  The simple passive dynamic walker can walk down a shallow downhill slope with no external control or energy input. Nevertheless, the period-one gait stability is only possible over a very narrow range of slopes. Since the passive gaits are extremely sensitive to slope angles, it is important to use a control strategy in order to achieve a wide range of stable walking. The computed torque method is proposed here to produce stable period-one gait cycles for different slopes. In this present method, the unstable walking gait is stabilized by a stable period-one gait pattern on a small specific slope. The proposed approach is illustrated by the simplest passive walkers with point and curved feet. Simulation results reveal the usefulness of this control method for improvement in stability properties of the models.

https://www.ije.ir/article_72420_b2a61d58521af6d2df8d987d6a83b7cf.pdf

Stabilization and Walking Control for a Simple Passive Walker Using Computed Torque Method (RESEARCH NOTE)

Rehabilitation robotics is a recent kind of service robot that include devices such as robotic prosthesis and exoskeletons. These devices could help motor disabled people to rehabilitate their motor functions, and could provide functional compensation to accomplish motor activities. In order to control robotic prosthesis and exoskeletons it is required to identify human movement intention, to be converted into commands for the device. Motor impaired people may use surface electromyography (sEMG) signals to control these devices, taking into account that sEMG signals directly reflects the human motion intention. Myoelectric control is an advanced technique related with the detection, processing, classification, and application of sEMG signals to control human-assisting robots or rehabilitation devices. Despite recent advances with myoelectric control algorithms, currently there is still an important need to develop suitable methods involving usability, for controlling prosthesis and exoskeletons in a natural way. Traditionally, acquiring EMG signals and developing myoelectric control algorithms require expensive hardware. With the advent of low-cost technologies (i.e. sensors, actuators, controllers) and hardware support of simulation software packages as Matlab, affordable research tools could be used to develop novel myoelectric control algorithms. This work describes the implementation and validation of a Matlab-based robotic arm using low-cost technologies such as Arduino commanded using myoelectric control. The platform permits implementation of a variety of EMG-based algorithms. It was carried out a set of experiments aimed to evaluate the platform, through an application of pattern recognition based myoelectric control to identify and execute seven movements of the robotic upper limb: 1-forearm pronation; 2- forearm supination; 3-wrist flexion; 4-wrist extension; 5- elbow flexion; 6- elbow extension; 7-resting. The algorithm use a feature extraction stage based on a combination of time and frequency domain features (mean absolute value, waveform length, root mean square) and a widely used k-NN classifier. Obtained mean classification errors were 5.9%. As future work, additional features in the myoelectric control algorithm will be evaluated, for real-time applications.

A Low-Cost Arm Robotic Platform based on Myoelectric Control for Rehabilitation Engineering

This paper presents experimental analysis of wheeled mobile robots. Mathematical modelling of the mobile robot is presented. The mobile robots consist of an omni-directional and three differential drive mobile robots are tested and moved in given trajectories and the systematic errors of the robots are determined. A new method for omni-direction mobile robot was introduced in which the robot was programmed to move in direction of each wheel shaft. Finally, the mobile robot is moved in given trajectories and the systematic errors of the robot are determined.

https://www.ije.ir/article_71579_8818d7ac150a448d0f3e44396fdc898b.pdf

Experimental analysis for measuring errors in wheeled mobile robots (research note)

With the increasing number of people who have problems with their walking, a new type of gait rehabilitation training robot has been put forward and designed. In order to meet the requirements of the gait rehabilitation training, the whole mechanical structure and control system have been designed, and the model machine for gait rehabilitation training robot has been made. Using the human gait analysis system of the INSENCO, a large number of experiments on human bodies have been carried out, and human gait parameters have been measured and recorded. As has been shown in the experiments, the designed robot has achieved the goal of free movement and weight-reducing; the weight-reducing device is flexible in height and pull, which has accomplished the aim of rehabilitation training. doi: 10.5829/idosi.ije.2016.29.09c.18

J. Zhang

Papers

The Design and Realization of a Gait Rehabilitation Training Robot with Body Supporting Mechanism