Kinematics and Dynamics of a Parallel Manipulator With Woven Joints

1993 ◽  
Author(s):  
Hyunsok Pang
Keyword(s):  
Lagrange Multipliers ◽  
Kinematic Analysis ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Inverse Dynamics ◽  
Numerical Technique ◽  
Vector Analysis ◽  
Kinematics And Dynamics ◽  
Governing Equations ◽  
Numerical Examples

Abstract Presented is an analysis of the kinematics and the inverse dynamics of a proposed three DOF parallel manipulator resembling the Stewart platform in a general form. In the kinematic analysis, the inverse kinematics, velocity and acceleration analyses are performed, respectively, using vector analysis and general homogeneous transformations. An algorithm to solve the inverse dynamics of the proposed parallel manipulator is then presented using a Lagrangin technique. In this case, it is found that one should introduce and subsequently eliminate Lagrange multipliers in order to arrive at the governing equations. Numerical examples are finally carried out to examine the validity of the approach and the accuracy of the numerical technique employed. The trajectory of motion of the manipulator is also performed using a cubic spline.

Under Pressure Compensation for Wheel Radius Based on Wheel Speed

2014 ◽  
Vol 602-605 ◽  
pp. 438-442
Author(s):  
Hui En Gao ◽  
Liang Chu ◽  
Jian Chen ◽  
Wen Hui Li
Keyword(s):  
High Speed ◽  
Rolling Resistance ◽  
Wheel Speed ◽  
Braking System ◽  
Control Robustness ◽  
Tire Wear ◽  
Pressure Compensation ◽  
Wheel Radius ◽  
Additional Fuel Consumption ◽  
Additional Fuel

Tire under-pressure will increase vehicle’s rolling resistance, additional fuel consumption and possibility of tire wear, which will magnify the possibility of a flat tire when vehicle drives at a high speed. In addition, an under-pressure tire will cause a smaller wheel radius, which influences wheel speed calculation in Anti-lock Braking System (ABS) and reduces the control robustness. In this paper, an under pressure compensation algorithm for wheel radius based on ABS wheel speed is proposed, which can improve the accuracy of ABS control and indirectly give early warning of a single under-pressure tire as well. Finally it has been validated by vehicle experiments.

Inverse Kinematics and Geometric Relations of an Intelligent Modified Stewart Platform for Thrust Vector Control

Aerospace ◽  
2004 ◽  
Author(s):  
Mehrdad N. Ghasemi Nejhad
Keyword(s):  
Vector Control ◽  
Inverse Kinematics ◽  
Vibration Suppression ◽  
Intelligent System ◽  
Research Effort ◽  
Stewart Platform ◽  
Fine Tuning ◽  
Precision Positioning ◽  
Thrust Vector Control ◽  
Thrust Vector

Adaptive or intelligent structures which have the capability for sensing and responding to their environment promise a novel approach to satisfying the stringent performance requirements of future space missions. This research effort focuses on the development of an intelligent thruster mount structure with precision positioning and active vibration suppression capability for use in a space satellite. The intelligent thruster mount would utilize piezoelectric stacks and patches for precision positioning and vibration suppression to provide fine-tuning of position tolerance for thruster alignment and low transmissibility of vibration to the satellite structure. This vibration, if not suppressed, renders sensitive optical or measurement equipment non-operational until the disturbance has dissipated. This intelligent system approach would greatly enhance mission performance by fine tuning attitude control, potentially eliminating the non-operational period as well as minimizing fuel consumption utilized for position correction. The configuration of the intelligent thruster mount system is that of a modified Stewart platform. Precision positioning of this structure is achieved using active composite strut members that use piezoelectric stack actuators and extend or contract to tilt the top device-plate where the thruster is mounted. The geometric relationship between the Stewart platform and the modified Stewart platform is described, and an inverse kinematics analysis of the modified Stewart platform has been developed and is used to determine the required axial displacement of the active struts for the desired angular tilt of the top device-plate. The active struts can participate in precision positioning as well as vibration suppression of the top device-plate where the thruster, i.e., the source of the unwanted vibrations and misalignment, is mounted. The proposed Thrust Vector Control (TVC) intelligent platform offers a promising method for achieving fine tuning of positioning tolerances of a thruster as well as minimizing the effects of the disturbances generated during thruster firing in spacecraft such as a satellite.

