Handheld Shear Force Feedback Controller with Double Roller Modules: A Demonstration

Force feedback controller (haptic device) is the key part of a master-slave tele-operation system. It can transmit its position, orientation and velocity to remotely operate the controlled object; at the same time it can acquire information of force/torque from the remote object, and rebuild those to the operator by enabling a force sense telepresence. In this paper, a new type force feedback controller with a 6 DOF Delta parallel mechanism is presented considering the performance of easy operation and precise force feedback. Firstly, the structure and control system of the force feedback controller are introduced, then its kinematics and statics models are analyzed as well as the force feedback control scheme. Moreover, a combined simulation model is established based on "Adams" and "Simulink" to valid the performance of the force feedback controller. Simulation results demonstrate that the established kinematic model and force feedback control scheme are precise and effective, which can provide beneficial guidance for design and application of the tele-operation system.

In minimally invasive surgery (MIS), haptic or force feedback control is used when the visual feedback is insufficient or unavailable. Haptics, or haptic technology, which is essential in simulating touch, provides both the kinesthetic and the tactile feedback. The lack of haptics in robotic-assisted MIS hinders the progression of operation when visual feedback reaches its limit. This paper aims to develop a single degree-of-freedom (DOF) haptic handle controller, using a proportional-integral (PI) control, that can quantify up to 1-N of force.

Scanning gel electrochemical microscopy (SGECM) is a novel technique measuring local electrochemistry based on a gel probe. The gel probe, which is fabricated by electrodeposition of hydrogel on a microdisk electrode, immobilizes the electrolyte, and constitutes a two-electrode system upon contact with the sample. The contact area determines the lateral physical resolution of the measurement, and considering the soft nature of the gel it is essential to be well analyzed. In this work, the lateral physical resolution of SGECM is quantitatively studied from two aspects: (1) marking single sampling points by locally oxidizing Ag to AgCl and measuring their size; (2) line scan over reference samples with periodic topography and composition. The gel probe is approached to the sample by either current or shear force feedback, and the physical resolution of them is compared. For the optimal gel probe based on 25 μm diameter Pt disk electrode of Rg ≈ 2, the lateral physical resolution of SGECM at contact position is ca. 50 μm for current feedback and ca. 63 μm for shear force feedback. More importantly, the lateral physical resolution of SGECM can be flexibly tuned in the range of 14-78 μm by pulling or pressing the gel probe after touching the sample. In general, current feedback is more sensitive to gel-sample contact than shear force feedback. But the latter is more versatile, which is also applicable to nonconductive samples.

For flexible robots with rotational joints it has been shown previously by Luo (1993), that direct strain feedback can damp out vibrations very satisfactorily. In this paper, a simple sensor-based output feedback control law, called shear force feedback, is newly proposed to control vibrations arising from structural flexibility of robots of Cartesian or SCARA types. Closed-loop exponential stability of such shear force feedback system is proved. Experimental results on set point control and trajectory tracking control are reported. It is found that the simple PI+shear force feedback can yield good performance for both robot motion and vibration suppression.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Functionality and performance of modern machines are directly affected by the implementation of real-time control systems. Especially in networked teleoperation applications, force feedback control and networked control are two of the most important factors, which determine the performance of the whole system. In force feedback control, generally it is necessary but difficult and expensive to attach sensors (force/torque/pressure sensors) to detect the environment information in order to drive properly the feedback force. In networked control, there always exist inevitable random time-varying delays and packet dropouts, which may degrade the system performance and, even worse, cause the system instability. Therefore in this chapter, a study on a real-time bilateral teleoperation control system (BTCS) over an imperfect network is discussed. First, current technologies for teleoperation as well as BTCSs are briefly reviewed. Second, an advanced concept for designing a bilateral teleoperation networked control (BTNCS) system is proposed, and the working principle is clearly explained. Third, an approach to develop a force-sensorless feedback control (FSFC) is proposed to simplify the sensor requirement in designing the BTNCS, while the correct sense of interaction between the slave and the environment can be ensured. Fourth, a robust-adaptive networked control (RANC)-based master controller is introduced to deal with control of the slave over the network containing both time delays and information loss. Case studies are carried out to evaluate the applicability of the suggested methodology.

Scanning electrochemical probe techniques have been widely applied for analyzing the local electrochemical activity of surfaces and interfaces. In this work, we develop a new concept of carrying out local electrochemical measurements by localizing both the electrode and the electrolyte. This is achieved through a gel probe, which is prepared by electrodepositing chitosan-gelatin gel on a microdisk electrode. It is positioned in contact with the sample surface by shear force feedback. The preliminary results indicate that the topography of the sample can be mapped by tapping the probe and recording the coordinates at a given normalized shear force signal, while the local electrochemical activity can be retrieved from local measurements with the probe touching the sample surface. The technique is denoted as scanning gel electrochemical microscopy. As compared with existing techniques, it has a major advantage of operating in air with the electrolyte immobilized in gel. This would prevent the spreading and leakage of solution on the sample surface and may lead to field applications.

