A mute is a device that is placed in the bell of a brass instrument to alter its sound. However, when a straight mute is used with a brass instrument, the frequencies of its first impedance peaks are slightly modified, and a mistuned, extra impedance peak appears. This peak affects the instrument's playability, making some lower notes difficult or impossible to produce when playing at low dynam...

This paper proposes an impedance control method called the multi-point impedance control (MPIC) for redundant manipulators. The method can not only control end-effector impedance, but also regulate impedances of several points on the links of the manipulator, which are called virtual end-point impedances, utilizing arm redundancy. Two approaches for realizing the MPIC are presented. In the firs...

A human performs a variety of skillful movements by adjusting dynamic characteristics of his or her musculoskeletal system according to a task involved. Such characteristics of human movements can be described by mechanical impedance parameters. If the regulation mechanism of human impedance properties during the task can be clarified and modeled, there is a possibility that human skillful stra...

This paper suggests a new control method to modify the virtual impedance performance in unbalanced conditions. The proposed method compensates the voltage drop that occurred due to the virtual impedance and adjusts the voltage of the point of common coupling at a desirable level. To compensate the voltage drop, the reference voltage in the droop control varies according to the proposed algorith...

A typical passive mechanical isolation system utilizes a mass-spring-damper as a mechanical filter. Active isolation control systems typically include an electromagnetic transducer to develop the required control forces. In this paper, the technique of sensor-less active shunt control is applied to a mechanical isolation system. An electrical impedance is designed and connected to an electromag...

Mitral valvular regurgitation consistently modified the wave form of the first derivative of the transthoracic impedance cardiogram. The transthoracic impedance cardiogram was recorded in 23 control subjects (group 1), and 23 patients with isolated mitral regurgitation (group 2). Simultaneous transthoracic impedance cardiogram, electrocardiogram, and mitral valve echocardiograms in group 1 show...

Some active impedance control experiments in an anechoic chamber are reported. Further active methods are developed for the design of locally controlled absorption liners in air, whose basic principles were described by Olson and May and subsequently investigated practically by Guicking and his colleagues at the beginning of the 80’s. Two methods are described and tested. In the first, processi...

In impedance control for force tracking, it is well known that the reference trajectory of the robot is calculated from known environmental stiffness. The authors present a simple technique for determining the reference trajectory under the condition that the environment is unknown. The technique is developed based on the replacement of the unknown stiffness with a function of the measured forc...

Every unimpaired person in the world walks thousands of steps every day, and has an individual gait pattern, e.g. different velocities, load conditions, surrounding/ground conditions. Unfortunately, the number of lower-limb amputees has been increasing during the last centuries and millions of people are currently affected by amputation. To restore human walking abilities, an active knee prosth...