Control of a Prosthetic Arm Using fNIRS, a Neural-Machine Interface

Development in the field of bio-mechatronics has provided diverse ways to mimic and improve the function of human limbs. Without an elbow joint, the hand remains stiff because all the muscles tension passes through this joint. Advanced myoelectric prosthetic devices are limited due to the lack of appropriate signal sources on residual amputee muscles and insufficient real-time control. Neural-machine interfaces (NMI) are representing a recent approach to develop effective applications. In this research study, an NMI is designed that presents real-time signal processing for command generation. The human brain hemodynamic responses are, therefore, translated into control commands for people suffering from transhumeral amputation. A novel and first of its kind scheme is proposed which utilizes functional near-infrared spectroscopy (fNIRS) to generate the control commands for a three-degree-of-freedom (DOF) prosthetic arm. The time window for fNIRS signals was set to 1 second. The average accuracy was found to be 82% which is a state-of-the-art result for such a technique. The accuracy ranged from 65 to 85% subject-wise. The data were trained and tested on both artificial neural network (ANN) and linear discriminant analysis (LDA). Eight out of 10 motions were correctly predicted in real time by both classifiers

Energy efficient parallel configuration based six degree of freedom machining bed

The process of material removal from a workpiece to obtain the desired shape is termed machining. Present-day material removal technologies have high spindle speeds and thus allow quick material removal. These high-speed spindles are highly exposed to vibrations and, as a result, the accuracy of the final workpiece’s dimensions is compromised. To overcome this problem, the motion of the tool is restricted, and multiple degrees of freedom are given through the motion of the workpiece in different axes. A machining bed configured as a parallel manipulator capable of giving six degrees of freedom (DOF) to the workpiece is proposed in this regard. However, the proposed six DOF machining bed should be energy efficient to avoid an increase in machining cost. The benefit of using the proposed configuration is a reduction in dimensional error and computational time which, as a result, reduces the energy utilization, vibrations, and machining time in practice. This paper presents kinematics, dynamics and energy efficiency models, and the development of the proposed configuration of the machining bed. The energy efficiency model is derived from the dynamics model. The models are verified in simulation and experimentally. To minimize error and computation time, a PID controller is also designed and tested in simulation as well as experimentally. The resulting energy efficiency is also analyzed. The results verify the efficacy of the proposed configuration of the machining bed, minimizing position error to 2% and reducing computation time by 27%, hence reducing the energy consumption and enhancing the energy efficiency by 60%

Design of Portable Exoskeleton Forearm for Rehabilitation of Monoparesis Patients Using Tendon Flexion Sensing Mechanism for Health Care Applications

Technology plays a vital role in patient rehabilitation, improving the quality of life of an individual. The increase in functional independence of disabled individuals requires adaptive and commercially available solutions. The use of sensor-based technology helps patients and therapeutic practices beyond traditional therapy. Adapting skeletal tracking technology could automate exercise tracking, records, and feedback for patient motivation and clinical treatment interventions and planning. In this paper, an exoskeleton was designed and subsequently developed for patients who are suffering from monoparesis in the upper extremities. The exoskeleton was developed according to the dimensions of a patient using a 3D scanner, and then fabricated with a 3D printer; the mechanism for the movement of the hand is a tendon flexion mechanism with servo motor actuators controlled by an ATMega2560 microcontroller. The exoskeleton was used for force augmentation of the patient’s hand by taking the input from the hand via flex sensors, and assisted the patient in closing, opening, grasping, and picking up objects, and it was also able to perform certain exercises for the rehabilitation of the patient. The exoskeleton is portable, reliable, durable, intuitive, and easy to install and use at any time

APPLICATION OF CORMIX MODEL TO THE THERMAL DISCHARGES FROM POWER STATIONS - A CASE STUDY

The behaviour of the thermal water discharge from Shannonbridge Power Station (Co. Offaly. Ireland) into the river Shannon was investigated using the CORMIX model. The flow rate and temperature data measured at low flow conditions in summer were used in this study. The water quality standard of 3 dgree celsius rise in ambient water temperature was used for thermal plume study. The geometry of thermal plume was simulated using different angle of discharge channel and bottom slope of the river near discharge channel. The results showed that the discharge channel geometry and depth of water at discharge point are important parameters. But the most effective parameter is the horizontal discharge angle i.e. the actual angle of discharge channel with the river ban downstream.lt affects both the temperature distribution and the mixing zone length. The water quality standard was obtained at a distance of 15.75 m downstream when horizontal angle of discharge was 20 degree . While the same standard was obtained in flow establishment zone (0.25 m downstream) with cross flow (i.e. with horizontal angle of discharge of 90 drgree ). It is ' proposed for Shannonbridge Power Station that the thermal water discharge from power station be normal to the downstream bank of river (cross flow). It is also suggested that define a regulatory mixing zone length of 20 m downstream in river. Shannon to keep it environmentally safe

The Effect of Terrain Inclination on Performance and the Stability Region of Two-Wheeled Mobile Robots

Two-wheeled mobile robots (TWMRs) have a capability of avoiding the tip-over problem on inclined terrain by adjusting the centre of mass position of the robot body. The effects of terrain inclination on the robot performance are studied to exploit this capability. Prior to the real-time implementation of position control, an estimation of the stability region of the TWMR is essential for safe operation. A numerical method to estimate the stability region is applied and the effects of inclined surfaces on the performance and stability region of the robot are investigated. The dynamics of a TWMR is modelled on a general uneven terrain and reduced for cases of inclined and horizontal flat terrain. A full state feedback (FSFB) controller is designed based on optimal gains with speed tracking on a horizontal flat terrain. The performance and stability regions are simulated for the robot on a horizontal flat and inclined terrain with the same controller. The results endorse a variation in equilibrium points and a reduction in stability region for robot motion on inclined terrain

