Analysis and Control of an Actuation-Redundant Parallel Mechanism Requiring Synchronization

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Fengfeng (Jeff) Xi ◽  
Amin Moosavian ◽  
Gabriel H. Campos ◽  
Upasana (Sana) Choudhuri ◽  
Cong Zhu (John) Sun ◽  
...  
Keyword(s):  
Parallel Mechanism ◽  
Closed Form Solution ◽  
Form Solution ◽  
Force Balance ◽  
End Effector ◽  
Velocity Relationship ◽  
Space Limitation ◽  
And Control ◽  
Force Profiles ◽  
Force Relationship

Abstract Presented in this paper is a method for analysis and control of an actuation-redundant parallel mechanism requiring synchronization. The said mechanism is made up of two branches that are connected to drive a common end-effector with only one degree-of-freedom of motion. The two actuators must share the load exerted on the common end-effector during motion. The underlying problem is to synchronize the motion of the two actuators while balancing the forces on them so that the entire mechanism can move smoothly under the applied load on the end-effector. Due to the space limitation, the two branches are geometrically different leading to opposite force profiles for the two actuators. The proposed method combines the mechanism kinematics with force analysis. First, a closed-form solution is derived that relates the actuator strokes to the rotation angle of the end-effector. Second, a velocity relationship is obtained to relate the actuator velocities to the angular velocity of the end-effector. Third, a force relationship is established relating the actuator loads to the external load. Fourth, a control strategy is designed to synchronize the motion of the two actuators while maintaining the force balance between them to avoid the problem of motion mismatching and force fighting that could lead to the failure of the mechanism. A prototype was built and tested with the proposed method, which is also presented in this paper.

DELEGATED MANAGEMENT IN DYNAMIC DUOPOLIES

2010 ◽  
Vol 12 (02) ◽  
pp. 93-114
Author(s):  
VLADIMIR P. PETKOV
Keyword(s):  
Functional Form ◽  
Closed Form Solution ◽  
Industry Structure ◽  
Form Solution ◽  
Linear Quadratic ◽  
Current Effort ◽  
First Mover Advantage ◽  
And Control ◽  
Direct Management ◽  
First Mover

This paper studies the commitment value of delegation in a model of dynamic competition. We argue that separating ownership and control delivers an instantaneous first-mover advantage. Thus, delegation would enable an oligopolistic firm to increase its equilibrium profit relative to direct management. We focus on remuneration strategies that provide managers with intertemporal production incentives: future wages depend on current effort. Their composition and functional form are endogenously determined by the requirement for Markov perfection. For the case of linear-quadratic payoffs, we obtain a closed-form solution for the equilibrium wage strategies which is independent of industry structure.

scholarly journals Mobility analysis of a robotic cardiopulmonary resuscitation device

2021 ◽  
Author(s):  
Mahdi Ardestani ◽  
Mohsen Asgari
Keyword(s):  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Closed Form Solution ◽  
Parallel Manipulators ◽  
Optimization Method ◽  
Form Solution ◽  
Mobility Analysis ◽  
Chest Compressions ◽  
Singularity Problem ◽  
Lower Mobility

Abstract During chest compressions action, in CPR (CPR), the 2 arms of the rescuer constitute a parallel mechanism. Inspired by this performance, during this study a specific family of lower mobility parallel manipulators by employing a modified version of Delta robot is proposed for chest compressions in rescuing a patient. One of the biggest differences between this mechanism and the Delta parallel mechanism is that the position of the three active connections of the robot relative to each other has changed the geometry of the platforms. Also, it shapes the asymmetrical structure within the robot mechanism and its workspace. Another difference is due to the architectural optimization method considering the mixed performance index, which has been used during this mechanism to achieve a much better compromise between the manipulator dexterity and its workspace. Within the present paper, after introducing the architecture of the robot, a closed-form solution is developed for the kinematic problem and therefore the results are verified using MSC. Adams©. Then Jacobian matrix is generated to gauge the singularity problem of the proposed mechanism. then, the workspace of the robot is investigated and compared with the original Delta mechanism.

