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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...
In order to exert large force on an environment, it is effective to apply impulsive force. We describe the motions that perform tasks by applying impulsive force as “impact motion.” The objective of an impact motion is to exert large force on an environment, however if the impulsive force is too large, the robot may fall down due to the reaction force. This paper presents an optimization scheme to...
Dynamic maneuvers have been successfully implemented on many prismatic legged robots. Systems with articulated legs of significant relative mass pose more of a challenge in part due to the physics of thrusting with rotating limbs, which results in undesired non-vertical impulses, and in part due to the control problem of synchronizing ankle and knee joints. Presented here is an experimental articulated...
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...
This paper describes a control strategy for throwing motion of the springed Pendubot based on the concept of unstable zero dynamics. An underactuated two-link planar robot called the Pendubot is investigated to realize dexterous actions of the superior limb in human throwing motion. A torsion spring is mounted on the passive joint of the Pendubot representing the flexibility of the cubital joint....
In this paper, we deal with an analysis and a synthesis of stable grasp by a multi-fingered robot hand with compliance control. The stability of a grasped object by the fingers with linear elastic stiffness is firstly analyzed. A sufficient condition with the gravity effect is driven with respect to the contact points, the elastic coefficients and the mass of the grasped object. A compliance controller...
This paper illustrates the practical application of non-iterative correlation-based tuning with guaranteed stability. In this method, a sufficient condition for closed-loop stability is defined as the H∞-norm of a particular error function. This norm is then estimated using data from one closed-loop experiment. The method is applied to a pick-and-place robot. It is shown that the proposed constraints...
Asymptotic stability is a minimum requirement to be met in control and observation exercises. Quantification and control of the transient behavior is generally stated as non-convex optimization problem which involves additive penalty to asymptotic stability. In this paper, a convex-optimization approach to nonlinear observer design with robustness of transient behaviors is presented. It is shown that...
In this paper, an observer-based indirect adaptive fuzzy output feedback control scheme is proposed for a biped robotic system. Fuzzy logic systems are employed to approximate the biped unknown nonlinear functions. Based on the fuzzy system, a state observer is designed for estimating the states of the controlled system. In addition, we use a regularized inverse function to overcome the control singularity...
In this paper, we carry out a transparency (i.e., haptic realism) analysis and propose a haptic synchronization scheme for a force-reflecting teleoperation over time-varying network delay. Although previous researches proposed several haptic synchronization schemes to efficiently compensate for delay jitter, defining a proper synchronization delay for transparency improvement remains a challenge....
In order to solve the problem of impact in robotic force position control during the initial state, the hyperbolic tangent filter function which was constituted a non-linear PID was used to process tracking error and speed. A robot force and position controller without impact was achieved. The Popov method was applied to prove the stability of the system. Based on the force and position control experiment...
In this paper, an adaptive fuzzy sliding-mode formation controller (AFSFC) is designed to accomplish the formation tracking control of multi-robot systems. The multi-agent system with the proposed AFSFC can reach the desired formation asymptotically. Based on an adaptive tuning scheme, the external disturbances are dealt with and the analysis of the control stability is given. The simulation results...
A three-channel bilateral control system which is hybrid of position control and force control in the acceleration dimension based on disturbance observer gets unstable in contact with environments under time delay. In this control system, the sum of master force and slave force is controlled to zero in common modal space to realize the law of action-reaction. This paper proposes a velocity damping...
This paper presents a sliding mode-based impedance controller for delayed dual user teleoperation system with unknown delay. The latency which has considerable undesirable effects on system stability and performance is compensated through this control approach. The nonlinear gain of the controller is achieved independent of time delay caused by communication channels. Therefore, the necessity of measurement...
This paper presents an adaptive PD control scheme for multiple autonomous underwater vehicles (AUVs). The proposed adaptive PD controller with uncertain gravitational and buoyancy forces requires only model of gravity and buoyancy regressor matrix and does not need any knowledge of inertia matrix, Coriolis and centripetal force, hydrodynamic damping and the parameters of the gravity and buoyancy forces...
Welding is an important material processing method and widely used in industry. With the development of technology and the realization of the welding process, the required weld quality is higher and higher; applying the robot to the welding process is a revolutionary development, which totally changes the typical mode of rigid atomization to the flexible mode. Welding robot are made up of robot, robot...
Compared with mechanical steering system, hydraulic steering system and electric power assisted system, Steer By Wire (SBW) system has the advantage of variable steering ratio, easy assembling and enhancement of active safety, etc.. Due to only electric link but no mechanical link between steering wheel and front wheel, the force between front wheel and steering wheel, which is of great importance...
In the paper trajectory tracking algorithm including collision avoidance behaviour is presented. Dynamic properties of the robots are taken into account. Obstacles are assumed to be convex. Artificial potential functions (APF) are used to avoid collisions between robots and with static obstacles in the environment. Stability proof for the presented algorithm is shown and simulation results are presented...
Based on motion characteristics of the upper-limb rehabilitation robot in the rehabilitation training, the article proposes to use a new method of repetitive control to restraining joint position error for upper-limb rehabilitation robot control system. First, repetitive motion of joint position regards as a fixed-cycle signal, and then designs a repetitive controller according to motion characteristics...
This paper proposes a task space trajectory tracking controller based on resonance for multi-joint robots. This controller generates desired motions, which are specified in the task space, while adjusting stiffness of mechanical elastic elements installed in each joint of the robots. This controller also adjusts equilibrium angles of the elastic elements. These parameter adjustments minimize actuator...
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