Patient's intention detection and control for sit-stand mechanism of an assistive device for paraplegics

Rehabilitation and assistive technologies are touching new bounds of excellence due to the advent of more user friendly human–machine interfaces (HMI) and ergonomic design principles. Among the most fundamental movements which are required in performing activities of daily living is the sit and stand motion, a device is proposed in this study which enables a patient to perform his activities of daily living (ADL) tasks by enabling them to sit, stand and move without the need of an assistant. The device, in this study, is proposed to be activated by an electroencephalogram (EEG) based intention acquisition system. The intention is acquired from eye blinks. The EEG based intention detection system converts eye blinks to respective commands after classification of eye blink signals collected using EMOTIVE® EPOCH+ headset. These control commands then trigger the control algorithm which then actuates and controls the system states. For the later, two control schemes namely proportional integral derivative (PID) control and sliding mode control (SMC) are tested in this study. The simulation and experimental results are given. The experimental setup consists of an offline EEG signal classification module, Simulink® model and the prototype of the actual device. It is concluded that SMC performs far better than PID for control of the assistive device in ensuring patient comfort during motion

Experimental Thermal Response Study of Multilayered, Encapsulated, PCM-Integrated Building Construction Materials

Thermal energy storage integration using phase change materials (PCMs) in buildings has great potential for energy conservation and greenhouse gas (GHG) emission reduction. Cutting-edge research and innovative ideas are required when using multilayered PCMs within typical construction materials to take advantage of their heat storage capability over a wide temperature range within buildings. This current study was carried out to experimentally test the efficacy of using dual PCMs RT28HC and RT21HC with different melting temperature ranges (28 °C and 21 °C) under variable thermal loading. The transient thermal response of various PCM-based configurations of concrete and cement blocks at different temperature inputs was obtained to determine the effectiveness of dual PCMs and their optimized configuration under experimental laboratory conditions. The range of the temperature input was varied from 22 °C to 50 °C, suitable for hot climatic conditions such as those in Pakistan. Laboratory ambient temperatures remained at ~17 °C for all experimental tests. Moreover, the results were compared using two parameters, i.e., decrement factor (DF) and time lag (TL). With DF and TL values of 0.10 and 5.72, respectively, in the high-temperature heating (HTH) regime and a low DF value of 0.08 and high TL of 5.17 in the moderate-temperature heating (MTH) regime, the RT28HC–RT21HC combination proved to be the most effective. The application of the RT28HC–RT21HC combination provided up to a 54.3% reduction in indoor temperatures in the HTH regime. This research contributes through experimental validation that these novel configurations are capable of providing substantial improvement in indoor thermal comfort

Experimental Thermal Response Study of Multilayered, Encapsulated, PCM-Integrated Building Construction Materials

Thermal energy storage integration using phase change materials (PCMs) in buildings has great potential for energy conservation and greenhouse gas (GHG) emission reduction. Cutting-edge research and innovative ideas are required when using multilayered PCMs within typical construction materials to take advantage of their heat storage capability over a wide temperature range within buildings. This current study was carried out to experimentally test the efficacy of using dual PCMs RT28HC and RT21HC with different melting temperature ranges (28 °C and 21 °C) under variable thermal loading. The transient thermal response of various PCM-based configurations of concrete and cement blocks at different temperature inputs was obtained to determine the effectiveness of dual PCMs and their optimized configuration under experimental laboratory conditions. The range of the temperature input was varied from 22 °C to 50 °C, suitable for hot climatic conditions such as those in Pakistan. Laboratory ambient temperatures remained at ~17 °C for all experimental tests. Moreover, the results were compared using two parameters, i.e., decrement factor (DF) and time lag (TL). With DF and TL values of 0.10 and 5.72, respectively, in the high-temperature heating (HTH) regime and a low DF value of 0.08 and high TL of 5.17 in the moderate-temperature heating (MTH) regime, the RT28HC–RT21HC combination proved to be the most effective. The application of the RT28HC–RT21HC combination provided up to a 54.3% reduction in indoor temperatures in the HTH regime. This research contributes through experimental validation that these novel configurations are capable of providing substantial improvement in indoor thermal comfort

Linear Active Disturbance Rejection Control for a Laser Powder Bed Fusion Additive Manufacturing Process

Functional metal parts with complicated geometry and internal features for the aerospace and automotive industries can be created using the laser powder bed fusion additive manufacturing (AM) technique. However, the lack of uniform quality of the produced parts in terms of strength limits its enormous potential for general adoption in industries. Most of the defects in selective laser melting (SLM) parts are associated with a nonuniform melt pool size. The melt pool area may fluctuate in spite of constant SLM processing parameters, like laser power, laser speed, hatching distance, and layer thickness. This is due to heat accumulation in the current track from previously scanned tracks in the current layer. The feedback control strategy is a promising tool for maintaining the melt pool dimensions. In this study, a dynamic model of the melt pool cross-sectional area is considered. The model is based on the energy balance of lumped melt pool parameters. Energy coming from previously scanned tracks is considered a source of disturbance for the current melt pool cross-section area in the control algorithm. To track the reference melt pool area and manage the disturbances and uncertainties, a linear active disturbance rejection control (LADRC) strategy is considered. The LADRC control technique is more successful in terms of rapid reference tracking and disturbance rejection when compared to the conventional PID controller. The simulation study shows that an LADRC control strategy presents a 65% faster time response than the PID, a 97% reduction in the steady state error, and a 98% reduction in overshoot. The integral time absolute error (ITAE) performance index shows 95% improvement for reference tracking of the melt pool area in SLM. In terms of reference tracking and robustness, LADRC outperforms the PID controller and ensures that the melt pool size remains constant