Embedded fuzzy logic controller for positive and negative pressure control in pneumatic soft robots

A key challenge in soft robotics is controlling the large deformation experienced as a result of high compliance nature of soft robots. In this work, a software control strategy for regulating the amount of internal positive and negative air pressure inside pneumatic soft robots is presented. Since the air pressure has a direct effect on the amount of deformation, the position of the robot is controlled. Pressure control was implemented with a fuzzy logic controller, which is described with its performance shown. The approach can be integrated into any specified soft robotic actuator requiring pneumatic actuation e.g. bending, triangular and muscle actuators

Development of soft modular robotics

This thesis covers the development and validation of soft robots in providing upper limb assistive motion. The main purpose of this research is to develop highly compliant and resilient actuators that generate motion for elbow and shoulder movements. To accomplish the purpose of the study, the fabrication, geometric construction along with experimental data of pressure, torque and range of motion of all developed actuators are described. The main contribution of this thesis is the development of soft actuators that transfer force via elastic deformation in order to generate assistive motion; features such as flexibility and soft contact with the skin ensure excellent safety potential of the actuators. To reduce the instability phenomenon attributed to the elastic response of rubber under large deformations that leads to bulging, the implementation of a pleated network design and embedded braided mesh network is presented. Bulging was reduced and torque output was increased with the integration of braided mesh into the silicone rubber actuator. The soft actuators developed for elbow and shoulder motion was tested on ten healthy participants thereby demonstrating its comfort, ease of use, fitting and removal as well as its practicality as an assistive apparatus for stroke patients. The use of soft robotics to provide shoulder motion was also assessed by the integration of soft robotics with a gravity compensated exoskeleton. The developed soft actuators were powered with electro-pneumatic hardware components presented in a compact, embedded form. Positive and negative air pressure control was implemented by a piecewise linear control algorithm with the performance of the controller shown. The design of a novel muscle made entirely of silicone rubber that contract upon actuation was described together with the manufacturing procedure, design parameters and measurement results of performance of these muscles such as the velocity of shortening, isometric contraction and maximal obtainable muscle force (without shortening). The muscles are manufactured to mimic the skeletal muscles present in the human body. These muscles are composed of a number of wedge-like units in series, the number of these wedge units increase the contraction. The soft muscles were characterized in order to find optimum design parameters that results in more contraction and speed; the muscles were tested on a model hinge joint to execute flexion/extension of the forearm at the elbow. Aside from contracting, the muscle has an interesting capability of producing bidirectional bending by the regulation of internal positive and negative air pressure in each wedge unit. In order to measure performance data relating to range of motion from bending, rotary and muscle actuators, computer vision processing was made use of. Soft robots are made with materials that experience large deformations, the sensors used to obtain measurement data can either be through the use of embedded sensors or visual processing. The use of embedded sensors can be cumbersome, resulting in limitation of its performance. The visual processing algorithms implemented to measure performance data such as angle of motion, bending angle and contraction ratio in real-time using a Webcam is described. Visual processing concepts such as colour tracking, template matching, camera calibration were applied. The developed vision system was applied to execute vision based motion control which is able to move the soft robot to a desired position using high level vision control and lower level pressure control. The material described in the preceding paragraphs are presented in an interrelated format. A concise introduction to the thesis is presented in the first chapter. An extensive survey of the field of soft robotics including materials, manufacturing procedure, actuation principles, primary accomplishments, control and challenges are presented in the literature review chapter, together with a review of rehabilitation devices. Since this work focused on the use of silicone rubber as actuator material, a brief introduction to working with silicone rubber as an engineering material is presented in the third chapter. The conclusions of the work and suggestions for future research are provided at the last chapter of this thesis

A compact low-cost electronic hardware design for actuating soft robots

A low cost, compact embedded design approach for actuating soft robots is presented. The complete fabrication procedure and mode of operation was demonstrated, and the performance of the complete system was also demonstrated by building a microcontroller based hardware system which was used to actuate a soft robot for bending motion. The actuation system including the electronic circuit board and actuation components was embedded in a 3D-printed casing to ensure a compact approach for actuating soft robots. Results show the viability of the system in actuating and controlling siliconebased soft robots to achieve bending motions. Qualitative measurements of uniaxial tensile test, bending distance and pressure were obtained. This electronic design is easy to reproduce and integrate into any specified soft robotic device requiring pneumatic actuation

