Impedance control is a compliance control strategy capable of accommodating both unconstrained and constrained motions. The performance of impedance controllers depends heavily upon environment dynamics and the choice of target impedance. To maintain performance for a wide range of environments, target impedance needs to be adjusted adaptively. In this paper, a geometric view on impedance contr...

It is widely recognised that compliant actuation is advantageous to robot control once high-performance, explosive tasks, such as throwing, hitting or jumping are considered. However, the benefit of intrinsic compliance comes with high control complexity. Specifically, coordinating the motion of the system through a compliant actuator and finding a task-specific impedance profile that leads to ...

A new structural control system using damper-installed shear walls in lower stories with reduced stiffness is proposed for vibration control of high-rise RC buildings. That system has some design variables, i.e., height of shear wall, degree of stiffness reduction at lower stories, and quantity of dampers. In this paper, some parametric studies on the shearbeammodel with a stiff beam against tw...

To elucidate the relationship between coronary artery disease (CAD), aortic stiffness, and left ventricular structure, we recruited 55 subjects (33 men; average age, 63+/-1 years) with previously unknown CAD from a healthy general population sample, as well as 55 control subjects matched for gender, age, and serum cholesterol level. We measured arterial blood pressure and the systolic expansion...

In this paper we propose Variable Stiffness actuation [1] as a viable mechanical/control co–design approach for guaranteeing control performance for robot arms that are inherently safe to humans in their environment. A new actuator under development in our Lab is then proposed, which incorporate the possibility to vary transmission stiffness during motion execution, thus allowing substantial mo...

BACKGROUND Accelerated progression of aortic stiffness in patients with advanced chronic kidney disease is not well explained by the traditional cardiovascular risk factors. We hypothesized that vitamin K deficiency may result in an accelerated progression of aortic stiffness in the pro-calcifying uremic milieu. METHOD Eighteen hemodialysis (HD) patients on warfarin were matched to 54 HD pati...

Background: Knee osteoarthritis (OA) is one of the major causes of dysfunction that reduces patients’ quality of life. The aim of current study was to investigate the effectiveness of muscle strengthening exercises on the clinical outcomes of patients with knee OA. Methods: We conducted a single-blind clinical trial on 96 patients with mild to moderate knee osteoarthritis. Patients were random...

BACKGROUND Cerebral palsy causes motor impairments during development and many children may experience excessive neural and mechanical muscle stiffness. The clinical assumption is that excessive stiffness is thought to be one of the main reasons for functional impairments in cerebral palsy. As such, passive stretching is widely used to reduce stiffness, with a view to improving function. Howeve...

The problem considered in this paper is the design and analysis of a control strategy, for semi-active suspensions in road vehicles, based on Model Predictive Control (MPC) techniques. The optimal control law we compute using predictive techniques aims to optimize, the suspension performance, by minimizing a quadratic cost function while ensuring that the magnitude of the forces generated by th...

A control law combining motion performance quality and low stiffness reaction to unintended contacts is proposed in this work. It achieves prescribed performance evolution of the position error under disturbances up to a level related to model uncertainties and responds compliantly and with low stiffness to significant disturbances arising from impact forces. The controller employs a velocity r...