scholarly journals Model-Based Control and External Load Estimation of an Extensible Soft Robotic Arm

2021 ◽  
Vol 7 ◽  
Author(s):  
Xiaojiao Chen ◽  
Dehao Duanmu ◽  
Zheng Wang
Keyword(s):  
External Load ◽  
Control Strategies ◽  
Estimation Error ◽  
Estimation Procedure ◽  
Robotic Arm ◽  
Soft Robotics ◽  
Level Control ◽  
Compliant Behavior ◽  
High Level ◽  
Soft Robotic Arm

Soft robotics has widely been known for its compliant characteristics when dealing with contraction or manipulation. These soft behavior patterns provide safe and adaptive interactions, greatly relieving the complexity of active control policies. However, another promising aspect of soft robotics, which is to achieve useful information from compliant behavior, is not widely studied. This characteristic could help to reduce the dependence of sensors, gain a better knowledge of the environment, and enrich high-level control strategies. In this paper, we have developed a state-change model of a soft robotic arm, and we demonstrate how compliant behavior could be used to estimate external load based on this model. Moreover, we propose an improved version of the estimation procedure, further reducing the estimation error by compensating the influcence of pressure deadzone. Experiments of both methods are compared, displaying the potential effectiveness of applying these methods.

Powered Ankle-Foot Prostheses: A Survey on Sensing Systems and Control Strategies

2019 ◽  
Author(s):  
Erik Chumacero-Polanco ◽  
James Yang
Keyword(s):  
Control Strategies ◽  
Level Control ◽  
Low Level ◽  
Kinetic Information ◽  
Sensing Systems ◽  
Systems And Control ◽  
Finite State ◽  
High Level ◽  
And Control

Abstract People who have suffered a transtibial amputation show diminished ambulation and impaired quality of life. Powered ankle foot prostheses (AFP) are used to recover some mobility of transtibial amputees (TTAs). Powered AFP is an emerging technology that has great potential to improve the quality of life of TTAs with important avenues for research and development in different fields. This paper presents a survey on sensing systems and control strategies applied to powered AFPs. Sensing kinematic and kinetic information in powered AFPs is critical for control. Ankle angle position is commonly obtained via potentiometers and encoders directly installed on the joint, velocities can be estimated using numerical differentiators, and accelerations are normally obtained via inertial measurement units (IMUs). On the other hand, kinetic information is usually obtained via strain gauges and torque sensors. On the other hand, control strategies are classified as high- and low-level control. The high-level control sets the torque or position references based on pattern generators, user’s intent of motion recognition, or finite-state machine. The low-level control usually consists of linear controllers that drive the ankle’s joint position, velocity, or torque to follow an imposed reference signal. The most widely used control strategy is the one based on finite-state machines for the high-level control combined with a proportional-derivative torque control for low-level. Most designs have been experimentally assessed with acceptable results in terms of walking speed. However, some drawbacks related to powered AFP’s weight and autonomy remain to be overcome. Future research should be focused on reducing powered AFP size and weight, increasing energy efficiency, and improving both the high- and the low-level controllers in terms of efficiency and performance.

scholarly journals Multi-Objective Supervisory Control for DC/DC Converters in Advanced Aeronautic Applications

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3216 ◽  
Author(s):  
Alberto Cavallo ◽  
Giacomo Canciello ◽  
Beniamino Guida ◽  
Ponggorn Kulsangcharoen ◽  
Seang Yeoh ◽  
...  
Keyword(s):  
Low Voltage ◽  
Control Strategies ◽  
Gain Control ◽  
High Gain ◽  
Level Control ◽  
Mathematical Arguments ◽  
Control Scheme ◽  
Sliding Manifold ◽  
High Gain Control ◽  
High Level

In this paper, an intelligent control strategy for DC/DC converters is proposed. The converter connects two DC busses, a high-voltage and a low-voltage bus. The control scheme is composed by a two-layer architecture, a low-level control based on the concept of sliding manifold, and high gain control, and a high-level control used to guarantee the achievement of various objectives. The proposed control strategies are based on solid mathematical arguments, with stability proofs for the non-linear case, and decision trees for parameter selection. The paper results are analyzed and discussed by using simulation at different detail levels in MATLAB/Stateflow/PowerSystem, and validated by experimental results, also considering MIL standard performance indices.

