Nazim Mir-Nasiri

New Intelligent Transmission Concept for Hybrid Mobile Robot Speed Control

This paper presents a new concept of a mobile robot speed control by using two degree of freedom gear transmission. The developed intelligent speed controller utilizes a gear box which comprises of epicyclic gear train with two inputs, one coupled with the engine shaft and another with the shaft of a variable speed dc motor. The net output speed is a combination of the two input speeds and is governed by the transmission ratio of the planetary gear train. This new approach eliminates the use of a torque converter which is otherwise an indispensable part of all available automatic transmissions, thereby reducing the power loss that occurs in the box during the fluid coupling. By gradually varying the speed of the dc motor a stepless transmission has been achieved. The other advantages of the developed controller are pulling over and reversing the vehicle, implemented by intelligent mixing of the dc motor and engine speeds. This approach eliminates traditional braking system in entire vehicle design. The use of two power sources, IC engine and battery driven DC motor, utilizes the modern idea of hybrid vehicles. The new mobile robot speed controller is capable of driving the vehicle even in extreme case of IC engine failure, for example, due to gas depletion.

Modelling and control of a novel hip-mass carrying minimalist bipedal robot with four degrees of freedom

The paper presents a simplified mathematical model of the bipedal walking robot with four degrees of freedom. It presents a novel sensing and balancing method for the bipedal robot with minimum possible for walk degrees of freedom. The proposed method involves the design of semi-rigid ankle to facilitate fast and accurate measurements of the sideway (sagittal) instability of the walking robot. The use of new hip-mass carrying strategy in forward direction and system of two counter masses for the sideway body balancing allows to decouple the forward walking algorithms from the robot stability restoring solutions. The system of two different masses helps to improve response time and efficiency of the balancing system. The developed control algorithms provide continuous stability of the robot while it walks in forward direction by means of only four DC actuators. The smooth legs trajectory planning is implemented to minimise the foot-ground impact and jerky motions at the joints. The efficiency of the proposed control algorithms are tested and verified by using MATLAB Simulink computer tools.

Design, modelling and control of four‐axis parallel robotic arm for assembly operations

This paper concerns a new robotic arm with a parallel structure, but with a functionality or geometry similar to the serial structure of a SCARA robot. However, it has a number of advantages compared to a SCARA robot and to other conventional manipulators with parallel structures. It has high stiffness, low inertia and a large payload with comparison to SCARA robots, and a larger workspace with comparison to conventional manipulators with parallel structures. This paper and related research is aimed at overcoming the problems encountered in the design, modeling and application of such robotic arms. In fact, the proposed structure has simpler and more manageable mathematical models compared to those of other 3D parallel structures.

Camera-based 3D Object Tracking and Following Mobile Robot

Camera-based systems are frequently used to track moving objects which are in the field of their view. This paper describes design and development of a camera-based tracking robot that can constantly track moving object without necessity of calibrating camera in real world units then control the two-wheeled moving platform to follow the object. The camera serves as a feedback sensor to guide robot constantly towards the object. The complexity of the system and processing time is less due to the unnecessary camera unit conversions and calibrations. The robot system consists of two subsystems: vision and motion. The vision subsystem consists of a two-motor pan-tilt camera driving mechanism with embedded potentiometer sensor, PCI image acquisition board, and PWM-based DC-motor driver board. The motion subsystem consists of two-wheel and two-castor platform driven by two DC servomotors with amplifiers. The vision subsystem identifies and locates the object in 3D scene by means of image processing techniques and motion control algorithms direct the camera towards the object. Camera motion is then detected by the potentiometer which generates a signal to drive the wheels of the platform. The objective of the vision control is to make sure that the moving object is always at the center of the camera image plane. The system imitates eye tracking ability of a human when he always tends to focus on moving object within the range of its view before any action is taken

Design and development of multi-nozzle extrusion system for 3D printer

3D printing or additive manufacturing is a process of producing three-dimensional solid objects from a software design. Color and material limitations for simultaneous usage, and relatively low printing speeds are the major problems of fused filament fabrication (FFF). In this study, an extrusion model with five nozzles is proposed to address the current deficiencies. The proposed extrusion model enables printing with five different colors and materials simultaneously without stopping the operational process while switching the filaments. The major advantage of the proposed model is that, the tailor made lightweight hot-end extruder is driven by only two motors. The proposed extrusion model provides a novel technique for 3D printing with multi-color and multi-material.

