This paper presents a complete overview of basic strategies that have been proposed for force control of robot manipulators. First, the model of the plant to be controlled is reviewed. Next, the strategies are divided into force-based and position-based categories, according to previously reported implementations. Each of the controller types within these categories are analyzed, and predictions of stability and efficacy are made. Then it is shown that these two categories are actually the same, and this recognition leads to the concept of a novel second order low pass filter controller. Finally, all of the controllers are experimentally tested on the CMU DD Arm II , confirming the theoretical predictions. Among the important results presented is the conclusive demonstration for the first time that integral gain control is the best basic strategy for force control of manipulators. 1 Introduction Many automation tasks require manipulators to interact with their environments. Necessary ...

This paper discusses computational and experimental details necessary for successfully implementing and evaluating a wide variety of force control strategies. First, a review of both explicit force and impedance control strategies is provided. Second, the basic computational requirements of these schemes are discussed, and the hardware and timing information for our implementation is provided. Third, computational problems such as noise filtering and sampling rates are explained and discussed in detail. Finally, a review of the experimental results obtained is provided. These results support the previous discussions by demonstrating the importance of fully considering the implementational details required for successful force control of robotic manipulators.

This paper discusses the essential equivalence of second order impedance control with force feedback and proportional gain explicit force control with force feedforward. This is first done analytically by reviewing each control method and showing how they mathematically correspond for constrained manipulator control. For stiff environments the correspondence is exact. However, even for softer environments similar response of the system is indicated. Next, the results of an implementation of these control schemes on the CMU DD Arm II are presented, confirming the predictions of the analysis. These results experimentally demonstrate that proportional gain force control and impedance control, with and without dynamics compensation, have equivalent response to commanded force trajectories. 1 Introduction There is a whole class of tasks that implicitly require controlling the force of interaction between a manipulator and its environment: pushing, scraping, grinding, pounding, polishing, t...

This paper presents control methods for haptic telepresence and teleaction systems with Internet communication. Human rescuing systems are considered as one of the important application areas of telepresence technology. The stability and performance of telepresence systems with kinesthetic (force) feedback operated via a communication network with time-varying delay and underlying packet nature as for example the Internet is discussed. A stability condition in discrete time is derived from the continuous time case for time varying delays.

This paper presents the analysis and experimental verification of a fourth order model of the arm/ sensor / environment system plant, to be use in evaluation of force control strategies. Both the undamped and underdamped cases are investigated. Approximations and qualifications, based on the reality of our experimental system, help reduce the solution to just a few dominant terms. Comparing these terms with experimental data of the system undergoing small oscillations yields approximate values for all of the parameters in the model. To justify the obtained values, and thereby the approximations used, two measures are taken. First, a simulation of the fourth order model is performed, and compared against experimental data obtained from the CMU DD Arm II system. Second, a stability analysis of several force control schemes acting on the modelled plant is reviewed and compared against experimental tests of the controllers. In both cases, the simulation and analysis match closely with the ...

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