A Control Strategy for an Active Alignment Transtibial Prosthesis

2015 ◽  
Author(s):  
Andrew LaPrè ◽  
Frank Sup
Keyword(s):  
Gait Cycle ◽  
Mechanical Design ◽  
Adaptive Controller ◽  
Residual Limb ◽  
Control Approach ◽  
Prosthetic Foot ◽  
Transtibial Prosthesis ◽  
Finite State ◽  
New Type ◽  
Walking Speeds

This paper presents a control approach for an experimental transtibial prosthesis that can actively realign the residual limb in relation to prosthetic foot during the stance phase of gait. The realignment objective is to inject positive power into the gait cycle while actively reducing the magnitude of the sagittal moment transferred to the residual limb. The altered gait dynamics of this new type of prosthesis require a control approach that coordinates its function with a user’s gait cycle. This paper overviews the mechanical design of the prosthesis development, the proposed finite-state adaptive controller, and presents experimental results for constant cadence walking and adaptation while changing walking speeds.

Stiffness Control of an Active Transtibial Prosthesis

2018 ◽  
Author(s):  
Joseph G. Klein ◽  
Philip A. Voglewede
Keyword(s):  
Emg Activity ◽  
State Control ◽  
Simulink Model ◽  
Spiral Spring ◽  
Transtibial Prosthesis ◽  
Finite State ◽  
In Series ◽  
New Type ◽  
Stiffness Control ◽  
Finite State Control

Active, transtibial prostheses typically use finite state control algorithms that struggle with cadence and gait variability of the amputee. Recent work in artificial neural networks (ANN) have shown the possibility to predict the users intent based on EMG activity and the current position of the ankle, which can be used as an input signal into an improved controller. This paper examines how to implement an ANN signal into a zero order impedance controller, i.e., a stiffness controller, on a specific active transtibial prosthesis. The prosthesis incorporates a linear spiral spring in parallel with a four-bar mechanism. In order to implement stiffness control, the spring was moved to being in series with the four-bar mechanism to establish a relationship between the torque of the spring and the position of the motor. To ensure stiffness control is feasible, a MATLAB Simulink model of the system was created to test the robustness of the controller and the effect of moving the spring from parallel to series. The robustness of the controller was verified as the ankle position and torque requirements are met in the simulation. The Simulink model accurately models the new system and can be used in the future to optimize the motor or the four-bar mechanism for this new type of control.

scholarly journals Neuromechanical force-based control of a powered prosthetic foot

2020 ◽  
Vol 1 ◽  
Author(s):  
Amirreza Naseri ◽  
Martin Grimmer ◽  
André Seyfarth ◽  
Maziar Ahmad Sharbafi
Keyword(s):  
Sensory Feedback ◽  
Reaction Force ◽  
Neuromuscular Control ◽  
Target Population ◽  
Vertical Ground Reaction Force ◽  
Control Approach ◽  
Prosthetic Foot ◽  
Ankle Torque ◽  
Study Support ◽  
Walking Speeds

Abstract This article presents a novel neuromechanical force-based control strategy called FMCA (force modulated compliant ankle), to control a powered prosthetic foot. FMCA modulates the torque, based on sensory feedback, similar to neuromuscular control approaches. Instead of using a muscle reflex-based approach, FMCA directly exploits the vertical ground reaction force as sensory feedback to modulate the ankle joint impedance. For evaluation, we first demonstrated how FMCA can predict human-like ankle torque for different walking speeds. Second, we implemented the FMCA in a neuromuscular transtibial amputee walking simulation model to validate if the approach can be used to achieve stable walking and to compare the performance to a neuromuscular reflex-based controller that is already used in a powered ankle. Compared to the neuromuscular model-based approach, the FMCA is a simple solution with a sufficient push-off that can provide stable walking. Third, to assess the ability of the FMCA to generate human-like ankle biomechanics during walking at the preferred speed, we implemented this strategy in a powered prosthetic foot and performed experiments with a non-amputee subject. The results confirm that, for this subject, FMCA can be used to mimic the non-amputee reference ankle torque and the reference ankle angle. The findings of this study support the applicability and advantages of a new bioinspired control approach for assisting amputees. Future experiments should investigate the applicability to other walking speeds and the applicability to the target population.

scholarly journals A Review of Existing Transtibial Bionic Prosthesis: Mechanical Design, Actuators and Power Transmission

2022 ◽  
Vol 1 (2) ◽  
pp. 65-72
Author(s):  
Ade Reza Ismawan ◽  
Rifky Ismail ◽  
Tony Prahasto ◽  
Mochammad Ariyanto ◽  
Budi Setiyana
Keyword(s):  
Gait Cycle ◽  
Power Transmission ◽  
Mechanical Design ◽  
Body Part ◽  
Gait Pattern ◽  
Metabolic Energy ◽  
Human Gait ◽  
Transtibial Prosthesis ◽  
Selection Of