Development of a wearable assistive soft robotic device for elbow rehabilitation

The loss of motor function at the elbow joint can result as a consequence of stroke. Stroke is a clinical illness resulting in long lasting neurological deficits often affecting somatosensory and motor cortices. More than half of those that recover from a stroke survive with disability in their upper arm and need rehabilitation therapy to help in regaining functions of daily living. In this paper, we demonstrated a prototype of a low-cost, ultra-light and wearable soft robotic assistive device that could aid administration of elbow motion therapies to stroke patients. In order to assist the rotation of the elbow joint, the soft modules which consist of soft wedge-like cellular units was inflated by air to produce torque at the elbow joint. Highly compliant rotation can be naturally realised by the elastic property of soft silicone and pneumatic control of air. Based on the direct visual-actuation control, a higher control loop utilised visual processing to apply positional control, the lower control loop was implemented by an electronic circuit to achieve the desired pressure of the soft modules by Pulse Width Modulation. To examine the functionality of the proposed soft modular system, we used an anatomical model of the upper limb and performed the experiments with healthy participants

Design and validation of exoskeleton actuated by soft modules towards neurorehabilitation - vision-based control for precise reaching motion of upper limb

We demonstrated the design, production, and functional properties of the Exoskeleton Actuated by the Soft Modules (EAsoftM). Integrating the 3D printed exoskeleton with passive joints to compensate gravity and with active joints to rotate the shoulder and elbow joints resulted in ultra-light system that could assist planar reaching motion by using the vision-based control law. The EAsoftM can support the reaching motion with compliance realised by the soft materials and pneumatic actuation. In addition, the vision-based control law has been proposed for the precise control over the target reaching motion within the millimeter scale. % Aiming at rehabilitation exercise for individuals, typically soft actuators have been developed for relatively small motions, such as grasping motion, and one of the challenges has been to extend their use for a wider range reaching motion. The proposed EAsoftM presented one possible solution for this challenge by transmitting the torque effectively along the anatomically aligned with a human body exoskeleton. % The proposed integrated systems will be an ideal solution for neurorehabilitation where affordable wearable and portable systems are required to be customised for individuals with specific motor impairments

Development of an E-Commerce Chatbot for a University Shopping Mall

Chatbots have been used in many fields ranging from education to healthcare and are also used in e-commerce settings. This research aims at developing a web-based chatbot called Hebron for the Covenant University Community Mall. The chatbot is developed using Python and React.js as the programming languages and MySQL (Structured Query Language) server as the database to give a structure to the e-commerce datasets and Admin Portal process. The e-commerce chatbot application for Covenant University Shopping Mall (CUSM) seeks to provide an easy, smart, and comfortable shopping experience for the Covenant University Community

Design and construction of a foam-based piezoelectric energy harvester

Generating, converting, harvesting and storing energy are crucial parts of society. This work aims to design and construct a piezoelectric generator that harvests energy from pressure to produce an output voltage capable of charging and powering low-energy electronic devices such as mobile phones and 5 V light bulbs. Proteus 8.0 professional software is used to simulate the circuit for construction. A piezoelectric disc transducer, which is the principal component, was used in the construction. The result shows a voltage of 5–12 V capable of powering low-voltage electronic devices. Amidst the constant instability in electric power systems in Nigeria, those in rural areas have little or no electricity access. Electronic and communication devices are necessary to connect community members to those outside their communities and the world wide web for global information. Children and youths require lighting facilities at school and home for further studies. The design will provide an alternative for energy supply to areas with little or no access to electricity

Movement intention based Brain Computer Interface for Virtual Reality and Soft Robotics rehabilitation using novel autocorrelation analysis of EEG

Brain Computer Interface (BCI) could be used as an effective tool for active engagement of patients in motor rehabilitation by enabling them to initiate the movement by sending the command to BCI directly via their brain. In this paper, we have developed a BCI using novel EEG analysis to control a Virtual Reality avatar and a Soft Robotics rehabilitation device. This BCI is able identify and predict the upper limb movement. Autocorrelation analysis was done on EEG to study the complex oscillatory processes involved in motor command generation. Autocorrelation represented the interplay between oscillatory and decaying processes in EEG which change during voluntary movement. To investigate these changes, the exponential decay curve was fitted to the autocorrelation of EEG windows which captured the autocorrelation decay. It was observed that autocorrelation decays slower during voluntary movement and fast otherwise, thus, movement intention could be identified. This new method was translated into online signal processing for BCI to control the virtual avatar hand and soft robotic rehabilitation device by intending to move an upper limb. The soft robotic device placed on the joint between upper and the lower arm inflated and deflated resulting to extension and flexion of the arm providing proprioceptive feedback. Avatar arm viewed in virtual 3D environment with Oculus Rift also moved simultaneously providing a strong visual feedback