Experimental Research on Force/Position Control of a Wire-Driven Parallel Rehabilitative Robot

2011 ◽  
Vol 138-139 ◽  
pp. 68-73 ◽  
Author(s):  
Ke Yi Wang ◽  
Fang Chao Ma ◽  
Meng Hao ◽  
Li Xun Zhang ◽  
Pan Liu
Keyword(s):  
Position Control ◽  
Parallel Robot ◽  
Force Balance ◽  
Robot System ◽  
End Effector ◽  
Wire Tension ◽  
Parallel Control ◽  
The Wire ◽  
And Control ◽  
Force Balance Equation

During rehabilitative training, a 3-DOF wire-driven parallel robot driven was designed to coordinate and control the trainer pelvis movement. Based on the force balance equation of the end-effector, the stiffness problem about the robot system was analyzed and one kind of force/position parallel control strategy was proposed that the position loop would realize the end-effector motion trajectory, and the force loop would control the wire tension. The experimental results have shown that the robot systematic stiffness is related with the wire tension and can be changed to realize the compliance control of the robot system by adjusting the wire tension.

Thermal Management Simulation of Lithium Ion Batteries for EV/HEV

2013 ◽  
Vol 457-458 ◽  
pp. 350-353
Author(s):  
Fofana Gaoussou Hadia ◽  
You Tong Zhang
Keyword(s):  
Lithium Ion Batteries ◽  
Heat Generation ◽  
Fundamental Problem ◽  
Three Dimensional ◽  
Closed Form Solution ◽  
Lithium Ion ◽  
Form Solution ◽  
Mechanism Analysis ◽  
And Control ◽  
The Impact

In this paper, we propose a three-dimensional analytical model based on Greens Function to investigate the Impact of temperature rising on simple lithium-ion batteries and control the heat generation during charge/discharge of battery operation. The modeling is based on heat-transform mechanism analysis method that gives a closed-form solution for the fundamental problem of heat conduction in battery cores with orthotropic thermal conductivities. The method uses a simple lithium-ion battery examined, considered the ambient temperature and initial temperature as 25°C, subjected to transient heat generation in various convective cooling boundary conditions at its surfaces.

scholarly journals ANALYTICAL EXPRESSION FOR UNCERTAINTY PROPAGATION OF AERIAL COOPERATIVE NAVIGATION

Aviation ◽  
2021 ◽  
Vol 25 (1) ◽  
pp. 10-21
Author(s):  
Ali Faghihinia ◽  
M. A. Amiri Atashgah ◽  
S. M. Mehdi Dehghan
Keyword(s):  
Growth Rate ◽  
Uncertainty Propagation ◽  
Closed Form Solution ◽  
Form Solution ◽  
Position Error ◽  
Measurement Unit ◽  
Propagation Of Uncertainty ◽  
Cooperative Navigation ◽  
Noise Characteristics ◽  
And Control

In this paper, the propagation of uncertainty in a cooperative navigation algorithm (CNA) for a group of flying robots (FRs) is investigated. Each FR is equipped with an inertial measurement unit (IMU) and range-bearing sensors to measure the relative distance and bearing angles between the agents. In this regard, an extended Kalman filter (EKF) is implemented to estimate the position and rotation angles of all the agents. For further studies, a relaxed analytical performance index through a closed-form solution is derived. Moreover, the effects of the sensors noise covariance and the number of FRs on the growth rate of the position error covariance is investigated. Analytically, it is shown that the covariance of position error in the vehicles equipped with the IMU is proportional to the cube of time. However, the growth rate of the navigation error is, considerably more rapid compared to a mobile robot group. Furthermore, the covariance of position error is independent of the path and noise resulting from the relative position measurements. Further, it merely depends on both the size of the group and noise characteristics of the accelerometers. Lastly, the analytical results are validated through comprehensive Guidance, Navigation, and Control (GNC) in-the-loop simulations.