Control of a 7-DOF Robotic Arm System With an SSVEP-Based BCI

2018 ◽  
Vol 28 (08) ◽  
pp. 1850018 ◽  
Author(s):  
Xiaogang Chen ◽  
Bing Zhao ◽  
Yijun Wang ◽  
Shengpu Xu ◽  
Xiaorong Gao
Keyword(s):  
Control System ◽  
Visual Stimulation ◽  
Motor Impairment ◽  
Robotic Arm ◽  
Level Control ◽  
Prosthetic Devices ◽  
User Training ◽  
Severe Motor ◽  
Robotic Arm Control ◽  
High Level

Although robot technology has been successfully used to empower people who suffer from motor disabilities to increase their interaction with their physical environment, it remains a challenge for individuals with severe motor impairment, who do not have the motor control ability to move robots or prosthetic devices by manual control. In this study, to mitigate this issue, a noninvasive brain-computer interface (BCI)-based robotic arm control system using gaze based steady-state visual evoked potential (SSVEP) was designed and implemented using a portable wireless electroencephalogram (EEG) system. A 15-target SSVEP-based BCI using a filter bank canonical correlation analysis (FBCCA) method allowed users to directly control the robotic arm without system calibration. The online results from 12 healthy subjects indicated that a command for the proposed brain-controlled robot system could be selected from 15 possible choices in 4[Formula: see text]s (i.e. 2[Formula: see text]s for visual stimulation and 2[Formula: see text]s for gaze shifting) with an average accuracy of 92.78%, resulting in a 15 commands/min transfer rate. Furthermore, all subjects (even naive users) were able to successfully complete the entire move-grasp-lift task without user training. These results demonstrated an SSVEP-based BCI could provide accurate and efficient high-level control of a robotic arm, showing the feasibility of a BCI-based robotic arm control system for hand-assistance.

scholarly journals Review on Patient-Cooperative Control Strategies for Upper-Limb Rehabilitation Exoskeletons

2021 ◽  
Vol 8 ◽  
Author(s):  
Stefano Dalla Gasperina ◽  
Loris Roveda ◽  
Alessandra Pedrocchi ◽  
Francesco Braghin ◽  
Marta Gandolla
Keyword(s):  
Upper Limb ◽  
Cooperative Control ◽  
Control Strategies ◽  
Human Robot Interaction ◽  
Level Control ◽  
Rehabilitation Treatment ◽  
Upper Limb Rehabilitation ◽  
High Level ◽  
Limb Rehabilitation ◽  
Training Modalities

Technology-supported rehabilitation therapy for neurological patients has gained increasing interest since the last decades. The literature agrees that the goal of robots should be to induce motor plasticity in subjects undergoing rehabilitation treatment by providing the patients with repetitive, intensive, and task-oriented treatment. As a key element, robot controllers should adapt to patients’ status and recovery stage. Thus, the design of effective training modalities and their hardware implementation play a crucial role in robot-assisted rehabilitation and strongly influence the treatment outcome. The objective of this paper is to provide a multi-disciplinary vision of patient-cooperative control strategies for upper-limb rehabilitation exoskeletons to help researchers bridge the gap between human motor control aspects, desired rehabilitation training modalities, and their hardware implementations. To this aim, we propose a three-level classification based on 1) “high-level” training modalities, 2) “low-level” control strategies, and 3) “hardware-level” implementation. Then, we provide examples of literature upper-limb exoskeletons to show how the three levels of implementation have been combined to obtain a given high-level behavior, which is specifically designed to promote motor relearning during the rehabilitation treatment. Finally, we emphasize the need for the development of compliant control strategies, based on the collaboration between the exoskeleton and the wearer, we report the key findings to promote the desired physical human-robot interaction for neurorehabilitation, and we provide insights and suggestions for future works.

