Impedance Control of Cable-Driven Mechanisms

2008 ◽  
Author(s):  
Siavash Rezazadeh ◽  
Saeed Behzadipour
Keyword(s):  
Force Feedback ◽  
Control Method ◽  
Impedance Control ◽  
Tensile Force ◽  
Classical Problem ◽  
The Body ◽  
Control Input ◽  
Body Parts ◽  
Lagrange’S Equation ◽  
Cable Forces

In this work, an impedance control method is developed and applied to two cable-driven mechanisms. The first one is a classical problem of driving a rigid body in 3-D space by seven cables. Our approach is based on the impedance control of rigid link manipulators which is then extended to include the specific considerations of the cable-driven mechanisms such as maintaining the tensile force in the cables. The method is then extended to the serial multibody cable-driven mechanisms. The motivation for this problem is the possible application of cable-driven systems in the rehabilitative exercises such as physical and/or occupational therapies. In this case, the human body acts as a multibody system which is driven by cables attached. The impedance control in such application facilitates the comfort of the patient by providing the necessary compliance while moving the body parts. The formulation of the problem is developed using Lagrange’s equation and the control input (which is the cable forces) is calculated based on the position and/or force feedback from the multibody. Simulation results demonstrate the effectiveness of the presented method.

A Nonlinear Optimal Control Approach for the Vertical Take-off and Landing Aircraft

2021 ◽  
pp. 2150012
Author(s):  
G. Rigatos
Keyword(s):  
Optimal Control ◽  
Control Method ◽  
Nonlinear Optimal Control ◽  
The Body ◽  
Algebraic Riccati Equation ◽  
Control Input ◽  
Time Step ◽  
Control Approach ◽  
Vtol Aircraft ◽  
Optimal Control Approach

The paper proposes a nonlinear optimal control approach for the model of the vertical take-off and landing (VTOL) aircraft. This aerial drone receives as control input a directed thrust, as well as forces acting on its wing tips. The latter forces are not perpendicular to the body axis of the drone but are tilted by a small angle. The dynamic model of the VTOL undergoes approximate linearization with the use of Taylor series expansion around a temporary operating point which is recomputed at each iteration of the control method. For the approximately linearized model, an H-infinity feedback controller is designed. The linearization procedure relies on the computation of the Jacobian matrices of the state-space model of the VTOL aircraft. The proposed control method stands for the solution of the optimal control problem for the nonlinear and multivariable dynamics of the aerial drone, under model uncertainties and external perturbations. For the computation of the controller’s feedback gains, an algebraic Riccati equation is solved at each time-step of the control method. The new nonlinear optimal control approach achieves fast and accurate tracking for all state variables of the VTOL aircraft, under moderate variations of the control inputs. The stability properties of the control scheme are proven through Lyapunov analysis.

Impedance control of a cable-driven SEA with mixed H2/H∞ synthesis

2017 ◽  
Vol 37 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Ningbo Yu ◽  
Wulin Zou
Keyword(s):  
Control Strategy ◽  
Control Method ◽  
Impedance Control ◽  
Low Frequency ◽  
Human Robot Interaction ◽  
Control Input ◽  
Robot Interaction ◽  
Content Type ◽  
Series Elastic Actuator ◽  
Series Elastic

Purpose This paper aims to present an impedance control method with mixed H2/H∞ synthesis and relaxed passivity for a cable-driven series elastic actuator to be applied for physical human–robot interaction. Design/methodology/approach To shape the system’s impedance to match a desired dynamic model, the impedance control problem was reformulated into an impedance matching structure. The desired competing performance requirements as well as constraints from the physical system can be characterized with weighting functions for respective signals. Considering the frequency properties of human movements, the passivity constraint for stable human–robot interaction, which is required on the entire frequency spectrum and may bring conservative solutions, has been relaxed in such a way that it only restrains the low frequency band. Thus, impedance control became a mixed H2/H∞ synthesis problem, and a dynamic output feedback controller can be obtained. Findings The proposed impedance control strategy has been tested for various desired impedance with both simulation and experiments on the cable-driven series elastic actuator platform. The actual interaction torque tracked well the desired torque within the desired norm bounds, and the control input was regulated below the motor velocity limit. The closed loop system can guarantee relaxed passivity at low frequency. Both simulation and experimental results have validated the feasibility and efficacy of the proposed method. Originality/value This impedance control strategy with mixed H2/H∞ synthesis and relaxed passivity provides a novel, effective and less conservative method for physical human–robot interaction control.

