Semi‐active vibration reduction based on a variable structure controlled serial‐stiffness‐switch‐system

PAMM ◽  
2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Chaoqing Min ◽  
Martin Dahlmann ◽  
Thomas Sattel
Keyword(s):  
Vibration Reduction ◽  
Variable Structure ◽  
Switch System ◽  
Active Vibration

scholarly journals Optimal switch timing for piezoelectric-based semi-active vibration reduction techniques

2017 ◽  
Vol 28 (16) ◽  
pp. 2275-2285 ◽  
Author(s):  
Christopher R Kelley ◽  
Jeffrey L Kauffman
Keyword(s):  
Vibration Reduction ◽  
Harmonic Excitation ◽  
Peak Displacement ◽  
Reduction Techniques ◽  
At Resonance ◽  
Near Resonance ◽  
Switch Time ◽  
Vibration Sensing ◽  
Dimensional Parameters ◽  
Active Vibration

Piezoelectric-based semi-active vibration reduction techniques typically rely on rapid changes in the electrical boundary conditions or corresponding stiffness state. Approaches such as state switching and synchronized switch damping on a resistor or an inductor require four switching events per vibration cycle, with switch timing associated with displacement extrema. Any deviation from this switch timing affects the performance of these techniques. Typical harmonic forcing analyses focus on the energy dissipation and only evaluate the performance at resonance. This study evaluates displacement reduction for harmonic excitation, both at resonance and for frequencies near resonance. Furthermore, it examines the effect of sub-optimal switch timings. Numerical simulations of a non-dimensional model are performed, and an analytical solution is derived for any switch time. This analysis shows that the optimal switch timing depends on the forcing frequency relative to the natural frequency of the structure. Thus, the classical switch time at peak displacement is only optimal when the excitation is exactly at resonance. Even when the optimal switch timing is known, uncertainties in vibration sensing cannot guarantee that switches will occur at the desired moment. Therefore, this work characterizes the degradation in vibration reduction performance when switching away from the optimal switch time based on global, non-dimensional parameters.

Effect of Switch Delays on Piezoelectric-Based Semi-Active Vibration Reduction Techniques

2015 ◽  
Author(s):  
Christopher R. Kelley ◽  
Jeffrey L. Kauffman
Keyword(s):  
Vibration Reduction ◽  
Local Strain ◽  
Electrical Energy ◽  
Peak Strain ◽  
Reduction Techniques ◽  
State Switching ◽  
Switch Time ◽  
Active Vibration ◽  
And Performance ◽  
The Ideal

Piezoelectric transducers have been used for semi-active vibration reduction in structures by altering the stiffness state and dissipating electrical energy. Common approaches include state switching, synchronized switch damping on a resistor (SSDS), and synchronized switch damping on an inductor (SSDI). Each of these methods requires four switches per vibration cycle, so any delay in the switch from the ideal moment could have a significant effect on the vibration reduction. An experimental investigation into the effect of switch delays on these techniques reveals that the abrupt change in piezoelectric voltage from the switch has the effect of a step input on the structure, which may excite higher order modes and increase the peak strain. This non-ideal switching of boundary conditions has implications towards the design and performance of these state switching techniques. Switching at the peak is classically considered the ideal switch time, but the influence of the switch on the local strain may actually result in a higher peak strain for the structure than with a delayed switch. This paper will examine switch times that lead and lag the ideal case for state switching, SSDS, and SSDI to quantify the level of vibration reduction achieved under non-ideal peak sensing.

Active Wide-Band Vibration Rejection for Semiconductor Manufacturing Robots

2015 ◽  
Author(s):  
Zining Wang ◽  
Cong Wang ◽  
Masayoshi Tomizuka
Keyword(s):  
Semiconductor Manufacturing ◽  
Experimental Validation ◽  
Control Strategies ◽  
Vibration Reduction ◽  
Wide Band ◽  
Controller Synthesis ◽  
Manufacturing Industries ◽  
Tracking Accuracy ◽  
Active Vibration ◽  
Active Vibration Cancellation

Currently, the semiconductor manufacturing industries over the world are upgrading from processing 300mm wafers to processing 450mm wafers. In order to satisfy the requirements of producing and processing 450mm wafers, vibration control of wafer handling tools has to make new breakthroughs. This paper introduces an active wide-band vibration rejection method with a vibrotactile actuator and applies it to a wafer transfer robot. Compared to conventional methods based on motor control of the robot, active vibration cancellation with a separate actuator does not risk compromising the tracking accuracy of wafer transfer motions. A three-step controller synthesis scheme is developed by analyzing and combining the strengths of several control strategies. Experimental validation shows a vibration reduction of more than 40% in energy and 30% in amplitude.

Autotuning of A PID Controller for an Active Vibration Suppression Device for the Treatment of Essential Tremor

2006 ◽  
Author(s):  
Nicholas Stone ◽  
Kenneth Kaiser ◽  
Robert D. White
Keyword(s):  
Essential Tremor ◽  
Pid Controller ◽  
Horizontal Plane ◽  
Vibration Suppression ◽  
Vibration Reduction ◽  
Active Vibration Suppression ◽  
Active Vibration ◽  
Linear Actuators ◽  
Inertial Actuator ◽  
System Operating

Essential Tremor (ET) is a motion disorder which affects as many as one in 20-25 adults over the age of 40 [1]. Leblanc [2] proposed a device which consists of four linear actuators attached to a patient's wrist in an effort to actively suppress the tremor. This paper demonstrates experimentally a simplified version of that device. The system was tested on a stand designed to simulate an adult lower arm with a tremor in the horizontal plane. A single linear inertial actuator was attached to the "wrist" of the test stand. An accelerometer attached on the opposite side of the arm provided feedback to the controller. This paper demonstrates this system operating to produce 20%-60% vibration reduction in the 6-13 Hz bandwidth.

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