Stabilization of coupled nonuniform Timoshenko beam system

This paper evaluates the performance of a new control scheme for bilateral master-slave teleo- perator, introduced earlier, and compares it to pub- lished control methods by using a mathematical cri- terion based on the two-port network model. It is shown that most of the published control laws under investigation do not achieve optimal performance, and the few that do, require perfect estimation (or exact knowledge) of the human operator or master arm dynamics. It is also shown that optimal performance, based on the selected mathematical criterion, can be obtained using the proposed control law: I. INTRODUCTION Teleoperating systems may be viewed as synergistic systems composed of human operators and master-slave manipulators which interact with the physical world. The master, sometimes called hand controller, is used to gen- erate commands (usually position, rate or force commands) to its remotedly located counterpart called slave. In gen- eral, the position/velocity command from the operator is fed forward to the slave, while the reaction force, due to mechanical interaction with the environment, is fed back to the master, providing contact force information to the human operator. By reflecting the measured force back to the master arm, it is said that the teleoperator is controlled bilaterally. One of the main issues in telerobotics is control of master-slave teleoperators. A number of control metho- dologies have been proposed in the teleoperator literature. There are two main methods for controlling master-slave teleoperators. The first, a more traditional approach, uses position and/or velocity error (between the master and slave) to generate a forcehorque command into the master arm. The position/velocity of the master and slave are measured by sensors usually located at the joints. The second method uses direct force feedback, rather than posi- tion and velocity errors, to generate command signals to the master. This method uses a force/torque signal obtained from a sensor, usually located at the end-effector of the slave, to provide the operator with the force feeling of the remotedly located counterpart. The force feedback control is usually considered superior because of the more precise nature of the feedback signal. The two-port model network theory has been exten- sively used for the analysis of circuits in which bi- directional energy flows are present at two distinct pairs of terminals. This method provides a useful linear representa- tion of complex networks which exchange energy. The two-port model theory is also used in bilateral teleoperator systems (1,3-81, with force and velocity sensing at the mas- ter and slave. The interfaces between the human operator and master, and between the environment and slave are ports through which the teleoperator is designed to exchange energy between the operator and environment. Recently, several algorithms have been proposed to

The architecture of an Internet-based teleoperation system with force feedback control has been presented. The notion of supermedia in the teleoperation was introduced firstly. And then the artificial potential field method was used to produce virtual force which was displayed by force feedback device. A kind of general task distribution algorithm had been proposed, in which tasks were distributed by the operator. Cooperating grabbing work experiment of the omnidirectional mobile robot and MOTOMAN manipulator in Shenyang Institute of Automation's had demonstrated that this method was available and effective

A design procedure for simultaneous position and force control is developed, using Lyapunov's direct method, for manipulators in contact with a rigid environment that can be described by holonomic constraints. Many manipulators that interact with their environment require taking into account the effects of these constraints in the control design. The forces of constraint play a critical role in constrained motion and are, along with displacements and velocities, to be regulated at specified values. Lyapunov's direct method is used to develop a class of position and force feedback controllers. The conditions for gain selection demonstrate the importance of the constraints. Force feedback has been shown not to be mandatory for closed-loop stabilization, but it is useful in improving certain closed-loop robustness properties.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Active tuned mass dampers as vibration-control devices are widely used in many fields for their good stability and effectiveness. To improve the performance of such dampers, a control method based on force feedback is proposed. The method offers several advantages such as high-precision control and low-performance requirements for the actuator, as well as not needing additional compensators. The force feedback control strategy was designed based on direct-velocity feedback. The effectiveness of the method was verified in a single-degree-of-freedom system, and factors such as damping effect, required active force, actuator stroke, and power consumption of the damper were analyzed. Finally, a simulation study was performed by configuring a main complex elastic-vibration-damping system. The results show that the method provides effective control over modal resonances of multiple orders of the system and improves its dynamics performance.

Recently, skill preservation of an expert has been a serious problem of the medical or production fields. It is difficult to acquire a human motion including touching motion by the conventional visual-based system. A touching motion is inherently bilateral, since an action is always accompanied by a reaction. A bilateral force feedback control is necessary to acquire the human's skill.This paper proposes a haptic teletraining system by multilateral force feedback control. Since the multilateral control transmits haptic information among three or more remote systems, it is possible to train remote trainee by one skilled trainer simultaneously. In the proposed haptic teletraining system, each local system consists of a master-slave system. Since a touching motion is subject to the “law of action and reaction”, it is possible to decompose the force information into action force and reaction force by using the bilateral control. Thus the skilled motion by a trainer is acquired and saved as a digital database integrated with his haptic information.The proposed system is applied to one-trainer/two-trainee system. As a result, a motion including contact with the environment is transmitted and trained with vivid force feedback. The experimental results show viability of the proposed method.

Lower limb exoskeleton rehabilitation robots represent an important development direction in modern rehabilitation technology. By integrating various sensors and control algorithms, these robots effectively enhance the specificity and efficiency of rehabilitation training. This paper systematically analyzes several widely used control methods, including position-based, force feedback, bioelectrical signal, and intelligent control strategies. Each strategy has its unique features and addresses different issues in the interaction between the robot and the patient, thereby improving the effectiveness and efficiency of rehabilitation training. For instance, position control provides stability and repeatability, force control ensures compliance, bioelectrical signal control offers rapid responsiveness, and intelligent control exhibits adaptability. Future research will focus on combining the advantages of different strategies to develop composite control methods that enable more efficient and personalized rehabilitation training, enhancing patient recovery outcomes and experiences

Active Systems - A Challenge of Contemporary Engineering

This paper presents a robotic catheter system with force sensors, monitor and a master-slave remote control system. We developed micro force sensors and applied them in the system to guarantee the operation safety in intravascular neurosurgery applications, and employed a camera to monitor the operation. Two kinds of force information are obtained through force sensors when the catheter contacted the blood vessel. The experiment shows that the proposed force sensors-based catheter system works well through force feedback and remote control. The system can facilitates the operation and avoid potential damages.