Switched-Impedance Control of Surgical Robots in Teleoperated Beating-Heart Surgery

2018 ◽  
Vol 03 (03n04) ◽  
pp. 1841003 ◽  
Author(s):  
Lingbo Cheng ◽  
Mahdi Tavakoli
Keyword(s):  
Heart Surgery ◽  
Force Feedback ◽  
Haptic Feedback ◽  
Control Method ◽  
Impedance Control ◽  
Beating Heart ◽  
Human Operator ◽  
Beating Heart Surgery ◽  
Impedance Models ◽  
Fast Motions

A novel switched-impedance control method is proposed and implemented for telerobotic beating-heart surgery. Differing from cardiopulmonary-bypass-based arrested-heart surgery, beating-heart surgery creates challenges for the human operator (surgeon) due to the heart’s fast motions and, in the case of a teleoperated surgical robot, the oscillatory haptic feedback to the operator. This paper designs two switched reference impedance models for the master and slave robots to achieve both motion compensation and nonoscillatory force feedback during slave–heart interaction. By changing the parameters of the impedance models, different performances for both robots are obtained: (a) when the slave robot does not make contact with the beating heart, the slave robot closely follows the motion of the master robot as in a regular teleoperation system, (b) when contact occurs, the slave robot automatically compensates for the fast motions of the beating heart while the human operator perceives the nonoscillatory component of the slave–heart interaction forces, creating the feeling of making contact with an idle heart for the human operator. The proposed method is validated through simulations and experiments.

Active Vibration Isolation for A Parallel Wheel-legged Robot Based on Dynamic Model

2020 ◽  
Author(s):  
Fei Guo ◽  
Shoukun Wang ◽  
Binkai Yue ◽  
Junzheng Wang
Keyword(s):  
Dynamic Model ◽  
Vibration Isolation ◽  
Force Feedback ◽  
Impedance Control ◽  
Inverse Kinematic ◽  
Control Input ◽  
Control Approach ◽  
Active Vibration ◽  
Robot Body ◽  
Active Vibration Isolation

Abstract Serving Stewart plat as wheel-legged construction, the most outstanding superiority of proposed wheel-legged hybrid robot (WLHR) is active vibration isolation during rolling on rugged terrain. This paper presents a force-driven control approach based on model predictive control (MPC) to design optimal control input for Stewart parallel wheel-leg that locomotes using swing foot trajectory. Adding adaptive impedance control in outermost loop, controlling framework prevents robot body horizontal and from vibration over rolling motion. Through dynamic model of Stewart mechanism, controller first creates predictive model by combining Newton-Euler equation, Newton-Raphson iteration of forward kinematic solving for current configuration, inverse kinematic calculation of Stewart obtaining desired joint position, and Gain/Integration module determining reference torque. With minimizing control deviation and input as objective function, a novel control optimization formulation generates optimum input for each control duration. These actuating force naturally enables each strut stretching and retracting used to realize six degree-of-freedom (6DOF) motion for Stewart wheel-leg. We exploit the variable-adapting method to reasonably adjust environmental impedance parameters by current position, velocity, force feedback of wheel-leg. This allow us to adequately acknowledge the desired support force tracking, isolating robot from isolation that is generated from unknown terrain. We demonstrate the validation of our control methodology on physical prototype by tracking a Bezier curve and active vibration isolation while the robot is rolling on decelerate strip. Respectively given PI controller and a sort of traditional impedance controller as comparison, a better performance of proposed algorithm was operated and evaluated through displacement and force sensors internally-installed in each cylinder, as well as IMU mounted on robot body.

