There are many works about bilateral teleoperation. However, good touch sense of remote object has not been realized in actual system yet. In this paper, the goals of bilateral teleoperation are considered as following two points. One is a reproduction of environmental impedance in master side. The other is a realization of small operational force. Operational force means the force the operator feels in addition to real environmental force. Corresponding to these goals, novel evaluation indices are defined which are named "reproducibility" and "operationality", respectively. Moreover, control stability must be satisfied. After all, bilateral teleoperation must satisfy three conditions such as reproducibility, operationality and stability. Using defined evaluation indices, bilateral controller is designed. Through analysis, it is confirmed that the three desired conditions in bilateral teleoperation are well satisfied with this controller. The effectiveness of this research is demonstrated by an experiment with bilateral forceps robot.

Reproducibility and operationality in bilateral teleoperation

http://www.ece.ualberta.ca/~tbs/pmwiki/pdf/CEP-Mohammadi-2012.pdf

Nonlinear Disturbance Observer Design For Robotic Manipulators

This paper presents a comprehensive overview of the application of Variable Structure Systems (VSSs) with Sliding Mode (SM) methods in motion control systems. Our aim is to give implementable sliding mode design solutions for complex motion systems, actuators and supply converters. This paper provides a frame for further study of sliding mode applications in motion control systems.

Variable Structure Systems With Sliding Modes in Motion Control—A Survey

Controlling robots in contact with the environment is an important problem in industry applications. Generally, a force sensor is used for sensing the external force. It is well known that information of a force sensor has much noise. Furthermore, unstable state is also caused by the narrow bandwidth of force information by a force sensor. This paper shows that stable contact with the environment is difficult when a force sensor is used because of its soft mechanical structure and narrow bandwidth of force sensing. In order to solve the instability of force control, the disturbance observer is implemented instead of the force sensor. The disturbance observer can observe the external force without force sensors. When the disturbance observer is implemented in a robot, a force control system does not include a soft mechanism between a robot and the environment. Since a robot can detect the environmental information directly, a wide bandwidth of force sensing is attained. In this way, this paper solves the problems of force control by considering the force sensing method without changing the control architecture, and the ability of force control is improved. Experimental results show viability of the proposed method

Modeling of Force Sensing and Validation of Disturbance Observer for Force Control

This paper studies the high performance robust motion control of an epoxy core linear motor, which has negligible electrical dynamics due to the fast response of the electrical subsystem. A discontinuous projection based adaptive robust controller (ARC) is first constructed. The controller theoretically guarantees a prescribed transient performance and final tracking accuracy in general, while achieving asymptotic tracking in the presence of parametric uncertainties. A desired compensation ARC scheme is then presented, in which the regressor is calculated using the reference trajectory information only. The resulting controller has several implementation advantages such as less online computation time, reduced effect of measurement noise, a separation of robust control design from parameter adaptation, and a faster adaptation rate. Both schemes are implemented and compared on an epoxy core linear motor. Extensive comparative experimental results are presented to illustrate the effectiveness and the achievable control performance of the two ARC designs.

Adaptive robust precision motion control of linear motors with negligible electrical dynamics: theory and experiments

Motion control is now recognized as a key technology in mechatronics. The robustness of motion control will be represented as a function of stiffness and a basis for practical realization. Target of motion is parameterized by control stiffness which could be variable according to the task reference. However, the system robustness of motion always requires very high stiffness in the controller. The paper shows that control of acceleration realizes specified motion simultaneously with keeping the robustness very high. The acceleration is a bridge to connect such robustness and variable stiffness. For practical applications, a technique to estimate disturbance is introduced to make motion controller to be an acceleration controller. Motion control of flexible structure and identification of mechanical parameters are also described.

Motion control for advanced mechatronics

Position-sensorless positioning servo systems for interior permanent magnet synchronous motors (IPMSMs) have been developed to achieve dimension and cost reduction. In these systems, parameter mismatch between the IPMSM, position controller, and position estimator due to thermal variation and aged deterioration is inevitable. To solve this problem, a parameter identification method based on an adaptive scheme has been proposed. However, to use the adaptive scheme, this method can only be applied under no-load conditions, and it is difficult to compensate for parameter variations during actual operation, i.e., under load conditions. 

/pdf/feedback-error-learning-based-position-control-in-position-1b65u7ke.pdf

M. Shibata

Papers

Motion control for advanced mechatronics

Feedback Error Learning-Based Position Control in Position-Sensorless Positioning Servo Systems for IPMSMs