Design of controller for single axis knee using MR Damper (original) (raw)

Design and Evaluation of a Magnetorheological Damper Based Prosthetic Knee

International Journal of Engineering, 2019

In this work, a magnetorheological (MR) damper based above-knee prosthesis is design and evaluated based on its performance in swing phase and in stance phase. Initially, a dynamic system model for swing phase of a prosthetic leg incorporating a single-axis knee with ideal MR damper was built. The dynamic properties of the damper are represented with Bingham parametric model. From Bingham model, governing damper parameters that determine the damping force and piston displacement of the damper are identified and optimized so as to enable the single-axis knee to nearly mimick the natural swing phase trajectory of a healthy person for level-ground walking as obtained from experimental data. Then, with the optimal damper parameters, an MR damper valve constrained in a desired cylindrical volume is developed. Finally, the prosthetic knee with the MR damper is evaluated for its performance during stance phase, based on ISO standard loading condition for the intended application. The results show that, compare to Rheo knee ® , the MR damper based prosthetic knee has achieved up to 68% reduction by volume and 40% reduction by weight.

Design and Evaluation of Swing Phase Controllers for Single-axis Knee

2016

A prosthetic swing-phase control mechanism simulates the action of thigh musculature to aid in increased gait function. In this work, a hydraulic damper and a magnetorheological (MR) damper are designed as controllers with an objective of evaluating their performance in controlling swing-phase damping in an above-knee prosthesis. Parametric models are utilized to represent dynamic properties of the dampers. Based on the models, control parameters that govern damping force and displacement of the dampers are identified. Parameters of the dampers are determined through optimization that minimizes the error between the prosthesis knee angle trajectories and a desired knee angle trajectory for normal level ground walking from experimental data. Experimental data of thigh and hip motions are introduced as inputs into a dynamic system to determine sets of control parameters. Furthermore, input thigh motion is also deviated to evaluate robustness of the controllers in real application. Com...

Techniques for Dynamic Damping Control in Above Knee Prosthesis

2018

The paper presents a new technique for dynamic damping control based on natural humanoid walk for above knee prosthesis. It has been observed that natural humanoid walking is not solely relied on sensory feed back but also on Central Pattern Generators (CPG) and this CPG produces variation in joint trajectories based on task. Developing task oriented active prosthesis exploiting biologically inspired CPG patterns are of main focus of the paper. Task oriented stable gaits were synthesized using ZMP (Zero Moment Point) approach and the results were compared to kinematics of subjects captured by video streaming. Initial results suggest a feasible solution to gait pattern generation and adjustment of damping profile of prosthetic knee joints to achieve normal humanoid walking.

Optimal design of an MR damper valve for prosthetic knee application

Journal of Mechanical Science and Technology, 2018

In this work, a magnetorheological (MR) damper valve is designed with the primary objective of controlling swing-phase damping in an above-knee prosthesis. Initially, a swing phase model of the desired single axis knee incorporating MR damper was modelled. The control parameters that govern damping force and displacement of the damper were identified and optimized to enable the prosthetic knee to produce near normal swing phase trajectory for ground walking as obtained from experimental data. Then, the MR damper valve is optimally designed by selecting typical performance indices of the damper for the intended application. A multi-objective optimization problem is formulated where the MR damper valve is constrained in a desired cylindrical volume defined by its radius and height. Effects of the geometrical design variables of the valve are analytically investigated by mapping finite element analysis (FEA) numerical responses with response surface method (RSM). The results show that the MR damper with designed damper valve enables the prosthetic knee to achieve near to normal swing phase trajectory, and compare to the existed MR damper, up to 71 % reduction by weight has been achieved.

Development of a Simple and Effcient Above Knee Prosthesis

2003

We present in this paper the state of the art of our research concerning the development of a new semi-active above knee prosthesis. The structure of the prosthesis is exposed. The design and components selection were done taking into account reliable functionality, low cost, low weight, low volume and availability. The control system is based on a micro-controller that ensures functions of locomotion modes recognition and brake control. A simple finite state approach is proposed in order to control the brake and in consequence to enhance patient acceptance and improve the overall functionality of the user.

