To realize an ideal force control of robots interacting with humans, a very precise actuation system with zero impedance is desired. A flexible joint actuator may serve for this purpose. This paper presents the design of control algorithms to compensate for the impedance in the flexible joint actuator. To generate the torque as desired, a spring is installed between a motor and a human joint, a...

A technique using augmented sliding mode control for robust, real-time control of flexible multiple link robots is presented. For the purpose of controller design, the n-link, n-joint robot is subdivided into n single joint, single link subsystems. A sliding surface for each subsystem is specified so as to be globally, asymptotically stable. Each sliding surface contains rigid-body angular velo...

This paper addresses the issue of adaptive position/force control of uncertain constrained flexible joint robots (FJRs). The controller is developed without the assumptions of weak robot joint flexibility as adopted in popular singular perturbation (SP) approaches. It relies on the feedback of joint state variables and avoids noisy joint torque measurements found in most controllers developed s...

The regulation of motor variable positions in robots with elastic elements has been solved using PD linear controllers in the absence of gravity and with the addition of a model-based feedforward term when gravity is present. When the mass of the links is not known, an iterative learning scheme can be derived to obtain the same result for both joint elasticity and link flexibility. An extension...

This paper addresses the impedance control problem for flexible joint manipulators. An impedance controller structure is proposed, which is based on an exact decoupling of the torque dynamics from the link dynamics. A formal stability analysis of the proposed controller is presented for the general tracking case. Preliminary experimental results are given for a single flexible joint.

In this paper a robust composite control algorithm is proposed for flexible joint manipulators, with the emphasis on satisfying control effort limitations. An H∞ framework is used for the slow subsystem controller design, instead of robust PID synthesis introduced in the literature. Linear identification techniques are used to represent the nonlinear dynamics of the system into a linear model p...

We address the problem of (semiglobal) trajectory tracking control of rigid and exible joints robots using computed torque based controllers. The paper contains two contributions; rst, for rigid robots we show that velocity in the control algorithm can be replaced by the ltered position, thus obviating the explicit need of state observers. Second, we show that it is posible to achieve trajector...