Modeling and Control of a Novel Variable-Stiffness Regenerative Actuator

2018 ◽  
Author(s):  
Erivelton Gualter dos Santos ◽  
Hanz Richter
Keyword(s):  
Position Control ◽  
Lightweight Design ◽  
Variable Stiffness ◽  
Electrical Energy ◽  
Flexible Beam ◽  
Modeling And Control ◽  
Electromechanical Drive ◽  
Elastic Potential Energy ◽  
Mechanical Dynamics ◽  
And Control

This paper focuses on the design, modeling and basic control of a variable stiffness actuator to be used in combination with a regenerative electromechanical drive system. Due to the use of a flexible beam, the actuator has the ability to store and return elastic potential energy. Also, an ultracapacitor is used in the electromechanical drive, which allows electrical energy storage and return. Moreover, elastic and electrostatic energies can be exchanged, resulting in a highly efficient and lightweight design which will be beneficial for robotic prostheses, exoskeletons and other orthotic devices. The paper presents a model and calculation method for large beam deflections and the integrated electromechanical actuator model. A semiactive virtual control strategy is used to decouple the mechanical dynamics from the charge dynamics and achieve position control of the actuator. Simulation results are presented to illustrate the control system and the energy exchange features.

scholarly journals Dynamic Modeling and Control of Antagonistic Variable Stiffness Joint Actuator

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 116
Author(s):  
Ming Zhang ◽  
Pengfei Ma ◽  
Feng Sun ◽  
Xingwei Sun ◽  
Fangchao Xu ◽  
...  
Keyword(s):  
Dynamic Modeling ◽  
Position Control ◽  
Jacobian Matrix ◽  
Control Method ◽  
Variable Stiffness ◽  
Compliance Control ◽  
Decoupling Method ◽  
Modeling And Control ◽  
And Control ◽  
Variable Stiffness Actuators

This study aims to develop a novel decoupling method for the independent control of the position and stiffness of a variable stiffness joint actuator (VSJA), which has been proven to be able to vary its stiffness in a larger range than other variable stiffness actuators. Using static analysis and the Jacobian matrix, we obtained the model of the stiffness of the robot joint actuator and dynamics. Based on the hybrid dynamic model of position and stiffness, it is possible to compensate for the torque of the variable stiffness joint actuator (VSJA) to enhance position control. Finally, after describing the actuator prototype, the established compliance control method is verified using simulation and experimental analysis.

scholarly journals A Riemannian-Geometry Approach for Modeling and Control of Dynamics of Object Manipulation under Constraints

2009 ◽  
Vol 2009 ◽  
pp. 1-16 ◽  
Author(s):  
Suguru Arimoto ◽  
Morio Yoshida ◽  
Masahiro Sekimoto ◽  
Kenji Tahara
Keyword(s):  
Riemannian Geometry ◽  
Position Control ◽  
Hybrid Control ◽  
Object Manipulation ◽  
Rolling Contact ◽  
Kernel Space ◽  
Constraint Forces ◽  
Modeling And Control ◽  
Holonomic Constraints ◽  
And Control

A Riemannian-geometry approach for modeling and control of dynamics of object manipulation under holonomic or non-holonomic constraints is presented. First, position/force hybrid control of an endeffector of a multijoint redundant (or nonredundant) robot under a holonomic constraint is reinterpreted in terms of “submersion” in Riemannian geometry. A force control signal constructed in the image space of the constraint gradient is regarded as a lifting (or pressing) in the direction orthogonal to the kernel space. By means of the Riemannian distance on the constraint submanifold, stability of position control under holonomic constraints is discussed. Second, modeling and control of two-dimensional object grasping by a pair of multijoint robot fingers are challenged, when the object is of arbitrary shape. It is shown that rolling contact constraints induce the Euler equation of motion, in which constraint forces appear as wrench vectors affecting the object. The Riemannian metric is introduced on a constraint submanifold characterized with arclength parameters. An explicit form of the quotient dynamics is expressed in the kernel space with accompaniment of a pair of first-order differential equations concerning the arclength parameters. An extension of Dirichlet-Lagrange's stability theorem to redundant systems under constraints is suggested by introducing a Morse-Lyapunov function.

scholarly journals Modeling and control of an IPMC actuated flexible beam under the port-Hamiltonian framework

2019 ◽  
Vol 52 (2) ◽  
pp. 108-113
Author(s):  
Yongxin Wu ◽  
François Lamoline ◽  
Joseph Winkin ◽  
Yann Le Gorrec
Keyword(s):  
Flexible Beam ◽  
Modeling And Control ◽  
And Control

Modeling and Control of Manufacturing Processes: Getting More Involved

1993 ◽  
Vol 115 (2B) ◽  
pp. 291-300 ◽  
Author(s):  
David E. Hardt
Keyword(s):  
Position Control ◽  
Transformation Process ◽  
Actual Process ◽  
Modeling And Control ◽  
Control Techniques ◽  
Specific Geometry ◽  
Process Output ◽  
Internal Properties ◽  
And Control

The discipline of control has had numerous yet sporadic contacts with the manufacturing world over the past few decades, almost always as an afterthought or addendum, and typically in the role of machine and not as process control. Much of this detachment comes from an absence of control techniques that can deal directly with the actual manufacturing process, i.e., a material transformation process that produces a desired object both in terms of specific geometry and internal properties. Instead, most efforts have focused on using existing methods on process independent problems, such as position control and trajectory following, or on straightforward process parameter control, thereby only indirectly influencing the actual process output. This paper presents the reasons behind and the means to eliminate this estrangement, using the author’s own research as an example of a more direct approach to process modeling and control.

