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An appearance-based similarity measure for localizing a robot along a route is presented. This measure assesses the likelihood that the robot lies between a pair of positions where snapshot images were captured during training. The change in the scale parameter of matched SIFT features is used to determined whether the robot lies ahead or behind each snapshot. Experimental results in two different...
The 40th anniversary of Apollo 11 project with man landing on the moon reminds the world again by what science and engineering can do if the man is determined to do. However, a huge step can only be achieved step by step which may be relatively small at the beginning. Robotic exploration can provide necessary information needed to do the further step safely, with less cost, more conveniently. Trajectory...
Often, electronics and packages must be prevented from damages resulting from awkward falls. The goal of this paper is to explore how actuators and control can be used to reorient bodies during free fall. It is well known that motion of a free-falling body or a set of interconnected bodies is characterized by the principle of conservation of angular momentum. The governing angular momentum equations...
BVP Path Planners generate potential fields whose gradient descent represents navigational routes from any point of the environment to a goal position. The resulting trajectories are smooth and free of local minima. In this paper, we proceed with our comprehensive study on possible forms for the core equation of the planner. The main goal is to allow the planner to deal with inhomogeneous environments...
Usually, the joint transmission friction model for robots is composed of a viscous friction force and of a constant dry sliding friction force. However, according to the Coulomb law, the dry friction force depends linearly on the load driven by the transmission. It follows that this effect must be taken into account for robots working with large variation of the payload or inertial and gravity forces,...
In this paper, Dual Differential Rheological Actuator (DDRA) is discussed. DDRA is an actuator with high performance torque and position control characteristics, in addition to versatile, safe, robust and easily controllable robotic interactions. DDRA's design is based on the use of two magnetorheological (MR) brakes coupled to an EM motor and to the system's output through a dual differential mechanism...
This paper presents an adaptive backstepping sliding-mode motion controller using fuzzy basis function networks (FBFN) method for trajectory tracking of a self-balancing two-wheeled robot (SBTWR) with parameter variations. A decoupling method is proposed to decouple the robot's dynamic model such that the tracking controller can be synthesized using backstepping and sliding-mode control in both kinematic...
Microrobots are widely used for microassembly and micromanipulation. However achieving performances compatible with the work in the microworld requires the use of bulky and expensive systems for measurement, signal processing and real time control. In this paper, we present the characterization and the control of a bistable module that can be used to build microrobots. This bistable module is fabricated...
A goal of our research is to produce a light-weight, low-cost five fingered robotic hand that has similar degrees of freedom as a human hand. The joints in the fingers of the developed robotic hand are powered by a newly proposed strings transmission named “Twist Drive”. The transmission converts torque into a pulling force by using a pair of strings that twist on each other. The basic characteristics...
For classical robotic applications, robotic systems consist of servo motors, high-ratio reduction and rigid links; mechanical designers prefer to designing robotic applications as stiff as possible to make robots manipulate with remarkable speed and precise position movements. However, these robotic applications can hardly interact with people and environments under safety constraints. It poses the...
The Time Domain Passivity Control Approach is gathering interest in the robotics field. Simplicity and flexibility and the fact that system design emerges from ideal cases make it a powerful stability tool for teleoperation systems. Communication time delay is an inherent attribute of nearly every realistic teleoperation system. Unless the communication channel guarantees transmission delays of less...
This paper presents a method for mapping captured human motion with stepping to a humanoid model, considering the current state and the controller behavior. The mapping algorithm modifies the joint angle, trunk and center of mass (COM) trajectories so that the motion can be tracked and desired contact states can be achieved. The mapping is performed in two steps. The first step modifies the joint...
In this paper we explore the effects of service level differentiation on a multi-robot control system. We examine the premise that although long interaction time between robots and operators hurts the efficiency of the system, as it generates longer waiting time for robots, it provides robots with longer neglect time and better performance benefiting the system. In the paper we address the problem...
Among numerous control schemes for flexible joint robots, the main problem is that the full state variable of acceleration and jerk must be known, which are difficult to measure, and the noise may be merged in the main signal. To solve this problem, a self adaptive composite control scheme is developed to control the flexible joint robots with modeling errors and subject to uncertain disturbances,...
In the design of wearable robots, the possibility of dynamically regulating the mechanical output impedance is crucial to achieve an efficient and safe human-robot interaction and to produce useful emergent dynamical behaviors. In this paper we propose a Variable Impedance Differential Actuator (VIDA) for wearable robotics applications. The system comprises two actuators (one being an impedance-controlled...
This paper describes the design and development of a new actuator with adjustable stiffness (AwAS) which can be used in robots which are necessary to work close to or physically interact with humans, e.g. humanoids and exoskeletons. The actuator presented in this work can independently control equilibrium position and stiffness by two motors. The first motor controls the equilibrium position while...
This article presents a control solution for the guidance of wheeled convoy units in non-linear trajectories. The proposal consists of a Mamdani fuzzy controller to solve the Decentralized Control problem as applied to a set of units following a leader, whilst guaranteeing the so called "string stability " condition of the convoy. Fuzzy control design is described for each of the follower...
Inverse kinematics computation has been one of the main problems in robotics research. An inverse kinematic analysis addresses the problem of computing the sequence of joint motion from the Cartesian motion of an interested member, most often the end effector. Traditional methods such as geometric, iterative and algebraic are inadequate if the joint structure of the manipulator is more complex. In...
This paper deals with path planning using cubic Hermite splines in real-time control of wheeled robots. The first part describes the filtering and prediction of the robot position. The discrete form of the extended Kalman filter is introduced on the basis of the robot model. The second part shows a computation of trajectories based on Hermite splines. The details of recomputation of the trajectory...
Extended Kalman Filter (EKF) has been a popular approach in localization of a mobile robot. However, the performance of the EKF and the quality of the estimation depends on the correct a priori knowledge of process and measurement noise covariance matrices (Qk and RK, respectively). Imprecise knowledge of these statistics can cause significant degradation in performance. In this paper, the Adaptive...
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