Optimization-based trajectory planning of the human upper body

Robotica ◽  
2006 ◽  
Vol 24 (6) ◽  
pp. 683-696 ◽  
Author(s):  
Karim Abdel-Malek ◽  
Zan Mi ◽  
Jingzhou Yang ◽  
Kyle Nebel
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Optimization Technique ◽  
Displacement Function ◽  
Upper Body ◽  
Target Point ◽  
Optimization Approach ◽  
Neutral Position ◽  
Direct Optimization ◽  
Set Up

This paper presents studies of the coordination of human upper body voluntary movement. A minimum-jerk 3D model is used to obtain the desired path in Cartesian space, which is widely used in the prediction of human reach movement. Instead of inverse kinematics, a direct optimization approach is used to predict each joint's profile (a spline curve). This optimization problem has four cost function terms: (1) Joint displacement function that evaluates displacement of each joint away from its neutral position; (2) Inconsistency function, which is the joint rate change (first derivative) and predicted overall trend from the initial target point to the final target point; (3) The non-smoothness function of the trajectory, which is the second derivative of the joint trajectory; (4) The non-continuity function, which consists of the amplitudes of joint angle rates at the initial and final target points, in order to emphasize smooth starting and ending conditions. This direct optimization technique can be used for potentially any number of degrees of freedom (DOF) system and it reduces the cost associated with certain inverse kinematics approaches for resolving joint profiles. This paper presents a high redundant upper-body modeling with 15 DOFs. Illustrative examples are presented and an interface is set up to visualize the results.

scholarly journals The inverse kinematics analysis and simulation study on the controllable loading mechanism

2018 ◽  
Vol 189 ◽  
pp. 06011
Author(s):  
Lin Zhang ◽  
Cheng-ge Wu ◽  
Gan-wei Cai
Keyword(s):  
Inverse Kinematics ◽  
Hydraulic Drive ◽  
Transmission Efficiency ◽  
Drive System ◽  
Vector Method ◽  
Kinematics Model ◽  
Electric Drive System ◽  
New Type ◽  
Input Motion ◽  
Further Development

The multi-DOF controllable loading mechanism adopts the electric drive system to replace the hydraulic drive system of traditional loader, not only has higher transmission efficiency and has better mechanical and electrical integration level, but also overcome the shortcomings of high cost of manufacture and maintenance.The inverse kinematics model of this type of loading mechanism was built by means of closed loop vector method. According to the performance index of the loading mechanism, the inverse kinematics model was solved by means of MATLAB software, and the input motion law of the two driving lever at different period of time is obtained, and a small prototype is built, which provides the basis for control system programming of this new type of leading mechanism. To some extent, this research lays a foundation for further development of this type of loading mechanism.

Model predictive control based on time-varying efficiency for hydraulic hub-motor driving vehicle

2021 ◽  
pp. 095440702110058
Author(s):  
Xiaohua Zeng ◽  
Liangyu Li ◽  
Dafeng Song ◽  
Lixin Li ◽  
Guanghan Li
Keyword(s):  
Feedback Control ◽  
Model Predictive Control ◽  
Predictive Control ◽  
Control Method ◽  
Hydraulic Drive ◽  
Wheel Speed ◽  
Drive System ◽  
Time Varying ◽  
Target Displacement ◽  
Speed Difference

