Two-link lower limb exoskeleton model control enhancement using computed torque

Robotic technology has recently been used to help stroke patients with gait and balance rehabilitation. Rehabilitation robots such as gait trainers are designed to assist patients in systematic, repetitive training sessions to speed up their recovery from injuries. Several control algorithms are commonly used on exoskeletons, such as proportional, integral and derivative (PID) as linear control. However, linear control has several disadvantages when applied to the exoskeleton, which has the problem of uncertainties such as load and stiffness variations of the patient’s lower limb. To improve the lower limb exoskeleton for the gait trainer, the computed torque controller (CTC) is introduced as a control approach in this study. When the dynamic properties of the system are only partially known, the computed torque controller is an essential nonlinear controller. A mathematical model forms the foundation of this controller. The suggested control approach’s effectiveness is evaluated using a model or scaled-down variation of the method. The performance of the suggested calculated torque control technique is then evaluated and contrasted with that of the PID controller. Because of this, the PID controller’s steady-state error in the downward direction can reach 5.6%, but the CTC can lower it to 2.125%

Control of robot-assisted gait trainer using hybrid proportional integral derivative and iterative learning control

An inexpensive exoskeleton of the lower limb was designed and developed in this study. It can be used as a gait trainer for persons with lower limb problems. It plays an essential role in lower limb rehabilitation and aid for patients, and it can help them improve their physical condition. This paper proposes a hybrid controller for regulating the lower limb exoskeleton of a robot-assisted gait trainer that uses a proportional integral and derivative (PID) controller combined with an iterative learning controller (ILC). The direct current motors at the hip and knee joints are controlled by a microcontroller that uses a preset pattern for the trajectories. It can learn how to monitor a trajectory. If the trajectory or load is changed, it will be able to follow the change. The experiment showed that the PID controller had the smallest overshoot, and settling time, and was responsible for system stability. Even if there are occasional interruptions, the tracking performance improves with the ILC

Microcontroller Based Simple Water Flow Rate Control System to Increase the Efficiency of Solar Energy Water Distillation

The current problem of solar energy water distillation is in its low efficiency. Low efficiency is caused by inefficient water evaporation processes. Increasing the efficiency of water evaporation is done by controlling the rate of water entering into the absorber. The commonly used mechanical control system still has weaknesses such as the instability of the water entering the absorber. This causes less effective evaporation of water so that the resulting distillation efficiency is not optimal. The water rate input system for distillation in this study is based on a simple microcontroller. The microcontroller-based input water rate control system allows the rate of input water with a small but continuous flow rate so that the water evaporation process can be more effective. This study aims to improve the efficiency of solar energy water distillation by increasing the efficiency of the water evaporation process through controlling the flow rate of water inlet. The research was carried out by the experimental method. The parameters varied were: the rate of input water which was 0.3 l / hour, 0.5 l / hour and 1.2 l / hour. Parameters measured in this study were: (1) temperature of absorber, (2) temperature of the cover glass , (3) temperature of cooling water, (4) input water temperature, (5) ambient air temperature, (6) distilled water results, (7) solar energy coming in and (8) time of recording data. The results showed that the production of distillation water using microcontroller-based water rate control was a maximum of 523% compared to the model without water rate control at a water flow rate of 0.3 liters / hour, with distillation efficiency of 66%. From the results of this study it can also be concluded that microcontroller based water flow rate controller is more stable than mechanical water flow controller, especially in small flo

Pelacak Matahari Dua Sumbu Menggunakan LDR untuk Meningkatkan Absorbsi Matahari

The position of the sun in the sky always changes periodically. A lot of research has been doneto follow the sun's motion using a solar tracking system to increase the amount of solar energy that can be absorbed. The solar tracking system can be grouped into passive and active system. Active sun tracker system uses motor drive in following the motion of the sun. The current active tracking system is using one or two rotary axis. Active two-axis solar tracking system provides greater efficiency and effectiveness than one-axis solar tracking system. This study aims to increase the absorbable sun energy with a simpletwo-axis solar tracking system. This research has been done by experimental method by making a model of two-axis sun tracker and its field data retrieval. The main parts of the model in this study are (1) LDR sensor, (2) microcontroller and (3) motor drive. Initial data of field test results shows a maximum increase (269%) in absorbable solar energy on a model using a sun tracker than models that d o not use a solar tracking systemKeywords: tracker, sun, two-axis rotate, simpl

Wearable Activity Monitoring System for Detection of Estrus in A Sheep Farm

We have carried out the design of estrus detection tool for the large-scale farm of sheep. Estrus is a regular period of sexual receptivity in female mammals. Basically there are some ways to determine the time of estrus in cattle, which is based on body heat, bioimpedance or motion (activity). These tools have been used in some large-scale farms in developed countries. While in developing countries they are less popular because the price is quite expensive. In this study, a low cost system is designed based on the method of activity measurement using IMU sensor. Activities of sheep sensed by the IMU sensor will be processed by a microcontroller, then to be sent wirelessly to a remote monitor computer.

Microcontroller Based Simple Water Flow Rate Control System to Increase the Efficiency of Solar Energy Water Distillation

Masalah distilasi air energi surya saat ini adalah efisiensinya yang rendah. Efisiensi rendah disebabkan oleh proses penguapan air yang tidak efisien. Peningkatan efisiensi penguapan air dilakukan dengan mengendalikan laju air yang masuk ke absorber. Sistem kontrol mekanis yang umum digunakan masih memiliki kelemahan seperti ketidakstabilan air memasuki penyerap. Hal ini menyebabkan penguapan air kurang efektif sehingga efisiensi destilasi yang dihasilkan tidak optimal. Sistem input laju air untuk distilasi dalam penelitian ini didasarkan pada mikrokontroler sederhana. Sistem kontrol laju air masukan berbasis mikrokontroler memungkinkan laju air masukan dengan laju aliran kecil namun kontinu sehingga proses penguapan air bisa lebih efektif. Penelitian ini bertujuan untuk meningkatkan efisiensi penyulingan air energi surya dengan meningkatkan efisiensi proses penguapan air melalui pengontrolan laju aliran air masuk. Penelitian ini dilakukan dengan metode eksperimental. Parameter yang bervariasi adalah: laju air input yaitu 0,3 l / jam, 0,5 l / jam dan 1,2 l / jam. Parameter yang diukur dalam penelitian ini adalah: (1) suhu absorber, (2) suhu kaca penutup, (3) suhu air pendingin, (4) suhu air input, (5) suhu udara sekitar, (6) air suling hasil, (7) energi matahari masuk dan (8) waktu perekaman data. Hasil penelitian menunjukkan bahwa produksi air destilasi menggunakan kontrol laju air berbasis mikrokontroler adalah maksimum 523% dibandingkan dengan model tanpa kontrol laju air pada laju aliran air 0,3 liter / jam, dengan efisiensi distilasi sebesar 66%. Dari hasil penelitian ini juga dapat disimpulkan bahwa pengontrol laju aliran air berbasis mikrokontroler lebih stabil daripada pengontrol aliran air mekanik, terutama pada aliran kecil