Design, modeling and control of a reconfigurable variable stiffness actuator

2021 ◽  
Vol 160 ◽  
pp. 107883
Author(s):  
Yapeng Xu ◽  
Kai Guo ◽  
Jie Sun ◽  
Jianfeng Li
Keyword(s):  
Variable Stiffness ◽  
Modeling And Control ◽  
Variable Stiffness Actuator ◽  
And Control

Design, Modeling, and Control of a Variable Stiffness Device for Wrist Rehabilitation

2021 ◽  
Author(s):  
O. Manolo Flores ◽  
Jesus H. Lugo ◽  
Alejandro Gonzalez ◽  
Mauro Maya ◽  
Emilio J. Gonzalez-Galvan ◽  
...  
Keyword(s):  
Variable Stiffness ◽  
Modeling And Control ◽  
And Control

Modeling and Control of Backlash in the Drive Mechanism of a Radially Rotating Compliant Beam

1996 ◽  
Vol 118 (1) ◽  
pp. 158-161 ◽  
Author(s):  
Nabil G. Chalhoub ◽  
Xiaoying Zhang
Keyword(s):  
Adverse Effects ◽  
Controller Design ◽  
System Response ◽  
Flexible Beam ◽  
Modeling And Control ◽  
Drive Mechanism ◽  
Servo Loop ◽  
Viable Approach ◽  
And Control ◽  
Digital Simulations

The exclusion of the dynamic characteristics of indirect drives, from the controller design, has often led to a degraded performance in precision servomechanisms. In this study, the adverse effects of backlash, in the drive mechanism of a radially rotating flexible beam, are examined. The topological variations of the structure are handled by latent constraint equations which can be rendered active through the monitoring of the contact torque as well as kinematic indicators. A “backlash controller” is introduced to replace the original controller of the beam only during the period of gear disengagement. The experimental and numerical results provide a qualitative validation of the backlash model. The relationships with which the backlash in gearing would interact with both the servo-loop controller and the structural flexibility of the system are investigated. In addition, the digital simulations have proven that the “backlash controller” provides a viable approach in reducing the adverse effects of backlash on the overall system response.

scholarly journals An efficient leg with series–parallel and biarticular compliant actuation: design optimization, modeling, and control of the eLeg

2019 ◽  
pp. 027836491989376
Author(s):  
Wesley Roozing ◽  
Zeyu Ren ◽  
Nikos G Tsagarakis
Keyword(s):  
State Of The Art ◽  
Control Strategies ◽  
Electrical Energy ◽  
Knee Joints ◽  
Design Parameters ◽  
Modeling And Control ◽  
Actuation Scheme ◽  
Three Degree Of Freedom ◽  
And Control ◽  
Series Elastic

We present the development, modeling, and control of a three-degree-of-freedom compliantly actuated leg called the eLeg, which employs both series- and parallel-elastic actuation as well as a bio-inspired biarticular tendon. The leg can be reconfigured to use three distinct actuation configurations, to directly compare with a state-of-the-art series-elastic actuation scheme. Critical actuation design parameters are derived through optimization. A rigorous modeling approach is presented using the concept of power flows, which are also used to demonstrate the ability to transfer mechanical power between ankle and knee joints using the biarticular tendon. The design principles and control strategies were verified both in simulation and experiment. Notably, the experimental data demonstrate significant improvements of 65–75% in electrical energy consumption compared with a state-of-the-art series-elastic actuator configuration.

Modeling and Control of Single-Link Flexible Arms With Lumped Masses

1992 ◽  
Vol 114 (1) ◽  
pp. 59-69 ◽  
Author(s):  
V. Feliu ◽  
K. S. Rattan ◽  
H. B. Brown
Keyword(s):  
Control Method ◽  
Flexible Beam ◽  
Outer Loop ◽  
Modeling And Control ◽  
Control Scheme ◽  
Single Link ◽  
Tip Position ◽  
Flexible Arms ◽  
Lumped Masses ◽  
And Control

This paper deals with the modeling and control of a special class of single-link flexible arms. These arms consist of flexible massless structures having some masses concentrated at certain points of the beam. In this paper, the dynamic model of such flexible arms is developed and some of the control properties are deduced. A robust control scheme to remove the effects of friction in the joins is proposed. The control scheme consists of two nested feedback loops, an inner loop to control the position of the motor and an outer loop to control the tip position. The inner loop is described in other publications. A simple feedforward-feedback controller is designed for the outer loop to drive the beam accurately along a desired trajectory. Effects of the changes in the tip’s mass are studied. This modeling and control method is then generalized to the distributed-mass flexible beam case. Finally, experimental results are presented.

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