Sharif Digital Repository

The purpose of this research is the conceptual design of an aerial robot that has the ability to reach different locations without changing its horizontal attitude. The main missions of the aerial robots are monitoring and delivery, in which none of them requires the robot to leave its horizontal attitude. The main task of the robot is to deliver the goods to the specified points. In order to do this, it must have an appropriate container for carrying the cargo, high safety to prevent damage to the cargo and individuals, the ability to carry out missions when one of the subsystems exits, and the appropriate flight speed for Deliver cargo to the customer as fast as possible. All of the... 

The main goal of controlling overhead crane systems is to safely transfer the load to its desired position with maximum speed and accuracy, as well as to minimize or eliminate load oscillations. The overhead crane system is considered as an underactuated mechanical system in which the number of control inputs (actuators) is less than the number of degrees of freedom. In addition, overhead crane systems are generally associated with parametric or unmodeled uncertainties. Also, in these systems, external disturbances such as wind have a destructive effect on the system's performance. In addition, if the overhead crane has the hoisting mechanism and the length of the rope changes as the trolley... 

Human walking is widely recognized as one of the most adaptable and robust forms of locomotion in nature, with intricate neural and biomechanical systems interacting to support this complex behavior. It is proposed that these systems are organized in a hierarchical structure, with the lower level comprising a complex distributed system consisting of muscles and the spinal cord, and the higher level being the brain cortex. The higher level is responsible for training and monitoring the output of the lower level, and intervening when the lower system fails to stabilize the system. To control the lower level, one popular model that has emerged is the central pattern generator (CPG). It is... 

Foot movement is one of the most powerful and adaptable methods of movement in nature. Inspired by humans, the most intelligent creatures on earth, bipedal robots have many uses. In this research, a control method for running a bipedal robot has been designed. In the simulation part of the five-link model, the robot's motion equations for running and walking at different levels are extracted by the Lagrange method. In path generation, using the two-layer optimization method and holonomic and dynamic constraints, optimal paths are produced which are kinematically and dynamically possible (feasible). Additionally, path generation is facilitated by an invariant impact constraint to ensure the... 

Walking-robots have received much attention because of the variety of motion maneuvers they can produce and the many applications they have in various areas including rehabilitation. One of these maneuvers is running. In this study, a time-invariant controller is designed to dynamically stabilize a five-link and a seven-link running-robots in two dimensions. In the simulation of the seven-link model, an attempt has been made to measure the impact of the circular foot on the stepping pattern. Also, it is tried to present a dynamically simple model similar to the geometry of the human body. Simulations are performed in MATLAB software. The running is modeled with three phases of stance, flight... 

Compliant mechanisms are generally used in quasi-static condition and therefore system dynamics do not have a significant effect on their performance; But if the inertia of the links is high, the dynamics of the mechanism will affect its performance altogether. By cleverly designing the mechanism, these effects can be used to create new movement patterns. In this research, a family of compliant mechanisms is introduced whose movement patterns are a function of input speeds. This means that at low speeds, the flexibility of the mechanism does not have a significant effect on its performance, but when the speed exceeds a certain limit, this flexibility changes the configuration of the... 

In this work inspiring from the nature a control method is proposed for a stable rhythmic walking in a seven-link underactuated biped robot. Stable walking is a very important issue in biped robots and proposing a dynamically stable pattern of motion with the capability of acceleration and learning is our main purpose. It is tried that the presented method make the robot have a human like motion. This method controls dynamically the hybrid model of robot’s movement and stabilizes it by converging the time-invariant constraints considered to make this movement. Moreover, in addition to providing a suitable gait for the bipod robot, a robust control method is designed to improve the ability of... 

• Brachiation robot is a kind of under-actuated robots. A brachiating robot is a type of a mobile arm that is capable of moving from branch to branch similar to a long-armed ape. The purpose of this thesis is control of a two link Brachiation robot. The purpose of this thesis is control of a two link Brachiation robot using neural network and geometry control. For this purpose a genetic algorithm based training Neural Network is used to produce a suitable path for the second link of the robot and then using input-output linearization method, the second link is controlled to follow the path. The simulations shows that the Nero Controller designed in this thesis is suitable. The controller can... 

This thesis studies a brachiation robot that is a long armed locomotion similar to apes. The robot has 2 revolute joints but only one of them is actuated. In this thesis, after deriving dynamic model of the robot, the Controlled Lagrangian (CL) method is used for stabilization. The matching conditions satisfied for the controller are derived and the extended λ-method is used to solve PDE’s involved in the method of controlled lagrangian. Satisfactory controller’s gains are chosen by PSO algorithm. Feasibility of the developed controller is investigated by numerical simulations and finally, theoretical results are validated with experimental observations  

Robots have been widely used for various applications, especially during the last decades. Robots are made of several parts, in which, "Hand" is one of the most important of those. Hands are designed according to their applications and are not necessarily like human ones. Development of humanoid robots, however, brings a special place to human-like hands. In this research, a force-isotropic underactuated finger with two phalanxes and one actuator is designed, considering design limitations and through static analysis. Tendon, cam and mechanical lock (ratchet gear) are among the main components which have been considered in the finger design. Then, a model was fabricated and tested in order... 

In the present study, an adaptive sliding mode control method was employed to control a fish robotic system using the method of hardware in the loop. Following the introduction of the nonlinear model for the robot, elongated body theory, suggested by Lighthill, was used to analyze fish movements. Lighthill’s theory inspired from slender body theory in aerodynamics scope could be viable to exercise upon the carangiform mode of swimming. By simplifying Lighthill’s equations in planar motion of fish robot, the number of degrees of freedom exceeds the number of the control variables. In view of the fact that the presented model is an under-actuated model, there exist some parametric and... 

In robotic, Underactuated systems are interesting subject to study. Underactuated system, is a system that have fewer actuator than degrees of freedom. Underactuated systems are composed of active and passive joints. passive joints are existed, in order to decrease the weight, cost, and energy consumption. Usually, control of these systems are difficult. Underactuated systems have acceleration constraint. This property make the control method have fundamental constraint. So that controller dynamic could not be a smooth function of states of system. So most of standard method in control, such as feedback linearization, are not applicable. Local linearizing methods, because of...