Studies on Bilateral Impedance Control Method for Teleoperation Robot

2014 ◽  
Vol 602-605 ◽  
pp. 924-927
Author(s):  
Min Ying ◽  
Xin Gao ◽  
Si Yu Han ◽  
Han Xu Sun ◽  
Qing Xuan Jia
Keyword(s):  
Stability Condition ◽  
Stability Criterion ◽  
Absolute Stability ◽  
Force Feedback ◽  
Control Method ◽  
Impedance Control ◽  
Tracking Performance ◽  
System Stability ◽  
Pd Control ◽  
The Stability

The bilateral PD control method for teleoperation robot has some defects, such as poor tracking performance and force feedback performance. This paper, based on traditional bilateral PD control method, adds an impedance controller to the master and the slave, and deduces the stability condition according to the absolute stability criterion. The simulation shows that this method can assure the system stability and improve tracking performance and force feedback performance.

scholarly journals Design and Impedance Control of a Traveling Wave Ultrasonic Motor with a Spherical Rotor

2019 ◽  
Vol 9 (23) ◽  
pp. 5083
Author(s):  
Yu Guo ◽  
Aiguo Song ◽  
Zhijun Sun
Keyword(s):  
Phase Difference ◽  
Traveling Wave ◽  
Force Feedback ◽  
Control Method ◽  
Impedance Control ◽  
Direct Torque Control ◽  
Ultrasonic Motor ◽  
Torque Control ◽  
Haptic Interaction ◽  
Control Effect

A traveling wave ultrasonic motor (TWUM) with a spherical rotor was designed and fabricated for a haptic interface. The mechanical characteristics testbed was set up to test the performance of the motor under the modulation of frequency and phase difference, as well as for conducting haptic interaction, and the phase difference modulation based on certain frequency was adopted as the driving mode for the proposed motor. Due to the complexity and uncertainty of the contact mechanics of the stator and rotor, the direct torque control effect of the TWUM is not ideal for the force feedback. In this paper, the impedance control method was adopted to realize the force interaction based on positional proportional–integral–derivative (PID) control. The virtual linear spring and virtual wall experiments are conducted to verify the effect of the proposed method. Results show that the position-based impedance control method has a better effect than direct torque control for the haptic interaction based on an ultrasonic motor (USM).

Chattering-free sliding modes in robotic manipulators control

Robotica ◽  
1996 ◽  
Vol 14 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Asif Šabanović ◽  
Karel Jezernik ◽  
Kenzo Wada
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Sliding Mode ◽  
Impedance Control ◽  
Robotic Manipulators ◽  
Explicit Calculation ◽  
Control Input ◽  
Mathematical Form ◽  
Sliding Modes ◽  
Variable Structure Systems

SummaryIn this paper sliding mode motion design is considered for nonlinear plants which are linear with respect to control input. The dynamics of the robotic manipulators is treated with and without those of the actuators. When the dynamics of the actuators is included a design of the sliding modes for the systems with discontinuous control is performed. If actuators' dynamics is negelected the control is assumed to be continuous quantity. By combining the variable structure systems and Lyapunov designs a new algorithm is developed which has all the good properties of the sliding mode systems while avoiding unnecessary discontinuity of the control thus eliminating chattering. Neither the explicit calculation of the equivalent control, nor high gain inside the boundary layer are used. The parameters of the control depend on the plant's gain matrix, and the gradients of the sliding mode manifold. This control method is then applied to develop a unified control strategy for the motion control systems including the path tracking control, the impedance control and the force control of a robotic manipulator. It is shown that all these tasks can be formulated in the same mathematical form in which selected so-called sliding mode functions must track their references. In this way the systems state is forced to remain on the selected manifold in the state space after reaching it. The solution is interpreted in both the Joint space and the Work space for n -degrees of freedom robotic manipulators.

Formulation, Design and Development of Niosome Based Topical Gel for Skin Cancer

2017 ◽  
Vol 2 (3) ◽  
Keyword(s):  
Skin Cancer ◽  
Drug Release ◽  
Hemorrhagic Cystitis ◽  
The Body ◽  
Cancer Drug ◽  
Inversion Method ◽  
Body Parts ◽  
Basal Cells ◽  
Formulation Design ◽  
Topical Gel