Transtibial and transfemoral amputations are the most common amputations in the world, loss of lower extremity result in impaired function extremities and also body balance. A prosthesis is a medical device designed to replace a specific body part to restore function to a body part lost due to an accident or disease. Most doctors strongly recommend the use of a prosthesis so that patients can return to normal activities after undergoing an amputation. Besides functioning to support beauty, the use of prostheses is also to restore the quality of life of prosthetic users, the issue of metabolic energy consumption when walking is also very important in designing transtibial bionic prosthesis because it involves the comfort of the user transtibial prosthesis. Most of the existing transtibial prosthesis products in Indonesia are conventional passive transtibial foot products, and passive prosthesis users show a limp or asymmetrical gait pattern so that conventional passive prosthesis users experience discomfort when walking in the form of pain in the amputated leg and normal foot, which can cause secondary musculoskeletal injuries such as joint disorders. Passive prostheses cannot generate propulsive force during push-off phase (terminal stance and preswing) of the human gait cycle. The use of passive prostheses can also consume 20-30% more metabolic energy while walking so that it can cause fatigue for the user. Transtibial bionic prosthesis research is growing, transtibial bionic prosthesis can overcome the weakness of passive prosthesis because it can produce push-off during gait cycle and several researchers have shown that bionic prostheses are capable of mimicking the human gait, as well as improve the  performance in a more natural gait and normal walking. This study aims to study the existing transtibial bionic prosthesis by comparing between 6 existing designs of powered ankle or transtibial bionic prosthesis that have been published in several publications. The discussion focuses on the design and mechanical systems, actuators related to the selection of motors and drive mechanisms as well as power transmission from actuators to moving components.

scholarly journals An Adaptive Neuro-Fuzzy Control of Pneumatic Mechanical Ventilator

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 51
Author(s):  
Jozef Živčák ◽  
Michal Kelemen ◽  
Ivan Virgala ◽  
Peter Marcinko ◽  
Peter Tuleja ◽  
...  
Keyword(s):  
Control System ◽  
Control Algorithm ◽  
Fuzzy Inference ◽  
Fuzzy Controller ◽  
Mechanical Design ◽  
Mechanical Ventilator ◽  
Mechanical Ventilators ◽  
Inference System ◽  
Control Approach ◽  
Neuro Fuzzy

COVID-19 was first identified in December 2019 in Wuhan, China. It mainly affects the respiratory system and can lead to the death of the patient. The motivation for this study was the current pandemic situation and general deficiency of emergency mechanical ventilators. The paper presents the development of a mechanical ventilator and its control algorithm. The main feature of the developed mechanical ventilator is AmbuBag compressed by a pneumatic actuator. The control algorithm is based on an adaptive neuro-fuzzy inference system (ANFIS), which integrates both neural networks and fuzzy logic principles. Mechanical design and hardware design are presented in the paper. Subsequently, there is a description of the process of data collecting and training of the fuzzy controller. The paper also presents a simulation model for verification of the designed control approach. The experimental results provide the verification of the designed control system. The novelty of the paper is, on the one hand, an implementation of the ANFIS controller for AmbuBag pressure control, with a description of training process. On other hand, the paper presents a novel design of a mechanical ventilator, with a detailed description of the hardware and control system. The last contribution of the paper lies in the mathematical and experimental description of AmbuBag for ventilation purposes.

A Future Micro Hydro-Propulsive System

1999 ◽  
Author(s):  
Javid Bayandor ◽  
Sylvester Abanteriba ◽  
Ian Bates
Keyword(s):  
Parametric Study ◽  
Mechanical Design ◽  
Theoretical Simulation ◽  
New Type

Abstract This paper discusses the development of production of a new type of hydro-propulsive system for the generation of the power. First, the principles which seek to quantitatively describe the behavior of this unconventional system are established. A brief description of the mechanical design is included. A parametric study of the major influences on the performance of the system has been carried out and discussed. Finally, the comparison of theoretical simulation and experimental is indicated and discussed in detail.

scholarly journals Adjustable sockets may improve residual limb fluid volume retention in transtibial prosthesis users

2019 ◽  
Vol 43 (3) ◽  
pp. 250-256 ◽  
Author(s):  
Jacob T Brzostowski ◽  
Brian G Larsen ◽  
Robert T Youngblood ◽  
Marcia A Ciol ◽  
Brian J Hafner ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Fluid Volume ◽  
Residual Limb ◽  
Short Term ◽  
Transtibial Prosthesis ◽  
Activity Cycles ◽  
Long Term Retention ◽  
Volume Retention ◽  
Intervention Condition