Dynamic modelling and walk simulation for a new four-degree-of-freedom parallelogram bipedal robot with sideways stability control

Abstract The paper presents a simplified mathematical model of a two-leg walking robot with four degrees of freedom. It presents a novel method of sensing and balancing for the bipedal robot with the minimum possible number of degrees of freedom for the walk. The proposed method involves the design of a semi-rigid ankle to facilitate fast and accurate measurements of the sideways (sagittal) instability of the walking robot. The use of a new hip-mass carrying strategy in the forward direction and a system of two counter-masses for the sideways body balancing enables us to decouple the forward walking algorithms from the robot stability issues. The system of two different masses helps to improve the response time and efficiency of the balancing system. The control algorithms developed provide continuous stability of the robot while it walks in a forward direction by actuating its four DC motors. Smooth leg trajectory planning is implemented to minimize the foot–ground impact and jerky motions at the joints. The efficiency of the proposed control algorithms is tested and verified by using MATLAB Simulink computer tools.

Tele-rehabilitation using in-house wearable ankle rehabilitation robot

Abstract This article explores wide-ranging potential of the wearable ankle robot for in-house rehabilitation. The presented robot has been conceptualized following a brief analysis of the existing technologies, systems, and solutions for in-house physical ankle rehabilitation. Configuration design analysis and component selection for ankle robot have been discussed as part of the conceptual design. The complexities of human robot interaction are closely encountered while maneuvering a rehabilitation robot. We present a fuzzy logic-based controller to perform the required robot-assisted ankle rehabilitation treatment. Designs of visual haptic interfaces have also been discussed, which will make the treatment interesting, and the subject will be motivated to exert more and regain lost functions rapidly. The complex nature of web-based communication between user and remotely sitting physiotherapy staff has also been discussed. A high-level software architecture appended with robot ensures user-friendly operations. This software is made up of three important components: patient-related database, graphical user interface (GUI), and a library of exercises creating virtual reality—specifically developed for ankle rehabilitation.

Higher-order derivative compensators for controlling the systems with higher dynamics

Abstract The PID controller is a popular choice for the control of industrial processes. The PDN controller introduced in this paper is a better alternative to PIDN. The paper presents the design and computer simulation of the PDN controller. The PDN controller is a simpler and more effective choice when dealing with higher-order dynamic systems. The gain components of the controller are introduced to improve transient characteristics of the higher-order industrial systems or processes by directly modifying the components of their characteristic equations. As a result the system under control becomes stable and able to respond faster to the inputs as compared to PID-based systems. The tunable command feed-forward steady-state gain (K S ) of the PDN controller helps to track the constant or time-varying input commands much faster and more precisely than the integral component of the PID controller. The paper discusses the steady-state performance, stability problems and the gain tuning strategies to improve the transient responses of the feedback system. The quality of the PDN performance is demonstrated by solving the set point input (step) and tracking a time-varying input (ramp) problems. The paper also presents the detailed higher-order derivative compensators tuning procedures for the general case of unknown order, stable/unstable plant and particular case of unknown order but stable plant.

DESIGN AND DEVELOPMENT OF AUTOMATED 3D VISUAL TRACKING SYSTEM

Abstract Camera‐based systems are frequently used to track moving objects which are in the field of their view. This paper describes design and development of a camerabased visual system that can constantly track a moving object without the necessity of calibrating the camera in real world coordinates. This reduces the complexity of the system and processing time due to unnecessary conversions and calibrations. The system consists of a two‐motor pan‐tilt camera driving mechanism, PCI image acquisition board, and PWM‐based DC‐motor driver board. It uses image processing techniques to identify and locate the object in the 3D scene and motion control algorithms to direct the camera towards the object. Thus the objective of the project is to develop a vision system and control algorithms which can be locked on a moving object within the field of its view. The developed software and related interface hardware monitor and control the motors in such a way that the moving object should always be located right at the center of the camera image plane. The system, in general, simulates the 3D motion of the human eye which always tends to focus on a moving object within the range of its view. It actually imitates the tracking ability of human eye.

An effective vision technique for microchip lead inspection

A new effective method for the microchip lead inspection for the chip manufacturing industry has been developed in this work. In contrast to the gray scale pattern matching technique this approach employs selected parameters of binary blobs to perform fault detection and measurements. This leads to a significant reduction of image processing time. A special combination of gray level filtering techniques with gray morphological operations enhances the borders of the lead images. Newly developed threshold calibration technique significantly improves the measurement accuracy. A unique statistical analysis has been developed to identify all possible lead defects in the chips. This method is rotationally and scale invariant and able to detect defective leads for the chips with different specifications. The minimum required information about the microchip is the number of leads.