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The differences of force control capability among individual fingers have been studied in a wide range of contexts. However, the quantitative metric in term of the speed-accuracy tradeoff (SAT) between five fingers has not been systematically investigated. In this paper, we aim to explore this question by measuring SAT of each finger in a precision force control task. During the experiment, participants...
This work presents a system for hand rehabilitation, that makes use of an instrumented device and a virtual environment to provide augmented force and movement feedback to a patient, and data to a therapist. This system is aimed for use in occupational therapy, enabling remote and collaborative rehabilitation, as the environment allows recording of device data and remote streaming of the exercises.
This paper proposes a control strategy capable of reducing the vibration while keeping a low torque ripple for a switched reluctance machine (SRM). The aim is to minimize the variation of the radial force and to optimize the torque control parameters. At first, the torque ripple reduction method is introduced, for which an off-line optimization of control parameters is adopted. Then, the vibration...
Direct force control of robots is challenging, particularly since the interaction with the environment can render the robot unstable. This paper presents the results of novel approaches for passivity-based stability for a particular direct force control method, namely explicit force control. A step-by-step procedure to passivate and stabilise the control loop is presented and it explains how Time...
Impedance control based on robust force control can improves rehabilitation therapies. In this paper, we formulate and validate a model of a series-elastic-actuator-based ankle rehabilitation device that includes a second-order description of the human joint dynamics. In order to control the output impedance of the platform we used a cascade configuration with a PD position controller as outer loop...
Motion stabilization for electric vehicles (EVs) with four in-wheel-motors (IWMs) has been extensively studied in recent years. While most of the previous works have tended to focus on the development of optimization algorithms for driving force distribution, this paper considers a global-local control scheme: the global controller coordinates wheel and vehicle motions to generate reference driving...
A new advanced fault tolerant control technique for a triple three-phase Surface Permanent Magnet (SPM) machine is investigated in this paper. The machine has a nine-phase winding arranged in three sectors and supplied by three different Voltage Source Inverters (VSIs). The proposed current control technique is firstly exploited to avoid the radial force appearance in case of open winding of one machine...
The radial force control technique for a triple three-phase Surface Permanent Magnet (SPM) machine is investigated in this paper. The machine has a nine-phase winding arranged in three sectors and supplied by three different Voltage Source Inverters (VSI). A machine model is developed, based on the multi space vector approach. The multi space vector current control technique is exploited to control...
This paper presents a concept for a Forcebed that can manipulate a soft, articulated object, the human body while controlling the force applied to its surface. It is intended to automate tasks required to prevent pressure ulcers, or bed sores, in persons that have low-mobility or are otherwise at risk for developing them. The bed's hardware is composed of two main systems, a combination of rigid and...
This paper proposes a contact force control system for a dual-rotor helicopter. Force control of a helicopter allows for achieving aerial tasks that include contact motions with objects. Although one-degree-of-freedom force control systems have been already developed, multi-degree-of-freedom systems have not been achieved yet. Therefore, in this paper, a force control system for a dual-rotor helicopter...
Autonomous robot hand manipulation has attracted a lot of attention recently. Especially when the robot fingers reach the object, each finger requires the coordination between the position and the force control in free and constrained space. It is not guaranteed to be stable when switching between different control modes. Furthermore, after grasping the object, we also want the system to have the...
Robot manipulation is one of prerequisites capability for service robot. However, autonomous manipulation remains a challenging problem for robot to implement the task, where robot has physical interactions and mechanical contacts with its environment. To date, learning from demonstration (LFD) has been successfully applied to enable robot to acquire new manipulation skill. Researches on LFD mainly...
Industrial robot path planning for polishing is crucial to improve product quality. Current methods have many disadvantages: a) product quality is not consistent caused by the variations of part dimension, geometry and robot path accuracy; b) robot path planning is very challenging and time consuming. To solve these problems, we propose a polishing path planning method which is easy to use. A complex...
Body weight support (BWS) is important in rehabilitation robotic systems for patients with locomotion difficulties. We are building an active body weight support (ABWS) system that allows patients to move freely in the three dimensional Cartesian space and provides well-controlled supportive force against gravity. In the BWS unit, both the cable position and tension force on the cable should be controlled...
Traditional autopilots suffer from inherent flight path control objective conflict problems, as arbitrary flight path and speed targets cannot be maintained with saturated energy rate control. Elementary flight envelope protections are typically introduced to protect airspeed and prevent loss of control, but rather as a "last line of defense", than as a mean of smooth and deterministic control...
This paper proposes a data-driven design method of a force controller using input/output data of a force control system, i.e., force response obtained when contacting to an unknown environment and input to a robot at that time. The force control system includes the environment to be contacted in addition to the robot itself. The force controller must be designed in consideration of the environment...
This paper introduces a method of force control for a jumping biped robot to correctly control the ground reaction force during continuous jumping. Assuming dynamic motion, such as jumping and running, the attitude of the robot depends on the dynamics in response to the ground reaction force. Therefore, controlling the ground reaction force is necessary for stabilizing the robot's motion. However,...
We present GRAVITY-ASSIST, a series elastic active body weight support and inertia compensation system for use in robot assisted gait rehabilitation. The device consists of a single degree of freedom series elastic actuator that connects to the trunk of a patient. The series elastic system is novel in that, it can provide the desired level of dynamic unloading such that the patient experiences only...
With the rapid development of robotics, dual-arm robots have been more and more widely used. Compared with the traditional single manipulator, it is very challenging for a dual-arm robot in modelling, planning and control. In this paper, we propose two compliance control methods for dual arm coordination to meet different requirements of fine manipulation tasks, such as payload carrying, assembly...
The precise location of tumors is an important step in surgical planning that can be obtained from mechanical properties of soft tissues. In this paper we propose a robotic-assisted palpation system that automatically moves an ultrasound probe to optimize the elastography process and improve the resulting elastogram. The main contribution of this work is the use of the elastography modality directly...
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