Background: Loss of residual limb volume degrades socket fit and may require accommodation. Objectives: To examine if either of two accommodation strategies executed during resting, socket release with full socket size return and socket release with partial socket size return, enhanced limb fluid volume retention during subsequent activity. Study design: Two repeated-measures experiments were conducted to assess the effects of socket release on limb fluid volume retention. Methods: Limb fluid volume was monitored while participants wore a socket with a single adjustable panel. Participants performed eight activity cycles that each included 10 min of sitting and 2 min of walking. The socket’s posterior panel and pin lock were released during the fifth cycle while participants were sitting. In one experiment (Full Return), the socket was returned to its pre-release size; in a second experiment (Partial Return), it was returned to 102% of its pre-release size. Short-term and long-term limb fluid volume retention were calculated and compared to a projected, No Intervention condition. Results: Partial Return and Full Return short-term retentions and Partial Return long-term retention were greater than those projected under the control condition ( p < 0.05). Conclusion: Socket release during resting after activity, particularly when the socket is returned to a slightly larger size, may be an effective accommodation strategy to reduce fluid volume loss in transtibial prosthesis users. Clinical relevance This study suggests that existing prosthetic technologies’ adjustable sockets and locking pin tethers can be used in novel ways to help maintain residual limb fluid volume in active prosthesis users.

scholarly journals Mechatronic Control System for a Compliant and Precise Pneumatic Rotary Drive Unit

Actuators ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
Johannes T. Stoll ◽  
Kevin Schanz ◽  
Andreas Pott
Keyword(s):  
State Feedback ◽  
Position Control ◽  
Mechanical Design ◽  
Control Algorithms ◽  
Field Oriented Control ◽  
Pneumatic Drive ◽  
Drive Unit ◽  
Control Approach ◽  
Human Robot Collaboration ◽  
Rotary Drive

Robots that enable safe human-robot collaboration can be realized by using compliant drive units. In previous works, different mechanical designs of compliant pneumatic rotary drive units with similar characteristics have been presented. In this paper, we present the overall control approach that we use to operate one of these compliant pneumatic rotary drive units. We explain the mechanical design and derive the differential equation that describes the dynamics of the system. In order to successfully operate a pneumatic drive unit with three or more working chambers, the torque specified by the controller has to be split up onto the working chambers. We transfer the well-known field-oriented control approach from electric motors to the investigated pneumatic drive unit to create such a torque mapping. Moreover, we develop optimized torque mappings that are tailored to work with this type of drive unit. Furthermore, we introduce and compare two control algorithms based on different implementations of state feedback to realize position control. Finally, we present the step responses that we achieve when we implement either one of the control algorithms in combination with the different torque mappings.

Tuning an adaptive controller using a robust control approach

2006 ◽  
Vol 39 (2) ◽  
pp. 561-566
Author(s):  
Jesse Huebsch ◽  
Hector Budman
Keyword(s):  
Robust Control ◽  
Adaptive Controller ◽  
Control Approach

scholarly journals Passive Prosthetic Foot Shape and Size Optimization Using Lower Leg Trajectory Error

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Kathryn M. Olesnavage ◽  
Victor Prost ◽  
William Brett Johnson ◽  
Amos G. Winter
Keyword(s):  
Mechanical Design ◽  
Three Dimensional ◽  
Field Trials ◽  
Lower Leg ◽  
Element Analysis ◽  
Trajectory Error ◽  
Design Objective ◽  
Prosthetic Foot ◽  
Single Part ◽  
Shape And Size

A method is presented to optimize the shape and size of a passive, energy-storing prosthetic foot using the lower leg trajectory error (LLTE) as the design objective. The LLTE is defined as the root-mean-square error between the lower leg trajectory calculated for a given prosthetic foot's deformed shape under typical ground reaction forces (GRFs), and a target physiological lower leg trajectory obtained from published gait data for able-bodied walking. Using the LLTE as a design objective creates a quantitative connection between the mechanical design of a prosthetic foot (stiffness and geometry) and its anticipated biomechanical performance. The authors' prior work has shown that feet with optimized, low LLTE values can accurately replicate physiological kinematics and kinetics. The size and shape of a single-part compliant prosthetic foot made out of nylon 6/6 were optimized for minimum LLTE using a wide Bezier curve to describe its geometry, with constraints to produce only shapes that could fit within a physiological foot's geometric envelope. Given its single part architecture, the foot could be cost effectively manufactured with injection molding, extrusion, or three-dimensional printing. Load testing of the foot showed that its maximum deflection was within 0.3 cm (9%) of finite element analysis (FEA) predictions, ensuring the constitutive behavior was accurately characterized. Prototypes were tested on six below-knee amputees in India—the target users for this technology—to obtain qualitative feedback, which was overall positive and confirmed the foot is ready for extended field trials.

Tuning an adaptive controller using a robust control approach

2009 ◽  
Vol 82 (5) ◽  
pp. 894-909 ◽  
Author(s):  
Jesse Huebsch ◽  
Luis Alberto Ricardez Sandoval ◽  
Hector Budman
Keyword(s):  
Robust Control ◽  
Adaptive Controller ◽  
Control Approach
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