A model predictive feedback control strategy based on time-varying efficiency is investigated and applied to a hydraulic hub-motor auxiliary system (HHMAS) in this paper. Adding HHMAS to a traditional heavy commercial vehicle can improve fuel economy and traction performance on roads with low adhesion coefficients. However, the hydraulic drive system experiences serious disturbance imposed by time-varying parameters and external conditions. Model predictive feedback control based on time-varying efficiency offers a solution for HHMAS to cope with the disadvantage of the hydraulic drive system and improve the environmental adaptability of the vehicle controller. In this study, the control law of hydraulic variable pump (HVP) target displacement is established based on temperature compensation in consideration of the influence of multiple factors on pump target displacement. For coordinated power distribution of HHMAS, the minimum wheel speed difference and the reduction in system impact are regarded as optimal control targets in adjusting the engine torque and HVP displacement and designing the model predictive controller. Simulation results show that the proposed model predictive control method can reduce the speed difference between front and rear wheels by up to 64% and can achieve the wheel speed following effect faster than the traditional proportional-integral-derivative algorithm. Given that the control parameters do not need to be calibrated in the proposed method, the calibration time is saved, and the actual development process of the hydraulic hub-motor driving vehicle is remarkably improved.

PENGEMBANGAN BAHAN AJAR PROBLEM BASED LEARNING KEMAMPUAN PEMECAHAN MASALAH MATERI SPLTV

2019 ◽  
Vol 3 (1) ◽  
pp. 70-80
Author(s):  
Sri Ayu Harani Tanjung ◽  
Yuli Amalia
Keyword(s):  
Problem Solving ◽  
Mathematical Problem ◽  
Problem Based Learning ◽  
Student Response ◽  
Design Development ◽  
Research Subjects ◽  
Teaching Materials ◽  
Problem Solving Skills ◽  
Ability Tests ◽  
Analysis Design

Bahan ajar dikembangkan berdasarkan karakteristik siswa, sehingga kompetensi yang ditetapkan dapat dicapai. Secara umum kemampuan pemecahan masalah siswa masih sangat rendah, siswa belum bisa memahami soal, sehingga terkendala dalam menentukan model penyelesaian soal matematika. Penelitian ini bertujuan untuk mendeskripsikan kevalidan, keefektifan, dan respon siswa terhadap bahan ajar berbasis Problem Based Learning berkemampuan pemecahan masalah yang dikembangkan. Penelitian ini merupakan penelitian pengembangan dengan menggunakan model ADDIE yaitu Analysis, Design, Development, Implementation, dan Evaluation. Subjek Penelitan dalam penelitian ini adalah siswa SMA Negeri 1 Meureubo kelas X Mia2 sebanyak 23 siswa. Instrumen penelitian berupa lembar validasi, angket respon siswa, dan tes. Dari hasil uji coba, pada uji coba I dan II diperoleh bahan ajar berbasis Problem Based Learning yang dikembangkan efektif ditinjau dari 70% siswa yang mengikuti tes kemampuan pemecahan masalah memperoleh nilai minimal 75 dan tercapainya ketuntasan belajar tes kemampuan pemecahan masalah  75% dan respon positif siswa terhadap bahan ajar berbasis Problem Based Learning untuk kemampuan pemecahan masalah yang dikembangkan. Teaching materials are developed based on the characteristics of students, so that the specified competencies can be achieved. In general, students' problem solving abilities are still very low, students have not been able to understand the problem, so it is constrained in determining the mathematical problem solving model. This study aims to describe the validity, effectiveness, and response of students to Problem Based Learning-based teaching materials that are problem-solving skills developed. This research is a development research using ADDIE models namely Analysis, Design, Development, Implementation, and Evaluation. The research subjects in this study were 23 students of Meureubo High School 1 in class Mia2 as many as 23 students. The research instruments were validation sheets, student response questionnaires, and tests. From the results of the trials, in the first and second trials obtained teaching materials based on Problem Based Learning that were developed effectively in terms of 70% of students taking the test of problem solving skills obtained a minimum score of 75 and achievement of learning completeness 75% problem solving ability tests and positive responses for Problem Based Learning based teaching materials for problem solving abilities developed.

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