scholarly journals High-Level Control in Lucid Dreams

2020 ◽  
Vol 40 (1) ◽  
pp. 20-42
Author(s):  
Alexandre Lemyre ◽  
Lidia Légaré-Bergeron ◽  
Roxanne B. Landry ◽  
Donald Garon ◽  
Annie Vallières
Keyword(s):  
Online Survey ◽  
Control Strategies ◽  
Analysis Method ◽  
Level Control ◽  
Consensus Approach ◽  
Content Analysis Method ◽  
Dream Therapy ◽  
High Level ◽  
Verbal Strategies ◽  
Open Question

The objective of the present study is to explore lucid dream control strategies (LDCSs) facilitating the production of outcomes that are impossible in the real world. Participants are 107 adults who experienced at least one lucid dream per year. They completed an online survey including an open question on LDCSs. Responses were analyzed using a content analysis method with a consensus approach. The results revealed five categories of LDCSs used within the lucid dreams: verbal strategies, strategies based on the use of the dream’s objects or environment, strategies based on the use of the oneiric body, strategies based on the management of emotions, and other strategies. Within these categories, 35 LDCSs were identified. These were used individually or in combination. Three additional LDCSs were used in waking. In conclusion, several LDCSs that were identified could be tested in the context of the lucid dream therapy for chronic nightmares.

scholarly journals Energy Space Modeling of Power Electronics in Local Area Power Networks

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Gregory M. Vosters ◽  
Wayne W. Weaver
Keyword(s):  
Power Electronics ◽  
Control Strategies ◽  
Local Area ◽  
Energy Utilization ◽  
State Variables ◽  
Level Control ◽  
Power Networks ◽  
Change Of Variables ◽  
Space Modeling ◽  
High Level

Power electronics are a core enabling technology for local area power networks and microgrids for renewable energy, telecom, data centers, and many other applications. Unfortunately, the modeling, simulation, and control of power electronics in these systems are complicated when using traditional converter models in conjunction with the network nodal equations. This work proposes a change of variables for the power electronic converter models from traditional voltage and currents to input conductance and stored energy. From this change of state, a universal point of load converter model can be utilized in the network nodal equations irrespective of the topology of the converter. The only impact the original converter topology has on the new model is the bounds on the control and state variables, and the mapping back to the switching or duty cycle controls. The proposed approach greatly simplifies the modeling of local area power networks and microgrids. This simpler model can be used to study stability and energy utilization and develop high-level control strategies that were not previously feasible.

Motion Cueing Algorithms: A Review

2017 ◽  
Vol 1 (1) ◽  
pp. 90-106 ◽  
Author(s):  
Sergio Casas ◽  
Ricardo Olanda ◽  
Nilanjan Dey
Keyword(s):  
Predictive Control ◽  
Control Strategies ◽  
General Scheme ◽  
Level Control ◽  
Motion Platform ◽  
Motion Cues ◽  
Vehicle Simulation ◽  
Robotic Motion ◽  
Motion Cueing ◽  
High Level

Robotic motion platforms are commonly used in motion-based vehicle simulation. However, the reproduction of realistic accelerations within a reduced workspace is a major challenge. Thus, high-level control strategies commonly referred to as motion cueing algorithms (MCA) are required to convert the simulated vehicle physical state into actual motion for the motion platform. This paper reviews the most important strategies for the generation of motion cues in simulators, listing the advantages and drawbacks of the different solutions. The motion cueing problem, a general scheme and the four most common approaches – classical washout, adaptive washout, optimal control and model predictive control – are presented. The existing surveys of the state-of-the-art on motion cueing are usually limited to list the MCA or to a particular vehicle application. In this work, a comprehensive vehicle-agnostic review is presented. Moreover, evaluation and tuning of MCA are also considered, classifying the different methods, and providing examples of each class.

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