Dynamic based control strategy for haptic devices

Abstract

Transparency is a key performance measure for haptic devices. In this paper, we investigate a control strategy to increase the transparency of a haptic device. This control strategy is based on careful analysis of the dynamics of the haptic device, computed torque feed forward control and current feedback based force control. The inverse dynamic equation of motion for the device is derived using Lagrangian formalism and the dominating terms are identified for some representative motion trajectories. The user contact dynamic model is identified using experiments on the device with different users. A PI controller using motor current measurements is used to follow the reference force from the virtual environment. Experimental results illustrate the effectiveness of the control strategy.

A Survey of the Current Status of Force-Feedback Manipulator

“…In the aspects of control method, it's a key part to improve the resistance range of the system and the stiffness of the master manipulator along with keeping the system transparent and stable [14,15]. Khan Suleman has put forward a new control method of force-feedback equipment based on dynamic model, which is also similar to the current loop control strategy developed by Yuru Zhang [17]. The new method uses Lagrange equation to build the dynamic model for the force-feedback equipment, in order to compensate the inertia and friction force of the system.…”

“…The model of force-feedback equipment and environment model are simplified as one-dimensional dynamic model and spring model in this algorithm. Feedback moment is calculated by measuring the current of each drive motor in order to realize the control by moment loop PID.Khan Suleman has put forward a new control method of force-feedback equipment based on dynamic model, which is also similar to the current loop control strategy developed by Yuru Zhang[17]. The new method uses Lagrange equation to build the dynamic model for the force-feedback equipment, in order to compensate the inertia and friction force of the system.…”

Design and Testing of Two Haptic Devices Based on Reconfigurable 2R Joints

“…A haptic device is an instrument that is used to perform different kinds of manipulations with objects, providing the operator with feedback, i.e., tactile feedback, vibrational feedback, force feedback, etc. The application of haptic devices varies from handling virtual three-dimensional (3D) bodies [1,2] to device remote control [3][4][5] and surgery [6,7]. Different types of feedback can be used to indicate the interaction with the controlled object.…”

“…Different types of feedback can be used to indicate the interaction with the controlled object. Some devices provide vibrational feedback [8][9][10] and others can implement torque [6] or force feedback [2,[11][12][13]. The most widely used architectures of haptic devices are serial [2,7] parallel [6,13,14] or cable drive-based architectures [15].…”

“…Regarding the most common type of joints that are implemented in commercial robots and manipulators, universal and spherical joints are among the most widely used in parallel manipulators. They are utilized in Delta robots and Stewart-Gough platforms and in haptic devices that share a similar architecture [6,14]. Spherical joints and mechanisms have been applied in commercially available serial haptic devices.…”