A study on damping profile for prosthetic knee

Proceedings of the …, 2012

An intelligent prosthetic leg for above knee amputee person has been developed by Indian Institute of Information Technology -Allahabad. The leg has been called as Adaptive Modular Active Leg (AMAL). The main aim of this paper was to generate suitable damping profiles required for above knee prosthetic patients for locomotion. A detailed analysis of human gait cycle is needed to provide damping profiles to the prosthetic knee. This information is obtained from the healthy leg. A simple potentiometer sensor is fitted beside the healthy knee to measure the knee angle and strain gauges mounted below the heel, in the shoe to measure gait strain. These signals from the knee and the heel are the input that describe the gait cycle of the patient. These two signal values are cleaned using Kalman filter to reduce the sensory noise for providing better performance to our system. Human gait cycle is divided into six different phases to evaluate damping profiles. In this paper, we formulate six different damping equations to produce damping profiles for prosthetic knee. The Artificial Neural Network has been used to classify different phase of walking cycle with suitable damping value.

Motor electrical damping for back-drivable prosthetic knee

2016 11th France-Japan & 9th Europe-Asia Congress on Mechatronics (MECATRONICS) /17th International Conference on Research and Education in Mechatronics (REM), 2016

The paper presents a model and analysis of a backdrivable knee prosthesis. In this context, the investigation into the design, modelling and analysis of a back-drivable semiactive prosthetic knee is presented. A mathematical model has been developed for evaluating the electrical damping characteristics of the DC motor in passive mode. The analysis shows that a single actuator could be suitable to work in active mode to provide mechanical power and in passive mode as a damper dissipating energy.

User‐adaptive control of a magnetorheological prosthetic knee

Industrial Robot: An International Journal, 2003

A magnetorheological knee prosthesis is presented that automatically adapts knee damping to the gait of the amputee using only local sensing of knee force, torque, and position. To assess the clinical effects of the user‐adaptive knee prosthesis, kinematic gait data were collected on four unilateral trans‐femoral amputees. Using the user‐adaptive knee and a conventional, non‐adaptive knee, gait kinematics were evaluated on both affected and unaffected sides. Results were compared to the kinematics of 12 age, weight and height matched normals. We find that the user‐adaptive knee successfully controls early stance damping, enabling amputee to undergo biologically‐realistic, early stance knee flexion. These results indicate that a user‐adaptive control scheme and local mechanical sensing are all that is required for amputees to walk with an increased level of biological realism compared to mechanically passive prosthetic systems.

Design and evaluation of a hydraulic mechanism with available components for passive knee prostheses

Disability and Rehabilitation: Assistive Technology, 2019

Background: Hydraulic knee prosthesis can provide stance phase control and swing phase control suitable for active persons with an amputation. However, typical commercial hydraulic knees are costly and require frequent maintenance making them inaccessible for persons with an amputation in low-income countries. The objective of this article is to present a new design for a low-cost hydraulic knee prosthesis. Method: The prototype hydraulic knee is made of simple hydraulic components. The hydraulic system was designed to provide flexion locking during the stance phase and damping during the swing phase of gait. Results: The prototype was tested and results show that the hydraulic knee can prevent flexion of the knee at stance phase when the highest external knee flexion moment in the gait cycle occurs. The prototype mechanism is capable of resisting flexion torque of 60 N-m. Conclusions: The prototype hydraulic knee can be assembled from available hydraulic components for low cost and ease of maintenance which is feasible for persons with an amputation in lowincome countries. ä IMPLICATIONS FOR REHABILITATION A new design hydraulic knee which assembled from simple hydraulic components which provide both stance control and swing control. The use of simple hydraulic components makes the knee feasible for low-income country where service and maintenance staff is inadequate.