In this paper we present a robust hybrid motion/force controller for rigid robot Abstract manipulators. The main contribution of this paper is that the proposed hybrid control system is able to accomplish motion object ives in free direct ions and force object ives in constrained directions under parametric uncertainty both in robot dynamics and stiffness constraint constant. Also, the given sc...

This dissertation addresses the analysis and control of variable stiffness actuated robots aiming at precise, sensitive, robust, and dynamic interaction with their environment and especially humans. The focus is the adjustment of impedance properties, namely adjusting the robot equilibrium position, the stiffness, and damping. Highest demands are met by the development of new control concepts a...

In our movements and posture, we always act against a physical load. A key property of any load is its elastic stiffness (K), which describes how the force required to hold it must change with position. Here we examine how load stiffness affects the ability to maintain a stable posture at the wrist. Loads having positive (like a spring) and negative stiffness (like an inverted pendulum) were cr...

introduction: although, the effect of direct intra-articular injection of bone marrow stem cells (bmscs) on the repair of articular cartilage and the effect of elaeagnus angustifolia extract on pain relief in patients with osteoarthritis have been investigated, no studies has been conducted to compare the effects of these two therapeutic methods on the mechanical properties of articular cartila...

Dynamic joint stiffness determines the relation between joint position and torque, and plays a vital role in the control of posture and movement. Dynamic joint stiffness can be quantified during quasi-stationary conditions using disturbance experiments, where small position perturbations are applied to the joint and the torque response is recorded. Dynamic joint stiffness is composed of intrins...

Recent investigations on the longitudinal and lateral control of wheeled autonomous vehicles are reported. Flatness-based techniques are first introduced via a simplified model. It depends on some physical parameters, like cornering stiffness coefficients of the tires, friction coefficient of the road, . . . , which are notoriously difficult to identify. Then a model-free control strategy, whic...