scholarly journals A novel three degrees of freedom partially decoupled robot with linear actuators

Robotica ◽  
2011 ◽  
Vol 30 (3) ◽  
pp. 467-475 ◽  
Author(s):  
Jaime Gallardo-Alvarado ◽  
Gürsel Alici ◽  
Ramón Rodríguez-Castro
Keyword(s):  
Degrees Of Freedom ◽  
Control Point ◽  
Closed Form Solution ◽  
Parallel Manipulators ◽  
Form Solution ◽  
End Effector ◽  
Forward Displacement ◽  
Displacement Analysis ◽  
Common Control ◽  
Forward Displacement Analysis

SUMMARYIn this work, a new translational robot formed with two different parallel manipulators with a common control point is introduced. An asymmetric parallel manipulator provides three translational degrees of freedom to the proposed robot while the orientation of the end-effector platform is kept constant by means of a Delta-like manipulator. An exact solution is easily derived to solve the forward displacement analysis while a semi-closed form solution is available for solving the inverse displacement analysis. The infinitesimal kinematics of the robot is approached by applying the theory of screws. Finally, a numerical example that consists of solving the inverse/forward displacement analysis as well as the forward acceleration analysis of the end-effector platform is presented. The example also includes the computation of the workspace and the direct/inverse singularities of the example.

Negative Input Shaped Commands for Unequal Acceleration and Braking Delays of Actuators

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Yoon-Gyung Sung ◽  
Wan-Shik Jang ◽  
Jae-Yeol Kim
Keyword(s):  
Closed Form Solution ◽  
Industrial Applications ◽  
Step Function ◽  
Form Solution ◽  
Flexible Systems ◽  
Control Performance ◽  
Vector Diagram ◽  
Input Shaper ◽  
Benchmark System ◽  
And Control

A negative input shaped command is presented for flexible systems to reduce the residual oscillation under unequal acceleration and braking delays of actuators that are common issues in industrial applications. Against this nonlinearity, a compensated unit magnitude zero vibration (UMZV) shaper is analytically developed with a phasor vector diagram and a ramp-step function to approximate the dynamic response of the unequal acceleration and braking delays of actuators. A closed-form solution is presented with a benchmark system without sacrificing the generality and simplicity for industrial applications. The robustness and control performance of the exact solution are numerically evaluated and compared with those of an existing negative input shaper in terms of the switch-on time, command interference, and effects of the shaper parameters. The proposed negative input shaped commands are experimentally validated with a mini-bridge crane.

Weld Process Modeling, Monitoring, Teaching, and Control using Artificial Neural Networks: Improving Navy and Commercial Shipbuilding for the Future

2013 ◽  
Author(s):  
Jerald E. Jones ◽  
Valerie L. Rhoades ◽  
Mark D. Mann
Keyword(s):  
Neural Networks ◽  
Real Time ◽  
Closed Form Solution ◽  
Welding Process ◽  
Form Solution ◽  
Monitoring And Control ◽  
Element Analysis ◽  
Line Planning ◽  
Artificial Neural ◽  
And Control

Metal melting and solidification is a physical process which is described by a class of differential equations which have no closed form solution – it is known in Classical Mathematics as the “Stephan Problem”. The iterative methods used by numerical analyses techniques, such as Finite Element Analysis, are far too slow to be effective for process optimization and control. A DARPA Program a decade ago concentrated on flexible manufacturing – basically, robots that program themselves, depend heavily on sensors to be “smart” about their actions and decisions, and perform quality control with little, if any, human involvement. In the DARPA Flexible Automation program, a group of Ph.D. Scientists and Engineers, began applying a new Artificial Neural Network technology, called P/NA3. Today, Neural Networks produced using the P/NA3 technology are accurate and fast so that they can be run in real-time during welding or, embedded into specialized algorithms, to optimize the welding process. This technology enables the “off-line” planning of robotic welds, and real-time quality monitoring and control.

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