Melanoma is the most dangerous type of skin cancer in which mostly damaged unpaired DNA starts mutating abnormally and staged an unprecedented proliferation of epithelial skin to form a malignant tumor. In epidemics of skin, pigment-forming melanocytes of basal cells start depleting and form uneven black or brown moles. Melanoma can further spread all over the body parts and could become hard to detect. In USA Melanoma kills an estimated 10,130 people annually. This challenge can be succumbed by using the certain anti-cancer drug. In this study design, cyclophosphamide were used as a model drug. But it has own limitation like mild to moderate use may cause severe cytopenia, hemorrhagic cystitis, neutropenia, alopecia and GI disturbance. This is a promising challenge, which is caused due to the increasing in plasma drug concentration above therapeutic level and due to no rate limiting steps involved in formulation design. In this study, we tried to modify drug release up to threefold and extended the release of drug by preparing and designing niosome based topical gel. In the presence of Dichloromethane, Span60 and cholesterol, the initial niosomes were prepared using vacuum evaporator. The optimum percentage drug entrapment efficacy, zeta potential, particle size was found to be 72.16%, 6.19mV, 1.67µm.Prepared niosomes were further characterized using TEM analyzer. The optimum batch of niosomes was selected and incorporated into topical gel preparation. Cold inversion method and Poloxamer -188 and HPMC as core polymers, were used to prepare cyclophosphamide niosome based topical gel. The formula was designed using Design expert 7.0.0 software and Box-Behnken Design model was selected. Almost all the evaluation parameters were studied and reported. The MTT shows good % cell growth inhibition by prepared niosome based gel against of A375 cell line. The drug release was extended up to 20th hours. Further as per ICH Q1A (R2), guideline 6 month stability studies were performed. The results were satisfactory and indicating a good formulation approach design was achieved for Melanoma treatment.

Re-imagining Reproduction: Unsettling Metaphors in the History of Imperial Science and Commercial Surrogacy in India

Somatechnics ◽  
2015 ◽  
Vol 5 (1) ◽  
pp. 88-103 ◽  
Author(s):  
Kalindi Vora
Keyword(s):  
Assisted Reproductive Technologies ◽  
Reproductive Technologies ◽  
The Body ◽  
Body Parts ◽  
Colonial History ◽  
Women's Bodies ◽  
Commercial Surrogacy ◽  
Art Practices ◽  
History Of ◽  
Travel Industry

This paper provides an analysis of how cultural notions of the body and kinship conveyed through Western medical technologies and practices in Assisted Reproductive Technologies (ART) bring together India's colonial history and its economic development through outsourcing, globalisation and instrumentalised notions of the reproductive body in transnational commercial surrogacy. Essential to this industry is the concept of the disembodied uterus that has arisen in scientific and medical practice, which allows for the logic of the ‘gestational carrier’ as a functional role in ART practices, and therefore in transnational medical fertility travel to India. Highlighting the instrumentalisation of the uterus as an alienable component of a body and subject – and therefore of women's bodies in surrogacy – helps elucidate some of the material and political stakes that accompany the growth of the fertility travel industry in India, where histories of privilege and difference converge. I conclude that the metaphors we use to structure our understanding of bodies and body parts impact how we imagine appropriate roles for people and their bodies in ways that are still deeply entangled with imperial histories of science, and these histories shape the contemporary disparities found in access to medical and legal protections among participants in transnational surrogacy arrangements.

Deadlift Recognition and Application based on Multiple Modalities using Recurrent Neural Network

2020 ◽  
Vol 2020 (17) ◽  
pp. 2-1-2-6
Author(s):  
Shih-Wei Sun ◽  
Ting-Chen Mou ◽  
Pao-Chi Chang
Keyword(s):  
Neural Network ◽  
Recurrent Neural Network ◽  
Network Structure ◽  
Inertial Sensors ◽  
Body Movement ◽  
The Body ◽  
Body Parts ◽  
Multimodal Sensing ◽  
Multiple Devices ◽  
Neural Network Structure

To improve the workout efficiency and to provide the body movement suggestions to users in a “smart gym” environment, we propose to use a depth camera for capturing a user’s body parts and mount multiple inertial sensors on the body parts of a user to generate deadlift behavior models generated by a recurrent neural network structure. The contribution of this paper is trifold: 1) The multimodal sensing signals obtained from multiple devices are fused for generating the deadlift behavior classifiers, 2) the recurrent neural network structure can analyze the information from the synchronized skeletal and inertial sensing data, and 3) a Vaplab dataset is generated for evaluating the deadlift behaviors recognizing capability in the proposed method.

Sign in / Sign up

Export Citation Format

Share Document