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Basic PD type iterative learning control algorithm has been applied to repeat control of trajectory tracking of manipulator. However, existing iterative learning control algorithm doesn't consider the effet of time delay between controller and actuator and between sensor and controller. Because of the existence of time delay, the system using PD type iterative learning control algorithm cann't keep...
Controlling states or outputs of technical processes to exact set points is not necessary in some technical applications. It may be sufficient to keep the state variables in defined regions. This fact can be utilized to formulate set point intervals. Hence the chance to reduce variations in manipulated signals and to increase the durability of actuators is offered. This paper presents an approach...
This paper addresses the problem of adaptive stabilization control and consensus control of diffusion system based on mobile multi-agents. Multi-agents triggered by events are integrated into diffusion system using self-measurement and neighbors information. Lyapunov redesign method is used to analyze adaptive feedback gain and consensus gain, and induce every agent trajectory. Then automatic guidance...
Aimed at the stabilization problem of the translational oscillator with a rotational actuator system(TORA) with unknown parameters, an adaptive state feedback controller with explicit form is proposed. The proposed controller is constituted by a feedback controller and an adaptive law of unknown parameters. The stability of the TORA under the proposed controller is proved. Finally, the effectiveness...
Time-optimal manoeuvres are the constrained time optimal slews which enable a spacecraft to attain a desired attitude in minimum time. The distinguishing feature of our work is that we consider arbitrary state transfer on the state space, not necessarily rest to rest manoeuvres. Further we work in a geometric framework, wherein the trajectories are analyzed on a cylinder. This report considers a special...
We consider the generation of time-optimal trajectories for an underactuated mechanical system including rigid body and vibrational modes. The considered model problem consists of two masses moving in a plane and linked together by springs. One of the masses is actuated in both directions, whereas the other one represents the tool center point (TCP) which should move on a given trajectory in the plane.
This paper addresses the problem of stability analysis of sampled-data control of linear systems in the presence of input magnitude and rate saturation. A position-type feedback modeling for the actuator is considered. Based on the use of a discrete-time quadratic Lyapunov function, a looped-functional and generalized sector relations (to cope with nested saturation functions), LMI conditions are...
The objective of this paper is to propose a new control strategy in the context of higher order sliding mode. In fact, the main result concerns a third order sliding mode controller which requires only the sliding variable and its first time derivative (whereas standard third order sliding mode controllers are using also the second order time derivative of the sliding variable). This reduction of...
This paper investigates a sensor-minimal approach to motion control in variable stiffness actuators. This control approach aims at reducing the need of sensors for tracking a desired trajectory. By this, problems caused by collocation and additional noise in measurement signals could get reduced along with economic benefits due to lower system complexity. Control laws are designed using a passivity-based...
It is challenging to realize robotic catching of small fast-moving targets in a large workspace, especially for targets with random trajectories that are difficult to predict. It requires high-speed and accurate motion control, whereas these two aspects usually conflict with each other due to the robot's nonlinear dynamics and systematic uncertainties like backlash. Previously, we proposed a dynamic...
Ageing society in many countries has led to an increasing number of stroke and cerebral palsy patients who require rehabilitation therapy. Affected wrist joints often show an increased spasticity and stiffness, caused by impairments of surrounding muscles and tendons. However, the medical devices for wrist joint assessment and rehabilitation are lacking. This paper proposes a robotic orthosis to assist...
In this work a new model for the twisted string actuation (TSA) was proposed and results were compared to the obtained data from various strings. Moreover, a wearable device was designed and fabricated, which was actuated by TSA. Joints were actuated by two antagonistic actuators. To simulate the motion of the elbow of the robot and validate the performance of the controller, a control test bed was...
In the present work, an economic model predictive control (EMPC) system is designed that accounts for the dynamics of the control actuators. A combined process-actuator dynamic model is developed to describe the process and control actuator dynamics and is used within the EMPC system. Stability constraints, designed via Lyapunov-based techniques, are imposed on the EMPC problem to guarantee closed-loop...
In this paper, a leader-follower formation control of multiple unmanned aerial vehicles (UAVs) design methodology is proposed to keep the desired formation, while simultaneously deal with the potential collision and actuator faults. The proposed formation control is divided into outer-loop and inner-loop controllers. First, a leader-follower control structure is constructed as the outer-loop controller...
We present implementation and experimental results of an Unmanned Ground Vehicle (UGV) navigation in a coordinate-free Wireless Sensor and Actuator Network (WSAN) environment. The UGV communicates with the network of sensors and actuators and receives the real-time feedback from the network, which navigates the UGV towards target(s). The control objective is to navigate the UGV towards fixed targets...
Ocean sampling for highly temporal phenomena, such as harmful algal blooms, necessitates a vehicle capable of fast aerial travel interspersed with an aquatic means of acquiring in-situ measurements. Vehicle platforms with this capability have yet to be widely adopted by the oceanographic community. Several animal examples successfully make this aerial/aquatic transition using a flapping foil actuator,...
Finite Element analysis can provide accurate deformable models for soft-robots. However, using such models is very difficult in a real-time system of control. In this paper, we introduce a generic solution that enables a high-rate control and that is compatible with strong real-time constraints. From a Finite Element analysis, computed at low rate, an inverse model of the robot outputs the setpoint...
Many control policies developed for legged robots are based on control of an underlying, simplified version of the dynamics of the robot. A good example is the Linear Inverted Pendulum Model (LIPM) which has become the standard control template for ZMP-based rigid robots. For compliant robots, this reduced order model is naturally the Spring-Loaded Inverted Pendulum (SLIP), which has proven to have...
Gliding robotic fish, a hybrid of underwater gliders and robotic fish, are energy-efficient and highly maneuverable, and hold strong promise for long-duration sampling of underwater environments. In this paper a novel systematic autonomous water-column-based sampling scheme for gliding robotic fish is proposed to measure the three-dimensional spatial distributions of variables of interest in aquatic...
The main objective of this paper is to perform a robust controller design using discrete-time sliding mode control (DSMC). In the control scheme, two-degree-of-freedom (2-DOF) control strategy turns the DSMC, which generally utilized state feedback into output feedback controller. The designed control scheme is considered with feedback and feedforward combination by implementing the zero phase error...
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